Artemisinin (ART)-based combination therapies are recommended as first- and second-line treatments for Plasmodium falciparum malaria. Here, we investigated the impact of the RecQ inhibitor ML216 on the repair of ART-mediated damage in the genome of P. falciparum. PfBLM and PfWRN were identified as members of the RecQ helicase family in P. falciparum. However, the role of these RecQ helicases in DNA double-strand break (DSB) repair in this parasite has not been explored. Here, we provide several lines of evidence to establish the involvement of PfBlm in DSB repair in P. falciparum. First, we demonstrate that PfBlm interacts with two well-characterized DSB repair proteins of this parasite, namely, PfRad51 and PfalMre11. Second, we found that PfBLM expression was upregulated in response to DNA-damaging agents. Third, through yeast complementation studies, we demonstrated that PfBLM could complement the DNA damage sensitivity of a Δsgs1 mutant of Saccharomyces cerevisiae, in contrast to the helicase-dead mutant PfblmK83R. Finally, we observe that the overexpression of PfBLM induces resistance to DNA-damaging agents and offers a survival advantage to the parasites. Most importantly, we found that the RecQ inhibitor ML216 inhibits the repair of DSBs and thereby renders parasites more sensitive to ART. Such synergism between ART and ML216 actions was observed for both drug-sensitive and multidrug-resistant strains of P. falciparum. Taken together, these findings establish the implications of PfBlm in the Plasmodium DSB repair pathway and provide insights into the antiparasitic activity of the ART-ML216 combination.

中文翻译：

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阐明 PfBlm 的 DNA 修复功能和 RecQ Helicase 小分子抑制剂对青蒿素作用的增强

推荐以青蒿素 (ART) 为基础的联合疗法作为恶性疟原虫疟疾的一线和二线治疗方法。在这里，我们研究了 RecQ 抑制剂 ML216 对恶性疟原虫基因组中 ART 介导的损伤修复的影响。PfBLM和PfWRN被确定为恶性疟原虫RecQ 解旋酶家族的成员。然而，尚未探索这些 RecQ 解旋酶在该寄生虫的 DNA 双链断裂 (DSB) 修复中的作用。在这里，我们提供了几条证据来确定 PfBlm 参与恶性疟原虫的DSB 修复. 首先，我们证明 PfBlm 与该寄生虫的两种特征明确的 DSB 修复蛋白相互作用，即 PfRad51 和 PfalMre11。其次，我们发现PfBLM表达因 DNA 损伤剂而上调。第三，通过酵母互补研究，我们证明PfBLM可以补充酿酒酵母Δ sgs1突变体的 DNA 损伤敏感性，与解旋酶死亡突变体PfblmK83R形成对比。最后，我们观察到PfBLM的过度表达诱导对 DNA 损伤剂的抗性，并为寄生虫提供生存优势。最重要的是，我们发现 RecQ 抑制剂 ML216 抑制 DSB 的修复，从而使寄生虫对 ART 更加敏感。对于恶性疟原虫的药物敏感和多重耐药菌株，都观察到了 ART 和 ML216 作用之间的这种协同作用。总之，这些发现确定了 PfBlm 在疟原虫DSB 修复途径中的意义，并提供了对 ART-ML216 组合的抗寄生虫活性的见解。