Laminin receptor 1 is differentially expressed in thoracic and limb wounds in the horse

Healing of wounds located on the distal limbs of horses is often complicated by retarded epithelialization and the development of exuberant granulation tissue (proud flesh). Treatments that definitively resolve this pathological process are still unavailable. Molecular studies of the repair mechanism might contribute to the development of new therapeutic strategies. The study presented herein aimed to clone the full length cDNA and to study the spatio-temporal expression profile of mRNA and protein for LAMR1, previously attributed a role in wound epithelialization, during the repair of body and limb wounds in the horse. Cloning was achieved by screening a cDNA library previously derived from 7-day wound biopsies. Expression was studied in unwounded skin and in samples from 1-, 2-, 3-, 4- and 6-week-old wounds of the body and limb. Temporal gene expression was determined by real time polymerase chain reaction (RT-PCR) while protein expression was mapped immunohistochemically. Full-length cDNA for equine LAMR1 was shown to be highly similar to that of other species. The mRNA expression of LAMR1 was significantly up-regulated only in thoracic wounds, 4 and 6 weeks following wounding (upon epithelialization). Cutaneous wounding induced protein expression at both locations. Our data suggest that up-regulation of LAMR1 protein might favour epithelialization during wound healing. However, its interaction with ligands other than laminin complicates data interpretation. Future studies should quantitatively verify the temporal expression of this protein in order to provide the basis for targeted therapies that might enhance epithelialization