Cyclic regulation of LPA3 in human endometrium

Lysophosphatidic acid (LPA) belongs to the group of lipid messengers, which plays a pivotal role in the establishment of implantation via its cellular receptor, LPA3. The aims of the present study were to characterize LPA3 mRNA and protein in human endometrium during the normal human menstrual cycle. Forty-three normally cycling volunteers without reproductive disorders were randomized to undergo endometrial sampling on a specific cycle day. Samples were assessed for relative LPA3 mRNA expression using real-time PCR and for LPA3 protein using immunohistochemistry and western blot. The expression of LPA3 mRNA significantly increased during the early and late secretory phase compared with other menstrual phases. LPA3 protein was localized to the epithelial and stromal cells and expression levels followed the same pattern as for LPA3 mRNA. In the normal human menstrual cycle, LPA3 mRNA and protein expression also change, indicating that this gene may be related to the function of the endometrium.