FIG. 4.

Effects of rottlerin, a PKC-δ inhibitor, on H₂O₂-induced JAK2 and EGF receptor activation. (A) VSMCs were pretreated with various concentrations of rottlerin as indicated for 30 min and stimulated with H₂O₂ (20 μM) for 10 min. Cell lysates were immunoblotted by antibody toward phospho-JAK2 (JAK2-p). (B) VSMCs were pretreated with rottlerin (10 μM) for 30 min and stimulated with H₂O₂ (20 μM) for 10 min. Cell lysates were immunoblotted by antibodies toward phospho-JAK2, phospho-EGF receptor (EGFR-p), and JAK2. (C) Densitometric analysis of EGF receptor (EGFR) and JAK2 phosphorylation in the immunoblot shown in Fig. 4B. Results are the means ± SEM (n = 4). (D) VSMCs were pretreated with 20 mM N-acetylcysteine (NAC) for 90 min (upper panels) or 10 μM rottlerin for 30 min (lower panels) as indicated and stimulated with AngII (100 nM) for 3 min. Cell lysates were immunoblotted by antibodies toward phospho-JAK2 and JAK2 or phospho-EGF receptor and EGF receptor as indicated. Basal, control sample.