title: Discovery of compounds blocking the proliferation of Toxoplasma gondii and Plasmodium falciparum in a chemical space based on piperidinyl-benzimidazolone analogs.
abstract: A piperidinyl-benzimidazolone scaffold has been found in the structure of different inhibitors of membrane glycerolipid metabolism, acting on enzymes manipulating diacylglycerol and phosphatidic acid. Screening a focus library of piperidinyl-benzimidazolone analogs might therefore identify compounds acting against infectious parasites. We first evaluated the in vitro effects of (S)-2-(dibenzylamino)-3-phenylpropyl 4-(1,2-dihydro-2-oxobenzo[d]imidazol-3-yl)piperidine-1-carboxylate (compound 1) on Toxoplasma gondii and Plasmodium falciparum. In T. gondii, motility and apical complex integrity appeared to be unaffected, whereas cell division was inhibited at compound 1 concentrations in the micromolar range. In P. falciparum, the proliferation of erythrocytic stages was inhibited, without any delayed death phenotype. We then explored a library of 250 analogs in two steps. We selected 114 compounds with a 50% inhibitory concentration (IC50) cutoff of 2 μM for at least one species and determined in vitro selectivity indexes (SI) based on toxicity against K-562 human cells. We identified compounds with high gains in the IC50 (in the 100 nM range) and SI (up to 1,000 to 2,000) values. Isobole analyses of two of the most active compounds against P. falciparum indicated that their interactions with artemisinin were additive. Here, we propose the use of structure-activity relationship (SAR) models, which will be useful for designing probes to identify the target compound(s) and optimizations for monotherapy or combined-therapy strategies.
authors.affiliation: Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique, Université Grenoble Alpes, Institut National de la Recherche Agronomique, Unité Mixte de Recherche 5168, Institut de Recherches en Technologies et Sciences pour le Vivant, Grenoble, France.
authors.forename: Nadia
authors.initials: N
authors.lastname: Saïdani
authors.forename: Cyrille Y
authors.initials: CY
authors.lastname: Botté
authors.forename: Michael
authors.initials: M
authors.lastname: Deligny
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Bonneau
authors.forename: Janette
authors.initials: J
authors.lastname: Reader
authors.forename: Ronald
authors.initials: R
authors.lastname: Lasselin
authors.forename: Goulven
authors.initials: G
authors.lastname: Merer
authors.forename: Alisson
authors.initials: A
authors.lastname: Niepceron
authors.forename: Fabien
authors.initials: F
authors.lastname: Brossier
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Cintrat
authors.forename: Bernard
authors.initials: B
authors.lastname: Rousseau
authors.forename: Lyn-Marie
authors.initials: LM
authors.lastname: Birkholtz
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Cesbron-Delauw
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Dubremetz
authors.forename: Corinne
authors.initials: C
authors.lastname: Mercier
authors.forename: Henri
authors.initials: H
authors.lastname: Vial
authors.forename: Roman
authors.initials: R
authors.lastname: Lopez
authors.forename: Eric
authors.initials: E
authors.lastname: Maréchal
mesh_terms: D000981:Antiprotozoal Agents / Q000494:pharmacology; D001562:Benzimidazoles / Q000494:pharmacology*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D008826:Microbial Sensitivity Tests; D010963:Plasmodium falciparum / Q000187:drug effects*; D013329:Structure-Activity Relationship; D014122:Toxoplasma / Q000187:drug effects*
chemical_list: D000981:Antiprotozoal Agents; D001562:Benzimidazoles; C014353:benzimidazolone