Fig. 6

XBP1-deficient HK2 cells possess profibrotic properties. a XBP1 deficiency enhances the mRNA expression of SNAI1, CTGF and COL4A1 in HK2 cells. b Compared to cells transfected with siNTC, XBP1-deficient HK2 cells secrete elevated levels of active TGF-β1 as assessed by ELISA. c Conditioned medium from XBP1-deficient HK2 induces mRNA expression of CTGF, COL4A1, COL1A1, and TGFβ1 in 293 T cells. d Loss of XBP1sensitizes HK2 cells to TGFβ1-induced cell cycle G2/M arrest. HK2 cells were transfected with indicated siRNA, and 48 h later cells were treated with vehicle (veh) or TGFβ1 (5 ng/mL) for 24 h. Cells were then harvested and subjected to flow cytometric analysis to determine the cell cycle distribution. e The amounts of cells in the G2/M phase of the cell cycle were quantified. Data are expressed as means ± SEM of three independent experiments. *P < 0.05, **P < 0.01, and ***P < 0.001, as compared with siNTC group. ^##P < 0.01 compared between indicated groups