Expression of integrins by human trophoblast and differential adhesion to laminin or fibronectin

• Published in: Human reproduction (Oxford) 1993-03, Vol.8 (3), p.475-484
• Main Authors: Burrows, Tanya D., King, Ashley, Loke, Y.W.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Cell Adhesion; Cells, Cultured; fibronectin; Fibronectins - analysis; Fibronectins - metabolism; Flow Cytometry; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Gene Expression; Hormone metabolism and regulation; Humans; Immunohistochemistry; implantation; integrin; Integrins - analysis; Integrins - metabolism; laminin; Laminin - analysis; Laminin - metabolism; Pregnancy. Parturition. Lactation; trophoblast; Trophoblasts - chemistry; Trophoblasts - cytology; Trophoblasts - physiology; Vertebrates: reproduction
• ISSN: 0268-1161; 1460-2350
• DOI: 10.1093/oxfordjournals.humrep.a138075

The process of placental implantation involves a series of transformations of trophoblast from a single polarized epithelial layer resting on a basement membrane (villous trophoblast), to cellular aggregates (trophoblast columns) which ultimately disperse to invade uterine decidua as individual cells (interstitial trophoblast). Such tissue re-modelling is associated with changes in the constituents of the extracellular matrix and in the expression of matrix receptors by the cells, the most relevant being the family of integrins which bind to laminin and fibronectin. In this study we show, by immunohistology and flow cytometry, a gradual loss of laminin receptors with the concomitant acquisition of fibronectin receptors as trophoblast is transformed from the villous phenotype, through the cell columns, into the extravillous population. The pattern of staining for the α5, α6, β1 and β4 subunits indicates that the integrins expressed by trophoblast are predominantly the α5β1 and the α6β4 heterodimers. We have also shown that isolated trophoblast cells assume a flattened, sessile phenotype when cultured on laminin but exhibit a more spreading, motile morphology when plated on fibronectin. In addition, numerous multinucleated giant cells are observed on a fibronectin substrate. Our data suggest that the relative expression of laminin and fibronectin receptors may determine the morphology and behaviour of trophoblast during the process of implantation.