Double-kill mechanism of artemisinin against Plasmodium

Abstract Artemisinin and its derivatives (ARTs) can kill malaria parasites, but its mechanism remains unclear. Haem or iron (HI) was proposed to activate ARTs to produce free radicals that kill malaria parasites. However, our results revealed that adding iron supply did not enhance the antimalarial effect of ARTs but attenuated this effect, strongly suggesting that its free radical effect was not its only antimalarial mechanism. Single-cell RNA sequencing analysis of Plasmodium yoelii 17XNL-infected erythrocytes revealed that the stages most sensitive to ARTs were closely associated with the expression of haem- and iron- related, DNA synthesis-related, antioxidation-related, and pentose-phosphate-pathway-related genes, simultaneously accompanied with the release and utilization of HI. In addition, ARTs were found to combine with haem to form adducts and disturb the normal aggregation of hemozoin in parasites. In particular, adding iron supply antagonized the antimalarial effect of ARTs in vivo and in vitro, strongly suggesting that ARTs trap HI and disturb the requirement of parasites dependent of HI, thereby resulting in the antimalarial effect, which is likely similar to the antimalarial mechanism of iron chelators. Thus, the iron chelator effect with free radical effect renders ARTs the double-kill antimalarial mechanism.