Force generation and protease gene expression in organotypic co-cultures of fibroblasts and keratinocytes.

Fibroblast-epithelium interactions are crucial for successful tissue engineering of skin and oral mucosal equivalents. In this study, we assessed early force generation in organotypic fibroblast-epithelium co-cultures, using normal human keratinocytes (NHK) and HPV16-transformed (UP) cells. During the initial 2 h period, organotypic co-cultures containing both epithelial cell types produced significantly more force than fibroblasts alone (p < 0.05). After 2 h, the epithelial contribution became diminished and did not significantly contribute to intrinsic force generation by fibroblasts, and no differences were observed when using UP vs. NHK. We then measured protease gene expression at the end of the experimental period. Distinct differences were evident in protease expression both between NHK-human skin fibroblast (HSF) vs. UP-HSF co-cultures and compared to fibroblasts alone. We conclude that whilst the very early contractile response of fibroblasts is enhanced by the overlying epithelium, this becomes diminished as the fibroblast response becomes predominant and it does contribute to tissue remodelling via regulation of protease expression.