Biochemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, India-800007.
Int J Biol Macromol. 2020 Dec 15;165(Pt B):2607-2620. doi: 10.1016/j.ijbiomac.2020.10.134. Epub 2020 Oct 22.
T-complex protein-1 (TCP1) is a chaperonin protein known to fold various proteins like actin and tubulin. In Leishmania donovani only one subunit of TCP1 that is gamma subunit (LdTCP1γ) has been functionally characterized. It not only performs ATP dependent protein folding but is also essential for survival and virulence. The present work demonstrates that LdTCP1γ also has a role in miltefosine resistance. Overexpression of LdTCP1γ in L. donovani promastigotes results in decreased sensitivity of parasites towards miltefosine, while single-allele replacement mutants exhibited increased sensitivity as compared to wild-type promastigotes. This response was specific to miltefosine with no cross-resistance to other drugs. The LdTCP1γ-mediated drug resistance was directly related to miltefosine-induced apoptotic death of the parasite, as was evidenced by 2 to 3-fold decrease in cell death parameters in overexpressing cells and >2-fold increase in single-allele replacement mutants. Further, deciphering the mechanism revealed that resistance of overexpressing cells was associated with efficient ROS neutralization due to increased levels of thiols and upregulation of cytosolic tryparedoxin peroxidase (cTxnPx). Further, modulation of LdTCP1γ expression in parasite also modulates the levels of proinflammatory cytokine (TNF-α) and anti-inflammatory cytokine (IL-10) of the host macrophages. The study provides evidence for the involvement of a chaperonin protein LdTCP1γ in the protection against miltefosine induced oxidative damage and reveals the fundamental role of LdTCP1γ in parasite biology.
T 复合物蛋白-1（TCP1）是一种分子伴侣蛋白，已知它可以折叠肌动蛋白和微管蛋白等多种蛋白质。在利什曼原虫中，只有一个 TCP1 的亚基，即γ亚基（LdTCP1γ）具有功能特征。它不仅执行 ATP 依赖性蛋白折叠，而且对于生存和毒力也是必不可少的。目前的工作表明，LdTCP1γ 也在米替福新耐药性中发挥作用。在利什曼原虫前鞭毛体中过表达 LdTCP1γ 会导致寄生虫对米替福新的敏感性降低，而单等位基因替换突变体与野生型前鞭毛体相比表现出更高的敏感性。这种反应是米替福新特有的，与其他药物没有交叉耐药性。LdTCP1γ 介导的耐药性与米替福新诱导寄生虫凋亡死亡直接相关，这可以从前鞭毛体中细胞死亡参数的 2 到 3 倍下降和单等位基因替换突变体中的 2 倍以上增加得到证明。此外，对机制的破译表明，由于巯基水平的增加和细胞质硫氧还蛋白过氧化物酶（cTxnPx）的上调，过表达细胞的耐药性与有效中和 ROS 有关。此外，寄生虫中 LdTCP1γ 表达的调节也调节宿主巨噬细胞中促炎细胞因子（TNF-α）和抗炎细胞因子（IL-10）的水平。该研究为分子伴侣蛋白 LdTCP1γ 参与保护免受米替福新诱导的氧化损伤提供了证据，并揭示了 LdTCP1γ 在寄生虫生物学中的基本作用。
