Figure 7

Role for MAP kinases in apical TGF-β-mediated secretion of CTGF. A: Polarized hPTEC were incubated with inhibitors (U0: U0106, 1 μM; SB203: SB203580, 1 μM; Y27: Y27632, 10 μM; SB43: SB431542: 10 μM) for 30 min and then stimulated with TGF-β from the apical side for 6 h. CTGF secretion was detected in the apical compartment. The graph summarizes means +/− SD of 3 independent experiments. Secretion of CTGF in TGF-β-stimulated cells was set to 1 in each experiment. ** p < 0.01, * p < 0.05 compared to TGF-β-stimulated cells, Dunnet’s multiple comparison test. B: Polarized hPTECs were stimulated in duplicate with TGF-β for 15 and 60 min from the apical side. Protein was isolated from polarized cells. ERK1/2 and phospho-ERK1/2 were detected by Western blotting.