title: Polarized actin structural dynamics in response to cyclic uniaxial stretch.
abstract: Endothelial cell (EC) alignment to directional flow or stretch supports anti-inflammatory functions, but mechanisms controlling polarized structural adaptation in response to physical cues remain unclear. This study aimed to determine whether factors associated with early actin edge ruffling implicated in cell polarization are prerequisite for stress fiber (SF) reorientation in response to cyclic uniaxial stretch. Time-lapse analysis of EGFP-actin in confluent ECs showed that onset of either cyclic uniaxial or equibiaxial stretch caused a non-directional increase in edge ruffling. Edge activity was concentrated in a direction perpendicular to the stretch axis after 60 min, consistent with the direction of SF alignment. Rho-kinase inhibition caused reorientation of both stretch-induced edge ruffling and SF alignment parallel to the stretch axis. Arp2/3 inhibition attenuated stretch-induced cell elongation and disrupted polarized edge dynamics and microtubule organizing center reorientation, but it had no effect on the extent of SF reorientation. Disrupting localization of p21-activated kinase (PAK) did not prevent stretch-induced SF reorientation, suggesting that this Rac effector is not critical in regulating stretch-induced cytoskeletal remodeling. Overall, these results suggest that directional edge ruffling is not a primary mechanism that guides SF reorientation in response to stretch; the two events are coincident but not causal.
authors.affiliation: Department of Biomedical Engineering, University of Virginia, P. O. Box 800759, Charlottesville, Virginia 22908.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Huang
authors.affiliation: Department of Biomedical Engineering, University of Virginia, P. O. Box 800759, Charlottesville, Virginia 22908 ; Robert M. Berne Cardiovascular Research Center, University of Virginia, P. O. Box 800759, Charlottesville, Virginia 22908.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Helmke
keywords: endothelial cell; mechanotransduction; planar cell polarity; substrate strain
references.citation: J Biol Chem. 2010 Sep 3;285(36):27944-57
references.pmid: 20566646
references.citation: Biophys J. 1990 Feb;57(2):325-33
references.pmid: 2317554
references.citation: EMBO J. 2002 Dec 16;21(24):6791-800
references.pmid: 12486000
references.citation: Circ Res. 2002 Apr 5;90(6):697-702
references.pmid: 11934838
references.citation: J Cell Sci. 2009 Oct 15;122(Pt 20):3644-51
references.pmid: 19812308
references.citation: Ann Biomed Eng. 1999 Nov-Dec;27(6):712-20
references.pmid: 10625144
references.citation: J Cell Biol. 2006 May 8;173(3):383-94
references.pmid: 16651381
references.citation: J Vasc Surg. 1991 May;13(5):744-6
references.pmid: 2027223
references.citation: J Cell Biol. 2002 Jul 8;158(1):153-64
references.pmid: 12105187
references.citation: J Vasc Res. 2002 Nov-Dec;39(6):465-76
references.pmid: 12566972
references.citation: Cell Motil Cytoskeleton. 1998;40(4):317-30
references.pmid: 9712262
references.citation: PLoS One. 2009;4(3):e4853
references.pmid: 19319193
references.citation: J Cell Biol. 2003 Apr 28;161(2):429-39
references.pmid: 12719476
references.citation: Annu Rev Biomed Eng. 1999;1:299-329
references.pmid: 11701491
references.citation: J Cell Biol. 2002 May 27;157(5):819-30
references.pmid: 12021256
references.citation: Cell. 2005 May 6;121(3):451-63
references.pmid: 15882626
references.citation: Am J Physiol Heart Circ Physiol. 2007 Mar;292(3):H1209-24
references.pmid: 17098825
references.citation: Am J Respir Cell Mol Biol. 2002 Apr;26(4):453-64
references.pmid: 11919082
references.citation: Biophys J. 2003 Apr;84(4):2691-9
references.pmid: 12668477
references.citation: J Cell Biol. 1981 Nov;91(2 Pt 1):589-94
references.pmid: 7309800
references.citation: Ann Biomed Eng. 2010 Jan;38(1):208-22
references.pmid: 19856213
references.citation: J Biol Chem. 2004 Nov 5;279(45):46621-30
references.pmid: 15333633
references.citation: Ann Biomed Eng. 2010 May;38(5):1728-40
references.pmid: 20195762
references.citation: Mol Cell Biomech. 2008 Jan 1;5(4):247-258
references.pmid: 20084179
references.citation: PLoS One. 2010 Aug 30;5(8):e12470
references.pmid: 20814573
references.citation: Nat Rev Mol Cell Biol. 2006 Oct;7(10):713-26
references.pmid: 16990851
references.citation: Proc Natl Acad Sci U S A. 2005 Nov 1;102(44):15895-900
references.pmid: 16247009
references.citation: J Cell Biol. 2007 Feb 26;176(5):719-27
references.pmid: 17312022
references.citation: Exp Cell Res. 2001 Aug 1;268(1):104-14
references.pmid: 11461123
references.citation: J Cell Biochem. 2005 Dec 15;96(6):1110-26
references.pmid: 16167340
references.citation: J Cell Biol. 1999 Nov 15;147(4):831-44
references.pmid: 10562284
references.citation: Ann Biomed Eng. 1998 May-Jun;26(3):409-16
references.pmid: 9570224
references.citation: Circ Res. 2000 Apr 14;86(7):745-52
references.pmid: 10764407
references.citation: Biophys J. 2008 Sep 15;95(6):3066-78
references.pmid: 18586851
references.citation: Am J Physiol Cell Physiol. 2007 Nov;293(5):C1616-26
references.pmid: 17855768
references.citation: J Cell Sci. 2003 Feb 15;116(Pt 4):743-56
references.pmid: 12538774
references.citation: J Biomech. 2001 Dec;34(12):1563-72
references.pmid: 11716858
references.citation: Cell Mol Bioeng. 2011 Jun 1;4(2):205-219
references.pmid: 21643526
references.citation: Biochem Biophys Res Commun. 2010 Oct 22;401(3):344-9
references.pmid: 20849825
references.citation: Am J Physiol. 1996 Aug;271(2 Pt 1):C635-49
references.pmid: 8770005
references.citation: Proc Natl Acad Sci U S A. 2002 Mar 19;99(6):3546-51
references.pmid: 11891289
references.citation: Tissue Eng. 2007 Jan;13(1):207-17
references.pmid: 17518594
references.citation: Microvasc Res. 1991 Nov;42(3):245-54
references.pmid: 1779881
references.citation: Nature. 2009 Aug 20;460(7258):1031-4
references.pmid: 19648907