Identification by high-throughput screening of inhibitors of Schistosoma mansoni NAD(+) catabolizing enzyme.
Schistosomiasis is a major tropical parasitic disease. For its treatment, praziquantel remains the only effective drug available and the dependence on this sole chemotherapy emphasizes the urgent need for new drugs to control this neglected disease. In this context, the newly characterized Schistosoma mansoni NAD(+) catabolizing enzyme (SmNACE) represents a potentially attractive drug target. This potent NAD(+)glycohydrolase, which is localized to the outer surface (tegument) of the adult parasite, is presumably involved in the parasite survival by manipulating the host's immune regulatory pathways. In an effort to identify SmNACE inhibitors, we have developed a sensitive and robust fluorometric high-throughput screening assay. The implementation of this assay to the screening of a highly diverse academic chemical library of 14,300 molecules yielded, after secondary assays and generation of dose-response curves, the identification of two natural product inhibitors, cyanidin and delphinidin. These confirmed hits inhibit SmNACE with IC(50) values in the low micromolar range. To rationalize the structure-activity relationship, several related flavonoids were tested, thereby leading to the identification of 15 additional natural product inhibitors. A selection of representative flavonoid inhibitors indicated that although they also inhibit the homologous human CD38, a selectivity in favor of SmNACE could be reached. Docking studies indicated that these inhibitors mimic the binding mode of the enzyme substrate NAD(+) and suggested the pharmacophoric features required for SmNACE active site recognition.
Laboratoire de Conception et Application de Molécules Bioactives, UMR 7199 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67400 Illkirch, France.
Isabelle
I
Kuhn
Esther
E
Kellenberger
Fatouma
F
Said-Hassane
Pascal
P
Villa
Didier
D
Rognan
Annelise
A
Lobstein
Jacques
J
Haiech
Marcel
M
Hibert
Francis
F
Schuber
Hélène
H
Muller-Steffner
D051997:ADP-ribosyl Cyclase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D020134:Catalytic Domain; D003198:Computer Simulation; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D005419:Flavonoids / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D057166:High-Throughput Screening Assays; D006801:Humans; D009244:NAD+ Nucleosidase / Q000737:chemistry* / Q000378:metabolism; D012550:Schistosoma mansoni / Q000201:enzymology*; D012556:Schistosomicides / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D013329:Structure-Activity Relationship
D004791:Enzyme Inhibitors; D005419:Flavonoids; D012556:Schistosomicides; D009244:NAD+ Nucleosidase; D051997:ADP-ribosyl Cyclase 1