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，每年有超过2.5亿人感染，多达100万人死亡。青蒿素及其衍生物化合物能迅速缓解疟疾症状，比任何其他药物都能更快地清除寄生虫血症。尽管青蒿素药物具有显著的活性和广泛的阶段特异性，但仍有10- 40%的患者在治疗后7 - 28天复发。复发的寄生虫在体外仍然对青蒿素敏感，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接触青蒿素后的复发情况。我们已经证明，暴露于青蒿素药物的环期寄生虫在体外处于休眠状态，并在恢复和恢复细胞周期进程之前持续数小时至数天。此外，我们已经表明，青蒿素敏感和耐药寄生虫进入休眠后，暴露于药物，但耐药线需要提高药物浓度诱导休眠，随后复发早期体外。我们假设，在青蒿素治疗期间休眠寄生虫的形成不仅是治疗失败率和感染复发率高的关键因素，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的调控特征，并确定参与调控它的关键检查点的必要因素。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，通过阶段特异性转录药物反应分析确定对细胞周期进程至关重要的寄生虫基因，并阐明药物诱导的停滞中耐药寄生虫的代谢特征。这种新的研究方法在两个方面具有创新性，即我们将在功能上表征药物诱导的休眠，同时发现潜在的新药靶点和途径。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.