ORCID Profile
0000-0002-0898-875X
Current Organisation
Monash University
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Bioinorganic Chemistry | Inorganic Chemistry | Biochemistry and Cell Biology | Receptors and Membrane Biology | Structural Biology (incl. Macromolecular Modelling) | Biologically Active Molecules | Nanochemistry and Supramolecular Chemistry
Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Biological Sciences |
Publisher: Mary Ann Liebert Inc
Date: 05-2016
Publisher: Springer International Publishing
Date: 2018
Publisher: Springer Science and Business Media LLC
Date: 17-02-2021
DOI: 10.1038/S42003-021-01740-Y
Abstract: The endosomal system provides rich signal processing capabilities for responses elicited by growth factor receptors and their ligands. At the single cell level, endosomal trafficking becomes a critical component of signal processing, as exemplified by the epidermal growth factor (EGF) receptors. Activated EGFRs are trafficked to the phosphatase-enriched peri-nuclear region (PNR), where they are dephosphorylated and degraded. The details of the mechanisms that govern the movements of stimulated EGFRs towards the PNR, are not completely known. Here, exploiting the advantages of lattice light-sheet microscopy, we show that EGFR activation by EGF triggers a transient calcium increase causing a whole-cell level redistribution of Adaptor Protein, Phosphotyrosine Interacting with PH Domain And Leucine Zipper 1 (APPL1) from pre-existing endosomes within one minute, the rebinding of liberated APPL1 directly to EGFR, and the dynein-dependent translocation of APPL1-EGF-bearing endosomes to the PNR within ten minutes. The cell spanning, fast acting network that we reveal integrates a cascade of events dedicated to the cohort movement of activated EGF receptors. Our findings support the intriguing proposal that certain endosomal pathways have shed some of the stochastic strategies of traditional trafficking and have evolved processes that provide the temporal predictability that typify canonical signaling.
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.FREERADBIOMED.2018.03.008
Abstract: Here we describe new fluorescent probes based on fluorescein and rhodamine that provide reversible, real-time insight into cellular redox status. The new probes incorporate bio-imaging relevant fluorophores derived from fluorescein and rhodamine linked with stable nitroxide radicals such that they cannot be cleaved, either spontaneously or enzymatically by cellular processes. Overall fluorescence emission is determined by reversible reduction and oxidation, hence the steady state emission intensity reflects the balance between redox potentials of critical redox couples within the cell. The permanent positive charge on the rhodamine-based probes leads to their rapid localisation within mitochondria in cells. Reduction and oxidation also leads to marked changes in the fluorophore lifetime, enabling monitoring by fluorescence lifetime imaging microscopy. Finally, we demonstrate that administration of a methyl ester version of the rhodamine-based probe can be used at concentrations as low as 5 nM to generate a readily detected response to redox stress within cells as analysed by flow cytometry.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2CC01825J
Abstract: β-Galactosidase triggered theranostic Gal-CGem is activated selectively in hepatic carcinoma cells HepG2 to monitor real-time assays of gemcitabine formation.
Publisher: American Chemical Society (ACS)
Date: 15-08-2023
Publisher: American Chemical Society (ACS)
Date: 18-06-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1CB00128K
Abstract: New naphthalimide tetrazine probes permit fluorescent imaging of biomolecules in vitro and in living cells. They can be modified to provide previously unknown information about health and disease in biological systems.
Publisher: Cold Spring Harbor Laboratory
Date: 29-11-2018
DOI: 10.1101/481796
Abstract: Multicellular life processes such as proliferation and differentiation depend on cell surface signaling receptors that bind ligands generally referred to as growth factors. Recently, it has emerged that the endosomal system provides rich signal processing capabilities for responses elicited by these factors [1-3]. At the single cell level, endosomal trafficking becomes a critical component of signal processing, as exemplified by the epidermal growth factor (EGF) receptors of the receptor tyrosine kinase family. EGFRs, once activated by EGF, are robustly trafficked to the phosphatase-enriched peri-nuclear region (PNR), where they are dephosphorylated [4-8]. However, the details of the mechanisms regulating the movements of stimulated EGFR in time and space, i.e., towards the PNR, are not known. What endosomal regulators provide specificity to EGFR? Do modifications to the receptor upon stimulation regulate its trafficking? To understand the events leading to EGFR translocation, and especially the early endosomal dynamics that immediately follow EGFR internalization, requires the real-time, long-term, whole-cell imaging of multiple elements. Here, exploiting the advantages of lattice light-sheet microscopy [9], we show that the binding of EGF by its receptor, EGFR, triggers a transient calcium increase that peaks by 30 s, causing the desorption of APPL1 from pre-existing endosomes within one minute, the rebinding of liberated APPL1 to EGFR within three minutes, and the dynein-dependent translocation of APPL1-EGF-bearing endosomes to the PNR within five minutes. The novel, cell spanning, fast acting network that we reveal integrates a cascade of events dedicated to the cohort movement of activated EGFR receptors. Our findings support the intriguing proposal that certain endosomal pathways have shed some of the stochastic strategies of traditional trafficking, and have evolved behaviors whose predictability is better suited to signaling [10, 11]. Work presented here demonstrates that our whole cell imaging approach can be a powerful tool in revealing critical transient interactions in key cellular processes such as receptor trafficking.
Publisher: Wiley
Date: 20-01-2022
Abstract: Many soluble proteins can self‐assemble into macromolecular structures called amyloids, a subset of which are implicated in a range of neurodegenerative disorders. The nanoscale size and structural heterogeneity of prefibrillar and early aggregates, as well as mature amyloid fibrils, pose significant challenges for the quantification of amyloid morphologies. We report a fluorescent amyloid sensor AmyBlink‐1 and its application in super‐resolution imaging of amyloid structures. AmyBlink‐1 exhibits a 5‐fold increase in ratio of the green (thioflavin T) to red (Alexa Fluor 647) emission intensities upon interaction with amyloid fibrils. Using AmyBlink‐1 , we performed nanoscale imaging of four different types of amyloid fibrils, achieving a resolution of ≈30 nm. AmyBlink‐1 enables nanoscale visualization and subsequent quantification of morphological features, such as the length and skew of in idual amyloid aggregates formed at different times along the amyloid assembly pathway.
Publisher: American Chemical Society (ACS)
Date: 26-06-2023
DOI: 10.26434/CHEMRXIV-2023-SQ6GZ
Abstract: Self-assembly of misfolded proteins can lead to the formation of amyloids, which are implicated in the onset of many pathologies including Alzheimer’s disease and Parkinson’s disease. The facile detection and discrimination of different amyloids is crucial for early diagnosis of amyloid-related pathologies. Here, we report the development of a fluorescent two-sensor array which is able to correctly discriminate between four different amyloids implicated in amyloid-related pathologies with 100% classification. The array was also applied to mouse models of Alzheimer’s disease and was able to discriminate between s les from mice corresponding to early (6 months) and advanced (12 months) stages of Alzheimer’s disease. Finally, the flexibility of the array was assessed by expanding the analytes to include functional amyloids. The same two-sensor array was able to correctly discriminate between eight different disease-associated and functional amyloids with 100% classification.
Publisher: American Chemical Society (ACS)
Date: 02-08-2017
DOI: 10.1021/ACS.INORGCHEM.7B01368
Abstract: Dense tumors are resistant to conventional chemotherapies due to the unique tumor microenvironment characterized by hypoxic regions that promote cellular dormancy. Bioreductive drugs that are activated in response to this hypoxic environment are an attractive strategy for therapy with anticipated lower harmful side effects in normoxic healthy tissue. Cobalt bioreductive pro-drugs that selectively release toxic payloads upon reduction in hypoxic cells have shown great promise as anticancer agents. However, the bioreductive response in the tumor microenvironment must be better understood, as current techniques for monitoring bioreduction to Co(II) such as X-ray absorption near-edge structure and extended X-ray absorption fine structure provide limited information on speciation and require synchrotron radiation sources. Here, we present magnetic resonance imaging (MRI) as an accessible and powerful technique to monitor bioreduction by treating the cobalt complex as an MRI contrast agent and monitoring the change in water signal induced by reduction from diamagnetic Co(III) to paramagnetic Co(II). Cobalt pro-drugs built upon the tris(2-pyridylmethyl)amine ligand scaffold with varying charge were investigated for distribution and activity in a 3D tumor spheroid model by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and MRI. In addition, paramagnetic
Publisher: Wiley
Date: 10-05-2017
Abstract: Early endosomes are dynamic intracellular compartments that fuse with incoming endocytic carrier vesicles and associated cargoes from the plasma membrane. It has been long known that the chemical structures of lipids confer striking properties and rich biochemistry on bilayers. Although the organisational principles of the plasma membrane are relatively better understood, understanding endosomal membranes has been challenging. It has become increasingly apparent that endosomal membranes, because of their lipid compositions and interactions, use distinct lipid chemistries. We discuss the biochemical and biophysical phenomena in play at the early endosomal membrane. We focus on cholesterol, phosphoinositides, and phosphatidylserine and their clear roles in endosome functions. We discuss the various principles and mechanisms underpinning how these lipids are implicated at the functional level in the working of endosomes, and we summarise early endosomes as a multimodal organelle employing distinct lipid-specific mechanisms.
Publisher: Wiley
Date: 20-01-2022
Abstract: Many soluble proteins can self‐assemble into macromolecular structures called amyloids, a subset of which are implicated in a range of neurodegenerative disorders. The nanoscale size and structural heterogeneity of prefibrillar and early aggregates, as well as mature amyloid fibrils, pose significant challenges for the quantification of amyloid morphologies. We report a fluorescent amyloid sensor AmyBlink‐1 and its application in super‐resolution imaging of amyloid structures. AmyBlink‐1 exhibits a 5‐fold increase in ratio of the green (thioflavin T) to red (Alexa Fluor 647) emission intensities upon interaction with amyloid fibrils. Using AmyBlink‐1 , we performed nanoscale imaging of four different types of amyloid fibrils, achieving a resolution of ≈30 nm. AmyBlink‐1 enables nanoscale visualization and subsequent quantification of morphological features, such as the length and skew of in idual amyloid aggregates formed at different times along the amyloid assembly pathway.
Publisher: Wiley
Date: 17-11-2023
Abstract: Decoding cellular processes requires visualization of the spatial distribution and dynamic interactions of biomolecules. It is therefore not surprising that innovations in imaging technologies have facilitated advances in biomedical research. The advent of super‐resolution imaging technologies has empowered biomedical researchers with the ability to answer long‐standing questions about cellular processes at an entirely new level. Fluorescent probes greatly enhance the specificity and resolution of super‐resolution imaging experiments. Here, we introduce key super‐resolution imaging technologies, with a brief discussion on single‐molecule localization microscopy (SMLM). We evaluate the chemistry and photochemical mechanisms of fluorescent probes employed in SMLM. This Review provides guidance on the identification and adoption of fluorescent probes in single molecule localization microscopy to inspire the design of next‐generation fluorescent probes amenable to single‐molecule imaging.
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CC03464C
Abstract: A fluorescent sensor for redox state shows reversible oxidation/reduction at biologically-relevant potentials, and is used to visualise cellular oxidative capacity.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8PY00703A
Abstract: Molecular polymer brushes allow for independent tailoring of nanoparticle design parameters. Brush particles with altered shape and aspect ratio revealed that particle shape effects may be decoupled from surface chemistry to achieve higher tumour spheroid interaction and penetration.
Publisher: Elsevier BV
Date: 2018
DOI: 10.1016/J.ACTBIO.2017.10.028
Abstract: In this study, the Cu-doping mechanism of Biphasic Calcium Phosphate (BCP) was thoroughly investigated, as was its ionic release behavior, in order to elucidate cytotoxicity features of these bioceramics. BCP are composed of hydroxyapatite (Ca Biphasic Calcium Phosphates (BCP) are bioceramics composed of hydroxyapatite (HAp, Ca
Publisher: American Chemical Society (ACS)
Date: 10-03-2023
DOI: 10.26434/CHEMRXIV-2023-5SHBN
Abstract: Lipid droplets are essential for cellular lipid storage, playing critical roles in cellular lipid metabolism. Although lipid droplets have drawn intense research in recent years, much remains to be uncovered about the roles of this organelle in biology. Lipid droplet indicators exhibiting large Stokes shifts and improved brightness are therefore in demand. We report two asymmetric BODIPY derivatives, BoL1 and BoL2 bearing a benzothiazole group at the 6-position, which led to bathochromic shifts of 62 nm for BoL1 and 37 nm for BoL2 in fluorescence emission when compared to the reference molecules without the benzothiazole group. The incorporation of the benzothiazole moiety also resulted in a large Stokes shift of 40 nm. BoL1 and BoL2 have been demonstrated to operate as lipid droplet indicators in both confocal and STED imaging. BoL2 showed particularly good cellular retention and was further applied to explore the impact of cellular starvation on the trafficking of lipid droplets.
Publisher: Springer Science and Business Media LLC
Date: 03-04-2020
DOI: 10.1186/S12860-020-00256-3
Abstract: Progesterone Receptor Membrane Component 1 (PGRMC1) is expressed in many cancer cells, where it is associated with detrimental patient outcomes. It contains phosphorylated tyrosines which evolutionarily preceded deuterostome gastrulation and tissue differentiation mechanisms. We demonstrate that manipulating PGRMC1 phosphorylation status in MIA PaCa-2 (MP) cells imposes broad pleiotropic effects. Relative to parental cells over-expressing hemagglutinin-tagged wild-type (WT) PGRMC1-HA, cells expressing a PGRMC1-HA-S57A/S181A double mutant (DM) exhibited reduced levels of proteins involved in energy metabolism and mitochondrial function, and altered glucose metabolism suggesting modulation of the Warburg effect. This was associated with increased PI3K/AKT activity, altered cell shape, actin cytoskeleton, motility, and mitochondrial properties. An S57A/Y180F/S181A triple mutant (TM) indicated the involvement of Y180 in PI3K/AKT activation. Mutation of Y180F strongly attenuated subcutaneous xenograft tumor growth in NOD-SCID gamma mice. Elsewhere we demonstrate altered metabolism, mutation incidence, and epigenetic status in these cells. Altogether, these results indicate that mutational manipulation of PGRMC1 phosphorylation status exerts broad pleiotropic effects relevant to cancer and other cell biology.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5OB00928F
Abstract: NpFR2 is a fluorescent sensor that can reversibly measure changes in the mitochondrial redox environment.
Publisher: Wiley
Date: 02-12-2016
Abstract: The redox chemistry of the cell is key to its function and health, and the development of chemical tools to study redox biology is important. While fluxes in oxidative state are essential for healthy cell function, a chronically elevated oxidative capacity is linked to disease. It is therefore essential that probes of biological redox states distinguish between these two conditions by the reversible sensing of changes over time. In this review, we discuss the current progress towards such probes, and identify key directions for future research in this nascent field of vital biological interest.
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3TB21397H
Publisher: Mary Ann Liebert Inc
Date: 05-2016
Abstract: Recent research has identified key roles for reactive oxygen species (ROS)/reactive nitrogen species (RNS) in redox signaling, but much remains to be uncovered. Molecular imaging tools to study these processes must not only be selective to enable identification of the ROS/RNS involved but also reversible to distinguish signaling processes from oxidative stress. Fluorescent sensors offer the potential to image such processes with high spatial and temporal resolution. A broad array of strategies has been developed that enable the selective sensing of ROS/RNS. More recently, attention has turned to the design of reversible small-molecule sensors of global redox state, with a further set of probes capable of reversible sensing of in idual ROS/RNS. In this study, we discuss the key challenges in achieving simultaneous detection of reversible oxidative bursts with unambiguous determination of a particular ROS/RNS. We have highlighted key design features of small-molecule probes that show promise in enabling the study of redox signaling, identifying essential parameters that must be assessed for any new probe. Antioxid. Redox Signal. 24, 713-730.
Publisher: Cold Spring Harbor Laboratory
Date: 11-11-2018
DOI: 10.1101/464586
Abstract: Tuberculosis is a chronic inflammatory disease caused by persistent infection with Mycobacterium tuberculosis. The rise of antibiotic resistant strains necessitates the design of novel treatments. Recent evidence shows that not only is M. tuberculosis highly resistant to oxidative killing, it also co-opts host oxidant production to induce phagocyte death facilitating bacterial dissemination. We have targeted this redox environment with the cyclic nitroxide derivative 4-methoxy-TEMPO (MetT) in the zebrafish-M. marinum infection model. MetT inhibited the production of mitochondrial ROS and decreased infection-induced cell death to aid containment of infection. We identify a second mechanism of action whereby stress conditions, including hypoxia, found in the infection microenvironment appear to sensitise M. marinum to killing by MetT both in vitro and in vivo. Together, our study demonstrates MetT inhibited the growth and dissemination of M. marinum through host and bacterial targets.
Publisher: Oxford University Press (OUP)
Date: 2016
DOI: 10.1039/C6MT00083E
Abstract: Ratiometric probe for Cu( i ) reveals influence of cisplatin on mitochondrial copper homeostasis.
Publisher: Cambridge University Press (CUP)
Date: 21-09-2021
DOI: 10.33774/CHEMRXIV-2021-HHJVC
Abstract: Many soluble proteins can self-assemble into macromolecular structures called amyloids, a subset of which are implicated in a range of neurodegenerative disorders. The nanoscale size and structural heterogeneity of prefibrillar and early aggregates, as well as mature amyloid fibrils, pose significant challenges for the quantification of amyloid species, identification of their cellular interaction partners and for elucidation of the molecular basis for cytotoxicity. We report a fluorescent amyloid sensor AmyBlink-1 and its application in super-resolution imaging of amyloid structures. AmyBlink-1 exhibits a 5-fold increase in ratio of the green (thioflavin T) to red (Alexa Fluor 647) emission intensities upon interaction with amyloid fibrils. Using AmyBlink-1, we performed nanoscale imaging of four different types of amyloid fibrils, achieving a resolution of ~30 nm. AmyBlink-1 enables molecular-level visualization and subsequent quantification of morphological features, such as the length and skew of in idual amyloid aggregates formed at different times along the amyloid assembly pathway.
Publisher: Elsevier BV
Date: 03-2017
DOI: 10.1016/J.ACTBIO.2016.12.011
Abstract: Biphasic calcium phosphates (BCPs) are bioceramics composed of hydroxyapatite (HAp, Ca Biphasic calcium phosphates (BCPs) are bioceramics composed of hydroxyapatite (HAp, Ca
Publisher: Wiley
Date: 22-06-2017
Abstract: The use of fluorescent markers and probes greatly enhances biological investigations but relies on the provision of an array of fluorophores with erse properties. Herein we report a novel carborane-containing coumarin, 5, which is sufficiently lipophilic to localise in cellular lipid droplets. In non-polar solvents which show comparable polarities to those of a lipid environment, compound 5 exhibits a fluorescence quantum yield two orders of magnitude greater than found in aqueous solvents, adding a further degree of selectivity to lipid droplet imaging. Compound 5 can stain lipid droplets in ex vivo adipocytes as well as in cultured cells, and can be utilised in flow cytometry as well as confocal microscopy.
Publisher: Wiley
Date: 24-07-2023
Abstract: Lipid droplets are essential for cellular lipid storage, playing critical roles in cellular lipid metabolism. Although lipid droplets have drawn intense research in recent years, much remains to be uncovered about the roles of this organelle in biology. Lipid droplet indicators exhibiting large Stokes shifts and improved brightness are therefore in demand. We report two asymmetric BODIPY derivatives, BoL1 and BoL2 bearing a benzothiazole group at the 6‐position, which led to bathochromic shifts of 62 nm for BoL1 and 37 nm for BoL2 in fluorescence emission when compared to the reference molecules without the benzothiazole group. The incorporation of the benzothiazole moiety also resulted in a large Stokes shift of 40 nm. BoL1 and BoL2 have been demonstrated to operate as lipid droplet indicators in both confocal and STED imaging. BoL2 showed particularly good cellular retention and was further applied to explore the impact of cellular starvation on the trafficking of lipid droplets.
Publisher: American Chemical Society (ACS)
Date: 21-09-2021
DOI: 10.26434/CHEMRXIV-2021-HHJVC
Abstract: Many soluble proteins can self-assemble into macromolecular structures called amyloids, a subset of which are implicated in a range of neurodegenerative disorders. The nanoscale size and structural heterogeneity of prefibrillar and early aggregates, as well as mature amyloid fibrils, pose significant challenges for the quantification of amyloid species, identification of their cellular interaction partners and for elucidation of the molecular basis for cytotoxicity. We report a fluorescent amyloid sensor AmyBlink-1 and its application in super-resolution imaging of amyloid structures. AmyBlink-1 exhibits a 5-fold increase in ratio of the green (thioflavin T) to red (Alexa Fluor 647) emission intensities upon interaction with amyloid fibrils. Using AmyBlink-1, we performed nanoscale imaging of four different types of amyloid fibrils, achieving a resolution of ~30 nm. AmyBlink-1 enables molecular-level visualization and subsequent quantification of morphological features, such as the length and skew of in idual amyloid aggregates formed at different times along the amyloid assembly pathway.
Publisher: American Chemical Society (ACS)
Date: 06-07-2020
Publisher: Wiley
Date: 05-07-2019
DOI: 10.1002/JCTB.6104
Publisher: American Chemical Society (ACS)
Date: 31-01-2019
DOI: 10.1021/ACSCHEMBIO.9B00063
Abstract: Stapled peptides have great potential as modulators of protein-protein interactions (PPIs). However, there is a vast landscape of chemical features that can be varied for any given peptide, and identifying a set of features that maximizes cellular uptake and subsequent target engagement remains a key challenge. Herein, we present a systematic analysis of staple functionality on the peptide bioactivity landscape in cellular assays. Through application of a "toolbox" of ersified dialkynyl linkers to the stapling of MDM2-binding peptides via a double-click approach, we conducted a study of cellular uptake and p53 activation as a function of the linker. Minor changes in the linker motif and the specific pairing of linker with peptide sequence can lead to substantial differences in bioactivity, a finding which may have important design implications for peptide-based inhibitors of other PPIs. Given the complexity of the structure-activity relationships involved, the toolbox approach represents a generalizable strategy for optimization when progressing from in vitro binding assays to cellular efficacy studies.
Publisher: Wiley
Date: 27-10-2023
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.FREERADBIOMED.2019.03.010
Abstract: Tuberculosis is a chronic inflammatory disease caused by persistent infection with Mycobacterium tuberculosis. The rise of antibiotic resistant strains necessitates the design of novel treatments. Recent evidence shows that not only is M. tuberculosis highly resistant to oxidative killing, it also co-opts host oxidant production to induce phagocyte death facilitating bacterial dissemination. We have targeted this redox environment with the cyclic nitroxide derivative 4-methoxy-TEMPO (MetT) in the zebrafish-M. marinum infection model. MetT inhibited the production of mitochondrial ROS and decreased infection-induced cell death to aid containment of infection. We identify a second mechanism of action whereby stress conditions, including hypoxia, found in the infection microenvironment appear to sensitise M. marinum to killing by MetT both in vitro and in vivo. Together, our study demonstrates MetT inhibited the growth and dissemination of M. marinum through host and bacterial targets.
Publisher: American Chemical Society (ACS)
Date: 14-02-2019
DOI: 10.1021/ACSCHEMNEURO.9B00015
Abstract: While the roles of intrinsically disordered protein domains in driving interprotein interactions are increasingly well-appreciated, the mechanism of toxicity of disease-causing disordered proteins remains poorly understood. A prime ex le is Alzheimer's disease (AD) associated amyloid beta (Aβ). Aβ oligomers are highly toxic partially structured peptide assemblies with a distinct ordered region (residues ∼10-40) and a shorter disordered region (residues ∼1-9). Here, we investigate the role of this disordered domain and its relation to the ordered domain in the manifestation of toxicity through a set of Aβ fragments and stereoisomers designed for this purpose. We measure their effects on lipid membranes and cultured neurons, probing their toxicity, intracellular distributions, and specific molecular interactions using the techniques of confocal imaging, lattice light sheet imaging, fluorescence lifetime imaging, and fluorescence correlation spectroscopy. Remarkably, we find that neither part-Aβ
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CC03394B
Abstract: A FRET-based, ratiometric redox probe undergoes a fluorescence colour change upon reduction, and can be used to study cellular oxidative capacity using confocal microscopy, fluorescence lifetime imaging and flow cytometry.
Publisher: American Chemical Society (ACS)
Date: 29-06-2023
DOI: 10.26434/CHEMRXIV-2023-5SHBN-V2
Abstract: Lipid droplets are essential for cellular lipid storage, playing critical roles in cellular lipid metabolism. Although lipid droplets have drawn intense research in recent years, much remains to be uncovered about the roles of this organelle in biology. Lipid droplet indicators exhibiting large Stokes shifts and improved brightness are therefore in demand. We report two asymmetric BODIPY derivatives, BoL1 and BoL2 bearing a benzothiazole group at the 6-position, which led to bathochromic shifts of 62 nm for BoL1 and 37 nm for BoL2 in fluorescence emission when compared to the reference molecules without the benzothiazole group. The incorporation of the benzothiazole moiety also resulted in a large Stokes shift of 40 nm. BoL1 and BoL2 have been demonstrated to operate as lipid droplet indicators in both confocal and STED imaging. BoL2 showed particularly good cellular retention and was further applied to explore the impact of cellular starvation on the trafficking of lipid droplets.
Publisher: Cold Spring Harbor Laboratory
Date: 24-08-2019
DOI: 10.1101/737718
Abstract: Progesterone Receptor Membrane Component 1 (PGRMC1) is expressed in many cancer cells, where it is associated with detrimental patient outcomes. It contains phosphorylated tyrosines which evolutionarily preceded deuterostome gastrulation and tissue differentiation mechanisms. Here, we demonstrate that manipulating PGRMC1 phosphorylation status in MIA PaCa-2 (MP) cells imposes broad pleiotropic effects. Relative to parental cells over-expressing hemagglutinin-tagged wild-type (WT) PGRMC1-HA, cells expressing a PGRMC1-HA-S57A/S181A double mutant (DM) exhibited reduced levels of proteins involved in energy metabolism and mitochondrial function, and altered glucose metabolism suggesting modulation of the Warburg effect. This was associated with increased PI3K/Akt activity, altered cell shape, actin cytoskeleton, motility, and mitochondrial properties. An S57A/Y180F/S181A triple mutant (TM) indicated the involvement of Y180 in PI3K/Akt activation. Mutation of Y180F strongly attenuated mouse xenograft tumor growth. An accompanying paper demonstrates altered metabolism, mutation incidence, and epigenetic status in these cells, indicating that PGRMC1 phosphorylation strongly influences cancer biology.
Publisher: Wiley
Date: 17-11-2023
Abstract: Decoding cellular processes requires visualization of the spatial distribution and dynamic interactions of biomolecules. It is therefore not surprising that innovations in imaging technologies have facilitated advances in biomedical research. The advent of super‐resolution imaging technologies has empowered biomedical researchers with the ability to answer long‐standing questions about cellular processes at an entirely new level. Fluorescent probes greatly enhance the specificity and resolution of super‐resolution imaging experiments. Here, we introduce key super‐resolution imaging technologies, with a brief discussion on single‐molecule localization microscopy (SMLM). We evaluate the chemistry and photochemical mechanisms of fluorescent probes employed in SMLM. This Review provides guidance on the identification and adoption of fluorescent probes in single molecule localization microscopy to inspire the design of next‐generation fluorescent probes amenable to single‐molecule imaging.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CC03394B
Abstract: A FRET-based, ratiometric redox probe undergoes a fluorescence colour change upon reduction, and can be used to study cellular oxidative capacity using confocal microscopy, fluorescence lifetime imaging and flow cytometry.
Publisher: American Chemical Society (ACS)
Date: 12-02-2019
DOI: 10.1021/ACS.ACCOUNTS.8B00368
Abstract: The availability of electrons to biological systems underpins the mitochondrial electron transport chain (ETC) that powers living cells. It is little wonder, therefore, that the sufficiency of electron supply is critical to cellular health. Considering mitochondrial redox activity alone, a lack of oxygen (hypoxia) leads to impaired production of adenosine triphosphate (ATP), the major energy currency of the cell, whereas excess oxygen (hyperoxia) is associated with elevated production of reactive oxygen species (ROS) from the interaction of oxygen with electrons that have leaked from the ETC. Furthermore, the redox proteome, which describes the reversible and irreversible redox modifications of proteins, controls many aspects of biological structure and function. Indeed, many major diseases, including cancer and diabetes, are now termed "redox diseases", spurring much interest in the measurement and monitoring of redox states and redox-active species within biological systems. In this Account, we describe recent efforts to develop magnetic resonance (MR) and fluorescence imaging probes for studying redox biology. These two classes of molecular imaging tools have proved to be invaluable in supplementing the structural information that is traditionally provided by MRI and fluorescence microscopy, respectively, with highly sensitive chemical information. Importantly, the study of biological redox processes requires sensors that operate at biologically relevant reduction potentials, which can be achieved by the use of bioinspired redox-sensitive groups. Since oxidation-reduction reactions are so crucial to modulating cellular function and yet also have the potential to damage cellular structures, biological systems have developed highly sophisticated ways to regulate and sense redox changes. There is therefore a plethora of erse chemical structures in cells with biologically relevant reduction potentials, from transition metals to organic molecules to proteins. These chemical groups can be harnessed in the development of exogenous molecular imaging agents that are well-tuned to biological redox events. To date, small-molecule redox-sensitive tools for oxidative stress and hypoxia have been inspired from four classes of cellular regulators. The redox-sensitive groups found in redox cofactors, such as flavins and nicotinamides, can be used as reversible switches in both fluorescent and MR probes. Enzyme substrates that undergo redox processing within the cell can be modified to provide fluorescence or MR readout while maintaining their selectivity. Redox-active first-row transition metals are central to biological homeostasis, and their marked electronic and magnetic changes upon oxidation/reduction have been used to develop MR sensors. Finally, redox-sensitive amino acids, particularly cysteine, can be utilized in both fluorescent and MR sensors.
Start Date: 2018
End Date: 12-2020
Amount: $362,045.00
Funder: Australian Research Council
View Funded ActivityStart Date: 03-2022
End Date: 06-2025
Amount: $552,811.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2021
End Date: 06-2024
Amount: $445,000.00
Funder: Australian Research Council
View Funded Activity