RATIONALE: Voltage-dependent L-type (Ca(V)1.2) Ca(2+) channels are a heteromeric complex formed from pore-forming alpha(1) and auxiliary alpha(2)delta and beta subunits. Ca(V)1.2 channels are the principal Ca(2+) influx pathway in arterial myocytes and regulate multiple physiological functions, including contraction. The macromolecular composition of arterial myocyte Ca(V)1.2 channels remains poorly understood, with no studies having examined the molecular identity or physiological functions of alpha(2)delta subunits. OBJECTIVE: We investigated the functional significance of alpha(2)delta subunits in myocytes of resistance-size (100 to 200 mum diameter) cerebral arteries. METHODS AND RESULTS: alpha(2)delta-1 was the only alpha(2)delta isoform expressed in cerebral artery myocytes. Pregabalin, an alpha(2)delta-1/-2 ligand, and an alpha(2)delta-1 antibody, inhibited Ca(V)1.2 currents in isolated myocytes. Acute pregabalin application reversibly dilated pressurized arteries. Using a novel application of surface biotinylation, data indicated that >95% of Ca(V)1.2 alpha(1) and alpha(2)delta-1 subunits were present in the arterial myocyte plasma membrane. Alpha(2)delta-1 knockdown using short hairpin RNA reduced plasma membrane-localized Ca(V)1.2 alpha(1) subunits, caused a corresponding elevation in cytosolic Ca(V)1.2 alpha(1) subunits, decreased intracellular Ca(2+) concentration, inhibited pressure-induced vasoconstriction ("myogenic tone"), and attenuated pregabalin-induced vasodilation. Prolonged (24-hour) pregabalin exposure did not alter total alpha(2)delta-1 or Ca(V)1.2 alpha(1) proteins but decreased plasma membrane expression of each subunit, which reduced myogenic tone. CONCLUSIONS: alpha(2)delta-1 is essential for plasma membrane expression of arterial myocyte Ca(V)1.2 alpha(1) subunits. alpha(2)delta-1 targeting can block Ca(V)1.2 channels directly and inhibit surface expression of Ca(V)1.2 alpha(1) subunits, leading to vasodilation. These data identify alpha(2)delta-1 as a novel molecular target in arterial myocytes, the manipulation of which regulates contractility.
RATIONALE: Voltage-dependent L-type (Ca(V)1.2) Ca(2+) channels are a heteromeric complex formed from pore-forming alpha(1) and auxiliary alpha(2)delta and beta subunits. Ca(V)1.2 channels are the principal Ca(2+) influx pathway in arterial myocytes and regulate multiple physiological functions, including contraction. The macromolecular composition of arterial myocyte Ca(V)1.2 channels remains poorly understood, with no studies having examined the molecular identity or physiological functions of alpha(2)delta subunits. OBJECTIVE: We investigated the functional significance of alpha(2)delta subunits in myocytes of resistance-size (100 to 200 mum diameter) cerebral arteries. METHODS AND RESULTS: alpha(2)delta-1 was the only alpha(2)delta isoform expressed in cerebral artery myocytes. Pregabalin, an alpha(2)delta-1/-2 ligand, and an alpha(2)delta-1 antibody, inhibited Ca(V)1.2 currents in isolated myocytes. Acute pregabalin application reversibly dilated pressurized arteries. Using a novel application of surface biotinylation, data indicated that >95% of Ca(V)1.2 alpha(1) and alpha(2)delta-1 subunits were present in the arterial myocyte plasma membrane. Alpha(2)delta-1 knockdown using short hairpin RNA reduced plasma membrane-localized Ca(V)1.2 alpha(1) subunits, caused a corresponding elevation in cytosolic Ca(V)1.2 alpha(1) subunits, decreased intracellular Ca(2+) concentration, inhibited pressure-induced vasoconstriction ("myogenic tone"), and attenuated pregabalin-induced vasodilation. Prolonged (24-hour) pregabalin exposure did not alter total alpha(2)delta-1 or Ca(V)1.2 alpha(1) proteins but decreased plasma membrane expression of each subunit, which reduced myogenic tone. CONCLUSIONS: alpha(2)delta-1 is essential for plasma membrane expression of arterial myocyte Ca(V)1.2 alpha(1) subunits. alpha(2)delta-1 targeting can block Ca(V)1.2 channels directly and inhibit surface expression of Ca(V)1.2 alpha(1) subunits, leading to vasodilation. These data identify alpha(2)delta-1 as a novel molecular target in arterial myocytes, the manipulation of which regulates contractility.
Authors: M Dennis Leo; Simon Bulley; John P Bannister; Korah P Kuruvilla; Damodaran Narayanan; Jonathan H Jaggar Journal: Am J Physiol Cell Physiol Date: 2015-07-15 Impact factor: 4.249
Authors: Simon Bulley; Zachary P Neeb; Sarah K Burris; John P Bannister; Candice M Thomas-Gatewood; Wanchana Jangsangthong; Jonathan H Jaggar Journal: Circ Res Date: 2012-08-07 Impact factor: 17.367
Authors: John P Bannister; Candice M Thomas-Gatewood; Zachary P Neeb; Adebowale Adebiyi; Xiaoyang Cheng; Jonathan H Jaggar Journal: J Biol Chem Date: 2011-02-28 Impact factor: 5.157
Authors: Dianaly T Au; Zhekang Ying; Erick O Hernández-Ochoa; William E Fondrie; Brian Hampton; Mary Migliorini; Rebeca Galisteo; Martin F Schneider; Alan Daugherty; Debra L Rateri; Dudley K Strickland; Selen C Muratoglu Journal: Arterioscler Thromb Vasc Biol Date: 2018-11 Impact factor: 8.311