title: Peptidomimetic Targeting of Cavβ2 Overcomes Dysregulation of the L-Type Calcium Channel Density and Recovers Cardiac Function.
abstract: 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.
  
  
  
  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.
  
  
  
  On the basis of our previous results, we found a direct linear correlation between the total amount of the LTCC pore-forming Cavα1.2 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 Cavα1.2 retrograde trafficking and protein degradation through the prevention of dynamin-mediated LTCC endocytosis; promotion of Cavα1.2 anterograde trafficking by blocking Kir/Gem-dependent sequestration of Cavβ2, thus facilitating the chaperoning of Cavα1.2; and promotion of Cavα1.2 transcription by the prevention of Kir/Gem-mediated shuttling of Cavβ2 to the nucleus, where it limits the transcription of Cavα1.2 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.
  
  
  
  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.
authors.affiliation: From Humanitas Clinical and Research Center, Rozzano, Milan, Italy (F.R., P. Ceriotti, M.M., P. Carullo, N.S., E.D.P., P.K., M.-L.B., G.C., D.C.); Institute of Genetic and Biomedical Research UOS Milan National Research Council, Milan, Italy (F.R., P. Carullo, N.S., E.D.P., M.-L.B., D.C.); Department of Biotechnologies and Biosciences, University of Milan-Bicocca, Milan, Italy (M.R., A.Z.); Departments of Life Sciences (S.R.) and Clinical and Experimental Medicine (M.M.), University of Parma, Parma, Italy; University Hospital of Verona, Division of Cardiac Surgery, Verona, Italy (M.T., G.F.); Department of Sciences, University of Roma Tre, Rome, Italy (S.C., F.P.); University of Montpellier, CNRS UMR 5203, INSERM, Department of Neuroscience, Institute for Functional Genomics, LabEx Ion Channel Science and Therapeutics, Montpellier, France (M.C., J.C.); and National Institute of Nuclear Physics, Rome Tre Section, Rome, Italy (F.P.).
authors.forename: Francesca
authors.initials: F
authors.lastname: Rusconi
authors.affiliation: From Humanitas Clinical and Research Center, Rozzano, Milan, Italy (F.R., P. Ceriotti, M.M., P. Carullo, N.S., E.D.P., P.K., M.-L.B., G.C., D.C.); Institute of Genetic and Biomedical Research UOS Milan National Research Council, Milan, Italy (F.R., P. Carullo, N.S., E.D.P., M.-L.B., D.C.); Department of Biotechnologies and Biosciences, University of Milan-Bicocca, Milan, Italy (M.R., A.Z.); Departments of Life Sciences (S.R.) and Clinical and Experimental Medicine (M.M.), University of Parma, Parma, Italy; University Hospital of Verona, Division of Cardiac Surgery, Verona, Italy (M.T., G.F.); Department of Sciences, University of Roma Tre, Rome, Italy (S.C., F.P.); University of Montpellier, CNRS UMR 5203, INSERM, Department of Neuroscience, Institute for Functional Genomics, LabEx Ion Channel Science and Therapeutics, Montpellier, France (M.C., J.C.); and National Institute of Nuclear Physics, Rome Tre Section, Rome, Italy (F.P.).
authors.forename: Paola
authors.initials: P
authors.lastname: Ceriotti
authors.forename: Michele
authors.initials: M
authors.lastname: Miragoli
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Carullo
authors.forename: Nicolò
authors.initials: N
authors.lastname: Salvarani
authors.forename: Marcella
authors.initials: M
authors.lastname: Rocchetti
authors.forename: Elisa
authors.initials: E
authors.lastname: Di Pasquale
authors.forename: Stefano
authors.initials: S
authors.lastname: Rossi
authors.forename: Maddalena
authors.initials: M
authors.lastname: Tessari
authors.forename: Silvia
authors.initials: S
authors.lastname: Caprari
authors.forename: Magali
authors.initials: M
authors.lastname: Cazade
authors.forename: Paolo
authors.initials: P
authors.lastname: Kunderfranco
authors.forename: Jean
authors.initials: J
authors.lastname: Chemin
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Bang
authors.forename: Fabio
authors.initials: F
authors.lastname: Polticelli
authors.forename: Antonio
authors.initials: A
authors.lastname: Zaza
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Faggian
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Condorelli
authors.forename: Daniele
authors.initials: D
authors.lastname: Catalucci
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D040761:Biomimetic Materials / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000235:genetics / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000188:drug therapy / Q000378:metabolism; D002478:Cells, Cultured; D016503:Drug Delivery Systems / Q000379:methods*; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism; D057786:Peptidomimetics / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012189:Retrospective Studies
chemical_list: C491528:Cacnb2 protein, mouse; D020746:Calcium Channels, L-Type; D057786:Peptidomimetics
keywords: calcium; calcium channels, L-type; cardiovascular diseases; diabetic cardiomyopathies; drug therapy; peptides; protein transport