Targeting the Cell Stress Response of Plasmodium falciparum to Overcome Artemisinin Resistance
Targeting the Cell Stress Response of Plasmodium falciparum to Overcome Artemisinin Resistance
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DOI：
10.1371/journal.pbio.1002132
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发表时间：
2015-04-01
期刊：
影响因子：
9.8
通讯作者：
Tilley, Leann
中科院分区：
文献类型：
--
作者：
Dogovski, Con;Xie, Stanley C.;Tilley, Leann
恶性疟疾的成功控制在很大程度上取决于青蒿素联合疗法的治疗。因此，关于出现对青蒿素的耐药性以及这种耐药性的流行正在增加的报告令人震惊。抗逆转录病毒耐药性最近与K13螺旋桨蛋白的突变有关。我们对来自柬埔寨（Pailin）地区的恶性疟原虫K13野生型和突变株的药物反应进行了详细的动力学分析。我们证明抗逆转录病毒治疗诱导生长迟缓和泛素化蛋白的积累，表明细胞应激反应参与泛素/蛋白酶体系统。我们发现耐药寄生虫表现出较低水平的泛素化蛋白和延迟的细胞死亡，表明细胞应激反应增强。我们发现可以通过抑制蛋白酶体来靶向应激反应。因此，临床上使用的蛋白酶体抑制剂对敏感和耐药寄生虫（包括表达突变型或野生型K13的等基因系）的抗逆转录病毒治疗活性都有很强的协同作用。在体内也观察到对伯氏疟原虫的协同作用。我们开发了一个详细的寄生虫反应模型，使我们能够首次从体外评估ART敏感性中推断体内寄生虫清除概况。我们提供的证据表明，耐药的临床标志（延迟寄生虫清除）是药物疗效的间接衡量标准，因为在循环中存在形态不变的无法存活的寄生虫，我们建议直接测量生存能力的替代方法。我们的模型预测，将目前为期三天的抗逆转录病毒治疗疗程延长至四天，或者将剂量分开，将有效清除耐药的寄生虫感染。这项工作为改进抗逆转录病毒药物耐药性的现场检测和可用于抗逆转录病毒药物耐药性地区的治疗策略提供了依据。
Successful control of falciparum malaria depends greatly on treatment with artemisinin combination therapies. Thus, reports that resistance to artemisinins (ARTs) has emerged, and that the prevalence of this resistance is increasing, are alarming. ART resistance has recently been linked to mutations in the K13 propeller protein. We undertook a detailed kinetic analysis of the drug responses of K13 wild-type and mutant isolates of Plasmodium falciparum sourced from a region in Cambodia (Pailin). We demonstrate that ART treatment induces growth retardation and an accumulation of ubiquitinated proteins, indicative of a cellular stress response that engages the ubiquitin/proteasome system. We show that resistant parasites exhibit lower levels of ubiquitinated proteins and delayed onset of cell death, indicating an enhanced cell stress response. We found that the stress response can be targeted by inhibiting the proteasome. Accordingly, clinically used proteasome inhibitors strongly synergize ART activity against both sensitive and resistant parasites, including isogenic lines expressing mutant or wild-type K13. Synergy is also observed against Plasmodium berghei in vivo. We developed a detailed model of parasite responses that enables us to infer, for the first time, in vivo parasite clearance profiles from in vitro assessments of ART sensitivity. We provide evidence that the clinical marker of resistance (delayed parasite clearance) is an indirect measure of drug efficacy because of the persistence of unviable parasites with unchanged morphology in the circulation, and we suggest alternative approaches for the direct measurement of viability. Our model predicts that extending current three-day ART treatment courses to four days, or splitting the doses, will efficiently clear resistant parasite infections. This work provides a rationale for improving the detection of ART resistance in the field and for treatment strategies that can be employed in areas with ART resistance.