Dysregulated autophagy in the RPE is associated with increased susceptibility to oxidative stress and AMD
Dysregulated autophagy in the RPE is associated with increased susceptibility to oxidative stress and AMD
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DOI：
10.4161/auto.36184
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发表时间：
2014-11-01
期刊：
影响因子：
13.3
通讯作者：
Boulton, Michael
中科院分区：
文献类型：
--
作者：
Mitter, Sayak K.;Song, Chunjuan;Boulton, Michael
自噬失调已被认为存在于包括年龄相关性黄斑变性（AMD）在内的广泛的神经退行性疾病中。为了测试自噬途径是否在保护视网膜色素上皮（RPE）细胞免受氧化应激方面起关键作用，我们将ARPE-19和原代培养的人RPE细胞暴露于急性（3和24小时）和慢性（14天）氧化应激，并在存在或不存在自噬调节剂的情况下通过蛋白质印迹、PCR和自噬体计数监测自噬。急性氧化应激导致RPE中自噬显著增加，而慢性氧化应激下自噬减少。通过雷帕霉素上调自噬减少氧化应激诱导的活性氧（ROS）的产生，而通过3-甲基腺嘌呤（3-MA）或通过敲低ATG 7或BECN 1抑制自噬增加ROS的产生，加剧氧化应激诱导的线粒体活性降低，降低细胞活力，并增加脂褐质。对对照人类供体标本和小鼠的检查表明，自噬体数量和自噬蛋白表达与年龄相关。然而，自噬蛋白、自噬体和自噬通量在来自人供体AMD眼睛和2种AMD动物模型的组织中显著减少。总之，我们的数据证实，自噬在保护RPE免受氧化应激和脂褐素积累方面起着重要作用，自噬的损伤可能加剧氧化应激并有助于AMD的发病机制。
Autophagic dysregulation has been suggested in a broad range of neurodegenerative diseases including age-related macular degeneration (AMD). To test whether the autophagy pathway plays a critical role to protect retinal pigmented epithelial (RPE) cells against oxidative stress, we exposed ARPE-19 and primary cultured human RPE cells to both acute (3 and 24h) and chronic (14 d) oxidative stress and monitored autophagy by western blot, PCR, and autophagosome counts in the presence or absence of autophagy modulators. Acute oxidative stress led to a marked increase in autophagy in the RPE, whereas autophagy was reduced under chronic oxidative stress. Upregulation of autophagy by rapamycin decreased oxidative stress-induced generation of reactive oxygen species (ROS), whereas inhibition of autophagy by 3-methyladenine (3-MA) or by knockdown of ATG7 or BECN1 increased ROS generation, exacerbated oxidative stress-induced reduction of mitochondrial activity, reduced cell viability, and increased lipofuscin. Examination of control human donor specimens and mice demonstrated an age-related increase in autophagosome numbers and expression of autophagy proteins. However, autophagy proteins, autophagosomes, and autophagy flux were significantly reduced in tissue from human donor AMD eyes and 2 animal models of AMD. In conclusion, our data confirm that autophagy plays an important role in protection of the RPE against oxidative stress and lipofuscin accumulation and that impairment of autophagy is likely to exacerbate oxidative stress and contribute to the pathogenesis of AMD.