Difucosylated oligosaccharide Lewis y is contained within integrin αvβ3 on RL95-2 cells and required for endometrial receptivity

Objective: To investigate whether Lewis Y (LeY) carried by integrin αvβ3 influences integrin αvβ3-mediated adhesion in an in vitro implantation model. Design: Laboratory research. Setting: Reproduction and glycobiology research laboratory. Intervention(s): Specific antibody blockage of LeY or integrin αvβ3 and knockdown of FUT4 expression in RL95-2 cells by transient transfection of FUT4 siRNA. Main Outcome Measure(s): The expression of integrin αvβ3 and LeY in both endometrial tissues and RL95-2 cells was measured. LeY carried by integrin αvβ3 was identified by examining the immunoprecipitated integrin αvβ3. The effect of knocking down FUT4 on the expression of integrin αvβ3 and LeY and their impact on the adhesion of JAR cells to the RL95-2 cells were assessed. Result(s): Integrin αvβ3 and LeY are expressed in both secretory-stage human endometrial tissue and in RL95-2 cells. Although integrin αvβ3 carries LeY, knocking down FUT4 expression only reduces the expression of LeY but not of integrin αvβ3. Knocking down FUT4, antibody blockade of LeY or integrin αvβ3 consistently decreases the adhesion of JAR cells to the RL95-2 cells and prevents focal adhesion kinase (FAK) phosphorylation. Conclusion(s): LeY carried by integrin αvβ3 plays a critical role on the attachment of JAR cells to the RL95-2 cells and activates integrin αvβ3/FAK signaling.