Quantum Biochemistry Screening and In Vitro Evaluation of Leishmania Metalloproteinase Inhibitors

Special Issue Molecular Research on Vector-Borne Diseases of Medical Interest: From Bench to Application 2.0 Funding Information: Global Health and Tropical Medicine funded this research: Grant number IHMT-UID/multi/04413/2013 and Grant number PTDC/CVT-CVT/28908/2017, FCT-Portugal. Funding Information: We would like to thank to CNPq/Brazil, CAPES/Brazil and FCT/Portugal for grants and fellowships. C.J.G.M., J.W.d.F.O., T.K.d.B.P., F.L.d.S.J. and B.A.-C. thank the financial support (PhD and Post-doctoral fellowships) provided by Capes/Brazil. M.S.S. and H.A.O.R. thank CNPq/Brazil for the Research Grant (Bolsa de Produtividade em Pesquisa). We also would like to thank the Department of Materials Engineering at UFRN for allowing the use of their scanning electron microscope, and the Department of Biochemistry at UFRN for allowing the use of their flow cytometer. Publisher Copyright: © 2022 by the authors.Leishmanolysin, also known as major promastigote protease (PSP) or gp63, is the most abundant surface glycoprotein of Leishmania spp., and has been extensively studied and recognized as the main parasite virulence factor. Characterized as a metalloprotease, gp63 can be powerfully inactivated in the presence of a metal chelator. In this study, we first used the structural parameters of a 7-hydroxycoumarin derivative, L1 compound, to evaluate the theoretical–computational experiments against gp63, comparing it with an available metal chelator already described. The methodology followed was (i) analysis of the three-dimensional structure of gp63 as well as its active site, and searching the literature and molecular databases for possible inhibitors; (ii) molecular docking simulations and investigation of the interactions in the generated protein–ligand complexes; and (iii) the individual energy of the gp63 amino acids that interacted most with the ligands of interest was quantified by ab initio calculations using Molecular Fraction with Conjugated Caps (MFCC). MFCC still allowed the final quantum balance calculations of the protein interaction to be obtained with each inhibitor candidate binder. L1 obtained the best energy quantum balance result with −2 eV, followed by DETC (−1.4 eV), doxycycline (−1.3 eV), and 4-terpineol (−0.6 eV), and showed evidence of covalent binding in the enzyme active site. In vitro experiments confirmed L1 as highly effective against L. amazonensis parasites. The compound also exhibited a low cytotoxicity profile against mammalian RAW and 3T3 cells lines, presenting a selective index of 149.19 and 380.64 µM, respectively. L1 induced promastigote forms’ death by necrosis and the ultrastructural analysis revealed disruption in membrane integrity. Furthermore, leakage of the contents and destruction of the parasite were confirmed by Spectroscopy Dispersion analysis. These results together suggested L1 has a potential effect against L. amazonensis, the etiologic agent of diffuse leishmaniasis, and the only one that currently does not have a satisfactory treatment.publishersversionpublishe