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Umbarkar P, Singh AP, Gupte M, Verma VK, Galindo CL, Guo Y, Zhang Q, McNamara JW, Force T, Lal H. Cardiomyocyte SMAD4-Dependent TGF-β Signaling is Essential to Maintain Adult Heart Homeostasis. ACTA ACUST UNITED AC 2019; 4:41-53. [PMID: 30847418 PMCID: PMC6390466 DOI: 10.1016/j.jacbts.2018.10.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 08/10/2018] [Accepted: 08/10/2018] [Indexed: 12/25/2022]
Abstract
SMAD4 is the central intracellular mediator of TGF-β pathway. CM-specific loss of SMAD4 causes cardiac dysfunction independent of fibrotic remodeling. Deletion CM-SMAD4 affects CM survival. CM-SMAD4 loss leads to down-regulation of several ion channels’ genes, resulting in cardiac conduction abnormalities. CM-SMAD4 deletion alters sarcomere shortening kinetics, in parallel with reduction in cardiac myosin-binding protein C levels. These results demonstrate a fundamental role for CM-SMAD4–dependent TGF-β signaling in adult heart homeostasis.
The role of the transforming growth factor (TGF)-β pathway in myocardial fibrosis is well recognized. However, the precise role of this signaling axis in cardiomyocyte (CM) biology is not defined. In TGF-β signaling, SMAD4 acts as the central intracellular mediator. To investigate the role of TGF-β signaling in CM biology, the authors deleted SMAD4 in adult mouse CMs. We demonstrate that CM-SMAD4–dependent TGF-β signaling is critical for maintaining cardiac function, sarcomere kinetics, ion-channel gene expression, and cardiomyocyte survival. Thus, our findings raise a significant concern regarding the therapeutic approaches that rely on systemic inhibition of the TGF-β pathway for the management of myocardial fibrosis.
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Key Words
- CM, cardiomyocyte
- CSA, cross-sectional area
- CTL, control
- DCM, dilated cardiomyopathy
- KO, knockout
- LV, left ventricle/ventricular
- MAPK, mitogen-activated protein kinase
- MCM, MerCreMer
- PI3K, phosphoinositide-3 kinase
- RNA-Seq, RNA sequencing
- SMAD4
- TAK1, transforming growth factor beta–activated kinase 1
- TAM, tamoxifen
- TGF, transforming growth factor
- TGF-β
- cMyBP-C, cardiac myosin-binding protein C
- cardiomyocyte
- cardiomyopathy
- fibrosis
- heart failure
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Affiliation(s)
- Prachi Umbarkar
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Anand P Singh
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Manisha Gupte
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Vipin K Verma
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Cristi L Galindo
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Yuanjun Guo
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Pharmacology, Vanderbilt University, Nashville, Tennessee
| | - Qinkun Zhang
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - James W McNamara
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Thomas Force
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Hind Lal
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
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