Pradhan Supratim, Dhar Dhruba, Manna Debolina, Chakraborty Shubhangi, Bhattacharyya Arkapriya, Chauhan Khushi, Mukherjee Rimi, Sen Abhik, Pandey Krishna, Das Soumen, Mukherjee Budhaditya
School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur, India.
ICMR-Rajendra Memorial Research Institute of Medical Sciences, Patna, India.
Elife. 2025 May 27;14:RP102857. doi: 10.7554/eLife.102857.
The management of (LD), responsible for fatal visceral leishmaniasis (VL), faces increasing challenges due to rising drug unresponsiveness, leading to increasing treatment failures. While hypolipidemia characterizes VL, LD, a cholesterol auxotroph, relies on host lipid scavenging for its intracellular survival. The aggressive pathology, in terms of increased organ parasite load, observed in hosts infected with antimony-unresponsive-LD (LD-R) as compared to their sensitive counterparts (LD-S), highlights LD-R's heightened reliance on host lipids. Here, we report that LD-R-infection in mice promotes fluid-phase endocytosis in the host macrophages, selectively accumulating neutral lipids while excluding oxidized-low-density lipoprotein (LDL). LD-R enhances the fusion of endocytosed LDL-vesicles with its phagolysosomal membrane and inhibits cholesterol mobilization from these vesicles by suppressing NPC-1. This provides LD-R amastigotes with excess lipids, supporting their rapid proliferation and membrane synthesis. This excess LDL-influx leads to an eventual accumulation of neutral lipid droplets around LD-R amastigotes, thereby increasing their unresponsiveness toward Amphotericin-B, a second-line amphiphilic antileishmanial. Notably, VL patients showing relapse with Amphotericin-B treatment exhibited significantly lower serum LDL and cholesterol than cured cases. Treatment with Aspirin, a lipid droplet blocker, reduced lipid droplets around LD-R amastigotes, restoring Amphotericin-B responsiveness.
负责致死性内脏利什曼病(VL)的杜氏利什曼原虫(LD)管理面临着越来越大的挑战,因为药物无反应性不断增加,导致治疗失败率上升。虽然低脂血症是VL的特征,但作为胆固醇营养缺陷型的LD,依靠宿主脂质清除来实现细胞内存活。与敏感型(LD-S)相比,在感染了锑无反应性-LD(LD-R)的宿主中观察到的器官寄生虫负荷增加方面的侵袭性病理学,突出了LD-R对宿主脂质的高度依赖。在这里,我们报告小鼠体内的LD-R感染促进宿主巨噬细胞的液相内吞作用,选择性积累中性脂质,同时排除氧化型低密度脂蛋白(LDL)。LD-R增强了内吞的LDL囊泡与其吞噬溶酶体膜的融合,并通过抑制NPC-1来抑制这些囊泡中的胆固醇转运。这为LD-R无鞭毛体提供了过量的脂质,支持它们的快速增殖和膜合成。这种过量的LDL流入最终导致LD-R无鞭毛体周围中性脂滴的积累,从而增加它们对二线两亲性抗利什曼药物两性霉素B的无反应性。值得注意的是,接受两性霉素B治疗后复发的VL患者的血清LDL和胆固醇显著低于治愈病例。用脂质滴阻滞剂阿司匹林治疗可减少LD-R无鞭毛体周围的脂滴,恢复对两性霉素B的反应性。
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