Integrins β5, β3 and αv are apically distributed in endometrial epithelium

Several adhesion molecules have been shown to occur at the surface of endometrial cells. One of these is the integrin αv subunit which associates with various β chains including β5. We demonstrate the presence of integrin β5 polypeptide in human endometrial epithelial cells throughout the menstrual cycle using immunocytochemistry with monospecific antibodies, and at the mRNA level by thermal amplification from endometrial cDNA. Integrin β5 is also found in a population of bone marrow-derived cells. A notable feature of the distribution of the β5 subunit in the glandular and luminal epithelium is its apical localization, which may suggest an involvement in implantation. However, no evidence was found for regulated expression of epithelial β5. In mouse, the β5 subunit is found at both the apical and basal surface of epithelial cells and expression is essentially oestrous cycle-independent. Comparisons are made in both species with the distribution of the αv and β3 subunits which also localize to the apical epithelium. © European Society for Human Reproduction and Embryology.