Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200072, China.
Department of Ophthalmology, Anhui University of Science and Technology, Huainan, Anhui 232001, China.
Biomed Res Int. 2021 Nov 1;2021:6666506. doi: 10.1155/2021/6666506. eCollection 2021.
Age-related macular degeneration (AMD) is a multifactor disease, which is primarily characterized by retinal pigment epithelium (RPE) cell loss. Since the retina is the most metabolically active tissue, RPE cells are exposed to consistent oxidative environment. So, oxidation-induced RPE cell death has long been considered a contributor to the onset of AMD. Here, we applied a retinal degeneration (RD) rat model induced by blue light-emitting diode (LED) and a cell model constructed by HO stimulus to mimic the prooxidant environment of the retina. We detected that the expression of miR-27a was upregulated and the expression of FOXO1 was downregulated in both models. So, we furtherly investigated the role of miR-27a-FOXO1 axis in RPE in protesting against oxidants. Lentivirus-mediated RNA was injected intravitreally into rats to modulate the miR-27a-FOXO1 axis. Retinal function and histopathological changes were evaluated by electroretinography (ERG) analysis and hematoxylin and eosin (H&E) staining, respectively. Massive photoreceptor and RPE cell death were examined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The damage to the retina was aggravated in the FOXO1 gene-knockdown and miR-27a-overexpression groups after exposure to LED but was alleviated in the FOXO1 gene-overexpression or miR-27a-knockdown groups. Dual luciferase assay was used to detect the binding site of miR-27a and FOXO1. Upregulated miR-27a inhibited the expression of FOXO1 by directly binding to the FOXO1 mRNA 3'UTR and decreased the autophagy activity of ARPE-19 cells, resulting in the accumulation of reactive oxygen species (ROS) and decrease of cell viability. The results suggest that miR-27a is a negative regulator of FOXO1. Also, our data emphasize the prominent role of miR-27a/FOXO1 axis in modulating ROS accumulation and cell death in RPE cell model under oxidative stress and influencing the retinal function in the LED-induced RD rat model.
年龄相关性黄斑变性（AMD）是一种多因素疾病，主要表现为视网膜色素上皮（RPE）细胞丧失。由于视网膜是新陈代谢最活跃的组织，RPE 细胞长期暴露在持续的氧化环境中。因此，氧化诱导的 RPE 细胞死亡一直被认为是 AMD 发病的原因之一。在这里，我们应用蓝光发光二极管（LED）诱导的视网膜变性（RD）大鼠模型和 HO 刺激构建的细胞模型来模拟视网膜的促氧化剂环境。我们检测到两种模型中 miR-27a 的表达上调，FOXO1 的表达下调。因此，我们进一步研究了 miR-27a-FOXO1 轴在 RPE 中对抗氧化剂的作用。通过将慢病毒介导的 RNA 注入大鼠玻璃体腔来调节 miR-27a-FOXO1 轴。通过视网膜电图（ERG）分析和苏木精和伊红（H&E）染色分别评估视网膜功能和组织病理学变化。通过末端脱氧核苷酸转移酶介导的 dUTP 缺口末端标记（TUNEL）检测大量光感受器和 RPE 细胞死亡。在暴露于 LED 后，FOXO1 基因敲低和 miR-27a 过表达组的视网膜损伤加重，但 FOXO1 基因过表达或 miR-27a 敲低组的损伤减轻。双荧光素酶测定用于检测 miR-27a 和 FOXO1 的结合位点。上调的 miR-27a 通过直接结合 FOXO1 mRNA 3'UTR 抑制 FOXO1 的表达，降低 ARPE-19 细胞的自噬活性，导致活性氧（ROS）积累和细胞活力下降。结果表明，miR-27a 是 FOXO1 的负调节剂。此外，我们的数据强调了 miR-27a/FOXO1 轴在氧化应激下调节 RPE 细胞模型中 ROS 积累和细胞死亡以及影响 LED 诱导的 RD 大鼠模型中视网膜功能方面的重要作用。
