The bone morphogenetic protein receptor-1A pathway is required for lactogenic differentiation of mammary epithelial cells in vitro
Bibliographic record
Abstract
Bone morphogenetic proteins (BMPs) have been implicated in the control of proliferation, tissue formation, and differentiation. BMPs regulate the biology of stem and progenitor cells and can promote cellular differentiation, depending on the cell type and context. Although the BMP pathway is known to be involved in early embryonic development of the mammary gland via mesenchymal cells, its role in later epithelial cellular differentiation has not been examined. The majority of the mammary gland development occurs post-natal, and its final functional differentiation is characterized by the emergence of alveolar cells that produce milk proteins. Here, we tested the hypothesis that bone morphogenetic protein receptor 1A (BMPR1A) function was required for mammary epithelial cell differentiation. We found that the BMPR1A-SMAD1/5/8 pathway was predominantly active in undifferentiated mammary epithelial cells, compared with differentiated cells. Reduction of BMPR1A mRNA and protein, using short hairpin RNA, resulted in a reduction of SMAD1/5/8 phosphorylation in undifferentiated cells, indicating an impact on this pathway. When the expression of the BMPR1A gene knocked down in undifferentiated cells, this also prevented beta-casein production during differentiation of the mammary epithelial cells by lactogenic hormone stimulation. Addition of Noggin, a BMP antagonist, also prevented beta-casein expression. Together, this demonstrated that BMP-BMPR1A-SMAD1/5/8 signal transduction is required for beta-casein production, a marker of alveolar cell differentiation. This evidence functionally identifies BMPR1A as a potential new regulator of mammary epithelial alveolar cell differentiation.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.002 |
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".