Phospholipid growth factors and corneal wound healing

In many tissue types, wound healing involves cell division and migration over and into the wound area to cover and remodel the wound. LPA and other members of the phospholipid lipid growth factor (PLGF) family stimulate many of the activities involved in wound healing. In the rabbit cornea, we have found that keratocytes from wounded corneas have a volume-activated Cl- current activated by LPA and alkenyl-LPA. This current is minimally activated by cyclic PA and SPC, and is not activated by LPA in cells from uninjured corneas. Biochemical examination of PLGFs in aqueous humor and lacrimal fluid before and after wounding identified LPA, alkenyl-GP, PA, and lyso PS, with elevated PLGF activity after wounding. In recent experiments examining human corneal cell lines and cultured cells using RT-PCR, we found mRNA for EDG receptors 1-5, with an apparent increase in EDG-3, -4, and -5 following brief SDS application to cell lines, and EDG receptors 2-5 induction in late-passage human corneal epithelial cells. This work points to a significant role for PLGFs in the corneal wound-healing process.