title: Myocyte-restricted focal adhesion kinase deletion attenuates pressure overload-induced hypertrophy.
abstract: Focal adhesion kinase (FAK) is a ubiquitously expressed cytoplasmic tyrosine kinase strongly activated by integrins and neurohumoral factors. Previous studies have shown that cardiac FAK activity is enhanced by hypertrophic stimuli before the onset of overt hypertrophy. Herein, we report that conditional deletion of FAK from the myocardium of adult mice did not affect basal cardiac performance, myocyte viability, or myofibrillar architecture. However, deletion of FAK abolished the increase in left ventricular posterior wall thickness, myocyte cross-sectional area, and hypertrophy-associated atrial natriuretic factor induction following pressure overload. Myocyte-restricted deletion of FAK attenuated the initial wave of extracellular signal-regulated kinase activation and cFos expression induced by adrenergic agonists and biomechanical stress. In addition, we found that persistent challenge of mice with myocyte-restricted FAK inactivation leads to enhanced cardiac fibrosis and cardiac dysfunction in comparison to challenged genetic controls. These studies show that loss of FAK impairs normal compensatory hypertrophic remodeling without a concomitant increase in apoptosis in response to cardiac pressure overload and highlight the possibility that FAK activation may be a common requirement for the initiation of this compensatory response.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA.
authors.forename: Laura A
authors.initials: LA
authors.lastname: DiMichele
authors.forename: Jason T
authors.initials: JT
authors.lastname: Doherty
authors.forename: Mauricio
authors.initials: M
authors.lastname: Rojas
authors.forename: Hilary E
authors.initials: HE
authors.lastname: Beggs
authors.forename: Louis F
authors.initials: LF
authors.lastname: Reichardt
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Mack
authors.forename: Joan M
authors.initials: JM
authors.lastname: Taylor
mesh_terms: D000818:Animals; D017209:Apoptosis; D006332:Cardiomegaly / Q000209:etiology / Q000517:prevention & control*; D004719:Endomyocardial Fibrosis / Q000209:etiology; D051417:Focal Adhesion Kinase 1 / Q000172:deficiency / Q000502:physiology*; D020935:MAP Kinase Signaling System; D051379:Mice; D018345:Mice, Knockout; D032383:Myocytes, Cardiac / Q000166:cytology*; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics; D013314:Stress, Mechanical; D018487:Ventricular Dysfunction, Left / Q000628:therapy
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D051417:Focal Adhesion Kinase 1; C496051:Ptk2 protein, mouse