METTL3 promotes renal ischemia-reperfusion injury by modulating miR-374b-5p/SRSF7 axis

Abstract

Renal ischemia–reperfusion injury (IRI) is a prevalent cause of acute kidney injury, however, the regulatory mechanisms of miR-374b-5p in renal IRI remain poorly understood. We established hypoxia/reoxidation (H/R)-induced renal injury models using HK-2 and TCMK-1 cells, as well as an ischemia–reperfusion (I/R)-induced mouse model. Renal tubular epithelial cells (RTECs) viability and apoptosis were assessed using CCK-8, flow cytometry, and TUNEL assays. The targeting relationship between miR-374b-5p and SRSF7 was analyzed using dual luciferase reporter assays. The interaction between METTL3 and miR-374b-5p was confirmed through methylated RNA immunoprecipitation (MeRIP) and co-immunoprecipitation (Co-IP) assays. We found that miR-374b-5p levels were significantly upregulated in H/R-induced HK-2 and TCMK-1 cells. Furthermore, miR-374b-5p promoted H/R-induced RTEC injury by suppressing cell viability and exacerbating apoptosis. SRSF7 was identified as a downstream target of miR-374b-5p, inhibition of SRSF7 reversed the inhibitory effects of miR-374b-5p inhibitors on RTEC injury. Additionally, METTL3 interacted with the microprocessor protein DGCR8 and modulated the processing of pri-miR-374b-5p in an m6A-dependent manner. In the renal IRI model, METTL3 and miR-374b-5p levels were upregulated, and knockdown of METTL3 inhibited apoptosis in H/R-induced HK-2 and TCMK-1 cells. Conversely, miR-374b-5p reversed the protective effects of METTL3 knockdown on renal IRI. Our findings provide novel insights into the role of m6A methylation in the development of renal IRI, demonstrating that METTL3 promotes renal IRI by modulating the miR-374b-5p/SRSF7 axis.