Activation of the canonical wingless/T-cell factor signaling pathway promotes invasive differentiation of human trophoblast.
The molecular mechanisms governing invasive differentiation of human trophoblasts remain largely elusive. Here, we investigated the role of Wnt-beta-catenin-T-cell factor (TCF) signaling in this process. Reverse transcriptase-polymerase chain reaction and Western blot analyses demonstrated expression of Wnt ligands, frizzled receptors, LRP-6, and TCF-3/4 transcription factors in total placenta and different trophoblast cell models. Immunohistochemistry of placental tissues and differentiating villous explant cultures showed that expression of TCF-3/4 strongly increased in invading trophoblasts. Some of these cells also accumulated dephosphorylated beta-catenin in the nucleus. Wnt3A treatment of primary cytotrophoblasts and SGHPL-5 cells induced activity of TCF-luciferase reporters. Accordingly, the ligand provoked interaction of TCF-3/4 with beta-catenin as assessed in electrophoretic mobility shift assays (EMSAs) and up-regulation of Wnt/TCF target genes as observed by Western blot analyses. Wnt3A stimulated trophoblast migration and invasion through Matrigel, which could be blocked by addition of Dickkopf-1, mediating in-hibition of canonical Wnt signaling. Dickkopf-1 also reduced basal migration, invasion, and proliferation of cytotrophoblasts, suggesting expression of endogenous Wnt ligand(s). Immunohistochemistry revealed that the percentage of extravillous trophoblasts containing nuclear beta-catenin was significantly higher in placentas of complete hydatidiform mole pregnancies as compared to normal placentas. Thus, canonical Wnt signaling may promote invasive trophoblast differentiation, and exaggerated activation of the path-way could contribute to trophoblastic hyperplasia and local invasion.
Department of Obstetrics and Gynecology, Medical University of Vienna, AKH, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
Jürgen
J
Pollheimer
Thomas
T
Loregger
Stefan
S
Sonderegger
Leila
L
Saleh
Sandra
S
Bauer
Martin
M
Bilban
Klaus
K
Czerwenka
Peter
P
Husslein
Martin
M
Knöfler
D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D002824:Chorionic Villi / Q000378:metabolism; D005260:Female; D051157:Frizzled Receptors / Q000378:metabolism; D006801:Humans; D006828:Hydatidiform Mole / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D026502:LDL-Receptor Related Proteins / Q000378:metabolism; D060488:Low Density Lipoprotein Receptor-Related Protein-6; D009924:Organ Culture Techniques; D010766:Phosphorylation; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D015398:Signal Transduction / Q000502:physiology*; D051820:TCF Transcription Factors / Q000378:metabolism*; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D051153:Wnt Proteins / Q000378:metabolism*; D060508:Wnt3 Protein; D060509:Wnt3A Protein; D051176:beta Catenin / Q000378:metabolism
C501126:DKK1 protein, human; D051157:Frizzled Receptors; D036341:Intercellular Signaling Peptides and Proteins; D026502:LDL-Receptor Related Proteins; C555475:LRP6 protein, human; D060488:Low Density Lipoprotein Receptor-Related Protein-6; D051820:TCF Transcription Factors; C555510:WNT3A protein, human; D051153:Wnt Proteins; D060508:Wnt3 Protein; D060509:Wnt3A Protein; D051176:beta Catenin