Functional Characterization of Artemisinin-induced Dormancy

描述（由申请人提供）：疟疾是世界范围内的一个主要健康问题，每年有2.5亿多人受到感染，多达100万人死亡。青蒿素及其衍生物化合物可迅速缓解疟疾症状，清除寄生虫病的速度比任何其他药物都快。尽管青蒿素药物具有显著的活性和广泛的分期特异性，但在治疗后7至28天，仍有10- 40%的患者出现感染复发。在体外，复发性寄生虫仍然对青蒿素敏感，这表明治疗失败的高频率不是由于传统的耐药机制。我们在体外和体内研究了暴露于青蒿素后的复发。我们已经证明，暴露于青蒿素药物的环期寄生虫在体外恢复和恢复细胞周期进程之前会进入休眠状态，并持续数小时至数天。此外，我们已经证明，对青蒿素敏感和耐药的寄生虫在暴露于药物后都会进入休眠状态，但耐药品系需要提高药物浓度来诱导休眠，随后在体外更早地复发。我们推测，在青蒿素治疗期间，休眠寄生虫的形成不仅是治疗失败率高和感染复发的关键因素，而且也是对青蒿素类药物产生耐药性的关键因素。这些研究的长期目标是确定恶性疟原虫细胞周期停滞和休眠的新调控特征，并确定参与调节其关键检查点的关键因素。在这些研究中，我们将描述恶性疟原虫休眠的转录调控过程，通过特定阶段的转录药物反应分析鉴定对细胞周期进程至关重要的寄生虫基因，并阐明耐药寄生虫在药物诱导阻滞中的代谢特征。这种新颖的研究方法在两个方面具有创新性，即我们将从功能上表征药物诱导的休眠，同时发现潜在的新药物靶点和途径。该项目将使我们能够更好地了解寄生虫药物逃避策略的机制，并使我们能够设计更好的药物来治疗和预防这种疾病。

DESCRIPTION (provided by applicant): Malaria is a major health problem worldwide, with over 250 million people becoming infected and up to 1 million deaths annually. Artemisinin and derivative compounds provide rapid relief of malaria symptoms with faster clearance of parasitemia than any other drugs. Despite the remarkable activity and broad stage specificity of artemisinin drugs, between 10-40 percent of patients experience recrudescence of the infection 7 to 28 days post-treatment. The recrudescent parasites remain susceptible to artemisinin in vitro, suggesting that the high frequency of treatment failure is not due to conventional resistance mechanisms. We have investigated recrudescence following exposure to artemisinin in vitro and in vivo. We have shown that ring stage parasites exposed to artemisinin drugs become dormant and persist in this arrested state for hours to days in vitro before recovering and resuming cell cycle progression. Furthermore, we have shown that both artemisinin sensitive and resistant parasites enter dormancy following exposure to drug, yet resistant lines require elevated drug concentrations to induce dormancy and subsequently recrudesce earlier in vitro. We hypothesize that the formation of dormant parasites during artemisinin treatment is not only a key factor in the high rates of treatment failure and recrudescence of infection, but also in the development of resistance to the artemisinin class of drugs. The long-term objective of these studies is to define the novel regulatory features of cell cycle arrest and dormancy in Plasmodium falciparum, and identify the essential factors involved in the key checkpoints that regulate it. In these studies, we will characterize the transcriptional regulatory processes of Plasmodium falciparum dormancy, identify parasite genes essential for cell cycle progression through stage-specific transcriptional drug response analyses, and elucidate the metabolic signatures of resistant parasites in drug-induced arrest. This novel research approach is innovative in two ways in that we will be functionally characterizing drug-induced dormancy, as well as simultaneously uncovering potential new drug targets and pathways. This project will enable us to grasp a better understanding of the mechanisms of parasite drug evasion strategies, and allow us to design better drugs to treat and prevent this disease.