Biomedical and Biotechnological Potential of Animal Venoms: Bothrops Snake Venoms and their Antimicrobial Applications

The pursuit of novel treatment alternatives to address the accumulated resistance to antimicrobials over the years has prompted the scientific community to explore biodiversity, particularly animal venom, as a potential source of new antimicrobial drugs. Snake venoms, with their complex mixtures of components, are particularly promising targets for investigation in this regard. The search for novel molecules exhibiting antimicrobial activity against multidrug-resistant strains is of paramount importance for public health and numerous research groups worldwide. High expectations within the healthcare field are supported by the scientific literature, which highlights the potential development of innovative drugs through in vivo and in vitro application, depending on dose titration. Snake venoms and their molecules and peptides offer exponential possibilities for biotechnological applications as antimicrobial agents. However, many uncertainties and unexplored avenues remain, presenting opportunities for discoveries and research.

Bothrops jararacussu snake venom lectin induces mast cell activation and vascular permeability enhance in an animal model

Bothrops species trigger an acute inflammatory response in victims, with activated leukocytes releasing several mediators that may contribute to local and systemic effects. The effects of BjcuL, a lectin isolated from B. jararacussu snake venom, on mast cells and vasopermeability were investigated in this study. BjcuL activates mast cells and increases vasopermeability through the involvement of histamine and platelet activating factor, which may play a role in the victims' acute inflammatory reaction.

Synergism of in vitro plasmodicidal activity of phospholipase A2 isoforms isolated from panamanian Bothrops asper venom

Bothrops asper is one of the most important snake species in Central America, mainly because of its medical importance in countries like Ecuador, Panama and Costa Rica, where this species causes a high number of snakebite accidents. Several basic phospholipases A₂ (PLA₂s) have been previously characterized from B. asper venom, but few studies have been carried out with its acidic isoforms. In addition, since snake venom is a rich source of bioactive substances, it is necessary to investigate the biotechnological potential of its components. In this context, this study aimed to carry out the biochemical characterization of PLA₂ isoforms isolated from B. asper venom and to evaluate the antiparasitic potential of these toxins. The venom and key fractions were subjected to different chromatographic steps, obtaining nine PLA₂s, four acidic ones (BaspAc-I, BaspAc-II, BaspAc-III and BaspAc-IV) and five basic ones (BaspB-I, BaspB-II, BaspB-III, BaspB-IV and BaspB-V). The isoelectric points of the acidic PLA₂s were also determined, which presented values ranging between 4.5 and 5. The findings indicated the isolation of five unpublished isoforms, four Asp49-PLA, corresponding to the group of acidic isoforms, and one Lys49-PLA₂-like. Acidic PLA₂s catalyzed the degradation of all substrates evaluated; however, for the basic PLA₂s, there was a preference for phosphatidylglycerol and phosphatidic acid. The antiparasitic potential of the toxins was evaluated, and the acidic PLA₂s demonstrated action against the epimastigote forms of T. cruzi and promastigote forms of L. infantum, while the basic PLA₂s BaspB-II and BaspB-IV showed activity against P. falciparum. The results indicated an increase of up to 10 times in antiplasmodial activity, when the Asp49-PLA₂ and Lys49-PLA₂ were associated with one another, denoting synergistic action between these PLA₂ isoforms. These findings correspond to the first report of synergistic antiplasmodial action for svPLA₂s, demonstrating that these molecules may be important targets in the search for new antiparasitic agents.

Isolation, Biochemical Characterization and Antiparasitic Activity of BmatTX-IV, A Basic Lys49-Phospholipase A2 from the Venom of Bothrops mattogrossensis from Paraguay

Background:

Functional and structural diversity of proteins of snake venoms is coupled with a wide repertoire of pharmacological effects. Snake venoms are targets of studies linked to searching molecules with biotechnological potential.

Methods:

A homologue phospholipase A2 (BmatTX-IV) was obtained using two chromatographic techniques. Mass spectrometry and two-dimensional gel electrophoresis were used to determine the molecular mass and isoelectric point, respectively. By means of Edman degradation chemistry, it was possible to obtain the partial sequence of amino acids that comprise the isolated toxin. Trypanocidal, leishmanicidal and cytoxic activity against Trypanosoma cruzi, Leishmania infantum and murine fibrobasts was determinated.

Results:

Combination of both chromatographic steps used in this study demonstrated efficacy to obtain the PLA2-Lys49. BmatTX-IV showed molecular mass and isoelectric point of 13.55 kDa and 9.3, respectively. Amino acid sequence of N-terminal region (51 residues) shows the presence of Lys49 residue at position 49, a distinctive trait of enzymatically inactive PLA2. Bothrops mattogrossensis snake venom showed IC50 values of 11.9 μg/mL against Leishmania infantum promastigotes and of 13.8 μg/mL against Trypanosoma cruzi epimastigotes, respectively. On the other hand, the venom showed a high cytotoxic activity (IC50 value of 16.7 μg/mL) against murine fibroblasts, whereas the BmatTX-IV showed IC50 value of 81.2 μg/mL.

Conclusion:

Physicochemical and biological characterization of snake venoms components is critically important, since these complex mixtures provide a source of molecules with antiparasitic potential, making further studies necessary to identify and characterize components with higher efficacy and selectivity.

Biochemical characterization of a phospholipase A2 homologue from the venom of the social wasp Polybia occidentalis

Background

Wasp venoms constitute a molecular reservoir of new pharmacological substances such as peptides and proteins, biological property holders, many of which are yet to be identified. Exploring these sources may lead to the discovery of molecules hitherto unknown. This study describes, for the first time in hymenopteran venoms, the identification of an enzymatically inactive phospholipase A₂ (PLA₂) from the venom of the social wasp Polybia occidentalis.

Methods

P. occidentalis venom was fractioned by molecular exclusion and reverse phase chromatography. For the biochemical characterization of the protein, 1D and 2D SDS-PAGE were performed, along with phospholipase activity assays on synthetic substrates, MALDI-TOF mass spectrometry and sequencing by Edman degradation.

Results

The protein, called PocTX, was isolated using two chromatographic steps. Based on the phospholipase activity assay, electrophoresis and mass spectrometry, the protein presented a high degree of purity, with a mass of 13,896.47 Da and a basic pI. After sequencing by the Edman degradation method, it was found that the protein showed a high identity with snake venom PLA₂ homologues.

Conclusion

This is the first report of an enzymatically inactive PLA₂ isolated from wasp venom, similar to snake PLA₂ homologues.

Inhibition of the Myotoxicity Induced by Bothrops jararacussu Venom and Isolated Phospholipases A2 by Specific Camelid Single-Domain Antibody Fragments

Antivenoms, produced using animal hyperimmune plasma, remains the standard therapy for snakebites. Although effective against systemic damages, conventional antivenoms have limited efficacy against local tissue damage. Additionally, the hypersensitivity reactions, often elicited by antivenoms, the high costs for animal maintenance, the difficulty of producing homogeneous lots, and the instability of biological products instigate the search for innovative products for antivenom therapy. In this study, camelid antibody fragments (VHH) with specificity to Bothropstoxin I and II (BthTX-I and BthTX-II), two myotoxic phospholipases from Bothrops jararacussu venom, were selected from an immune VHH phage display library. After biopanning, 28 and 6 clones recognized BthTX-I and BthTX-II by ELISA, respectively. Complementarity determining regions (CDRs) and immunoglobulin frameworks (FRs) of 13 VHH-deduced amino acid sequences were identified, as well as the camelid hallmark amino acid substitutions in FR2. Three VHH clones (KF498607, KF498608, and KC329718) were capable of recognizing BthTX-I by Western blot and showed affinity constants in the nanomolar range against both toxins. VHHs inhibited the BthTX-II phospholipase A2 activity, and when tested for cross-reactivity, presented specificity to the Bothrops genus in ELISA. Furthermore, two clones (KC329718 and KF498607) neutralized the myotoxic effects induced by B. jararacussu venom, BthTX-I, BthTX-II, and by a myotoxin from Bothrops brazili venom (MTX-I) in mice. Molecular docking revealed that VHH CDRs are expected to bind the C-terminal of both toxins, essential for myotoxic activity, and to epitopes in the BthTX-II enzymatic cleft. Identified VHHs could be a biotechnological tool to improve the treatment for snake envenomation, an important and neglected world public health problem.

Action of two phospholipases A2 purified from Bothrops alternatus snake venom on macrophages

The in vitro effects of BaltTX-I, a catalytically inactive Lys49 variant of phospholipase A2 (PLA2), and BaltTX-II, an Asp49 catalytically active PLA2 isolated from Bothrops alternatus snake venom, on thioglycollate-elicited macrophages (TG-macrophages) were investigated. At non-cytotoxic concentrations, the secretory PLA2 BaltTX-I but not BaltTX-II stimulated complement receptor-mediated phagocytosis. Pharmacological treatment of TG-macrophages with staurosporine, a protein kinase C (PKC) inhibitor, showed that this kinase is involved in the increase of serum-opsonized zymosan phagocytosis induced by BaltTX-I but not BaltTX-II secretory PLA2, suggesting that PKC may be involved in the stimulatory effect of this toxin in serum-opsonized zymosan phagocytosis. Moreover, BaltTX-I and -II induced superoxide production by TG-macrophages. This superoxide production stimulated by both PLA2s was abolished after treatment of cells with staurosporine, indicating that PKC is an important signaling pathway for the production of this radical. Our experiments showed that, at non-cytotoxic concentrations, BaltTX-I may upregulate phagocytosis via complement receptors, and that both toxins upregulated the respiratory burst in TG-macrophages.

ESI-MS/MS identification of a bradykinin-potentiating peptide from Amazon Bothrops atrox snake venom using a hybrid Qq-oaTOF mass spectrometer

A bradykinin-potentiating peptide (BPP) from Amazon Bothrops atrox venom with m/z 1384.7386 was identified and characterized by collision induced dissociation (CID) using an ESI-MS/MS spectra obtained in positive ion mode on a hybrid Qq-oaTOF mass spectrometer, Xevo G2 QTof MS (Waters, Manchester, UK). De novo peptide sequence analysis of the CID fragmentation spectra showed the amino acid sequence ZKWPRPGPEIPP, with a pyroglutamic acid and theoretical monoisotopic m/z 1384.7378, which is similar to experimental data, showing a mass accuracy of 0.6 ppm. The peptide is homologous to other BPP from Bothrops moojeni and was named as BPP-BAX12.

Local and systemic biochemical alterations induced by Bothrops atrox snake venom in mice

The local and systemic alterations induced by Bothrops atrox snake venom (BaV) injection in mice were studied. BaV induced superoxide production by migrated neutrophils, mast cell degranulation and phagocytosis by macrophages. Moreover, BaV caused hemorrhage in dorsum of mice after 2hr post- injection. Three hours post-injection in gastrocnemius muscle, we also observed myonecrosis, which was assessed by the determination of serum and tissue CK besides the release of urea, but not creatinine and uric acid, indicating kidney alterations. BaV also induced the release of LDH and transaminases (ALT and AST) indicating tissue and liver abnormalities. In conclusion, the data indicate that BaV induces events of local and systemic importance.

Snake venom L-amino acid oxidases: some consideration about their functional characterization

Snake Venom L-amino acid oxidases (LAAOs E.C. 1.4.3.2) are flavoenzymes broadly found in various snake venom compositions. LAAOs have become an attractive subject for molecular biology, biochemistry, physiology and medicine due to their actions on various cells and biological effects on platelets, apoptosis, hemorrhage and others. In this review we try to summarize some of these reports, with special emphasis on apoptosis, anti-protozoa, bactericidal and anti-viral activities.