FIGURE 11.

A, Smad3^−/− cells engendered resistance against TGFβ-induced insults. Photomicrographs of Smad3^−/− (left) or Smad3^+/+ (right) cells treated with TGFβ1 (2 ng/ml). Cells were cultured for 24 h in DMEM containing 10% fetal bovine serum and then washed. The medium was replaced with 0.2% bovine serum albumin in DMEM with or without TGFβ1 for 24 or 48 h. The arrows indicate dead cells. B, cell viability of Smad3^−/− cells against TGFβ1-induced insults was estimated using an MTS assay (black bar). C, TGFβ1 failed to suppress Prdx6 expression in Smad3^−/− cells (top, right lane). Western analysis was conducted using cellular extract isolated from Smad3^−/− and Smad3^+/+ cells treated or untreated with TGFβ1. Cell lysate was prepared using radioimmunoprecipitation buffer, samples were resolved on SDS-PAGE, and Western analysis was done with anti-PRDX6 antibody. β-actin was used as loading control. D, Smad3^−/− LECs showed resistance against H₂O₂-induced oxidative stress-mediated damage. Smad3^+/+ (black bars) and Smad3^−/− (gray bar) cells were exposed to H₂O₂ at 100 or 200 μm for 2 h. Cell viability was estimated after 24 h of recovery using an MTS assay.