ORCID Profile
0000-0002-0068-9974
Current Organisation
University of Queensland Institute for Molecular Bioscience
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Publisher: Oxford University Press (OUP)
Date: 02-02-2010
DOI: 10.1111/J.1365-2249.2009.04084.X
Abstract: Schistosoma mansoni infection has been associated with protection against allergies. The mechanisms underlying this association may involve regulatory cells and cytokines. We evaluated the immune response induced by the S. mansoni antigens Sm22·6, PIII and Sm29 in a murine model of ovalbumin (OVA)-induced airway inflammation. BALB/c mice were sensitized with subcutaneously injected OVA-alum and challenged with aerolized OVA. Mice were given three doses of the different S. mansoni antigens. Lung histopathology, cellularity of bronchoalveolar lavage (BAL) and eosinophil peroxidase activity in lung were evaluated. Immunoglobulin (Ig)E levels in serum and cytokines in BAL were also measured. Additionally, we evaluated the frequency of CD4+forkhead box P3 (FoxP3)+ T cells in cultures stimulated with OVA and the expression of interleukin (IL)-10 by these cells. The number of total cells and eosinophils in BAL and the levels of OVA-specific IgE were reduced in the immunized mice. Also, the levels of IL-4 and IL-5 in the BAL of mice immunized with PIII and Sm22·6 were decreased, while the levels of IL-10 were higher in mice immunized with Sm22·6 compared to the non-immunized mice. The frequency of CD4+FoxP3+ T cells was higher in the groups of mice who received Sm22·6, Sm29 and PIII, being the expression of IL-10 by these cells only higher in mice immunized with Sm22·6. We concluded that the S. mansoni antigens used in this study are able to down-modulate allergic inflammatory mediators in a murine model of airway inflammation and that the CD4+FoxP3+ T cells, even in the absence of IL-10 expression, might play an important role in this process.
Publisher: Public Library of Science (PLoS)
Date: 27-03-2014
Publisher: Public Library of Science (PLoS)
Date: 11-11-2011
Publisher: Frontiers Media SA
Date: 24-12-2021
DOI: 10.3389/FPHAR.2021.795455
Abstract: Given the important role of voltage-gated sodium (Na V ) channel-modulating spider toxins in elucidating the function, pharmacology, and mechanism of action of therapeutically relevant Na V channels, we screened the venom from Australian theraphosid species against the human pain target hNa V 1.7. Using assay-guided fractionation, we isolated a 33-residue inhibitor cystine knot (ICK) peptide (Ssp1a) belonging to the NaSpTx1 family. Recombinant Ssp1a (rSsp1a) inhibited neuronal hNa V subtypes with a rank order of potency hNa V 1.7 & 1.6 & 1.2 & 1.3 & 1.1. rSsp1a inhibited hNa V 1.7, hNa V 1.2 and hNa V 1.3 without significantly altering the voltage-dependence of activation, inactivation, or delay in recovery from inactivation. However, rSsp1a demonstrated voltage-dependent inhibition at hNa V 1.7 and rSsp1a-bound hNa V 1.7 opened at extreme depolarizations, suggesting rSsp1a likely interacted with voltage-sensing domain II (VSD II) of hNa V 1.7 to trap the channel in its resting state. Nuclear magnetic resonance spectroscopy revealed key structural features of Ssp1a, including an hipathic surface with hydrophobic and charged patches shown by docking studies to comprise the interacting surface. This study provides the basis for future structure-function studies to guide the development of subtype selective inhibitors.
Publisher: MDPI AG
Date: 30-06-2020
DOI: 10.3390/MD18070343
Abstract: The 27-amino acid (aa)-long δ-conotoxin TxVIA, originally isolated from the mollusc-hunting cone snail Conus textile, slows voltage-gated sodium (NaV) channel inactivation in molluscan neurons, but its mammalian ion channel targets remain undetermined. In this study, we confirmed that TxVIA was inactive on mammalian NaV1.2 and NaV1.7 even at high concentrations (10 µM). Given the fact that invertebrate NaV channel and T-type calcium channels (CaV3.x) are evolutionarily related, we examined the possibility that TxVIA may act on CaV3.x. Electrophysiological characterisation of the native TxVIA on CaV3.1, 3.2 and 3.3 revealed that TxVIA preferentially inhibits CaV3.2 current (IC50 = 0.24 μM) and enhances CaV3.1 current at higher concentrations. In fish bioassays TxVIA showed little effect on zebrafish behaviours when injected intramuscular at 250 ng/100 mg fish. The binding sites for TxVIA at NaV1.7 and CaV3.1 revealed that their channel binding sites contained a common epitope.
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.BBAGEN.2016.07.027
Abstract: Most ant venoms consist predominantly of small linear peptides, although some contain disulfide-linked peptides as minor components. However, in striking contrast to other ant species, some Anochetus venoms are composed primarily of disulfide-rich peptides. In this study, we investigated the venom of the ant Anochetus emarginatus with the aim of exploring these novel disulfide-rich peptides. The venom peptidome was initially investigated using a combination of reversed-phase HPLC and mass spectrometry, then the amino acid sequences of the major peptides were determined using a combination of Edman degradation and de novo MS/MS sequencing. We focused on one of these peptides, U1-PONTX-Ae1a (Ae1a), because of its novel sequence, which we predicted would form a novel 3D fold. Ae1a was chemically synthesized using Fmoc chemistry and its 3D structure was elucidated using NMR spectroscopy. The peptide was then tested for insecticidal activity and its effect on a range of human ion channels. Seven peptides named poneritoxins (PONTXs) were isolated and sequenced. The three-dimensional structure of synthetic Ae1a revealed a novel, compact scaffold in which a C-terminal β-hairpin is connected to the N-terminal region via two disulfide bonds. Synthetic Ae1a reversibly paralyzed blowflies and inhibited human L-type voltage-gated calcium channels (CaV1). Poneritoxins from Anochetus emarginatus venom are a novel class of toxins that are structurally unique among animal venoms. This study demonstrates that Anochetus ant venoms are a rich source of novel ion channel modulating peptides, some of which might be useful leads for the development of biopesticides.
Publisher: Public Library of Science (PLoS)
Date: 09-02-2010
Publisher: Public Library of Science (PLoS)
Date: 05-03-2021
DOI: 10.1371/JOURNAL.PONE.0243645
Abstract: Chemical transfection is broadly used to transiently transfect mammalian cells, although often associated with cellular stress and membrane instability, which imposes challenges for most cellular assays, including high-throughput (HT) assays. In the current study, we compared the effectiveness of calcium phosphate, FuGENE and Lipofectamine 3000 to transiently express two key voltage-gated ion channels critical in pain pathways, Ca V 2.2 and Na V 1.7. The expression and function of these channels were validated using two HT platforms, the Fluorescence Imaging Plate Reader FLIPR Tetra and the automated patch cl QPatch 16X. We found that all transfection methods tested demonstrated similar effectiveness when applied to FLIPR Tetra assays. Lipofectamine 3000-mediated transfection produced the largest peak currents for automated patch cl QPatch assays. However, the FuGENE-mediated transfection was the most effective for QPatch assays as indicated by the superior number of cells displaying GΩ seal formation in whole-cell patch cl configuration, medium to large peak currents, and higher rates of accomplished assays for both Ca V 2.2 and Na V 1.7 channels. Our findings can facilitate the development of HT automated patch cl assays for the discovery and characterization of novel analgesics and modulators of pain pathways, as well as assisting studies examining the pharmacology of mutated channels.
Publisher: American Chemical Society (ACS)
Date: 20-10-2020
Publisher: Elsevier BV
Date: 11-2020
Publisher: Frontiers Media SA
Date: 21-09-2021
DOI: 10.3389/FMOLB.2021.742457
Abstract: Venom peptides are potent and selective modulators of voltage-gated ion channels that regulate neuronal function both in health and in disease. We previously identified the spider venom peptide Tap1a from the Venezuelan tarantula Theraphosa apophysis that targeted multiple voltage-gated sodium and calcium channels in visceral pain pathways and inhibited visceral mechano-sensing neurons contributing to irritable bowel syndrome. In this work, alanine scanning and domain activity analysis revealed Tap1a inhibited sodium channels by binding with nanomolar affinity to the voltage-sensor domain II utilising conserved structure-function features characteristic of spider peptides belonging to family NaSpTx1. In order to speed up the development of optimized Na V -targeting peptides with greater inhibitory potency and enhanced in vivo activity, we tested the hypothesis that incorporating residues identified from other optimized NaSpTx1 peptides into Tap1a could also optimize its potency for Na V s. Applying this approach, we designed the peptides Tap1a-OPT1 and Tap1a-OPT2 exhibiting significant increased potency for Na V 1.1, Na V 1.2, Na V 1.3, Na V 1.6 and Na V 1.7 involved in several neurological disorders including acute and chronic pain, motor neuron disease and epilepsy. Tap1a-OPT1 showed increased potency for the off-target Na V 1.4, while this off-target activity was absent in Tap1a-OPT2. This enhanced potency arose through a slowed off-rate mechanism. Optimized inhibition of Na V channels observed in vitro translated in vivo , with reversal of nocifensive behaviours in a murine model of Na V -mediated pain also enhanced by Tap1a-OPT. Molecular docking studies suggested that improved interactions within loops 3 and 4, and C-terminal of Tap1a-OPT and the Na V channel voltage-sensor domain II were the main drivers of potency optimization. Overall, the rationally designed peptide Tap1a-OPT displayed new and refined structure-function features which are likely the major contributors to its enhanced bioactive properties observed in vivo . This work contributes to the rapid engineering and optimization of potent spider peptides multi-targeting Na V channels, and the research into novel drugs to treat neurological diseases.
Publisher: Frontiers Media SA
Date: 24-08-2023
DOI: 10.3389/FPHAR.2023.1249336
Abstract: Ion channels play a crucial role in erse physiological processes, including neurotransmission and muscle contraction. Venomous creatures exploit the vital function of ion channels by producing toxins in their venoms that specifically target these ion channels to facilitate prey capture upon a bite or a sting. Envenoming can therefore lead to ion channel dysregulation, which for humans can result in severe medical complications that often necessitate interventions such as antivenom administration. Conversely, the discovery of highly potent and selective venom toxins with the capability of distinguishing between different isoforms and subtypes of ion channels has led to the development of beneficial therapeutics that are now in the clinic. This review encompasses the historical evolution of electrophysiology methodologies, highlighting their contributions to venom and antivenom research, including venom-based drug discovery and evaluation of antivenom efficacy. By discussing the applications and advancements in patch-cl techniques, this review underscores the profound impact of electrophysiology in unravelling the intricate interplay between ion channels and venom toxins, ultimately leading to the development of drugs for envenoming and ion channel-related pathologies.
Publisher: Wiley
Date: 02-09-2018
DOI: 10.1111/BPH.13962
Publisher: Cambridge University Press (CUP)
Date: 16-10-2009
DOI: 10.1017/S0031182009991387
Abstract: Proteins associated with the schistosome tegument are of great importance for the development of new intervention strategies since they may be exposed on the surface of the parasite. Herein, we have isolated a cDNA clone encoding for the Schistosoma mansoni SmIg and its recombinant protein was tested as a potential vaccine candidate. Initially, its amino acid sequence was analysed by bioinformatics and shown to possess an N-terminal signal peptide, a C-terminal transmembrane helix, 4 glycosylation sites, an immunoglobulin conserved domain and 73% similarity with a hypothetical S. japonicum protein of unknown function. SmIg was produced by E. coli as a recombinant protein (rSmIg) and its protective effectiveness was evaluated against S. mansoni infection with 100 cercariae in a murine model. Mice immunized with rSmIg induced an immune response characterized by dominant IgG1 isotype and significant levels of IFN-γ, TNF-α, IL-10 and IL-4. Although immunogenic, the recombinant vaccine failed to induce worm burden reduction when compared to the infected control group. However, rSmIg-immunized mice had significant reductions of liver granuloma volume and fibrosis content by 31·8% and 49%, respectively. In conclusion, SmIg is a new tegument protein from S. mansoni that plays an important role in reducing pathology induced by parasite infection.
Publisher: Wiley
Date: 27-06-2017
DOI: 10.1111/BPH.13865
Publisher: American Society for Pharmacology & Experimental Therapeutics (ASPET)
Date: 15-05-2015
Abstract: Spider venoms are a rich source of ion channel modulators with therapeutic potential. Given the analgesic potential of subtype-selective inhibitors of voltage-gated sodium (NaV) channels, we screened spider venoms for inhibitors of human NaV1.7 (hNaV1.7) using a high-throughput fluorescent assay. Here, we describe the discovery of a novel NaV1.7 inhibitor, μ-TRTX-Tp1a (Tp1a), isolated from the venom of the Peruvian green-velvet tarantula Thrixopelma pruriens. Recombinant and synthetic forms of this 33-residue peptide preferentially inhibited hNaV1.7 > hNaV1.6 > hNaV1.2 > hNaV1.1 > hNaV1.3 channels in fluorescent assays. NaV1.7 inhibition was diminished (IC50 11.5 nM) and the association rate decreased for the C-terminal acid form of Tp1a compared with the native amidated form (IC50 2.1 nM), suggesting that the peptide C terminus contributes to its interaction with hNaV1.7. Tp1a had no effect on human voltage-gated calcium channels or nicotinic acetylcholine receptors at 5 μM. Unlike most spider toxins that modulate NaV channels, Tp1a inhibited hNaV1.7 without significantly altering the voltage dependence of activation or inactivation. Tp1a proved to be analgesic by reversing spontaneous pain induced in mice by intraplantar injection in OD1, a scorpion toxin that potentiates hNaV1.7. The structure of Tp1a as determined using NMR spectroscopy revealed a classic inhibitor cystine knot (ICK) motif. The molecular surface of Tp1a presents a hydrophobic patch surrounded by positively charged residues, with subtle differences from other ICK spider toxins that might contribute to its different pharmacological profile. Tp1a may help guide the development of more selective and potent hNaV1.7 inhibitors for treatment of chronic pain.
Publisher: Oxford University Press (OUP)
Date: 21-04-2006
DOI: 10.1111/J.1365-2249.2006.03081.X
Abstract: Surface proteins of schistosomes are exposed to host tissues and thus present as potential candidate molecules for the development of new intervention strategies. Herein, we have identified a new tegumental protein of Schistosoma mansoni, termed Sm29. In silico analysis revealed a signal peptide, three glycosylation sites and a transmembrane region on Sm29 amino acid sequence. Sm29 transcription in mammalian developmental stages cDNA libraries of S. mansoni was verified by PCR using specific primers for Sm29 nucleotide sequence and it revealed the presence of transcripts in schistosomula and adult worm stages of the parasite. Sm29 (40–169) fragment was produced in Escherichia coli and purified by affinity chromatography to be used in the immunological assays. Confocal microscopy confirmed bioinformatic studies, revealing that Sm29 is a membrane-bound protein localized on the tegument of S. mansoni adult worm. ELISA was performed using rSm29 protein to investigate the antibody isotype profile to Sm29 in sera of patients living in endemic areas for schistosomiasis. IgG1 and IgG3 subclass antibodies to rSm29 were predominant in sera of in iduals naturally resistant to infection and resistant to re-infection whereas low levels of IgM, IgA or IgE were measured. Since, IgG1 and IgG3 are involved in parasite killing and in protective immunity the findings reported here suggest the use of Sm29 as a potential candidate vaccine against schistosomiasis.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 21-10-2022
DOI: 10.1097/J.PAIN.0000000000002795
Abstract: The bladder wall is innervated by a complex network of afferent nerves that detect bladder stretch during filling. Sensory signals, generated in response to distension, are relayed to the spinal cord and brain to evoke physiological and painful sensations and regulate urine storage and voiding. Hyperexcitability of these sensory pathways is a key component in the development of chronic bladder hypersensitivity disorders including interstitial cystitis/bladder pain syndrome and overactive bladder syndrome. Despite this, the full array of ion channels that regulate bladder afferent responses to mechanical stimuli have yet to be determined. Here, we investigated the role of low-voltage-activated T-type calcium (Ca V 3) channels in regulating bladder afferent responses to distension. Using single-cell reverse-transcription polymerase chain reaction and immunofluorescence, we revealed ubiquitous expression of Ca V 3.2, but not Ca V 3.1 or Ca V 3.3, in in idual bladder-innervating dorsal root ganglia neurons. Pharmacological inhibition of Ca V 3.2 with TTA-A2 and ABT-639, selective blockers of T-type calcium channels, dose-dependently attenuated ex-vivo bladder afferent responses to distension in the absence of changes to muscle compliance. Further evaluation revealed that Ca V 3.2 blockers significantly inhibited both low- and high-threshold afferents, decreasing peak responses to distension, and delayed activation thresholds, thereby attenuating bladder afferent responses to both physiological and noxious distension. Nocifensive visceromotor responses to noxious bladder distension in vivo were also significantly reduced by inhibition of Ca V 3 with TTA-A2. Together, these data provide evidence of a major role for Ca V 3.2 in regulating bladder afferent responses to bladder distension and nociceptive signalling to the spinal cord.
Publisher: American Chemical Society (ACS)
Date: 07-06-2021
Publisher: MDPI AG
Date: 27-08-2019
Abstract: P hobeteus verdolaga is a recently described Theraphosidae spider from the Andean region of Colombia. Previous reports partially characterized its venom profile. In this study, we conducted a detailed analysis that includes reversed-phase high-performance liquid chromatography (rp-HPLC), calcium influx assays, tandem mass spectrometry analysis (tMS/MS), and venom-gland transcriptome. rp-HPLC fractions of P. verdolaga venom showed activity on CaV2.2, CaV3.2, and NaV1.7 ion channels. Active fractions contained several peptides with molecular masses ranging from 3399.4 to 3839.6 Da. The tMS/MS analysis of active fraction displaying the strongest activity to inhibit calcium channels showed sequence fragments similar to one of the translated transcripts detected in the venom-gland transcriptome. The putative peptide of this translated transcript corresponded to a toxin, here named ω-theraphositoxin-Pv3a, a potential ion channel modulator toxin that is, in addition, very similar to other theraphositoxins affecting calcium channels (i.e., ω-theraphotoxin-Asp1a). Additionally, using this holistic approach, we found that P. verdolaga venom is an important source of disulfide-rich proteins expressing at least eight superfamilies.
Publisher: Oxford University Press (OUP)
Date: 06-07-2016
Abstract: Infection with Schistosoma japonicum causes high levels of pathology that is predominantly determined by the cellular and humoral response of the host. However, the specific antibody response that arises during the development of disease is largely undescribed in Asian schistosomiasis-endemic populations. A schistosome protein microarray was used to compare the antibody profiles of subjects with acute infection, with early or advanced disease associated with severe pathology, with chronic infection, and subjects exposed but stool negative for S. japonicum eggs to the antibody profiles of nonexposed controls. Twenty-five immunodominant antigens were identified, including vaccine candidates, tetraspanin-related proteins, transporter molecules, and unannotated proteins. Additionally, in iduals with severe pathology had a limited specific antibody response, suggesting that in iduals with mild disease may use a broad and strong antibody response, particularly against surface-exposed proteins, to control pathology and/or infection. Our study has identified specific antigens that can discriminate between S. japonicum-exposed groups with different pathologies and may also allow the host to control disease pathology and provide resistance to parasite infection.
Publisher: Elsevier BV
Date: 11-2008
DOI: 10.1016/J.ACTATROPICA.2008.05.023
Abstract: Schistosomiasis continues to be a significant public health problem in tropical countries such as Brazil. Even though drug treatment in endemic areas has been shown to be efficient for controlling morbidity, it does not reduce prevalence due to constant reinfections. Therefore, a long-term disease control strategy is needed combining mass chemotherapy with a protective vaccine. Although the field of vaccine development has experienced more failures than successes, encouraging results have been obtained in recent years using defined recombinant derived Schistosoma mansoni antigens. This article primarily reviews the progress in the development of a vaccine against S. mansoni in Brazil. We discuss here different forms of vaccine tested in Brazil in pre-clinical trials and immunologic studies performed with patients in endemic areas of schistosomiasis. Lastly, we reviewed the S. mansoni genomic projects developed in the country and the recent advances in the identification of new molecules with potential as vaccine targets.
Publisher: Elsevier BV
Date: 03-2007
DOI: 10.1016/J.MICINF.2006.12.004
Abstract: Brucella species are important zoonotic pathogens affecting a wide variety of mammals. Therefore, the identification of new Brucella virulence factors is of great interest in understanding bacterial pathogenesis and immune evasion. In this study, we have identified Brucella abortus vacB gene that presents 2343 nucleotides and 781 amino acids and it shows 39% identity with Shigella flexneri vacB gene that encodes an exoribonuclease RNase R involved in bacterial virulence. Further, we have inactivated Brucella vacB by gene replacement strategy generating a deletion mutant strain. In order to test the role of Brucella vacB in pathogenesis, BALB/c and interferon regulatory factor-1 (IRF-1) knockout (KO) mice received Brucella vacB mutant, the virulent parental strain 2308 or the vaccine strain RB51 and the bacterial CFU numbers in spleens and mous survival were monitored. Our results demonstrated that the B. abortus DeltavacB mutant and the wild type strain 2308 showed similar CFU numbers in BALB/c mice. Additionally, IRF-1 KO mice that received either the vacB mutant or S2308 strain died in 12-14 days postinfection in contrast, all animals that received the RB51 vaccine strain survived for 30 days postinoculation. In summary, this study reports that the vacB gene in B. abortus has no impact on bacterial pathogenesis.
Publisher: Frontiers Media SA
Date: 13-05-2022
Publisher: Frontiers Media SA
Date: 19-06-2019
Publisher: MDPI AG
Date: 29-10-2019
Abstract: Voltage-gated sodium channels (NaVs) are a key determinant of neuronal signalling. Neurotoxins from erse taxa that selectively activate or inhibit NaV channels have helped unravel the role of NaV channels in diseases, including chronic pain. Spider venoms contain the most erse array of inhibitor cystine knot (ICK) toxins (knottins). This review provides an overview on how spider knottins modulate NaV channels and describes the structural features and molecular determinants that influence their affinity and subtype selectivity. Genetic and functional evidence support a major involvement of NaV subtypes in various chronic pain conditions. The exquisite inhibitory properties of spider knottins over key NaV subtypes make them the best lead molecules for the development of novel analgesics to treat chronic pain.
Publisher: Wiley
Date: 03-2010
Abstract: In this study, we have identified a secreted 13 kDa lectin from Mtb (Mtb, Mycobacterium tuberculosis sMTL-13) by homology search of a non-redundant lectin database. Bioinformatic analysis revealed that sMTL-13 belongs to the ricin-type beta-trefoil family of proteins containing a Sec-type signal peptide present in Mtb complex species, but not in non-tuberculous mycobacteria. Following heterologous expression of sMTL-13 and generation of an mAb (clone 276.B7/IgG1kappa), we confirmed that this lectin is present in culture filtrate proteins from Mtb H37Rv, but not in non-tuberculous mycobacteria-derived culture filtrate proteins. In addition, sMTL-13 leads to an increased IFN-gamma production by PBMC from active tuberculosis (ATB) patients. Furthermore, sera from ATB patients displayed high titers of IgG Ab against sMTL-13, a response found to be decreased following successful anti-tuberculosis therapy. Together, our findings reveal a secreted 13 kDa ricin-like lectin from Mtb, which is immunologically recognized during ATB and could serve as a biomarker of disease treatment.
Publisher: Elsevier BV
Date: 04-2020
Publisher: Frontiers Media SA
Date: 14-02-2023
DOI: 10.3389/FMOLB.2023.1069764
Abstract: Introduction: Spider venoms are a unique source of bioactive peptides, many of which display remarkable biological stability and neuroactivity. Phoneutria nigriventer , often referred to as the Brazilian wandering spider, banana spider or “armed” spider, is endemic to South America and amongst the most dangerous venomous spiders in the world. There are 4,000 envenomation accidents with P. nigriventer each year in Brazil, which can lead to symptoms including priapism, hypertension, blurred vision, sweating, and vomiting. In addition to its clinical relevance, P. nigriventer venom contains peptides that provide therapeutic effects in a range of disease models. Methods: In this study, we explored the neuroactivity and molecular ersity of P. nigriventer venom using fractionation-guided high-throughput cellular assays coupled to proteomics and multi-pharmacology activity to broaden the knowledge about this venom and its therapeutic potential and provide a proof-of-concept for an investigative pipeline to study spider-venom derived neuroactive peptides. We coupled proteomics with ion channel assays using a neuroblastoma cell line to identify venom compounds that modulate the activity of voltage-gated sodium and calcium channels, as well as the nicotinic acetylcholine receptor. Results: Our data revealed that P. nigriventer venom is highly complex compared to other neurotoxin-rich venoms and contains potent modulators of voltage-gated ion channels which were classified into four families of neuroactive peptides based on their activity and structures. In addition to the reported P. nigriventer neuroactive peptides, we identified at least 27 novel cysteine-rich venom peptides for which their activity and molecular target remains to be determined. Discussion: Our findings provide a platform for studying the bioactivity of known and novel neuroactive components in the venom of P. nigriventer and other spiders and suggest that our discovery pipeline can be used to identify ion channel-targeting venom peptides with potential as pharmacological tools and to drug leads.
Publisher: MDPI AG
Date: 28-10-2022
Abstract: Australian funnel-web spiders are amongst the most dangerous venomous animals. Their venoms induce potentially deadly symptoms, including hyper- and hypotension, tachycardia, bradycardia and pulmonary oedema. Human envenomation is more frequent with the ground-dwelling species, including the infamous Sydney funnel-web spider (Atrax robustus) although, only two tree-dwelling species induce more severe envenomation. To unravel the mechanisms that lead to this stark difference in clinical outcomes, we investigated the venom transcriptome and proteome of arboreal Hadronyche cerberea and H. formidabilis. Overall, Hadronyche venoms comprised 44 toxin superfamilies, with 12 being exclusive to tree-dwellers. Surprisingly, the major venom components were neprilysins and uncharacterized peptides, in addition to the well-known ω- and δ-hexatoxins and double-knot peptides. The insecticidal effects of Hadronyche venom on sheep blowflies were more potent than Atrax venom, and the venom of both tree- and ground-dwelling species potently modulated human voltage-gated sodium channels, particularly NaV1.2. Only the venom of tree-dwellers exhibited potent modulation of voltage-gated calcium channels. H. formidabilis appeared to be under less ersifying selection pressure compared to the newly adapted tree-dweller, H. cerberea. Thus, this study contributes to unravelling the fascinating molecular and pharmacological basis for the severe envenomation caused by the Australian tree-dwelling funnel-web spiders.
Publisher: Elsevier BV
Date: 07-2018
DOI: 10.1016/J.BMC.2018.03.031
Abstract: Both N- and T-type calcium ion channels have been implicated in pain transmission and the N-type channel is a well-validated target for the treatment of neuropathic pain. An SAR investigation of a series of substituted aminobenzothiazoles identified a subset of five compounds with comparable activity to the positive control Z160 in a FLIPR-based intracellular calcium response assay measuring potency at both Ca
Publisher: Wiley
Date: 17-06-2014
DOI: 10.1111/PIM.12118
Abstract: Schistosoma mansoni is a blood fluke parasite responsible for schistosomiasis. The best long-term strategy to control schistosomiasis is through immunization combined with drug treatment. In this study, we cloned, expressed and purified SmTSP-2 fused to the N- and C-terminal halves of Sm29 and tested these chimeras as vaccine candidates using an adjuvant approved to be used in humans. The results demonstrated that vaccination with SmTSP-2 fused to N- or C-terminus of Sm29-induced reduction in worm burden and liver pathology when compared to control animals. Additionally, we detected high levels of mouse-specific IgG, IgG1 and IgG2a against both chimeras and significant amounts of IFN-γ and TNF-α and no IL-4. Finally, studies with sera from patients resistant to infection and living in schistosomiasis endemic areas revealed high levels of specific IgG to both chimeras when compared to healthy in iduals. In conclusion, SmTSP-2/Sm29 chimeras tested here induced partial protection against infection and might be a potential vaccine candidate.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1MD00331C
Abstract: Experimental and theoretical evidence that the blockade of Ca V 2.2 ion channels by TCAs is partially responsible for their analgesic effects.
Publisher: Frontiers Media SA
Date: 11-04-2019
Publisher: Elsevier BV
Date: 06-2009
DOI: 10.1016/J.VACCINE.2009.04.068
Abstract: Schistosomiasis continues to be a significant public health problem that affects 200 million people worldwide. This is one of the most important parasitic diseases, and one whose effective control is unlikely in the absence of a vaccine. In this study, we have isolated a cDNA clone encoding the Schistosoma mansoni Sm21.6 protein that has 45% and 44% identity with Sm22.6 and Sj21.7 EF-hand containing antigens, respectively. Confocal microscopy analysis revealed that Sm21.6 is a membrane-associated protein localized on the S. mansoni adult worm. Mouse immunization with rSm21.6 induced a mixed Th1/Th2 cytokine profile and no protection against infection. However, vaccination with rSm21.6 reduced by 28% of liver granuloma numbers, 21% of granuloma area and 34% of fibrosis. Finally, rSm21.6 was recognized by sera from in iduals resistant to reinfection compared with patients susceptible to reinfection and this molecule should be further studied as potential biomarker for disease resistance. In conclusion, Sm21.6 is a new tegument protein from S. mansoni that plays an important role in reducing pathology induced by parasite infection.
Publisher: Bentham Science Publishers Ltd.
Date: 2009
Publisher: Cold Spring Harbor Laboratory
Date: 29-10-2023
Publisher: Cold Spring Harbor Laboratory
Date: 18-11-2022
DOI: 10.1101/2022.11.17.516848
Abstract: Spider venoms are a unique source of bioactive peptides, many of which display remarkable biological stability and neuroactivity. Phoneutria nigriventer , often referred to as the Brazilian wandering spider, banana spider or “armed” spider, is endemic to South America and amongst the most dangerous venomous spiders in the world. There are 4,000 envenomation accidents with P. nigriventer each year in Brazil, which can lead to symptoms including priapism, hypertension, blurred vision, sweating, and vomiting. In addition to its clinical relevance, P. nigriventer venom contains peptides that provide therapeutic effects in a range of disease models. In this study, we explored the neuroactivity and molecular ersity P. nigriventer venom using fractionation-guided high-throughput cellular assays coupled to proteomics and multi-pharmacology activity to broaden the knowledge about this venom and its therapeutic potential and provide a proof-of-concept for an investigative pipeline to study spider-venom derived neuroactive peptides. We coupled proteomics with ion channel assays using a neuroblastoma cell line to identify venom compounds that modulate the activity of voltage-gated sodium and calcium channels, as well as the nicotinic acetylcholine receptor. Our data revealed that P. nigriventer venom is highly complex compared to other neurotoxin-rich venoms and contains potent modulators of voltage-gated ion channels which were classified into four families of neuroactive peptides based on their activity and structures. In addition to the reported P. nigriventer neuroactive peptides, we identified at least 27 novel cysteine-rich venom peptides for which their activity and molecular target remains to be determined. Our findings provide a platform for studying the bioactivity of known and novel neuroactive components in the venom of P. nigriventer and other spiders and suggests that our discovery pipeline can be used to identify ion channel-targeting venom peptides with potential as pharmacological tools and to drug leads.
Publisher: Wiley
Date: 2016
DOI: 10.1111/MEC.13504
Abstract: Venoms comprise of complex mixtures of peptides evolved for predation and defensive purposes. Remarkably, some carnivorous cone snails can inject two distinct venoms in response to predatory or defensive stimuli, providing a unique opportunity to study separately how different ecological pressures contribute to toxin ersification. Here, we report the extraordinary defensive strategy of the Rhizoconus subgenus of cone snails. The defensive venom from this worm-hunting subgenus is unusually simple, almost exclusively composed of αD-conotoxins instead of the ubiquitous αA-conotoxins found in the more complex defensive venom of mollusc- and fish-hunting cone snails. A similarly compartmentalized venom gland as those observed in the other dietary groups facilitates the deployment of this defensive venom. Transcriptomic analysis of a Conus vexillum venom gland revealed the αD-conotoxins as the major transcripts, with lower amounts of 15 known and four new conotoxin superfamilies also detected with likely roles in prey capture. Our phylogenetic and molecular evolution analysis of the αD-conotoxins from five subgenera of cone snails suggests they evolved episodically as part of a defensive strategy in the Rhizoconus subgenus. Thus, our results demonstrate an important role for defence in the evolution of conotoxins.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 17-08-2021
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2018
Publisher: Public Library of Science (PLoS)
Date: 16-03-2017
Publisher: Wiley
Date: 07-07-2016
DOI: 10.1038/ICB.2015.61
Abstract: The schistosome blood flukes are some of the largest global causes of parasitic morbidity. Further study of the specific antibody response during schistosomiasis may yield the vaccines and diagnostics needed to combat this disease. Therefore, for the purposes of antigen discovery, sera and antibody-secreting cell (ASC) probes from semi-permissive rats and sera from susceptible mice were used to screen a schistosome protein microarray. Following Schistosoma japonicum infection, rats had reduced pathology, increased antibody responses and broader antigen recognition profiles compared with mice. With successive infections, rat global serological reactivity and the number of recognized antigens increased. The local antibody response in rat skin and lung, measured with ASC probes, increased after parasite migration and contributed antigen-specific antibodies to the multivalent serological response. In addition, the temporal variation of anti-parasite serum antibodies after infection and reinfection followed patterns that appear related to the antigen driving the response. Among the 29 antigens differentially recognized by the infected hosts were numerous known vaccine candidates, drug targets and several S. japonicum homologs of human schistosomiasis resistance markers-the tegument allergen-like proteins. From this set, we prioritized eight proteins that may prove to be novel schistosome vaccine and diagnostic antigens.
Publisher: Elsevier BV
Date: 06-2003
DOI: 10.1016/S0041-0101(03)00011-4
Abstract: The aim of the present study was the molecular cloning of toxins active on calcium channels expressed by the spider Phoneutria nigriventer. Clones encoding the toxins Pn3-3A, Pn3-4A, Tx3-5, Pn3-5A, Tx3-6, Pn3-6A and Pn3-6B were identified from a cDNA library derived from the venom gland of this spider, revealing toxins of 49, 76, 45, 39, 55 and 58 amino acids residues, respectively, with polypeptide precursors being composed of three major portions: a signal peptide, a propeptide and finally, the mature toxin. A high degree of homology with the amino acid sequence was found between Pn3-3A and the neurotoxin Tx3-3 (identity of 79%), and between Pn3-4A and the neurotoxin Tx3-4 (identity of 95%). The deduced amino acid sequence for the mature polypeptides Tx3-5 and Tx3-6 confirms the polypeptide sequence previously published for these neurotoxins. In addition, the toxin Pn3-5A showed 58% identity to the Tx3-5 amino acid sequence, and the toxins Pn3-6A and Pn3-6B showed 85 and 33% identity, respectively, to the Tx3-6 amino acid sequence.
Publisher: Proceedings of the National Academy of Sciences
Date: 10-07-2023
Abstract: Larvae of the genus Megalopyge (Lepidoptera: Zygaenoidea: Megalopygidae), known as asp or puss caterpillars, produce defensive venoms that cause severe pain. Here, we present the anatomy, chemistry, and mode of action of the venom systems of caterpillars of two megalopygid species, the Southern flannel moth Megalopyge opercularis and the black-waved flannel moth Megalopyge crispata . We show that megalopygid venom is produced in secretory cells that lie beneath the cuticle and are connected to the venom spines by canals. Megalopygid venoms consist of large aerolysin-like pore-forming toxins, which we have named megalysins, and a small number of peptides. The venom system differs markedly from those of previously studied venomous zygaenoids of the family Limacodidae, suggestive of an independent origin. Megalopygid venom potently activates mammalian sensory neurons via membrane permeabilization and induces sustained spontaneous pain behavior and paw swelling in mice. These bioactivities are ablated by treatment with heat, organic solvents, or proteases, indicating that they are mediated by larger proteins such as the megalysins. We show that the megalysins were recruited as venom toxins in the Megalopygidae following horizontal transfer of genes from bacteria to the ancestors of ditrysian Lepidoptera. Megalopygids have recruited aerolysin-like proteins as venom toxins convergently with centipedes, cnidarians, and fish. This study highlights the role of horizontal gene transfer in venom evolution.
Publisher: Elsevier BV
Date: 09-2020
Publisher: MDPI AG
Date: 14-03-2019
DOI: 10.3390/MD17030165
Abstract: Integrated venomics techniques have shown that variable processing of conotoxins from Conus marmoreus resulted in a dramatic expansion in the number of expressed conotoxins. One conotoxin from C. marmoreus, the χ-conotoxin MrIA, is a selective inhibitor of human norepinephrine transporters (hNET) and therefore a drug candidate for attenuating chronic neuropathic pain. It has been found that “messy” processing of the MrIA transcripts results in the expression of MrIA analogs with different truncations of the pro-peptide that contains portions of the MrIA molecule. The aim of this study was to investigate if variable processing of the expressed peptides results in modulation of the existing hNET pharmacology or creates new pharmacologies. To this end, a number of MrIA analogs found in C. marmoreus venom were synthesized and evaluated for their activity at hNET receptors. While several of the analogs exhibited norepinephrine transporter inhibitory activity comparable to that of MrIA, none significantly improved on the potency of conotoxin MrIA, and those analogs with disrupted pharmacophores produced greatly reduced NET inhibition, confirming previous structure-activity relationships seen on χ-class conopeptides. Additionally, analogs were screened for new activities on ion channels using calcium influx assays, although no major new pharmacology was revealed.
Publisher: Complexo de Ensino Superior Meridional S.A.
Date: 12-2017
DOI: 10.18256/2447-3944.2017.V3I2.2019
Abstract: A metodologia de aprendizagem ativa denominada Aprendizado Baseado em Problemas (PBL) é largamente utilizada em cursos de Medicina, Odontologia e Enfermagem em todos os continentes. Porém, existem dois modelos básicos de PBL: o puro, em que o ensino é baseado apenas em solução de problemas e o misto, que apresenta a união das vantagens do ensino tradicional e do PBL puro. Como alternativa ao ensino tradicional das ciências básicas, caracterizado como descontextualizado da realidade clínica e cirúrgica na Medicina Veterinária, o objetivo do trabalho foi demonstrar que o PBL no modelo misto pode ser utilizado para o ensino integrado dos temas da Biologia Celular e da Clínica Médica Veterinária. Assim, sugeriu-se um plano de trabalho docente baseado em problemas inspirados na realidade da Clinica Médica de Equinos, nos quais os conhecimentos da Biologia Celular são necessários para a resolução e fechamento do diagnóstico.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2011
DOI: 10.1109/TCBB.2011.78
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7NJ04969B
Abstract: Novel mixed opioid agonist/N-VGCC blocker peptides, design, synthesis and biological profile.
Location: Australia
No related grants have been discovered for Fernanda Cardoso.