Antimalarial Action of Artesunate Involves DNA Damage Mediated by Reactive Oxygen Species
Antimalarial Action of Artesunate Involves DNA Damage Mediated by Reactive Oxygen Species
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DOI：
10.1128/aac.03663-14
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发表时间：
2015-01-01
影响因子：
4.9
通讯作者：
Kumar, Nirbhay
中科院分区：
文献类型：
--
作者：
Gopalakrishnan, Anusha M.;Kumar, Nirbhay
以青蒿素为基础的联合疗法是推荐的治疗恶性疟原虫疟疾的一线疗法。已经表明青蒿素的细胞毒性作用是由自由基介导的，随后是恶性疟原虫蛋白的烷基化。内过氧化物桥，青蒿素衍生物的活性部分，在亚铁存在下裂解，产生活性氧（ROS）和其他自由基。然而，恶性疟原虫对青蒿素耐药性的出现突出表明，需要对青蒿素抗疟活性的分子机制有新的认识。在这里，我们表明青蒿琥酯（ART）诱导恶性疟原虫DNA双链断裂在生理相关的剂量和时间依赖性的方式。ART诱导的DNA损伤伴随着寄生虫细胞内ROS水平的增加。ROS清除剂甘露醇可逆转ART的细胞毒性作用并减少DNA损伤，谷胱甘肽（GSH）水平的调节可影响ART诱导的ROS和DNA损伤。ROS的积累、DNA损伤的增加以及由此产生的抗寄生虫作用表明ROS、DNA损伤和寄生虫死亡之间存在因果关系。最后，我们还表明，ART诱导的ROS的产生涉及NADPH氧化酶，一种酶参与超氧阴离子的生产的潜在作用。我们对恶性疟原虫的研究结果为以前未知的青蒿素衍生物抗疟活性的分子机制提供了新的见解，并可能有助于设计针对最毒疟原虫物种的下一代抗疟药物。
Artemisinin-based combination therapy (ACT) is the recommended first-line treatment for Plasmodium falciparum malaria. It has been suggested that the cytotoxic effect of artemisinin is mediated by free radicals followed by the alkylation of P. falciparum proteins. The endoperoxide bridge, the active moiety of artemisinin derivatives, is cleaved in the presence of ferrous iron, generating reactive oxygen species (ROS) and other free radicals. However, the emergence of resistance to artemisinin in P. falciparum underscores the need for new insights into the molecular mechanisms of antimalarial activity of artemisinin. Here we show that artesunate (ART) induces DNA double-strand breaks in P. falciparum in a physiologically relevant dose-and time-dependent manner. DNA damage induced by ART was accompanied by an increase in the intracellular ROS level in the parasites. Mannitol, a ROS scavenger, reversed the cytotoxic effect of ART and reduced DNA damage, and modulation of glutathione (GSH) levels was found to impact ROS and DNA damage induced by ART. Accumulation of ROS, increased DNA damage, and the resulting antiparasite effect suggest a causal relationship between ROS, DNA damage, and parasite death. Finally, we also show that ART-induced ROS production involves a potential role for NADPH oxidase, an enzyme involved in the production of superoxide anions. Our results with P. falciparum provide novel insights into previously unknown molecular mechanisms underlying the antimalarial activity of artemisinin derivatives and may help in the design of next-generation antimalarial drugs against the most virulent Plasmodium species.