Glideosomal GAP50 binders that inhibit invasion and restrict malaria parasite in vitro and in vivo

Abstract

Malaria continues to be a killer disease even in the modern world. Vaccines and drugs have a lot to learn from the malaria parasite before they can be successful. Here, using a filter for glideosomal anchor protein PfGAP50, we have explored a plethora of small molecules to shortlist eight GAP50 binders with promising antiplasmodial activity (IC50 < 3 µM) that are also highly selective. Of these, Hayatinin, Bedaquiline, MMV688271, Curine, and Brilacidin with PfINDO IC50 ≤ 1 µM were found to stall merozoites invasion by inhibiting IMC formation besides increasing ROS levels in trophozoites. Bedaquiline loaded healthy RBCs showed prophylactic ability to prevent intraerythrocytic development of malaria parasite. Synergistic activities with ΣFIC values as low as 0.22 (Curine and Artemisinin) or 0.37 (Bedaquiline and Artemisinin) augur well for the development of drug combinations to combat malaria effectively. Interestingly, orally delivered Bedaquiline (50 mg/Kg b. wt.) showed substantial suppression of parasitemia in the mouse model of malaria.