title: Desmoglein-2 interaction is crucial for cardiomyocyte cohesion and function.
abstract: OBJECTIVE
  We determined the contribution of the desmosomal cadherin desmoglein-2 to cell-cell cohesion in cardiomyocytes. In the intercalated disc, providing mechanical strength and electrical communication between adjacent cardiomyocytes, desmoglein-2 is closely associated with N-cadherin and gap junctions.
  
  
  RESULTS
  We studied intercalated discs of HL-1 cardiomyocytes by immunostaining of desmoglein-2 and N-cadherin. Cohesion was measured using a liberase-based dissociation-assay and compared with cell-free single-molecule atomic force microscopy measurements. L-tryptophan caused irregular desmoglein-2 condensation, weakened cell-cell cohesion and impaired both homophilic desmoglein-2 and N-cadherin trans-interaction, whereas l-phenylalanine had no effect. L-tryptophan did not affect N-cadherin localization and its inhibitory effect on cell-cohesion and desmoglein-2 binding, but not on N-cadherin interaction, was blocked by a desmoglein-specific tandem peptide. Moreover, Ca(2+)-depletion, desmoglein-2 knockdown, a desmoglein-specific single peptide and certain desmoglein-2 mutations associated with arrhythmogenic cardiomyopathy reduced cell-cell cohesion, whereas cell adhesion was strengthened by desmoglein-2 overexpression. Since single peptide did not interfere with N-cadherin trans-interaction, these data indicate that (i) desmoglein-2 binding is crucial for cardiomyocyte cohesion and (ii) L-tryptophan reduced both desmoglein-2 and N-cadherin binding, whereas single and tandem peptide can be used to specifically target desmoglein-2-mediated adhesion. L-tryptophan and single peptide also induced ultrastructural alterations of areae compositae. Functional analyses at the organ level revealed reduced cardiomyocyte function and inefficient response to adrenergic stimulation in both L-tryptophan- and single peptide-challenged murine Langendorff hearts paralleled by redistribution of connexin 43 in L-tryptophan-treated heart slices.
  
  
  CONCLUSIONS
  Our data demonstrate that desmoglein-2 plays a critical role in cardiomyocyte cohesion and function.
authors.affiliation: Institute of Anatomy and Cell Biology, Ludwig-Maximilians Universität Munich, Pettenkofer Str. 11, Munich 80336, Germany.
authors.forename: Angela
authors.initials: A
authors.lastname: Schlipp
authors.affiliation: Institute of Anatomy and Cell Biology, Ludwig-Maximilians Universität Munich, Pettenkofer Str. 11, Munich 80336, Germany.
authors.forename: Camilla
authors.initials: C
authors.lastname: Schinner
authors.affiliation: Institute of Anatomy and Cell Biology, Ludwig-Maximilians Universität Munich, Pettenkofer Str. 11, Munich 80336, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Spindler
authors.affiliation: Institute of Anatomy and Cell Biology, Ludwig-Maximilians Universität Munich, Pettenkofer Str. 11, Munich 80336, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Vielmuth
authors.affiliation: Department of Cardiovascular Medicine, University of Oxford, Oxford, UK.
authors.forename: Katja
authors.initials: K
authors.lastname: Gehmlich
authors.affiliation: Institute of Cardiovascular Science, University College London, London, UK.
authors.forename: Petros
authors.initials: P
authors.lastname: Syrris
authors.affiliation: Institute of Cardiovascular Science, University College London, London, UK.
authors.forename: William J
authors.initials: WJ
authors.lastname: Mckenna
authors.affiliation: Walter-Brendel-Center of Experimental Medicine, Ludwig-Maximilians Universität Munich, Munich, Germany Munich Heart Alliance, Munich, Germany German Center for Cardiovascular Research, Munich, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Dendorfer
authors.affiliation: Institute of Anatomy and Cell Biology, Ludwig-Maximilians Universität Munich, Pettenkofer Str. 11, Munich 80336, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Hartlieb
authors.affiliation: Institute of Anatomy and Cell Biology, Ludwig-Maximilians Universität Munich, Pettenkofer Str. 11, Munich 80336, Germany jens.waschke@med.uni-muenchen.de.
authors.forename: Jens
authors.initials: J
authors.lastname: Waschke
mesh_terms: D000818:Animals; D015820:Cadherins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D018031:Connexin 43 / Q000378:metabolism; D051301:Desmoglein 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D017629:Gap Junctions / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D000067268:Isolated Heart Preparation; D008807:Mice, Inbred BALB C; D009154:Mutation; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D010455:Peptides / Q000494:pharmacology; D018342:Receptors, Adrenergic, beta-1 / Q000378:metabolism; D015398:Signal Transduction; D014364:Tryptophan / Q000494:pharmacology
chemical_list: D015820:Cadherins; C489083:Cdh2 protein, mouse; D018031:Connexin 43; D051301:Desmoglein 2; C495315:Dsg2 protein, mouse; C543076:GJA1 protein, mouse; D010455:Peptides; D018342:Receptors, Adrenergic, beta-1; D014364:Tryptophan; D002118:Calcium
keywords: Arrhythmogenic cardiomyopathy; Cardiomyocyte cohesion; Desmoglein-2; Desmosome; Langendorff