Fig. 3.

Effects of chronic CS on expression and activation of VEGF receptor 2 (VEGFR2). HPAECs were subjected to 18% CS for 6, 24, or 48 h, stretched at 5% for 24 h, or left under static conditions. HLMVECs were exposed to 18% CS for 24 h. A: time-dependent VEGFR2 expression was monitored by immunoblotting with corresponding antibodies. Equal protein loading was confirmed by determination of β-actin content in total cell lysates. B: CS-induced VEGFR2 tyrosine phosphorylation in ECs exposed to 18% CS and 5% CS was monitored by immunoblotting with phospho-VEGFR2 antibody. C and D: HPAECs grown on Flexcell plates were subjected to CS with or without N-acetyl cysteine (NAC) (1 mM, 30 min) pretreatment. CS-induced VEGFR2 expression was assessed by Western blot analysis. Data are expressed as means ± SD; n = 3, *P < 0.05 vs. 18% CS (C). HPAECs pretreated with NAC or vehicle were exposed to 18% CS (6 h) or static conditions. VEGFR2 tyrosine phosphorylation was monitored by immunoblotting with phospho-VEGFR2 antibody (D). Equal protein loading was confirmed by normalization to β-actin content in the total cell lysates. Results are representative of 3 independent experiments.