RESUMO
Spread of parasite resistance to artemisinin threatens current frontline antimalarial therapies, highlighting the need for new drugs with alternative modes of action. Since only 0.2-1% of asexual parasites differentiate into sexual, transmission-competent forms, targeting this natural bottleneck provides a tangible route to interrupt disease transmission and mitigate resistance selection. Here we present a high-throughput screen of gametogenesis against a ~70,000 compound diversity library, identifying seventeen drug-like molecules that target transmission. Hit molecules possess varied activity profiles including male-specific, dual acting male-female and dual-asexual-sexual, with one promising N-((4-hydroxychroman-4-yl)methyl)-sulphonamide scaffold found to have sub-micromolar activity in vitro and in vivo efficacy. Development of leads with modes of action focussed on the sexual stages of malaria parasite development provide a previously unexplored base from which future therapeutics can be developed, capable of preventing parasite transmission through the population.
Assuntos
Antimaláricos/análise , Avaliação Pré-Clínica de Medicamentos , Ensaios de Triagem em Larga Escala/métodos , Malária/parasitologia , Malária/transmissão , Parasitos/fisiologia , Animais , Antimaláricos/química , Antimaláricos/farmacologia , Comportamento Alimentar , Feminino , Gametogênese/efeitos dos fármacos , Células Hep G2 , Humanos , Masculino , Camundongos , Parasitos/efeitos dos fármacos , Fenótipo , Reprodutibilidade dos Testes , Relação Estrutura-AtividadeRESUMO
Plasmodium falciparum stage V gametocytes are responsible for parasite transmission, and drugs targeting this stage are needed to support malaria elimination. We here screen the Tres Cantos Antimalarial Set (TCAMS) using the previously developed P. falciparum female gametocyte activation assay (Pf FGAA), which assesses stage V female gametocyte viability and functionality using Pfs25 expression. We identify over 400 compounds with activities <2 µM, chemically classified into 57 clusters and 33 singletons. Up to 68% of the hits are chemotypes described for the first time as late-stage gametocyte-targeting molecules. In addition, the biological profile of 90 compounds representing the chemical diversity is assessed. We confirm in vitro transmission-blocking activity of four of the six selected molecules belonging to three distinct scaffold clusters. Overall, this TCAMS gametocyte screen provides 276 promising antimalarial molecules with dual asexual/sexual activity, representing starting points for target identification and candidate selection.