Evaluation of the Combined Effect of Artemisinin and Ferroptosis Inducer RSL3 against Toxoplasma gondii

Toxoplasma gondiiis a widespread intracellular pathogen that infects humans and a variety of animals. Dihydroartemisinin (DHA), an effective anti-malarial drug, has potential anti-T. gondiiactivity that induces ferroptosis in tumor cells, but the mechanism by which it killsT. gondiiis not fully understood. In this study, the mechanism of DHA inhibitingT. gondiigrowth and its possible drug combinations are described. DHA potently inhibitedT. gondiiwith a half-maximal effective concentration (EC50) of 0.22 μM. DHA significantly increased the ROS level of parasites and decreased the mitochondrial membrane potential, which could be reversed by ferroptosis inhibitors (DFO). Moreover, the ferroptosis inducer RSL3 inhibitedT. gondiiwith an EC50of 0.75 μM. In addition, RSL3 enhanced the DHA-induced ROS level, and the combination of DHA and RSL3 significantly increased the anti-Toxoplasmaeffect as compared to DHA alone. In summary, we found that DHA-induced ROS accumulation in tachyzoites may be an important cause ofT. gondiigrowth inhibition. Furthermore, we found that the combination of DHA and RSL3 may be an alternative to toxoplasmosis. These results will provide a new strategy for anti-Toxoplasmadrug screening and clinical medication guidance.Keywords:Toxoplasma gondii;dihydroartemisinin;ferroptosis inducer RSL3;mitochondrial membrane potential;ROS