Adeno-associated virus-mediated transfer of endothelial nitric oxide synthase gene inhibits protein synthesis of rat ventricular cardiomyocytes

We investigated whether nitric oxide (NO) synthase gene transfer could atte nuate growth of cultured cardiac myocytes. First, we investigated the effec ts of exogenous NO and cGMP analog on protein synthesis of cultured neonata l rat cardiac myocytes. The NO donor 3-morpholino-sydnonimine-hydrochloride (SIN-1) and 8-bromo-cGMP caused concentration-dependent decreases in pheny lephrine-stimulated incorporation of H-3-leucine into cardiac myocytes. We then transferred endothelial constitutive NO synthase (ecNOS) gene into cul tured neonatal rat cardiac myocytes using adeno-associated virus (AAV) vect ors. ecNOS gene transfer into cardiac myocytes induced 140 kD ecNOS protein expression and significantly increased cGMP contents of myocytes compared with control cells. ecNOS gene transfer inhibited H-3-leucine incorporation into cardiac myocytes in response to phenylephrine, which was significantl y recovered in the presence of the NOS inhibitor N-G-monomethyl-L-arginine acetate. These results indicate that endogenously generated NO by ecNOS gen e transfer using AAV vectors inhibits the alpha -adrenergic agonist-induced cardiac protein synthesis at least partially via cGMP production.