title: Bi-phasic activation of eNOS in response to uni-axial cyclic stretch is mediated by differential mechanisms in BAECs.
abstract: We investigated the signaling mechanism of stretch-induced NO (Nitric oxide) production in bovine arterial endothelial cells (BAECs). BAECs cultured on an elastic silicone chamber coated with fibronectin were subjected to uni-axial cyclic stretch (1 Hz, 20% in length) and the amount of produced NO was measured by a cGMP assay. NO production increased in a bi-phasic manner and peaked at 5 min and 20 min after stretch onset. Correspondingly, the activities of endothelial nitric oxide synthase (eNOS) and Akt/PKB (measured by phosphorylation at serine 1,177 and serine 473, respectively), showed two peaks over time. Application of Gd(3+), a potent SA channel blocker, and depletion of external Ca(2+) exclusively inhibited the first peaks of eNOS and Akt activity, but exerted little effect on the second peak. On the other hand, the PI3K inhibitors, Wortmannin, LY294002, almost completely inhibited the second peak but not the first. These results suggest that up-regulation of eNOS in response to cyclic stretch was mediated by two distinct pathways, [Ca(2+)](i) increases via the SA channel in an early phase (partially Akt/PKB), and PI3K-Akt/PKB pathways in a late phase.
authors.affiliation: Division of Vascular Surgery, Department of Surgery, Nagoya 466-8550, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Takeda
authors.forename: Kimihiro
authors.initials: K
authors.lastname: Komori
authors.forename: Naomichi
authors.initials: N
authors.lastname: Nishikimi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nimura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sokabe
authors.forename: Keiji
authors.initials: K
authors.lastname: Naruse
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D002867:Chromones / Q000494:pharmacology; D042783:Endothelial Cells / Q000201:enzymology* / Q000502:physiology; D004789:Enzyme Activation; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D033081:Shear Strength; D015398:Signal Transduction; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D002118:Calcium; D002867:Chromones; D051036:Large-Conductance Calcium-Activated Potassium Channels; D009025:Morpholines; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D012694:Serine; D000077191:Wortmannin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one