Department of Ophthalmology, The Affiliated Huaian No.1 People's Hospital of Nanjing Medical University, Huai'an, China.
Department of Chronic Disease Prevention and Control, Huaian City Center for Disease Control and Prevention, Huai'an, China.
Curr Eye Res. 2022 Nov;47(11):1525-1533. doi: 10.1080/02713683.2022.2110264. Epub 2022 Aug 22.
Diabetic retinopathy (DR), the major complication of diabetes, is the leading cause of vision loss and blindness globally. Altered circular RNAs (circRNAs) expression has been found to be involved in DR process. Hence, this work aimed to explore the role and mechanism of circCOL1A2 in DR.
Human retinal microvascular endothelial cells (RMECs) treated with high glucose (HG) were used for functional analysis. Levels of genes and proteins were detected using quantitative real-time polymerase chain reaction and western blotting. In vitro experiments were conducted by transwell, tube formation, CCK-8 assays and ELISA, respectively. The binding interaction between miR-646 and circCOL1A2 or FGF7 (Fibroblast Growth Factor 7) was confirmed using dual-luciferase reporter and RNA immunoprecipitation assays.
CircCOL1A2 was highly expressed in retinal tissues of DR patients and HG-induced RMECs. Then RMECs were exposed to HG treatment to mimic the diabetic conditions in vitro. Functionally, circCOL1A2 knockdown attenuated HG-evoked RMEC migration, proliferation, angiogenesis, blood-retina barrier (BRB) injury and inflammation. Mechanistically, circCOL1A2 functioned as a sponge for miR-646, and miR-646 directly targeted FGF7. Further rescue experiments showed that miR-646 inhibition abated the protective effects of circCOL1A2 knockdown on RMEC function under HG treatment. Besides that, miR-646 was decreased in HG-induced RMECs, re-expression of miR-646 reversed HG-evoked RMEC dysfunction, which was rescued by FGF7 overexpression.
CircCOL1A2 silencing can suppress HG-induced migration, proliferation, angiogenesis, BRB injury and inflammation in RMECs through miR-646/FGF7 axis, suggesting the potential involvement of circCOL1A2 in DR process.
糖尿病视网膜病变（DR）是糖尿病的主要并发症，是全球视力丧失和失明的主要原因。已经发现环状 RNA（circRNA）表达的改变与 DR 过程有关。因此，本研究旨在探讨 circCOL1A2 在 DR 中的作用和机制。
用人高糖（HG）处理的人视网膜微血管内皮细胞（RMECs）进行功能分析。使用实时定量聚合酶链反应和 Western blot 检测基因和蛋白水平。分别通过 Transwell、管形成、CCK-8 测定和 ELISA 进行体外实验。使用双荧光素酶报告和 RNA 免疫沉淀测定证实 miR-646 与 circCOL1A2 或 FGF7（成纤维细胞生长因子 7）之间的结合相互作用。
DR 患者的视网膜组织和 HG 诱导的 RMECs 中高表达 circCOL1A2。然后将 RMECs 暴露于 HG 处理以在体外模拟糖尿病条件。功能上，circCOL1A2 敲低减弱了 HG 诱导的 RMEC 迁移、增殖、血管生成、血视网膜屏障（BRB）损伤和炎症。机制上，circCOL1A2 作为 miR-646 的海绵，而 miR-646 直接靶向 FGF7。进一步的挽救实验表明，在 HG 处理下，抑制 miR-646 减弱了 circCOL1A2 敲低对 RMEC 功能的保护作用。此外，HG 诱导的 RMECs 中 miR-646 减少，miR-646 的重新表达逆转了 HG 诱导的 RMEC 功能障碍，而过表达 FGF7 可挽救这一现象。
circCOL1A2 沉默通过 miR-646/FGF7 轴抑制 HG 诱导的 RMEC 迁移、增殖、血管生成、BRB 损伤和炎症，提示 circCOL1A2 可能参与 DR 过程。
