title: Valve interstitial cell shape modulates cell contractility independent of cell phenotype.
abstract: Valve interstitial cells are dispersed throughout the heart valve and play an important role in maintaining its integrity, function, and phenotype. While prior studies have detailed the role of external mechanical and biological factors in the function of the interstitial cell, the role of cell shape in regulating contractile function, in the context of normal and diseased phenotypes, is not well understood. Thus, the aim of this study was to elucidate the link between cell shape, phenotype, and acute functional contractile output. Valve interstitial cell monolayers with defined cellular shapes were engineered via constraining cells to micropatterned protein lines (10, 20, 40, 60 or 80µm wide). Samples were cultured in either normal or osteogenic medium. Cellular shape and architecture were quantified via fluorescent imaging techniques. Cellular contractility was quantified using a valve thin film assay and phenotype analyzed via western blotting, zymography, and qRT-PCR. In all pattern widths, cells were highly aligned, with maximum cell and nuclear elongation occurring for the 10μm pattern width. Cellular contractility was highest for the most elongated cells, but was also increased in cells on the widest pattern (80μm) that also had increased CX43 expression, suggesting a role for both elongated shape and increased cell-cell contact in regulating contractility. Cells cultured in osteogenic medium had greater expression of smooth muscle markers and correspondingly increased contractile stress responses. Cell phenotype did not significantly correlate with altered cell shape, suggesting that cellular shape plays a significant role in the regulation of valve contractile function independent of phenotype.
authors: Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA.
authors: Ishita
authors: I
authors: Tandon
authors: Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA.
authors: Atefeh
authors: A
authors: Razavi
authors: Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA.
authors: Prashanth
authors: P
authors: Ravishankar
authors: Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA.
authors: Addison
authors: A
authors: Walker
authors: Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA.
authors: Nasya M
authors: NM
authors: Sturdivant
authors: Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA.
authors: Ngoc Thien
authors: NT
authors: Lam
authors: Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA.
authors: Jeffrey C
authors: JC
authors: Wolchok
authors: Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA. Electronic address: kbalacha@uark.edu.
authors: Kartik
authors: K
authors: Balachandran
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D048430:Cell Shape; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D006351:Heart Valves / Q000166:cytology* / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000378:metabolism; D010012:Osteogenesis; D010641:Phenotype; D013552:Swine
chemical_list: D015415:Biomarkers
keywords: Cell architecture; Cell phenotype; Cell shape; Contractile stress; Valve interstitial cells