title: Arrhythmogenic right ventricular cardiomyopathy mutations alter shear response without changes in cell-cell adhesion.
abstract: OBJECTIVE
  The majority of patients diagnosed with arrhythmogenic right ventricular cardiomyopathy (ARVC) have mutations in genes encoding desmosomal proteins, raising the possibility that abnormal intercellular adhesion plays an important role in disease pathogenesis. We characterize cell mechanical properties and molecular responses to oscillatory shear stress in cardiac myocytes expressing mutant forms of the desmosomal proteins, plakoglobin and plakophilin, which are linked to ARVC in patients.
  
  
  RESULTS
  Cells expressing mutant plakoglobin or plakophilin showed no differences in cell-cell adhesion relative to controls, while knocking down these proteins weakened cell-cell adhesion. However, cells expressing mutant plakoglobin failed to increase the amount of immunoreactive signal for plakoglobin or N-cadherin at cell-cell junctions in response to shear stress, as seen in control cells. Cells expressing mutant plakophilin exhibited a similar attenuation in the shear-induced increase in junctional plakoglobin immunoreactive signal in response to shear stress, suggesting that the phenotype is independent of the type of mutant protein being expressed. Cells expressing mutant plakoglobin also showed greater myocyte apoptosis compared with controls. Apoptosis rates increased greatly in response to shear stress in cells expressing mutant plakoglobin, but not in controls. Abnormal responses to shear stress in cells expressing either mutant plakoglobin or plakophilin could be reversed by SB216763, a GSK3β inhibitor.
  
  
  CONCLUSIONS
  Desmosomal mutations linked to ARVC do not significantly affect cell mechanical properties, but cause myocytes to respond abnormally to mechanical stress through a mechanism involving GSK3β. These results may help explain why patients with ARVC experience disease exacerbations following strenuous exercise.
authors.affiliation: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 500 W 120th Street, MC 8904, New York, NY 10027, USA.
authors.forename: Venkatesh
authors.initials: V
authors.lastname: Hariharan
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Boston, MA, USA Department of Pathology, Harvard Medical School, Boston, MA, USA.
authors.forename: Angeliki
authors.initials: A
authors.lastname: Asimaki
authors.affiliation: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 500 W 120th Street, MC 8904, New York, NY 10027, USA.
authors.forename: Jarett E
authors.initials: JE
authors.lastname: Michaelson
authors.affiliation: Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA Department of Medicine, Harvard Medical School, Boston, MA, USA.
authors.forename: Eva
authors.initials: E
authors.lastname: Plovie
authors.affiliation: Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA Department of Medicine, Harvard Medical School, Boston, MA, USA.
authors.forename: Calum A
authors.initials: CA
authors.lastname: MacRae
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Boston, MA, USA Department of Pathology, Harvard Medical School, Boston, MA, USA.
authors.forename: Jeffrey E
authors.initials: JE
authors.lastname: Saffitz
authors.affiliation: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 500 W 120th Street, MC 8904, New York, NY 10027, USA hayden.huang@columbia.edu.
authors.forename: Hayden
authors.initials: H
authors.lastname: Huang
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis; D019571:Arrhythmogenic Right Ventricular Dysplasia / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D020022:Genetic Predisposition to Disease; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D007365:Intercellular Junctions / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D040542:Mechanotransduction, Cellular / Q000187:drug effects; D009154:Mutation; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D051191:Plakophilins / Q000235:genetics* / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D017208:Rats, Wistar; D013314:Stress, Mechanical; D013997:Time Factors; D014162:Transfection; D051185:gamma Catenin / Q000235:genetics* / Q000378:metabolism
chemical_list: D015820:Cadherins; C570099:N-cadherin, rat; D009419:Nerve Tissue Proteins; D051191:Plakophilins; D047428:Protein Kinase Inhibitors; D051185:gamma Catenin; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D038362:Glycogen Synthase Kinase 3
keywords: Arrhythmia; Cardiomyopathy; Desmosome; Plakoglobin; Shear stress