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A molecular mechanism of artemisinin resistance in Plasmodium falciparum malaria

2015; Nature Portfolio; Volume: 520; Issue: 7549 Linguagem: Inglês

10.1038/nature14412

1476-4687

Alassane Mbengue, Souvik Bhattacharjee, Trupti Pandharkar, Haining Liu, Guillermina Estiú, Robert V. Stahelin, Shahir S. Rizk, Dieudonné Lemuh Njimoh, Yana Ryan, Kesinee Chotivanich, Chea Nguon, Mehdi Ghorbal, José-Juan Lopez-Rubio, Michael E. Pfrender, Scott Emrich, Narla Mohandas, Arjen M. Dondorp, Olaf Wiest, Kasturi Haldar,

Computational Drug Discovery Methods

Artemisinins are key anti-malarial drugs, but artemisinin resistance has been increasing; this study identifies the molecular target of artemisinins as phosphatidylinositol-3-kinase and increase of the lipid product phosphatidylinositol-3-phosphate induces resistance in Plasmodium falciparum. The emergence of artemisinin resistance is a major threat to world-wide malaria treatment and control and although artemisinins have been linked with a variety of cellular factors, there has been no consensus on the relevant biochemical targets or mechanisms underpinning resistance. Here Kasturi Haldar and colleagues show that artemisinins target the parasite phosphatidylinositol-3-kinase (PfPI3K) to inhibit the production of phosphatidylinositol 3-phosphate (PI3P). Mutation in PfKelch13, a previously identified resistance marker, increases levels of PfPI3K in both clinically derived strains and in engineered laboratory parasites. This work points to PfPI3K as the key mediator of artemisinin resistance and a target for malaria elimination. Artemisinins are the cornerstone of anti-malarial drugs1. Emergence and spread of resistance to them2,3,4 raises risk of wiping out recent gains achieved in reducing worldwide malaria burden and threatens future malaria control and elimination on a global level. Genome-wide association studies (GWAS) have revealed parasite genetic loci associated with artemisinin resistance5,6,7,8,9,10. However, there is no consensus on biochemical targets of artemisinin. Whether and how these targets interact with genes identified by GWAS, remains unknown. Here we provide biochemical and cellular evidence that artemisinins are potent inhibitors of Plasmodium falciparum phosphatidylinositol-3-kinase (PfPI3K), revealing an unexpected mechanism of action. In resistant clinical strains, increased PfPI3K was associated with the C580Y mutation in P. falciparum Kelch13 (PfKelch13), a primary marker of artemisinin resistance. Polyubiquitination of PfPI3K and its binding to PfKelch13 were reduced by the PfKelch13 mutation, which limited proteolysis of PfPI3K and thus increased levels of the kinase, as well as its lipid product phosphatidylinositol-3-phosphate (PI3P). We find PI3P levels to be predictive of artemisinin resistance in both clinical and engineered laboratory parasites as well as across non-isogenic strains. Elevated PI3P induced artemisinin resistance in absence of PfKelch13 mutations, but remained responsive to regulation by PfKelch13. Evidence is presented for PI3P-dependent signalling in which transgenic expression of an additional kinase confers resistance. Together these data present PI3P as the key mediator of artemisinin resistance and the sole PfPI3K as an important target for malaria elimination.