Inhibition of vascular smooth muscle G protein-coupled receptor kinase 2 enhances alpha1D-adrenergic receptor constriction.
G protein-coupled receptor kinase 2 (GRK2) is a serine/theorinine kinase that phosphorylates and desensitizes agonist-bound G protein-coupled receptors. GRK2 is increased in expression and activity in lymphocytes and vascular smooth muscle (VSM) in human hypertension and animal models of the disease. Inhibition of GRK2 using the carboxyl-terminal portion of the protein (GRK2ct) has been an effective tool to restore compromised beta-adrenergic receptor (AR) function in heart failure and improve outcome. A well-characterized dysfunction in hypertension is attenuation of betaAR-mediated vasodilation. Therefore, we tested the role of inhibition of GRK2 using GRK2ct or VSM-selective GRK2 gene ablation in a renal artery stenosis model of elevated blood pressure (BP) [the two-kidney, one-clip (2K1C) model]. Use of the 2K1C model resulted in a 30% increase in conscious BP, a threefold increase in plasma norepinephrine levels, and a 50% increase in VSM GRK2 mRNA levels. BP remained increased despite VSM-specific GRK2 inhibition by either GRK2 knockout (GRK2KO) or peptide inhibition (GRK2ct). Although betaAR-mediated dilation in vivo and in situ was enhanced, alpha(1)AR-mediated vasoconstriction was also increased. Further pharmacological experiments using alpha(1)AR antagonists revealed that GRK2 inhibition of expression (GRK2KO) or activity (GRK2ct) enhanced alpha(1D)AR vasoconstriction. This is the first study to suggest that VSM alpha(1D)ARs are a GRK2 substrate in vivo.
Cohn
Heather Irina
HI
Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
Harris
David M
DM
Pesant
Stephanie
S
Pfeiffer
Michael
M
Zhou
Rui-Hai
RH
Koch
Walter J
WJ
Dorn
Gerald W
GW
Eckhart
Andrea D
AD
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000201:enzymology; D001794:Blood Pressure; D002417:Cattle; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D054769:G-Protein-Coupled Receptor Kinase 2 / Q000235:genetics / Q000378:metabolism*; D006978:Hypertension, Renovascular / Q000201:enzymology* / Q000209:etiology / Q000503:physiopathology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology*; D009638:Norepinephrine / Q000097:blood; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects / Q000378:metabolism*; D012078:Renal Artery Obstruction / Q000150:complications* / Q000201:enzymology / Q000503:physiopathology; D014661:Vasoconstriction / Q000187:drug effects
C547716:ADRA1B protein, human; C547719:ADRA1D protein, human; C547717:Adra1b protein, mouse; C547720:Adra1d protein, mouse; D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D018340:Receptors, Adrenergic, alpha-1; D000804:Angiotensin II; C496568:GRK2 protein, mouse; D054769:G-Protein-Coupled Receptor Kinase 2; D009638:Norepinephrine