Human trophoblast cell adhesion to extracellular matrix protein, entactin.
OBJECTIVE
Trophoblast interaction with endometrial extracellular matrix (ECM) is crucial during human embryo implantation and placentation. Entactin, a ubiquitous basement membrane glycoprotein, plays a central role in ECM assembly, cell attachment, and chemotaxis. The present study was conducted to examine the possible role of entactin in promoting human trophoblast adhesion.


METHODS
Using an extended life span first trimester trophoblast cell line HTR-8/SVneo (HTR) and a cell adhesion assay, we measured the adherence of human first trimester trophoblasts to recombinant entactin and its domains. Also, we used flow cytometry and indirect immunofluorescence to detect the presence of integrins that may be involved in human trophoblast-entactin interaction; these methods were used to analyze HTR cells, as well as tissue sections and freshly isolated human trophoblasts from first trimester and term placenta.


RESULTS
We found that first trimester trophoblast cells were highly adherent to entactin and its E and G2 domains but not to G1 or G3 domains. Using indirect immunofluorescence and flow cytometry, we found that both beta 1 and beta 3 integrin subunits were expressed on the surface of HTR trophoblast cells adhering to entactin; in contrast, beta 2 and beta 4 integrin subunits were not detected. In addition, we found that alpha v beta 3 was expressed on freshly isolated villous cytotrophoblasts and cytotrophoblast and syncytiotrophoblasts in tissue sections from term placenta. The beta 3 integrin subunit was expressed in cytotrophoblasts and syncytiotrophoblasts in villi of first trimester placental tissue sections.


CONCLUSIONS
Recombinant entactin promotes human trophoblast cell adhesion through both its E and G2 domains and these specific adhesive interactions may be mediated by beta 1 and/or beta 3 class integrins.
Yang
Y
Y
Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
Todt
J C
JC
Svinarich
D M
DM
Qureshi
F
F
Jacques
S M
SM
Graham
C H
CH
Chung
A E
AE
Gonik
B
B
Yelian
F D
FD
D015703:Antigens, CD / Q000096:biosynthesis; D001485:Basement Membrane / Q000378:metabolism; D002448:Cell Adhesion; D002460:Cell Line; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005434:Flow Cytometry; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D039661:Integrin beta3; D016023:Integrins / Q000096:biosynthesis; D008562:Membrane Glycoproteins / Q000378:metabolism*; D010920:Placenta / Q000166:cytology; D010980:Platelet Membrane Glycoproteins / Q000096:biosynthesis; D011485:Protein Binding / Q000276:immunology; D011487:Protein Conformation; D019030:Receptors, Vitronectin / Q000096:biosynthesis; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism*
D015703:Antigens, CD; D016326:Extracellular Matrix Proteins; D039661:Integrin beta3; D016023:Integrins; D008562:Membrane Glycoproteins; D010980:Platelet Membrane Glycoproteins; D019030:Receptors, Vitronectin; C029967:nidogen