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Völkers M, Weidenhammer C, Herzog N, Qiu G, Spaich K, Wegner FV, Peppel K, Müller OJ, Schinkel S, Rabinowitz JE, Hippe HJ, Brinks H, Katus HA, Koch WJ, Eckhart AD, Friedrich O, Most P. The inotropic peptide βARKct improves βAR responsiveness in normal and failing cardiomyocytes through G(βγ)-mediated L-type calcium current disinhibition. Circ Res 2011; 108:27-39. [PMID: 21106943 PMCID: PMC4013502 DOI: 10.1161/circresaha.110.225201] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Accepted: 11/15/2010] [Indexed: 12/20/2022]
Abstract
RATIONALE The G(βγ)-sequestering peptide β-adrenergic receptor kinase (βARK)ct derived from the G-protein-coupled receptor kinase (GRK)2 carboxyl terminus has emerged as a promising target for gene-based heart failure therapy. Enhanced downstream cAMP signaling has been proposed as the underlying mechanism for increased β-adrenergic receptor (βAR) responsiveness. However, molecular targets mediating improved cardiac contractile performance by βARKct and its impact on G(βγ)-mediated signaling have yet to be fully elucidated. OBJECTIVE We sought to identify G(βγ)-regulated targets and signaling mechanisms conveying βARKct-mediated enhanced βAR responsiveness in normal (NC) and failing (FC) adult rat ventricular cardiomyocytes. METHODS AND RESULTS Assessing viral-based βARKct gene delivery with electrophysiological techniques, analysis of contractile performance, subcellular Ca²(+) handling, and site-specific protein phosphorylation, we demonstrate that βARKct enhances the cardiac L-type Ca²(+) channel (LCC) current (I(Ca)) both in NCs and FCs on βAR stimulation. Mechanistically, βARKct augments I(Ca) by preventing enhanced inhibitory interaction between the α1-LCC subunit (Cav1.2α) and liberated G(βγ) subunits downstream of activated βARs. Despite improved βAR contractile responsiveness, βARKct neither increased nor restored cAMP-dependent protein kinase (PKA) and calmodulin-dependent kinase II signaling including unchanged protein kinase (PK)Cε, extracellular signal-regulated kinase (ERK)1/2, Akt, ERK5, and p38 activation both in NCs and FCs. Accordingly, although βARKct significantly increases I(Ca) and Ca²(+) transients, being susceptible to suppression by recombinant G(βγ) protein and use-dependent LCC blocker, βARKct-expressing cardiomyocytes exhibit equal basal and βAR-stimulated sarcoplasmic reticulum Ca²(+) load, spontaneous diastolic Ca²(+) leakage, and survival rates and were less susceptible to field-stimulated Ca²(+) waves compared with controls. CONCLUSION Our study identifies a G(βγ)-dependent signaling pathway attenuating cardiomyocyte I(Ca) on βAR as molecular target for the G(βγ)-sequestering peptide βARKct. Targeted interruption of this inhibitory signaling pathway by βARKct confers improved βAR contractile responsiveness through increased I(Ca) without enhancing regular or restoring abnormal cAMP-signaling. βARKct-mediated improvement of I(Ca) rendered cardiomyocytes neither susceptible to βAR-induced damage nor arrhythmogenic sarcoplasmic reticulum Ca²(+) leakage.
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Affiliation(s)
- Mirko Völkers
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Christian Weidenhammer
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Nicole Herzog
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Gang Qiu
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Kristin Spaich
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Frederic V Wegner
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Karsten Peppel
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Oliver J Müller
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Stefanie Schinkel
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Joseph E Rabinowitz
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Hans-Jorg Hippe
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Henriette Brinks
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Hugo A Katus
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Walter J Koch
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Andrea D Eckhart
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Oliver Friedrich
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
| | - Patrick Most
- Center for Molecular and Translational Cardiology (M.V, C.W., N.H., K.S., P.M.), Department of Internal Medicine III (O.J.M, S.S., H.J.H., H.A.K.), Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany; Institute of Physiology and Pathophysiology (F.W., O.F.) Medical Biophysics, INF 326, University of Heidelberg, 69120 Heidelberg, Germany; George Zallie & Family Laboratory for Cardiovascular Gene Therapy (J.E.R., H.B., W.J.K.), Eugene Feiner Laboratory for Vascular Biology and Thrombosis (A.D.E.), Laboratory for Cardiac Stem Cell and Gene Therapy (G.Q., K.P., P.M.), Center for Translational Medicine, Thomas Jefferson University, 19107 Philadelphia, PA, USA
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