Fig. 5

SDMA reduces the expression of pro-fibrotic markers in renal cells through STAT4. HK2 human renal epithelial cells were starved overnight and followed by stimulation with TGF-β and treatment with different concentration (0.3–3.3 mg/ml) of STAT4 inhibitor berbamine dihydrochloride for 48 h. The expression of fibronectin, N-cadherin, pSmad3, and STAT4 were analyzed by Western blotting (A, E) and then quantified (B–D, F). HK2 human renal epithelial cells were transfected with nonsense control or STAT4 siRNA (siSTAT4), followed by overnight starvation at 6 h after transfection. On the next day cells were stimulated with TGF-β for another 48 h. The expression of fibronectin, N-cadherin, pSmad3, and STAT4 were analyzed by Western blotting (G, K) and then quantified (H–J, L). HK2 human renal epithelial cells were transfected with nonsense control or STAT4 siRNA, followed by overnight starvation at 6 h after transfection. On the next day cells were stimulated with TGF-β and treated with 10 µM SDMA for another 48 h. The expression of fibronectin, N-cadherin, pSmad3, and STAT4 were analyzed by Western blotting (M, Q) and then quantified (N–P, R). HK2 human renal epithelial cells were transfected with empty vector or STAT4 plasmid (overexpression, OE). On the next day, cells were stimulated with TGF-β and treated with 10 µM SDMA for another 24 h. The expression of fibronectin, N-cadherin, Snail, and STAT4 were analyzed by Western blotting (S) and then quantified (T–W). Data represents mean ± SD. One representative result of at least three independent experiments is shown. NS represents not significant. *p < 0.05. **p < 0.01. ***p < 0.001