Objective To observe the effects of empagliflozin (EMPA) on the proliferation, autophagy, and apoptosis of high glucose (HG)-induced glomerular mesangial cells, and to investigate the mechanisms.

Methods Normal group (NG) and HG group were constructed by treating human glomerular mesangial cells with 5 mmol/L and 25 mmol/L glucose, respectively. The HG-induced glomerular mesangial cells were randomly divided into HG + EMPA group (500 nmol/L EMPA treatment), HG + dimethyl sulfoxide (DMSO) group (equal amount of DMSO treatment), HG + anti-miR-con group (transfected with anti-miR-con), and HG + anti-miR-221-3p group (transfected with anti-miR-221-3p, HG + EMPA + miR-con group (transfected with miR-con combined with 500 nmol/L EMPA), and HG + EMPA + miR-221-3p group (transfected with miR-221-3p combined with 500 nmol/L EMPA). Cells were transfected using the liposome method into glomerular mesangial cells. Cell proliferation rate was detected by cell counting kit (CCK8) assay. Protein expressions of multifunctional junction protein (p62) and autophagy microtubule-associated protein light chain 3 antibody Ⅱ (LC3-Ⅱ)/LC3-Ⅰ, G protein-coupled receptor family C, member 5, group A 5A (GPRC5A) were detected by Western blotting. Apoptosis rate was detected by membrane-linked protein V- fluorescein isothiocyanate-propidium iodide (ANNEXIN V- FITC/PI) assay. Dual luciferase reporter gene assay was used to detect the fluorescence activity of cells.

Results Compared with the NG group, the proliferation rate and LC3-Ⅱ/Ⅰ value of the cells in the HG group were significantly lower, and the p62 protein, apoptosis rate, and miR-221-3p expression were significantly higher (P ＜ 0.05). Compared with the HG + DMSO group, cell proliferation rate, LC3-Ⅱ/Ⅰ value were significantly higher, and p62 protein, apoptosis rate, and miR-221-3p expression were significantly lower in the HG + EMPA group (P ＜ 0.05). Compared with the HG + anti-miR-NC group, the proliferation rate, LC3-Ⅱ/Ⅰ value of glomerular mesangial cells were significantly higher, and p62 protein expression, and apoptosis rate were significantly lower in the HG + anti-miR-221-3p group (P ＜ 0.05). Compared with the HG + EMPA + miR-con group, the proliferation rate and LC3-Ⅱ/Ⅰ value of glomerular cells in the HG + EMPA + miR-221-3p group were significantly higher, and p62 protein expression and apoptosis rate were significantly lower (P ＜ 0.05). There was a targeting relationship between miR-221-3p and GPRC5A.

Conclusions EMPA inhibits the HG-induced proliferation and autophagy of glomerular mesangial cells but promots apoptosis, which may be related to the regulation of miR-221-3p/GPRC5A signaling pathway.