Dados do Trabalho

Título

Bioconjugation of peptides and guanidines as a strategy to develop New antileishmanial compounds

Introdução

INTRODUCION: Leishmaniasis are a group of diseases caused by different species of the parasite Leishmania spp. This disease is classified as a neglected parasitic disease, as it has few therapeutic options for its control, which present problems such as high toxicity, low efficacy, parenteral administration and long treatment periods. For this reason, it is necessary to search for new treatment strategies that are specific, being able to act on enzymes important for the virulence and survival of the parasite, such as cysteine protease, which is highly expressed in the amastigote form. In this context, antimicrobial peptides and their bioconjugates are alternatives that may allow the development of new, more active therapies against leishmaniasis. The TAT was chosen because it is a cell-penetrating peptide (CPP)  was bioconjugated due to the fact that it facilitates the entry of guanidine into the Leishmania cell.  

Objetivo (s)

The main focus of this work  is to develop a molecule with leishmanicidal activity and high selectivity and that inhibits the Leishmania cysteine ​​protease enzyme.

Material e Métodos

The bioconjugates were synthesized using the solid phase peptide synthesis methodology, from which they were purified by high performance chromatography (HPLC) and the molecular mass confirmed by mass spectrometry. Biological activity was evaluated in murine peritoneal macrophages and in the promastigotes and amastigotes forms of Leishmania amazonensis, in addition, the mechanism of action of these molecules was evaluated with unilamellar vesicle membrane mimetic studies and CPB enzymatic inhibition studies.

Resultados e Conclusão

The TAT peptide and the GVL-TAT bioconjugate have a purity greater than 95%. Only the GVL1-TAT bioconjugate showed leishmanicidal activity, with IC50 in amastigote of 0.80 uM and a selectivity index greater than 1250. Furthermore, vesicle permeabilization data demonstrated that the molecule has no action on the membrane and that the probable mechanism of action of these molecules is the inhibition of the CPB enzyme, with an inhibition of 92% at a concentration of 20 uM. The GVL-1 TAT peptide presented very interesting inhibition values for the cysteine protease enzyme, as well as demonstrating leishmanial activity against the amastigote form, using peritoneal macrophages from murine and excellent selectivity index. Therefore, this molecule is promising for continued studies.  

Palavras Chave

Bioconjugation; Leishmaniasis; drug discovery