Rohrer Bärbel, Bandyopadhyay Mausumi, Beeson Craig
Department of Ophthalmology, Medical University of South Carolina, 167 Ashley Ave, SEI614, 29425, Charleston, SC, USA.
Research Service, Ralph H. Johnson VA Medical Center, Charleston, SC, USA.
Adv Exp Med Biol. 2016;854:793-8. doi: 10.1007/978-3-319-17121-0_106.
One of the affected tissues in age-related macular degeneration (AMD) is the retinal pigment epithelium (RPE), a tissue that consists of terminally differentiated cells and that accumulates damage over time. In all tissues, mitochondria (mt), which play an essential role in both cell health (energy) and death (initiator of apoptosis), undergo an aging process through the accumulation of mtDNA damage, changes in mitochondrial dynamics, a reduction in biogenesis, and mitophagy, leading to an overall reduction in mitochondrial energy production and other non-energy-related functions. Here we have compared energy metabolism in primary human RPE cells isolated from aborted fetus or aged donor eyes and grown as stable monolayers. H2O2 treatment resulted in the generation of reactive oxygen species and superoxide, an effect that was significantly augmented by age. Mitochondrial metabolism, as analyzed by Seahorse respirometry, revealed reduced mitochondrial oxygen consumption (ATP production) at baseline and a complete loss of reserve capacity in aged cells. Likewise, glycolysis was blunted in aged cells. Taken together, these studies showed that RPE cells derived from aged donor eyes are more susceptible to oxidative stress, and exhibit a loss in mitochondrial respiratory reserve capacity and a reduction in glycolysis. These data suggest that while old cells may have sufficient energy at rest, they cannot mount a stress response requiring additional ATP and reducing agents. In summary, these data support the hypothesis that mitochondria or energy metabolism is a valid target for therapy in AMD.
年龄相关性黄斑变性（AMD）中受影响的组织之一是视网膜色素上皮（RPE），这是一种由终末分化细胞组成的组织，随着时间的推移会积累损伤。在所有组织中，线粒体（mt）在细胞健康（能量）和死亡（凋亡启动因子）中都起着至关重要的作用，它会通过mtDNA损伤的积累、线粒体动力学的变化、生物合成的减少以及线粒体自噬而经历衰老过程，导致线粒体能量产生和其他非能量相关功能总体下降。在此，我们比较了从流产胎儿或老年供体眼睛分离并培养成稳定单层的原代人RPE细胞中的能量代谢。过氧化氢处理导致活性氧和超氧化物的产生，这种效应在老年细胞中显著增强。通过海马呼吸测定法分析的线粒体代谢显示，老年细胞在基线时线粒体氧消耗（ATP产生）降低，并且储备能力完全丧失。同样，老年细胞中的糖酵解也受到抑制。综上所述，这些研究表明，来自老年供体眼睛的RPE细胞更容易受到氧化应激的影响，并且表现出线粒体呼吸储备能力丧失和糖酵解减少。这些数据表明，虽然衰老细胞在静息状态下可能有足够的能量，但它们无法产生需要额外ATP和还原剂的应激反应。总之，这些数据支持线粒体或能量代谢是AMD治疗的有效靶点这一假说。
