ROLE OF BETA(1) INTEGRINS IN HUMAN ENDOMETRIUM AND DECIDUA DURING IMPLANTATION

The present study was undertaken to investigate the expression and fun ction of beta(1) integrins in human endometrium and decidua. Fluoresce nce-activated flow cytometry demonstrated the greater expression of th e beta(1), alpha(1), alpha(2), and alpha(5) subunits of the beta(1) in tegrin family in cultured stromal cells from the midsecretory phase th an in those of the early proliferative phase. The addition of estradio l (E-2) and progesterone (P) to cultured stromal cells in the early pr oliferative phase increased the expression of beta(1) integrins in vit ro. The immunohistochemical distribution of beta(1) integrins demonstr ated predominantly glandular epithelial staining in the proliferative phase, and stromal and glandular staining in the midsecretory phase. F low cytometry also demonstrated the expression of beta(1), alpha(1), a lpha(2), alpha(3), alpha(5), and alpha(6) subunits of beta(1) integrin family in cultured decidual cells. Immunohistochemistry confirmed the beta(1) integrin cell surface phenotypes in cultured decidual cells o bserved by flow cytometry. In the subsequent experiment, the effects o f antibodies against specific beta(1) integrin heterodimers on mouse e mbryo attachment and spreading were tested to identify the role of bet a(1) integrins in early implantation. We developed assays for the atta chment of mouse embryos and for trophoblastic spreading on cultured hu man decidual cells. The addition of antibodies directed against beta(1 ) and alpha integrin subunits to cultured decidual cells did not affec t the rates of hatching or attachment of the blastocysts, whereas the outgrowth of embryos on the decidual cells was inhibited by their anti bodies in a dose-dependent manner. Thus, beta(1) integrin in human end ometrium and decidua may be important in mediating the organization of extracellular matrix proteins derived from embryos during the early s tage of implantation.