Circular RNA circ_0000712 regulates high glucose-induced apoptosis, inflammation, oxidative stress, and fibrosis in (DN) by targeting the miR-879-5p/SOX6 axis.

Diabetic nephropathy (DN), a frequent diabetes complication, has complex pathogenesis. Circular RNAs (circRNAs) circ_0000712 has been reported to be upregulated in kidney tissues and high glucose (HG)-inducted Mesangial cells (MCs). This study is designed to explore the role and mechanism of circ_0000712 in the HG-inducted MCs injury in DN. Circ_0000712, microRNA-879-5p (miR-879-5p), and SRY-Box Transcription Factor 6 (SOX6) levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Cell apoptosis was examined by flow cytometry assay. Protein levels of B-cell lymphoma-2 (Bcl-2), Bcl-2 related X protein (Bax), fibronectin (FN), collagen type I (Col. I), collagen type IV (Col. IV), and SOX6 were assessed by western blot assay. Levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α) were measured by enzyme-linked immunosorbent assay (ELISA). Reactive oxygen species (ROS) generation, Lactate Dehydrogenase (LDH) activity, and Superoxide Dismutase (SOD) activity were detected by the corresponding kits. The binding relationship between miR-879-5p and circ_0000712 or SOX6 was predicted by starBase and Targetscan, and then verified by a dual-luciferase reporter and RNA Immunoprecipitation (RIP) assays. Circ_0000712 and SOX6 were highly expressed, and miR-879-5p was decreased in db/db DN mice and HG-inducted SV40-MES13 cells. Furthermore, circ_0000712 deficiency repressed HG-caused apoptosis, inflammation, oxidative stress, and fibrosis in SV40-MES13 cells. Mechanically, circ_0000712 could regulate SOX6 expression by sponging miR-879-5p. Circ_0000712 knockdown could hinder HG-inducted SV40-MES13 cell injury through targeting the miR-879-5p/SOX6 axis, implying a possible circRNA-targeted therapy for DN.