title: Potentiation of beta-adrenergic signaling by adenoviral-mediated gene transfer in adult rabbit ventricular myocytes.
abstract: Our laboratory has been testing the hypothesis that genetic modulation of the beta-adrenergic signaling cascade can enhance cardiac function. We have previously shown that transgenic mice with cardiac overexpression of either the human beta2-adrenergic receptor (beta2AR) or an inhibitor of the beta-adrenergic receptor kinase (betaARK), an enzyme that phosphorylates and uncouples agonist-bound receptors, have increased myocardial inotropy. We now have created recombinant adenoviruses encoding either the beta2AR (Adeno-beta2AR) or a peptide betaARK inhibitor (consisting of the carboxyl terminus of betaARK1, Adeno-betaARKct) and tested their ability to potentiate beta-adrenergic signaling in cultured adult rabbit ventricular myocytes. As assessed by radioligand binding, Adeno-beta2AR infection led to approximately 20-fold overexpression of beta-adrenergic receptors. Protein immunoblots demonstrated the presence of the Adeno-betaARKct transgene. Both transgenes significantly increased isoproterenol-stimulated cAMP as compared to myocytes infected with an adenovirus encoding beta-galactosidase (Adeno-betaGal) but did not affect the sarcolemmal adenylyl cyclase response to Forskolin or NaF. beta-Adrenergic agonist-induced desensitization was significantly inhibited in Adeno-betaARKct-infected myocytes (16+/-2%) as compared to Adeno-betaGal-infected myocytes (37+/-1%, P < 0.001). We conclude that recombinant adenoviral gene transfer of the beta2AR or an inhibitor of betaARK-mediated desensitization can potentiate beta-adrenergic signaling.
authors.affiliation: Howard Hughes Medical Institute, Department of Medicine (Cardiology), Duke University Medical Center, Durham, North Carolina 27710, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Drazner
authors.forename: K C
authors.initials: KC
authors.lastname: Peppel
authors.forename: S
authors.initials: S
authors.lastname: Dyer
authors.forename: A O
authors.initials: AO
authors.lastname: Grant
authors.forename: W J
authors.initials: WJ
authors.lastname: Koch
authors.forename: R J
authors.initials: RJ
authors.lastname: Lefkowitz
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000262:Adenylyl Cyclases / Q000032:analysis; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006352:Heart Ventricles / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D011817:Rabbits; D018343:Receptors, Adrenergic, beta-2 / Q000235:genetics* / Q000378:metabolism*; D012508:Sarcolemma / Q000201:enzymology; D015398:Signal Transduction; D019076:Transgenes
chemical_list: D000318:Adrenergic beta-Agonists; D018343:Receptors, Adrenergic, beta-2; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D007545:Isoproterenol