Dapagliflozin ameliorates high glucose-induced epithelial-mesenchymal transition via up-regulating ACE2 mediated by EZH2 in diabetic nephropathy.

PURPOSE: To investigate the protective function and underlying mechanism of dapagliflozin on tubulointerstitial fibrosis (TIF) in diabetic nephropathy (DN).

METHODS: In this study, we constructed the high-fat and high-glucose diet combined with streptozocin (STZ)-induced DN rat model and 0.2 mg/kg/d of dapagliflozin pretreatment model. After the experiment, kidney tissues were retained for subsequent experiments. In vitro, human renal tubular epithelial cells were treated with different concentrations of glucose and dapagliflozin to investigate the reno-protective functions and potential mechanisms of dapagliflozin in DN.

RESULTS: Our study revealed that dapagliflozin could significantly inhibit epithelial-mesenchymal transition (EMT) and TIF. Meanwhile, dapagliflozin improved cytoskeleton rearrangement and cellular migration capacity. Also, dapagliflozin restored the expression of angiotensin-converting enzyme 2 (ACE2) in human proximal tubular epithelial cells (HK2) and DN rats. Rescue experiments additionally demonstrated that the effects of dapagliflozin were attenuated by blocking ACE2 with MLN-4760, an ACE2 inhibitor, and by siRNA knockdown of ACE2 in HK2 cells. In addition, MLN-4760 and si-ACE2 reversed the decreased pro-fibrotic cytokine TGF-β1 induced by dapagliflozin. Further, results showed that dapagliflozin could inhibit EZH2 and H3K27me3 expression. H3K27me3 partially co-localized with ACE2 and their expression was negatively correlated. Following the over-expression of EZH2, there was a significant up-regulation of H3K27me3 in HK2 cells, then the high expression of ACE2 induced by dapagliflozin was significantly inhibited.

CONCLUSIONS: Dapagliflozin could up-regulate ACE2 by inhibiting EZH2-mediated ACE2 histone methylation, further exerting anti-fibrotic effects by inhibiting downstream activation of TGF-β1.