Phenotypic responses to mechanical stress in fibroblasts from tendon, cornea and skin

Primary fibroblasts isolated from foetal mouse cornea, skin and tendon were subjected to linear shear stress and analysed for morphological parameters and by microarray, as compared with unstimulated controls. Approx. 350 genes were either up- or down-regulated by a significant amount, with 51 of these being common to all three cell types. Approx. 50 % of altered genes in tendon and cornea fibroblasts were changed in common with one of the other cell types, with the remaining approx. 50 % being specific to tendon or cornea. In skin fibroblasts, however, less than 25 % of genes whose transcription was altered were specific only to skin. The functional spectrum of genes that were up- or down-regulated was diverse, with apparent housekeeping genes forming the major category of up-regulated genes. However, a significant number of genes associated with cell adhesion, extracellular matrix and matrix remodelling, as well as cytokines and other signalling factors, were also affected. Somewhat surprisingly, in these latter categories the trend was towards a reduction in mRNA levels. Verification of the mRNA quantity of a subset of these genes was performed by reverse transcriptase PCR and was found to be in agreement with the microarray analysis. These findings provide the first in-depth analysis of phenotypic differences between fibroblast cells from different tissue sources and reveal the responses of these cells to mechanical stress.