Do different cells that reside in the same extracellular matrix have discussions about remodeling their environment? Swartz et al. suggest that epithelial cells and fibroblasts might to do just that by sending each other soluble signals. As a way to understand the remodeling that occurs in the bronchial airways of asthma patients, the group designed an artificial system that allows epithelial cells to experience the mechanical stress of airways. Epithelial cells exposed to transmembrane stress secreted fibronectin. At the same time, fibroblasts that were cocultured with the epithelial cells, but not exposed to stress, and also separated from epithelial cells by a porous membrane and culture medium, responded by producing collagen and matrix metalloproteinase-9. These fibrotic responses mimic those observed in asthma patients. The fibroblasts did not respond to conditioned medium from epithelial cells exposed to stress, suggesting that both cell types actively send soluble signals to each other in response to mechanical stress experienced by only one cell type.
M. A. Swartz, D. J. Tschumperlin, R. D. Kamm, J. M. Drazen, Mechanical stress is communicated between different cell types to elicit matrix remodeling. Proc. Natl. Acad. Sci. U.S.A. 98, 6180-6185 (2001). [Abstract] [Full Text]