Highlights of animal venom research on the geographical variations of toxin components, toxicities and envenomation therapy

Geographic variation in stonefish (Synanceia spp.) venom

Stonefish (Synanceia spp.) possess a medically significant venom and are widely distributed throughout the Indo-Pacific. Yet, little is known about how the ecology of these animals may influence their venom. The aim of this study was to explore the effect of species and geographic location on stonefish venom composition. We collected the venom of Synanceia horrida (Estuarine Stonefish) and Synanceia verrucosa (Reef Stonefish) from various locations across Australia (Cairns, Brisbane, Caloundra, and Onslow), and Southeast Asia (Kota Kinabalu, and Cebu) and analysed these samples using SDS-PAGE, FPLC, and HPLC. Stonefish have a complex venom comprised of numerous components. Stonefish venom exhibited both similarities and variations in composition within species between geographically isolated populations, as well as between species in a single location. We speculate that the observed geographic and interspecific trends may be driven by similarities and differences in the selective pressures faced by these animals, particularly those associated with predator dynamics. The findings of this study have furthered our understanding of the ecology of stonefish and their toxins.

Clinicopathological biomarker patterns, venom detection and venom proteomics in canine Vipera berus envenomation

Vipera berus (V. berus) bites are associated with high morbidity, including kidney injury, in dogs. Although antivenom is often used and perceived effective to treat this type of snakebite, it is costly and associated with adverse events and specific diagnostics for this type of snakebite are lacking. We sought to improve diagnostics in V. berus envenomation by using currently available tools, including evaluating urinary albumin as a biomarker for snakebite-associated kidney injury. Additionally, we planned to adapt a method from human medicine for venom detection in clinical samples from bitten dogs and describe the composition of Norwegian V. berus venom. Serum biochemical analytes and urine albumin (ELISA) were measured in samples collected at 24 hours and two weeks after bite in 29 envenomated dogs. An adapted ELISA was applied to detect venom in urine and plasma collected from 25 cases between presentation and 24 hours after bite, using a commercial antivenom as the capture and detection antibody. Proteomic analysis of venom collected from 11 V. berus was performed using liquid chromatography-tandem mass spectrometry. Elevated serum C-reactive protein, creatine kinase, and aspartate aminotransferase were common for the case group. Although no case dogs showed acute kidney injury with azotemia and/or reduced urine output, elevated urinary albumin concentrations may indicate early or mild kidney injury in some case dogs. The venom ELISA detected positive signals in both plasma and urine for up to 24 hours after bite. However, with false positives detected in plasma, urine seemed to be the most appropriate body fluid for this assay. The venom proteome identified L-amino acid oxidases as the dominant component. In conclusion, serum biochemical and urinary albumin analyses are useful tools for evaluating canine V. berus envenomation. The venom ELISA is proposed as a promising tool for studies of V. berus envenomation and future diagnostic test development. Venom from the studied Norwegian V. berus was shown to differ considerably from previous reports from other countries, implying geographical variation in composition.

Comparative Analysis of Tentacle Extract and Nematocyst Venom: Toxicity, Mechanism, and Potential Intervention in the Giant Jellyfish Nemopilema nomurai

The giant jellyfish Nemopilema nomurai sting can cause local and systemic reactions; however, comparative analysis of the tentacle extract (TE) and nematocyst venom extract (NV), and its toxicity, mechanism, and potential intervention are still limited. This study compared venom from TE and NV for their composition, toxicity, and efficacy in vitro and in vivo used RAW264.7 cells and ICR mice. A total of 239 and 225 toxin proteins were identified in TE and NV by proteomics, respectively. Pathological analysis revealed that TE and NV caused heart and liver damage through apoptosis, necrosis, and inflammation, while TE exhibited higher toxicity ex vivo and in vivo. Biochemical markers indicated TE and NV elevated creatine kinase, lactatedehydrogenase, and aspartate aminotransferase, with the TE group showing a more significant increase. Transcriptomics and Western blotting indicated both venoms increased cytokines expression and MAPK signaling pathways. Additionally, 1 mg/kg PACOCF3 (the phospholipase A2 inhibitor) improved survival from 16.7% to 75% in mice. Our results indicate that different extraction methods impact venom activities, tentacle autolysis preserves toxin proteins and their toxicity, and PACOCF3 is a potential antidote, which establishes a good extraction method of jellyfish venom, expands our understanding of jellyfish toxicity, mechanism, and provides a promising intervention.

Transcriptomic analyses reveals a diverse venom composition in Agelena limbata (Araneae: Agelenaidae)

Spider venom is a natural source of diverse biomolecules, but due to technical limitations, only a small fraction has been studied. With the advancement of omics technologies, research on spider venom has broadened, greatly promoting systematic studies of spider venom. Agelena limbata is a common spider found in vegetation, known for constructing funnel-shaped webs, and feeding on insects such as Diptera and Homoptera. However, due to its small size and the difficulty in obtaining venom, the composition of Agelena limbata venom has never been studied. In this study, a transcriptomics approach was used to analyze the toxin components in the venom of Agelena limbata, resulting in the identification of 28 novel toxin-like sequences and 24 peptidases. Based on sequence similarity and differences in cysteine motifs, the 28-novel toxin-like sequences were classified into 10 superfamilies. According to the results annotated in the database, the 24 peptidases were divided into six distinct families, with the serine protease family being the most common. A phylogenetic tree was constructed using the toxin-like sequences of Agelena limbata along with Psechrus triangulus and Hippasa lycosina. An analysis of the structural domains and motifs of Agelena limbata was also conducted. The results indicated that Agelena limbata is more distantly related to the other two species of funnel-web spiders, and that the toxin superfamily IX has a unique function compared to the other superfamilies. This study reveals the components of the Agelena limbata venom, deepening our understanding of it, and through bioinformatics analysis, has identified unique functions of the toxin superfamilies, providing a scientific basis for the development of bioactive drugs in the future.

Exosomes as mediators of signal transmitters in biotoxins toxicity: a comprehensive review

Small membranes known as exosomes surround them and are released by several cell types both in vitro and in vivo. These membranes are packed with a variety of biomolecules, including proteins, lipids, deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and non-coding RNA (ncRNA). As a source of biological nanomaterials, exosomes play a role in information and substance transmission between cells and have been identified as a general method of facilitating communication during interactions between the body, target organs, and toxins.. In order to understand the changes and mechanism of the composition and level of exosomes after biotoxin infection, this review focuses on current findings on the exosomes and highlights their novel uses in the toxicity mechanism. Exosomes are mainly used as a delivery carrier or mediated by receptors, and play an immune role after the toxin enters the body. This review expounds on the importance of exosomes in the toxicological mechanism of biotoxins and provides new insights for further diagnosis of toxic biomarkers, detoxification, and treatment development.

Exploring the Efficacy of Hydroxybenzoic Acid Derivatives in Mitigating Jellyfish Toxin-Induced Skin Damage: Insights into Protective and Reparative Mechanisms

The escalation of jellyfish stings has drawn attention to severe skin reactions, underscoring the necessity for novel treatments. This investigation assesses the potential of hydroxybenzoic acid derivatives, specifically protocatechuic acid (PCA) and gentisic acid (DHB), for alleviating Nemopilema nomurai Nematocyst Venom (NnNV)-induced injuries. By employing an in vivo mouse model, the study delves into the therapeutic efficacy of these compounds. Through a combination of ELISA and Western blot analyses, histological examinations, and molecular assays, the study scrutinizes the inflammatory response, assesses skin damage and repair mechanisms, and investigates the compounds' ability to counteract venom effects. Our findings indicate that PCA and DHB significantly mitigate inflammation by modulating critical cytokines and pathways, altering collagen ratios through topical application, and enhancing VEGF and bFGF levels. Furthermore, both compounds demonstrate potential in neutralizing NnNV toxicity by inhibiting metalloproteinases and phospholipase-A2, showcasing the viability of small-molecule compounds in managing toxin-induced injuries.

Molecular diversity assessed by MALDI mass spectrometry of two scorpion species venom from two different locations in Morocco

Scorpion venom is a cocktail of molecules whose composition is remarkably plastic, controlled by several factors. The Moroccan scorpion fauna is characterized by its richness and high rate of endemism and the venom molecular variability of many species is not yet well characterized. The aim of the present study was to highlight the molecular variability of the venom composition of Androctonus amoreuxi and Buthacus stockmanni (endemic species), both belonging to the Buthidae family, collected from two Moroccan regions, Zagora and Tan-tan. Characterization of the molecular mass fingerprints (MFPs) of each specimen was performed by Matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) using a sandwich (Sand) and a dried-droplet (DD) sample preparation and dilutions. Considering these two methods, a total of 828 ion signals were detected, and Sand method produced more adducts (56%) than DD (44%). We observed interspecific variations in the venom composition between these two species showing they share 235 ion signals, while 226 and 367 are specific for these two species, respectively. Moreover, B. stockmanni specimens showed a clear difference in their MFPs between the two geographical areas studied, suggesting intraspecific variations. Moreover, specimens from each population also show an intraspecific variability. In addition, for the same individual, a variation in the venom composition was also recorded depending on the milking frequency. Our results confirmed the presence of characteristic components in each extracted venom sample. In conclusion, MFPs assessed by MALDI-MS represent a fast, non-supervised, sensitive, reliable and cost-efficient approach for taxonomic identification and molecular variability characterization. This study undoubtedly represents a step forward for understanding the scorpion venom plasticity, intra/inter variations, and their temporal and geographical variability.

In-depth immunorecognition and neutralization analyses of Micrurus mipartitus and M. dumerilii venoms and toxins by a commercial antivenom

In Colombia, the Micrurus genus comprises 30 species, including M. mipartitus and M. dumerilii, which are of major clinical relevance due to their wide geographical distribution and the number of snakebites inflicted by them. These neurotoxic envenomations are characterized by neuromuscular paralysis attributed to venom components such as three-finger toxins (3FTx) and phospholipases (PLA2). Additionally, there is limited information available on the neutralizing coverage of commercially available antivenoms, underscoring the need to perform studies to assess the cross-neutralizing ability of these life-saving products. Therefore, we present an in-depth immunorecognition analysis by the anticoral-INS antivenom from Colombia on the M. mipartitus and M. dumerilii venoms. The antivenom cross-recognized the whole venoms and their components with different intensities. For instance, the antivenom showed better recognition on PLA2s than on 3FTxs in both venoms. Moreover, at doses tested, the antivenom totally neutralized the lethal effect of M. dumerilii venom; however, it did not neutralize this effect induced by M. mipartitus venom and its main toxic components from the southwestern region of the department of Antioquia. Furthermore, the anticoral-INS antivenom displayed better cross-immunorecognition of PLA2-predominant Micrurus venoms than of 3FTx-predominant Micrurus venoms. This highlights the need to include venoms from both types of venom patterns in the immunization mixture to produce antivenoms against coral snakes. Finally, our results suggest the need for further research to optimize the composition of immunizing mixtures for antivenom production and improve their efficacy against coral snake envenomation in Colombia and the Americas.

Wasp venom-induced acute kidney injury: current progress and prospects

Wasp venom can trigger local and systemic reactions, with the kidneys being commonly affected, potentially causing acute kidney injury (AKI). Despite of the recent advances, our knowledge on the underlying mechanisms of toxicity and targeted therapies remain poor. AKI can result from direct nephrotoxic effects of the wasp venom or secondary rhabdomyolysis and intravascular hemolysis, which will release myoglobin and free hemoglobin. Inflammatory responses play a central role in these pathological mechanisms. Noteworthily, the successful establishment of a suitable experimental model can assist in basic research and clinical advancements related to wasp venom-induced AKI. The combination of therapeutic plasma exchange and continuous renal replacement therapy appears to be the preferred treatment for wasp venom-induced AKI. In addition, studies on cilastatin and varespladib for wasp venom-induced AKI treatment have shown their potential as therapeutic agents. This review summarizes the available evidence on the mechanisms and treatment of wasp venom-induced AKI, with a particular focus on the role of inflammatory responses and potential targets for therapeutic drugs, and, therefore, aiming to support the development of clinical treatment against wasp venom-induced AKI.

Bee Venom Causes Oxidative Stress, Biochemical and Histopathological Changes in the Kidney of Mice

Accidents with venomous bees are a serious worldwide health concern. Since the kidney has been reported as the main venom-target organ, the present study was undertaken to investigate the in vivo nephrotoxic effect of Algerian bee venom (ABV) (Apis mellifera intermissa) collected in the middle east of Algeria. A preliminary study was performed on ABV to identify the ABV using SDS-PAGE analysis and to determine the in vivo intraperitoneal median lethal dose (LD50) using the Probit analysis test. In vivo nephrotoxic effect was assessed through the determination of physiological and kidney biochemical markers in mice intraperitoneally injected with ABV at doses of 0.76 (D1); 1.14 (D2) and 2.29 mg/kg body weight (bwt) (D3), corresponding respectively to LD50/15, LD50/10, and LD50/5 (i.p. LD50=11.48 mg/kg bwt) for seven consecutive days. Results revealed a marked decrease in body weight gain and food intake, and an increase in absolute and relative kidney weights in ABV D2 and D3 treated mice compared with controls. Furthermore, ABV D2 and D3 resulted in a significant increase in serum creatinine, urea, and uric acid. ABV-induced oxidative stress was evidenced by a significant increase in kidney MDA level, and a significant depletion in kidney GSH level, and catalase activity. Meanwhile, no marked changes in the above-mentioned parameters were noticed in ABV D1. Accordingly, the adverse nephrotoxic effect of ABV was proved by the dose-dependent kidney histological changes. In summary, the results of the present study evidence that ABV at doses of 1.14 (D2) and 2.28 mg/kg body weight (bwt) can cause marked changes in kidney biochemical and major antioxidant markers, and histological architecture.

Insight into the Toxicological and Pathophysiological Effects of Moroccan Vipers' Venom: Assessing the Efficacy of Commercial Antivenom for Neutralization

Morocco is one of the richest countries in biodiversity in the Mediterranean region, especially in its ophidian fauna. In total, there are eight species of venomous snakes, with seven belonging to the Viperidae family, responsible for 67.2% of severe envenomation cases in the country. Cerastes cerastes, Daboia mauritanica and Bitis arietans are considered among the most venomous vipers whose bites cause high levels of morbidity, disability or mortality. Despite their wide distribution in the kingdom, the incidence of these snakebites remains poorly understood and largely underestimated. Moreover, intraspecific variations in the venom composition significantly affect the effectiveness of antivenoms. Due to the unavailability of locally produced antivenoms, we evaluated the efficacy of Inoserp-MENA, the only available antivenom in Morocco, against C. cerastes, D. mauritanica and B. arietans. First, we conducted a comprehensive characterization of these venoms, including an LD₅₀ test to examine their toxicity and SDS-PAGE as a technique to analyze the enzymes responsible for biological activities, such as hemorrhagic and edematous activities and myotoxicity, which generate physiopathological effects in the skin, paws and muscles of envenomed mice. Then, we assessed the ability of Inoserp-MENA antivenom to neutralize the toxic activities of Moroccan vipers. Our results indicate that the venom of C. cerastes, D. mauritanica and B. arietans are toxic, causing severe alterations such as edema, myotoxicity, myonecrosis and significant hemorrhages with the formation of hemorrhagic foci. C. cerastes venom is more dangerous in terms of lethality and hemorrhages, while B. arietans venom is more edematous. The effects of C. cerastes venom were effectively neutralized, but Inoserp-MENA antivenom failed to protect mice against the toxic effects induced by B. arietans and D. mauritanica venom. The study reveals alarming shortcomings in the effectiveness of the current commercially available antivenom's dosage and neutralization capabilities, highlighting the urgent need to develop a region-specific viper envenomation therapy.

Historical Perspective of the Characterization of Conotoxins Targeting Voltage-Gated Sodium Channels

Marine toxins have potent actions on diverse sodium ion channels regulated by transmembrane voltage (voltage-gated ion channels) or by neurotransmitters (nicotinic acetylcholine receptor channels). Studies of these toxins have focused on varied aspects of venom peptides ranging from evolutionary relationships of predator and prey, biological actions on excitable tissues, potential application as pharmacological intervention in disease therapy, and as part of multiple experimental approaches towards an understanding of the atomistic characterization of ion channel structure. This review examines the historical perspective of the study of conotoxin peptides active on sodium channels gated by transmembrane voltage, which has led to recent advances in ion channel research made possible with the exploitation of the diversity of these marine toxins.

Synthesized peptide analogs from Eumenes pomiformis (Hymenoptera: Eumenidae) venom reveals their antibiotic and pesticide activity potential

One natural antimicrobial peptide (EpVP2a, Eumenes pomiformis Venom Peptide 2a) found in the venom of a potter wasp (Eumenes pomiformis) and six analogs were synthesized and tested to compare their antimicrobial, antifungal, pesticide, and hemolytic activity with the wild type. Our results indicated that while the original peptide and the synthetic analogs had no antifungal activity or anti-bacterial activity against Pseudomonas aeruginosa, the original peptide and the analog with substitution of the aspartic acid on the sequence by a lysine (EpVP2a-D2K2) had activity against Escherichia coli, Staphylococcus aureus and Bacillus subtilis. This same analog also shows significant insecticide activity. The analog with substitution of lysine with a slightly smaller ornithine had activity against E. coli and B. subtilis. All analogs show low hemolytic activity compared to the natural peptide. The peptide with a reverse sequence to the natural one (EpVp2a Retro) shows low helix structure which can also explain why it has no antibacterial activity and low hemolytic activity. Circular dichroism spectra show that these peptides form an alpha helix structure and their amino acid positions predict an amphipathic nature.

Equipped for Sexual Stings? Male-Specific Venom Peptides in Euscorpius italicus

In the animal kingdom, intraspecific variation occurs, for example, between populations, different life stages, and sexes. For venomous animals, this can involve differences in their venom composition. In cases where venom is utilized in the context of mating, the differences in composition might be driven by sexual selection. In this regard, the genus Euscorpius is a promising group for further research, as some of these scorpions exhibit a distinct sexual dimorphism and are known to perform a sexual sting during mating. However, the venom composition of this genus remains largely unexplored. Here, we demonstrate that Euscorpius italicus exhibits a male-specific venom composition, and we identify a large fraction of the substances involved. The sex specificity of venom peptides was first determined by analyzing the presence/absence patterns of ion signals in MALDI-TOF mass spectra of venom samples from both sexes and juveniles. Subsequently, a proteo-transcriptomic analysis provided sequence information on the relevant venom peptides and their corresponding precursors. As a result, we show that several potential toxin precursors are down-regulated in male venom glands, possibly to reduce toxic effects caused to females during the sexual sting. We have identified the precursor of one of the most prominent male-specific venom peptides, which may be an ideal candidate for activity tests in future studies. In addition to the description of male-specific features in the venom of E. italicus, this study also includes a general survey of venom precursors in this species.

Astragalus–Scorpion Drug Pair Inhibits the Development of Prostate Cancer by Regulating GDPD4-2/PI3K/AKT/mTOR Pathway and Autophagy

Objective: Prostate cancer (PCa) is an epithelial malignancy of the prostate that currently lacks effective treatment. Traditional Chinese medicine (TCM) can play an anticancer role through regulating the immune system, anti-tumor angiogenesis, regulating tumor cell apoptosis, autophagy dysfunction, and other mechanisms. This study attempted to explore the active ingredients and potential mechanism of action of the Astragalus–Scorpion (A–S) drug pair in PCa, in order to provide new insights into the treatment of PCa.

Methods: Network pharmacology was used to analyze the A–S drug pair and PCa targets. Bioinformatics analysis was used to analyze the LncRNAs with significant differences in PCa. The expression of LC3 protein was detected by immunofluorescence. CCK8 was used to detect cell proliferation. The expressions of GDPD4-2, AC144450.1, LINC01513, AC004009.2, AL096869.1, AP005210.1, and BX119924.1 were detected by RT-qPCR. The expression of the PI3K/AKT/mTOR pathway and autophagy-related proteins were detected by western blot. LC-MS/MS was used to identify the active components of Astragalus and Scorpion.

Results: A–S drug pair and PCa have a total of 163 targets, which were mainly related to the prostate cancer and PI3K/AKT pathways. A–S drug pair inhibited the formation of PCa, promoted the expression of LC3Ⅱ and Beclin1 proteins, and inhibited the expression of P62 and PI3K–AKT pathway proteins in PCa mice. Astragaloside IV and polypeptide extract from scorpion venom (PESV) were identified as the main active components of the A–S drug pair. GDPD4-2 was involved in the treatment of PCa by Astragaloside IV-PESV. Silencing GDPD4-2 reversed the therapeutic effects of Astragaloside IV-PESV by regulating the PI3K/AKT/mTOR pathway.

Conclusion: Astragaloside IV-PESV is the main active components of A–S drug pair treated PCa by regulating the GDPD4-2/PI3K–AKT/mTOR pathway and autophagy.

Bothrops bilineatus: An Arboreal Pitviper in the Amazon and Atlantic Forest

The two-striped forest-pitviper (Bothrops bilineatus) is an arboreal snake that is currently represented by two subspecies (B. b. bilineatus and B. b. smaragdinus) that comprise a species complex, and its distribution is in the Amazon and the Atlantic Forest. The rarity of encounters with this snake is reflected in the low occurrence of cases of snakebites throughout its geographic distribution and the resulting low number of published clinical reports. However, in some areas, B. bilineatus proves to be more frequent and causes envenomations in a greater proportion. Herein, we review the main aspects of the species complex B. bilineatus, including its biology, ecology, taxonomy, morphology, genetic and molecular studies, geographic distribution, conservation status, venom, pathophysiology and clinical aspects, and epidemiology. In addition, the different antivenoms available for the treatment of envenomations caused by B. bilineatus are presented along with suggestions for future studies that are needed for a better understanding of the snakebites caused by this snake.

Intraspecific variability of the Central American rattlesnake (Crotalus simus) venom and its usefulness to obtain a representative standard venom

Snake venoms are mixtures of proteins whose physicochemical features confer them toxicity and immunogenicity. Animals (e.g., horses or sheep) immunized with snake venoms produce antibodies towards the venom proteins. Since these antibodies can neutralize the venom toxicity, they have been used to formulate snake antivenoms. The efficacy of the antivenoms is widely accepted, and standard venoms are expected to be representative of the snake's population that inhabit in the region where the antivenom is intended to be used. The representativeness of a single venom collected from a Crotalus simus snake, and its usefulness as standard venom to produce an antivenom is evaluated. The use of an "average venom" might be as representative of the population intended to be used, as the standard venom composed by many venom samples. Variations in the relative abundance concentration of crotoxin in the C. simus leads to different clinical manifestations, as well as differences in the neutralization efficacy of the antivenoms. A monovalent anti-Cs antivenom was produced from a single venom C. simus specimen, and its efficacy in neutralizing the lethal activity of 30 C. simus snakes was tested. Despite the variations in the relative abundance content of crotoxin found in the proteomes, the monovalent anti-Cs antivenom was successful in neutralize the toxicity caused by the variations on the venom composition of three different snake population used. Interestingly, it seems that the sex is not a key factor in the lethality of the venoms tested. The concept of representative venom mixtures for immunization should be revised for the case of C. simus on the populations found in Costa Rica, since it might use as less as one representative individual whose venom covers the mainly toxic enzymes.