Artemisinin induces lipid peroxidation in Plasmodium falciparum-infected erythrocytes in concentration- and malaria parasite stage-dependent manner

Malaria remained an important and potentially life-threatening infectious disease caused by parasites of the Plasmodium genus. Numerous substances exhibit antimalarial activity, including artemisinin, which has been widely used recently. Artemisinin-based combination therapy (ACT) is recommended for treating Plasmodium falciparum (P.f.) malaria worldwide. Additionally, antitumor, immunomodulatory, and several other therapeutically useful properties of artemisinin are currently under investigation. Different mechanisms of action were proposed for dihydroartemisinin (DHA), the active metabolite of artemisinin, such as eliciting oxidative stress in target cells. The objective of this study is to monitor the generation of reactive oxygen species (ROS) and lipid peroxidation product 4-hydroxynonenal (4-HNE) by DHA in P.f.-infected human erythrocytes. Examining the kinetics of DHA-elicited ROS generation and protein alkylation with4-HNE throughout the parasite maturation process in the host erythrocyte, highest 4-HNE-adduct levels were observed in young “ring forms” of P.f. At low micromolar concentrations, DHA rapidly induced a 2-fold increase of 4-HNE-adducts, which are presumed to be damaging, while no significant increase was elicited by any tested DHA concentration in mature trophozoite stages. Mass spectrometry performed with ring stage proteins revealed extensive modifications of the P.f. protein cysteine proteinase falcipain-1 by 4-HNE, suggesting the conjugation of crucial P.f. proteins with 4-HNE as cause for DHA-elicited parasite death. In conclusion, significant 4-HNE accumulation was detectable after DHA treatment, though, at concentrations well above pharmacologically effective ranges in malaria treatment, but at concentrations useful for antitumor activity. Human cathepsins B, K, and S, which share similarities with falcipain-1 in the active site, are putative targets of DHA in tumor treatment. Hence, lipid peroxidation with subsequent post-translational modification of functionally relevant proteins by 4-HNE, might be considered as uniform mechanism by which DHA potentiates antimalarials' action in ACT and regulates tumor progression. Skorokhod O, Valente E, Mandili G, Ulliers D, Schwarzer E. Micromolar Dihydroartemisinin Concentrations Elicit Lipoperoxidation in Plasmodium falciparum-Infected Erythrocytes. Antioxidants (Basel). 2023 Jul 21;12(7):1468. doi: 10.3390/antiox12071468. PMID: 37508006; PMCID: PMC10376682.