Department of Ophthalmology, The Third People's Hospital of Wuxi, Wuxi, Jiangsu 214000, P.R. China.
Mol Med Rep. 2020 Aug;22(2):1072-1080. doi: 10.3892/mmr.2020.11163. Epub 2020 May 20.
Hyperglycemia impairs the retinal functions in patients with diabetic retinopathy (DR). Downregulation of long non‑coding RNA growth arrest‑specific transcript 5 (lncRNA GAS5) expression in diabetes affects glucose intake and insulin signaling. Sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2 (SERCA2) mediates the regulation of endoplasmic reticulum (ER) stress and apoptosis in high glucose (HG)‑treated podocytes. Therefore, the present study aimed to investigate the roles of lncRNA GAS5 and SERCA2 in retinal pigment epithelium cells exposed to HG. GAS5 expression levels were detected using reverse transcription‑quantitative PCR. In addition, the expression levels of SERCA2b, ER stress‑related proteins, pro‑inflammatory factors and apoptotic proteins were determined by western blot analysis, ELISA or flow cytometry. The results showed that HG treatment induced ER stress in ARPE‑19 human adult retinal pigment epithelial cells by upregulating the expression levels of phosphorylated (p)‑protein kinase R‑like ER kinase, p‑eukaryotic initiation factor 2α, activating transcription factor 4 and CCAAT/enhancer‑binding protein homologous protein. In addition, HG treatment induced apoptosis by increasing Bax, Bad and caspase 12, and by decreasing Bcl‑2 levels expression levels. Moreover, HG treatment induced inflammation by upregulating tumor necrosis factor‑α, interleukin (IL)‑1β and IL‑6 expression. However, GAS5 and SERCA2b overexpression significantly decreased ER stress‑related apoptosis and inflammation, whereas SERCA2b knockdown significantly reversed the inhibitory effect of GAS5 on ER stress, apoptosis and inflammation. The results of the present study indicated that GAS5 may suppress ER stress‑induced apoptosis and inflammation by regulating SERCA2b in HG‑treated cells. These data suggested that GAS5 may serve a vital role in the pathogenesis of DR, and it may be considered a potential target for DR therapy.
高血糖会损害糖尿病视网膜病变（DR）患者的视网膜功能。糖尿病中长链非编码 RNA 生长停滞特异性转录物 5（lncRNA GAS5）表达下调会影响葡萄糖摄取和胰岛素信号。肌浆/内质网 Ca2+ATP 酶 2（SERCA2）介导高糖（HG）处理的足细胞内质网（ER）应激和细胞凋亡的调节。因此，本研究旨在探讨 lncRNA GAS5 和 SERCA2 在暴露于 HG 的视网膜色素上皮细胞中的作用。采用逆转录-定量 PCR 检测 GAS5 表达水平。此外，通过 Western blot 分析、ELISA 或流式细胞术测定 SERCA2b、ER 应激相关蛋白、促炎因子和凋亡蛋白的表达水平。结果显示，HG 处理通过上调磷酸化（p）蛋白激酶 R 样 ER 激酶、p 真核起始因子 2α、激活转录因子 4 和 CCAAT/增强子结合蛋白同源蛋白的表达水平，诱导 ARPE-19 人成年视网膜色素上皮细胞 ER 应激。此外，HG 处理通过增加 Bax、Bad 和 caspase 12，减少 Bcl-2 水平表达，诱导细胞凋亡。此外，HG 处理通过上调肿瘤坏死因子-α、白细胞介素（IL）-1β和 IL-6 的表达诱导炎症。然而，GAS5 和 SERCA2b 的过表达显著降低了与 ER 应激相关的凋亡和炎症，而 SERCA2b 的敲低显著逆转了 GAS5 对 ER 应激、凋亡和炎症的抑制作用。本研究结果表明，GAS5 可能通过调节 HG 处理细胞中的 SERCA2b 来抑制 ER 应激诱导的细胞凋亡和炎症。这些数据表明，GAS5 可能在 DR 的发病机制中发挥重要作用，它可能被认为是 DR 治疗的潜在靶点。
