The journal of venomous animals and toxins including tropical diseases最新文献

{"title":"Effects of venoms on neutrophil respiratory burst: a major inflammatory function.","authors":"Jamel El-Benna,&nbsp;Margarita Hurtado-Nedelec,&nbsp;Marie-Anne Gougerot-Pocidalo,&nbsp;Pham My-Chan Dang","doi":"10.1590/1678-9199-JVATITD-2020-0179","DOIUrl":"https://doi.org/10.1590/1678-9199-JVATITD-2020-0179","url":null,"abstract":"<p><p>Neutrophils play a pivotal role in innate immunity and in the inflammatory response. Neutrophils are very motile cells that are rapidly recruited to the inflammatory site as the body first line of defense. Their bactericidal activity is due to the release into the phagocytic vacuole, called phagosome, of several toxic molecules directed against microbes. Neutrophil stimulation induces release of this arsenal into the phagosome and induces the assembly at the membrane of subunits of the NAPDH oxidase, the enzyme responsible for the production of superoxide anion that gives rise to other reactive oxygen species (ROS), a process called respiratory burst. Altogether, they are responsible for the bactericidal activity of the neutrophils. Excessive activation of neutrophils can lead to extensive release of these toxic agents, inducing tissue injury and the inflammatory reaction. Envenomation, caused by different animal species (bees, wasps, scorpions, snakes etc.), is well known to induce a local and acute inflammatory reaction, characterized by recruitment and activation of leukocytes and the release of several inflammatory mediators, including prostaglandins and cytokines. Venoms contain several molecules such as enzymes (phospholipase A2, L-amino acid oxidase and proteases, among others) and peptides (disintegrins, mastoporan, parabutoporin etc.). These molecules are able to stimulate or inhibit ROS production by neutrophils. The present review article gives a general overview of the main neutrophil functions focusing on ROS production and summarizes how venoms and venom molecules can affect this function.</p>","PeriodicalId":520810,"journal":{"name":"The journal of venomous animals and toxins including tropical diseases","volume":" ","pages":"e20200179"},"PeriodicalIF":2.4,"publicationDate":"2021-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8237995/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39174071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neuroactive venom compounds obtained from <i>Phlogiellus bundokalbo</i> as potential leads for neurodegenerative diseases: insights on their acetylcholinesterase and beta-secretase inhibitory activities <i>in vitro</i>.","authors":"Simon Miguel M Lopez,&nbsp;Jeremey S Aguilar,&nbsp;Jerene Bashia B Fernandez,&nbsp;Angelic Gayle J Lao,&nbsp;Mitzi Rain R Estrella,&nbsp;Mark Kevin P Devanadera,&nbsp;Cydee Marie V Ramones,&nbsp;Aaron Joseph L Villaraza,&nbsp;Leonardo A Guevarra,&nbsp;Myla R Santiago-Bautista,&nbsp;Librado A Santiago","doi":"10.1590/1678-9199-JVATITD-2021-0009","DOIUrl":"https://doi.org/10.1590/1678-9199-JVATITD-2021-0009","url":null,"abstract":"<p><strong>Background: </strong>Spider venom is a rich cocktail of neuroactive compounds designed to prey capture and defense against predators that act on neuronal membrane proteins, in particular, acetylcholinesterases (AChE) that regulate synaptic transmission through acetylcholine (ACh) hydrolysis - an excitatory neurotransmitter - and beta-secretases (BACE) that primarily cleave amyloid precursor proteins (APP), which are, in turn, relevant in the structural integrity of neurons. The present study provides preliminary evidence on the therapeutic potential of <i>Phlogiellus bundokalbo</i> venom against neurodegenerative diseases.</p><p><strong>Methods: </strong>Spider venom was extracted by electrostimulation and fractionated by reverse-phase high-performance liquid chromatography (RP-HPLC) and characterized by matrix-assisted laser desorption ionization-time flight mass spectrometry (MALDI-TOF-MS). Neuroactivity of the whole venom was observed by a neurobehavioral response from <i>Terebrio molitor</i> larvae <i>in vivo</i> and fractions were screened for their inhibitory activities against AChE and BACE <i>in vitro</i>.</p><p><strong>Results: </strong>The whole venom from <i>P. bundokalbo</i> demonstrated neuroactivity by inducing excitatory movements from <i>T. molitor</i> for 15 min. Sixteen fractions collected produced diverse mass fragments from MALDI-TOF-MS ranging from 900-4500 Da. Eleven of sixteen fractions demonstrated AChE inhibitory activities with 14.34% (± 2.60e-4) to 62.05% (± 6.40e-5) compared with donepezil which has 86.34% (± 3.90e-5) inhibition (p > 0.05), while none of the fractions were observed to exhibit BACE inhibition. Furthermore, three potent fractions against AChE, F1, F3, and F16 displayed competitive and uncompetitive inhibitions compared to donepezil as the positive control.</p><p><strong>Conclusion: </strong>The venom of <i>P. bundokalbo</i> contains compounds that demonstrate neuroactivity and anti-AChE activities <i>in vitro</i>, which could comprise possible therapeutic leads for the development of cholinergic compounds against neurological diseases.</p>","PeriodicalId":520810,"journal":{"name":"The journal of venomous animals and toxins including tropical diseases","volume":" ","pages":"e20210009"},"PeriodicalIF":2.4,"publicationDate":"2021-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8237997/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39174072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel proline-rich M-superfamily conotoxin that can simultaneously affect sodium, potassium and calcium currents.","authors":"Manyi Yang,&nbsp;Yubin Li,&nbsp;Longfei Liu,&nbsp;Maojun Zhou","doi":"10.1590/1678-9199-JVATITD-2020-0164","DOIUrl":"https://doi.org/10.1590/1678-9199-JVATITD-2020-0164","url":null,"abstract":"<p><strong>Background: </strong>Conotoxins have become a research hotspot in the neuropharmacology field for their high activity and specificity in targeting ion channels and neurotransmitter receptors. There have been reports of a conotoxin acting on two ion channels, but rare reports of a conotoxin acting on three ion channels.</p><p><strong>Methods: </strong>Vr3a, a proline-rich M-superfamily conotoxin from a worm-hunting <i>Conus varius</i>, was obtained by solid-phase synthesis and identified by mass spectrometry. The effects of synthesized Vr3a on sodium, potassium and calcium currents were tested on rat DRG cells by patch clamp experiments. The further effects of Vr3a on human Ca_v1.2 and Ca_v2.2 currents were tested on HEK293 cells.</p><p><strong>Results: </strong>About 10 μM Vr3a has no effects on the peak sodium currents, but can induce a ~10 mV shift in a polarizing direction in the current-voltage relationship. In addition, 10 μM Vr3a can increase 19.61 ± 5.12% of the peak potassium currents and do not induce a shift in the current-voltage relationship. An amount of 10 μM Vr3a can inhibit 31.26% ± 4.53% of the peak calcium currents and do not induce a shift in the current-voltage relationship. The IC₅₀ value of Vr3a on calcium channel currents in rat DRG neurons is 19.28 ± 4.32 μM. Moreover, 10 μM Vr3a can inhibit 15.32% ± 5.41% of the human Ca_v1.2 currents and 12.86% ± 4.93% of the human Ca_v2.2 currents.</p><p><strong>Conclusions: </strong>Vr3a can simultaneously affect sodium, potassium and calcium currents. This novel triple-target conotoxin Vr3a expands understanding of conotoxin functions.</p>","PeriodicalId":520810,"journal":{"name":"The journal of venomous animals and toxins including tropical diseases","volume":" ","pages":"e20200164"},"PeriodicalIF":2.4,"publicationDate":"2021-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8230863/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39162463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel neuroprotective peptides in the venom of the solitary scoliid wasp <i>Scolia decorata ventralis</i>.","authors":"Carlos Alberto-Silva,&nbsp;Fernanda Calheta Vieira Portaro,&nbsp;Roberto Tadashi Kodama,&nbsp;Halyne Queiroz Pantaleão,&nbsp;Marisa Rangel,&nbsp;Ken-Ichi Nihei,&nbsp;Katsuhiro Konno","doi":"10.1590/1678-9199-JVATITD-2020-0171","DOIUrl":"https://doi.org/10.1590/1678-9199-JVATITD-2020-0171","url":null,"abstract":"<p><strong>Background: </strong>Solitary wasp venoms may be a rich source of neuroactive substances, since their venoms are used for paralyzing preys. We have been exploring bioactive constituents of solitary wasp venoms and, in this study, the component profile of the venom from a solitary scoliid wasp, <i>Scolia decorata ventralis</i>, was investigated through a comprehensive analysis using LC-MS. Two peptides were synthesized, and their neuroprotective properties were evaluated.</p><p><strong>Methods: </strong>A reverse-phase HPLC connected to ESI-MS was used for LC-MS analyses. Online mass fingerprinting was performed from TIC, and data-dependent tandem mass spectrometry gave the MS/MS spectra. The sequences of two major peptide components were determined by MALDI-TOF/TOF MS analysis, confirmed by solid phase synthesis. Using the synthetic peptides, biological activities were assessed. Cell integrity tests and neuroprotection analyzes using H₂O₂ as an oxidative stress inducer were performed for both peptides.</p><p><strong>Results: </strong>Online mass fingerprinting revealed that the venom contains 123 components, and the MS/MS analysis resulted in 33 full sequences of peptide components. The two main peptides, α-scoliidine (DYVTVKGFSPLR) and β-scoliidine (DYVTVKGFSPLRKA), present homology with the bradykinin C-terminal. Despite this, both peptides did not behave as substrates or inhibitors of ACE, indicating that they do not interact with this metallopeptidase. In further studies, β-scoliidine, but not α -scoliidine, showed protective effects against oxidative stress-induced neurotoxicity in PC12 cells through integrity and metabolism cell assays. Interestingly, β-scoliidine has the extension of the KA dipeptide at the C-terminal in comparison with α-scoliidine.</p><p><strong>Conclusion: </strong>Comprehensive LC-MS and MS/MS analyses from the <i>Scolia decorata ventralis</i> venom displayed the component profile of this venom. β-scoliidine showed an effective cytoprotective effect, probably due to the observed increase in the number of cells. This is the first report of solitary wasp venom peptides showing neuroprotective activity.</p>","PeriodicalId":520810,"journal":{"name":"The journal of venomous animals and toxins including tropical diseases","volume":" ","pages":"e20200171"},"PeriodicalIF":2.4,"publicationDate":"2021-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8215932/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39045244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Glycosylation of β1 subunit plays a pivotal role in the toxin sensitivity and activation of BK channels.","authors":"Xiaoli Wang,&nbsp;Qian Xiao,&nbsp;Yudan Zhu,&nbsp;Hong Qi,&nbsp;Dongxiao Qu,&nbsp;Yu Yao,&nbsp;Yuxiang Jia,&nbsp;Jingkan Guo,&nbsp;Jiwei Cheng,&nbsp;Yonghua Ji,&nbsp;Guoyi Li,&nbsp;Jie Tao","doi":"10.1590/1678-9199-JVATITD-2020-0182","DOIUrl":"https://doi.org/10.1590/1678-9199-JVATITD-2020-0182","url":null,"abstract":"<p><strong>Background: </strong>The accessory β1 subunits, regulating the pharmacological and biophysical properties of BK channels, always undergo post-translational modifications, especially glycosylation. To date, it remains elusive whether the glycosylation contributes to the regulation of BK channels by β1 subunits.</p><p><strong>Methods: </strong>Herein, we combined the electrophysiological approach with molecular mutations and biochemical manipulation to investigate the function roles of N-glycosylation in β1 subunits.</p><p><strong>Results: </strong>The results show that deglycosylation of β1 subunits through double-site mutations (β1 N80A/N142A or β1 N80Q/N142Q) could significantly increase the inhibitory potency of iberiotoxin, a specific BK channel blocker. The deglycosylated channels also have a different sensitivity to martentoxin, another BK channel modulator with some remarkable effects as reported before. On the contrary to enhancing effects of martentoxin on glycosylated BK channels under the presence of cytoplasmic Ca²⁺, deglycosylated channels were not affected by the toxin. However, the deglycosylated channels were surprisingly inhibited by martentoxin under the absence of cytoplasmic Ca²⁺, while the glycosylated channels were not inhibited under this same condition. In addition, wild type BK (α+β1) channels treated with PNGase F also showed the same trend of pharmacological results to the mutants. Similar to this modulation of glycosylation on BK channel pharmacology, the deglycosylated forms of the channels were activated at a faster speed than the glycosylated ones. However, the V_1/2 and slope were not changed by the glycosylation.</p><p><strong>Conclusion: </strong>The present study reveals that glycosylation is an indispensable determinant of the modulation of β1-subunit on BK channel pharmacology and its activation. The loss of glycosylation of β1 subunits could lead to the dysfunction of BK channel, resulting in a pathological state.</p>","PeriodicalId":520810,"journal":{"name":"The journal of venomous animals and toxins including tropical diseases","volume":" ","pages":"e20200182"},"PeriodicalIF":2.4,"publicationDate":"2021-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8183112/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39249777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vector saliva controlled inflammatory response of the host may represent the Achilles heel during pathogen transmission.","authors":"Claudia Demarta-Gatsi,&nbsp;Salah Mécheri","doi":"10.1590/1678-9199-JVATITD-2020-0155","DOIUrl":"https://doi.org/10.1590/1678-9199-JVATITD-2020-0155","url":null,"abstract":"<p><p>Infection with vector-borne pathogens starts with the inoculation of these pathogens during blood feeding. In endemic regions, the population is regularly bitten by naive vectors, implicating a permanent stimulation of the immune system by the vector saliva itself (pre-immune context). Comparatively, the number of bites received by exposed individuals from non-infected vectors is much higher than the bites from infected ones. Therefore, vector saliva and the immunological response in the skin may play an important role, so far underestimated, in the establishment of anti-pathogen immunity in endemic areas. Hence, the parasite biology and the disease pathogenesis in \"saliva-primed\" and \"saliva-unprimed\" individuals must be different. This integrated view on how the pathogen evolves within the host together with vector salivary components, which are known to be endowed with a variety of pharmacological and immunological properties, must remain the focus of any investigational study dealing with vector-borne diseases. Considering this three-way partnership, the host skin (immune system), the pathogen, and the vector saliva, the approach that consists in the validation of vector saliva as a source of molecular entities with anti-disease vaccine potential has been recently a subject of active and fruitful investigation. As an example, the vaccination with maxadilan, a potent vasodilator peptide extracted from the saliva of the sand fly <i>Lutzomyia longipalpis</i>, was able to protect against infection with various leishmanial parasites. More interestingly, a universal mosquito saliva vaccine that may potentially protect against a range of mosquito-borne infections including malaria, dengue, Zika, chikungunya and yellow fever. In this review, we highlight the key role played by the immunobiology of vector saliva in shaping the outcome of vector-borne diseases and discuss the value of studying diseases in the light of intimate cross talk among the pathogen, the vector saliva, and the host immune mechanisms.</p>","PeriodicalId":520810,"journal":{"name":"The journal of venomous animals and toxins including tropical diseases","volume":" ","pages":"e20200155"},"PeriodicalIF":2.4,"publicationDate":"2021-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8128132/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39018844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantity - but not diversity - of secreted peptides and proteins increases with age in the tree frog <i>Pithecopus nordestinus</i>.","authors":"Douglas O Mariano,&nbsp;Juliana M Sciani,&nbsp;Marta M Antoniazzi,&nbsp;Carlos Jared,&nbsp;Katia Conceição,&nbsp;Daniel C Pimenta","doi":"10.1590/1678-9199-JVATITD-2020-0105","DOIUrl":"https://doi.org/10.1590/1678-9199-JVATITD-2020-0105","url":null,"abstract":"<p><strong>Background: </strong>Amphibians inhabit the terrestrial environment, a conquest achieved after several evolutionary steps, which were still insufficient to make them completely independent of the aquatic environment. These processes gave rise to many morphological and physiological changes, making their skin (and cutaneous secretion) rich in bioactive molecules. Among the tree frogs, the secretion is composed mainly of peptides; but alkaloids, proteins and steroids can also be found depending on the species. The most known class of biologically active molecules is the antimicrobial peptides (AMPs) that act against bacteria, fungi and protozoans. Although these molecules are well-studied among the hylids, AMPs ontogeny remains unknown. Therefore, we performed peptidomic and proteomic analyses of <i>Pithecopus nordestinus</i> (formerly <i>Phyllomedusa nordestina</i>) in order to evaluate the peptide content in post-metamorphosed juveniles and adult individuals.</p><p><strong>Methods: </strong>Cutaneous secretion of both life stages of individuals was obtained and analyzed by LC-MS/MS after reduction and alkylation of disulfide bonds or reduction, alkylation and hydrolysis by trypsin.</p><p><strong>Results: </strong>Differences in the TIC profile of juveniles and adults in both treatments were observed. Moreover, the proteomic data revealed known proteins and peptides, with slight differences in the composition, according to the life stage and the treatment. AMPs were identified, and bradykinin-potentiating peptides were observed in trypsin-treated samples, which suggests a protein source of such peptide (cryptide).</p><p><strong>Conclusion: </strong>In general, skin secretion contents were similar between juveniles and adults, varying in quantity, indicating that the different stages of life are reflected in the number of molecules and not on their diversity.</p>","PeriodicalId":520810,"journal":{"name":"The journal of venomous animals and toxins including tropical diseases","volume":" ","pages":"e20200105"},"PeriodicalIF":2.4,"publicationDate":"2021-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8020714/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38885395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Leptospirosis diagnosis among patients suspected of dengue fever in Brazil.","authors":"Felipe Fornazari,&nbsp;Virgínia Bodelão Richini-Pereira,&nbsp;Sâmea Fernandes Joaquim,&nbsp;Pedro Gabriel Nachtigall,&nbsp;Helio Langoni","doi":"10.1590/1678-9199-JVATITD-2020-0118","DOIUrl":"https://doi.org/10.1590/1678-9199-JVATITD-2020-0118","url":null,"abstract":"<p><strong>Background: </strong>The early symptoms of leptospirosis and dengue fever are difficult to distinguish and can cause diagnostic confusion. Due to the large dengue epidemics that has occurred in Brazil in recent years, it is possible that cases of leptospirosis were unreported. Therefore, we performed a retrospective study to detect leptospirosis in patients who were tested for dengue, but whose laboratory diagnoses were negative.</p><p><strong>Methods: </strong>Sera samples from 2,017 patients from 48 cities located in the central region of São Paulo state, Brazil, were studied. All samples were subjected to the microscopic agglutination test (MAT), 305 of which were taken from patients five days or less since the onset of symptoms, and were additionally subjected to real-time polymerase chain reaction (PCR).</p><p><strong>Results: </strong>The overall prevalence of leptospirosis cases was 21 (1.04%), with 20 through MAT (18 for Icterohaemorrhagiae and two for the Cynopteri serogroup) and one through PCR (amplicon sequencing compatible with <i>Leptospira interrogans</i>). According to previously established criteria, eight cases of leptospirosis were classified as \"confirmed\" and 13 as \"probable\". The Brazilian notification system for health surveillance had no records for 16 patients positive for leptospirosis and, thus, they were considered unreported cases. Statistical analyses revealed that the prevalence of leptospirosis was higher in men (1.56%) than in women (0.56%), and the mean age was higher in positive patients (43.7 years) than in negative ones (32.3 years).</p><p><strong>Conclusion: </strong>The results indicated that patients suspected of dengue fever had evidence of leptospirosis or <i>Leptospira</i> infection, and most of these cases were unreported in the Brazilian notification system. The high burden of dengue may contribute to the misdiagnosis of leptospirosis, and health professionals should increase their awareness of leptospirosis as an important differential diagnosis of patients with suspicion of dengue.</p>","PeriodicalId":520810,"journal":{"name":"The journal of venomous animals and toxins including tropical diseases","volume":" ","pages":"e20200118"},"PeriodicalIF":2.4,"publicationDate":"2021-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996315/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25555724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proteolytic activity of <i>Triatoma infestans</i> saliva associated with PAR-2 activation and vasodilation.","authors":"Karla A Oliveira,&nbsp;Ricardo J S Torquato,&nbsp;Daniela C G Garcia Lustosa,&nbsp;Tales Ribeiro,&nbsp;Bruno W L Nascimento,&nbsp;Lilian C G de Oliveira,&nbsp;Maria A Juliano,&nbsp;Thaysa Paschoalin,&nbsp;Virginia S Lemos,&nbsp;Ricardo N Araujo,&nbsp;Marcos H Pereira,&nbsp;Aparecida S Tanaka","doi":"10.1590/1678-9199-JVATITD-2020-0098","DOIUrl":"https://doi.org/10.1590/1678-9199-JVATITD-2020-0098","url":null,"abstract":"<p><strong>Background: </strong><i>Triatoma infestans</i> (Hemiptera: Reduviidae) is a hematophagous insect and the main vector of <i>Trypanosoma cruzi</i> (Kinetoplastida: Trypanosomatidae). In the present study, the authors investigated whether a serine protease activity from the saliva of <i>T. infestans</i> has a role in vasomotor modulation, and in the insect-blood feeding by cleaving and activating protease-activated receptors (PARs).</p><p><strong>Methods: </strong><i>T. infestans</i> saliva was chromatographed as previously reported for purification of triapsin, a serine protease. The cleavage activity of triapsin on PAR peptides was investigated based on FRET technology. Mass spectrometry was used to analyze the sites of PAR-2 peptide cleaved by triapsin. NO measurements were performed using the DAN assay (2,3-diaminonapthalene). The vasorelaxant activity of triapsin was measured in vessels with or without functional endothelium pre-contracted with phenylephrine (3 µM). Intravital microscopy was used to assess the effect of triapsin on mouse skin microcirculation.</p><p><strong>Results: </strong>Triapsin was able to induce hydrolysis of PAR peptides and showed a higher preference for cleavage of the PAR-2 peptide. Analysis by mass spectrometry confirmed a single cleavage site, which corresponds to the activation site of the PAR-2 receptor. Triapsin induced dose-dependent NO release in cultured human umbilical vein endothelial cells (HUVECs), reaching a maximum effect at 17.58 nM. Triapsin purified by gel-filtration chromatography (10^-16 to 10^-9 M) was applied cumulatively to mouse mesenteric artery rings and showed a potent endothelium-dependent vasodilator effect (EC₃₀ = 10^-12 M). Nitric oxide seems to be partially responsible for this vasodilator effect because L-NAME (L-NG-nitroarginine methyl ester 300 µM), a nitric oxide synthetase inhibitor, did not abrogate the vasodilation activated by triapsin. Anti-PAR-2 antibody completely inhibited vasodilation observed in the presence of triapsin activity. Triapsin activity also induced an increase in the mouse ear venular diameter.</p><p><strong>Conclusion: </strong>Data from this study suggest a plausible association between triapsin activity mediated PAR-2 activation and vasodilation caused by <i>T. infestans</i> saliva.</p>","PeriodicalId":520810,"journal":{"name":"The journal of venomous animals and toxins including tropical diseases","volume":" ","pages":"e20200098"},"PeriodicalIF":2.4,"publicationDate":"2021-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7939238/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25501037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Escherichia coli</i> vacuolating factor, involved in avian cellulitis, induces actin contraction and binds to cytoskeleton proteins in fibroblasts.","authors":"Annelize Zambon Barbosa Aragão,&nbsp;Natália Galdi Quel,&nbsp;Paulo Pinto Joazeiro,&nbsp;Tomomasa Yano","doi":"10.1590/1678-9199-JVATITD-2020-0106","DOIUrl":"https://doi.org/10.1590/1678-9199-JVATITD-2020-0106","url":null,"abstract":"<p><strong>Background: </strong>Avian pathogenic <i>Escherichia coli</i> (APEC) isolated from avian cellulitis lesions produces a toxin, named <i>Escherichia coli</i> vacuolating factor (ECVF), that causes cell vacuolization and induces inflammatory response in broiler chicken.</p><p><strong>Methods: </strong>We investigated the intracellular activities of ECVF in avian fibroblasts using fluorescence staining, electron microscopy, MTT and LDH measurements. As ECVF act specifically in avian cells, we performed blotting assay followed by mass spectrometry to better understand its initial intracellular protein recognition.</p><p><strong>Results: </strong>ECVF induced actin contraction, mitochondrial damage and membrane permeability alterations. Ultrastructural analysis showed intracellular alterations, as nuclear lobulation and the presence of degraded structures inside the vacuoles. Moreover, ECVF induced cell death in fibroblasts. ECVF-biotin associates to at least two proteins only in avian cell lysates: alpha-actinin 4 and vinculin, both involved in cytoskeleton structure.</p><p><strong>Conclusion: </strong>These findings demonstrated that ECVF plays an important role in avian cellulitis, markedly in initial steps of infection. Taken together, the results place this toxin as a target for drug and/or vaccine development, instead of the use of large amounts antibiotics.</p>","PeriodicalId":520810,"journal":{"name":"The journal of venomous animals and toxins including tropical diseases","volume":" ","pages":"e20200106"},"PeriodicalIF":2.4,"publicationDate":"2021-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7941731/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25501038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}