Circular Non-Coding RNA HIPK3 Mediates Retinal Vascular Dysfunction in Diabetes Mellitus
Background—The vascular complications of diabetes mellitus are the major causes of morbidity and mortality among people with diabetes. Circular RNAs (circRNAs) are a class of endogenous non-coding RNAs that regulate gene expression in eukaryotes. In this study, we investigated the role of circRNA in retinal vascular dysfunction induced by diabetes.
Methods—Quantitative polymerase chain reactions, Sanger sequencing, and Northern blots were conducted to detect circHIPK3 expression pattern upon diabetes mellitus-related stresses. MTT assays, EdU incorporation assays, transwell migration assays, and matrigel assays were conducted to detect the role of circHIPK3 in retinal endothelial cell function in vitro. Retinal trypsin digestion, vascular permeability assays, and ELISA assays were conducted to detect the role of circHIPK3 in retinal vascular dysfunction in vivo. Bioinformatics analysis, luciferase activity assays, RNA pull-down assays, and in vitro studies were conducted to reveal the mechanism of circHIPK3-mediated retinal vascular dysfunction.
Results—circHIPK3 expression was significantly up-regulated in diabetic retinas and retinal endothelial cells following stressors related to diabetes. circHIPK3 silencing or over-expressing circHIPK3 changed retinal endothelial cell viability, proliferation, migration, and tube formation in vitro. circHIPK3 silencing in vivo alleviated retinal vascular dysfunction, as shown by decreased retinal acellular capillaries, vascular leakage, and inflammation. circHIPK3 acted as an endogenous miR-30a-3p sponge to sequester and inhibit miR-30a-3p activity, which led to increased VEGFC, FZD4, and WNT2 expression. Ectopic expression of miR-30a-3p mimicked the effect of circHIPK3 silencing on vascular endothelial phenotypes in vivo and in vitro.
Conclusions—The circular RNA circHIPK3 plays a role in diabetic retinopathy by blocking miR-30a function, leading to increased endothelial proliferation and vascular dysfunction. These data suggest that circular RNA is a potential target to control diabetic proliferative retinopathy.
- Received April 23, 2017.
- Revision received August 17, 2017.
- Accepted August 28, 2017.