Dysregulation of miR‐21‐5p in diabetic nephropathy and its role in inflammatory response

ABSTRACT Background Diabetic nephropathy (DN) is an important microvascular complication of diabetes. MicroRNAs play an important role in the development of DN. Aims This study aims to examine the expression and clinical significance of serum miR‐21‐5p in patients with type 2 diabetes mellitus (T2DM) and DN. Methods This study enrolled a total of 106 T2DM patients, 106 T2DM patients with DN, and 70 healthy individuals. Real‐time fluorescence quantitative PCR (RT‐qPCR) was used to detect the expression of miR‐21‐5p, and the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of miR‐21‐5p in DN. Pearson correlation analysis was performed to examine the association between miR‐21‐5p levels and estimated glomerular filtration rate (eGFR), urinary protein excretion rate (UAER) and other clinicopathological parameters of glomerulonephritis. Furthermore, the effects of miR‐21‐5p on the function and inflammation of human glomerular mesangial cells (HMCs) were analyzed. Results Serum miR‐21‐5p is upregulated in DN and it can effectively distinguish DN patients from T2DM patients. Pearson correlation analysis showed a negative correlation between miR‐21‐5p and eGFR and a positive correlation with UAER. Finally, the knockdown of miR‐21‐5p reduced the levels of pro‐inflammatory cytokines induced by high glucose (HG) and the proliferation of HMCs. Conclusions Serum miR‐21‐5p is upregulated in DN and it might be a diagnostic marker for DN. Furthermore, miR‐21‐5p may be involved in the occurrence and progression of DN by regulating cell proliferation and inflammatory responses and is expected to become a potential therapeutic target for DN.