ABSTRACT
OBJECTIVE@#To assess the role of p38 in fibroblast orientation and to explore the cell signal transduction mechanism of cyclic strain induced cell orientation.@*METHODS@#Fibroblasts were seeded onto collagen coated flexible membranes. Membranes were then deformed at 10 cycles per minute under 135 mmHg subatmospheric pressure. Orientation angles of cells treated with or without SB203580 were measured with inverted microscope. P38 phosporylation was analyzed with Western blot.@*RESULTS@#Eighty percent cyclic strain induced cells rotated from 60 degree to 90 degree perpendicular to stretch direction after 4 h strain exposure. P38 phosphorylation reached the peak at 5 min. Fibroblast orientation was inhibited after SB203580 treatment.@*CONCLUSION@#Fibroblast orientation in response to cyclic strain is mediated by p38 phosporylation.
Subject(s)
Humans , Male , Cell Movement , Cells, Cultured , Enzyme Inhibitors , Pharmacology , Fibroblasts , Cell Biology , Imidazoles , Pharmacology , Mechanotransduction, Cellular , Physiology , Phosphorylation , Pyridines , Pharmacology , Skin , Cell Biology , Stress, Mechanical , p38 Mitogen-Activated Protein Kinases , MetabolismABSTRACT
Objective To assess the effects of cyclic stretch on fibroblast orientation in order to find the appropriate cyclic stretch to cause maximum fibroblast orientation and to explore the mechanism of cell signalling since cells are known to orient in response to the application of mechanical forces. Methods Human forehead dermal fibroblasts were seeded onto collagen coated flexible membranes. Membranes were then deformed at 10 cycles per minute by the application of 135 mmHg subatmospheric pressure. This corresponded to strain levels of 0% to 24% from the center to extremity of the flexible membrane. Cells orientation angles were studied by inverted microscopy. Integrin ?1 distribution were studied with immunocytochemical staining and confocal microscopy. Integrin ?1 expression and focal adhesion kinase ( FAK) phosphorylation were analyzed with Western blot analysis. Results A minimum of 15% cell stretch was required to significantly stimulate the fibroblast orientation response. Cyclic stretch induced integrin ?1 redistribution and FAK phosphorylation. Incubation of cells with anti-integrin ?1 prior to the application of stretch abrogated fibroblast orientation and FAK phosphorylation. Conclusion Fibroblast orientation in response to cyclic stretch is mediated at least in part by integrin ?1 through phosphorylation of FAK.