Bhaskar Ashima, Munshi MohamedHusen, Khan Sohrab Zafar, Fatima Sadaf, Arya Rahul, Jameel Shahid, Singh Amit
From the Department of Microbiology and Cell Biology, Centre for Infectious Disease and Research, Indian Institute of Sciences, Bangalore 560012.
From the Department of Microbiology and Cell Biology, Centre for Infectious Disease and Research, Indian Institute of Sciences, Bangalore 560012, the Department of Biotechnology, Jamia Millia Islamia, New Delhi 25, India.
J Biol Chem. 2015 Jan 9;290(2):1020-38. doi: 10.1074/jbc.M114.588913. Epub 2014 Nov 18.
Redox signaling plays a crucial role in the pathogenesis of human immunodeficiency virus type-1 (HIV-1). The majority of HIV redox research relies on measuring redox stress using invasive technologies, which are unreliable and do not provide information about the contributions of subcellular compartments. A major technological leap emerges from the development of genetically encoded redox-sensitive green fluorescent proteins (roGFPs), which provide sensitive and compartment-specific insights into redox homeostasis. Here, we exploited a roGFP-based specific bioprobe of glutathione redox potential (E(GSH); Grx1-roGFP2) and measured subcellular changes in E(GSH) during various phases of HIV-1 infection using U1 monocytic cells (latently infected U937 cells with HIV-1). We show that although U937 and U1 cells demonstrate significantly reduced cytosolic and mitochondrial E(GSH) (approximately -310 mV), active viral replication induces substantial oxidative stress (E(GSH) more than -240 mV). Furthermore, exposure to a physiologically relevant oxidant, hydrogen peroxide (H2O2), induces significant deviations in subcellular E(GSH) between U937 and U1, which distinctly modulates susceptibility to apoptosis. Using Grx1-roGFP2, we demonstrate that a marginal increase of about ∼25 mV in E(GSH) is sufficient to switch HIV-1 from latency to reactivation, raising the possibility of purging HIV-1 by redox modulators without triggering detrimental changes in cellular physiology. Importantly, we show that bioactive lipids synthesized by clinical drug-resistant isolates of Mycobacterium tuberculosis reactivate HIV-1 through modulation of intracellular E(GSH). Finally, the expression analysis of U1 and patient peripheral blood mononuclear cells demonstrated a major recalibration of cellular redox homeostatic pathways during persistence and active replication of HIV.
氧化还原信号传导在1型人类免疫缺陷病毒(HIV-1)的发病机制中起着关键作用。大多数HIV氧化还原研究依赖于使用侵入性技术来测量氧化还原应激,这些技术不可靠,并且无法提供有关亚细胞区室贡献的信息。基因编码的氧化还原敏感绿色荧光蛋白(roGFP)的开发带来了一项重大技术飞跃,它能为氧化还原稳态提供敏感且特定区室的见解。在这里,我们利用了一种基于roGFP的谷胱甘肽氧化还原电位(E(GSH);Grx1-roGFP2)特异性生物探针,并使用U1单核细胞(潜伏感染HIV-1的U937细胞)测量了HIV-1感染各个阶段E(GSH)的亚细胞变化。我们发现,尽管U937和U1细胞的细胞质和线粒体E(GSH)显著降低(约为-310 mV),但活跃的病毒复制会诱导大量氧化应激(E(GSH)超过-240 mV)。此外,暴露于生理相关的氧化剂过氧化氢(H2O2)会导致U937和U1之间亚细胞E(GSH)出现显著偏差,这明显调节了细胞对凋亡的易感性。使用Grx1-roGFP2,我们证明E(GSH)约25 mV的微小增加就足以使HIV-1从潜伏状态转变为重新激活状态,这增加了通过氧化还原调节剂清除HIV-1而不引发细胞生理有害变化的可能性。重要的是,我们发现结核分枝杆菌临床耐药菌株合成的生物活性脂质通过调节细胞内E(GSH)重新激活HIV-1。最后,U1和患者外周血单核细胞的表达分析表明,在HIV持续存在和活跃复制期间,细胞氧化还原稳态途径发生了重大重新校准。