title: Artesunate tolerance in transgenic Plasmodium falciparum parasites overexpressing a tryptophan-rich protein.
abstract: Due to their rapid, potent action on young and mature intraerythrocytic stages, artemisinin derivatives are central to drug combination therapies for Plasmodium falciparum malaria. However, the evidence for emerging parasite resistance/tolerance to artemisinins in southeast Asia is of great concern. A better understanding of artemisinin-related drug activity and resistance mechanisms is urgently needed. A recent transcriptome study of parasites exposed to artesunate led us to identify a series of genes with modified levels of expression in the presence of the drug. The gene presenting the largest mRNA level increase, Pf10_0026 (PArt), encoding a hypothetical protein of unknown function, was chosen for further study. Immunodetection with PArt-specific sera showed that artesunate induced a dose-dependent increase of the protein level. Bioinformatic analysis showed that PArt belongs to a Plasmodium-specific gene family characterized by the presence of a tryptophan-rich domain with a novel hidden Markov model (HMM) profile. Gene disruption could not be achieved, suggesting an essential function. Transgenic parasites overexpressing PArt protein were generated and exhibited tolerance to a spike exposure to high doses of artesunate, with increased survival and reduced growth retardation compared to that of wild-type-treated controls. These data indicate the involvement of PArt in parasite defense mechanisms against artesunate. This is the first report of genetically manipulated parasites displaying a stable and reproducible decreased susceptibility to artesunate, providing new possibilities to investigate the parasite response to artemisinins.
authors.affiliation: Institut Pasteur, Unité d'Immunologie Moléculaire des Parasites, Département de Parasitologie Mycologie, CNRS, URA2581, F-75015 Paris, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Deplaine
authors.forename: Catherine
authors.initials: C
authors.lastname: Lavazec
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Bischoff
authors.forename: Onguma
authors.initials: O
authors.lastname: Natalang
authors.forename: Sylvie
authors.initials: S
authors.lastname: Perrot
authors.forename: Micheline
authors.initials: M
authors.lastname: Guillotte-Blisnick
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Coppée
authors.forename: Bruno
authors.initials: B
authors.lastname: Pradines
authors.forename: Odile
authors.initials: O
authors.lastname: Mercereau-Puijalon
authors.forename: Peter H
authors.initials: PH
authors.lastname: David
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000962:Antimalarials / Q000494:pharmacology*; D037621:Artemisinins / Q000494:pharmacology*; D000077332:Artesunate; D004361:Drug Tolerance; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: D000962:Antimalarials; D037621:Artemisinins; D015800:Protozoan Proteins; D000077332:Artesunate