Scorpion Peptides and Ion Channels: An Insightful Review of Mechanisms and Drug Development

Antivenom potential of the latex of Jatropha mutabilis baill. (Euphorbiaceae) against Tityus stigmurus venom: Evaluating its ability to neutralize toxins and local effects in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Species of the Jatropha genus (Euphorbiaceae) are used indiscriminately in traditional medicine to treat accidents involving venomous animals. Jatropha mutabilis Baill., popularly known as "pinhão-de-seda," is found in the semi-arid region of Northeastern Brazil. It is widely used as a vermifuge, depurative, laxative, and antivenom.

AIM OF THE STUDY

Obtaining the phytochemical profile of the latex of Jatropha mutabilis (JmLa) and evaluate its acute oral toxicity and inhibitory effects against the venom of the scorpion Tityus stigmurus (TstiV).

MATERIALS AND METHODS

The latex of J. mutabilis (JmLa) was obtained through in situ incisions in the stem and characterized using HPLC-ESI-QToF-MS. Acute oral toxicity was investigated in mice. The protein profile of T. stigmurus venom was obtained by electrophoresis. The ability of latex to interact with venom components (TstiV) was assessed using SDS-PAGE, UV-Vis scanning spectrum, and the neutralization of fibrinogenolytic and hyaluronidase activities. Additionally, the latex was evaluated in vivo for its ability to inhibit local edematogenic and nociceptive effects induced by the venom.

RESULTS

The phytochemical profile of the latex revealed the presence of 75 compounds, including cyclic peptides, glycosides, phenolic compounds, alkaloids, coumarins, and terpenoids, among others. No signs of acute toxicity were observed at a dose of 2000 mg/kg (p.o.). The latex interacted with the protein profile of TstiV, inhibiting the venom's fibrinogenolytic and hyaluronidase activities by 100%. Additionally, the latex was able to mitigate local envenomation effects, reducing nociception by up to 56.5% and edema by up to 50% compared to the negative control group.

CONCLUSIONS

The latex of Jatropha mutabilis exhibits a diverse phytochemical composition, containing numerous classes of metabolites. It does not present acute toxic effects in mice and has the ability to inhibit the enzymatic effects of Tityus stigmurus venom in vitro. Additionally, it reduces nociception and edema in vivo. These findings corroborate popular reports regarding the antivenom activity of this plant and indicate that the latex has potential for treating scorpionism.

Harnessing the potency of scorpion venom-derived proteins: applications in cancer therapy

Despite breakthroughs in the development of cancer diagnosis and therapy, most current therapeutic approaches lack precise specificity and sensitivity, resulting in damage to healthy cells. Selective delivery of anti-cancer agents is thus an important goal of cancer therapy. Scorpion venom (SV) and/or body parts have been used since early civilizations for medicinal purposes, and in cultures, SV is still applied to the treatment of several diseases including cancer. SV contains numerous active micro and macromolecules with diverse pharmacological effects. These include potent anti-microbial, anti-viral, anti-inflammatory, and anti-cancer properties. This review focuses on the recent advances of SV-derived peptides as promising anti-cancer agents and their diagnostic and therapeutic potential applications in cancers such as glioma, breast cancer, prostate cancer, and colon cancer. Well-characterized SV-derived peptides are thus needed to serve as potent and selective adjuvant therapy for cancer, to significantly enhance the patients' survival and wellbeing.

Venom-derived peptides for breaking through the glass ceiling of drug development

Venoms are complex mixtures produced by animals and consist of hundreds of components including small molecules, peptides, and enzymes selected for effectiveness and efficacy over millions of years of evolution. With the development of venomics, which combines genomics, transcriptomics, and proteomics to study animal venoms and their effects deeply, researchers have identified molecules that selectively and effectively act against membrane targets, such as ion channels and G protein-coupled receptors. Due to their remarkable physico-chemical properties, these molecules represent a credible source of new lead compounds. Today, not less than 11 approved venom-derived drugs are on the market. In this review, we aimed to highlight the advances in the use of venom peptides in the treatment of diseases such as neurological disorders, cardiovascular diseases, or cancer. We report on the origin and activity of the peptides already approved and provide a comprehensive overview of those still in development.

Unveiling Tst3, a Multi-Target Gating Modifier Scorpion α Toxin from Tityus stigmurus Venom of Northeast Brazil: Evaluation and Comparison with Well-Studied Ts3 Toxin of Tityus serrulatus

Studies on the interaction sites of peptide toxins and ion channels typically involve site-directed mutations in toxins. However, natural mutant toxins exist among them, offering insights into how the evolutionary process has conserved crucial sequences for activities and molecular target selection. In this study, we present a comparative investigation using electrophysiological approaches and computational analysis between two alpha toxins from evolutionarily close scorpion species of the genus Tityus, namely, Tst3 and Ts3 from T. stigmurus and T. serrulatus, respectively. These toxins exhibit three natural substitutions near the C-terminal region, which is directly involved in the interaction between alpha toxins and Nav channels. Additionally, we characterized the activity of the Tst3 toxin on Nav1.1-Nav1.7 channels. The three natural changes between the toxins did not alter sensitivity to Nav1.4, maintaining similar intensities regarding their ability to alter opening probabilities, delay fast inactivation, and induce persistent currents. Computational analysis demonstrated a preference for the down conformation of VSD4 and a shift in the conformational equilibrium towards this state. This illustrates that the sequence of these toxins retained the necessary information, even with alterations in the interaction site region. Through electrophysiological and computational analyses, screening of the Tst3 toxin on sodium isoform revealed its classification as a classic α-NaTx with a broad spectrum of activity. It effectively delays fast inactivation across all tested isoforms. Structural analysis of molecular energetics at the interface of the VSD4-Tst3 complex further confirmed this effect.

Chemical synthesis and functional characterization of LaIT3, an insecticidal two-domain peptide in Liocheles australasiae venom

LaIT3, belonging to the β-KTx family, is an insecticidal peptide in the venom of the Liocheles australasiae scorpion. Peptides in the family consist of two structural domains: an N-terminal domain with an α-helical structure common to antimicrobial peptides and a C-terminal domain with a structure stabilized by three disulfide bonds common to ion-channel blocking peptides. However, the contribution of each domain of LaIT3 to its activity remained unknown. In addition, some peptidic components are known to be enzymatically cleaved in the venom, which generates partial peptides. In our study, we searched for partial peptides of LaIT3 using LC/MS analysis and found peptides generated by cleavage at the central region of LaIT3. We subsequently synthesized full-length LaIT3 and its partial peptides to evaluate their insecticidal activity. The results, showing that only full-length LaIT3 is active, indicate that the insecticidal activity of LaIT3 depends on the presence of both N-terminal and C-terminal domains. Furthermore, LaIT3 did not exhibit the cytolytic activity against insect cells and showed only weak antibacterial activity. These findings suggest that its action is not due to a simple membrane disruption effect but instead due to actions on specific target molecules, including ion channels.

Scorpion Venom as a Source of Antimicrobial Peptides: Overview of Biomolecule Separation, Analysis and Characterization Methods

Scorpion venoms have long captivated scientific researchers, primarily due to the potency and specificity of the mechanism of action of their derived components. Among other molecules, these venoms contain highly active compounds, including antimicrobial peptides (AMPs) and ion channel-specific components that selectively target biological receptors with remarkable affinity. Some of these receptors have emerged as prime therapeutic targets for addressing various human pathologies, including cancer and infectious diseases, and have served as models for designing novel drugs. Consequently, extensive biochemical and proteomic investigations have focused on characterizing scorpion venoms. This review provides a comprehensive overview of the key methodologies used in the extraction, purification, analysis, and characterization of AMPs and other bioactive molecules present in scorpion venoms. Noteworthy techniques such as gel electrophoresis, reverse-phase high-performance liquid chromatography, size exclusion chromatography, and "omics" approaches are explored, along with various combinations of methods that enable bioassay-guided venom fractionation. Furthermore, this review presents four adapted proteomic workflows that lead to the comprehensive dissection of the scorpion venom proteome, with an emphasis on AMPs. These workflows differ based on whether the venom is pre-fractionated using separation techniques or is proteolytically digested directly before further proteomic analyses. Since the composition and functionality of scorpion venoms are species-specific, the selection and sequence of the techniques for venom analyses, including these workflows, should be tailored to the specific parameters of the study.

Unveiling the Protein Components of the Secretory-Venom Gland and Venom of the Scorpion Centruroides possanii (Buthidae) through Omic Technologies

Centruroides possanii is a recently discovered species of "striped scorpion" found in Mexico. Certain species of Centruroides are known to be toxic to mammals, leading to numerous cases of human intoxications in the country. Venom components are thought to possess therapeutic potential and/or biotechnological applications. Hence, obtaining and analyzing the secretory gland transcriptome and venom proteome of C. possanii is relevant, and that is what is described in this communication. Since this is a newly described species, first, its LD50 to mice was determined and estimated to be 659 ng/g mouse weight. Using RNA extracted from this species and preparing their corresponding cDNA fragments, a transcriptome analysis was obtained on a Genome Analyzer (Illumina) using the 76-base pair-end sequencing protocol. Via high-throughput sequencing, 19,158,736 reads were obtained and ensembled in 835,204 sequences. Of them, 28,399 transcripts were annotated with Pfam. A total of 244 complete transcripts were identified in the transcriptome of C. possanii. Of these, 109 sequences showed identity to toxins that act on ion channels, 47 enzymes, 17 protease inhibitors (PINs), 11 defense peptides (HDPs), and 60 in other components. In addition, a sample of the soluble venom obtained from this scorpion was analyzed using an Orbitrap Velos apparatus, which allowed for identification by liquid chromatography followed by mass spectrometry (LC-MS/MS) of 70 peptides and proteins: 23 toxins, 27 enzymes, 6 PINs, 3 HDPs, and 11 other components. Until now, this work has the highest number of scorpion venom components identified through omics technologies. The main novel findings described here were analyzed in comparison with the known data from the literature, and this process permitted some new insights in this field.