title: Abnormal muscle mechanosignaling triggers cardiomyopathy in mice with Marfan syndrome.
abstract: Patients with Marfan syndrome (MFS), a multisystem disorder caused by mutations in the gene encoding the extracellular matrix (ECM) protein fibrillin 1, are unusually vulnerable to stress-induced cardiac dysfunction. The prevailing view is that MFS-associated cardiac dysfunction is the result of aortic and/or valvular disease. Here, we determined that dilated cardiomyopathy (DCM) in fibrillin 1-deficient mice is a primary manifestation resulting from ECM-induced abnormal mechanosignaling by cardiomyocytes. MFS mice displayed spontaneous emergence of an enlarged and dysfunctional heart, altered physical properties of myocardial tissue, and biochemical evidence of chronic mechanical stress, including increased angiotensin II type I receptor (AT1R) signaling and abated focal adhesion kinase (FAK) activity. Partial fibrillin 1 gene inactivation in cardiomyocytes was sufficient to precipitate DCM in otherwise phenotypically normal mice. Consistent with abnormal mechanosignaling, normal cardiac size and function were restored in MFS mice treated with an AT1R antagonist and in MFS mice lacking AT1R or β-arrestin 2, but not in MFS mice treated with an angiotensin-converting enzyme inhibitor or lacking angiotensinogen. Conversely, DCM associated with abnormal AT1R and FAK signaling was the sole abnormality in mice that were haploinsufficient for both fibrillin 1 and β1 integrin. Collectively, these findings implicate fibrillin 1 in the physiological adaptation of cardiac muscle to elevated workload.
authors: Jason R
authors: JR
authors: Cook
authors: Luca
authors: L
authors: Carta
authors: Ludovic
authors: L
authors: Bénard
authors: Elie R
authors: ER
authors: Chemaly
authors: Emily
authors: E
authors: Chiu
authors: Satish K
authors: SK
authors: Rao
authors: Thomas G
authors: TG
authors: Hampton
authors: Peter
authors: P
authors: Yurchenco
authors: Kevin D
authors: KD
authors: Costa
authors: Roger J
authors: RJ
authors: Hajjar
authors: Francesco
authors: F
authors: Ramirez
mesh_terms: D000328:Adult; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D000818:Animals; D002311:Cardiomyopathy, Dilated / Q000209:etiology / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D002648:Child; D003430:Cross-Sectional Studies; D005109:Extracellular Matrix / Q000378:metabolism; D000071838:Fibrillin-1; D000071837:Fibrillins; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D006801:Humans; D019808:Losartan / Q000494:pharmacology; D020935:MAP Kinase Signaling System; D008297:Male; D008382:Marfan Syndrome / Q000150:complications / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D040542:Mechanotransduction, Cellular; D051379:Mice; D008822:Mice, Transgenic; D008840:Microfilament Proteins / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism; D009929:Organ Size; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism; D054392:Adipokines
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D000071838:Fibrillin-1; D000071837:Fibrillins; D051417:Focal Adhesion Kinase 1; D019808:Losartan; D008840:Microfilament Proteins; D044140:Receptor, Angiotensin, Type 1; C000605722:FBN1 protein, human; D054392:Adipokines; C000605724:Fbn1 protein, mouse; C496051:Ptk2 protein, mouse