Stromal-epithelial interactions in the cornea.
Stromal-epithelial interactions are key determinants of corneal function. Bi-directional communications occur in a highly coordinated manner between these corneal tissues during normal development, homeostasis, and wound healing. The best characterized stromal to epithelial interactions in the cornea are mediated by the classical paracrine mediators hepatocyte growth factor (HGF) and keratinocyte growth factor (KGF). HGF and KGF are produced by the keratocytes to regulate proliferation, motility, differentiation, and possibly other functions, of epithelial cells. Other cytokines produced by keratocytes may also contribute to these interactions. Epithelial to stromal interactions are mediated by cytokines, such as interleukin-1 (IL-1) and soluble Fas ligand, that are released by corneal epithelial cells in response to injury. Other, yet to be identified, cytokine systems may be released from the unwounded corneal epithelium to regulate keratocyte viability and function. IL-1 appears to be a master regulator of corneal wound healing that modulates functions such as matrix metalloproteinase production, HGF and KGF production, and apoptosis of keratocyte cells following injury. The Fas/Fas ligand system has been shown to contribute to the immune privileged status of the cornea. However, this cytokine-receptor system probably also modulates corneal cell apoptosis following infection by viruses such as herpes simplex and wounding. Pharmacologic control of stromal-epithelial interactions appears to offer the potential to regulate corneal wound healing and, possibly, treat corneal diseases in which these interactions have a central role.
Wilson
S E
SE
Department of Ophthalmology, University of Washington, Seattle 98195-6485, USA. sewilson@u.washington.edu
Liu
J J
JJ
Mohan
R R
RR
D003319:Corneal Stroma / Q000502:physiology*; D019573:Epithelium, Corneal / Q000502:physiology*; D053222:Fas Ligand Protein; D051526:Fibroblast Growth Factor 10; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors; D006133:Growth Substances / Q000502:physiology; D017228:Hepatocyte Growth Factor / Q000502:physiology; D006801:Humans; D007375:Interleukin-1 / Q000502:physiology; D007765:Lacrimal Apparatus / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D013666:Tears / Q000378:metabolism; D019014:fas Receptor / Q000378:metabolism
C505661:FASLG protein, human; C496453:FGF7 protein, human; D053222:Fas Ligand Protein; D051526:Fibroblast Growth Factor 10; D006133:Growth Substances; D007375:Interleukin-1; D008562:Membrane Glycoproteins; D019014:fas Receptor; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors; D017228:Hepatocyte Growth Factor