Adhesiveness of human uterine epithelial RL95-2 cells to trophoblast: rho protein regulation.
Embryo implantation involves adhesion of trophoblast cells to the epithelial lining of the endometrium. Using an in-vitro model to simulate this initial interaction, we previously reported that attachment of human trophoblast-like JAR spheroids to human uterine epithelial RL95-2 cells provokes a Ca(2+) influx in RL95-2 cells depending on apically localized integrin receptors. Here, we demonstrate that adhesiveness of RL95-2 cells for JAR spheroids, measured by a centrifugal force-based adhesion assay, is dependent on Rho GTPases, most likely RhoA. Cellular expression and distribution of RhoA were studied by fluorescence confocal microscopy, focusing on the localization of RhoA and F-actin within the adhesion sites between JAR and RL95-2 cells. Contact areas contained high amounts of RhoA and F-actin fibres near the plasma membrane. To determine whether Rho GTPases may influence JAR cell binding, we treated RL95-2 cells with Clostridium difficile toxin A, which specifically inactivates Rho GTPases. Toxin A treatment changed the subcellular distribution of endogenous RhoA in RL95-2 cells and altered RhoA and F-actin colocalization. Adhesion of JAR spheroids to RL95-2 cells treated with toxin A was largely suppressed. These data indicate that Rho GTPases, most likely RhoA, play an important role in uterine epithelial RL95-2 cells for trophoblast binding, and suggest that RhoA may be involved in local signalling cascades during early embryo implantation in vivo.
Heneweer
Carola
C
Institut für Anatomie, Universitätsklinikum Essen, D-45122 Essen, Germany.
Kruse
Lars Hendric
LH
Kindhäuser
Felix
F
Schmidt
Martina
M
Jakobs
Karl H
KH
Denker
Hans-Werner
HW
Thie
Michael
M
D000199:Actins / Q000187:drug effects / Q000378:metabolism; D001427:Bacterial Toxins / Q000494:pharmacology; D002448:Cell Adhesion / Q000502:physiology*; D002478:Cells, Cultured; D004768:Enterotoxins / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005260:Female; D006801:Humans; D008856:Microscopy, Fluorescence / Q000379:methods; D014327:Trophoblasts / Q000166:cytology* / Q000378:metabolism; D014599:Uterus / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000187:drug effects / Q000378:metabolism*
D000199:Actins; D001427:Bacterial Toxins; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile; D020742:rhoA GTP-Binding Protein