Circular ribonucleic acid nucleoporin 98 knockdown alleviates high glucose‐induced proliferation, fibrosis, inflammation and oxidative stress in human glomerular mesangial cells by regulating the microribonucleic acid‐151‐3p–high mobility group AT‐hook 2 axis

AIMS/INTRODUCTION: This study aimed to investigate the role and mechanism of circular ribonucleic acid nucleoporin 98 (circNUP98) in diabetic nephropathy (DN). MATERIALS AND METHODS: Human glomerular mesangial cells (HMCs) were stimulated with high glucose (HG) to imitate the growth environment of cells under the DN condition. Levels of genes and proteins were tested by quantitative reverse transcription polymerase chain reaction and western blot. Cell proliferation, apoptosis and inflammatory response were analyzed by using cell counting kit‐8, flow cytometry and enzyme‐linked immunosorbent assay analysis, respectively. Oxidative stress and fibrosis were evaluated by detecting the activity of reactive oxygen species, malondialdehyde, superoxide dismutase, fibronectin and collagen IV. The binding interaction between microribonucleic acid (miR)‐151‐3p and high mobility group AT‐hook 2 (HMGA2) or circNUP98 was confirmed using dual‐luciferase reporter, pull‐down and ribonucleic acid immunoprecipitation assays. Exosomes were isolated by ultracentrifugation, and qualified by transmission electron microscopy, nanoparticle tracking analysis and western blot. RESULTS: CircNUP98 expression was higher in the serum of DN patients and HG‐stimulated HMCs. Functionally, circNUP98 knockdown alleviated HG‐induced proliferation, fibrosis, inflammatory response and oxidative stress in HMCs. Mechanistically, circNUP98 directly sponged miR‐151‐3p, which targeted HMGA2. Rescue experiments showed that miR‐151‐3p reversed the inhibitory effects of circNUP98 knockdown on HG‐induced HMC dysfunction. Furthermore, miR‐151‐3p re‐expression also led to an inhibition of the aforementioned biological behaviors, which was attenuated by HMGA2 upregulation. Besides that, CircNUP98 was found to be packaged into exosomes of DN, and exosomal circNUP98 possessed diagnostic value for DN patients. CONCLUSION: CircNUP98 knockdown alleviates HG‐induced proliferation, fibrosis inflammation and oxidative stress in HMCs by regulating the miR‐151‐3p–HMGA2 axis, which might provide a potential approach for DN therapeutics.