Transcription Factor FOXO1 Up-regulates AQP2 And Inhibits TGF-β-induced Urothelial Cell Fibrosis

BackgroundBladder outlet obstruction(BOO)is a common urological disease.It and the corresponding lower urinary tract symptoms(such as frequent urination,urgency,urinary incontinence,etc.)seriously affect the quality of life of patients,and may cause a series of complications disease.In recent years,the incidence of bladder outlet obstruction has gradually increased,which has brought great troubles to people’s daily lives.Compensatory hypertrophy of smooth muscle can overcome the resistance of obstruction,which in turn leads to the appearance of bladder fibrosis.Therefore,it is very important to find suitable and effective treatments.However,according to current research,its symptoms are difficult to control because its pathophysiological factors have not been fully studied.Inhibition of TGF-β-induced bladder fibrosis may be another strategy for the treatment of BOO.ObjectiveTo explore the role of AQP2 in TGF-β-induced urothelial cell fibrosis,the influence of AQP2,TGF-β and transcription factor FOXO1 on the level of expression,analyze their interactions,and explore its potential mechanism.MethodsThe human urothelial cell line SV-HUC-1 induced by TGF-β1 was used to establish an in vitro model of bladder fibrosis.Perform cell counting kit(CCK-8)separately,incubate the transfected cells with TGF-β separately(12h,24h,36h),add CCK-8 solution to each well to determine cell viability;For wound healing experiments,the transfected cells were seeded on a six-well plate for incubation to test the cell migration ability.Western blotting was used to measure the level of protein expression of corresponding genes.Luciferase reporter gene assay and chromatin immunoprecipitation assay were used to verify the predicted binding relationship between AQP2 and transcription factor FOXO1.ResultsThrough related experiments,we found that AQP2 was down-regulated in the fibrosis of urothelial cells induced by TGF-β1.The overexpression of AQP2 significantly inhibited the cell viability,migration ability and fibrosis of urothelial cells induced by TGF-β1.In addition,overexpression of the transcription factor FOXO1 played a similar role to AQP2 in urothelial cells,but these changes were eliminated by the knockout of AQP2.FOXO1 can be combined with the promoter of AQP2 to regulate the level of AQP2 expression,thereby affecting the formation of urothelial cell fibrosis.ConclusionThe transcription factor FOXO1 can up-regulate the expression of AQP2 by binding to the promoter of AQP2,and the up-regulated AQP2 can inhibit TGF-β-induced fibrosis of human urothelial cells.This opens up a new treatment idea for the treatment of fibrosis caused by bladder outlet obstruction.