SERUM-FREE CULTURE OF MOUSE TRACHEAL EPITHELIAL-CELLS

Numerous investigators have described maintenance of airway epithelial cells from various species in a differentiated state in primary cultu re. Because the number of cells that can be isolated from the mouse tr achea is very small, published techniques are unsuitable for this spec ies. To examine the production of growth factors by murine airway epit helial cells, the authors developed a method for culture of mouse trac heal epithelial cells from explants, in which the population of cells was expanded in the presence of epidermal growth factor and insulin-li ke growth factor-1, which exhibited synergistic mitogenic activity. Af ter subculture, an essentially pure population of epithelial cells was recovered, with a yield approximately tenfold greater than reported u sing protease dissociation of cells from the trachea. Culture of the c ells at passage 2 on a collagen gel substratum induced differentiation toward a synthetic/secretory phenotype, accompanied by marked diminut ion in spontaneous and mitogen-induced DNA synthesis without loss of v iability. In parallel, secretion of immunoreactive transforming growth factor-beta by the epithelial cells was strikingly increased, but cou ld be partially down-regulated in the presence of mitogenic growth fac tors.