The role of the osteopontin-integrin {alpha}v{beta}3 interaction at implantation: functional analysis using three different in vitro models

STUDY QUESTION Does the interaction between integrin and its ligand osteopontin (OPN) mediate embryonic attachment to endometrial epithelium at implantation? SUMMARY ANSWER OPN of epithelial origin binds the receptor integrin αvβ3 at the maternal surface to support adhesion during the early stages of implantation. WHAT IS KNOWN ALREADY Integrin αvβ3 and OPN are both present in the endometrial luminal epithelium in the mid-secretory phase. STUDY DESIGN, SIZE, DURATION Microscopy of attachment sites of blastocysts (mouse, n = 151, human, n = 8) and OPN- or BSA-coated beads (n = 488) interacting with Ishikawa cell monolayers at 24 and 48 h. Levels of epithelial OPN or integrin αvβ3 were altered by siRNA-mediated targeting and the results compared with non-targeting siRNA or mock-transfected controls. PARTICIPANTS/MATERIALS, SETTING, METHODS In vitro modelling of early implantation with human endometrial cells (Ishikawa) and mouse or human embryos or ligand-coated beads. Immunolocalization of antigen around attached embryos was measured by image analysis with multiple repeats (n > 3), allowing a gradient of relative intensity to be detected. Attachment was quantified using a stability scale and protein expression documented by indirect immunofluorescence. Protein associations were probed by pulldown assays. MAIN RESULTS AND THE ROLE OF CHANCE Integrin and OPN levels were increased in epithelial cells near to attached embryos. The pulldown ...
Source: Human Reproduction - Category: Reproduction Medicine Authors: Tags: Reproductive biology Source Type: research