School of Pharmacy, University of Eastern Finland, Kuopio, Finland.
Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.
Oxid Med Cell Longev. 2019 Mar 17;2019:1583656. doi: 10.1155/2019/1583656. eCollection 2019.
Mitochondrial dysfunction has been implicated in a wide variety of degenerative diseases, including age-related macular degeneration. Damage to mitochondria and mitochondrial DNA accumulates with age in the postmitotic retinal pigment epithelium (RPE), which could lead to RPE cell death and trigger disease. One possible mechanism for cells to avoid cell death is mitophagy, the targeted clearance of damaged mitochondria by autophagy. Here, we induced mitochondrial damage in human RPE cells (ARPE-19 and hRPE), using antimycin A, an inhibitor of complex III of the electron transport chain, and investigated cellular viability, mitochondrial structure and function, and autophagy activity. We observed that antimycin A evoked dose-dependent cell death, a rapid loss in mitochondrial membrane potential, and a collapse of oxidative phosphorylation. Mitochondria appeared swollen and there was clear damage to their cristae structure. At the same time, cells were undergoing active autophagy and were sensitive to autophagy inhibition by bafilomycin A1 or chloroquine. These results indicate that mitochondrial dysfunction can cause significant RPE damage and that autophagy is an important survival mechanism for cells suffering from mitochondrial damage.
线粒体功能障碍与多种退行性疾病有关，包括年龄相关性黄斑变性。有丝分裂后视网膜色素上皮 (RPE) 中线粒体和线粒体 DNA 的损伤随年龄的增长而积累，这可能导致 RPE 细胞死亡并引发疾病。细胞避免细胞死亡的一种可能机制是自噬介导的靶向清除受损线粒体，即线粒体自噬。在这里，我们使用电子传递链复合物 III 的抑制剂抗霉素 A 诱导人 RPE 细胞 (ARPE-19 和 hRPE) 中的线粒体损伤，并研究了细胞活力、线粒体结构和功能以及自噬活性。我们观察到抗霉素 A 引起了剂量依赖性的细胞死亡、线粒体膜电位的快速丧失以及氧化磷酸化的崩溃。线粒体看起来肿胀，嵴结构明显受损。与此同时，细胞正在进行活跃的自噬，并且对自噬抑制剂巴弗洛霉素 A1 或氯喹敏感。这些结果表明，线粒体功能障碍可导致 RPE 明显损伤，自噬是遭受线粒体损伤的细胞的重要存活机制。
