Journal of Venomous Animals and Toxins Including Tropical Diseases最新文献

Background: This study examines the impact of Phα1β, a spider peptide derived from the venom of Phoneutria nigriventer, on the Kv11.1 potassium channel in HEK293 cells transfected with the human ERG potassium channel. Phα1β inhibits high-voltage calcium channels and acts as an antagonist of the TRPA1 receptor, both of which play crucial roles in pain transduction pathways. Over the past 15 years, our research has demonstrated the potential of Phα1β, in both its native and recombinant forms, as a promising analgesic drug through preclinical tests conducted on rodent pain models. Regulatory agencies require the evaluation of new drugs on human ERG channels.

Methods: To assess hERG potassium channel inhibition, we utilized the FLIPR® Potassium Assay, a commercially available kit. The assay involved testing the effects of Phα1β alongside the well-established hERG potassium channel blocker dofetilide, which served as a positive control. The viability of HEK-293 cells was assessed using the colorimetric MTT reduction test (3-(4, dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), whereby viable cells reduce the MTT salt, forming a formazan complex within their mitochondria, as previously described.

Results: Phα1β was tested at concentrations of 56, 225, 450, and 900 pMol, resulting in a discreet inhibition of hERG potassium channel activity at higher concentrations, approximately 13.47%, with an IC₅₀ value exceeding 900 pMol. Dofetilide, administered at concentrations ranging from 0.0001 to 10 µM, displayed a concentration-dependent inhibition of the hERG potassium channel, with a mean IC₅₀ value of 0.1642 µM (0.1189-0.2282 µM). To evaluate cytotoxicity, HEK293-hERG cells were exposed to Phα1β concentrations of 56/900 pMol for 24 hours, resulting in no significant alteration in cell viability.

Conclusion: Our findings indicate that even at high concentrations, Phα1β does not impede the functionality of the hERG potassium channel nor affect cell viability.

Envenomation by aquatic species is an under-investigated source of human morbidity and mortality. Increasing population density along marine and freshwater coastlines increases these incidents. Specific occupational groups - including commercial fishery workers, fisherfolk, marine tourism workers, and researchers - rely on aquatic resources for their livelihood. While diverse venomous aquatic species exhibit a broad array of habitats worldwide, they are most abundant in the tropics. Specific tropical regions present historic "hot spot" areas of concern for occupational groups with heightened risk of aquatic envenomation. Towards the overall objective of characterizing the health burden of aquatic envenomations, this review seeks to define (1) vulnerable, high-risk populations and (2) geographic hot-spot regions. To formally assess these metrics, a systematic literature review was performed where inclusion criteria requirements were peer-reviewed, published, epidemiological studies with defined denominators from January 1, 2000, to July 31, 2024, on the topic of human envenomation by aquatic species. Fifty-three articles met the inclusion criteria. Excluded articles were comprised of case reports, news and magazine articles, and those in languages aside from English, French, Portuguese, and Spanish. Most of the included articles examined emergency department and poison-control datasets that reported few overall envenomations (< 1%) from populations with physical and financial access to medical care. In contrast, datasets surveying beachgoers or fisherfolk directly, and life-guard incident reports, demonstrated that aquatic envenomation is an important source of injury for these groups and settings (envenomation frequency mean: 71%, median: 80%). Reports on additional high-risk groups, including marine and aquatic biologists, military personnel etc., and in key high-risk geographic regions including Thailand, Indonesia, and other Indo-Pacific countries were missing from the reviewed literature. Socio-demographic data were also largely missing from the literature. This systematic review highlights critical gaps where further research is needed, especially in under-represented regions and vulnerable populations.

Background: Micrurus mipartitus is a coral snake of public health concern in Colombia. Its venom is mainly composed of three-finger toxins (3FTxs), Mipartoxin-1 being the most abundant protein partially responsible for its lethal effect. In this work, we present the production of Mipartoxin-1 in a recombinant form and evaluate its immunogenic potential. Methods: A genetic construct HisrMipartoxin-1 was cloned into the pET28a vector and heterologous expression was obtained in E. coli BL21 (DE3). The recombinant HisrMipartoxin-1 protein was extracted from inclusion bodies, refolded in vitro, and isolated by affinity and RP-HPLC chromatography. The lethal effect of HisrMipartoxin-1 was tested, and antibodies against HisrMipartoxin-1 were produced by immunization in rabbits. The antibody titers were monitored by an ELISA test. The neutralizing ability of the antibodies, against the lethal effect of native toxins and M. mipartitus venom, was also assessed. Results: HisrMipartoxin-1 was detected on SDS-PAGE, with a molecular mass of around 11 kDa. The retention time was 16.0 minutes. HisrMipartoxin-1 did not exhibit lethality in mice; however, antibodies against HisrMipartoxin-1 recognized the native toxin, the whole venom of M. mipartitus, and a 3FTx from another species within the Micrurus genus. Furthermore, antibodies against HisrMipartoxin-1 completely neutralized the lethal effect of native Mipartoxin-1 in mice but not M. mipartitus whole venom. Conclusion: These findings indicate that HisrMipartoxin-1 might be used as an immunogen to develop anticoral antivenoms or complement them. This work is the first report of the heterologous expression of 3FTx from M. mipartitus.

Background: Medications currently used to treat pain are frequently associated with serious adverse effects and rapid development of tolerance. Thus, there is a need to develop more effective, and safer medicines for the population. Blocking NMDA receptors (NMDAR) has shown to be a promising target for the development of new drugs. That statement is due to NMDAR activation and glutamate release in the spinal cord which affects chronic pain modulation. Therefore, the aim of this study was to evaluate the possible spinal antinociceptive activity of PnTx4(5-5) toxin. The peptide is purified from the venom of the spider P. nigriventer and its affinity for NMDAR and sodium channels Nav1.2-1.6 has already been established.

Methods: We compared its effect and safety with MK-801 (NMDAR antagonist) and evaluated its influence on glutamate and reactive oxygen species (ROS) levels in CSF. PnTx4(5-5) was administered intrathecally in the Formalin test and co-administered with NMDA in the Spontaneous pain test. After three minutes of observation, mice cerebrospinal fluid was collected to measure glutamate and ROS levels.

Results: The spider peptide inhibited nociception as post-treatment in the inflammatory phase of the Formalin test. Furthermore, it inhibited spontaneous nociception induced by NMDA, being more potent and effective than MK-801 in both models tested. A glutamate rise level in the CSF of mice was significantly reduced by the toxin, but ROS increase was not affected. The animals' motor skills were not affected by the tested doses of NMDAR inhibitors.

Conclusion: In conclusion, the results suggest PnTx4(5-5) may mediate its antinociceptive effect in the spinal cord not only by inhibiting postsynaptic receptors but probably also by acting on autoreceptors. This effect does not affect the motricity of mice at the highest dose tested, which suggests that it has therapeutic potential and safety for use as a painkiller.

Background: Sea anemones are well known to contain multiple peptide toxins. However, of more than 1100 species of sea anemones distributed worldwide, only a little over 50 have been studied for peptide toxins. Therefore, innumerable unique and novel peptide toxins remain to be discovered in unstudied sea anemones.

Methods: Isolation of peptide toxins in the sea anemone Heteractis aurora was attempted by gel filtration and reverse-phase high performance liquid chromatography, using the toxicity to crabs as an index. The amino acid sequences of the isolated four toxins (Hau I-IV) and their precursors were determined using a combination of protein sequencing and cDNA cloning.

Results: Hau I and IV were potently lethal to crabs, whereas Hau II and III were only paralytic. The precursor proteins of the four toxins were commonly composed of a signal peptide, a propart, and the remaining region including a mature peptide. Interestingly, four and two copies of the mature peptide were present in the precursor proteins of Hau II and III, respectively. Homology searches revealed that Hau I (30 amino acid residues) is a novel peptide toxin, although it has the same cysteine pattern CXXC-C-C as the boundless β-hairpin (BBH) family. Hau II (27 amino acid residues) and III (28 amino acid residues) were homologous with the BBH family, whereas Hau IV (49 amino acid residues) was a new member of the well-known type 1 sodium channel toxin family.

Conclusion: This study showed that a novel class of toxin (Hau I), two BBH family toxins (Hau II and III), and a type 1 sodium channel toxin (Hau IV) are present in the toxin of the sea anemone H. aurora.

Visceral leishmaniasis (VL) is a neglected disease that is typical of tropical and subtropical parts of the world and is caused by the trypanosomatid Leishmania donovani complex. This disease is a multifactorial condition that involves parasitic, environmental, and immunogenetic characteristics. Genetic changes in genes encoding cytokines may be associated with changes in their expression and, consequently, with the development of clinical resistance or susceptibility to the disease. This systematic review and meta-analysis aimed to assess whether single nucleotide polymorphisms (SNPs) in interleukin genes influence the clinical consequences of visceral leishmaniasis infection. To this end, we carried out a systematic review and meta-analysis with structured searches in the EMBASE, PubMed, Scopus, SciELO, and Web of Science databases without time restrictions. Two independent reviewers examined the studies, performed data extraction, and assessed quality by assigning scores. If there were any discrepancies, a third reviewer with more experience was consulted. After the screening process, 28 articles were included in the systematic review and 9 in the final analysis of the meta-analysis. Statistical analyses were carried out using various genetic models. The odds ratio (OR) and corresponding 95% confidence intervals (CIs) were calculated to estimate the associations. Overall, the main clinical outcomes were classified as not associated or associated when they presented susceptibility, resistance, risk, or protective factors for the development of the disease. Associations between IFN-γ +874T/A polymorphisms in the dominant model (OR 1.64, 95% CI 1.13-2.38, I² = 0%, p < 0.01) and heterozygous model (OR 1.72, 95% CI 1.15-2.57, I² = 0%, p < 0.01) and IL-18 -137G/C in the recessive model (OR 1.33, 95% CI 1.02-1.71, I² = 9%, p = 0.03) and VL were observed. For the IL-10 gene SNPs, there was no significant association. Our findings suggest that SNPs in the IFN-γ and IL-18 genes may be associated with the risk of developing VL.

Elephantiasis, also known as lymphatic filariasis (LF), is a debilitating condition characterized by the thickening of the skin and muscles, primarily affecting the limbs, genitalia, and female breasts. Lymphatic filariasis is a major global health concern, affecting approximately 120 million people worldwide and having a significant impact on people's quality of life, mobility, and socio-economic status. Although LF is endemic in many parts of the world, including Africa, it is a neglected issue in Southern Africa, with little information available. According to the World Health Organisation, approximately 882.5 million people in 44 countries worldwide are at risk of contracting LF, making it the second most common vector-borne disease after malaria. The primary goal of this review was to assess the prevalence of elephantiasis in the Southern African Development Community (SADC) region. Lymphatic filariasis is endemic in four of the sixteen SADC countries, three countries have administered MDA to the population that required it and they are now under post-intervention surveillance, while LF is no longer a public health problem in Malawi. Global efforts to eliminate LF have been hampered by the non-availability of MDA in some SADC countries such as Angola, Mozambique, Zambia, and Zimbabwe. Despite the implementation of mass drug administration programs, a review of the literature reveals gaps in knowledge about LF prevalence cases in SADC countries. Each country faces unique challenges and successes in combating LF due to varying levels of available data and healthcare infrastructure. Some SADC countries continue to bear the burden of LF-related diseases, necessitating ongoing disease prevention and elimination efforts. This review emphasizes the importance of ongoing research, data collection, and novel policies to combat the spread of elephantiasis disease in the SADC region and beyond.

Glioblastoma (GB) is the most common type of malignant tumor of the central nervous system, responsible for significant morbidity and with a 5-year overall relative survival of only 6.8%. Without advances in treatment in the last twenty years, the standard of care continues to be maximum safe resection, Temozolomide (TMZ), and radiotherapy. Many new trials are ongoing, and despite showing increased progression-free survival, these trials did not improve overall survival. They did not consider the adverse effects of these therapies. Therefore, an increasing number of bioprospecting studies have used snake venom molecules to search for new strategies to attack GB selectively without producing side effects. The present review aims to describe GB characteristics and current and new approaches for treatment considering their side effects. Besides, we focused on the antitumoral activity of snake venom proteins from the Viperidae family against GB, exploring the potential for drug design based on in vitro and in vivo studies. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. In January 2024, a systematic search was performed in the PubMed, EMBASE, and Web of Science databases from January 2000 to December 2023. Search terms were selected based on the population/exposure/outcome (PEO) framework and combined using Boolean operators ("AND", "OR"). The search strategy used these terms: glioblastoma, glioma, high-grade glioma, WHO IV glioma, brain cancer, snake venom, Viperidae, and bioprospection. We identified 10 in vivo and in vitro studies with whole and isolated proteins from Viperidae venom that could have antitumor activity against glioblastoma. Studies in bioprospecting exploring the advantage of snake venom proteins against GB deserve to be investigated due to their high specificity, small size, inherent bioactivity, and few side effects to cross the blood-brain barrier (BBB) to reach the tumor microenvironment.

Background: Pathophysiological mechanisms of rheumatoid arthritis arise because of a proinflammatory environment, generated by the interaction of autoreactive lymphocytes and proinflammatory mediators. Current strategies to mitigate the progression of the disease produce adverse effects, so there is a need for new therapeutic strategies and molecular targets to treat this disease. In this context, evidence suggests that scorpion venoms could modulate the immune response and some important cellular mechanisms of pharmacological interest. To evaluate the immunomodulatory effect of the venom of Tityus sp. (a possible new species close to Tityus metuendus) peripheral blood mononuclear cells of women diagnosed with RA were compared to cells of a control group.

Methods: A case-control study was conducted with a sample of 10 women with a confirmed diagnosis of RA and controls matched by sex and age. The cytotoxicity of the venom was evaluated to find sublethal concentrations of the venom, and subsequently, their immunomodulatory capacity in terms of percentage of proliferation, cell activation, and cytokines production.

Results: the venom of Tityus sp. produced a decrease in the percentage of proliferation in the CD3⁺, CD3⁺CD4⁺, and CD3⁺CD8⁺ cell subpopulations of RA patients and healthy controls, at concentrations of 252 and 126 µg/mL. However, the venom did not induce significant differences in the percentage of cell activation markers. The venom caused a decrease in IL-10 at a concentration of 252 µg/mL compared to untreated cells from patients and controls. The remaining cytokines did not show significant differences.

Conclusion: the venom of Tityus sp. is a potential source of molecules with immunomodulatory ability in CD4 and CD8 T lymphocytes. This result directs venom characterization studies to identify pharmacological targets with immunomodulatory capacity in T lymphocytes to enhance research in the treatment of autoimmune disorders such as RA.

The effect of peptide toxins on voltage-gated ion channels can be reliably assessed using electrophysiological assays, such as the patch-clamp technique. However, much of the toxinological research done in Central and South America aims at purifying and characterizing biochemical properties of the toxins of vegetal or animal origin, lacking electrophysiological approaches. This may happen due to technical and infrastructure limitations or because researchers are unfamiliar with the techniques and cellular models that can be used to gain information about the effect of a molecule on ion channels. Given the potential interest of many research groups in the highly biodiverse region of Central and South America, we reviewed the most relevant conceptual and methodological developments required to implement the evaluation of the effect of peptide toxins on mammalian voltage-gated ion channels using patch-clamp. For that, we searched MEDLINE/PubMed and SciELO databases with different combinations of these descriptors: "electrophysiology", "patch-clamp techniques", "Ca²⁺ channels", "K⁺ channels", "cnidarian venoms", "cone snail venoms", "scorpion venoms", "spider venoms", "snake venoms", "cardiac myocytes", "dorsal root ganglia", and summarized the literature as a scoping review. First, we present the basics and recent advances in mammalian voltage-gated ion channel's structure and function and update the most important animal sources of channel-modulating toxins (e.g. cnidarian and cone snails, scorpions, spiders, and snakes), highlighting the properties of toxins electrophysiologically characterized in Central and South America. Finally, we describe the local experience in implementing the patch-clamp technique using two models of excitable cells, as well as the participation in characterizing new modulators of ion channels derived from the venom of a local spider, a toxins' source less studied with electrophysiological techniques. Fostering the implementation of electrophysiological methods in more laboratories in the region will strengthen our capabilities in many fields, such as toxinology, toxicology, pharmacology, natural products, biophysics, biomedicine, and bioengineering.