Figure 7.
PKC/p38 MAPK, but not ERK1/2 MAPK signaling, mediates Ang II-induced Smad activation. Serum-starved LX-2 cells were preincubated for 0.5 h with CHE (a PKC inhibitor; 10−5 M), SB203580 (a p38 MAPK inhibitor; 10−5 M), or U0126 (an inhibitor of MEK1/2, upstream of ERK1/2 MAPK; 10−6 M) in the presence and absence of Ang II (10−7 M) stimulation for 0.5 h. Cytoplasmic extracts (CE) and nuclear extracts (NE) were prepared and then analyzed by immunoblotting with antibodies against NF-κB p65 and Smad2/3. β-Actin and lamin B1 were used as the internal control for the CE and NE, respectively. (A,D) Representative immunoblot bands for NF-κB p65 and Smad2/3 are shown. Results of (B,E) NF-κB p65 and (C,F) Smad2/3 levels were obtained by densitometric analysis, normalized by the value of the corresponding internal control and expressed relative to the protein level in vehicle control cells (defined as 1-fold). Experiments were repeated 3 times with similar results, and data are presented as mean ± SD. # P < 0.05 versus vehicle-treated control cells; * P < 0.05 versus Ang II-treated cells.