Cholesterol dynamics are essential for the growth and development of Plasmodium falciparum within the erythrocyte

Plasmodium spp. lack de novo cholesterol synthetic pathways and can only scavenge it from their host erythrocyte. Here we report that depletion of cholesterol from the erythrocyte plasma membrane by methyl-β-cyclodextrin (MBCD) has dramatic consequences. The removal of cholesterol results in invasion defects as well as inhibition of parasite development through the intra-erythrocytic cycle. These defects could be rescued by reconstitution with cholesterol and desmosterol but not with epicholesterol. By using live microscopy of fluorescently tagged trophozoite stage parasites, we detected rapid expulsion of the parasites from erythrocyte when exposed to MBCD for just 30 mins. Strikingly, the parasites transition from being intra-erythrocytic to extracellular within 10 seconds and do so without rupturing the erythrocyte membrane. These extruded parasites were still surrounded by the parasitophorous vacuolar membrane (PVM) and remained tethered to the erythrocyte. Electron microscopy revealed that although extracellular parasites retained their PVM, it was heavily compromised. Treatment with antimalarials that disrupt cholesterol homeostasis prior to MBCD exposure prevented the extrusion of trophozoites. These results reveal importance of cholesterol during the intra-erythrocytic development of P. falciparum and the dramatic consequences resulting from tampering with cholesterol content in the infected erythrocyte. These findings suggest dynamic nature of cholesterol within the infected erythrocyte that is critical for parasite survival. ### Competing Interest Statement The authors have declared no competing interest.