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

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.