TY - JOUR
T1 - Peptidomimetic Targeting of Cavβ2 Overcomes Dysregulation of the L-Type Calcium Channel Density and Recovers Cardiac Function
AU - Rusconi, Francesca
AU - Ceriotti, Paola
AU - Miragoli, Michele
AU - Carullo, Pierluigi
AU - Salvarani, Nicolò
AU - Rocchetti, Marcella
AU - Di Pasquale, Elisa
AU - Rossi, Stefano
AU - Tessari, Maddalena
AU - Caprari, Silvia
AU - Cazade, Magali
AU - Kunderfranco, Paolo
AU - Chemin, Jean
AU - Bang, Marie Louise
AU - Polticelli, Fabio
AU - Zaza, Antonio
AU - Faggian, Giuseppe
AU - Condorelli, Gianluigi
AU - Catalucci, Daniele
PY - 2016/8/16
Y1 - 2016/8/16
N2 - Background: L-type calcium channels (LTCCs) play important roles in regulating cardiomyocyte physiology, which is governed by appropriate LTCC trafficking to and density at the cell surface. Factors influencing the expression, half-life, subcellular trafficking, and gating of LTCCs are therefore critically involved in conditions of cardiac physiology and disease. Methods: Yeast 2-hybrid screenings, biochemical and molecular evaluations, protein interaction assays, fluorescence microscopy, structural molecular modeling, and functional studies were used to investigate the molecular mechanisms through which the LTCC Cavβ2 chaperone regulates channel density at the plasma membrane. Results: On the basis of our previous results, we found a direct linear correlation between the total amount of the LTCC pore-forming Cav1.2 and the Akt-dependent phosphorylation status of Cavβ2 both in a mouse model of diabetic cardiac disease and in 6 diabetic and 7 nondiabetic cardiomyopathy patients with aortic stenosis undergoing aortic valve replacement. Mechanistically, we demonstrate that a conformational change in Cavβ2 triggered by Akt phosphorylation increases LTCC density at the cardiac plasma membrane, and thus the inward calcium current, through a complex pathway involving reduction of Cav1.2 retrograde trafficking and protein degradation through the prevention of dynamin-mediated LTCC endocytosis; promotion of Cav1.2 anterograde trafficking by blocking Kir/Gem-dependent sequestration of Cavβ2, thus facilitating the chaperoning of Cav1.2; and promotion of Cav1.2 transcription by the prevention of Kir/Gem-mediated shuttling of Cavβ2 to the nucleus, where it limits the transcription of Cav1.2 through recruitment of the heterochromatin protein 1γ epigenetic repressor to the Cacna1c promoter. On the basis of this mechanism, we developed a novel mimetic peptide that, through targeting of Cavβ2, corrects LTCC life-cycle alterations, facilitating the proper function of cardiac cells. Delivery of mimetic peptide into a mouse model of diabetic cardiac disease associated with LTCC abnormalities restored impaired calcium balance and recovered cardiac function. Conclusions: We have uncovered novel mechanisms modulating LTCC trafficking and life cycle and provide proof of concept for the use of Cavβ2 mimetic peptide as a novel therapeutic tool for the improvement of cardiac conditions correlated with alterations in LTCC levels and function.
AB - Background: L-type calcium channels (LTCCs) play important roles in regulating cardiomyocyte physiology, which is governed by appropriate LTCC trafficking to and density at the cell surface. Factors influencing the expression, half-life, subcellular trafficking, and gating of LTCCs are therefore critically involved in conditions of cardiac physiology and disease. Methods: Yeast 2-hybrid screenings, biochemical and molecular evaluations, protein interaction assays, fluorescence microscopy, structural molecular modeling, and functional studies were used to investigate the molecular mechanisms through which the LTCC Cavβ2 chaperone regulates channel density at the plasma membrane. Results: On the basis of our previous results, we found a direct linear correlation between the total amount of the LTCC pore-forming Cav1.2 and the Akt-dependent phosphorylation status of Cavβ2 both in a mouse model of diabetic cardiac disease and in 6 diabetic and 7 nondiabetic cardiomyopathy patients with aortic stenosis undergoing aortic valve replacement. Mechanistically, we demonstrate that a conformational change in Cavβ2 triggered by Akt phosphorylation increases LTCC density at the cardiac plasma membrane, and thus the inward calcium current, through a complex pathway involving reduction of Cav1.2 retrograde trafficking and protein degradation through the prevention of dynamin-mediated LTCC endocytosis; promotion of Cav1.2 anterograde trafficking by blocking Kir/Gem-dependent sequestration of Cavβ2, thus facilitating the chaperoning of Cav1.2; and promotion of Cav1.2 transcription by the prevention of Kir/Gem-mediated shuttling of Cavβ2 to the nucleus, where it limits the transcription of Cav1.2 through recruitment of the heterochromatin protein 1γ epigenetic repressor to the Cacna1c promoter. On the basis of this mechanism, we developed a novel mimetic peptide that, through targeting of Cavβ2, corrects LTCC life-cycle alterations, facilitating the proper function of cardiac cells. Delivery of mimetic peptide into a mouse model of diabetic cardiac disease associated with LTCC abnormalities restored impaired calcium balance and recovered cardiac function. Conclusions: We have uncovered novel mechanisms modulating LTCC trafficking and life cycle and provide proof of concept for the use of Cavβ2 mimetic peptide as a novel therapeutic tool for the improvement of cardiac conditions correlated with alterations in LTCC levels and function.
KW - calcium
KW - calcium channels, L-type
KW - cardiovascular diseases
KW - diabetic cardiomyopathies
KW - drug therapy
KW - peptides
KW - protein transport
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U2 - 10.1161/CIRCULATIONAHA.116.021347
DO - 10.1161/CIRCULATIONAHA.116.021347
M3 - Article
AN - SCOPUS:84981244026
VL - 134
SP - 534
EP - 546
JO - Circulation
JF - Circulation
SN - 0009-7322
IS - 7
ER -