Disruption of a Plasmodium falciparum Multidrug Resistance-associated Protein (PfMRP) Alters Its Fitness and Transport of Antimalarial Drugs and Glutathione

Abstract

ATP-binding cassette transporters play an important role in drug resistance and nutrient transport. In the human malaria parasite Plasmodium falciparum, a homolog of the human p-glycoprotein (PfPgh-1) was shown to be involved in resistance to several drugs. More recently, many transporters were associated with higher IC 50 levels in responses to chloroquine (CQ) and quinine (QN) in field isolates. Subsequent studies, however, could not confirm the associations, although inaccuracy in drug tests in the later studies could contribute to the lack of associations. Here we disrupted a gene encoding a putative multidrug resistance-associated protein (PfMRP) that was previously shown to be associated with P. falciparum responses to CQ and QN. Parasites with disrupted PfMRP (W2/MRP⌬) could not grow to a parasitemia higher than 5% under normal culture conditions, possibly because of lower efficiency in removing toxic metabolites. The W2/MRP⌬ parasite also accumulated more radioactive glutathione, CQ, and QN and became more sensitive to multiple antimalarial drugs, including CQ, QN, artemisinin, piperaquine, and primaquine. PfMRP was localized on the parasite surface membrane, within membrane-bound vesicles, and along the straight side of the D-shaped stage II gametocytes. The results suggest that PfMRP plays a role in the efflux of glutathione, CQ, and QN and contributes to parasite responses to multiple antimalarial drugs, possibly by pumping drugs outside the parasite.

Whole-genome sequencing and microarray analysis of ex vivo Plasmodium vivax reveal selective pressure on putative drug resistance genes

“…S3). Notably, P. falciparum knockout strains are also more sensitive to primaquine (40). Given the tremendous need for molecular markers that Fig.…”

“…Studies of PfMRP1 have shown that one of its roles is to pump out glutathione (40). The killing effect of primaquine is thought to be through introducing oxidative damage to mitochondria, and thus if parasites showed an improved ability to export glutathione adducts, tolerance might be expected.…”

“…The killing effect of primaquine is thought to be through introducing oxidative damage to mitochondria, and thus if parasites showed an improved ability to export glutathione adducts, tolerance might be expected. In addition, knockouts of the gene in P. falciparum have rendered the parasites more sensitive to primaquine (40). It should be noted, however, that PfMRP1 has also been associated with artemisinin resistance in P. falciparum (53), and, therefore, PvMRP1 may be a general drug resistance protein.…”

“…3E and Table S2). The syntenic P. falciparum gene, also showing the greatest sequence homology, is the multidrug resistance protein 1 (PFA0590w, PfMRP1, BlastP P < 10 −300 ), which has been associated with quinoline resistance (38)(39)(40) and resistance to antifolates (41). Most of the substitutions are in sequences that are conserved across Plasmodium species (Fig.…”

Malaria por Plasmodium vivax y falla al tratamiento radical

“…Este gen podría intervenir en un mecanismo de resistencia a PQ 29 . Estudios in vitro han demostrado que parásitos knock out para pvmrp incrementan significativamente su sensibilidad a diferentes fármacos antimaláricos, incluyendo PQ 30 . Además, se encontró una similitud entre el perfil genómico de estos aislados con la cepa Brazil-I, asociada clínicamente a tolerancia a PQ 31 , y diferencias significativas con la cepa Sal-I, sensible a PQ 25 .…”