Epigallocatechin Gallate(EGCG) Improves Epithelial Mesenchymal Transformation Of HK-2 Cells By Inhibiting Autophagy

Objective: Renal interstitial fibrosis(RIF)is caused by multiple reasons and is characterized by excessive deposition of extracellular matrix,which may cause the loss of renal structure and function.RIF is vital and common pathological characteristic of end stage renal disease(ESRD)and can ultimately cause chronic renal failure(CRF).Seeking the valid drug aiming at the mechanism of RIF is considered to be effective for prevention of chronic kidney disease.Epigallocatechin-3-gallate(EGCG)is a polyphenolic compound extracted from green tea in China.Previous study indicated its protective effect on ?-induced acute kidney injury and RIF in UUO mouse models.In vitro research has demonstrated that it can dampen the TGF-?1 induced epithelial mesenchymal transition(EMT)by inhibition the TGF-?/Smad signal pathway.Autophagy,a process that can use lysosomes to degrade their damaged organelles and macromolecules,plays a central role in homeostasis and adaptation to stress.Recent study indicated that TGF-?1-induced autophagy could cause renal tubular injury and subsequent RIF.Furthermore,in vitro study demonstrated the TGF-?1-induced formation of autophagosome in renal proximal tubular cells in time and dose-dependent manner.In the present study,in order to investigate the influence of EGCG on EMT and autophagy in HK-2 cells,we treated the HK-2 cells with EGCG under the stimulation of TGF-?1.These results may reveal the potential role of EGCG on the renal protection and may give us a new idea on the clinical treatment of RIF.Methods: we treated the HK-2 cells with TGF-?1 and induced the EMT of the cells.1)HK-2 cells were treated by TGF-?1 in different concentration.2)Investigate the autophagy and the level of EMT related molecules in TGF-?1 treated HK-2 cells.3)Treat the HK-2 cells by EGCG under the stimulation of TGF-?1 and investigate the autophagy and the level of EMT related molecules.4)Treat the HK-2 cells by sirolimus(autophagic enhancer)or 3-MA(autophgagic inhibitor)under the stimulation of TGF-?1 and investigate the autophagy and the level of EMT related molecules.5)Treat the HK-2 cells by sirolimus(autophagic enhancer)or 3-MA(autophgagic inhibitor)under the stimulation of TGF-?1 and the treatment of EGCG,then investigate the autophagy and the level of EMT related molecules.Results: Under the stimulation of TGF-?1,the increase of a-SMA,LC3 II and Beclin1 together with the decrease of E-cadherin were demonstrated in time and dose-dependent manner.EGCG presents the protective function by dampening the TGF-?1-induced increase of a-SMA,LC3 II and Beclin1 together with the TGF-?1-induced decrease of E-cadherin.Sirolimus,an autophagic enhancer,can inhibit the protective function of EGCG.3-MA,an autophgagic inhibitor,can enhance the protective function of EGCG.Conclusions: 1.TGF-?1 induced the EMT and autophagy in HK-2 cells in time and dose-dependent manner.2.EGCG dampened the EMT and autophagy induced by TGF-?1.3.EMT in HK-2 cells can be regulated by the adjustment of autophagy.4.EGCG can suppress the TGF-?1-induced EMT by autophagy inhibition.