Immunomodulatory properties of molecules from animal venoms

Interrogating stonefish venom: small molecules present in envenomation caused by Synanceia spp

The stonefish Synanceia verrucosa and Synanceia horrida are arguably the most venomous fish species on earth and the culprits of severe stings in humans globally. Investigation into the venoms of these two species has mainly focused on protein composition, in an attempt to identify the most medically relevant proteins, such as the lethal verrucotoxin and stonustoxin components. This study, however, focused on medically relevant small molecules, and through nuclear magnetic resonance, mass spectroscopy, and fractionation techniques, we discovered and identified the presence of three molecules new to stonefish venom, namely γ-aminobutyric acid (GABA), choline and 0-acetylcholine, and provide the first report of GABA identified in a fish venom. Analysis of the crude venoms on human nicotinic acetylcholine receptors (nAChRs) and a GABAA receptor (GABAAR) showed S. horrida venom could activate neuronal (α7) and adult muscle-type (α1β1δε) nAChRs, while both crude S. horrida and S. verrucosa venoms activated the GABAAR (α1β2γ2). Cytotoxicity studies in immunologically relevant cells (human PBMCs) indicated the venoms possess cell-specific cytotoxicity and analysis of the venom fractions on Na+ channel subtypes involved in pain showed no activity. This work highlights the need to further investigate the small molecules found in venoms to help understand the mechanistic pathways of clinical symptoms for improved treatment of sting victims, in addition to the discovery of potential drug leads.

Histopathological characterization of skin and muscle lesions induced by lionfish (Pterois volitans) venom in a murine experimental model

Background

Fish venoms have been poorly characterized and the available information about their composition suggests they are uncomplicated secretions that, combined with epidermal mucus, could induce an inflammatory reaction, excruciating pain, and, in some cases, local tissue injuries.

Methods

In this study, we characterized the 24-hour histopathological effects of lionfish venom in a mouse experimental model by testing the main fractions obtained by size exclusion-HPLC. By partial proteomics analysis, we also correlated these in vivo effects with the presence of some potentially toxic venom components.

Results

We observed a strong lesion on the skin and evident necrosis in the skeletal muscle. None of the tissue-damaging effects were induced by the fraction containing cytolysins, membrane pore-forming toxins ubiquitously present in species of scorpionfish, stonefish, and lionfish, among others. On the contrary, injuries were associated with the presence of other components, which have remained practically ignored so far. This is the case of an abundant protein, present in venom, with homology to a Golgi-associated plant pathogenic protein 1-like (GAPR1), which belongs to the same protein superfamily as venom CRISPs and insect allergens.

Conclusion

This GAPR1-like protein and the hyaluronidase are probably responsible for the hemostasis impairment and hemorrhagic lesions observed in mouse skin, whereas muscle injuries can be indirectly caused by a combination of inflammatory and hemorrhagic events. More information is required to establish the components accountable for the myonecrotic effect.

Microscopic marvels: Decoding the role of micropeptides in innate immunity

The innate immune response is under selection pressures from changing environments and pathogens. While sequence evolution can be studied by comparing rates of amino acid mutations within and between species, how a gene's birth and death contribute to the evolution of immunity is less known. Short open reading frames, once regarded as untranslated or transcriptional noise, can often produce micropeptides of <100 amino acids with a wide array of biological functions. Some micropeptide sequences are well conserved, whereas others have no evolutionary conservation, potentially representing new functional compounds that arise from species-specific adaptations. To date, few reports have described the discovery of novel micropeptides of the innate immune system. The diversity of immune-related micropeptides is a blind spot for gene and functional annotation. Immune-related micropeptides represent a potential reservoir of untapped compounds for understanding and treating disease. This review consolidates what is currently known about the evolution and function of innate immune-related micropeptides to facilitate their investigation.

Potential therapeutic biomolecules of hymenopteran venom against SARS-CoV-2 from Egyptian patients

The therapeutic potential of insect-derived bioactive molecules as anti-SARS-CoV-2 agents has shown promising results. Hymenopteran venoms, notably from Apis mellifera (honeybee) and Vespa orientalis (oriental wasp), were examined for the first time in an in vitro setting for their potential anti-COVID-19 activity. This assessment utilized an immunodiagnostic system to detect the SARS-CoV-2 nucleocapsid antigen titer reduction. Further analyses, including cytotoxicity assays, plaque reduction assays, and in silico docking-based screening, were performed to evaluate the efficacy of the most potent venom. Results indicated that bee and wasp venoms contain bioactive molecules with potential therapeutic effects against SARS-CoV-2.Nevertheless, the wasp venom exhibited superior efficacy compared to bee venom, achieving a 90% maximal (EC90) concentration effect of antigen depletion at 0.184 mg/mL, in contrast to 2.23 mg/mL for bee venom. The cytotoxicity of the wasp venom was assessed on Vero E6 cells 48 h post-treatment using the MTT assay. The CC 50 of the cell growth was 0.16617 mg/mL for Vero E6 cells. The plaque reduction assay of wasp venom revealed 50% inhibition (IC50) at a 0.208 mg/mL concentration. The viral count at 50% inhibition was 2.5 × 104 PFU/mL compared to the initial viral count of 5 × 104 PFU/mL. In silico data for the wasp venom revealed a strong attraction to binding sites on the ACE2 protein, indicating ideal interactions. This substantiates the potential of wasp venom as a promising viral inhibitor against SARS-CoV-2, suggesting its consideration as a prospective natural preventive and curative antiviral drug. In conclusion, hymenopteran venoms, particularly wasp venom, hold promise as a source of potential therapeutic biomolecules against SARS-CoV-2. More research and clinical trials are needed to evaluate these results and investigate their potential for translation into innovative antiviral therapies.

Effect of animal venom toxins on the main links of the homeostasis of mammals (Review)

The human body is affected by environmental factors. The dynamic balance between the organism and its environment results from the influence of natural, anthropogenic and social aspects. The factors of exogenous origin determine development of adaptive changes. The present article summarises the mechanisms of animal venom toxins and homeostasis disruption in the body of mammals. The mechanisms underlying pathological changes are associated with shifts in biochemical reactions. Components of the immune, nervous and endocrine systems are key in the host defense and adaptation processes in response to venom by triggering signalling pathways (PI3kinase pathway, arachidonic acid cascade). Animal venom toxins initiate the development of inflammatory processes, the synthesis of pro-inflammatory mediators (cytokines), ROS, proteolytic enzymes, activate the migration of leukocytes and macrophages. Keratinocytes and endothelial cells act as protective barriers under the action of animal venom toxins on the body of mammals. In addition, the formation of pores in cell membranes, structural changes in cell ion channels are characteristic of the action of animal venom toxins.

The Identification of a Novel Spider Toxin Peptide, Lycotoxin-Pa2a, with Antibacterial and Anti-Inflammatory Activities

With the increasing challenge of controlling infectious diseases due to the emergence of antibiotic-resistant strains, the importance of discovering new antimicrobial agents is rapidly increasing. Animal venoms contain a variety of functional peptides, making them a promising platform for pharmaceutical development. In this study, a novel toxin peptide with antibacterial and anti-inflammatory activities was discovered from the spider venom gland transcriptome by implementing computational approaches. Lycotoxin-Pa2a (Lytx-Pa2a) showed homology to known-spider toxin, where functional prediction indicated the potential of both antibacterial and anti-inflammatory peptides without hemolytic activity. The colony-forming assay and minimum inhibitory concentration test showed that Lytx-Pa2a exhibited comparable or stronger antibacterial activity against pathogenic strains than melittin. Following mechanistic studies revealed that Lytx-Pa2a disrupts both cytoplasmic and outer membranes of bacteria while simultaneously inducing the accumulation of reactive oxygen species. The peptide exerted no significant toxicity when treated to human primary cells, murine macrophages, and bovine red blood cells. Moreover, Lytx-Pa2a alleviated lipopolysaccharide-induced inflammation in mouse macrophages by suppressing the expression of inflammatory mediators. These findings not only suggested that Lytx-Pa2a with dual activity can be utilized as a new antimicrobial agent for infectious diseases but also demonstrated the implementation of in silico methods for discovering a novel functional peptide, which may enhance the future utilization of biological resources.

Protein and peptide profiles of rats' organs in scorpion envenomation

Problem of scorpion envenomation becomes more alarming each year. Main effects of scorpion venom are commonly believed to be related to its neurotoxic properties, yet severe symptoms may also be developed due to the uncontrolled enzymatic activity and formation of various bioactive molecules, including middle-mass molecules (MMMs). MMMs are considered as endogenous intoxication markers, their presence may indicate multiple organ failure. Scorpions, belong to the Leiurus macroctenus species, are very dangerous, nevertheless, effects of their venom on protein and peptide composition within the tissues remains unclear. In this work we have focused the attention on changes in protein and MMM levels and peptide composition in various organs during Leiurus macroctenus envenomation. The results revealed a decrease in protein level during envenomation as well as a significant increment of MMM₂₁₀ and MMM₂₅₄ levels in all assessed organs. Quantitative and qualitative compositions of various protein and peptide factions were continually changing. All of this may suggest that Leiurus macroctenus sting causes considerable destruction of cell microenvironment across all essential organs, providing systemic envenomation. In addition, MMM level increment may indicate endogenous intoxication development. Peptides, formed during envenomation, may possess various bioactive properties, analysis of which constitutes an area of further studies.

Identification and Characterization of a Novel Cathelicidin from Hydrophis cyanocinctus with Antimicrobial and Anti-Inflammatory Activity

The abuse of antibiotics and lack of new antibacterial drugs has led to the emergence of superbugs that raise fears of untreatable infections. The Cathelicidin family of antimicrobial peptide (AMP) with varying antibacterial activities and safety is considered to be a promising alternative to conventional antibiotics. In this study, we investigated a novel Cathelicidin peptide named Hydrostatin-AMP2 from the sea snake Hydrophis cyanocinctus. The peptide was identified based on gene functional annotation of the H. cyanocinctus genome and bioinformatic prediction. Hydrostatin-AMP2 showed excellent antimicrobial activity against both Gram-positive and Gram-negative bacteria, including standard and clinical Ampicillin-resistant strains. The results of the bacterial killing kinetic assay demonstrated that Hydrostatin-AMP2 had faster antimicrobial action than Ampicillin. Meanwhile, Hydrostatin-AMP2 exhibited significant anti-biofilm activity including inhibition and eradication. It also showed a low propensity to induce resistance as well as low cytotoxicity and hemolytic activity. Notably, Hydrostatin-AMP2 apparently decreased the production of pro-inflammatory cytokines in the LPS-induced RAW264.7 cell model. To sum up, these findings indicate that Hydrostatin-AMP2 is a potential peptide candidate for the development of new-generation antimicrobial drugs fighting against antibiotic-resistant bacterial infections.

The Activity of Metalloproteases and Serine Proteases in Various Organs after Leiurus macroctenus Envenomation

Background

Scorpion stings may be life-threatening since their venoms are comprised of a wide range of toxins and other bioactive molecules, such as enzymes. At the same time, scorpion envenomation may increase matrix metalloproteases (MMPs) levels, which enhance proteolytic tissue destruction by venom. However, investigations on the impact of many scorpions' venoms, such as those of Leiurus macroctenus, on tissue proteolytic activity and MMP levels have not yet been conducted.

Methods and Results

The present study aimed to examine the total proteolysis levels in various organs after Leiurus macroctenus envenomation and evaluate the metalloproteases and serine proteases' contributions to the total proteolytic activity. Changes in MMPs and TIMP-1 levels were tested as well. Envenomation led to a significant increase in proteolytic activity levels in all assessed organs, mostly in the heart (by 3.34 times) and lungs (by 2.25 times).

Conclusions

Since EDTA presence showed a noticeable decrease in total proteolytic activity level, metalloproteases appeared to play a prominent role in total proteolytic activity. At the same time, MMPs and TIMP-1 levels were increased in all assessed organs, suggesting that Leiurus macroctenus envenomation causes systemic envenomation, which may induce multiple organ abnormalities, mostly because of the uncontrolled metalloprotease activity.

Purification and Characterization of a Novel Factor of Crotoxin Inter-CRO (V-1), a New Phospholipase A2 Isoform from Crotalus durissus collilineatus Snake Venom Using an In Vitro Neuromuscular Preparation

The fractionation of Crotalus durissus collilineatus whole venom through an HPLC chromatographic method enabled the purification of a new V-1 neurotoxin. Inter-CRO (V-1) presents similarity in its primary structure to crotoxin B (CB), suggesting another isoform of this toxin. The aim of this study was to compare V-1 to the crotoxin complex (CA/CB) and CB to elucidate aspects related to its functionality. The homogeneity of the purified protein was confirmed with a molecular mass of 1425.45 Da, further verified by mass spectrometry. The sequence of the protein showed high similarity to other viperid snake venom PLA2 proteins. The results of this study report that V-1 is an uncharacterized novel toxin with different biological activities from CB. V-1 maintained catalytic activity but presented neurotoxic activity as observed by the 2.5-fold increase in twitch tension record compared to control values on isolated muscle cells.

Modern venomics-Current insights, novel methods, and future perspectives in biological and applied animal venom research

Venoms have evolved >100 times in all major animal groups, and their components, known as toxins, have been fine-tuned over millions of years into highly effective biochemical weapons. There are many outstanding questions on the evolution of toxin arsenals, such as how venom genes originate, how venom contributes to the fitness of venomous species, and which modifications at the genomic, transcriptomic, and protein level drive their evolution. These questions have received particularly little attention outside of snakes, cone snails, spiders, and scorpions. Venom compounds have further become a source of inspiration for translational research using their diverse bioactivities for various applications. We highlight here recent advances and new strategies in modern venomics and discuss how recent technological innovations and multi-omic methods dramatically improve research on venomous animals. The study of genomes and their modifications through CRISPR and knockdown technologies will increase our understanding of how toxins evolve and which functions they have in the different ontogenetic stages during the development of venomous animals. Mass spectrometry imaging combined with spatial transcriptomics, in situ hybridization techniques, and modern computer tomography gives us further insights into the spatial distribution of toxins in the venom system and the function of the venom apparatus. All these evolutionary and biological insights contribute to more efficiently identify venom compounds, which can then be synthesized or produced in adapted expression systems to test their bioactivity. Finally, we critically discuss recent agrochemical, pharmaceutical, therapeutic, and diagnostic (so-called translational) aspects of venoms from which humans benefit.

Future Directions for the Discovery of Natural Product-Derived Immunomodulating Drugs

Drug discovery from natural sources is going through a renaissance, having spent many decades in the shadow of synthetic molecule drug discovery, despite the fact that natural product-derived compounds occupy a much greater chemical space than those created through synthetic chemistry methods. With this new era comes new possibilities, not least the novel targets that have emerged in recent times and the development of state-of-the-art technologies that can be applied to drug discovery from natural sources. Although progress has been made with some immunomodulating drugs, there remains a pressing need for new agents that can be used to treat the wide variety of conditions that arise from disruption, or over-activation, of the immune system; natural products may therefore be key in filling this gap. Recognising that, at present, there is no authoritative article that details the current state-of-the-art of the immunomodulatory activity of natural products, this in-depth review has arisen from a joint effort between the International Union of Basic and Clinical Pharmacology (IUPHAR) Natural Products and Immunopharmacology, with contributions from a Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation number of world-leading researchers in the field of natural product drug discovery, to provide a "position statement" on what natural products has to offer in the search for new immunomodulatory argents. To this end, we provide a historical look at previous discoveries of naturally occurring immunomodulators, present a picture of the current status of the field and provide insight into the future opportunities and challenges for the discovery of new drugs to treat immune-related diseases.