Anti-Trypanosoma cruzi activity of non-peptidic agentes as inhibitors of the cysteine protease cruzain

Author(s)

Rafael da Fonseca Lameiro

• Document type: Master's Dissertation
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Instituto de Química de São Carlos (IQSC/BT)
• Defense date: 2020-03-13

Examining board members

Carlos Alberto Montanari; Ricardo Samuel Schwab

• Advisor: Carlos Alberto Montanari

Abstract

Chagas disease, caused by the protozoan Trypanosoma cruzi, was first described in 1909 by the Brazilian physician Carlos Chagas. Despite being known for over a hundred years, treatments for this disease are currently limited to only two drugs that, besides generating side effects, are not capable of eliminating the parasites from the host body in the chronic phase of the disease. In the context of developing new drugs for Chagas disease, the cysteine protease cruzain stands out as a molecular target for inhibition, due to its essential role in the life cycle of the trypanosome. In this work, compounds derived from Neq0594, a trypanocidal agent and cruzain inhibitor previously developed in NEQUIMED/IQSC/USP, were produced. These derivatives have their structures based on dipeptides, which are the natural substrate of cruzain, but, because they have a 2,2,2-trifluoroethylamine group replacing a peptide bond, and fluorine atoms substituting hydrogen atoms, they must be more bioavailable and metabolically stable than their peptide analogues. Fifteen derivatives of Neq0594 were synthesized, purified and characterized (1H-NMR, 13C-NMR, FTIR, HRMS, polarimetry and melting point) for the structure-activity relationship study. The compounds were tested for cruzain, LmCPB and cathepsin L and displayed activities equal to or better than the lead compound for cruzain. It was also observed the preference of this enzyme for compounds with the isobutyl group at P2 and with (S,S) stereochemistry, as well as the bioisosterism of the H/F replacement. The results also suggest the presence of crossed structure-activity relationships between the protozoan cysteine proteases (cruzain and LmCPB). Moreover, computer simulations using the molecular dynamics method were performed to explore the interactions of three compounds with cruzain. The simulations demonstrated the major hydrogen bonds with the residues Gly66 and Asp161, hydrophobic interactions at P2 and P3 and the absence of polar interactions with the P3 fluorine atoms. (AU)

• FAPESP's process: 18/03279-0 - Anti-Trypanosoma cruzi activity of non-Peptidic agents as inhibitors of cysteine protease cruzain
• Grantee: Rafael da Fonseca Lameiro
• Support Opportunities: Scholarships in Brazil - Master