TY  - JOUR
AU  - Faust, U.
AU  - Hampe, N.
AU  - Rubner, W.
AU  - Kirchgeßner, N.
AU  - Safran, S.
AU  - Hoffmann, B.
AU  - Merkel, R.
TI  - Cyclic Stress at mHz Frequencies Aligns Fibroblasts in Direction of Zero Strain
JO  - PLoS one
VL  - 6
SN  - 1932-6203
CY  - Lawrence, Kan.
PB  - PLoS
M1  - PreJuSER-18984
SP  - 28963
PY  - 2011
N1  - The work by Samuel Safran was funded by a grant from the Isreal Science Foundation (grant number 54/08). The URL of the foundation is http://www.isf.org.il/english/. No further third party funding was received. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
AB  - Recognition of external mechanical signals is vital for mammalian cells. Cyclic stretch, e.g. around blood vessels, is one such signal that induces cell reorientation from parallel to almost perpendicular to the direction of stretch. Here, we present quantitative analyses of both, cell and cytoskeletal reorientation of umbilical cord fibroblasts. Cyclic strain of preset amplitudes was applied at mHz frequencies. Elastomeric chambers were specifically designed and characterized to distinguish between zero strain and minimal stress directions and to allow accurate theoretical modeling. Reorientation was only induced when the applied stretch exceeded a specific amplitude, suggesting a non-linear response. However, on very soft substrates no mechanoresponse occurs even for high strain. For all stretch amplitudes, the angular distributions of reoriented cells are in very good agreement with a theory modeling stretched cells as active force dipoles. Cyclic stretch increases the number of stress fibers and the coupling to adhesions. We show that changes in cell shape follow cytoskeletal reorientation with a significant temporal delay. Our data identify the importance of environmental stiffness for cell reorientation, here in direction of zero strain. These in vitro experiments on cultured cells argue for the necessity of rather stiff environmental conditions to induce cellular reorientation in mammalian tissues.
KW  - Actin Cytoskeleton: metabolism
KW  - Actins: metabolism
KW  - Cell Shape
KW  - Elasticity
KW  - Elastomers
KW  - Fibroblasts: cytology
KW  - Fibroblasts: metabolism
KW  - Humans
KW  - Mechanotransduction, Cellular
KW  - Phosphorylation
KW  - Phosphotyrosine: metabolism
KW  - Stress Fibers: metabolism
KW  - Stress, Mechanical
KW  - Tensile Strength
KW  - Thermodynamics
KW  - Time Factors
KW  - Vinculin: metabolism
KW  - Actins (NLM Chemicals)
KW  - Elastomers (NLM Chemicals)
KW  - Vinculin (NLM Chemicals)
KW  - Phosphotyrosine (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:22194961
C2  - pmc:PMC3241701
UR  - <Go to ISI:>//WOS:000298664400028
DO  - DOI:10.1371/journal.pone.0028963
UR  - https://juser.fz-juelich.de/record/18984
ER  -