College of Pharmacy, Binzhou Medical University, Shandong, China.
Non-Clinical Research Department, RemeGen Co., Ltd, Shandong, China.
Aging (Albany NY). 2023 Jul 29;15(15):7513-7532. doi: 10.18632/aging.204917.
Long noncoding RNAs (lncRNAs) play important roles in the development of age-related macular degeneration (AMD). However, the effect of long non-coding RNA activated by DNA damage (NORAD) on AMD remains unknown. This study aimed to investigate the effect of NORAD on RPE cell senescence and degeneration. Irradiated adult retinal pigment epithelial cell line-19 (ARPE-19) and sodium iodate-treated mice were used as and AMD models. Results showed that irradiation-induced AMD characteristics of ARPE-19 and NORAD-knockdown aggravated cell cycle arrest in the G2/M phase, cell apoptosis and cell senescence along with the increased expression of phosphorylated P53 (p-P53) and P21. AMD factors C3, ICAM-1, APP, APOE, and VEGF-A were also increased by NORAD-knockdown. Moreover, NORAD-knockdown increased irradiation-induced reduction of mitochondrial homeostasis factors, (i.e., TFAM and POLG) and mitochondrial respiratory chain complex genes (i.e., ND1 and ND5) along with mitochondrial reactive oxygen species (ROS). We also identified a strong interaction of NORAD and PGC-1α and sirtuin 1 (SIRT1) in ARPE-19; that is, NORAD knockdown increases the acetylation of PGC-1α. In NORAD knockout mice, NORAD-knockout accelerated the sodium iodate-reduced retinal thickness reduction, function impairment and loss of retinal pigment in the fundus. Therefore, NORAD-knockdown accelerates retinal cell senescence, apoptosis, and AMD markers via PGC-1α acetylation, mitochondrial ROS, and the p-P53-P21signaling pathway, in which NORAD-mediated effect on PGC-1α acetylation might occur through the direct interaction with PGC-1α and SIRT1.
长链非编码 RNA（lncRNA）在年龄相关性黄斑变性（AMD）的发展中发挥重要作用。然而，DNA 损伤激活的长非编码 RNA（NORAD）对 AMD 的影响尚不清楚。本研究旨在探讨 NORAD 对 RPE 细胞衰老和变性的影响。辐照成人视网膜色素上皮细胞系-19（ARPE-19）和碘酸钠处理的小鼠分别作为 AMD 模型。结果表明，辐照诱导的 ARPE-19 特征性 AMD 和 NORAD 敲低加剧了细胞周期停滞在 G2/M 期，细胞凋亡和细胞衰老，同时增加了磷酸化 P53（p-P53）和 P21 的表达。AMD 因子 C3、ICAM-1、APP、APOE 和 VEGF-A 也因 NORAD 敲低而增加。此外，NORAD 敲低增加了辐照诱导的线粒体稳态因子（TFAM 和 POLG）和线粒体呼吸链复合物基因（ND1 和 ND5）以及线粒体活性氧（ROS）的减少。我们还在 ARPE-19 中鉴定出 NORAD 与 PGC-1α 和沉默调节蛋白 1（SIRT1）之间的强烈相互作用；即 NORAD 敲低增加了 PGC-1α 的乙酰化。在 NORAD 敲除小鼠中，NORAD 敲除加速了碘酸钠减少的视网膜厚度减少、功能障碍和眼底视网膜色素丧失。因此，NORAD 敲低通过 PGC-1α 乙酰化、线粒体 ROS 和 p-P53-P21 信号通路加速视网膜细胞衰老、凋亡和 AMD 标志物的产生，其中 NORAD 介导的 PGC-1α 乙酰化作用可能通过与 PGC-1α 和 SIRT1 的直接相互作用发生。
