hsa_circ_0068631 facilitates the progression of diabetic retinopathy via regulating miR-140-5p in retinal microvascular endothelial cells.

BACKGROUND: Diabetic retinopathy (DR), one of the most prevalent and clinically significant microvascular complications of diabetes mellitus, poses a significant challenge to public health worldwide. Circular RNAs (circRNAs) have emerged as critical regulators of the pathogenesis of various diseases. AIM: To investigate the role and underlying molecular mechanisms of circ_0068631 in the progression of DR. METHODS: Plasma samples were collected from 80 patients with type 2 diabetes mellitus (T2DM) and 160 patients with DR, including 82 with non-proliferative DR (NPDR) and 78 with proliferative DR (PDR). circ_0068631 expression was measured by RT-qPCR, and its risk-predicitve potential for DR was evaluated using receiver operating characteristic (ROC) curves. In vitro experiments were performed using HG-treated human retinal microvascular endothelial cells (hRMECs) to assess cell function and the interaction between circ_0068631 and miR-140-5p. An enzyme-linked immunosorbent assay (ELISA) was utilized to measure the vascular endothelial growth factor (VEGF) concentration. RESULTS: Plasma circ_0068631 was upregulated in DR patients, especially in those with PDR, and displayed high risk-predictive value for distinguishing DR patients from T2DM (AUC = 0.913) and for identifying PDR among DR patients (AUC = 0.884). Silencing circ_0068631 inhibited viability, migration, and VEGF secretion in HG-treated hRMECs. circ_0068631 targeted miR-140-5p, and inhibiting miR-140-5p reversed the effects of circ_0068631 silencing. CONCLUSION: circ_0068631 promotes DR progression by targeting miR-140-5p in hRMECs, serving as a putative blood-based marker for assessing the severity of DR and a therapeutic target for treating DR.