title: Structural adaptation in adult rabbit ventricular myocytes: influence of dynamic physical interaction with fibroblasts.
abstract: The mechanism of induction of cardiomyocyte (CM) dedifferentiation, as seen in chronic hibernating myocardium, is largely unknown. Recently, a cellular model was proposed consisting of long-term cocultures of adult rabbit CMs and cardiac fibroblasts in which typical structural characteristics of hibernation-like dedifferentiation could be induced. Only CMs in close contact with fibroblasts underwent these changes. In this study, we further investigated the characteristics of the fibroblast-CM interaction to seek for triggers and phenomena involved in CM dedifferentiation. Adult rabbit CMs were cocultured with cardiac or 3T3 fibroblasts. Heterocellular interactions and the structural adaptation of the CMs were quantified and studied with vital microscopy and electron microscopy. Immunocytochemical analysis of several adhesion molecules, i.e., N-cadherin, vinculin, beta1-integrin, and desmoplakin, were examined. Upon contact with CMs, fibroblasts attached firmly and pulled the former cells, resulting in anisotropic stretch. Quantification of the attachment sites revealed a predominant binding of the fibroblast to the distal ends of the CM in d 1 cocultures and a shift towards the lateral sides of the CMs on d 2 of coculture, suggesting a redistribution of CM membrane proteins. Immunocytochemical analysis of cell adhesion proteins showed that these were upregulated at the heterocellular contact sites. Addition of autologous and nonautologous fibroblasts to the CM culture similarly induced a progressive and accelerated structural adaptation of the CM. Dynamic passive stretch invoked by the fibroblasts and/or intercellular communication involving cell adhesion molecule expression at the interaction sites may play an important role in the induction of hibernation-like dedifferentiation of the cocultured adult rabbit CMs.
authors.affiliation: Department of Molecular Cell Biology, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands.
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Driesen
authors.forename: Fons K
authors.initials: FK
authors.lastname: Verheyen
authors.forename: Gerrit D
authors.initials: GD
authors.lastname: Dispersyn
authors.forename: Fred
authors.initials: F
authors.lastname: Thoné
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Lenders
authors.forename: Frans C S
authors.initials: FC
authors.lastname: Ramaekers
authors.forename: Marcel
authors.initials: M
authors.lastname: Borgers
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000818:Animals; D015820:Cadherins / Q000032:analysis; D002448:Cell Adhesion / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000502:physiology; D002478:Cells, Cultured; D018920:Coculture Techniques; D003561:Cytarabine / Q000494:pharmacology; D051180:Desmoplakins / Q000032:analysis; D005347:Fibroblasts / Q000737:chemistry / Q000187:drug effects / Q000473:pathology*; D006352:Heart Ventricles / Q000737:chemistry / Q000473:pathology* / Q000503:physiopathology; D019012:Integrin beta1 / Q000032:analysis; D007700:Kinetics; D017682:Myocardial Stunning / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D032383:Myocytes, Cardiac / Q000737:chemistry / Q000473:pathology*; D011817:Rabbits; D016596:Vinculin / Q000032:analysis
chemical_list: D015820:Cadherins; D051180:Desmoplakins; D019012:Integrin beta1; D003561:Cytarabine; D016596:Vinculin