Abstract
Trypanothione reductase (TR) is considered to be one of the best targets to find new drugs against Leishmaniasis. This enzyme is fundamental for parasite survival in the host since it reduces trypanothione, a molecule used by the tryparedoxin/tryparedoxin peroxidase system of Leishmania to neutralize hydrogen peroxide produced by host macrophages during infection. In order to identify new lead compounds against Leishmania we developed and validated a new luminescence-based high-throughput screening (HTS) assay that allowed us to screen a library of 120,000 compounds. We identified a novel chemical class of TR inhibitors, able to kill parasites with an IC50 in the low micromolar range. The X-ray crystal structure of TR in complex with a compound from this class (compound 3) allowed the identification of its binding site in a pocket at the entrance of the NADPH binding site. Since the binding site of compound 3 identified by the X-ray structure is unique, and is not present in human homologs such as glutathione reductase (hGR), it represents a new target for drug discovery efforts.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Antiprotozoal Agents / chemistry*
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Antiprotozoal Agents / metabolism
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Antiprotozoal Agents / pharmacology
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Binding Sites
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Crystallography, X-Ray
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Drug Evaluation, Preclinical
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Enzyme Inhibitors / chemistry*
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Enzyme Inhibitors / metabolism
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Enzyme Inhibitors / pharmacology
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High-Throughput Screening Assays
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Humans
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Leishmania / drug effects
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Leishmania / enzymology*
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Leishmania / genetics
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Leishmaniasis / parasitology
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Models, Molecular
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NADH, NADPH Oxidoreductases / antagonists & inhibitors*
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NADH, NADPH Oxidoreductases / chemistry
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NADH, NADPH Oxidoreductases / genetics
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NADH, NADPH Oxidoreductases / metabolism
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NADP / metabolism
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Protozoan Proteins / antagonists & inhibitors*
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Protozoan Proteins / chemistry
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Protozoan Proteins / genetics
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Protozoan Proteins / metabolism
Substances
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Antiprotozoal Agents
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Enzyme Inhibitors
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Protozoan Proteins
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NADP
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NADH, NADPH Oxidoreductases
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trypanothione reductase
Grants and funding
This work is founded by CNCCS s.c.a.r.l. (National Collection of Chemical Compounds and Screening Center 2015) and by MIUR PRIN 20154JRJPP. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.