Estudo in vitro da atividade tripanocida da crotalicidina - catelicidina da glândula do veneno de Crotalus durissus terrificus

Abstract

Cathelicidins are antimicrobial peptides produced by humans and animals in response to various pathogenic microbes. Crotalicidin (Ctn), a cathelicidin-related vipericidin from the South American rattlesnake Crotalus durissus terrificus venom gland, and its fragments have demonstrated antimicrobial and antifungal activity, likewise human cathelicidin LL-37. In order to provide templates for the development of modern trypanocidal agents, in the present study we evaluated the antichagasic effect of these four peptides (Ctn, Ctn[1-14], Ctn[15-34] and LL-37). Herein, Ctn and short derived peptides were tested against epimastigote, trypomastigote and amastigote forms of T. cruzi Y strain (benznidazole-resistant strain) and cytotoxicity on mammalian cells were evaluated toward LLC-MK2 lineage. Ctn inhibited all T. cruzi developmental forms, including amastigotes, which is implicated in the burden of infection in the chronic phase of Chagas’ disease. Moreover, Ctn showed a high selective index to trypomastigote forms (> 200). Ctn induced cell death in T. cruzi through necrosis, as determined by flow cytometry analyses with specific molecular probes and morphological alterations, such as loss of membrane integrity and cell shrinkage, as observed by scanning electron microscopy (SEM). In the in vivo test, an acute toxicity assessment by the Up-and-Down method showed that Ctn did not promote hematological, biochemical and did not cause damage to animal organs.Altogether, Ctn appears as a promising template for the development of antichagasic agents.