| Summary: | 碩士 === 長庚大學 === 生物醫學研究所 === 97 === 20-Hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P450 arachidonate metabolite, is a potent regulator of vascular function. Since VSMC migration is often associated with vascular wall remodeling in pathological status, we further asked whether 20-HETE inhibits migration of R22D cells. With both wound-healing assay and Transwell assay, we demonstrated that 20-HETE significantly attenuated migration induced by platelet-derived growth factor (PDGF) in a concentration-dependent manner in R22D cells. However, serum-induced migration of endothelial cells was not affected by up to 1 M of 20-HETE. Incubation of 20-HETE (10 nM) for 6 hr attenuated PDGF-induced Transwell migration by approximately 30%, which was reversed by SQ22536, an adenylyl cyclase inhibitor, or H89, a protein kinase A (PKA) inhibitor, suggesting involvement of cAMP/PKA pathway in the inhibitory effects of 20-HETE. Incubation of 8-bromo cAMP for 6 hr also attenuated PDGF-induced cell migration in a concentration-dependent manner. However 20-HETE did not alter levels of cAMP or phosphorylated focal adhesion kinase in R22D cells. Nevertheless, 20-HETE significantly enhanced the PKA activity. In addition, pretreatment of 20-HETE partially disrupted F-actin reorganization induced by PDGF, which was reversed by SQ22536. These results suggest that 20-HETE may inhibit PDGF-induced VSMC migration via sensitization of the cAMP/PKA pathway and consequently interfere F-actin reorganization.
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