ANGIOTENSIN II-INDUCED VASCULAR SMOOTH MUSCLE CELL MIGRATION AND GROWTH ARE MEDIATED BY CYTOCHROME P450 1B1-DEPENDENT SUPEROXIDE GENERATION

摘要

Cytochrome P450 1B1, expressed in vascular smooth muscle cells, can metabolize arachidonic acid in vitro into several products including 12- and 20-hydroxyeicosatetraenoic acids that stimulate vascular smooth muscle cell growth. This study was conducted to determine if cytochrome P450 1B1 contributes to angiotensin II-induced rat aortic smooth muscle cell migration, proliferation and protein synthesis. Ang II stimulated migration of these cells, measured by the wound healing approach, by 1.78 fold and DNA synthesis, measured by [³H]thymidine incorporation, by 1.44 fold after 24 hours, and protein synthesis, measured by [³H]leucine incorporation, by 1.40 fold after 48 hours. Treatment of vascular smooth muscle cells with the cytochrome P450 1B1 inhibitor, 2, 4, 3′, 5′-tetramethoxystilbene, or transduction of these cells with adenovirus cytochrome P450 1B1 shRNA, but not its scrambled control, reduced the activity of this enzyme and abolished angiotensin II- and arachidonic acid-induced cell migration, [³H]thymidine and [³H]leucine incorporation. Metabolism of arachidonic acid to 5-, 12-, 15- and 20-hydoxyeicosatetraenoic acids in these cells was not altered, but angiotensin II- and arachidonic acid-induced reactive oxygen species production and extracellular signal-regulated kinase 1/2, and p38 mitogen-activated protein kinase, activity were inhibited by 2, 4, 3′, 5′-tetramethoxystilbene and cytochrome P450 1B1 shRNA, and by tempol that inactivates reactive oxygen species. Tempol did not alter cytochrome P450 1B1 activity. These data suggest that angiotensin II-induced vascular smooth muscle cell migration and growth are mediated by reactive oxygen species generated from arachidonic acid by cytochrome P450 1B1 and activation of extracellular signal-regulated kinase 1/2, and p38 mitogen-activated protein kinase.