Opposite Effects of Transforming Growth Factor-β Activation and Rho-Associated Kinase Inhibition on Human Trophoblast Migration in a Reconstituted Placental-Endometrial Coculture System

International audiencePlacental implantation involves highly regulated trophoblast invasion of the endometrial stroma. TGF is a known regulator of this process. This study examines the effect of TGF on extravillous cytotrophoblastic cell (EVCT) migration in cocultures of first-trimester human chorionic villus explants and primary human endometrial fibroblasts. Migration of EVCTs was followed by phase-contrast time-lapse micros-copy and was shown to highly depend on the endometrial fibroblast matrix. Interstitial EVCT invasion was also analyzed by confocal microscopy of fluorescently prelabeled trophoblasts and endometrial fibroblasts. As expected, addition of TGF led to inhibition of EVCT invasion of the endometrial cell layer. This inhibition was characterized by formation of compact EVCT stacks at migration fronts and displacement of endometrial fibroblasts. We tested the role of the RhoA/Rho-associated kinase (ROCK) pathway, a TGF-dependent pathway known to regulate cell migration. Interestingly, blocking ROCK with the chemical in-hibitor Y27632 had an effect opposite to TGF activation because it promoted superficial EVCT migration on the en-dometrial cell layer. These data suggest a role for ROCK in the TGF-dependent control of trophoblast migration. Furthermore , they indicate that even though ROCK signaling plays a role in human trophoblast cell invasion, EVCT migration can still occur in the absence of ROCK activity. (Endocrinology 149: 4475– 4485, 2008

Cell type-dependent control of NF-Y activity by TGF-β

International audienceTransforming growth factor b (TGF-b) is a pluripotent cytokine that regulates cell growth and differentiation in a cell type-dependent fashion. TGF-b exerts its effects through the activation of several signaling pathways. One involves membrane proximal events that lead to nuclear translocation of members of the Smad family of transcriptional regulators. TGF-b can also activate MAPK cascades. Here, we show that TGF-b induces nuclear translocation of the NF-YA subunit of the transcription factor NF-Y by a process that requires activation of the ERK cascade. This results in increased binding of endogenous NF-Y to chromatin and TGF-b-dependent transcriptional regulation of the NF-Y target gene cyclin A2. Interestingly, the kinetics of NF-YA relocalization differs between epithelial cells and fibro-blasts. NIH3T3 fibroblasts show an elevated basal level of phosphorylated p38 and delayed nuclear accumulation of NF-YA after TGF-b treatment. In contrast, MDCK cells show low basal p38 activation, higher basal ERK phosphorylation and more rapid localization of NF-YA after induction. Thus, NF-Y activation by TGF-b1 involves ERK1/2 and potentially an interplay between MAPK pathways, thereby opening the possibility for finely tuned transcriptional regulation