Kumari Anjali, Singh Krishn Pratap, Mandal Abhishek, Paswan Ranjeet Kumar, Sinha Preeti, Das Pradeep, Ali Vahab, Bimal Sanjiva, Lal Chandra Shekhar
Division of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of medical Research), Agamkuan, Patna, Bihar, India.
Laboratory of Molecular Biochemistry and Cell Biology, Division of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of medical Research), Agamkuan, Patna, Bihar, India.
PLoS One. 2017 Jun 6;12(6):e0178800. doi: 10.1371/journal.pone.0178800. eCollection 2017.
Leishmaniasis caused by Leishmania parasite is a global threat to public health and one of the most neglected tropical diseases. Therefore, the discovery of novel drug targets and effective drug is a major challenge and an important goal. Leishmania is an obligate intracellular parasite that alternates between sand fly and human host. To survive and establish infections, Leishmania parasites scavenge and internalize nutrients from the host. Nevertheless, host cells presents mechanism like nutrient restriction to inhibit microbial growth and control infection. Zinc is crucial for cellular growth and disruption in its homeostasis hinders growth and survival in many cells. However, little is known about the role of zinc in Leishmania growth and survival. In this study, the effect of zinc on the growth and survival of L.donovani was analyzed by both Zinc-depletion and Zinc-supplementation using Zinc-specific chelator N, N, N', N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN) and Zinc Sulfate (ZnSO4). Treatment of parasites with TPEN rather than ZnSO4 had significantly affected the growth in a dose- and time-dependent manner. The pre-treatment of promastigotes with TPEN resulted into reduced host-parasite interaction as indicated by decreased association index. Zn depletion resulted into flux in intracellular labile Zn pool and increased in ROS generation correlated with decreased intracellular total thiol and retention of plasma membrane integrity without phosphatidylserine exposure in TPEN treated promastigotes. We also observed that TPEN-induced Zn depletion resulted into collapse of mitochondrial membrane potential which is associated with increase in cytosolic calcium and cytochrome-c. DNA fragmentation analysis showed increased DNA fragments in Zn-depleted cells. In summary, intracellular Zn depletion in the L. donovani promastigotes led to ROS-mediated caspase-independent mitochondrial dysfunction resulting into apoptosis-like cell death. Therefore, cellular zinc homeostasis in Leishmania can be explored for new drug targets and chemotherapeutics to control Leishmanial growth and disease progression.
由利什曼原虫寄生虫引起的利什曼病是对公共卫生的全球威胁，也是最被忽视的热带疾病之一。因此，发现新的药物靶点和有效药物是一项重大挑战和重要目标。利什曼原虫是一种专性细胞内寄生虫，在白蛉和人类宿主之间交替。为了生存并建立感染，利什曼原虫寄生虫从宿主中清除并内化营养物质。然而，宿主细胞存在营养限制等机制来抑制微生物生长并控制感染。锌对于细胞生长至关重要，其体内平衡的破坏会阻碍许多细胞的生长和存活。然而，关于锌在利什曼原虫生长和存活中的作用知之甚少。在本研究中，使用锌特异性螯合剂N，N，N'，N'-四（2-吡啶甲基）乙二胺（TPEN）和硫酸锌（ZnSO4）通过锌耗尽和锌补充来分析锌对杜氏利什曼原虫生长和存活的影响。用TPEN而非ZnSO4处理寄生虫以剂量和时间依赖性方式显著影响其生长。用TPEN预处理前鞭毛体导致宿主-寄生虫相互作用减少，如结合指数降低所示。锌耗尽导致细胞内不稳定锌池的通量增加，活性氧生成增加，这与细胞内总硫醇减少以及TPEN处理的前鞭毛体中质膜完整性保留而无磷脂酰丝氨酸暴露相关。我们还观察到TPEN诱导的锌耗尽导致线粒体膜电位崩溃，这与胞质钙和细胞色素c增加有关。DNA片段化分析显示锌耗尽细胞中的DNA片段增加。总之，杜氏利什曼原虫前鞭毛体中的细胞内锌耗尽导致活性氧介导的非半胱天冬酶依赖性线粒体功能障碍，从而导致凋亡样细胞死亡。因此，可以探索利什曼原虫中的细胞锌稳态以寻找新的药物靶点和化学治疗剂，以控制利什曼原虫的生长和疾病进展。
