title: Cyclic stretch of embryonic cardiomyocytes increases proliferation, growth, and expression while repressing Tgf-β signaling.
abstract: Perturbed biomechanical stimuli are thought to be critical for the pathogenesis of a number of congenital heart defects, including Hypoplastic Left Heart Syndrome (HLHS). While embryonic cardiomyocytes experience biomechanical stretch every heart beat, their molecular responses to biomechanical stimuli during heart development are poorly understood. We hypothesized that biomechanical stimuli activate specific signaling pathways that impact proliferation, gene expression and myocyte contraction. The objective of this study was to expose embryonic mouse cardiomyocytes (EMCM) to cyclic stretch and examine key molecular and phenotypic responses. Analysis of RNA-Sequencing data demonstrated that gene ontology groups associated with myofibril and cardiac development were significantly modulated. Stretch increased EMCM proliferation, size, cardiac gene expression, and myofibril protein levels. Stretch also repressed several components belonging to the Transforming Growth Factor-β (Tgf-β) signaling pathway. EMCMs undergoing cyclic stretch had decreased Tgf-β expression, protein levels, and signaling. Furthermore, treatment of EMCMs with a Tgf-β inhibitor resulted in increased EMCM size. Functionally, Tgf-β signaling repressed EMCM proliferation and contractile function, as assayed via dynamic monolayer force microscopy (DMFM). Taken together, these data support the hypothesis that biomechanical stimuli play a vital role in normal cardiac development and for cardiac pathology, including HLHS.
authors.affiliation: Department of Cardiology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, United States.
authors.forename: Indroneal
authors.initials: I
authors.lastname: Banerjee
authors.affiliation: Department of Pediatrics (Cardiology), University of California San Diego, United States.
authors.forename: Katrina
authors.initials: K
authors.lastname: Carrion
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of California San Diego, United States.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Serrano
authors.affiliation: Department of Pediatrics (Cardiology), University of California San Diego, United States.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Dyo
authors.affiliation: Biomedical Genomics Microarray Core Facility, University of California San Diego, United States.
authors.forename: Roman
authors.initials: R
authors.lastname: Sasik
authors.affiliation: Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, United States.
authors.forename: Sean
authors.initials: S
authors.lastname: Lund
authors.affiliation: Muscle Development and Regeneration Program, Sanford-Burnham Medical Research Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, United States.
authors.forename: Erik
authors.initials: E
authors.lastname: Willems
authors.affiliation: Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, United States; Department of Pediatrics (Allergy), University of California San Diego, United States; Rady Children's Hospital San Diego, United States.
authors.forename: Seema
authors.initials: S
authors.lastname: Aceves
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of California San Diego, United States; Cell and Developmental Biology, University of California San Diego, United States.
authors.forename: Rudolph
authors.initials: R
authors.lastname: Meili
authors.affiliation: Muscle Development and Regeneration Program, Sanford-Burnham Medical Research Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, United States.
authors.forename: Mark
authors.initials: M
authors.lastname: Mercola
authors.affiliation: Department of Cardiology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, United States.
authors.forename: Ju
authors.initials: J
authors.lastname: Chen
authors.affiliation: School of Pharmacology Keck Graduate Institute, 9500 Gilman Drive, La Jolla, CA 92093, United States.
authors.forename: Alexander
authors.initials: A
authors.lastname: Zambon
authors.affiliation: Department of Medicine, Medical University of South Carolina, 135 Cannon Street, Suite 303 MSC 835, Charleston, SC 29425, United States.
authors.forename: Gary
authors.initials: G
authors.lastname: Hardiman
authors.affiliation: Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, United States.
authors.forename: Taylor A
authors.initials: TA
authors.lastname: Doherty
authors.affiliation: Department of Cardiology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, United States.
authors.forename: Stephan
authors.initials: S
authors.lastname: Lange
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of California San Diego, United States; Institute for Engineering in Medicine, University of California San Diego, United States.
authors.forename: Juan C
authors.initials: JC
authors.lastname: del Álamo
authors.affiliation: Department of Pediatrics (Cardiology), University of California San Diego, United States; Rady Children's Hospital San Diego, United States; Institute for Engineering in Medicine, University of California San Diego, United States. Electronic address: vnigam@ucsd.edu.
authors.forename: Vishal
authors.initials: V
authors.lastname: Nigam
mesh_terms: D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D048429:Cell Size; D004622:Embryo, Mammalian / Q000166:cytology*; D005786:Gene Expression Regulation / Q000187:drug effects; D063990:Gene Ontology; D051379:Mice; D009200:Myocardial Contraction / Q000187:drug effects; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D009210:Myofibrils / Q000378:metabolism; D017423:Sequence Analysis, RNA; D015398:Signal Transduction / Q000187:drug effects; D013314:Stress, Mechanical; D016212:Transforming Growth Factor beta / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D016212:Transforming Growth Factor beta
keywords: Cardiac development; Cardiomyocytes; Contractility; Gene regulation; Hypoplastic Left Heart Syndrome; Mechanical stretch