title: Transcriptional upregulation of α2δ-1 elevates arterial smooth muscle cell voltage-dependent Ca2+ channel surface expression and cerebrovascular constriction in genetic hypertension.
abstract: A hallmark of hypertension is an increase in arterial myocyte voltage-dependent Ca2+ (CaV1.2) currents that induces pathological vasoconstriction. CaV1.2 channels are heteromeric complexes composed of a pore-forming CaV1.2α1 with auxiliary α2δ and β subunits. Molecular mechanisms that elevate CaV1.2 currents during hypertension and the potential contribution of CaV1.2 auxiliary subunits are unclear. Here, we investigated the pathological significance of α2δ subunits in vasoconstriction associated with hypertension. Age-dependent development of hypertension in spontaneously hypertensive rats was associated with an unequal elevation in α2δ-1 and CaV1.2α1 mRNA and protein in cerebral artery myocytes, with α2δ-1 increasing more than CaV1.2α1. Other α2δ isoforms did not emerge in hypertension. Myocytes and arteries of hypertensive spontaneously hypertensive rats displayed higher surface-localized α2δ-1 and CaV1.2α1 proteins, surface α2δ-1:CaV1.2α1 ratio, CaV1.2 current density and noninactivating current, and pressure- and depolarization-induced vasoconstriction than those of Wistar-Kyoto controls. Pregabalin, an α2δ-1 ligand, did not alter α2δ-1 or CaV1.2α1 total protein but normalized α2δ-1 and CaV1.2α1 surface expression, surface α2δ-1:CaV1.2α1, CaV1.2 current density and inactivation, and vasoconstriction in myocytes and arteries of hypertensive rats to control levels. Genetic hypertension is associated with an elevation in α2δ-1 expression that promotes surface trafficking of CaV1.2 channels in cerebral artery myocytes. This leads to an increase in CaV1.2 current-density and a reduction in current inactivation that induces vasoconstriction. Data also suggest that α2δ-1 targeting is a novel strategy that may be used to reverse pathological CaV1.2 channel trafficking to induce cerebrovascular dilation in hypertension.
authors.affiliation: Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 894 Union Ave, Suite 426, Memphis, TN 38163, USA.
authors.forename: John P
authors.initials: JP
authors.lastname: Bannister
authors.forename: Simon
authors.initials: S
authors.lastname: Bulley
authors.forename: Damodaran
authors.initials: D
authors.lastname: Narayanan
authors.forename: Candice
authors.initials: C
authors.lastname: Thomas-Gatewood
authors.forename: Patrik
authors.initials: P
authors.lastname: Luzny
authors.forename: Judith
authors.initials: J
authors.lastname: Pachuau
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Jaggar
mesh_terms: D000818:Animals; D015220:Calcium Channels / Q000235:genetics* / Q000378:metabolism; D020746:Calcium Channels, L-Type / Q000235:genetics / Q000378:metabolism; D002536:Cerebral Arteries / Q000187:drug effects / Q000378:metabolism; D006973:Hypertension / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism; D000069583:Pregabalin; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics*; D014661:Vasoconstriction / Q000187:drug effects / Q000235:genetics*; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: C486060:Cacna2d1 protein, rat; D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D000069583:Pregabalin; D005680:gamma-Aminobutyric Acid