Expression of the α2β1 and α3β1 integrins at the surface of mesothelial cells: A potential attachment site of endometrial cells

Objective: To localize α2β1 and α3β1 integrins in the cell membrane of peritoneal mesothelium in vivo and in vitro. Design: Descriptive study using confocal and two-photon laser-scanning microscopy. Setting: University- based laboratory. Patient(s): Women without endometriosis undergoing surgery for benign conditions. Intervention(s): None. Main Outcome Measure(s): Peritoneal biopsies (n = 9) and mesothelial monolayer cultures (n = 4) were incubated with antibodies to the α2 and α3 subunits and to the intact α2β1 and α3β1 integrins. Specimens were examined with laser-scanning microscopy. Result(s): The α2 and α3 subunits and the intact α2β1 and α3β1 integrins were identified at the base of the mesothelial cells (i.e., toward the basement membrane). There was also expression of the α2 and α3 subunits and the intact α2β1 and α3β1 integrins at the cell surface (i.e., toward the peritoneal cavity). Conclusion(s): The resolution of the confocal and two-photon laser-scanning microscope enabled localization of integrins in mesothelial cells. The presence of α2β1 (collagen-laminin receptor) and α3β1 integrins (collagen-laminin-fibronectin receptor) at the base of mesothelial cells suggests a role for these molecules in adhesion to the basement membrane. The presence of these molecules at the cell surface suggests a potential locus for cell adhesion in such processes as endometriosis and cancer metastasis. (C) 2000 by American Society for Reproductive Medicine.