title: Shear stress activates extracellular signal-regulated kinase 1/2 via the angiotensin II type 1 receptor.
abstract: Mechanical factors such as strain, pressure, and shear stress are key regulators of cell function, but the molecular mechanisms underlying the detection and responses to such stimuli are poorly understood. Whether the angiotensin II (AngII) AT1 receptor (AT1R) transduces shear stress in endothelial cells (ECs) is unknown. We exposed human umbilical cord endothelial cells (HUVECs) to a shear stress of 0 (control) or 15 dyn/cm(2) for 5 or 10 min. The colocalization of AT1R with caveolin-1 (Cav1), endosomal markers Rab5, EEA1, and Rab7, and lysosomal marker Lamp-1 increased in shear stimulated cells, detected by immunocytochemistry. Shear stress reduced labeling of wild-type mouse ECs (18±3% of unsheared control, P<0.01) but not Cav1(-/-) ECs (90±10%) with fluorescent AngII, confirming that internalization of AT1R requires Cav1. Shear stress activated ERK1/2 2-fold (P<0.01), which was prevented by the AT1R blocker losartan. NADPH oxidase inhibition with apocynin prevented both the colocalization of AT1R with Cav1 and the induction of ERK1/2 by shear stress. Moreover, shear-dependent ERK1/2 activation was minimal in CHO cells expressing an AT1Ra mutant that does not internalize, compared with cells expressing wild-type AT1Ra (P<0.05). Hence, AT1R may be an important transducer of shear stress-dependent activation of ERK1/2.
authors.affiliation: Paris Cardiovascular Research Center, Paris, France.
authors.forename: Bhama
authors.initials: B
authors.lastname: Ramkhelawon
authors.forename: Daniel
authors.initials: D
authors.lastname: Rivas
authors.forename: Stephanie
authors.initials: S
authors.lastname: Lehoux
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D000818:Animals; D016466:CHO Cells; D051242:Caveolin 1 / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D019808:Losartan / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D034622:RNA Interference; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism*; D013314:Stress, Mechanical
chemical_list: D000098:Acetophenones; D047228:Angiotensin II Type 1 Receptor Blockers; C495541:Cav1 protein, mouse; D051242:Caveolin 1; D004791:Enzyme Inhibitors; D044140:Receptor, Angiotensin, Type 1; D000804:Angiotensin II; C056165:acetovanillone; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D019808:Losartan
keywords: caveolin-1; endosomes; endothelial cells; mechanotransduction; receptor internalization