ABSTRACT
Leishmaniases are an ensemble of diseases caused by the protozoan parasite of the genus Leishmania. Current antileishmanial treatments are limited and present main issues of toxicity and drug resistance emergence. Therefore, the generation of new inhibitors specifically directed against a leishmanial target is an attractive strategy to expand the chemotherapeutic arsenal. GDP-Mannose Pyrophosphorylase (GDP-MP) is a prominent therapeutic target involved in host-parasite recognition which has been described to be essential for parasite survival. In this work, we produced and purified GDP-MPs from L. mexicana (LmGDP-MP), L. donovani (LdGDP-MP), and human (hGDP-MP), and compared their enzymatic properties. From a rationale design of 100 potential inhibitors, four compounds were identified having a promising and specific inhibitory effect on parasite GDP-MP and antileishmanial activities, one of them exhibits a competitive inhibition on LdGDP-MP and belongs to the 2-substituted quinoline series.
Subject(s)
Antiprotozoal Agents/pharmacology , Drug Discovery , Enzyme Inhibitors/pharmacology , Leishmania/drug effects , Leishmania/metabolism , Nucleotidyltransferases/antagonists & inhibitors , Animals , Antiprotozoal Agents/chemistry , Catalytic Domain , Enzyme Activation/drug effects , Enzyme Inhibitors/chemistry , Humans , Mice , Molecular Conformation , Molecular Docking Simulation , Molecular Dynamics Simulation , Nucleotidyltransferases/chemistry , Nucleotidyltransferases/isolation & purification , Nucleotidyltransferases/metabolism , Protein Binding , RAW 264.7 Cells , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , Structure-Activity RelationshipABSTRACT
A series of non-hydrolysable 5'-aryl substituted GDP analogs has been synthesized by reacting 5'-azido-5'-deoxyguanosine with different aryl- and benzyloxy-alkynes. Cu(I) nanoparticles in water were found to be the most efficient catalyst, producing the desired 5'-arylguanosines with good yields. The synthesized compounds were screened for in vitro antileishmanial activity against Leishmania donovani axenic amastigotes and intramacrophage amastigotes stages. The 4-(3-nitrobenzyl)-1,2,3-triazole 5'-substituted guanosine analog was found to be the most active in the series with an IC50 of 8.6 µM on axenic amastigotes. Despite a rather low in vitro antileishmanial activity on the intramacrophage amastigotes, the absence of cytotoxicity on RAW 264.7 macrophages justifies further pharmacomodulations making this antileishmanial series promising.
Subject(s)
Alkynes/chemistry , Antiprotozoal Agents/chemical synthesis , Antiprotozoal Agents/pharmacology , Azides/chemistry , Deoxyguanosine/analogs & derivatives , Leishmania donovani/drug effects , Animals , Antiprotozoal Agents/chemistry , Antiprotozoal Agents/metabolism , Click Chemistry , Deoxyguanosine/chemical synthesis , Deoxyguanosine/chemistry , Deoxyguanosine/metabolism , Deoxyguanosine/pharmacology , Leishmania donovani/enzymology , Mannose-6-Phosphate Isomerase/chemistry , Mannose-6-Phosphate Isomerase/metabolism , Mice , Molecular Docking Simulation , Protein ConformationABSTRACT
Leishmania is the parasite responsible for the neglected disease leishmaniasis. Its virulence and survival require biosynthesis of glycoconjugates, whose guanosine diphospho-d-mannose pyrophosphorylase (GDP-MP) is a key player. However, experimentally resolved structures of this enzyme are still lacking. We herein propose structural models of the GDP-MP from human and Leishmania donovani. Based on a multiple sequences alignment, the models were built with MODELLER and then carefully refined with all atom molecular dynamics simulations in explicit solvent. Their quality was evaluated against several standard criteria, including their ability to bind GDP-mannose assessed by redocking calculations. Special attention was given in this study to interactions of the catalytic site residues with the enzyme substrate and competitive inhibitors, opening the perspective of medicinal chemistry developments.
