RESUMO
Achieving the goal of malaria elimination will depend on targeting Plasmodium pathways essential across all life stages. Here we identify a lipid kinase, phosphatidylinositol-4-OH kinase (PI(4)K), as the target of imidazopyrazines, a new antimalarial compound class that inhibits the intracellular development of multiple Plasmodium species at each stage of infection in the vertebrate host. Imidazopyrazines demonstrate potent preventive, therapeutic, and transmission-blocking activity in rodent malaria models, are active against blood-stage field isolates of the major human pathogens P. falciparum and P. vivax, and inhibit liver-stage hypnozoites in the simian parasite P. cynomolgi. We show that imidazopyrazines exert their effect through inhibitory interaction with the ATP-binding pocket of PI(4)K, altering the intracellular distribution of phosphatidylinositol-4-phosphate. Collectively, our data define PI(4)K as a key Plasmodium vulnerability, opening up new avenues of target-based discovery to identify drugs with an ideal activity profile for the prevention, treatment and elimination of malaria.
Assuntos
1-Fosfatidilinositol 4-Quinase/antagonistas & inibidores , Malária/tratamento farmacológico , Malária/parasitologia , Plasmodium/efeitos dos fármacos , Plasmodium/enzimologia , 1-Fosfatidilinositol 4-Quinase/química , 1-Fosfatidilinositol 4-Quinase/genética , 1-Fosfatidilinositol 4-Quinase/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Sítios de Ligação , Citocinese/efeitos dos fármacos , Resistência a Medicamentos/efeitos dos fármacos , Resistência a Medicamentos/genética , Ácidos Graxos/metabolismo , Feminino , Hepatócitos/parasitologia , Humanos , Imidazóis/metabolismo , Imidazóis/farmacologia , Estágios do Ciclo de Vida/efeitos dos fármacos , Macaca mulatta , Masculino , Modelos Biológicos , Modelos Moleculares , Fosfatos de Fosfatidilinositol/metabolismo , Plasmodium/classificação , Plasmodium/crescimento & desenvolvimento , Pirazóis/metabolismo , Pirazóis/farmacologia , Quinoxalinas/metabolismo , Quinoxalinas/farmacologia , Reprodutibilidade dos Testes , Esquizontes/citologia , Esquizontes/efeitos dos fármacos , Proteínas rab de Ligação ao GTP/genética , Proteínas rab de Ligação ao GTP/metabolismoRESUMO
With renewed calls for malaria eradication, next-generation antimalarials need be active against drug-resistant parasites and efficacious against both liver- and blood-stage infections. We screened a natural product library to identify inhibitors of Plasmodium falciparum blood- and liver-stage proliferation. Cladosporin, a fungal secondary metabolite whose target and mechanism of action are not known for any species, was identified as having potent, nanomolar, antiparasitic activity against both blood and liver stages. Using postgenomic methods, including a yeast deletion strains collection, we show that cladosporin specifically inhibits protein synthesis by directly targeting P. falciparum cytosolic lysyl-tRNA synthetase. Further, cladosporin is >100-fold more potent against parasite lysyl-tRNA synthetase relative to the human enzyme, which is conferred by the identity of two amino acids within the enzyme active site. Our data indicate that lysyl-tRNA synthetase is an attractive, druggable, antimalarial target that can be selectively inhibited.