Avaliação estrutural e atividades antiproliferativa, antiviral, antiparasitária e antibacteriana dos peptídeos Stigmurina e TsAP-2 presentes na peçonha do escorpião Tityus stigmurus

Abstract

The resistance to conventional drugs in diseases of infectious and neoplasic origin is a serious public health problem worldwide, presenting high morbidity and mortality, leading to an incessant search for new therapeutic agents in different natural sources. In this context, the scorpion venom constitutes a rich arsenal of bioactive molecules, being non disulphide-bridged peptides (NDBPs) target of studies due to its multifunctional actions. Stigmurin (FFSLIPSLVGGLISAFK-NH2, 1795.2 Da) and TsAP-2 (FLGMIPGLIGGLISAFK-NH2, 1733.2 Da) are NDBPs identified on the venom gland transcriptome of the Tityus stigmurus. Considering the multifunctional action of NDBPS, in this study the three-dimensional structure of the Stigmurin was elucidated by nuclear magnetic resonance and the antiproliferative, immunomodulatory, antiparasitic, antiviral, antioxidant and antibiofilm activity of the synthetic peptides Stigmurin and TsAP-2 were evaluated. The healing and antibiotic effects of both peptides were evaluated by bacterial wound infection model in vivo, as well as expanding the in vitro antibacterial potential of the TsAP-2. Stigmurin in trifluoroethanol: water (40:60%) showed a random conformation in the N-terminal region, with a helical structure from the seventh amino acid residue, being the first NDBP present in the venom of scorpions of the genus Tityus with an elucidated three-dimensional structure. Stigmurin and TsAP-2 revealed antiproliferative action on neoplastic cells in non-toxic concentration for normal cells, modulating the release of nitrite in murine macrophages stimulated by lipopolysaccharides. Stigmurin and TsAP-2 did not demonstrate a leishmanicidal effect on the amastigote form of Leishmania braziliensis. However, TsAP-2 revealed a high trypanocidal action of on epimastigote and trypomastigote forms of Trypanosoma cruzi, and broad spectrum of antibacterial action against Gram-positive and Gram-negative microorganisms. A protective effect on primate renal epithelial cells against Zika virus infection was demonstrated in the pretreatment assay for both peptides, revealing a high virucidal action on herpes simplex virus type 1, with antiviral activity in post-infection assay. In addition, Stigmurin and TsAP-2 were able to scavenge the hydroxyl radical in vitro at concentration of 10 µM and 5 µM, respectivety, reducing its action in high concentrations, suggesting the formation of agglomerates. Both peptides showed antibiofilm activity, as well as antibacterial action in the skin wound infection model, increasing the retraction rate of the lesion, suggesting the ability to induce tissue repair. In histopathological analysis, TsAP-2 promoted increased neovascularization and re-epithelization, reducing necrosis in the surgical wound.The data suggest that Stigmurin and TsAP-2 are promising multifunctional peptides for use as prototype to obtaining new therapeutic agents.