title: Nuclear morphology and deformation in engineered cardiac myocytes and tissues.
abstract: Cardiac tissue engineering requires finely-tuned manipulation of the extracellular matrix (ECM) microenvironment to optimize internal myocardial organization. The myocyte nucleus is mechanically connected to the cell membrane via cytoskeletal elements, making it a target for the cellular response to perturbation of the ECM. However, the role of ECM spatial configuration and myocyte shape on nuclear location and morphology is unknown. In this study, printed ECM proteins were used to configure the geometry of cultured neonatal rat ventricular myocytes. Engineered one- and two-dimensional tissue constructs and single myocyte islands were assayed using live fluorescence imaging to examine nuclear position, morphology and motion as a function of the imposed ECM geometry during diastolic relaxation and systolic contraction. Image analysis showed that anisotropic tissue constructs cultured on microfabricated ECM lines possessed a high degree of nuclear alignment similar to that found in vivo; nuclei in isotropic tissues were polymorphic in shape with an apparently random orientation. Nuclear eccentricity was also increased for the anisotropic tissues, suggesting that intracellular forces deform the nucleus as the cell is spatially confined. During systole, nuclei experienced increasing spatial confinement in magnitude and direction of displacement as tissue anisotropy increased, yielding anisotropic deformation. Thus, the nature of nuclear displacement and deformation during systole appears to rely on a combination of the passive myofibril spatial organization and the active stress fields induced by contraction. Such findings have implications in understanding the genomic consequences and functional response of cardiac myocytes to their ECM surroundings under conditions of disease.
authors.affiliation: Disease Biophysics Group, Harvard Stem Cell Institute, Wyss Institute for Biologically Inspired Engineering, School of Engineering and Applied Sciences, Harvard University, 29 Oxford St (Rm 322A), Cambridge, MA 02138, United States.
authors.forename: Mark-Anthony P
authors.initials: MA
authors.lastname: Bray
authors.forename: William J
authors.initials: WJ
authors.lastname: Adams
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Geisse
authors.forename: Adam W
authors.initials: AW
authors.lastname: Feinberg
authors.forename: Sean P
authors.initials: SP
authors.lastname: Sheehy
authors.forename: Kevin K
authors.initials: KK
authors.lastname: Parker
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002467:Cell Nucleus / Q000502:physiology* / Q000648:ultrastructure*; D048429:Cell Size; D002478:Cells, Cultured; D055119:Elastic Modulus / Q000502:physiology; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D023822:Tissue Engineering / Q000379:methods*
references.citation: Science. 1997 May 30;276(5317):1425-8
references.pmid: 9162012
references.citation: J Biomech. 1995 Dec;28(12):1529-41
references.pmid: 8666592
references.citation: Nat Cell Biol. 2001 May;3(5):466-72
references.pmid: 11331874
references.citation: Am J Physiol. 1995 Jan;268(1 Pt 1):C252-8
references.pmid: 7840154
references.citation: Biochim Biophys Acta. 2007 May;1773(5):675-86
references.pmid: 17050008
references.citation: Heart Fail Rev. 2000 Oct;5(3):271-80
references.pmid: 16228910
references.citation: J Mol Cell Cardiol. 1985 Oct;17(10):1005-11
references.pmid: 2933527
references.citation: J Cell Biol. 1970 Jan;44(1):218-23
references.pmid: 5409459
references.citation: J Mol Cell Cardiol. 1993 Mar;25(3):303-9
references.pmid: 8510171
references.citation: Eur Heart J. 1984 Dec;5 Suppl F:271-80
references.pmid: 6241897
references.citation: Biorheology. 2003;40(1-3):361-8
references.pmid: 12454427
references.citation: J Clin Invest. 2004 Feb;113(3):349-51
references.pmid: 14755330
references.citation: Anal Quant Cytol Histol. 1999 Apr;21(2):174-80
references.pmid: 10560488
references.citation: J Biomech. 2002 Feb;35(2):177-87
references.pmid: 11784536
references.citation: J Cell Sci. 1992 Dec;103 ( Pt 4):1215-22
references.pmid: 1487498
references.citation: J Cell Sci. 2003 Apr 1;116(Pt 7):1157-73
references.pmid: 12615960
references.citation: J Cell Biochem. 1992 Aug;49(4):357-65
references.pmid: 1429864
references.citation: J Clin Invest. 2004 Feb;113(3):370-8
references.pmid: 14755334
references.citation: J Mol Cell Cardiol. 1996 Oct;28(10):2123-7
references.pmid: 8930807
references.citation: Cardioscience. 1994 Sep;5(3):203-8
references.pmid: 7827258
references.citation: J Orthop Res. 2002 Jan;20(1):29-35
references.pmid: 11853087
references.citation: Proc Natl Acad Sci U S A. 1997 Feb 4;94(3):849-54
references.pmid: 9023345
references.citation: Z Zellforsch Mikrosk Anat. 1970;111(1):143-8
references.pmid: 5487810
references.citation: Lab Invest. 1988 Dec;59(6):857-61
references.pmid: 2974102
references.citation: Ann Biomed Eng. 1998 May-Jun;26(3):409-16
references.pmid: 9570224
references.citation: Ann Thorac Surg. 2003 May;75(5):1450-6
references.pmid: 12735561
references.citation: Biochim Biophys Acta. 2002 Feb 15;1570(1):1-8
references.pmid: 11960682
references.citation: Trends Cell Biol. 2002 Feb;12(2):79-84
references.pmid: 11849971
references.citation: J Cell Biol. 1984 Jun;98(6):1973-84
references.pmid: 6202700
references.citation: J Cell Sci. 1990 Apr;95 ( Pt 4):577-86
references.pmid: 1696579
references.citation: Eur J Cardiothorac Surg. 2006 Oct;30(4):604-10
references.pmid: 16935520
references.citation: J Clin Invest. 1975 Jul;56(1):56-64
references.pmid: 124746
references.citation: FASEB J. 2002 Aug;16(10):1195-204
references.pmid: 12153987
references.citation: Am J Physiol Heart Circ Physiol. 2000 Feb;278(2):H412-9
references.pmid: 10666070
references.citation: J Cell Sci. 1996 Feb;109 ( Pt 2):499-508
references.pmid: 8838673
references.citation: Circ Res. 2006 Mar 17;98(5):705-12
references.pmid: 16469955
references.citation: J Clin Invest. 2004 Feb;113(3):357-69
references.pmid: 14755333
references.citation: Connect Tissue Res. 1994;31(1):45-53
references.pmid: 15609621
references.citation: J Cell Sci. 2004 Jan 1;117(Pt 1):41-52
references.pmid: 14657272
references.citation: Mol Biol Cell. 1998 Nov;9(11):3179-93
references.pmid: 9802905
references.citation: Cell Motil Cytoskeleton. 2002 Jun;52(2):97-106
references.pmid: 12112152
references.citation: Biochem Biophys Res Commun. 2005 Apr 8;329(2):423-8
references.pmid: 15737604
references.citation: Science. 1994 Apr 29;264(5159):696-8
references.pmid: 8171320
references.citation: Langmuir. 2003 Mar 4;19(5):1611-7
references.pmid: 14674434
references.citation: J Biomech Eng. 2004 Oct;126(5):552-8
references.pmid: 15648807