Enhancement of fibronectin-induced migration of corneal epithelial cells by cytokines.

PURPOSE

To examine the enhancing effect of cytokines on the corneal epithelial cell migration induced by fibronectin (FN).

METHODS

A modified Boyden chamber method was used to detect chemotactic cell migration. Cells plated in the inner chamber were incubated with FN, cytokines, or both in the outer chamber at 37 degrees C for 24 hours. Cells that had migrated were stained and counted under a microscope. Checkerboard analysis was used to distinguish chemotaxis from chemokinesis.

RESULTS

FN induced epithelial cell migration, but interleukin (IL)-1 alpha, IL-6, tumor necrosis factor (TNF)-alpha, and epidermal growth factor (EGF) alone did not. These cytokines, even at very low concentrations (0.1 to 100 pg/ml), enhanced FN-induced migration to levels about twofold those observed with FN alone. Checkerboard analysis demonstrated that EGF, but not IL-1 alpha, IL-6, or TNF-alpha, stimulated the chemokinesis of corneal epithelial cells in the presence of FN.

CONCLUSION

EGF enhanced corneal epithelial cell migration by increasing chemokinesis, whereas IL-1 alpha, IL-6, and TNF-alpha enhanced this migration by increasing the FN-induced chemotactic activity, although these cytokines themselves do not have chemokinetic and chemotactic activity.