MiR-208a-3p regulated by circUQCRC2 suppresses ischemia/reperfusion-induced acute kidney injury by inhibiting CELF2-mediated tubular epithelial cell apoptosis, inflammation and ferroptosis.

Abstract

Acute kidney injury (AKI) is a prevalent clinical syndrome with persistent kidney dysfunction. Renal ischemia/reperfusion (I/R) injury is a major cause of AKI. miR-208a-3p overexpression attenuated myocardial I/R injury. This study aims to investigate the role and mechanism of miR-208a-3p in I/R-induced AKI. AKI models were established using hypoxia/reoxygenation (H/R)-exposed tubule epithelial cell HK-2 and I/R-induced mice. The function and mechanism of miR-208a-3p were investigated by gain-or loss-of-function methods using real-time PCR, CCK-8, flow cytometry, ELISA, western blot, hematoxylin-eosin staining, Tunel assay, detection of Fe2+, ROS, BUN and Creatinine, and luciferase reporter assay. miR-208a-3p expression was suppressed, while the expression of CELF2 and circular RNA ubiquinol-cytochrome c reductase core protein 2 (circUQCRC2) was increased in both AKI models. miR-208a-3p upregulation or circUQCRC2 silencing increased the viability, decreased the levels of proinflammatory cytokines (TNF-α, IL-1β and IL-6), reduced apoptosis and contents of Fe2+ and ROS, elevated expression of GPX4 and SLC7A11, reduced ACSL4 expression in H/R-stimulated HK-2 cells. Also, miR-208a-3p improved kidney function by alleviating renal injury, apoptosis, inflammation and ferroptosis in AKI mouse model. CELF2 was a target gene of miR-208a-3p which was negatively modulated by circUQCRC2. Overexpression of CELF2 blocked the function of miR-208a-3p upregulation or circUQCRC2 silencing on H/R-treated HK-2 cells. Moreover, the effects of circUQCRC2 downregulation on H/R-injured cells were also reversed by miR-208a-3p inhibitor. miR-208a-3p regulated by circUQCRC2 could attenuate I/R-induced AKI by inhibiting CELF2-mediated tubular epithelial cell apoptosis, inflammation and ferroptosis. This study provides potential therapeutic targets for I/R-induced AKI.