Paul Witting

Vitamin E analogs trigger apoptosis in HER2/erbB2-overexpressing breast cancer cells by signaling via the mitochondrial pathway

Publisher: Elsevier BV

Date: 2005

DOI: 10.1016/J.BBRC.2004.11.028

Abstract: Alpha-tocopheryl succinate (alpha-TOS) is a redox-silent vitamin E (VE) analog with high pro-apoptotic and anti-neoplastic activity. Here we investigated whether alpha-TOS and several novel VE analogs kill breast cancer cells over-expressing the anti-apoptotic receptor protein HER2/erbB2. The agents induced apoptosis at comparable levels in both erbB2-low and -high cells. Generation of reactive oxygen species (ROS) preceded mitochondrial destabilization and execution of apoptosis, as evidenced by the anti-apoptotic effects of exogenous superoxide dismutase and mitochondrially targeted coenzyme Q. Dissipation of DeltaPsi(m) was followed by cytochrome c and Smac/Diablo re-localization and caspase-dependent cleavage of death substrate. A resistance to apoptosis for the corresponding rho(0) counterparts confirmed a critical dependency for mitochondria during the induction of apoptosis in breast cancer cells mediated by VE analogs and linked apoptosis to generation of radicals as judged by the delayed accumulation of ROS in the cybrid cell types. We conclude that alpha-TOS causes efficient apoptosis in breast cancer cells independent of their erbB2 status. Since erbB2 is frequently over-expressed in breast cancers and renders the neoplastic disease resistant to established treatment, our findings are of clinical interest.

α‐Tocopheryl succinate selectively induces apoptosis in neuroblastoma cells: potential therapy of malignancies of the nervous system?

Publisher: Wiley

Date: 07-07-2005

DOI: 10.1111/J.1471-4159.2005.03298.X

Abstract: Vitamin E (VE) analogues, epitomized by alpha-tocopheryl succinate (alpha-TOS), are potent inducers of apoptosis and anti-cancer agents. Here, we tested their effect on the highly malignant N-type neuroblastoma (Nb) cells and their differentiated, neurone-like counterparts. Nb cells were highly susceptible to several VE analogues, while differentiated Nb cells were relatively resistant to alpha-TOS. The importance of caspase-9 rather than caspase-8, as judged by specific siRNAs studies, together with the loss of the inner mitochondrial potential, suggests that alpha-TOS triggers apoptosis in Nb cells via the mitochondrial pathway. Cultured Nb cells were sensitized to alpha-TOS by pre-treatment with Bcl-2, Bcl-xL or Mcl-1 siRNAs, while the malignant cell line was more resistant to the vitamin E analogue when Bax was knocked down. In contrast, overexpression of Bcl-2 in Nb cells rendered them more resistant to alpha-TOS-induced apoptosis. The resistance of differentiated Nb cells to alpha-TOS-mediated apoptosis occurred via two modes: first, by up-regulation of the anti-apoptotic Bcl-2 family proteins and second, by accumulation of decreased levels of reactive oxygen species when challenged with alpha-TOS. We conclude that alpha-TOS is highly selective in killing malignant brain cancer cells while relatively inert toward differentiated neuronal cells, and that vitamin E analogues may be novel therapeutics for the treatment of tumours such as neuroblastomas.

A role for reduced coenzyme Q in atherosclerosis?

Publisher: Wiley

Date: 1999

DOI: 10.1002/BIOF.5520090216

Abstract: Substantial evidence implicates oxidative modification of low density lipoprotein (LDL) as an important event contributing to atherogenesis. As a result, the elucidation of the molecular mechanisms by which LDL is oxidized and how such oxidation is prevented by antioxidants has been a significant research focus. Studies on the antioxidation of LDL lipids have focused primarily onα‐tocopherol (α‐TOH), biologically and chemically the most active form of vitamin E and quantitatively the major lipid‐soluble antioxidant in extracts prepared from human LDL. In addition toα‐TOH, plasma LDL also contains low levels of ubiquinol‐10 (CoQ 10 H 2 the reduced form of coenzyme Q 10 ). Recent studies have shown that in oxidizing plasma lipoproteinsα‐TOH can exhibit anti‐ or pro‐oxidant activities for the lipoprotein's lipids exposed to a vast array of oxidants. This article reviews the molecular action ofα‐TOH in LDL undergoing “mild” radical‐initiated lipid peroxidation, and discusses how small levels of CoQ 10 H 2 can represent an efficient antioxidant defence for lipoprotein lipids. We also comment on the levelsα‐TOH, CoQ 10 H 2 and lipid oxidation products in the intima of patients with coronary artery disease and report on preliminary studies examining the effect of coenzyme Q 10 supplementation on atherogenesis in apolipoprotein E knockout mice.

Decrease in expression or activity of cytosolic phospholipase A2α increases cyclooxygenase-1 action: A cross-talk between key enzymes in arachidonic acid pathway in prostate cancer cells

Publisher: Elsevier BV

Date: 07-2010

DOI: 10.1016/J.BBALIP.2010.03.003

Abstract: The eicosanoid pathway is activated in many types of cancers including prostate. Eicosanoids are synthesized from intracellular arachidonic acid (AA), which is released from membrane glycerophospholipids mainly by the action of cytosolic phospholipase A(2)alpha (cPLA(2)alpha). Thus, targeting cPLA(2)alpha has been proposed as a treatment option. The aim of this study was to determine the effect of cPLA(2)alpha inhibition on cyclooxygenase (COX) expression and PGE(2) production. Inhibition of cPLA(2)alpha expression by siRNA or activity by Efipladib in prostate cancer cell lines (PC3 and LNCaP) led to an increase in COX-1 protein and PGE(2) levels in a dose-dependent manner from 24 to 72 h. The COX-2 response was less evident. Efipladib treatment increased COX-1 promoter transcriptional activity without changing the rate of COX-1 protein degradation. Treatment with Efipladib also led to a decrease in most LOX products (HETEs) as measured by LC/MS/MS. Replenishing 5- and 12-HETEs abolished Efipladib-induced COX-1 and PGE(2) levels. Decreasing 5- and 12-HETE production, as a result of treating cells with inhibitors MK886 and Baicalein, respectively, mimicked the effect of Efipladib on COX-1 and PGE(2) levels. Hence, the mechanism underlying the cPLA(2)alpha inhibition-induced COX-1 is likely due to a decrease in LOX products, which may exert a negative feedback on COX-1 gene expression in prostate cancer cells. Considering that PGE(2) is a potent promoter of cancer cell proliferation and survival, understanding the mechanism coupling cPLA(2)alpha with COX-1 is of potential clinical significance.

Evidence for Oxidative Pathways in the Pathogenesis of PD: Are Antioxidants Candidate Drugs to Ameliorate Disease Progression?

Publisher: MDPI AG

Date: 22-06-2022

DOI: 10.3390/IJMS23136923

Abstract: Parkinson’s disease (PD) is a progressive neurodegenerative disorder that arises due to a complex and variable interplay between elements including age, genetic, and environmental risk factors that manifest as the loss of dopaminergic neurons. Contemporary treatments for PD do not prevent or reverse the extent of neurodegeneration that is characteristic of this disorder and accordingly, there is a strong need to develop new approaches which address the underlying disease process and provide benefit to patients with this debilitating disorder. Mitochondrial dysfunction, oxidative damage, and inflammation have been implicated as pathophysiological mechanisms underlying the selective loss of dopaminergic neurons seen in PD. However, results of studies aiming to inhibit these pathways have shown variable success, and outcomes from large-scale clinical trials are not available or report varying success for the interventions studied. Overall, the available data suggest that further development and testing of novel therapies are required to identify new potential therapies for combating PD. Herein, this review reports on the most recent development of antioxidant and anti-inflammatory approaches that have shown positive benefit in cell and animal models of disease with a focus on supplementation with natural product therapies and selected synthetic drugs.

Lipid oxidation in human low-density lipoprotein induced by metmyoglobin/H2O2: Involvement of α-tocopheroxyl and phosphatidylcholine alkoxyl radicals

Publisher: American Chemical Society (ACS)

Date: 03-11-1999

DOI: 10.1021/TX9900472

Abstract: Metmyoglobin (metMb) and H(2)O(2) can oxidize low-density lipoprotein (LDL) in vitro, and oxidized LDL may be atherogenic. The role of alpha-tocopherol (alpha-TOH) in LDL oxidation by peroxidases such as metMb is unclear. Herein, we show that during metMb/H(2)O(2)-induced oxidation of native LDL, alpha-tocopheroxyl radical (alpha-TO(*)) and hydroperoxides and alcohols of cholesteryl esters [CE-O(O)H] and phosphatidylcholine [PC-O(O)H] accumulate concomitantly with alpha-TOH consumption. The ratio of accumulating CE-O(O)H to PC-O(O)H remains constant as long as alpha-TOH is present. Accumulation of CE-O(O)H is dependent on, and correlates with, LDL's alpha-TOH content, yet does not require preformed lipid hydroperoxides or H(2)O(2). This indicates that in native LDL alpha-TOH can act as a phase-transfer agent and alpha-TO(*) as a chain-transfer agent propagating LDL lipid peroxidation via tocopherol-mediated peroxidation (TMP). After alpha-TOH depletion, CE-O(O)H continues to accumulate, albeit at a slower rate than in the presence of alpha-TOH. This second phase of LDL oxidation is accompanied by depletion of PC-OOH, a rapid increase in the CE-O(O)H/PC-O(O)H ratio, formation of lipid-derived alkoxyl radicals and phosphatidylcholine hydroxides (PC-OH), and accumulation of a second organic radical, characterized by a broad singlet EPR signal. The latter persists for several hours at 37 degrees C. We conclude that metMb/H(2)O(2)-induced peroxidation of LDL lipids occurs initially via TMP. After alpha-TOH depletion, cholesteryl esters peroxidize at higher fractional rates than surface phospholipids, and this appears to be mediated at least in part via reactions involving alkoxyl radicals derived from the peroxidatic activity of metMb on PC-OOH.

Myeloperoxidase in Health and Disease

Publisher: MDPI AG

Date: 23-04-2023

DOI: 10.3390/IJMS24097725

Abstract: Innate and adaptive immune responses comprise a complex network of protein–protein and protein–cell interactions that regulates commensal flora and protects organisms from foreign pathogens and transformed (proliferating) host cells under physiological conditions such as pregnancy, growth and development as well as formulating a response pathological challenge [...]

Electrochemical Studies on the Competition Between Intramolecular Electron Transfer and Intermolecular Protonation of Nitroaryl Radical Anions in the Reductions of Apical Carboxylic Acid Substituents

Publisher: CSIRO Publishing

Date: 1997

DOI: 10.1071/C97076

Abstract: The results obtained from variable scan rate cyclic voltammetry (c.v.) on 2-nitro- and 3-nitro-9,10- dihydro-9,10-ethanoanthracene-9-carboxylic acids [(4) and (5), respectively], combined with simulations of various c.v. responses, are consistent with reduction of a benzylic acid group being facilitated by an intramolecular electron transfer process. This intramolecular process involves a one-electron reduction of the nitroaromatic group, followed by a rapid and irreversible π*(ArNO2)•- → π*(RCO2H)•- intramolecular electron transfer to the carboxylic acid group at a benzylic bridgehead position of the acids (4) and (5). The reduction potentials of the acid groups are shifted more than 0·3 V to positive potentials at slow scan rates (20-100 mV s-1) compared with the unnitrated acid derivative (6). The reduction potentials and the relative peak currents for the reductions of the nitro and acid groups for each of compounds (4) and (5) are dependent on the concentrations of the reactants. At concentrations of substrate mM, reduction of the acid moiety is increasingly dependent on complex intermolecular processes. These intermolecular processes compete with intramolecular electron transfer from the nitroaryl anion to the apical acid group at the benzylic bridgehead position. Digital simulations of the voltammetric data were confined to substrate concentrations mM, and show that the intramolecular reductions of the apical carboxylic acid protons of (4) and (5) are complicated by competing intermolecular electron transfer and intermolecular self-protonations of the nitro radical anions. The value of the intramolecular electron transfer rate constant for the meta compound is an order of magnitude larger than that for the para compound, which is the opposite reactivity pattern to that generally found in the SRN1 reactions of m- and p-nitrobenzyl halides. This indicates that there is likely to be an important contribution from an intramolecular through-space electron transfer mechanism for the former reaction

Mitochondrial Targeting of Vitamin E Succinate Enhances Its Pro-apoptotic and Anti-cancer Activity via Mitochondrial Complex II

Publisher: Elsevier BV

Date: 02-2011

DOI: 10.1074/JBC.M110.186643

α-Tocopheryl hydroquinone is an efficient multifunctional inhibitor of radical-initiated oxidation of low density lipoprotein lipids

Publisher: Proceedings of the National Academy of Sciences

Date: 22-07-1997

DOI: 10.1073/PNAS.94.15.7885

Abstract: As the oxidation of low density lipoprotein (LDL) lipids may be a key event in atherogenesis, there is interest in antioxidants as potential anti-atherogenic compounds. Here we report that α-tocopheryl hydroquinone (α-TQH 2 ) strongly inhibited or completely prevented the (per)oxidation of ubiquinol-10 (CoQ 10 H 2 ), α-tocopherol (α-TOH), and both surface and core lipids in LDL exposed to either aqueous or lipophilic peroxyl radicals, Cu 2+ , soybean lipoxygenase, or the transition metal-containing Ham’s F-10 medium in the absence or presence of human monocyte-derived macrophages. The antioxidant activity of α-TQH 2 was superior to that of several other lipophilic hydroquinones, including endogenous CoQ 10 H 2 , which is regarded as LDL’s first line of antioxidant defence. At least three independent activities contributed to the antioxidant action of α-TQH 2 . First, α-TQH 2 readily associated with LDL and instantaneously reduced the lipoprotein’s ubiquinone-10 to CoQ 10 H 2 , thereby maintaining this antioxidant in its active form. Second, α-TQH 2 directly intercepted aqueous peroxyl radicals, as indicated by the increased rate of its consumption with increasing rates of radical production, independent of LDL’s content of CoQ 10 H 2 and α-TOH. Third, α-TQH 2 rapidly quenched α-tocopheroxyl radical in oxidizing LDL, as demonstrated directly by electron paramagnetic resonance spectroscopy. Similar antioxidant activities were also seen when α-TQH 2 was added to high-density lipoprotein or the protein-free Intralipid, indicating that the potent antioxidant activity of α-TQH 2 was neither lipoprotein specific nor dependent on proteins. These results suggest that α-TQH 2 is a candidate for a therapeutic lipid-soluble antioxidant. As α-tocopherylquinone is formed in vivo at sites of oxidative stress, including human atherosclerotic plaque, and biological systems exist that reduce the quinone to the hydroquinone, our results also suggest that α-TQH 2 could be a previously unrecognized natural antioxidant.

Boronated phosphonium salts containing arylboronic acid, closo-carborane, or nido-carborane: Synthesis, X-ray diffraction, in vitro cytotoxicity, and cellular uptake

Publisher: Springer Science and Business Media LLC

Date: 06-08-2010

DOI: 10.1007/S00775-010-0690-6

Abstract: The preparation of boronated triaryl and tetraaryl phosphonium salts of the type [PPh(3)CH(2)R]Br [R is 4-boronophenyl (1), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-yl)phenyl (2), 3-boronophenyl (3), 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-yl)phenyl (4), 2-boronophenyl (5), 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-yl)phenyl (6), and closo-1,2-carboran-1-yl (7)] is described. These compounds were prepared by the reaction of triphenylphosphine with benzylic bromides or 1-bromomethyl-closo-1,2-carborane in acetonitrile solution at 85 °C. The zwitterionic nido-7,8-carborane derivative PPh(3)CH(2)C(2)B(9)H(11) (8) was prepared by treatment of 7 with cesium fluoride in refluxing ethanol. All compounds were fully characterized by multinuclear ((1)H, (11)B, (13)C, and (31)P) 1D- and 2D-NMR spectroscopy, electrospray ionization mass spectrometry, and elemental analysis, and single-crystal X-ray structures were determined for compounds 1, 3, 7, and 8. The cytotoxicities and boron uptake of selected derivatives were investigated in vitro using human glioblastoma (T98G) and canine kidney tubule (MDCK II) cells. The zwitterionic species 8 was found to be the least cytotoxic agent while also delivering the greatest amount of boron to the T98G cells, peaking at 9.15 ± 2.65 μg B/mg protein.

Physiological Benefits of Novel Selenium Delivery via Nanoparticles

Publisher: MDPI AG

Date: 23-03-2023

DOI: 10.3390/IJMS24076068

Abstract: Dietary selenium (Se) intake within the physiological range is critical to maintain various biological functions, including antioxidant defence, redox homeostasis, growth, reproduction, immunity, and thyroid hormone production. Chemical forms of dietary Se are erse, including organic Se (selenomethionine, selenocysteine, and selenium-methyl-selenocysteine) and inorganic Se (selenate and selenite). Previous studies have largely investigated and compared the health impacts of dietary Se on agricultural stock and humans, where dietary Se has shown various benefits, including enhanced growth performance, immune functions, and nutritional quality of meats, with reduced oxidative stress and inflammation, and finally enhanced thyroid health and fertility in humans. The emergence of nanoparticles presents a novel and innovative technology. Notably, Se in the form of nanoparticles (SeNPs) has lower toxicity, higher bioavailability, lower excretion in animals, and is linked to more powerful and superior biological activities (at a comparable Se dose) than traditional chemical forms of dietary Se. As a result, the development of tailored SeNPs for their use in intensive agriculture and as candidate for therapeutic drugs for human pathologies is now being actively explored. This review highlights the biological impacts of SeNPs on growth and reproductive performances, their role in modulating heat and oxidative stress and inflammation and the varying modes of synthesis of SeNPs.

Selenite-mediated production of superoxide radical anions in A549 cancer cells is accompanied by a selective increase in SOD1 concentration, enhanced apoptosis and Se–Cu bonding

Publisher: Springer Science and Business Media LLC

Date: 15-02-2014

DOI: 10.1007/S00775-014-1113-X

Abstract: Selenite may exert its cytotoxic effects against cancer cells via the generation of reactive oxygen species (ROS). We investigated sources of, and the cellular response to, superoxide radical anion (O2 (·-)) generated in human A549 lung cancer cells after treatment with selenite. A temporal delay was observed between selenite treatment and increases in O2 (·-) production and biomarkers of apoptosis/necrosis, indicating that the reduction of selenite by the glutathione reductase/NADPH system (yielding O2 (·-)) is a minor contributor to ROS production under these conditions. By contrast, mitochondrial and NADPH oxidase O2 (·-) generation were the major contributors. Treatment with a ROS scavenger [poly(ethylene glycol)-conjugated superoxide dismutase (SOD) or sodium 4,5-dihydroxybenzene-1,3-disulfonate] 20 h after the initial selenite treatment inhibited both ROS generation and apoptosis determined at 24 h. In addition, SOD1 was selectively upregulated and its perinuclear cytoplasmic distribution was colocalised with the cellular distribution of selenium. Interestingly, messenger RNA for manganese superoxide dismutase, catalase, inducible haem oxygenase 1 and glutathione peroxidase either remained unchanged or showed a delayed response to selenite treatment. Colocalisation of Cu and Se in these cells (Weekley et al. in J. Am. Chem. Soc. 133:18272-18279, 2011) potentially results from the formation of a Cu-Se species, as indicated by Cu K-edge extended X-ray absorption fine structure spectra. Overall, SOD1 is upregulated in response to selenite-mediated ROS generation, and this likely leads to an accumulation of toxic hydrogen peroxide that is temporally related to decreased cancer cell viability. Increased expression of SOD1 gene rotein coupled with formation of a Cu-Se species may explain the colocalisation of Cu and Se observed in these cells.

Reduction of Bridgehead Halogens by an Intramolecular Electron Transfer Radical Mechanism

Publisher: American Chemical Society (ACS)

Date: 09-1995

DOI: 10.1021/JO00122A030

NFkB Inhibition Mitigates Serum Amyloid A-Induced Pro-Atherogenic Responses in Endothelial Cells and Leukocyte Adhesion and Adverse Changes to Endothelium Function in Isolated Aorta

Publisher: MDPI AG

Date: 02-11-2018

DOI: 10.20944/PREPRINTS201810.0766.V1

Abstract: The acute phase protein serum amyloid A (SAA) is associated with endothelial dysfunction and early-stage atherogenesis. Stimulation of vascular cells with SAA increases gene expression of pro-inflammation cytokines and tissue factor (TF). Activation of the transcription factor, nuclear factor kappa-B (NFkB), may be central to SAA-mediated endothelial cell inflammation, dysfunction and pro-thrombotic responses, while targeting NFkB with a pharmacologic inhibitor, BAY11-7082, may mitigate SAA activity. Human carotid artery endothelial cells (HCtAEC) were pre-incubated (1.5 h) with 10 & micro M BAY11-7082 or vehicle (control) followed by SAA (10 & mu g/mL 4.5 h). Under these conditions gene expression for TF and TNF increased in SAA-treated HCtAEC and pre-treatment with BAY11-7082 significantly (TNF) and marginally (TF) reduced mRNA expression. Intracellular TNF and IL-6 protein also increased in HCtAEC supplemented with SAA and this expression was inhibited by BAY11-7082. Supplemented BAY11-7082 also significantly decreased SAA-mediated leukocyte adhesion to apolipoprotein E-deficient mouse aorta in ex vivo vascular flow studies. In vascular function studies, isolated aortic rings pre-treated with BAY11-7082 prior to incubation with SAA showed improved endothelium-dependent vasorelaxation and increased vascular cGMP content. Together these data suggest that inhibition of NFkB activation may protect endothelial function by inhibiting the pro-inflammatory and pro-thrombotic activities of SAA.

Substituent-Dependent nitration of 9-Substituted 9, 10-Dihydro-9, 10-ethanoanthracenes

Publisher: CSIRO Publishing

Date: 1995

DOI: 10.1071/CH9951949

Abstract: Mononitration of 9-substituted ethanoanthracenes, bearing Me, But, F, Br, I, OMe , NO2, CN, CHO or CO2Me substituents at the bridgehead carbon, was found to occur exclusively at the β-positions of the aromatic ring. The mononitro products were isolated, identified by 1H n.m.r. spectroscopy, and their relative proportions were estimated by quantitative g.l.c . and/or by 1H n.m.r. spectroscopy. For all the above substrates the proportion of nitration at the β-position meta to the bridgehead carbon bearing the substituent [to give compounds of the general form (4)] was greater than the proportion of nitration at the corresponding β-position para to the bridgehead substituent [to give compounds of the general form (3)]. Whilst the preferential nitration at the β-positions of the aromatic rings is consistent with the previously reported nitration of 9,10-dihydro-9,10-ethanoanthracene (2a) itself, no observations of this preferential meta attack have been made previously. No correlation could be made of this behaviour with available substituent parameters for the widely sterically and electronically disparate set of substituents used in this study, and the origin of this preferential attack remains unclear. Dinitration in this system was studied only superficially. The influence of the bridgehead substituent together with that of the nitro group already present on one aromatic ring appear to combine with quite unpredictable results in orienting the position of attack of the incoming nitro group onto the other (non-nitrated) aromatic ring.

Role of α-Tocopheroxyl Radical in the Initiation of Lipid Peroxidation in Human Low-Density Lipoprotein Exposed to Horse Radish Peroxidase

Publisher: American Chemical Society (ACS)

Date: 02-1997

DOI: 10.1021/BI962493J

A DNA Oligonucleotide−Hemin Complex Cleaves t-Butyl Hydroperoxide through a Homolytic Mechanism

Publisher: American Chemical Society (ACS)

Date: 11-08-2001

DOI: 10.1021/IC010025E

Abstract: Both electron paramagnetic resonance (EPR) and electronic absorption spectroscopy have been employed to investigate the reaction of a guanine-rich DNA nucleotide-hemin complex (PS2.M-hemin complex) and organic peroxide (t-Bu-OOH). Incubation of the PS2.M-hemin complex with t-Bu-OOH resulted in the time-dependent decrease in the heme Soret with concomitant changes to the visible bands of the electronic absorbance spectrum for the PS2.M-hemin complex. Parallel EPR studies using the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) combined with spectral simulation demonstrated the presence of tert-butyloxyl, carbon-centered methyl, and methyl peroxyl radicals as well as a simple nitroxide (triplet) signal. Experiments, performed by maintaining a constant ratio of t-Bu-OOH/PS2.M-hemin complex ( approximately 35 mol/mol) while varying DMPO concentration, indicated that the relative contributions of each radical adduct to the composite EPR spectrum were significantly influenced by the DMPO concentration. For ex le, at DMPO/PS2.M-hemin of 10-50 mol/mol, a complex mixture of radicals was consistently detected, whereas at high trapping efficiency (i.e., DMPO/PS2.M-hemin of approximately 250 mol/mol) the tert-butyloxyl-DMPO adduct was predominant. In contrast, at relatively low DMPO/PS2.M-hemin complex ratios of < or =5 mol/mol, a simple nitroxide three-line EPR signal was detected largely in the absence of all other radicals. Together, these data indicate that tert-butyloxyl radical is the primary radical likely formed from the homolytic cleavage of the O-O peroxy bond of t-Bu-OOH, while methyl and methyl peroxyl radicals result from beta-scission of the primary tert-butyloxyl radical product.

Pitfalls in the use of arachidonic acid oxidation products to assign lipoxygenase activity in cancer cells

Publisher: Informa UK Limited

Date: 2009

DOI: 10.1080/10715760903145013

Abstract: Arachidonic acid (AA) reaction with cyclooxygenase (COX) and lipoxygenases (LOX) yield eicosanoids that can mediate prostate cancer proliferation and enhance both tumour vascularization and metastasis. Increasingly measurement of eicosanoids with liquid chromatography is employed to implicate LOX activity in different biological systems and in particular link LOX activity to the progression of cancer in experimental models. This study demonstrates that simply identifying patterns of eicosanoid regio-isomerism is insufficient to designate LOX activity in prostate cancer cells and the analysis must include complete stereochemical assignment of the various isomers in order to validate the assignment of LOX activity.

Multiplex analysis of mass imaging data: Application to the pathology of experimental myocardial infarction

Publisher: Wiley

Date: 02-2022

DOI: 10.1111/APHA.13790

Abstract: Imaging mass cytometry (IMC) affords simultaneous immune‐labelling/imaging of multiple antigens in the same tissue. Methods utilizing multiplex data beyond co‐registration are lacking. This study developed and applied an innovative spatial analysis workflow for multiplex imaging data to IMC data determined from cardiac tissues and revealed the mechanism(s) of neutrophil‐mediated post‐myocardial‐infarction damage. IMC produced multiplex images with various redox/inflammatory markers. The cardiac peri‐infarct zone (PIZ) was determined to be up to 240 µm from the infarct border based on the presence of neutrophils. The tissue region beyond the infarct was defined as the remote area (RA). ImageJ was used to quantify the immunoreactivity. Functional assessments included infarct size, cell necro/apoptosis, total thiol assay and echocardiogram. Expression of damage markers decreased in order from the infarct area to PIZ and then RA, reflecting the neutrophil density in the regions. Concentrically spaced “shoreline contour analysis” around the cardiac infarct extending into the PIZ showed that immunoreactivity for damage markers decreased linearly with increasing distance from the infarct, concomitant with a decreasing neutrophil‐myeloperoxidase (MPO) gradient from the infarct to the PIZ. Stratifying by concentric bands around in idual MPO + ‐signal identified that the immunoreactivity of haem‐oxygenase‐1 (HO‐1) and phosphorylated‐p38 mitogen‐activated protein kinase (pP38) peaked near neutrophils. Furthermore, spatial dependence between neutrophils and markers of cardiac cellular damage was confirmed by nearest‐neighbour distance analysis. Post‐infarction tissue exhibited declined functional parameters that were associated with neutrophil migration from the infarct to PIZ. This image‐based quantitative protocol revealed the spatial association and provided potential molecular pathways responsible for neutrophil‐mediated damage post‐infarction.

Regio- and stereo-chemical oxidation of linoleic acid by human myoglobin and hydrogen peroxide: Tyr¹⁰³ affects rate and product distribution

Publisher: Portland Press Ltd.

Date: 06-07-2004

DOI: 10.1042/BJ20031924

Abstract: Mb (myoglobin) plus H2O2 catalyses the oxidation of various substrates via a peroxidase-like activity. A Y103F (Tyr103→Phe) variant of human Mb has been constructed to assess the effect of exchanging an electron-rich oxidizable amino acid on the peroxidase activity of human Mb. Steady-state analyses of reaction mixtures containing Y103F Mb, purified linoleic acid and H2O2 revealed a lower total yield of lipid oxidation products than mixtures containing the wild-type protein, consistent with the reported decrease in the rate constant for reaction of Y103F Mb with H2O2 [Witting, Mauk and Lay (2002) Biochemistry 41, 11495–11503]. Irrespective of the Mb employed, lipid oxidation yielded 9(R/S)-HODE [9(R,S)-hydroxy-10E,12Z-octadecadienoic acid] in preference to 13(R/S)-HODE [13(R,S)-hydroxy-9Z,11E-octadecadienoic acid], while 9- and 13-keto-octadecadienoic acid were formed in trace amounts. However, lipid oxidation by the Y103F variant of Mb proceeded with a lower Vmax value and an increased Km value relative to the wild-type control. Consistent with the increased Km, the product distribution from reactions with Y103F Mb showed decreased selectivity compared with the wild-type protein, as judged by the decreased yield of 9(S)-relative to 9(R)-HODE. Together, these data verify that Tyr103 plays a significant role in substrate binding and orientation in the haem pocket of human Mb. Also, the midpoint potential for the Fe(III)/(II) one-electron reduction was shifted slightly, but significantly, to a higher potential, confirming the importance of Tyr103 to the hydrogen-bonding network involving residues that line the haem crevice of human Mb.

Reaction of Human Myoglobin and Nitric Oxide

Publisher: Elsevier BV

Date: 02-2001

DOI: 10.1074/JBC.M005758200

Comparing the potential renal protective activity of desferrioxamine B and the novel chelator desferrioxamine B-N-(3-hydroxyadamant-1-yl)carboxamide in a cell model of myoglobinuria

Publisher: Portland Press Ltd.

Date: 13-04-2011

DOI: 10.1042/BJ20101728

Abstract: Accumulating Mb (myoglobin) in the kidney following severe burns promotes oxidative damage and inflammation, which leads to acute renal failure. The potential for haem–iron to induce oxidative damage has prompted testing of iron chelators [e.g. DFOB (desferrioxamine B)] as renal protective agents. We compared the ability of DFOB and a DFOB-derivative {DFOB-AdAOH [DFOB-N-(3-hydroxyadamant-1-yl)carboxamide]} to protect renal epithelial cells from Mb insult. Loading kidney-tubule epithelial cells with dihydrorhodamine-123 before exposure to 100 μM Mb increased rhodamine-123 fluorescence relative to controls (absence of Mb), indicating increased oxidative stress. Extracellular Mb elicited a reorganization of the transferrin receptor as assessed by monitoring labelled transferrin uptake with flow cytometry and inverted fluorescence microscopy. Mb stimulated HO-1 (haem oxygenase-1), TNFα (tumour necrosis factor α), and both ICAM (intercellular adhesion molecule) and VCAM (vascular cell adhesion molecule) gene expression and inhibited epithelial monolayer permeability. Pre-treatment with DFOB or DFOB-AdAOH decreased Mb-mediated rhodamine-123 fluorescence, HO-1, ICAM and TNFα gene expression and restored monolayer permeability. MCP-1 (monocyte chemotactic protein 1) secretion increased in cells exposed to Mb-insult and this was abrogated by DFOB or DFOB-AdAOH. Cells treated with DFOB or DFOB-AdAOH alone showed no change in permeability, MCP-1 secretion or HO-1, TNFα, ICAM or VCAM gene expression. Similarly to DFOB, incubation of DFOB-AdAOH with Mb plus H2O2 yielded nitroxide radicals as detected by EPR spectroscopy, indicating a potential antioxidant activity in addition to metal chelation Fe(III)-loaded DFOB-AdAOH showed no nitroxide radical formation. Overall, the chelators inhibited Mb-induced oxidative stress and inflammation and improved epithelial cell function. DFOB-AdAOH showed similar activity to DFOB, indicating that this novel low-toxicity chelator may protect the kidney after severe burns.

Inverse deuterium kinetic isotope effect for peroxidation in human low‐density lipoprotein (LDL): a simple test for tocopherol‐mediated peroxidation of LDL lipids

Publisher: Wiley

Date: 13-11-1995

DOI: 10.1016/0014-5793(95)01172-B

Abstract: alpha-Tocopherol (alpha-TOH) can act as a pro- or antioxidant for isolated ubiquinol-10-free human low density lipoprotein (LDL). We demonstrate that alpha-TOH is a more potent pro-oxidant than other forms of vitamin E for LDL peroxidation initiated by mild fluxes of aqueous peroxyl radicals and low concentrations of Cu2+. A simple deuterium exchange test shows that alpha-TOH switches from pro- to anti-oxidant at Cu2+:LDL ratios > 2.5. The results suggest that this test may be useful to distinguish 'inhibited' peroxidation of emulsion lipids propagated via the lipid peroxyl radical from that mediated via the antioxidant radical.

RETRACTION OF ARTICLE

Publisher: Bentham Science Publishers Ltd.

Date: 08-2010

DOI: 10.2174/092986710791859405

Oxidant stress and damage in post-ischemic mouse hearts: Effects of adenosine

Publisher: Springer Science and Business Media LLC

Date: 23-05-2006

DOI: 10.1007/S11010-005-9093-3

Abstract: Despite the general understanding that ischemia-reperfusion (I/R) promotes oxidant stress, specific contributions of oxidant stress or damage to myocardial I/R injury remain poorly defined. Moreover, whether endogenous 'cardioprotectants' such as adenosine act via limiting this oxidant injury is unclear. Herein we characterized effects of 20 min ischemia and 45 min reperfusion on cardiovascular function, oxidative stress and damage in isolated perfused mouse hearts (with glucose or pyruvate as substrate), and examined whether 10 microM adenosine modified these processes. In glucose-perfused hearts post-ischemic contractile function was markedly impaired (< 50% of pre-ischemia), cell damage assessed by lactate dehydrogenase (LDH) release was increased (12 +/- 2 IU/g vs. 0.2 +/- 0.1 IU/g in normoxic hearts), endothelial-dependent dilation in response to ADP was impaired while endothelial-independent dilation in response to nitroprusside was unaltered. Myocardial oxidative stress increased significantly, based on decreased glutathione redox status ([GSSG]/[GSG + GSSH] = 7.8 +/- 0.3% vs. 1.3 +/- 0.1% in normoxic hearts). Tissue cholesterol, native cholesteryl esters (CE) and the lipid-soluble antioxidant alpha-tocopherol (alpha-TOH, the most biologically active form of vitamin E) were unaffected by I/R, whereas markers of primary lipid peroxidation (CE-derived lipid hydroperoxides and hydroxides CE-O(O)H) increased significantly (14 +/- 2 vs. 2 +/- 1 pmol/mg in normoxic hearts). Myocardial alpha -tocopherylquinone (alpha-TQ an oxidation product of alpha -TOH) also increased (10.3 +/- 1.0 vs. 1.7 +/- 0.2 pmol/mg in normoxic hearts). Adenosine treatment improved functional recovery and vascular function, and limited LDH efflux. These effects were associated with an anti-oxidant effect of adenosine, as judged by inhibition of I/R-mediated changes in glutathione redox status (by 60%), alpha-TQ (80%) and CE-O(O)H (100%). Provision of 10 mM pyruvate as sole substrate (to by-pass glycolysis) modestly reduced I/R injury and changes in glutathione redox status and alpha-TQ, but not CE-O(O)H. Adenosine exerted further protection and anti-oxidant actions in these hearts. Functional recoveries and LDH efflux correlated inversely with oxidative stress and alpha -TQ (but not CE-O(O)H) levels. Collectively, our data reveal selective oxidative events in post-ischemic murine hearts, which are effectively limited by adenosine (independent of substrate). Correlation of post-ischemic cardiovascular outcomes with specific oxidative events (glutathione redox state, alpha-TQ) supports an important anti-oxidant component to adenosinergic protection.

Immunomodulatory effects of intestinal mesenchymal cells in the context of inflammatory bowel disease

Publisher: Wiley

Date: 04-08-2021

DOI: 10.1111/APHA.13721

Protective effects of probucol in two animal models of atherosclerosis

Publisher: Informa UK Limited

Date: 04-2000

DOI: 10.1179/135100000101535393

Efficacy of the Piperidine Nitroxide 4-MethoxyTEMPO in Ameliorating Serum Amyloid A-Mediated Vascular Inflammation

Publisher: MDPI AG

Date: 27-04-2021

DOI: 10.3390/IJMS22094549

Abstract: Intracellular redox imbalance in endothelial cells (EC) can lead to endothelial dysfunction, which underpins cardiovascular diseases (CVD). The acute phase serum amyloid A (SAA) elicits inflammation through stimulating production of reactive oxygen species (ROS). The cyclic nitroxide 4-MethoxyTEMPO (4-MetT) is a superoxide dismutase mimetic that suppresses oxidant formation and inflammation. The aim of this study was to investigate whether 4-MetT inhibits SAA-mediated activation of cultured primary human aortic EC (HAEC). Co-incubating cells with 4-MetT inhibited SAA-mediated increases in adhesion molecules (VCAM-1, ICAM-1, E-selectin, and JAM-C). Pre-treatment of cells with 4-MetT mitigated SAA-mediated increases in transcriptionally activated NF-κB-p65 and P120 Catenin (a stabilizer of Cadherin expression). Mitochondrial respiration and ROS generation (mtROS) were adversely affected by SAA with decreased respiratory reserve capacity, elevated maximal respiration and proton leakage all characteristic of SAA-treated HAEC. This altered respiration manifested as a loss of mitochondrial membrane potential (confirmed by a decrease in TMRM fluorescence), and increased mtROS production as assessed with MitoSox Red. These SAA-linked impacts on mitochondria were mitigated by 4-MetT resulting in restoration of HAEC nitric oxide bioavailability as confirmed by assessing cyclic guanosine monophosphate (cGMP) levels. Thus, 4-MetT ameliorates SAA-mediated endothelial dysfunction through normalising EC redox homeostasis. Subject to further validation in in vivo settings these outcomes suggest its potential as a therapeutic in the setting of cardiovascular pathologies where elevated SAA and endothelial dysfunction is linked to enhanced CVD.

Oxidative stress in Alzheimer's disease: Primary villain or physiological by-product?

Publisher: Informa UK Limited

Date: 07-2013

DOI: 10.1179/1351000213Y.0000000052

Endogenous Adenosine Selectively Modulates Oxidant Stressviathe A₁Receptor in Ischemic Hearts

Publisher: Mary Ann Liebert Inc

Date: 11-2009

DOI: 10.1089/ARS.2009.2644

Investigation of indoleamine 2,3-dioxygenase using synchrotron radiation techniques

Publisher: Elsevier BV

Date: 07-2003

DOI: 10.1016/S0162-0134(03)80546-9

Site-specific hypochlorous acid-induced oxidation of recombinant human myoglobin affects specific amino acid residues and the rate of cytochrome b5-mediated heme reduction

Publisher: Elsevier BV

Date: 2010

DOI: 10.1016/J.FREERADBIOMED.2009.09.023

Abstract: Myeloperoxidase catalyzes the reaction of chloride ions with H(2)O(2) to yield hypochlorous acid (HOCl), which can damage proteins. Human myoglobin (HMb) differs from other Mbs by the presence of a cysteine residue at position 110 (Cys110). This study has (i) compared wild-type and a Cys110Ala variant of HMb to assess the influence of Cys110 on HOCl-induced amino acid modification and (ii) determined whether HOCl oxidation of HMb affects the rate of ferric heme reduction by cytochrome b(5). For wild-type HMb (HOCl:Mb ratio of 5:1 mol:mol), Cys110 was preferentially oxidized to a homodimeric or cysteic acid product-sulfenic/sulfinic acids were not detected. At a HOCl:Mb ratio 10:1 mol:mol, methionine (Met) oxidation was detected, and this was enhanced in the Cys110Ala variant. Tryptophan (Trp) oxidation was detected only in the Cys110Ala variant at the highest HOCl dose tested, with oxidation susceptibility following the order Cys>Met>Trp. Tyrosine chlorination was evident only in reactions between HOCl and the Cys110Ala variant and at a longer incubation time (24 h), consistent with the formation via chlorine-transfer reactions from preformed chloramines. HOCl-mediated oxidation of wild-type HMb resulted in a dose-dependent decrease in the observed rate constant for ferric heme reduction (approx two-fold at HOCl:Mb of 10:1 mol:mol). These data indicate that Cys110 influences the oxidation of HMb by HOCl and that oxidation of Cys, Met, and Trp residues is associated with a decrease in the one-electron reduction of ferric HMb by other proteins such heme-Fe(3+) reduction is critical to the maintenance of function as an oxygen storage protein in tissues.

Targeting of cytosolic phospholipase A2a impedes cell cycle re-entry of quiescent prostate cancer cells

Publisher: Impact Journals, LLC

Date: 24-09-2015

DOI: 10.18632/ONCOTARGET.5277

Evidence supporting oxidative stress in a moderately affected area of the brain in Alzheimer’s disease

Publisher: Springer Science and Business Media LLC

Date: 08-2018

DOI: 10.1038/S41598-018-29770-3

Abstract: The pathogenesis of Alzheimer’s disease (AD) remains to be elucidated. Oxidative damage and excessive beta-amyloid oligomers are components of disease progression but it is unclear how these factors are temporally related. At post mortem, the superior temporal gyrus (STG) of AD cases contains plaques, but displays few tangles and only moderate neuronal loss. The STG at post mortem may represent a brain region that is in the early stages of AD or alternately a region resistant to AD pathogenesis. We evaluated expression profiles and activity of endogenous anti-oxidants, oxidative damage and caspase activity in the STG of apolipoprotein ε4-matched human AD cases and controls. Total superoxide dismutase (SOD) activity was increased, whereas total glutathione peroxidase (GPX), catalase (CAT) and peroxiredoxin (Prx) activities, were decreased in the AD-STG, suggesting that hydrogen peroxide accumulates in this brain region. Transcripts of the transcription factor NFE2L2 and inducible HMOX1 , were also increased in the AD-STG, and this corresponded to increased Nuclear factor erythroid 2-related factor (NRF-2) and total heme-oxygenase (HO) activity. The protein oxidation marker 4-hydroxynonenal (4-HNE), remained unchanged in the AD-STG. Similarly, caspase activity was unaltered, suggesting that subtle redox imbalances in early to moderate stages of AD do not impact STG viability.

Nitric oxide stimulates myoglobin gene and protein expression in vascular smooth muscle

Publisher: Portland Press Ltd.

Date: 25-09-2009

DOI: 10.1042/BJ20090716

Abstract: Mb (myoglobin) is a haemoprotein present in cardiac, skeletal and smooth muscle and is primarily responsible for the storage and ‘facilitated transfer’ of molecular oxygen from the cell membrane to mitochondria. Also, Mb plays a role in regulating •NO (nitric oxide) homoeostasis through (i) binding •NO (Mb–NO complex) (ii) oxidation of •NO to nitrate and (iii) formation of vasoactive S-nitroso-Mb [Rayner, B.S., Wu, B.-J., Raftery, M., Stocker, R. and Witting, P.K. (2005) J. Biol. Chem. 280, 9985–9993]. Pathological •NO concentrations affect mitochondrial function and decrease cell viability through inducing apoptosis. Treatment of cultured rat VSMCs (vascular smooth muscle cells) with cumulative doses (0.1, 1 or 10 μM) of •NO from the donors diethylamineNONOate or spermineNONOate (N-[2-aminoethyl]-N-[2-hydroxy-3-nitrosohydrazine]-1,2-ethelenediamine) yielded a time-dependent increase in Mb gene expression. Concomitant transcriptional activation increased the concentration of Mb within cultured rat or primary human VSMCs as judged by Western blot analysis and indirect immunofluorescence microscopy. Cell viability did not decrease in these cells at the •NO doses tested. Importantly, sub-culturing isolated rat aortic segments for 7 days in the presence of L-arginine at 37 °C stimulated •NO production with a parallel increase in Mb in the underlying VSMCs. Overall, exposure of VSMCs (either in cell culture or intact vessels) to pathological •NO promotes an up-regulation of the Mb gene and protein, suggesting a feedback relationship between •NO and Mb that regulates the concentration of the potent cell signalling molecule in the vessel wall, similar to the role haemoglobin plays in the vessel lumen.

Comparison of the effects of α-tocopherol, ubiquinone-10 and probucol at therapeutic doses on atherosclerosis in WHHL rabbits

Publisher: Elsevier BV

Date: 08-2002

DOI: 10.1016/S0021-9150(02)00023-0

Abstract: Oxidative modification of lipoproteins may trigger and maintain atherogenesis. We compared the effects of different antioxidants (alpha-tocopherol, probucol, ubiquinone-10) at doses similar to those used in humans in Watanabe Heritable Hyperlipidemic (WHHL) rabbits for 12 months. Aortic lesions were analyzed for their extent and cellular composition of lesions, mean thickness of fibrous caps and density of smooth muscle cells therein, content of antioxidants, non-oxidized and oxidized lipids. Compared to controls, probucol significantly lowered the extent and macrophage content of lesions and increased the existence and smooth muscle cell density of fibrous caps. alpha-Tocopherol supplementation increased the aortic content of vitamin E, but had no decreasing effect on either the accumulation of macrophage-specific antigen in the aorta or lesion size. Nevertheless, both probucol and alpha-tocopherol significantly decreased in vitro LDL oxidizability, measured under typically strong oxidative conditions. Ubiquinone-10 supplement increased lesion size and the fraction of lesions containing fibrous caps however, LDL oxidizability remained unaffected by ubiquinone-10 treatment. None of the antioxidants tested lowered oxidized lipids within aortic tissue however, long-term treatment with probucol provided the most effective anti-atherosclerotic effect, while alpha-tocopherol may be pro-atherogenic and ubiquinone-10 exerts ambivalent effects. Our data suggest that (i) widely used oxidation measures, such as ex-vivo LDL oxidizability, do not reflect the degree of atherosclerosis and (ii) long-term beneficial effects of relatively low doses of antioxidants may be outweighed by high levels of plasma cholesterol in WHHL rabbits.

Dissociation of atherogenesis from aortic accumulation of lipid hydro(pero)xides in Watanabe heritable hyperlipidemic rabbits

Publisher: American Society for Clinical Investigation

Date: 15-07-1999

DOI: 10.1172/JCI6391

Determination of spread of injectate after ultrasound-guided transversus abdominis plane block: a cadaveric study

Publisher: Elsevier BV

Date: 2009

DOI: 10.1093/BJA/AEN344

Abstract: The transversus abdominis plane (TAP) block is a new regional anaesthesia technique that provides analgesia after abdominal surgery. It involves injection of local anaesthetic into the plane between the transversus abdominis and the internal oblique muscles. The TAP block can be performed using a landmark technique through the lumbar triangle or with ultrasound guidance. The goal of this anatomical study with dye injection into the TAP and subsequent cadaver dissections was to establish the likely spread of local anaesthesia in vivo and the segmental nerve involvement resulting from ultrasound-guided TAP block. An ultrasound-guided injection of aniline dye into the TAP was performed for each hemi-abdominal wall of 10 unembalmed human cadavers and this was followed by dissection to determine the extent of dye spread and nerve involvement in the dye injection. After excluding one pilot specimen and one with advanced tissue decomposition, 16 hemi-abdominal walls were successfully injected and dissected. The lower thoracic nerves (T10-T12) and first lumbar nerve (L1) were found emerging from posterior to anterior between the costal margin and the iliac crest. Segmental nerves T10, T11, T12, and L1 were involved in the dye in 50%, 100%, 100%, and 93% of cases, respectively. This anatomical study shows that an ultrasound-guided TAP injection cephalad to the iliac crest is likely to involve the T10-L1 nerve roots, and implies that the technique may be limited to use in lower abdominal surgery.

Mitochondria transmit apoptosis signalling in cardiomyocyte-like cells and isolated hearts exposed to experimental ischemia-reperfusion injury

Publisher: Informa UK Limited

Date: 06-2007

DOI: 10.1179/135100007X200227

Oxidation of Free Fatty Acids in Low Density Lipoprotein by 15-Lipoxygenase Stimulates Nonenzymic, α-Tocopherol-mediated Peroxidation of Cholesteryl Esters

Publisher: Elsevier BV

Date: 11-1997

DOI: 10.1074/JBC.272.48.30067

Molecular changes to the rat renal cotransporters PEPT1 and PEPT2 due to ageing

Publisher: Springer Science and Business Media LLC

Date: 17-07-2019

DOI: 10.1007/S11010-018-3413-X

Abstract: Renal PEPT1 and PEPT2 cotransporters play an important role in the balance of circulating body oligopeptides and selected peptidomimetic drugs. We aim to comprehensively characterise age-related changes of the renal PEPT cotransporters at the gene, protein, and functional level. Brush border membrane vesicles (BBMV) and outer medulla membrane vesicles (OMMV) were isolated from the kidneys of young, middle-aged and old rats. The protein expression of PEPT1 was not only increased in BBMV from old rats, but PEPT1 also appeared in OMMV from middle-aged and old rats. SLC15A1 gene expression in the renal cortex increased in middle-aged group. PEPT2 protein expression was not only increased with ageing, but PEPT2 also was found in BBMV from middle-aged and old groups. SLC15A2 gene expression in the renal outer medulla increased in the old group. These changes in the expressions and localisations of PEPT1 and PEPT2 could explain the changes to transport activity in BBMV and OMMV. These findings provide novel insights that would be useful for maintaining protein nutrition and optimising the delivery of some peptidomimetic drugs in elderly in iduals.

Lack of the antioxidant glutathione peroxidase-1 does not increase atherosclerosis in C57BL/J6 mice fed a high-fat diet

Publisher: Elsevier BV

Date: 06-2006

DOI: 10.1194/JLR.M500377-JLR200

Reaction of Human Myoglobin and Peroxynitrite: Characterizing Biomarkers for Myoglobin-Derived Oxidative Stress

Publisher: Elsevier BV

Date: 08-2001

DOI: 10.1006/BBRC.2001.5397

The acute-phase protein serum amyloid A induces endothelial dysfunction that is inhibited by high-density lipoprotein

Publisher: Elsevier BV

Date: 10-2011

DOI: 10.1016/J.FREERADBIOMED.2011.06.031

Abstract: The acute-phase protein serum amyloid A (SAA) is elevated during inflammation and may be deposited in atheroma where it promotes atherosclerosis. We investigated the proatherogenic effects of SAA on the vascular endothelium and their regulation by high-density lipoprotein (HDL). Exposure of human aortic endothelial cells (HAEC) to SAA (0.25-25μg/ml) decreased nitric oxide ((•)NO) synthesis/bioavailability, although the endothelial NO synthase monomer-to-dimer ratio was unaffected. SAA (10μg/ml) stimulated a Ca(2+) influx linked to apocynin-sensitive superoxide radical anion (O(2)(•-)) production. Gene expression for arginase-1, nuclear factor κB (NF-κB), interleukin-8, and tissue factor (TF) increased within 4h of SAA stimulation. Enzymatically active Arg-1/2 was detected in HAEC cultured with SAA for 24h. Therefore, in addition to modulating (•)NO bioavailability by stimulating O(2)(•-) production in the endothelium, SAA modulated vascular l-Arg bioavailability. SAA also diminished relaxation of preconstricted aortic rings induced by acetylcholine, and added superoxide dismutase restored the vascular response. Preincubation of HAEC with HDL (100 or 200, but not 50, μg/ml) before (not after) SAA treatment ameliorated the Ca(2+) influx and O(2)(•-) production decreased TF, NF-κB, and Arg-1 gene expression and preserved overall vascular function. Thus, SAA may promote endothelial dysfunction by modulating (•)NO and l-Arg bioavailability, and HDL pretreatment may be protective. The relative HDL to SAA concentrations may regulate the proatherogenic properties of SAA on the vascular endothelium.

Mitochondria Play a Central Role in Apoptosis Induced by α-Tocopheryl Succinate, an Agent with Antineoplastic Activity:  Comparison with Receptor-Mediated Pro-Apoptotic Signaling

Publisher: American Chemical Society (ACS)

Date: 22-03-2003

DOI: 10.1021/BI020527J

Abstract: alpha-Tocopheryl succinate (alpha-TOS) is a semisynthetic vitamin E analogue with high pro-apoptotic and anti-neoplastic activity [Weber, T et al. (2002) Clin. Cancer Res. 8, 863-869]. Previous studies suggested that it acts through destabilization of subcellular organelles, including mitochondria, but compelling evidence is missing. Cells treated with alpha-TOS showed altered mitochondrial structure, generation of free radicals, activation of the sphingomyelin cycle, relocalization of cytochrome c and Smac/Diablo, and activation of multiple caspases. A pan-caspase inhibitor suppressed caspase-3 and -6 activation and phosphatidyl serine externalization, but not decrease of mitochondrial membrane potential or generation of radicals. For alpha-TOS, but not Fas or TRAIL, apoptosis was suppressed by caspase-9 inhibition, while TRAIL- and Fas-resistant cells overexpressing cFLIP or CrmA were susceptible to alpha-TOS. The central role of mitochondria was confirmed by resistance of mtDNA-deficient cells to alpha-TOS, by regulation of alpha-TOS apoptosis by Bcl-2 family members, and by anti-apoptotic activity of mitochondrially targeted radical scavengers. Co-treatment with alpha-TOS and anti-Fas IgM showed their cooperative effect, probably by signaling via different, convergent pathways. These data provide an insight into the molecular mechanism, by which alpha-TOS kills malignant cells, and advocate its testing as a potential anticancer agent or adjuvant.

Therapeutic inflammatory monocyte modulation using immune-modifying microparticles.

Publisher: American Association for the Advancement of Science (AAAS)

Date: 15-01-2014

DOI: 10.1126/SCITRANSLMED.3007563

Abstract: Negatively charged immune-modifying microparticles bind to the scavenger receptor MARCO on inflammatory monocytes, resulting in their apoptosis and reduced inflammatory damage in a range of diseases.

3-Hydroxyanthranilic acid is an efficient, cell-derived co-antioxidant for α-tocopherol, inhibiting human low density lipoprotein and plasma lipid peroxidation

Publisher: Elsevier BV

Date: 12-1996

DOI: 10.1074/JBC.271.51.32714

Secretory Phospholipase A₂ and Lipoprotein Lipase Enhance 15-Lipoxygenase-Induced Enzymic and Nonenzymic Lipid Peroxidation in Low-Density Lipoproteins^†

Publisher: American Chemical Society (ACS)

Date: 29-05-1998

DOI: 10.1021/BI9730745

Glutathione Enhances Antibiotic Efficiency and Effectiveness of DNase I in Disrupting Pseudomonas aeruginosa Biofilms While Also Inhibiting Pyocyanin Activity, Thus Facilitating Restoration of Cell En

Publisher: Frontiers Media SA

Date: 14-12-2017

DOI: 10.3389/FMICB.2017.02429

A role for acute-phase serum amyloid A and high-density lipoprotein in oxidative stress, endothelial dysfunction and atherosclerosis

Publisher: Informa UK Limited

Date: 10-2009

DOI: 10.1179/135100009X12525712409490

Oxidative stress in myocardial ischaemia reperfusion injury: a renewed focus on a long-standing area of heart research

Publisher: Informa UK Limited

Date: 08-2005

DOI: 10.1179/135100005X57391

Is there potential for antioxidants to enhance thrombolysis therapy in patients with ischemic stroke?

Publisher: Future Medicine Ltd

Date: 11-2006

DOI: 10.2217/14796678.2.6.659

Abstract: The medical and socio–economic burden of ischemic stroke is vast. Current thrombolytic therapies have a time-limited therapeutic window and do not provide significant benefits beyond tissue reperfusion. The detrimental effect of oxidative stress caused by excessive oxidant production due to cerebral reperfusion injury is a neglected consequence of ischemic stroke and warrants special consideration. Strategies directed at preventing or reducing oxidative damage in the brain post-ischemic stroke have the potential to improve neurological outcome and reduce morbidity and mortality from this common disease. Significantly, the prospect of increasing the size of the treatment window for thrombolytic therapies, perhaps by synergistic effects with other medications given in parallel, is also an avenue worthy of further investigation. This perspective outlines the current status of thrombolytic therapy for the treatment of ischemic stroke and explores the possibility of improving and expanding this potential therapy. Furthermore, the implications of directly treating damage caused by oxidative stress with novel antioxidant therapy are discussed.

Injury-induced reorganization in adult auditory cortex and its perceptual consequences

Publisher: Elsevier BV

Date: 09-2000

DOI: 10.1016/S0378-5955(00)00131-3

Abstract: Restricted cochlear lesions in adult animals result in a reorganization of auditory cortex such that the cortical region deprived of its normal input by the lesion is occupied by expanded representations of adjacent cochlear loci, and thus of the frequencies represented at those loci. Analogous injury-induced reorganization is seen in somatosensory, visual and motor cortices of adult animals after restricted peripheral lesions. The occurrence of such reorganization in a wide range of species (including simian primates), and across different sensory systems and forms of peripheral lesion, suggests that it would also occur in humans with similar lesions. Direct evidence in support of this suggestion is provided by a small body of functional imaging evidence in the somatosensory and auditory systems. Although such reorganization does not seem to have a compensatory function, such a profound change in the pattern of cortical activation produced by stimuli exciting peri-lesion parts of the receptor epithelium would be expected to have perceptual consequences. However, there is only limited psychophysical evidence for perceptual effects that might be attributable to injury-induced cortical reorganization, and very little direct evidence for the correlation between the perceptual phenomena and the occurrence of reorganization.

Reaction of Human Myoglobin and H2O2

Publisher: Elsevier BV

Date: 05-2001

DOI: 10.1074/JBC.M011707200

Oxidation of high density lipoproteins. I. Formation of methionine sulfoxide in apolipoproteins AI and AII is an early event that accompanies lipid peroxidation and can be enhanced by alpha-tocopherol.

Publisher: Elsevier BV

Date: 03-1998

DOI: 10.1074/JBC.273.11.6080

Oxidants and antioxidants in atherosclerosis

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 08-2001

DOI: 10.1097/00041433-200108000-00007

Abstract: The oxidative theory suggests that LDL oxidation contributes to atherogenesis, implying that attenuation of this process by antioxidants should decrease atherosclerosis. However, a causative link between LDL oxidation and atherogenesis is not firmly established. It requires the identification of the oxidants that are responsible for the initiation of LDL oxidation, and an understanding of the modified moieties that are responsible for the proatherogenic activities of oxidized LDL. The present review summarizes recent data on potential biological oxidants for LDL in the vessel wall, and discusses the antiatherogenic role(s) of selected antioxidants.

Metabolism of Selenite in Human Lung Cancer Cells: X-Ray Absorption and Fluorescence Studies

Publisher: American Chemical Society (ACS)

Date: 20-10-2011

DOI: 10.1021/JA206203C

Neutrophil Extracellular Trap Density Increases With Increasing Histopathological Severity of Crohn’s Disease

Publisher: Oxford University Press (OUP)

Date: 11-2021

DOI: 10.1093/IBD/IZAB239

Abstract: Intestinal neutrophil recruitment is a characteristic feature of the earliest stages of inflammatory bowel disease (IBD). Neutrophil elastase (NE) and myeloperoxidase (MPO) mediate the formation of neutrophil extracellular traps (NETs) NETs produce the bactericidal oxidant hypochlorous acid (HOCl), causing host tissue damage when unregulated. The project aim was to investigate the relationship between NET formation and clinical IBD in humans. Human intestinal biopsies were collected from Crohn’s disease (CD) patients, endoscopically categorized as unaffected, transitional, or diseased, and assigned a histopathological score. A significant linear correlation was identified between pathological score and cell viability (TUNEL+). Immunohistochemical analysis revealed the presence of NET markers NE, MPO, and citrullinated histone (CitH3) that increased significantly with increasing histopathological score. Diseased specimens showed greater MPO+-immunostaining than control (P & .0001) and unaffected CD (P & .0001), with transitional CD specimens also showing greater staining than controls (P & .05) and unaffected CD (P & .05). Similarly, NE+-immunostaining was elevated significantly in diseased CD than controls (P & .0001) and unaffected CD (P & .0001) and was significantly higher in transitional CD than in controls (P & .0001) and unaffected CD (P & .0001). The CitH3+-immunostaining of diseased CD was significantly higher than controls (P & .05), unaffected CD (P & .0001) and transitional CD (P & .05), with transitional CD specimens showing greater staining than unaffected CD (P & .01). Multiplex immunohistochemistry with z-stacking revealed colocalization of NE, MPO, CitH3, and DAPI (cell nuclei), confirming the NET assignment. These data indicate an association between increased NET formation and CD severity, potentially due to excessive MPO-mediated HOCl production in the extracellular domain, causing host tissue damage that exacerbates CD.

Chemical regulation of nitric oxide: a role for intracellular myoglobin?

Publisher: Informa UK Limited

Date: 06-2002

DOI: 10.1179/135100002125000361

Abstract: The detailed chemistry of nitric oxide (*NO) and regulation of this potent signal molecule through interactions with cellular components are complex and not clearly understood. In the vasculature, *NO plays a crucial role in vessel dilation by activating soluble guanylyl cyclase (sGC) in vascular smooth muscle cells (VSMC). *NO is responsible for maintaining coronary blood flow and normal cardiac function. However, *NO is a highly reactive molecule and this reactivity toward a range of alternate substrates may interfere with the activation of its preferred molecular target within VSMC. Interestingly, marked changes to *NO homeostasis are linked to disease progression. Thus, the physiological concentration of *NO is carefully regulated. Myoglobin is a haem-containing protein that is present in relatively high concentration in cardiac and skeletal muscle. Recently, the presence of myoglobin has been confirmed in human smooth muscle. The role of intracellular myoglobin is generally accepted as that of a passive di-oxygen storage protein. However, oxygenated myoglobin readily reacts with *NO to yield higher order N-oxides such as nitrate, while both the ferrous and ferric forms of the protein form a stable complex with *NO. Together, these two reactions effectively eliminate *NO on the physiological time-scale and strongly support the idea that myoglobin plays a role in maintaining *NO homeostasis in tissues that contain the protein. Interestingly, human myoglobin contains a sulfhydryl group and forms an S-nitroso-adduct similar to haemoglobin. In this article we discuss the potential for human myoglobin to actively participate in the regulation of *NO by three distinct mechanisms, namely oxidation, ligand binding, and through formation of biologically active S-nitroso-myoglobin.

Oxidation of high density lipoproteins. II. Evidence for direct reduction of lipid hydroperoxides by methionine residues of apolipoproteins AI and AII

Publisher: Elsevier BV

Date: 03-1998

DOI: 10.1074/JBC.273.11.6088

Myeloperoxidase in the inflamed colon: A novel target for treating inflammatory bowel disease

Publisher: Elsevier BV

Date: 05-2018

DOI: 10.1016/J.ABB.2018.03.012

Abstract: Inflammatory bowel disease (IBD) is a debilitating disorder involving inflammation of the gastrointestinal tract. The incidence of IBD is increasing worldwide. Immunological responses in the gastrointestinal (GI) tract to altered gut microbiota, mucosal injury and loss of intestinal epithelial cell function all contribute to a complex mechanism underlying IBD pathogenesis. Immune cell infiltration, particularly neutrophils, is a histological feature of IBD. This innate immune response is aimed at resolving intestinal damage however, neutrophils and monocytes that are recruited and accumulate in the GI wall, participate in IBD pathogenesis by producing inflammatory cytokines and soluble mediators such as reactive oxygen species (ROS one- and two-electron oxidants). Unregulated ROS production in host tissue is linked to oxidative damage and inflammation and may potentiate mucosal injury. Neutrophil-myeloperoxidase (MPO) is an abundant granule enzyme that catalyses production of potent ROS biomarkers of oxidative damage (and MPO protein) are increased in the mucosa of patients with IBD. Targeting MPO may mitigate oxidative damage to host tissue and ensuing inflammation. Here we identify mechanisms by which MPO activity perpetuates inflammation and contributes to host-tissue injury in patients with IBD and discuss MPO as a potential therapeutic target to protect the colon from inflammatory injury.

Inhibition of copper- and peroxyl radical-induced LDL lipid oxidation by ebselen: antioxidant actions in addition to hydroperoxide-reducing activity

Publisher: Elsevier BV

Date: 09-1996

DOI: 10.1016/0005-2760(96)00088-4

Abstract: The effects of ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one) on human LDL lipid oxidation induced by different fluxes of aqueous peroxyl radicals and cupric ion (at a Cu2+:LDL ratio of 17:1) were investigated. Addition of ebselen to LDL oxidised with Cu2+ prolonged the duration of the lag-phase typical for this oxidising condition, with the increase being proportional to the square of the ebselen concentration. Ebselen also prevented the formation of lipid hydroperoxides and inhibited the consumption of endogenous antioxidants during the early period of Cu(2+)-induced oxidation, during which time the drug was converted stoichiometrically into ebselen oxide (2-phenyl-1,2-benzisoselenazol-3(2H)-one-Se-oxide). Ebselen oxide itself was antioxidant inactive. Ebselen also inhibited formation of lipid-hydroperoxides and spared alpha-tocopherol during the initial stages of LDL oxidation mediated by low-flux of aqueous peroxyl radicals, where a lag-phase was not observed. When a higher flux of aqueous peroxyl radicals was used, ebselen increased the observed inhibited phase of peroxidation in a dose-dependent manner, though less pronounced than its prolongating effect on the lag-phase of Cu(2+)-induced LDL lipid oxidation. Ebselen was also able to directly interact with Cu1+, alkyl peroxyl radicals and alpha-tocopheroxyl radicals, demonstrating that the drug has a number of potential antioxidant activities in addition to its well-known hydroperoxide-reducing activity. We conclude that the antioxidant activities of ebselen are complex and that their relative importance likely vary depending on the experimental system used.

Serum amyloid A may potentiate prothrombotic and proinflammatory events in acute coronary syndromes

Publisher: Elsevier BV

Date: 02-2009

DOI: 10.1016/J.ATHEROSCLEROSIS.2008.04.049

Abstract: Elevated serum amyloid A (SAA) levels, like C-reactive protein (CRP), predict coronary events. Both induce monocyte tissue factor (TF), and peripheral blood mononuclear cells (PBMC) from patients with coronary artery disease (CAD) express higher TF in response to CRP. This study examined SAA induction of TF and tumour necrosis factor-alpha (TNF) in PBMC from patients with CAD and in monocytoid THP-1 cells. PBMC from 26 males with CAD (15 stable angina, SA, and 11 acute coronary syndromes, ACS) and 14 male controls were stimulated with SAA. SAA promoted up to six-fold increase in TF activity (recalcification assay) on PBMC from patients, associated with elevated TF mRNA and protein. PBMC responded optimally when monocytes were adherent. Unlike CRP, SAA induced TF and TNF in THP-1 cells. SAA-induced TNF was dose-dependently inhibited by HDL. PBMC from patients with ACS expressed more basal TF (257.4+/-46.8 mU/10(6) PBMC vs. 131.0+/-12.5 mU/10(6) PBMC, P=0.003), and greater SAA-induced TF than cells from controls, whereas no difference was found between SA and controls (ACS 2246+/-493, SA 1364+/-206, controls 1091+/-113 mU/10(6) PBMC, with SAA 250 ng/mL, P=0.002 ACS vs. controls across the dose range). Importantly, SAA-induced TNF levels (ELISA) were much higher in patients with ACS than SA or controls (ACS 211+/-41, SA 108+/-16, controls 73+/-11 pg/mL, with SAA 250 ng/mL, P=0.001 ACS vs. controls or P=0.013 ACS vs. SA across the dose range). SAA-induced TF and TNF correlated positively with serum SAA levels in CAD, but not controls. SAA is a prothrombotic and proinflammatory mediator in ACS which may contribute to atherogenesis and its complications.

Response to Low-density Granulocytes as Novel Biomarkers of Disease Activity in IBD

Publisher: Oxford University Press (OUP)

Date: 08-2023

DOI: 10.1093/IBD/IZAD133

Multiple protective activities of neuroglobin in cultured neuronal cells exposed to hypoxia re-oxygenation injury

Publisher: Wiley

Date: 09-02-2009

DOI: 10.1111/J.1471-4159.2008.05846.X

Abstract: Oxidative stress is associated with the pathology of acute and chronic neurodegenerative disease. We have cloned a human neuroglobin (Nb) construct and over-expressed this protein in cultured human neuronal cells to assess whether Nb ameliorates the cellular response to experimental hypoxia-reoxygenation (H/R) injury. Parental cells transfected with a blank (pDEST40) vector responded to H/R injury with a significant decrease in cellular ATP at 5 and 24 h after insult. This was coupled with increases in the cytosolic Ca(2+), and the transition metals iron (Fe), copper (Cu), and zinc (Zn) within the cell body, as monitored simultaneously using X-ray fluorescence microprobe imaging. Parental cell viability decreased over the same time period with a approximately 4 to 5-fold increase in cell death (maximum approximately 25%) matched by an increase in caspase 3/7 activation (peaking at a 15-fold increase after 24 h) and condensation of beta-actin along axonal processes. Over-expression of Nb inhibited ATP loss and except for significant decreases in the sulfur (S), chlorine (Cl), potassium (K) and Ca(2+) contents, maintained cellular ion homeostasis after H/R insult. This resulted in increased cell viability, significantly diminished caspase activation and maintenance of the beta-actin cytoskeletal structure and receptor-mediated endocytosis. These data indicate that bolstering the cellular content of Nb inhibits neuronal cell dysfunction promoted by H/R insult through multiple protective actions including: (i) maintenance of cellular bioenergetics (ii) inhibition of Ca(2+) influx (iii) a reduction in cellular uptake of Fe, Cu and Zn at the expense of S, Cl and K and (iv) an enhancement of cell viability through inhibiting necrosis and apoptosis.

The smoking-Associated oxidant hypothiocyanous acid induces endothelial nitric oxide synthase dysfunction

Publisher: Portland Press Ltd.

Date: 10-12-2014

DOI: 10.1042/BJ20131135

Abstract: Smokers have an elevated risk of cardiovascular disease but the origin(s) of this increased risk are incompletely defined. Considerable evidence supports an accumulation of the oxidant-generating enzyme MPO (myeloperoxidase) in the inflamed artery wall, and smokers have high levels of SCN−, a preferred MPO substrate, with this resulting in HOSCN (hypothiocyanous acid) formation. We hypothesized that this thiol-specific oxidant may target the Zn2+–thiol cluster of eNOS (endothelial nitric oxide synthase), resulting in enzyme dysfunction and reduced formation of the critical signalling molecule NO•. Decreased NO• bioavailability is an early and critical event in atherogenesis, and HOSCN-mediated damage to eNOS may contribute to smoking-associated disease. In the present study it is shown that exposure of isolated eNOS to HOSCN or MPO/H2O2/SCN− decreased active dimeric eNOS levels, and increased inactive monomer and Zn2+ release, compared with controls, HOCl (hypochlorous acid)- or MPO/H2O2/Cl−-treated s les. eNOS activity was increasingly compromised by MPO/H2O2/Cl− with increasing SCN− concentrations. Exposure of HCAEC (human coronary artery endothelial cell) lysates to pre-formed HOSCN, or MPO/H2O2/Cl− with increasing SCN−, increased eNOS monomerization and Zn2+ release, and decreased activity. Intact HCAECs exposed to HOCl and HOSCN had decreased eNOS activity and NO2−/NO3− formation (products of NO• decomposition), and increased free Zn2+. Exposure of isolated rat aortic rings to HOSCN resulted in thiol loss, and decreased eNOS activity and cGMP levels. Overall these data indicate that high SCN− levels, as seen in smokers, can increase HOSCN formation and enhance eNOS dysfunction in human endothelial cells, with this potentially contributing to increased atherogenesis in smokers.

Selective Inhibition of the Master Regulator Transcription Factor Egr‐1 With Catalytic Oligonucleotides Reduces Myocardial Injury and Improves Left Ventricular Systolic Function in a Preclinical Model

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 22-08-2013

DOI: 10.1161/JAHA.113.000023

Abstract: Egr‐1 is implicated in the pathogenesis of myocardial ischemia–reperfusion injury. The aim of this study was to ascertain the effectiveness of intracoronary delivery of DNA zyme targeting the transcription factor Egr‐1 at reperfusion following experimental myocardial ischemia. Functional DNA zyme targeting Egr‐1 or a size‐matched scrambled control were delivered via the intracoronary route immediately on reperfusion after 60 minutes' balloon occlusion of the left anterior descending coronary artery in a pig model of myocardial I/R injury (n=7 per treatment group). Heart function and extent of myocardial infarction were determined following intervention by echocardiography and cardiac magnetic resonance imaging, respectively. Hearts were removed and examined for molecular and histological markers of inflammation and apoptosis. Administration of functional DNA zyme led to an overall decrease in the expression of inflammatory markers including intracellular adhesion molecule‐1, tissue factor, and complement 3, with associated decreases in the extent of neutrophil infiltration, oxidative damage, and subsequent apoptosis within the infarct border zone. Functional significance was indicated by an increase in salvaged left ventricular myocardium ( P =0.012), ejection fraction ( P =0.002), and fractional area change ( P =0.039) in the functional DNA zyme–treated group compared with the control. Egr‐1 silencing through intracoronary delivery of a targeting DNA zyme at the time of reperfusion following acute myocardial ischemia decreases myocardial inflammation and apoptosis leading to improved cardiac function.

Synchrotron radiation induced X-ray emission studies of the antioxidant mechanism of the organoselenium drug ebselen

Publisher: Springer Science and Business Media LLC

Date: 11-02-2012

DOI: 10.1007/S00775-012-0879-Y

Abstract: Synchrotron radiation induced X-ray emission (SRIXE) spectroscopy was used to map the cellular uptake of the organoselenium-based antioxidant drug ebselen using differentiated ND15 cells as a neuronal model. The cellular SRIXE spectra, acquired using a hard X-ray microprobe beam (12.8-keV), showed a large enhancement of fluorescence at the K(α) line for Se (11.2-keV) following treatment with ebselen (10 μM) at time periods from 60 to 240 min. Drug uptake was quantified and ebselen was shown to induce time-dependent changes in cellular elemental content that were characteristic of oxidative stress with the efflux of K, Cl, and Ca species. The SRIXE cellular Se distribution map revealed that ebselen was predominantly localized to a discreet region of the cell which, by comparison with the K and P elemental maps, is postulated to correspond to the endoplasmic reticulum. On the basis of these findings, it is hypothesized that a major outcome of ebselen redox catalysis is the induction of cellular stress. A mechanism of action of ebselen is proposed that involves the cell responding to drug-induced stress by increasing the expression of antioxidant genes. This hypothesis is supported by the observation that ebselen also regulated the homeostasis of the transition metals Mn, Cu, Fe, and Zn, with increases in transition metal uptake paralleling known induction times for the expression of antioxidant metalloenzymes.

Coenzyme Q improves LDL resistance to ex vivo oxidation but does not enhance endothelial function in hypercholesterolemic young adults

Publisher: Elsevier BV

Date: 04-2000

DOI: 10.1016/S0891-5849(00)00201-X

Abstract: Oxidative modification of low-density lipoprotein (LDL) may cause arterial endothelial dysfunction in hyperlipidemic subjects. Antioxidants can protect LDL from oxidation and therefore improve endothelial function. Dietary supplementation with coenzyme Q (CoQ(10)) raises its level within LDL, which may subsequently become more resistant to oxidation. Therefore, the aim of this study was to assess whether oral supplementation of CoQ(10) (50 mg three times daily) is effective in reducing ex vivo LDL oxidizability and in improving vascular endothelial function. Twelve nonsmoking healthy adults with hypercholesterolemia (age 34+/-10 years, nine women and three men, total cholesterol 7.4+/-1.1 mmol/l) and endothelial dysfunction (below population mean) at baseline were randomized to receive CoQ(10) or matching placebo in a double-blind crossover study (active lacebo phase 4 weeks, washout 4 weeks). Flow-mediated (FMD, endothelium-dependent) and nitrate-mediated (NMD, smooth muscle-dependent) arterial dilatation were measured by high-resolution ultrasound. CoQ(10) treatment increased plasma CoQ(10) levels from 1.1 +/-0.5 to 5.0+/-2.8 micromol/l (p =.009) but had no significant effect on FMD (4.3+/-2.4 to 5.1+/-3.6 %, p =.99), NMD (21.6+/-6.1 to 20.7+/-7.8 %, p = .38) or serum LDL-cholesterol levels (p = .51). Four subjects were selected randomly for detailed analysis of LDL oxidizability using aqueous peroxyl radicals as the oxidant. In this subgroup, CoQ(10) supplementation significantly increased the time for CoQ(10)H(2) depletion upon oxidant exposure of LDL by 41+/-19 min (p = .04) and decreased the extent of lipid hydroperoxide accumulation after 2 hours by 50+/-37 micromol/l (p =.04). We conclude that dietary supplementation with CoQ(10) decreases ex-vivo LDL oxidizability but has no significant effect on arterial endothelial function in patients with moderate hypercholesterolemia.

Role for Selenium in Metabolic Homeostasis and Human Reproduction

Publisher: MDPI AG

Date: 18-09-2021

DOI: 10.3390/NU13093256

Abstract: Selenium (Se) is a micronutrient essential for life. Dietary intake of Se within the physiological range is critical for human health and reproductive functions. Selenium levels outside the recommended range have been implicated in infertility and variety of other human diseases. However, presently it is not clear how different dietary Se sources are processed in our bodies, and in which form or how much dietary Se is optimum to maintain metabolic homeostasis and boost reproductive health. This uncertainty leads to imprecision in published dietary guidelines and advice for human daily intake of Se and in some cases generating controversies and even adverse outcomes including mortality. The chief aim for this review is to describe the sources of organic and inorganic Se, the metabolic pathways of selenoproteins synthesis, and the critical role of selenprotenis in the thyroid gland homeostasis and reproductive/fertility functions. Controversies on the use of Se in clinical practice and future directions to address these challenges are also described and discussed herein.

Phenolic antioxidants tert-butyl-bisphenol and vitamin E decrease oxidative stress and enhance vascular function in an animal model of rhabdomyolysis yet do not improve acute renal dysfunction

Publisher: Informa UK Limited

Date: 05-07-2011

DOI: 10.3109/10715762.2011.590137

Abstract: Rhabdomyolysis (RM) caused by severe burn releases extracellular myoglobin (Mb) that accumulates in the kidney. Extracellular Mb is a pro-oxidant. This study tested whether supplementation with tert-butyl-bisphenol (BP) or vitamin E (Vit E, as α-tocopherol) at 0.12% w/w in the diet inhibits acute renal failure (ARF) in an animal model of RM. After RM-induction in rats, creatinine clearance decreased (p < 0.01), proteinuria increased (p < 0.001) and renal-tubule damage was detected. Accompanying ARF, biomarkers of oxidative stress (lipid oxidation and hemeoxygenase-1 (HO-1) gene and protein activity) increased in the kidney (p < 0.05). Supplemented BP or Vit E decreased lipid oxidation (p < 0.05) and HO-1 gene/activity and restored aortic cyclic guanylyl monophosphate in control animals (p < 0.001), yet ARF was unaffected. Antioxidant supplementation inhibited oxidative stress, yet was unable to ameliorate ARF in this animal model indicating that oxidative stress in kidney and vascular cells may not be causally related to renal dysfunction elicited by RM.

The synthetic polyphenoltert-butyl-bisphenol inhibits myoglobin-induced dysfunction in cultured kidney epithelial cells

Publisher: Informa UK Limited

Date: 09-06-2010

DOI: 10.3109/10715762.2010.485993

Abstract: Abstract Rhabdomyolysis caused by severe burn releases extracellular myoglobin (Mb) that accumulates in the kidney and urine (maximum [Mb] approximately 50 microM) (termed myoglobinuria). Extracellular Mb can be a pro-oxidant. This study cultured Madin-Darby-canine-kidney-Type-II (MDCK II) cells in the presence of Mb and tested whether supplementation with a synthetic tert-butyl-polyphenol (tert-butyl-bisphenol t-BP) protects these renal cells from dysfunction. In the absence of t-BP, cells exposed to 0-100 microM Mb for 24 h showed a dose-dependent decrease in ATP and the total thiol (TSH) redox status without loss of viability. Gene expression of superoxide dismutases-1/2, haemoxygenase-1 and tumour necrosis factor increased and receptor-mediated endocytosis of transferrin and monolayer permeability decreased significantly. Supplementation with t-BP before Mb-insult maintained ATP and the TSH redox status, diminished antioxidant ro-inflammatory gene responses, enhanced monolayer permissiveness and restored transferrin uptake. Overall, bolstering the total antioxidant capacity of the kidney may protect against oxidative stress induced by experimental myoglobinuria.

NFκB Inhibition Mitigates Serum Amyloid A-Induced Pro-Atherogenic Responses in Endothelial Cells and Leukocyte Adhesion and Adverse Changes to Endothelium Function in Isolated Aorta

Publisher: MDPI AG

Date: 28-12-2018

DOI: 10.3390/IJMS20010105

Abstract: The acute phase protein serum amyloid A (SAA) is associated with endothelial dysfunction and early-stage atherogenesis. Stimulation of vascular cells with SAA increases gene expression of pro-inflammation cytokines and tissue factor (TF). Activation of the transcription factor, nuclear factor kappa-B (NFκB), may be central to SAA-mediated endothelial cell inflammation, dysfunction and pro-thrombotic responses, while targeting NFκB with a pharmacologic inhibitor, BAY11-7082, may mitigate SAA activity. Human carotid artery endothelial cells (HCtAEC) were pre-incubated (1.5 h) with 10 μM BAY11-7082 or vehicle (control) followed by SAA (10 μg/mL 4.5 h). Under these conditions gene expression for TF and Tumor Necrosis Factor (TNF) increased in SAA-treated HCtAEC and pre-treatment with BAY11-7082 significantly (TNF) and marginally (TF) reduced mRNA expression. Intracellular TNF and interleukin 6 (IL-6) protein also increased in HCtAEC supplemented with SAA and this expression was inhibited by BAY11-7082. Supplemented BAY11-7082 also significantly decreased SAA-mediated leukocyte adhesion to apolipoprotein E-deficient mouse aorta in ex vivo vascular flow studies. In vascular function studies, isolated aortic rings pre-treated with BAY11-7082 prior to incubation with SAA showed improved endothelium-dependent vasorelaxation and increased vascular cyclic guanosine monophosphate (cGMP) content. Together these data suggest that inhibition of NFκB activation may protect endothelial function by inhibiting the pro-inflammatory and pro-thrombotic activities of SAA.

Redox-Mediated Rewiring of Signalling Pathways: The Role of a Cellular Clock in Brain Health and Disease

Publisher: MDPI AG

Date: 17-10-2023

DOI: 10.3390/ANTIOX12101873

Selenium Inhibits Renal Oxidation and Inflammation But Not Acute Kidney Injury in an Animal Model of Rhabdomyolysis

Publisher: Mary Ann Liebert Inc

Date: 03-2013

DOI: 10.1089/ARS.2012.4591

Effects of 8 weeks of CPAP on lipid‐based oxidative markers in obstructive sleep apnea: a randomized trial

Publisher: Wiley

Date: 22-12-2014

DOI: 10.1111/JSR.12271

Abstract: Dyslipidaemia and increased oxidative stress have been reported in severe obstructive sleep apnea, and both may be related to the development of cardiovascular disease. We have previously shown in a randomized crossover study in patients with moderate to severe obstructive sleep apnea that therapeutic continuous positive airway pressure treatment for 8 weeks improved postprandial triglycerides and total cholesterol when compared with sham continuous positive airway pressure. From this study we have now compared the effect of 8 weeks of therapeutic continuous positive airway pressure and sham continuous positive airway pressure on oxidative lipid damage and plasma lipophilic antioxidant levels. Unesterified cholesterol, esterified unsaturated fatty acids (cholesteryl linoleate: C18:2 and cholesteryl arachidonate: C20:4 the major unsaturated and oxidizable lipids in low-density lipoproteins), their corresponding oxidized products [cholesteryl ester-derived lipid hydroperoxides and hydroxides (CE-O(O)H)] and antioxidant vitamin E were assessed at 20:30 hours before sleep, and at 06:00 and 08:30 hours after sleep. Amongst the 29 patients completing the study, three had incomplete or missing [CE-O(O)H] data. The mean apnea -hypopnoea index, age and body mass index were 38 per hour, 49 years and 32 kg m(-2) , respectively. No differences in lipid-based oxidative markers or lipophilic antioxidant levels were observed between the continuous positive airway pressure and sham continuous positive airway pressure arms at any of the three time-points [unesterified cholesterol 0.01 mm, P > 0.05 cholesteryl linoleate: C18:2 0.05 mm, P > 0.05 cholesteryl arachidonate: C20:4 0.02 mm, P = 0.05 CE-O(O)H 2.5 nm, P > 0.05 and lipid-soluble antioxidant vitamin E 0.03 μm, P > 0.05]. In this study, accumulating CE-O(O)H, a marker of lipid oxidation, does not appear to play a role in oxidative stress in obstructive sleep apnea.

The nitroxide 4-methoxy TEMPO inhibits neutrophil-stimulated kinase activation in H9c2 cardiomyocytes

Publisher: Elsevier BV

Date: 09-2017

DOI: 10.1016/J.ABB.2017.07.001

Abstract: After acute myocardial infarction (AMI), neutrophils are recruited to the affected myocardium. Hypochlorous acid (HOCl) produced by neutrophil myeloperoxidase (MPO) damages cardiomyocytes and potentially expands the primary infarct. Rat cardiomyocyte-like cells were incubated with isolated human neutrophils treated with chemical activators in the absence or presence of nitroxide 4-methoxy-Tempo (MetT 25 μM) for 4, 6 or 24 h studies with reagent HOCl served as positive control. Treating cardiomyocytes with activated neutrophils or reagent HOCl resulted in a marked increase in protein tyrosine chlorination and a decline in protein tyrosine phosphatase (PTP) activity. On balance our data also supported an increase in phosphorylation of MAPK p38 and ERK1/2 suggestive of an intracellular hyperphosphorylation status and this was accompanied by decreases in cell viability, as judged by assessing caspases-3/7 activity. For cells exposed to activated neutrophils receptor-mediated uptake of transferrin decreased although total matrix metalloproteinase (MMP) activity was unaffected. Addition of MetT ameliorated protein tyrosine chlorination, decreased MAPK activity and restored receptor-mediated transferrin uptake and PTP activity in cardiomyocytes. Overall, adverse effects of neutrophil-derived HOCl on cultured cardiomyocytes were ameliorated by MetT suggesting that nitroxides may be beneficial to inflammatory pathologies, where neutrophil recruitment/activation is a prominent and early feature.

Measuring redox-active species in cells and tissues. Focus on “A case of mistaken identity: are reactive oxygen species actually reactive sulfide species?”

Publisher: American Physiological Society

Date: 04-2016

DOI: 10.1152/AJPREGU.00049.2016

Reaction of Human Myoglobin and H2O2

Publisher: Elsevier BV

Date: 07-2000

DOI: 10.1074/JBC.M000373200

Retraction Notice: The Significance of Neuroglobin in the Brain

Publisher: Bentham Science Publishers Ltd.

Date: 2010

DOI: 10.2174/092986710790112611

Abstract: Since its discovery in 2000, neuroglobin (Nb) has been demonstrated to have an essential and conserved function in vertebrates with the consequential discovery of a neuroprotective role. Nb is a member of the globin superfamily and is predominantly expressed in neurons of the central and peripheral nervous system. Thorough studies have been performed to elucidate the molecular structure of Nb and its ligand binding characteristics. The precise physiological function and mechanism of action of Nb is beginning to be established, with a number of hypotheses having been put forward. While Nb shares an intrinsic affinity for low-molecular weight diatomic gases similar to other globins, the relatively low level of Nb expression in cerebral neurons places limitations on its potential to function as a reservoir for oxygen, especially during periods of acute ischemia. In vitro studies have suggested that the neuroprotective role of Nb may be due to its ability to scavenge reactive oxygen (ROS) and nitrogen (RNS) species. However other studies have proposed Nb as being part of a signalling chain that transmits the redox state of the cell that is protective against oxidative stress or that inhibits apoptosis. This review is intended to summarize the structural, genomic and functional data on neuroglobin to date, thereby providing perspectives for future research on these molecules that may have substantial biomedical implications.

Activated actin-depolymerizing factor/cofilin sequesters phosphorylated microtubule-associated protein during the assembly of Alzheimer-like neuritic cytoskeletal striations

Publisher: Society for Neuroscience

Date: 14-10-2009

DOI: 10.1523/JNEUROSCI.3531-09.2009

Abstract: In Alzheimer's disease (AD), rod-like cofilin aggregates (cofilin–actin rods) and thread-like inclusions containing phosphorylated microtubule-associated protein (pMAP) tau form in the brain (neuropil threads), and the extent of their presence correlates with cognitive decline and disease progression. The assembly mechanism of these respective pathological lesions and the relationship between them is poorly understood, yet vital to understanding the causes of sporadic AD. We demonstrate that, during mitochondrial inhibition, activated actin-depolymerizing factor (ADF)/cofilin assemble into rods along processes of cultured primary neurons that recruit pMAP/tau and mimic neuropil threads. Fluorescence resonance energy transfer analysis revealed colocalization of cofilin-GFP (green fluorescent protein) and pMAP in rods, suggesting their close proximity within a cytoskeletal inclusion complex. The relationship between pMAP and cofilin–actin rods was further investigated using actin-modifying drugs and small interfering RNA knockdown of ADF/cofilin in primary neurons. The results suggest that activation of ADF/cofilin and generation of cofilin–actin rods is required for the subsequent recruitment of pMAP into the inclusions. Additionally, we were able to induce the formation of pMAP-positive ADF/cofilin rods by exposing cells to exogenous amyloid-β (Aβ) peptides. These results reveal a common pathway for pMAP and cofilin accumulation in neuronal processes. The requirement of activated ADF/cofilin for the sequestration of pMAP suggests that neuropil thread structures in the AD brain may be initiated by elevated cofilin activation and F-actin bundling that can be caused by oxidative stress, mitochondrial dysfunction, or Aβ peptides, all suspected initiators of synaptic loss and neurodegeneration in AD.

Effect of vitamin E on aortic lipid oxidation and intimal proliferation after arterial injury in cholesterol-fed rabbits

Publisher: Elsevier BV

Date: 11-2001

DOI: 10.1016/S0891-5849(01)00721-3

Abstract: Oxidized low-density lipoproteins (LDL) are implicated in atherosclerosis. However, large-scale intervention studies designed to test whether antioxidants, such as vitamin E, can ameliorate cardiovascular disease have generated ambivalent results. This may relate to the fact that the mechanism whereby lipid oxidation is initiated in vivo is unknown and the lack of direct evidence for a deficiency of antioxidants in atherosclerotic lesions. Further, there is little evidence to suggest that vitamin E acts as an antioxidant for lipid peroxidation in vivo. Here we tested the antioxidant effect of dietary vitamin E (alpha-tocopherol) supplementation on intimal proliferation and lipid oxidation in balloon-injured, hypercholesterolemic rabbits. alpha-Tocopherol supplementation increased vascular content of alpha-tocopherol over 30-fold compared to nonsupplemented and alpha-tocopherol-deficient chows. Balloon injury resulted in oxidized lipid deposition in the aorta. Maximum levels of primary lipid oxidation products, measured as hydroperoxides of esterified lipid (LOOH) and oxidized linoleate (HODE), were 0.22 and 1.10 nmol/mg, representing 0.21 and 0.39% of the precursor molecule, respectively. Secondary lipid oxidation products, measured as oxysterols, were maximal at 5.60 nmol/mg or 1.48% of the precursor compound. Vascular HODE and oxysterols were significantly reduced by vitamin E supplementation. However, the intima/media ratio of aortic vessels increased with vitamin E supplementation, suggesting that the antioxidant promoted intimal proliferation. Thus, the study demonstrates a dissociation of aortic lipid oxidation and lesion development, and suggests that vitamin E does not prevent lesion development in this animal model.

Neutrophils recruited to the myocardium after acute experimental myocardial infarct generate hypochlorous acid that oxidizes cardiac myoglobin

Publisher: Elsevier BV

Date: 12-2016

DOI: 10.1016/J.ABB.2016.10.013

Abstract: Myocardial inflammation following acute myocardial infarct (AMI) is associated with risk of congestive heart failure. Pro-inflammatory neutrophils were recruited to the damaged myocardium 24 h after permanent coronary ligation in rats to induce AMI as judged by the presence of immune-positive myeloperoxidase (MPO) in the tissues MPO generates the oxidant hypochlorous acid (HOCl). Neutrophils were absent in hearts from Control (untreated) and surgical Sham. Similarly, rats exposed to 1 h coronary ligation (Ischemia) showed no neutrophil infiltrate. Concomitantly, MPO activity increased in left ventricular (LV) homogenates prepared from the AMI group and this was inhibited by paracetamol and the nitroxide TEMPO. The same LV-homogenates showed increased 3-chlorotyrosine/tyrosine ratios (biomarker for MPO-activity). Combined 2D gel/Western blot indicated cardiac myoglobin (Mb) was modified after AMI. Subsequent MALDI-TOF and LC-MS/MS analysis of isolated protein spots revealed increased Mb oxidation in hearts from the AMI group relative to Control, Sham and Ischemia groups. Peptide mass mapping revealed oxidation of Met9 and Met132 to the corresponding sulfoxides yet Cys67 remained unmodified. Therefore, neutrophil-generated HOCl can oxidize cardiac Mb after AMI and this may impact on its function within the affected myocardium: oxidized Mb maybe a useful marker of myocardial inflammation.

Silicon nitride as a versatile growth substrate for microspectroscopic imaging and mapping of individual cells

Publisher: Royal Society of Chemistry (RSC)

Date: 2010

DOI: 10.1039/C001499K

Abstract: Herein is described a general s ling protocol that includes culture, differentiation and fixing of cells in their preferred morphology on the one s le substrate (Si(3)N(4)) to enable subsequent erse modern microspectroscopic analyses. The protocol enables unprecedented correlated and complementary information on the intracellular biochemistry of metabolic processes, diseases and their treatment, which offers the opportunity to revolutionize our understanding of cell and tissue biology at a molecular level. The culture of adherent cells onto inexpensive Si(3)N(4) membranes allows microspectroscopic analyses across the electromagnetic spectrum, from hard X-ray fluorescence (both XRF and XANES), through to visible and fluorescence light microscopies, and infrared microspectroscopy without substrate interference. Adherent mammalian cell lines (3T3-L1 adipocytes and H9c2 cardiac myocytes) illustrate the in vitro application of these protocols. The cells adhered strongly to Si(3)N(4) membranes and visually displayed normal proliferative and phenotypic growth more importantly, rapid alcohol fixation of cells did not affect their structural integrity for subsequent analyses.

α-Tocopheryl succinate induces apoptosis by targeting ubiquinone-binding sites in mitochondrial respiratory complex II

Publisher: Springer Science and Business Media LLC

Date: 31-03-2008

DOI: 10.1038/ONC.2008.69

Rat models of myocardial infarction

Publisher: Georg Thieme Verlag KG

Date: 2006

DOI: 10.1160/TH05-07-0514

Abstract: Animal models of cardiovascular pathology contribute towards understanding and treatment of a broad range of conditions. Specifically in the context of acute myocardial infarction (AMI), rat models have been commonly used in studies of pathogenesis, investigation and novel therapies, although there has often been difficulty in translating experimental findings to clinical benefit. However, recent years have seen two important changes to our clinical approaches to AMI. First, there is increasing recognition that the pathophysiology of human AMI is a process occurring at many levels, not just within the epicardial coronary artery, but also within the microvasculature and the myocardium. Second, contemporary treatments are shifting away from thrombolytic dissolution of epicardial coronary thrombus to direct mechanical approaches using angioplasty and stents. These changes in our understanding of AMI have implications for the relevance of these animal models. The following discussion therefore reviews and examines the current rat models of AMI, places them in a clinical context, discusses their advantages and limitations, and outlines likely future developments, providing an overview of the place of these important models of AMI.

XAS studies of Se speciation in selenite-fed rats

Publisher: Oxford University Press (OUP)

Date: 2014

DOI: 10.1039/C4MT00227J

Abstract: An investigation of selenium speciation in the tissues of selenite-fed rats by principal component analysis of X-ray absorption spectra.

α-Tocopheryl Succinate Inhibits Malignant Mesothelioma byDisrupting the Fibroblast Growth Factor Autocrine Loop

Publisher: Elsevier BV

Date: 07-2005

DOI: 10.1074/JBC.M414498200

Myoglobin Induces Oxidative Stress and Decreases Endocytosis and Monolayer Permissiveness in Cultured Kidney Epithelial Cells without Affecting Viability

Publisher: S. Karger AG

Date: 2008

DOI: 10.1159/000112921

Abstract: i Background: /i Muscle degradation caused by severe burn releases myoglobin (Mb), which accumulates in the kidney (termed myoglobinuria). Mb is a pro-oxidant. i Aim: /i To demonstrate that Mb promotes oxidative stress and dysfunction in cultured Madin-Darby canine kidney type II (MDCK II) cells. i Methods: /i The glutathione redox ratio was used to monitor oxidative stress. Regulation of antioxidant response genes was determined with RT-PCR. Propidium iodide and annexin V staining were markers of necrosis and apoptosis, respectively. Mitochondrial function was assessed by monitoring mitochondrial depolarisation. Endocytosis was determined with immune fluorescence microscopy, and monolayer permeability was monitored with labelled inulin. i Results: /i Kidney epithelial cells exposed to (0–100 µ i M /i ) Mb showed a dose-dependent decrease in the glutathione redox ratio indicative of enhanced oxidative stress. In parallel, the expression of antioxidant genes for superoxide dismutase (SOD)-1/2, inducible haemoxygenase (HO-1) and catalase (CAT) increased in MDCK II cells, coupled with increases in corresponding activity. Notably, apoptosis and necrosis remained unaffected. However, transferrin endocytosis and monolayer permeability decreased significantly, while clathrin distribution and mitochondrial function were unaffected. i Conclusion: /i Low concentrations of Mb promote oxidative stress in kidney epithelial cells that manifest as subtle changes to function without decreasing viability. Whether this impairs kidney function in burns patients is not clear.

Serum amyloid A induction of cytokines in monocytes/macrophages and lymphocytes

Publisher: Elsevier BV

Date: 12-2009

DOI: 10.1016/J.ATHEROSCLEROSIS.2009.05.007

Abstract: Serum amyloid A (SAA) is a biomarker of inflammation. Elevated blood levels in cardiovascular disease and local deposition in atheroma implies a role of SAA as a mediator rather than just a marker of inflammation. This study explored SAA-induced cytokine production and secretion by mononuclear cells. RT-PCR showed that SAA time-dependently induced cytokine mRNAs in peripheral blood mononuclear cells (PBMC) and THP-1 monocytoid cells, and dramatically increased IL-1beta, MCP-1, IL-6, IL-8, IL-10, GM-CSF, TNF, and MIP-1alpha secretion by PBMC to levels 28 to 25,000 fold above baseline, as measured with Bio-Plex kits monocytes were the principle source. SAA induction of cytokines in monocyte-derived macrophages (MDM) was significantly higher than from monocytes from the same donors. SAA time-dependently induced transient and significant upregulation of NF-kappaB1 mRNA inhibitor studies indicate that activation of NF-kappaB through the ERK1/2, p38 and JNK MAPKs and the PI3K pathway was involved. PBMC from 10 patients with coronary artery disease (CAD) spontaneously secreted higher levels of IL-6 and MIP-1alpha after 24h incubation than PBMC from normal controls, whereas SAA-induced levels of all cytokines were similar to controls. Aortic and coronary sinus s ling in 23 CAD patients indicated significant SAA release into the coronary circulation, not evident in 11 controls. SAA can increase monocyte and macrophage cytokine production, possibly at sites of atherosclerosis, thereby contributing to the pro-inflammatory state in coronary artery disease.

[33] Assessment of prooxidant activity of vitamin E in human low-density lipoprotein and plasma

Publisher: Elsevier

Date: 1999

DOI: 10.1016/S0076-6879(99)99036-5

High-Density Lipoprotein (HDL) Inhibits Serum Amyloid A (SAA)-Induced Vascular and Renal Dysfunctions in Apolipoprotein E-Deficient Mice

Publisher: MDPI AG

Date: 15-02-2020

DOI: 10.3390/IJMS21041316

Abstract: Serum amyloid A (SAA) promotes endothelial inflammation and dysfunction that is associated with cardiovascular disease and renal pathologies. SAA is an apoprotein for high-density lipoprotein (HDL) and its sequestration to HDL diminishes SAA bioactivity. Herein we investigated the effect of co-supplementing HDL on SAA-mediated changes to vascular and renal function in apolipoprotein E-deficient (ApoE−/−) mice in the absence of a high-fat diet. Male ApoE−/− mice received recombinant human SAA or vehicle (control) by intraperitoneal (i.p.) injection every three days for two weeks with or without freshly isolated human HDL supplemented by intravenous (i.v.) injection in the two weeks preceding SAA stimulation. Aorta and kidney were harvested 4 or 18 weeks after commencement of treatment. At 4 weeks after commencement of treatment, SAA increased aortic vascular cell adhesion molecule (VCAM)-1 expression and F2-isoprostane level and decreased cyclic guanosine monophosphate (cGMP), consistent with SAA stimulating endothelial dysfunction and promoting atherosclerosis. SAA also stimulated renal injury and inflammation that manifested as increased urinary protein, kidney injury molecule (KIM)-1, and renal tissue cytokine/chemokine levels as well as increased protein tyrosine chlorination and P38 MAPkinase activation and decreased in Bowman’s space, confirming that SAA elicited a pro-inflammatory phenotype in the kidney. At 18 weeks, vascular lesions increased significantly in the cohort of ApoE−/− mice treated with SAA alone. By contrast, pretreatment of mice with HDL decreased SAA pro-inflammatory activity, inhibited SAA enhancement of aortic lesion size and renal function, and prevented changes to glomerular Bowman’s space. Taken together, these data indicate that supplemented HDL reduces SAA-mediated endothelial and renal dysfunction in an atherosclerosis-prone mouse model.

Aberrant Activation of Arachidonic Acid and Eicosanoid Pathways-Targets for Treating Prostate Cancer

Publisher: Bentham Science Publishers Ltd.

Date: 2008

DOI: 10.2174/187221408783421291

Anti-atherogenic effect of coenzyme Q10 in apolipoprotein E gene knockout mice11Dedicated to Lars Ernster for his pioneering contributions to research into coenzyme Q and his genuine passion and enthu

Publisher: Elsevier BV

Date: 08-2000

DOI: 10.1016/S0891-5849(00)00311-7

Abstract: Oxidation of low-density lipoprotein (LDL) lipid is implicated in atherogenesis and certain antioxidants inhibit atherosclerosis. Ubiquinol-10 (CoQ10H2) inhibits LDL lipid peroxidation in vitro although it is not known whether such activity occurs in vivo, and, if so, whether this is anti-atherogenic. We therefore tested the effect of ubiquinone-10 (CoQ10) supplemented at 1% (w/w) on aortic lipoprotein lipid peroxidation and atherosclerosis in apolipoprotein E-deficient (apoE-/-) mice fed a high-fat diet. Hydroperoxides of cholesteryl esters and triacylglycerols (together referred to as LOOH) and their corresponding alcohols were used as the marker for lipoprotein lipid oxidation. Atherosclerosis was assessed by morphometry at the aortic root, proximal and distal arch, and the descending thoracic and abdominal aorta. Compared to controls, CoQ10-treatment increased plasma coenzyme Q, ascorbate, and the CoQ10H2:CoQ10 + CoQ10H2 ratio, decreased plasma alpha-tocopherol (alpha-TOH), and had no effect on cholesterol and cholesterylester alcohols (CE-OH). Plasma from CoQ10-supplemented mice was more resistant to ex vivo lipid peroxidation. CoQ10 treatment increased aortic coenzyme Q and alpha-TOH and decreased the absolute concentration of LOOH, whereas tissue cholesterol, cholesteryl esters, CE-OH, and LOOH expressed per bisallylic hydrogen-containing lipids were not significantly different. CoQ10-treatment significantly decreased lesion size in the aortic root and the ascending and the descending aorta. Together these data show that CoQ10 decreases the absolute concentration of aortic LOOH and atherosclerosis in apoE-/- mice.

Pro-Inflammatory Serum Amyloid a Stimulates Renal Dysfunction and Enhances Atherosclerosis in Apo E-Deficient Mice

Publisher: MDPI AG

Date: 22-11-2021

DOI: 10.3390/IJMS222212582

Abstract: Acute serum amyloid A (SAA) is an apolipoprotein that mediates pro-inflammatory and pro-atherogenic pathways. SAA-mediated signalling is erse and includes canonical and acute immunoregulatory pathways in a range of cell types and organs. This study aimed to further elucidate the roles for SAA in the pathogenesis of vascular and renal dysfunction. Two groups of male ApoE-deficient mice were administered SAA (100 µL, 120 µg/mL) or vehicle control (100 µL PBS) and monitored for 4 or 16 weeks after SAA treatment tissue was harvested for biochemical and histological analyses at each time point. Under these conditions, SAA administration induced crosstalk between NF-κB and Nrf2 transcriptional factors, leading to downstream induction of pro-inflammatory mediators and antioxidant response elements 4 weeks after SAA administration, respectively. SAA treatment stimulated an upregulation of renal IFN-γ with a concomitant increase in renal levels of p38 MAPK and matrix metalloproteinase (MMP) activities, which is linked to tissue fibrosis. In the kidney of SAA-treated mice, the immunolocalisation of inducible nitric oxide synthase (iNOS) was markedly increased, and this was localised to the parietal epithelial cells lining Bowman’s space within glomeruli, which led to progressive renal fibrosis. Assessment of aortic root lesion at the study endpoint revealed accelerated atherosclerosis formation animals treated with SAA also showed evidence of a thinned fibrous cap as judged by diffuse collagen staining. Together, this suggests that SAA elicits early renal dysfunction through promoting the IFN-γ-iNOS-p38 MAPK axis that manifests as the fibrosis of renal tissue and enhanced cardiovascular disease.

Pre-treatment with the synthetic antioxidant T-butyl bisphenol protects cerebral tissues from experimental ischemia reperfusion injury

Publisher: Wiley

Date: 06-06-2014

DOI: 10.1111/JNC.12747

Abstract: Treatments to inhibit or repair neuronal cell damage sustained during focal ischemia/reperfusion injury in stroke are largely unavailable. We demonstrate that dietary supplementation with the antioxidant di-tert-butyl-bisphenol (BP) before injury decreases infarction and vascular complications in experimental stroke in an animal model. We confirm that BP, a synthetic polyphenol with superior radical-scavenging activity than vitamin E, crosses the blood-brain barrier and accumulates in rat brain. Supplementation with BP did not affect blood pressure or endogenous vitamin E levels in plasma or cerebral tissue. Pre-treatment with BP significantly lowered lipid, protein and thiol oxidation and decreased infarct size in animals subjected to middle cerebral artery occlusion (2 h) and reperfusion (24 h) injury. This neuroprotective action was accompanied by down-regulation of hypoxia inducible factor-1α and glucose transporter-1 mRNA levels, maintenance of neuronal tissue ATP concentration and inhibition of pro-apoptotic factors that together enhanced cerebral tissue viability after injury. That pre-treatment with BP ameliorates oxidative damage and preserves cerebral tissue during focal ischemic insult indicates that oxidative stress plays at least some causal role in promoting tissue damage in experimental stroke. The data strongly suggest that inhibition of oxidative stress through BP scavenging free radicals in vivo contributes significantly to neuroprotection. We demonstrate that pre-treatment with ditert-butyl bisphenol(Di-t-Bu-BP) inhibits lipid, protein, and total thiol oxidation and decreases caspase activation and infarct size in rats subjected to middle cerebral artery occlusion (2 h) and reperfusion (24 h) injury. These data suggest that inhibition of oxidative stress contributes significantly to neuroprotection.

Nitroxides Mitigate Neutrophil-Mediated Damage to the Myocardium after Experimental Myocardial Infarction in Rats

Publisher: MDPI AG

Date: 16-10-2020

DOI: 10.3390/IJMS21207650

Abstract: Reperfusion therapy increases survival post-acute myocardial infarction (AMI) while also stimulating secondary oxidant production and immune cell infiltration. Neutrophils accumulate within infarcted myocardium within 24 h post-AMI and release myeloperoxidase (MPO) that catalyses hypochlorous acid (HOCl) production while increasing oxidative stress and inflammation, thereby enhancing ventricular remodelling. Nitroxides inhibit MPO-mediated HOCl production, potentially ameliorating neutrophil-mediated damage. Aim: Assess the cardioprotective ability of nitroxide 4-methoxyTEMPO (4MetT) within the setting of AMI. Methods: Male Wistar rats were separated into 3 groups: SHAM, AMI/R, and AMI/R + 4MetT (15 mg/kg at surgery via oral gavage) and subjected to left descending coronary artery ligation for 30 min to generate an AMI, followed by reperfusion. One cohort of rats were sacrificed at 24 h post-reperfusion and another 28 days post-surgery (with 4MetT (15 mg/kg) administration twice daily). Results: 3-chlorotyrosine, a HOCl-specific damage marker, decreased within the heart of animals in the AMI/R + 4-MetT group 24 h post-AMI, indicating the drug inhibited MPO activity however, there was no evident difference in either infarct size or myocardial scar size between the groups. Concurrently, MPO, NfκB, TNFα, and the oxidation marker malondialdehyde increased within the hearts, with 4-MetT only demonstrating a trend in decreasing MPO and TNF levels. Notably, 4MetT provided a significant improvement in cardiac function 28 days post-AMI, as assessed by echocardiography, indicating potential for 4-MetT as a treatment option, although the precise mechanism of action of the compound remains unclear.

Tumor Antigen Expression in Melanoma Varies According to Antigen and Stage

Publisher: American Association for Cancer Research (AACR)

Date: 02-2006

DOI: 10.1158/1078-0432.CCR-05-1544

Abstract: Purpose: Melanoma cells express antigens that can induce T-cell and antibody responses. Obtaining a detailed understanding of antigen expression in primary and metastatic melanoma is essential if these molecules are to be useful targets for immunotherapy of melanoma. Experimental Design: Malignant melanomas (n = 586) from 426 patients were typed for antigen expression. Multiple s les were available from 86 in iduals, enabling analysis of antigen expression patterns over time. Paraffin-embedded s les were tested by immunohistochemistry for the presence of the differentiation antigens: gp100, Melan-A, tyrosinase, and the “cancer/testis” antigens MAGE-A1, MAGE-A4, and NY-ESO-1. Results: S les were primary tumors (n = 251), lymph node metastases (n = 174), s.c. metastases (n = 71), and distant metastases (n = 90). The differentiation antigens were strongly expressed in 93% to 95% of tumors regardless of stage. In contrast, the frequency of cancer/testis antigen expression in primary tumors for MAGE-A1, MAGE-A4, and NY-ESO-1 was lower (20%, 9%, and 45%, respectively). MAGE-A1 and MAGE-A4 were acquired with advancing disease (to 51% and 44% in distant metastases, respectively) but not NY-ESO-1, which remained positive in 45%. MAGE-A1 expression was twice as prevalent in ulcerated primaries as in nonulcerated primaries (30% versus 15% P = 0.006) and in thicker as opposed to thin melanomas (26% versus 10% P = 0.1). Conclusions: This large series describes patterns of antigen expression in melanoma and their evolution over time. This will help inform decisions about selection of patients and target antigens for melanoma immunotherapy clinical trials.

Expression of human myoglobin in H9c2 cells enhances toxicity to added hydrogen peroxide

Publisher: Elsevier BV

Date: 09-2006

DOI: 10.1016/J.BBRC.2006.07.077

Abstract: Hydrogen peroxide (H2O2) is implicated in cardiac myocyte (CM) damage during myocardial ischemia-reperfusion (IR) injury. Myoglobin (Mb) is present in CM at significant concentrations and reacts with H2O2 to yield one- and two-electron oxidants that may promote myocardial injury. Paradoxically, hearts from mice lacking Mb are more susceptible to H2O2-induced dysfunction than the corresponding controls [U. Flogel, A. Godecke, L.O. Klotz, J. Schrader, Role of myoglobin in the anti-oxidant defense of the heart, FASEB J. 18 (2004) 1156-1158]. We have overexpressed wild-type or Y103F variant of human Mb in cultured CMs to test whether Mb protects against H2O2 insult. Contrary to expectation, cells expressing WT or the Y103F Mb show increased mitochondrial dysfunction and apoptosis, and decreased ATP in response to H2O2 that follows the order native < Y103F Mb < WT human Mb consistent with the increasing pro-oxidant activity for these proteins. These data indicate that (i) Mb promotes oxidative damage to cultured CM and (ii) Mb may be a useful target for the design of inhibitors of myocardial IR injury.

Cosupplementation with a synthetic, lipid-soluble polyphenol and vitamin C inhibits oxidative damage and improves vascular function yet does not inhibit acute renal injury in an animal model of rhabdomyolysis

Publisher: Elsevier BV

Date: 05-2012

DOI: 10.1016/J.FREERADBIOMED.2012.02.011

Abstract: We investigated whether cosupplementation with synthetic tetra-tert-butyl bisphenol (BP) and vitamin C (Vit C) ameliorated oxidative stress and acute kidney injury (AKI) in an animal model of acute rhabdomyolysis (RM). Rats were ided into groups: Sham and Control (normal chow), and BP (receiving 0.12% w/w BP in the diet 4 weeks) with or without Vit C (100mg/kg ascorbate in PBS ip at 72, 48, and 24h before RM induction). All animals (except the Sham) were treated with 50% v/v glycerol/PBS (6 mL/kg injected into the hind leg) to induce RM. After 24h, urine, plasma, kidneys, and aortae were harvested. Lipid oxidation (assessed as cholesteryl ester hydroperoxides and hydroxides and F(2)-isoprostanes accumulation) increased in the kidney and plasma and this was coupled with decreased aortic levels of cyclic guanylylmonophosphate (cGMP). In renal tissues, RM stimulated glutathione peroxidase (GPx)-4, superoxide dismutase (SOD)-1/2 and nuclear factor kappa-beta (NFκβ) gene expression and promoted AKI as judged by formation of tubular casts, damaged epithelia, and increased urinary levels of total protein, kidney-injury molecule-1 (KIM-1), and clusterin. Supplementation with BP±Vit C inhibited the two indices of lipid oxidation, down-regulated GPx-4, SOD1/2, and NF-κβ gene responses and restored aortic cGMP, yet renal dysfunction and altered kidney morphology persisted. By contrast, supplementation with Vit C alone inhibited oxidative stress and diminished cast formation and proteinuria, while other plasma and urinary markers of AKI remained elevated. These data indicate that lipid- and water-soluble antioxidants may differ in terms of their therapeutic impact on RM-induced renal dysfunction.

Moxonidine Increases Uptake of Oxidised Low-Density Lipoprotein in Cultured Vascular Smooth Muscle Cells and Inhibits Atherosclerosis in Apolipoprotein E-Deficient Mice

Publisher: MDPI AG

Date: 14-02-2023

DOI: 10.3390/IJMS24043857

Abstract: This study aimed to investigate the effect of the sympatholytic drug moxonidine on atherosclerosis. The effects of moxonidine on oxidised low-density lipoprotein (LDL) uptake, inflammatory gene expression and cellular migration were investigated in vitro in cultured vascular smooth muscle cells (VSMCs). The effect of moxonidine on atherosclerosis was measured by examining aortic arch Sudan IV staining and quantifying the intima-to-media ratio of the left common carotid artery in apolipoprotein E-deficient (ApoE−/−) mice infused with angiotensin II. The levels of circulating lipid hydroperoxides in mouse plasma were measured by ferrous oxidation-xylenol orange assay. Moxonidine administration increased oxidised LDL uptake by VSMCs via activation of α2 adrenoceptors. Moxonidine increased the expression of LDL receptors and the lipid efflux transporter ABCG1. Moxonidine inhibited mRNA expression of inflammatory genes and increased VSMC migration. Moxonidine administration to ApoE−/− mice (18 mg/kg/day) decreased atherosclerosis formation in the aortic arch and left common carotid artery, associated with increased plasma lipid hydroperoxide levels. In conclusion, moxonidine inhibited atherosclerosis in ApoE−/− mice, which was accompanied by an increase in oxidised LDL uptake by VSMCs, VSMC migration, ABCG1 expression in VSMCs and lipid hydroperoxide levels in the plasma.

Catalase-Like Antioxidant Activity is Unaltered in Hypochlorous Acid Oxidized Horse Heart Myoglobin

Publisher: MDPI AG

Date: 18-09-2019

DOI: 10.3390/ANTIOX8090414

Abstract: Activated neutrophils release myeloperoxidase that produces the potent oxidant hypochlorous acid (HOCl). Exposure of the oxygen transport protein horse heart myoglobin (hhMb) to HOCl inhibits Iron III (Fe(III))-heme reduction by cytochrome b5 to oxygen-binding Iron II (Fe(II))Mb. Pathological concentrations of HOCl yielded myoglobin oxidation products of increased electrophoretic mobility and markedly different UV/Vis absorbance. Mass analysis indicated HOCl caused successive mass increases of 16 a.m.u., consistent serial addition of molecular oxygen to the protein. By contrast, parallel analysis of protein chlorination by quantitative mass spectrometry revealed a comparatively minor increase in the 3-chlorotyrosine/tyrosine ratio. Pre-treatment of hhMb with HOCl affected the peroxidase reaction between the hemoprotein and H2O2 as judged by a HOCl dose-dependent decrease in spin-trapped tyrosyl radical detected by electron paramagnetic resonance (EPR) spectroscopy and the rate constant of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) oxidation. By contrast, Mb catalase-like antioxidant activity remained unchanged under the same conditions. Notably, HOCl-modification of Mb decreased the rate of ferric-to-ferrous Mb reduction by a cytochrome b5 reductase system. Taken together, these data indicate oxidizing HOCl promotes Mb oxidation but not chlorination and that oxidized Mb shows altered Mb peroxidase-like activity and diminished rates of one-electron reduction by cytochrome b5 reductase, possibly affecting oxygen storage and transport however, Mb-catalase-like antioxidant activity remains unchanged.

Supplementation with a synthetic polyphenol limits oxidative stress and enhances neuronal cell viability in response to hypoxia-re-oxygenation injury

Publisher: Elsevier BV

Date: 07-2008

DOI: 10.1016/J.BRAINRES.2008.04.044

Abstract: Oxidative stress is associated with the pathology of acute and chronic neurodegenerative disease. Cultured human neuronal cells exposed to experimental hypoxia-re-oxygenation (H/R) injury responded with an increased production of reactive oxygen species (ROS) and a significant decrease in intracellular ATP. Expression of genes encoding for hypoxia-inducible factor 1-alpha (HIF1-alpha), inducible haemoxygenase-1 (HO-1), glucose transporter-1 (Glut-1), the oxygen-sensor neuroglobin (Nb) and Cu,Zn-superoxide dismutase (SOD1), catalase (CAT) and glutathione peroxidase-1 (Gpx-1) increased significantly in response to the insult. Enhanced expression of HO-1, SOD1 and CAT correlated with an increase in the corresponding protein activity. Despite the cellular response to bolster antioxidant capacity, apoptosis and necrosis increased following H/R injury. In contrast, ROS accumulation, the endogenous gene response and cell death was limited in neuronal cells pre-incubated with 50 or 100, but not 10 microM of the phenolic antioxidant 3,3',5,5'-tetra-t-butyl-biphenyl-4,4'-diol (BP) prior to H/R injury. These data indicate that the early endogenous gene response to H/R injury is unable to inhibit neuronal dysfunction and that increasing cellular antioxidant capacity with a synthetic polyphenol (>10 microM) is potentially neuro-protective.

XAS and XFM studies of selenium and copper speciation and distribution in the kidneys of selenite-supplemented rats

Publisher: Oxford University Press (OUP)

Date: 2014

DOI: 10.1039/C4MT00088A

Abstract: Se and Cu were colocalised in the kidneys of selenite-fed rats, but there was no evidence of Se–Cu bonding.

Protective Role for Antioxidants in Acute Kidney Disease

Publisher: MDPI AG

Date: 07-07-2017

DOI: 10.3390/NU9070718

Abstract: Acute kidney injury causes significant morbidity and mortality in the community and clinic. Various pathologies, including renal and cardiovascular disease, traumatic injury/rhabdomyolysis, sepsis, and nephrotoxicity, that cause acute kidney injury (AKI), induce general or regional decreases in renal blood flow. The ensuing renal hypoxia and ischemia promotes the formation of reactive oxygen species (ROS) such as superoxide radical anions, peroxides, and hydroxyl radicals, that can oxidatively damage biomolecules and membranes, and affect organelle function and induce renal tubule cell injury, inflammation, and vascular dysfunction. Acute kidney injury is associated with increased oxidative damage, and various endogenous and synthetic antioxidants that mitigate source and derived oxidants are beneficial in cell-based and animal studies. However, the benefit of synthetic antioxidant supplementation in human acute kidney injury and renal disease remains to be realized. The endogenous low-molecular weight, non-proteinaceous antioxidant, ascorbate (vitamin C), is a promising therapeutic in human renal injury in critical illness and nephrotoxicity. Ascorbate may exert significant protection by reducing reactive oxygen species and renal oxidative damage via its antioxidant activity, and/or by its non-antioxidant functions in maintaining hydroxylase and monooxygenase enzymes, and endothelium and vascular function. Ascorbate supplementation may be particularly important in renal injury patients with low vitamin C status.

Cyclic voltammetric and E.P.R. spectroscopic studies on apical substituent effects in radical anions of 9-substituted and 9,10-disubstituted nitroethanoanthracenes

Publisher: CSIRO Publishing

Date: 1996

DOI: 10.1071/CH9961279

Abstract: Cyclic voltammetry and electron paramagnetic resonance spectroscopy were used to examine apical substituent effects on the properties of Me2SO solutions of the radical anions from 9-substituted and 9,10-disubstituted 2- and 3-nitro-9,10-dihydro-9,10-ethanoanthracenes (1)-(24). The reductions of the nitro group are, in general, reversible at 100 mV s-1 and at 20°, except where there are coupled intra-or inter-molecular electron or proton transfer reactions with aliphatic bridgehead substituents, such as a carboxylic acid or iodine. The substituent effects for the meta- and para-nitroethanoanthracene systems are both similar and additive. This similarity in the meta and para polar substituent effects is attributed to the orthogonality of the π*(ArNO2/ArNO2-) orbital with the σ* orbital of the carbon substituent (C-X) groups at the bridgehead positions. Overall, the meta substituent effect was slightly lower than that for corresponding simple meta-nitrobenzyl systems, but the para-nitro systems showed substituent effects that are a factor of 2 smaller than that for corresponding simple para-nitrobenzyl systems. These linear correlations between the substituent effects and redox potentials have been used to estimate the redox potentials of irreversible systems, which are required for digital simulations of reactions involving nitroaryl radical anions. Only small substituent effects are present in hyperfine coupling with the aliphatic and aromatic protons of the nitroaromatic radical anions of ethanoanthracenes (1)-(13), but a clear trend to lower nitrogen hyperfine values was observed with increasing electron-withdrawing ability of the apical substituent. In addition, no spin density was transferred to the benzylic bridgehead substituent in any of the nitro radical anions studied, clearly demonstrating that the bond between the bridgehead substituent and the carbon at a benzylic position is orthogonal to the π-system of the nitroaromatic ring bearing the odd electron.

Effects of hydrogen peroxide and apolipoprotein E isoforms on apolipoprotein E trafficking in HepG2 cells

Publisher: Wiley

Date: 25-11-2009

DOI: 10.1111/J.1440-1681.2009.05306.X

Abstract: 1. The major source of apolipoprotein E (apoE) is the liver. In the present study, the effects of oxidative stress and apoE isoforms on apoE distribution and trafficking were established using the HepG2 liver tumour cell line. 2. Hydrogen peroxide (0, 25, 250 and 1000 micromol/L) was associated with rapid and concentration-dependent redistribution of apoE into the early endosomal compartment. This redistribution was achieved with a much lower concentration (25 micromol/L) than that needed to induce changes in intracellular apoE mRNA expression, apoE protein levels and markers of oxidative stress (250-1000 micromol/L). 3. Live cell imaging of apoE3-green fluorescent protein revealed a significant decrease in traffic velocity in response to oxidative stress. 4. The E4 isoform was associated with reduced trafficking velocity compared with the E3 isoform under basal conditions. 5. The results indicate that oxidative stress and apoE isoforms influence apoE trafficking and distribution within HepG2 cells. Altered apoE hepatocyte trafficking may provide a mechanistic link between oxidative stress, ageing and some diseases in older people.

Selenium Metabolism in Cancer Cells: The Combined Application of XAS and XFM Techniques to the Problem of Selenium Speciation in Biological Systems

Publisher: MDPI AG

Date: 21-05-2013

DOI: 10.3390/NU5051734

Polymorphonuclear leukocyte phagocytic function increases in plasminogen knockout mice

Publisher: Elsevier BV

Date: 2008

DOI: 10.1016/J.THROMRES.2007.12.013

Abstract: Mice lacking plasminogen (PG-/-) require alternative pathways of fibrinolysis for survival. This may depend on polymorphonuclear leukocytes (PMN) that can clear soluble and insoluble fibrin(ogen) through PG-independent processes. Our objective was to demonstrate that PMNs from PG-/- mice exhibit increased Mac-1 dependent phagocytic activity, which may explain their increased fibrin(ogen)lytic activity compared with wild type (PG+/+) mice. Phagocytic activity of PMNs from PG-/- and PG+/+ mice was compared following exposure to Staphylococcus aureus (S. aureus) particles and the expression of Mac-1 was assessed in parallel by flow cytometric analysis. Resistance to phorbol-12-myristate-13-acetate (PMA)-induced cell death was compared between PMNs from the different genotypes. Stimulation of PG-/- PMNs by opsonized S. aureus diluted in PG-/- plasma significantly increased phagocytosis (15-fold) compared with stimulation of PG+/+ PMNs in PG+/+ plasma. Incubation of PG-/- PMNs with PG+/+ plasma (control) or PG-/- plasma supplemented with human PG inhibited this increased phagocytic activity. Mac-1 cell surface density increased 6.2+/-1.0-fold in PG-/- PMNs versus 2.9+/-0.6-fold in PG+/+ PMNs (P < 0.01) indicating that Mac-1 may be associated with increased phagocytic activity. Supporting this, treatment of PG-/- PMNs with an anti-Mac-1 antibody in PG-/- plasma inhibited phagocytic activity. In addition, physiologic PG blocked Mac-1 accessibility at the surface of PMNs. Addition of PMA resulted in 33% death of PMNs from PG-/- mice versus 68% in PG+/+ controls (P < 0.001). PMNs from PG-/- mice exhibit a Mac-1 dependent increase in phagocytic activity that is suppressed with human PG, an anti-Mac-1 antibody or the plasma from PG+/+ mice. The propensity for PMNs from PG-/- mice to be activated in response to PMA together with their relative resistance to PMA-toxicity may contribute to increased PMN half-life and enhanced fibrin(ogen) clearance in the setting of PG deficiency.

Anti-proliferative and cytotoxic activities of the flavonoid isoliquiritigenin in the human neuroblastoma cell line SH-SY5Y

Publisher: Elsevier BV

Date: 02-2019

DOI: 10.1016/J.CBI.2018.11.022

Abstract: Neuroblastoma is a common childhood cancer with high mortality. We evaluated the capacity of the flavonoid, isoliquiritigenin (4,2',4'-trihydroxychalcone ISL) to inhibit cellular proliferation and migration in the human neuroblastoma cell line SH-SY5Y. Incubation of cultured SH-SY5Y cells with 20-100 μM ISL decreased cell confluency (15-70%) after 24 h incubation, while 10-100 μM ISL (24 h) depleted intracellular ATP stores (15-90% vs vehicle-treated control) after 24 h incubation. ISL-mediated cell toxicity did not involve intracellular caspase 3/7 activation, externalization of phosphatidylserine on the cell membrane or stimulation of TNF and IL-1β release, all indicating that the flavonoid did not induce apoptosis. Pre-treatment of cells with necrostatin-1, a necroptosis inhibitor, significantly restored ATP levels (ATP levels increased 12-42%) in ISL-treated neuroblastoma cells indicative of enhanced viability. By contrast, RIP1 phosphorylation status remained unchanged in cells treated with ISL although the intracellular ratio of phosphorylated/total parental RIP1 increased after ISL treatment on SH-SY5Y cells indicating that ISL decreased levels of native RIP1. In addition, ISL treatment inhibited SH-SY5Y cell migration roliferation in a scratch assay and arrested cell cycle transition by significantly decreasing the number of cells in G0/G1 phase and increasing populations by ~10% in S (primarily) and G2/M (lesser extent) phases. The intracellular ratio of phosphorylated/total ERK 1/2 and p38 remained unchanged after ISL treatment (up to 40 μM) ERK activation was only determined at ISL dose well above the experimental IC

Redox Control of Endothelial Function and Dysfunction: Molecular Mechanisms and Therapeutic Opportunities

Publisher: Mary Ann Liebert Inc

Date: 10-2008

DOI: 10.1089/ARS.2008.2027

Abstract: The endothelium is essential for the maintenance of vascular homeostasis. Central to this role is the production of endothelium-derived nitric oxide (EDNO), synthesized by the endothelial isoform of nitric oxide synthase (eNOS). Endothelial dysfunction, manifested as impaired EDNO bioactivity, is an important early event in the development of various vascular diseases, including hypertension, diabetes, and atherosclerosis. The degree of impairment of EDNO bioactivity is a determinant of future vascular complications. Accordingly, growing interest exists in defining the pathologic mechanisms involved. Considerable evidence supports a causal role for the enhanced production of reactive oxygen species (ROS) by vascular cells. ROS directly inactivate EDNO, act as cell-signaling molecules, and promote protein dysfunction, events that contribute to the initiation and progression of endothelial dysfunction. Increasing data indicate that strategies designed to limit vascular ROS production can restore endothelial function in humans with vascular complications. The purpose of this review is to outline the various ways in which ROS can influence endothelial function and dysfunction, describe the redox mechanisms involved, and discuss approaches for preventing endothelial dysfunction that may highlight future therapeutic opportunities in the treatment of cardiovascular disease.

Substituent-Dependent Electron Transfer in Radical Anions of 9- and 9,10-Disubstituted 2,7-Dinitro-9,10-dihydro-9,10-ethanoanthracenes

Publisher: Wiley

Date: 10-1996

DOI: 10.1002/(SICI)1097-458X(199610)34:10<761::AID-OMR951>3.0.CO;2-1

Optimal Preparation of Formalin Fixed Samples for Peptide Based Matrix Assisted Laser Desorption/Ionization Mass Spectrometry Imaging Workflows

Publisher: MyJove Corporation

Date: 16-01-2018

DOI: 10.3791/56778

Serum Amyloid A Receptor Blockade and Incorporation into High-Density Lipoprotein Modulates Its Pro-Inflammatory and Pro-Thrombotic Activities on Vascular Endothelial Cells

Publisher: MDPI AG

Date: 15-05-2015

DOI: 10.3390/IJMS160511101

Molecules in focus: Cytosolic phospholipase A2-α

Publisher: Elsevier BV

Date: 05-2009

DOI: 10.1016/J.BIOCEL.2008.07.017

Abstract: Cytosolic phospholipase A(2)-alpha (cPLA(2)-alpha) cleaves its preferred substrate, arachidonic acid, at the sn-2 position of membrane glycerophospholipids. Stimulation of cells with agents that mobilize intracellular calcium and/or promote the phosphorylation of cPLA(2)-alpha leads to (i) translocation of the enzyme from cytosol to endoplasmic reticulum, Golgi apparatus and perinuclear membranes-where it associates with the arachidonic acid in close proximity to downstream eicosanoid-producing enzymes and (ii) the change in configuration induced by phosphorylation increases the phospholipid binding affinity and arachidonic acid release. As a mediator of growth factors, cytokines, chemokines, and hormones that modulate survival and growth in various cell types, cPLA(2)-alpha has attracted considerable attention as a potential therapeutic target in control of inflammation and cancer. The importance of the enzyme may have been underestimated by the relatively normal phenotype in the enzyme knockout animals. A clear phenotype has emerged when these knockout animals are used as models of various diseases.

Hypochlorous acid oxidizes methionine and tryptophan residues in myoglobin

Publisher: Elsevier BV

Date: 09-2008

DOI: 10.1016/J.FREERADBIOMED.2008.06.010

Abstract: After acute myocardial infarction (AMI), infiltrating proinflammatory cells generate two-electron oxidants such as hypochlorous acid (HOCl). Myoglobin (Mb) is present at approximately 0.3 mM in cardiomyocytes and, therefore, represents a significant target for oxidation. Exposure of horse Mb (50 microM) to reagent HOCl (0-500 microM) or activated human neutrophils (4-40x10(6) cells/ml) yielded oxidized Mb (Mb(ox)) as judged by amino acid analysis and peptide mass mapping. HOCl/Mb ratios of 1-5 mol/mol gave Mb(ox) with up to four additional oxygen atoms. Hydrolysis of Mb(ox) followed by amino acid analysis indicated that methionine (Met) and tryptophan (Trp) residues were modified by HOCl. Peptide mass mapping revealed that Met55 was oxidized at a lower HOCl/Mb ratio than Met131 and this preceded Trp7/14 modification (susceptibility Met55>Met131>Trp7>Trp14). Incubation of Mb with activated neutrophils and physiological chloride anion yielded Mb(ox) with a composition similar to that determined with HOCl/Mb ratios <2 mol/mol, with oxidation of Met, but not Trp, detected. These data indicate that Mb undergoes site-specific oxidation depending on the HOCl rotein ratio. As Mb is released from necrotic cardiomyocytes into the vasculature after AMI, HOCl-modified Mb may be a useful surrogate marker to gauge the extent of myocardial inflammation.

Serum amyloid A stimulates cultured endothelial cells to migrate and proliferate: inhibition by the multikinase inhibitor BIBF1120

Publisher: Wiley

Date: 23-08-2013

DOI: 10.1111/1440-1681.12148

Abstract: In the present study, we tested whether serum amyloid A (SAA) protein, an established biomarker of inflammation, also plays a role in stimulating neovascularization. To evaluate this possibility, human carotid artery endothelial (HCtAE) cells were cultured and cellular migration and the proinflammatory and/or thrombotic activity of SAA (0, 1 or 10 μg/mL) on vascular endothelial cells was verified by determining gene regulation relative to control (in the absence of SAA). Exposure of HCtAE cells to SAA increased expression of the transcription factor nuclear factor-κB (NFKB), tumour necrosis factor (TNF) and pro-coagulative tissue factor (F3), and stimulated phosphorylation of the P65 subunit of the NFKB complex. Enhanced production of TNF and NFKB was paralleled by increased vascular endothelial growth factor (VEGF) mRNA and protein expression, as demonstrated by quantitative polymerase chain reaction, western blotting and ELISA. Administration of 10 μg/mL SAA enhanced endothelial cell migration (1.6-fold vs control), stimulated regrowth of HCtAE cells after mechanical injury (~1.2-fold vs control) and increased endothelial tube formation relative to control after 6 h. The SAA-mediated enhancement of endothelial cell migration, proliferation and tube formation were markedly inhibited by pretreatment of HCtAE cells with the multi-angiokinase receptor inhibitor BIBF1120 (100 nmol/L), although SAA-stimulated gene responses for F3 and NFKB were unaffected by 100 nmol/L BIBF1120 pretreatment. Overall, BIBF1120 inhibited the pro-angiogenic activity of SAA on vascular endothelial cells in this experimental model of inflammation.

Pleiotropic, heart rate-independent cardioprotection by ivabradine

Publisher: Wiley

Date: 21-07-2015

DOI: 10.1111/BPH.13220

Conjugates of Desferrioxamine B (DFOB) with Derivatives of Adamantane or with Orally Available Chelators as Potential Agents for Treating Iron Overload

Publisher: American Chemical Society (ACS)

Date: 30-12-2009

DOI: 10.1021/JM9016703

Abstract: Desferrioxamine B (DFOB) conjugates with adamantane-1-carboxylic acid, 3-hydroxyadamantane-1-carboxylic acid, 3,5-dimethyladamantane-1-carboxylic acid, adamantane-1-acetic acid, 4-methylphenoxyacetic acid, 3-hydroxy-2-methyl-4-oxo-1-pyridineacetic acid (N-acetic acid derivative of deferiprone), or 4-[3,5-bis(2-hydroxyphenyl)-1,2,4-triazol-1-yl]benzoic acid (deferasirox) were prepared and the integrity of Fe(III) binding of the compounds was established from electrospray ionization mass spectrometry and RP-HPLC measurements. The extent of intracellular (59)Fe mobilized by the DFOB-3,5-dimethyladamantane-1-carboxylic acid adduct was 3-fold greater than DFOB alone, and the IC(50) value of this adduct was 6- or 15-fold greater than DFOB in two different cell types. The relationship between logP and (59)Fe mobilization for the DFOB conjugates showed that maximal mobilization of intracellular (59)Fe occurred at a logP value approximately 2.3. This parameter, rather than the affinity for Fe(III), appears to influence the extent of intracellular (59)Fe mobilization. The low toxicity-high Fe mobilization efficacy of selected adamantane-based DFOB conjugates underscores the potential of these compounds to treat iron overload disease in patients with transfusional-dependent disorders such as beta-thalassemia.

Evidence That Niacin Inhibits Acute Vascular Inflammation and Improves Endothelial Dysfunction Independent of Changes in Plasma Lipids

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 05-2010

DOI: 10.1161/ATVBAHA.109.201129

Abstract: Objective— To determine if niacin can confer cardiovascular benefit by inhibiting vascular inflammation and improving endothelial function independent of changes in plasma lipid and lipoprotein levels. Methods and Results— New Zealand white rabbits received normal chow or chow supplemented with 0.6% or 1.2% (wt/wt) niacin. This regimen had no effect on plasma cholesterol, triglyceride, or high-density lipoprotein levels. Acute vascular inflammation and endothelial dysfunction were induced in the animals with a periarterial carotid collar. At the 24-hour postcollar implantation, the endothelial expression of vascular cell adhesion molecule-1, intercellular adhesion molecule-1, and monocyte chemotactic protein-1 was markedly decreased in the niacin-supplemented animals compared with controls. Niacin also inhibited intima-media neutrophil recruitment and myeloperoxidase accumulation, enhanced endothelial-dependent vasorelaxation and cyclic guanosine monophosphate production, increased vascular reduced glutathione content, and protected against hypochlorous acid–induced endothelial dysfunction and tumor necrosis factor α–induced vascular inflammation. Conclusion— Previous human intervention studies have demonstrated that niacin inhibits coronary artery disease. This benefit is thought to be because of its ability to reduce low-density lipoprotein and plasma triglyceride levels and increase high-density lipoprotein levels. The present study showed that niacin inhibits vascular inflammation and protects against endothelial dysfunction independent of these changes in plasma lipid levels.

Neuroglobin Overexpression in Cultured Human Neuronal Cells Protects Against Hydrogen Peroxide InsultviaActivating Phosphoinositide-3 Kinase and Opening the Mitochondrial K_ATPChannel

Publisher: Mary Ann Liebert Inc

Date: 15-09-2010

DOI: 10.1089/ARS.2009.2977

Abstract: Cultured neurons tolerate low H(2)O(2) concentrations ( or =100 microM), neurons increase expression of the gene encoding for inducible hemoxygenase-1 while superoxide dismutase-2 and catalase remain unchanged. Despite this adaptive response, the endogenous antioxidant systems are overwhelmed, leading to decreased viability. Elevating the neuronal cell content of human neuroglobin (Ngb) prior to insult with 100 or 200 microM H(2)O(2) enhanced cell viability and this resulted in a significant decrease in oxidative stress and an increase in the intracellular ATP concentration, whereas in parental cells exposed to the same H(2)O(2)-insult, oxidative stress and ATP increased and decreased, respectively. The mechanism for this increase in ATP involves sustained activation of the mito-K(ATP) channel and an increase in phosphoinositide-3 kinase (PI3K)-mediated phosphorylation of Akt. Pharmacological inhibitors directed toward PI3K (wortmannin and LY294002), or the mito-K(ATP) channel (glybenclamide) inhibited the H(2)O(2)-mediated increase in ATP in cells overexpressing human Ngb and consequently cell viability decreased. Neuroglobin's ability to bolster the intracellular pool of ATP in response to added H(2)O(2) is central to the preservation of cytoskeletal integrity and cell viability.

Role of tyrosine-103 in myoglobin peroxidase activity: Kinetic and steady-state studies on the reaction of wild-type and variant recombinant human myoglobins with H2O2

Publisher: American Chemical Society (ACS)

Date: 30-08-2002

DOI: 10.1021/BI025835W

Abstract: Myoglobin (Mb) catalyzes a range of oxidation reactions in the presence of hydrogen peroxide (H(2)O(2)) through a peroxidase-like cycle. C110A and Y103F variants of human Mb have been constructed to assess the effects of removing electron-rich oxidizable amino acids from the protein on the peroxidase activity of Mb: a point mutation at W14 failed to yield a viable protein. Point mutations at C110 and Y103 did not result in significant changes to structural elements of the heme pocket, as judged by low-temperature electron paramagnetic spectroscopy (EPR) studies on the ground-state ferric proteins. However, compared to the native protein, the yield of globin radical (globin*) was significantly decreased for the Y103F but not the C110A variant Mb upon reaction of the respective proteins with H(2)O(2). In contrast with our expectation that inhibiting pathways of intramolecular electron transfer may lead to enhanced Mb peroxidase activity, mutation of Y103 marginally decreased the rate constant for reaction of Mb with H(2)O(2) (1.4-fold) as judged by stopped-flow kinetic analyses. Consistent with this decrease in rate constant, steady-state analyses of Y103F Mb-derived thioanisole sulfoxidation indicated decreased V(max) and increased K(m) relative to the wild-type control. Additionally, thioanisole sulfoxidation proceeded with lower stereoselectivity, suggesting that Y103 plays a significant role in substrate binding and orientation in the heme pocket of Mb. Together, these results show that electron transfer within the globin portion of the protein is an important modulator of its stability and catalytic activity. Furthermore, the hydrogen-bonding network involving the residues that line the heme pocket of Mb is crucial to both efficient peroxidase activity and stereospecificity.

Analogues of desferrioxamine B designed to attenuate iron-mediated neurodegeneration: synthesis, characterisation and activity in the MPTP-mouse model of Parkinson's disease

Publisher: Oxford University Press (OUP)

Date: 2017

DOI: 10.1039/C7MT00039A

Abstract: One dual-function ( 2 ) and one first-generation ( 9 ) conjugate of the Fe( iii ) chelator desferrioxamine B (DFOB, 1 ) showed significant rescue of neurons in the MPTP mouse model of Parkinson's disease.

Vitamin E Analogues Inhibit Angiogenesis by Selective Induction of Apoptosis in Proliferating Endothelial Cells: The Role of Oxidative Stress

Publisher: American Association for Cancer Research (AACR)

Date: 15-12-2007

DOI: 10.1158/0008-5472.CAN-07-3034

Abstract: “Mitocans” from the vitamin E group of selective anticancer drugs, α-tocopheryl succinate (α-TOS) and its ether analogue α-TEA, triggered apoptosis in proliferating but not arrested endothelial cells. Angiogenic endothelial cells exposed to the vitamin E analogues, unlike their arrested counterparts, readily accumulated reactive oxygen species (ROS) by interfering with the mitochondrial redox chain and activating the intrinsic apoptotic pathway. The vitamin E analogues inhibited angiogenesis in vitro as assessed using the “wound-healing” and “tube-forming” models. Endothelial cells deficient in mitochondrial DNA (mtDNA) were resistant to the vitamin E analogues, both in ROS accumulation and apoptosis induction, maintaining their angiogenic potential. α-TOS inhibited angiogenesis in a mouse cancer model, as documented by ultrasound imaging. We conclude that vitamin E analogues selectively kill angiogenic endothelial cells, suppressing tumor growth, which has intriguing clinical implications. [Cancer Res 2007 (24):11906–13]

Protective effect of a synthetic anti-oxidant on neuronal cell apoptosis resulting from experimental hypoxia re-oxygenation injury

Publisher: Wiley

Date: 08-03-2006

DOI: 10.1111/J.1471-4159.2006.03726.X

Abstract: Oxidative stress is associated with the pathology of acute and chronic neurodegenerative disease. Cultured neuronal cells exposed to hypoxia-reoxygenation (H/R) injury, as a model for stroke, yield a burst of reactive oxygen species (ROS) as measured with electron paramagnetic resonance (EPR) spectroscopy in combination with spin trapping. Added superoxide dismutase inhibited spin-adduct formation verifying that superoxide radical anion was formed in neuronal cells following H/R injury. The intracellular ADP/ATP ratio increased rapidly over the first 5 h following injury and this was due primarily to the decreased cellular pools of ATP, consistent with the notion that H/R promotes mitochondrial dysfunction leading to decreased ATP reserve and increased ROS formation. As an early response to the enhanced oxidative stress, genes encoding for hypoxia-inducible factor 1-alpha (HIF1-alpha), inducible haemoxygenase-1 (HO-1), and the oxygen-sensor neuroglobin increased significantly. Up-regulation of the HO-1 gene was paralleled by increased HO protein expression and activity. Despite this cellular response, apoptosis increased significantly following H/R injury indicating that the endogenous anti-oxidant defenses were unable to protect the cells. In contrast, addition of a phenolic anti-oxidant, bisphenol (BP), prior to H/R injury, inhibited ROS production and gene regulation and significantly decreased neuronal cell apoptosis. Added BP was converted stoichiometrically to the corresponding diphenoquinone indicating the synthetic anti-oxidant effectively decreased oxidative stress through a radical scavenging mechanism. Together, these data indicate that BP has the potential to act as a neuro-protective drug.

Chronic treatment with tempol does not significantly ameliorate renal tissue hypoxia or disease progression in a rodent model of polycystic kidney disease

Publisher: Wiley

Date: 29-10-2012

DOI: 10.1111/1440-1681.12013

Abstract: In the present study, we tested whether polycystic kidney disease (PKD) is associated with renal tissue hypoxia and oxidative stress, which, in turn, contribute to the progression of cystic disease and hypertension. Lewis polycystic kidney (LPK) rats and Lewis control (Lewis) rats were treated with tempol (1 mmol/L in drinking water) from 3 to 13 weeks of age or remained untreated. The LPK rats developed polyuria, uraemia and proteinuria. At 13 weeks of age, LPK rats had greater mean arterial pressure (1.5-fold), kidney weight (sixfold) and plasma creatinine (3.5-fold) than Lewis rats. Kidneys from LPK rats were cystic and fibrotic. Renal hypoxia was evidenced by staining for pimonidazole adducts and hypoxia-inducible factor (HIF)-1α in cells lining renal cysts and upregulation of HIF-1α and its downstream targets vascular endothelial growth factor (VEGF), glucose transporter-1 (Glut-1) and heme oxygenase 1 (HO-1). However, total HO activity did not differ greatly between kidney tissue from LPK compared with Lewis rats. Renal oxidative and/or nitrosative stress was evidenced by ninefold greater immunofluorescence for 3-nitrotyrosine in kidney tissue from LPK compared with Lewis rats and a > 10-fold upregulation of mRNA for p47phox and gp91phox. Total renal superoxide dismutase (SOD) activity was sevenfold less and expression of SOD1 mRNA was 70% less in kidney tissue from LPK compared with Lewis rats. In LPK rats, tempol treatment reduced immunofluorescence for 3-nitrotyrosine and HIF1A mRNA while upregulating VEGF and p47phox mRNA expression, but otherwise had little impact on disease progression, renal tissue hypoxia or hypertension. Our findings do not support the hypothesis that oxidative stress drives hypoxia and disease progression in PKD.

Corrigendum to “Cosupplementation with a synthetic, lipid-soluble polyphenol and vitamin C inhibits oxidative damage and improves vascular function yet does not inhibit acute renal injury in an animal model of rhabdomyolysis” [Free Radic. Biol. Med. 52(9) (2012) 1918–1928](S0891584912000883)(10.1016/j.freeradbiomed.2012.02.011)

Publisher: Elsevier BV

Date: 12-2018

DOI: 10.1016/J.FREERADBIOMED.2018.09.006

The Cyclic Nitroxide TEMPOL Ameliorates Oxidative Stress but Not Inflammation in a Cell Model of Parkinson’s Disease

Publisher: MDPI AG

Date: 28-01-2022

DOI: 10.3390/ANTIOX11020257

Abstract: The cyclic nitroxide TEMPOL exerts anti-oxidative and anti-inflammatory effects, and thus may provide therapeutic benefit in Parkinson’s disease (PD), in which mitochondrial dysfunction, oxidative damage and inflammation have been implicated as pathophysiological mechanisms underlying the selective loss of dopaminergic neurons. Markers of oxidative stress and inflammation were investigated in a cell model of differentiated human neuroblastoma (SH-SY5Y) cells treated with the neurotoxin, 6-hydroxydopamine (6-OHDA). Treatment with TEMPOL ameliorated 6-OHDA-mediated cytotoxicity and attenuated biomarkers of oxidative stress including: mitochondrial superoxide anion free radical production, lipid peroxidation, induction of heme oxygenase 1 (HO-1) protein expression and NFκB activation. Treatment with TEMPOL abated decreased gene expression of DRD2S and DRD2L induced by 6-OHDA indicating that TEMPOL may prevent mitochondrial dysfunction and activation of pathways that result in receptor desensitization. 6-OHDA insult decreased gene expression of the antioxidant, SOD-1, and this diminution was also mitigated by TEMPOL. Activation of NFκB increased pro-inflammatory IFNy and decreased IL-6, however, TEMPOL had no effect on these inflammation mediators. Overall, this data suggests that cyclic nitroxides may preserve dopaminergic neuronal cell viability by attenuating oxidative stress and mitochondrial dysfunction, but are unable to affect inflammatory mediators that propagate cellular damage and neurodegeneration in PD.

Synthetic cathinones induce cell death in dopaminergic SH-SY5Y cells via stimulating mitochondrial dysfunction

Publisher: MDPI AG

Date: 18-02-2020

DOI: 10.3390/IJMS21041370

Abstract: Increasing reports of neurological and psychiatric complications due to psychostimulant synthetic cathinones (SCs) have recently raised public concern. However, the precise mechanism of SC toxicity is unclear. This paucity of understanding highlights the need to investigate the in-vitro toxicity and mechanistic pathways of three SCs: butylone, pentylone, and 3,4-Methylenedioxypyrovalerone (MDPV). Human neuronal cells of SH-SY5Y were cultured in supplemented DMEM/F12 media and differentiated to a neuronal phenotype using retinoic acid (10 μM) and 12-O-tetradecanoylphorbol-13-acetate (81 nM). Trypan blue and lactate dehydrogenase assays were utilized to assess the neurotoxicity potential and potency of these three SCs. To investigate the underlying neurotoxicity mechanisms, measurements included markers of oxidative stress, mitochondrial bioenergetics, and intracellular calcium (Ca2+), and cell death pathways were evaluated at two doses (EC15 and EC40), for each drug tested. Following 24 h of treatment, all three SCs exhibited a dose-dependent neurotoxicity, characterized by a significant (p 0.0001 vs. control) production of reactive oxygen species, decreased mitochondrial bioenergetics, and increased intracellular Ca2+ concentrations. The activation of caspases 3 and 7 implicated the orchestration of mitochondrial-mediated neurotoxicity mechanisms for these SCs. Identifying novel therapeutic agents to enhance an altered mitochondrial function may help in the treatment of acute-neurological complications arising from the illicit use of these SCs.

The endothelium-derived hyperpolarizing factor, H2O2, promotes metal-ion efflux in aortic endothelial cells: Elemental mapping by a hard X-ray microprobe

Publisher: American Chemical Society (ACS)

Date: 23-09-2006

DOI: 10.1021/BI0604375

Abstract: Hydrogen peroxide (H(2)O(2)) is a physiologic oxidant implicated in vascular cell signaling, although little is known about the biochemical consequences of its reaction with endothelial cells. Submicrometer-resolution hard X-ray elemental mapping of cultured porcine aortic endothelial cells (PAEC) has provided data on the global changes for intracellular elemental density within PAEC and indicates an efflux of metal ions and phosphorus from the cytoplasm after H(2)O(2) treatment. The synchrotron-radiation-induced X-ray emission experiments (SRIXE) show that H(2)O(2)-treated cells are irregularly shaped and exhibit blebbing indicative of increased permeability due to the damaged membrane. The SRIXE results suggest that H(2)O(2)-induced damage is largely restricted to the cell membrane as judged by the changes to membrane and cytoplasmic components rather than the cell nucleus. The SRIXE data also provide a mechanism for cell detoxification as the metal-ion efflux resulting from the initial H(2)O(2)-mediated changes to cell membrane potentially limits intracellular metal-mediated redox processes through Fenton-like chemistry. They may also explain the increased levels of these ions in atherosclerotic plaques, regardless of whether they are involved in plaque formation. Finally, the SRIXE data support the notion that cultured endothelial cells exposed to H(2)O(2) respond with enhanced cellular metal-ion efflux into the extracellular space.

The Peroxidase Activity of a Hemin−DNA Oligonucleotide Complex:  Free Radical Damage to Specific Guanine Bases of the DNA

Publisher: American Chemical Society (ACS)

Date: 30-01-2001

DOI: 10.1021/JA0023534

Abstract: A specific DNA oligonucleotide--hemin complex (PS2.M--hemin complex) that exhibits DNA-enhanced peroxidative activity was studied by EPR and UV--visible spectroscopy and by chemical probing analysis. EPR data obtained from low-temperature experiments on the PS2.M--hemin complex showed both a low-field g approximately 6 and a high-field g approximately 2 signal. These EPR signals are typical of high-spin ferric heme with axial symmetry as judged by the EPR spectrum of six-coordinate heme iron in acidic Fe(III)-myoglobin. This similarity is consistent with the presence of two axial ligands to the heme iron within the PS2.M--hemin complex, one of which is a water molecule. Optical analyses of the acid-base transition for the hemin complex yielded a pK(a) value for the water ligand of 8.70 +/- 0.03 (mean +/- SD). Low-temperature EPR analysis coupled with parallel spin-trapping investigations following the reaction of the PS2.M--hemin complex and hydrogen peroxide (H(2)O(2)) indicated the formation of a carbon-centered radical, most likely on the PS2.M oligonucleotide. Chemical probing analysis identified specific guanine bases within the PS2.M sequence that underwent oxidative damage upon reaction with H(2)O(2). These and other experimental findings support the hypothesis that the interaction of specific guanines of PS2.M with the bound hemin cofactor might contribute to the superior peroxidative activity of the PS2.M--hemin complex.

Cytosolic phospholipase A2α sustains pAKT, pERK and AR levels in PTEN-null/mutated prostate cancer cells

Publisher: Elsevier BV

Date: 06-2013

DOI: 10.1016/J.BBALIP.2013.02.011

Abstract: Constitutive phosphorylation of protein kinase B (AKT) is a common feature of cancer caused by genetic alteration in the phosphatase and tensin homolog (PTEN) gene and is associated with poor prognosis. This study determined the role of cytosolic phospholipase A2α (cPLA2α) in AKT, extracellular signal-regulated kinase (ERK) and androgen receptor (AR) signaling in PTEN-null/mutated prostate cancer cells. Doxycycline (Dox)-induced expression of cPLA2α led to an increase in pAKT, pGSK3β and cyclin D1 levels in LNCaP cells that possess a PTEN frame-shift mutation. In contrast, silencing cPLA2α expression with siRNA decreased pAKT, pGSK3β and cyclin D1 levels in both PC-3 (PTEN deletion) and LNCaP cells. Silencing of cPLA2α decreased pERK and AR protein levels. The inhibitory effect of cPLA2α siRNA on pAKT and AR protein levels was reduced by the addition of arachidonic acid (AA), whereas the stimulatory effect of AA on pAKT, pERK and AR levels was decreased by an inhibitor of 5-hydroxyeicosatetraenoic acid production. Pharmacological blockade of cPLA2α with Efipladib reduced pAKT and AR levels with a concomitant inhibition of PC-3 and LNCaP cell proliferation. These results demonstrate an important role for cPLA2α in sustaining AKT, ERK and AR signaling in PTEN-null/mutated prostate cancer cells and provide a potential molecular target for treating prostate cancer.

University Of Sydney

Location: Australia

View Organisation

Oxidative Stress Bioanalytical Facility

Start Date: 2010

End Date: 2010

Funder: Australian Research Council

The Mode Of Action Of The Haem Protein Neuroglobin In Protecting Nerve Cells

Start Date: 2013

End Date: 2015

Funder: Australian Research Council

Biochemical Properties Of S-nitroso-myoglobin And Its Role In Regulating Nitric Oxide Bio-availability

Start Date: 2003

End Date: 2007

Funder: Australian Research Council

Cellular Response To Pro-oxidative Myoglobin

Start Date: 2008

End Date: 2010

Funder: Australian Research Council

L-Band EPR Spectrometer.

Start Date: 2002

End Date: 2005

Funder: Wellcome Trust

The Fate Of Dietary Selenium In Vivo; A Direct Approach To Linking Chemical Form With Biological Activity

Start Date: 2009

End Date: 2013

Funder: Australian Research Council

Novel Vitamin E Analogues With Enhanced Specificity For Malignant Cells

Start Date: 2004

End Date: 2006

Funder: Australian Research Council

Distribution Of Tissue Proteins, Elemental Ions And Nanoparticles

Start Date: 2016

End Date: 2018

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0453372

Start Date: 2004

End Date: 12-2007

Amount: $210,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0878559

Start Date: 02-2008

End Date: 12-2010

Amount: $420,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP200102670

Start Date: 2020

End Date: 12-2024

Amount: $460,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0343325

Start Date: 2003

End Date: 11-2007

Amount: $700,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0985807

Start Date: 2009

End Date: 06-2015

Amount: $810,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE100100125

Start Date: 06-2010

End Date: 12-2010

Amount: $330,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP160102063

Start Date: 2016

End Date: 07-2019

Amount: $345,100.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP130103711

Start Date: 02-2013

End Date: 02-2016

Amount: $265,000.00

Funder: Australian Research Council