MON-025 Activin a Increases Human Trophoblast Invasion by Up-Regulating Integrinb1 Through ALK4
Bibliographic record
Abstract
Abstract Activin A Increases Human Trophoblast Invasion by Up-regulating Integrin β1 Through ALK4 Following implantation, extravillous trophoblast cells (EVTs) derived from trophectoderm invade into the maternal decidua to a certain extent, which is tightly regulated by a variety of factors. Activin A, a member of the TGF-β superfamily, has been shown to stimulate the invasion of human trophoblasts (1). Integrin β1 has been implicated in cancer cell invasion and is consistently expressed in human preimplantation embryos (2). However, whether integrin β1 is integrated in activin A signaling and mediates activin A increased-human trophoblast invasion remain unknown. The objective of our study was to investigate the possible mediation role of integrin β1 in the pro-invasive effect of activin A on trophoblasts and illustrate the underlying molecular mechanisms. Primary and immortalized (HTR8/SVneo) cultures of human trophoblast cells were employed as study models. Real-time qPCR, Western blot, and small interfering RNA (siRNA)-mediated knockdown approaches were used to investigate the molecular determinants of activin A-mediated functions. The integrin β1 protein levels in poorly invasive BeWo,JAR and JEG-3 human choriocarcinoma cells were lower than that in highly invasive HTR8/SVneo cells and primary human EVTs, suggesting the possible essential role of integrin β1 in mediating human trophoblast invasion. The expression levels of integrin β1 were up-regulated in a time-dependent manner after activin A treatment in HTR8/SVneo cells. Importantly, siRNA-mediated down-regulation of integrin β1 significantly attenuated both basal and activin A-induced cell invasion in HTR8/SVneo cells as measured by transwell invasion assay. Interestingly, the TGF-β type I receptors (ALK4/5/7) inhibitor SB431542 abolished activin A-induced activation of SMAD2/SMAD3 as well as activin A-up-regulated integrin 1 expression. Moreover, siRNA-mediated down-regulation of ALK4 or SMAD4 attenuated activin A-up-regulated integrin β1 in both HTR8/SVneo cells and human primary EVT cells. These results reveal that activin A promotes human trophoblast cell invasion by up-regulating integrin β1 expression through ALK4-activated SMAD2/3-SMAD4 signaling pathway. Reference: (1) Bearfield et al., Eur J Endocrinol 2005;152:909–16. (2) Campbell et al., Hum Reprod 1995;10:1571–8.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".