Up-regulation of prostaglandin EP4 receptor messenger RNA in fetal rabbit skin wound

Background: Scar formation and subglottic stenosis often cause health probl ems in surgical otolaryngology. However, fetal wounds demonstrate scarless healing. The underlying mechanism remains poorly understood. We isolated di fferentially expressed genes by comparison between nonwounded with wounded skin of fetal and adult rabbits. Methods: Skin incisional wounds were made in fetal (21 to 23 days' gestatio n) and adult rabbits. Nonwounded and wounded skin were harvested 12 hours a fter surgery. Total RNA was extracted. By means of messenger RNA differenti al display, differentially expressed complementary DNA fragments were isola ted, cloned, and sequenced. The expressed transcripts were verified by reve rse RNA dot blot and semiquantitative reverse transcription and polymerase chain reaction. Results: One complementary DNA tag that was induced in fetal skin wounds an d repressed in adult skin wounds was isolated. The sequence of this complem entary DNA (352 base pairs) encodes the messenger RNA for the E-prostanoid (EP) 4 receptor for prostaglandin E-2 (PGE(2)). The truly differential expr ession of the transcript was confirmed. In normal skin, the EP4 receptor me ssenger RNA levels were higher in adults than in fetuses. Twelve hours afte r wounding, the EP4 receptor transcript was remarkably induced in fetal ski n wounds but repressed in adult skin wounds. Conclusions: Our study demonstrates the differential expression of the EP4 receptor messenger RNA in fetal and adult skin before and 12 hours after wo unding. Our results suggest that prostaglandin E-2 is involved in the diffe rential cellular responses and in the regulation of the intracellular signa l transduction through its binding to EP4 receptor during fetal wound repai r.