Identification of Plasmodium dipeptidyl aminopeptidase allosteric inhibitors by high throughput screening

• Published in: PloS one Vol. 14; no. 12; p. e0226270
• Main Authors: Sanchez, Mateo I, de Vries, Laura E, Lehmann, Christine, Lee, Jeong T, Ang, Kenny K, Wilson, Christopher, Chen, Steven, Arkin, Michelle R, Bogyo, Matthew, Deu, Edgar
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 18.12.2019; Public Library of Science (PLoS)
• Subjects: Allosteric properties; Aminopeptidase; Aminopeptidases; Antimalarial agents; Antimalarials - pharmacology; Antimalarials - toxicity; Artemisinin; Asexuality; Biology; Biology and Life Sciences; Blood; Cathepsins; Cells, Cultured; Chemistry; Clinical trials; Crick, Francis; Cysteine; Cysteine Proteases; Cysteine Proteinase Inhibitors - pharmacology; Cystine; Departments; Developmental stages; Dipeptidyl-peptidase I; Dipeptidyl-Peptidases and Tripeptidyl-Peptidases - antagonists & inhibitors; Drug development; Drug Evaluation, Preclinical; Enzymes; Hemoglobin; High-throughput screening; Homology; Humans; Immunology; Inflammatory diseases; Inhibitors; Malaria; Medicine; Medicine and Health Sciences; N-Terminus; Parasites; Parasitic diseases; Pathology; Peptides; Plasmodium; Plasmodium falciparum; Plasmodium falciparum - drug effects; Plasmodium falciparum - enzymology; Proteases; Protozoan Proteins - antagonists & inhibitors; Screening; Substrates; Toxoplasmosis; Vector-borne diseases; San Francisco California; California; United Kingdom > UK; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0226270

Dipeptidyl aminopeptidases (DPAPs) are cysteine proteases that cleave dipeptides from the N-terminus of protein substrates and have been shown to play important roles in many pathologies including parasitic diseases such as malaria, toxoplasmosis and Chagas's disease. Inhibitors of the mammalian homologue cathepsin C have been used in clinical trials as potential drugs to treat chronic inflammatory disorders, thus proving that these enzymes are druggable. In Plasmodium species, DPAPs play important functions at different stages of parasite development, thus making them potential antimalarial targets. Most DPAP inhibitors developed to date are peptide-based or peptidomimetic competitive inhibitors. Here, we used a high throughput screening approach to identify novel inhibitor scaffolds that block the activity of Plasmodium falciparum DPAP1. Most of the hits identified in this screen also inhibit Plasmodium falciparum DPAP3, cathepsin C, and to a lesser extent other malarial clan CA proteases, indicating that these might be general DPAP inhibitors. Interestingly, our mechanism of inhibition studies indicate that most hits are allosteric inhibitors, which opens a completely new strategy to inhibit these enzymes, study their biological function, and potentially develop new inhibitors as starting points for drug development.