ICMR-National Institute of Pathology, Safdarjung Hospital Campus, New Delhi, 110029, India.
Parasitol Res. 2019 Sep;118(9):2705-2713. doi: 10.1007/s00436-019-06404-9. Epub 2019 Jul 29.
Artemisinin, extracted from a medicinal herb Artemisia annua, is widely used to treat malaria and has shown potent anticancer activity. Artemisinin has been found to be effective against experimental visceral and cutaneous leishmaniasis. Despite extensive research to understand the complex mechanism of resistance to artemisinin, several questions remain unanswered. The artesunate (ART)-resistant line of Leishmania donovani was selected and cellular mechanisms associated with resistance to artemisinin were investigated. ART-resistant (AS-R) parasites showed reduced susceptibility towards ART both at promastigote and amastigote stage compared with ART sensitive (WT) parasites. WT and AS-R parasites were both more susceptible to ART at the early log phase of growth compared with late log phase. AS-R parasites were more infective to the host macrophages (p < 0.05). Evaluation of parasites' tolerance towards host microbicidal mechanisms revealed that AS-R parasites were more tolerant to complement-mediated lysis and nitrosative stress. ROS levels were modulated in presence of ART in AS-R parasites infected macrophages. Interestingly, infection of macrophages by AS-R parasites led to modulated levels of host interleukins, IL-2 and IL-10, in addition to nitric oxide. Additionally, AS-R parasites showed upregulated expression of genes of unfolded protein response pathway including methyltransferase domain-containing protein (HSP40) and flagellar attachment zone protein (prefoldin), that are reported to be associated with ART resistance in Plasmodium falciparum malaria. This study presents in vitro model of artemisinin-resistant Leishmania parasite and cellular mechanisms associated with ART resistance in Leishmania.
青蒿素从药用植物黄花蒿中提取，广泛用于治疗疟疾，并表现出很强的抗癌活性。青蒿素已被证明对实验性内脏和皮肤利什曼病有效。尽管进行了广泛的研究以了解对青蒿素耐药的复杂机制，但仍有几个问题尚未得到解答。选择了抗青蒿琥酯（ART）的利什曼原虫株，并研究了与青蒿素耐药相关的细胞机制。与对青蒿琥酯敏感（WT）寄生虫相比，ART 耐药（AS-R）寄生虫在前对数期生长时对 ART 的敏感性降低，在对数期后期也对 ART 的敏感性降低。WT 和 AS-R 寄生虫在早期对数期生长时对 ART 的敏感性均高于晚期对数期。AS-R 寄生虫对宿主巨噬细胞的感染性更高（p < 0.05）。评估寄生虫对宿主杀菌机制的耐受性表明，AS-R 寄生虫对补体介导的裂解和硝化应激更耐受。在 ART 存在的情况下，感染巨噬细胞的 AS-R 寄生虫中的 ROS 水平被调节。有趣的是，AS-R 寄生虫感染巨噬细胞会导致宿主白细胞介素、IL-2 和 IL-10 的水平发生变化，同时还会产生一氧化氮。此外，AS-R 寄生虫还表现出未折叠蛋白反应途径基因的上调表达，包括甲基转移酶结构域蛋白（HSP40）和鞭毛附着区蛋白（prefoldin），这些基因与疟原虫青蒿素耐药有关。本研究提供了一种体外模型，用于研究抗青蒿素的利什曼寄生虫和与利什曼虫青蒿素耐药相关的细胞机制。
