title: AMPK alpha 1-induced RhoA phosphorylation mediates vasoprotective effect of estradiol.
abstract: OBJECTIVE
  Estradiol (E2) mediates numerous beneficial effects assigned to estrogens, but whereas mechanisms have been described at the endothelial level, direct effects on vascular smooth muscle cells (VSMC) are poorly documented. As evidence accumulates regarding the role of RhoA in vascular pathophysiology and the benefit of RhoA-Rho associated protein kinase (Rock) pathway inhibition, we analyzed if E2 could inhibit it in VSMC.
  
  
  RESULTS
  We show that in VSMC, E2 inhibits the RhoA-Rock pathway in a time- and concentration-dependent manner. The inhibition of RhoA-Rock pathway results from E2-induced phosphorylation of the Ser188 of RhoA. Using pharmacological, transfection, and in vitro phosphorylation experiments, we demonstrate that AMP-activated protein kinase subunit alpha 1 (AMPKα1) is activated by estrogen receptor stimulation and catalyzes RhoA phosphorylation induced by E2. Ex vivo, ovariectomy leads to an increase in the amplitude of phenylephrine- or serotonine-induced contractions of aortic rings in wild-type mice but not in AMPKα1-knock-out mice or E2-supplemented animals. These functional effects were correlated with a reduced level of RhoA phosphorylation in the aorta of ovariectomized female, male, and AMPKα1 knock-out mice.
  
  
  CONCLUSIONS
  Our work thus defines AMPKα1 as (1) a new kinase for RhoA and (2) a new mediator of the vasoprotective effects of estrogen.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, UMR915, Institut du Thorax, Nantes, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Gayard
authors.forename: Christophe
authors.initials: C
authors.lastname: Guilluy
authors.forename: Anthony
authors.initials: A
authors.lastname: Rousselle
authors.forename: Benoit
authors.initials: B
authors.lastname: Viollet
authors.forename: Daniel
authors.initials: D
authors.lastname: Henrion
authors.forename: Pierre
authors.initials: P
authors.lastname: Pacaud
authors.forename: Gervaise
authors.initials: G
authors.lastname: Loirand
authors.forename: Malvyne
authors.initials: M
authors.lastname: Rolli-Derkinderen
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D023421:Models, Animal; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D010052:Ovariectomy; D010766:Phosphorylation / Q000187:drug effects; D011960:Receptors, Estrogen / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014661:Vasoconstriction / Q000502:physiology; D020741:rho GTP-Binding Proteins / Q000378:metabolism*; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020742:rhoA GTP-Binding Protein
chemical_list: D011960:Receptors, Estrogen; D004958:Estradiol; C548179:Prkaa1 protein, mouse; D054460:rho-Associated Kinases; D055372:AMP-Activated Protein Kinases; C526380:RhoA protein, mouse; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein