title: Gene therapy to inhibit the calcium channel beta subunit: physiological consequences and pathophysiological effects in models of cardiac hypertrophy.
abstract: Calcium cycling figures prominently in excitation-contraction coupling and in various signaling cascades involved in the development of left ventricular hypertrophy. We hypothesized that genetic suppression of the L-type calcium channel accessory beta-subunit would modulate calcium current and suppress cardiac hypertrophy. A short hairpin RNA template sequence capable of mediating the knockdown of the L-type calcium channel accessory beta-subunit gene was incorporated into a lentiviral vector (PPT.CG.H1.beta(2)). Transduction of ventricular myocytes in vivo with the active short hairpin RNA partially inhibited the L-type calcium current. In neonatal rat cardiomyocytes, L-type calcium channel accessory beta-subunit gene knockdown reduced calcium transient amplitude. Similarly, [(3)H]leucine incorporation was attenuated in PPT.CG.H1.beta(2)-transduced neonatal rat cardiomyocytes compared with nonsilencing controls in a phenylephrine-induced hypertrophy model. In vivo gene transfer attenuated the hypertrophic response in an aortic-banded rat model of left ventricular hypertrophy, with reduced left ventricular wall thickness and heart weight/body weight ratios in PPT.CG.H1.beta(2)-injected rats at four weeks post transduction. Fractional shortening was preserved in rats treated with PPT.CG.H1.beta(2). These findings indicate that knockdown of L-type calcium channel accessory beta-subunit is capable of attenuating the hypertrophic response both in vitro and in vivo without compromising systolic performance. Suppression of the calcium channel beta subunit may represent a novel and useful therapeutic strategy for left ventricular hypertrophy.
authors.affiliation: Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Cingolani
authors.forename: Genaro A
authors.initials: GA
authors.lastname: Ramirez Correa
authors.forename: Eddy
authors.initials: E
authors.lastname: Kizana
authors.forename: Mitsushige
authors.initials: M
authors.lastname: Murata
authors.forename: Hee Cheol
authors.initials: HC
authors.lastname: Cho
authors.forename: Eduardo
authors.initials: E
authors.lastname: Marbán
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D020746:Calcium Channels, L-Type / Q000172:deficiency* / Q000378:metabolism*; D004195:Disease Models, Animal; D020868:Gene Silencing; D015316:Genetic Therapy; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D016086:Lentivirus; D032383:Myocytes, Cardiac / Q000378:metabolism* / Q000473:pathology; D009929:Organ Size / Q000235:genetics; D021122:Protein Subunits / Q000172:deficiency / Q000378:metabolism; D051381:Rats; D014161:Transduction, Genetic
chemical_list: D020746:Calcium Channels, L-Type; D021122:Protein Subunits