Sreekumar Parameswaran G, Wang Mo, Spee Christine, Sadda Srinivas R, Kannan Ram
The Stephen J. Ryan Initiative for Macular Research (RIMR), Doheny Eye Institute, DVRC 203, 1355 San Pablo Street, Los Angeles, CA 90033, USA.
Department of Ophthalmology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA 90095, USA.
Antioxidants (Basel). 2020 May 12;9(5):411. doi: 10.3390/antiox9050411.
Mitochondrial glutathione (mGSH) is critical for cell survival. We recently reported the localization of OGC (SLC25A11) and DIC (SLC25A10) in hRPE. Herein, we investigated the suppression of OGC and DIC and the effect of αB crystallin chaperone peptide co-treatment on RPE cell death and mitochondrial function. Non-polarized and polarized human RPE were co-treated for 24 h with phenyl succinic acid (PS, 5 mM) or butyl malonic acid (BM, 5 mM) with or without αB cry peptide (75 µg/mL). mGSH levels, mitochondrial bioenergetics, and ETC proteins were analyzed. The effect of mGSH depletion on cell death and barrier function was determined in polarized RPE co-treated with PS, OGC siRNA or BM and αB cry peptide. Inhibition of OGC and DIC resulted in a significant decrease in mGSH and increased apoptosis. mGSH depletion significantly decreased mitochondrial respiration, ATP production, and altered ETC protein expression. αB cry peptide restored mGSH, attenuated apoptosis, upregulated ETC proteins, and improved mitochondrial bioenergetics and biogenesis. mGSH transporters exhibited differential polarized localization: DIC (apical) and OGC (apical and basal). Inhibition of mGSH transport compromised barrier function which was partially restored by αB cry peptide. Our findings suggest mGSH augmentation by its transporters may be a valuable approach in AMD therapy.
线粒体谷胱甘肽（mGSH）对细胞存活至关重要。我们最近报道了OGC（SLC25A11）和DIC（SLC25A10）在人视网膜色素上皮（hRPE）中的定位。在此，我们研究了OGC和DIC的抑制作用以及αB晶状体蛋白伴侣肽联合处理对RPE细胞死亡和线粒体功能的影响。非极化和极化的人RPE细胞分别用苯基琥珀酸（PS，5 mM）或丁基丙二酸（BM，5 mM）联合或不联合αB cry肽（75 µg/mL）处理24小时。分析了mGSH水平、线粒体生物能量学和电子传递链（ETC）蛋白。在用PS、OGC小干扰RNA（siRNA）或BM与αB cry肽联合处理的极化RPE细胞中，确定了mGSH耗竭对细胞死亡和屏障功能的影响。抑制OGC和DIC导致mGSH显著降低并增加细胞凋亡。mGSH耗竭显著降低线粒体呼吸、ATP生成，并改变ETC蛋白表达。αB cry肽恢复了mGSH，减轻了细胞凋亡，上调了ETC蛋白，并改善了线粒体生物能量学和生物发生。mGSH转运体表现出不同的极化定位：DIC（顶端）和OGC（顶端和基部）。抑制mGSH转运损害了屏障功能，而αB cry肽可部分恢复该功能。我们的研究结果表明，通过其转运体增加mGSH可能是年龄相关性黄斑变性（AMD）治疗中的一种有价值的方法。
