ASBMR 30th Annual Meeting SA001–SA572
Bibliographic record
Abstract
In order to examine if autogenous BMP-2 expression is necessary for the osteogenic differentiation of marrow stromal cells, BMP-2 expression was inhibited using lentiviral transfection of a BMP2 shRNA.Inhibition of BMP2 expression decreased the expression of markers of terminal osteoblasts (osteocalcin, Runx2, osterix, APase activity, and mineral deposition), while the expression of transcription factors (Sox 9 and Msx2) that are seen in skeletal lineage progenitors were not effected.Rescue of osteogenic differentiation by the exogenous addition of either BMP7 or BMP2 recovered the levels of expression of osterix and APase and enhanced Sox9 and Msx2.However, BMP7 did not recover the expression of Runx2 and only partially recovered mineral deposition while the exogenous addition of BMP2 recovered all of these phenotypic properties.The effect of the loss of BMP2 expression on bone formation after marrow ablation lead to 80% loss of mineralized bone formation as assayed by microCT at day seven after surgery.Assay of same set of mRNAs as examined in vitro showed transient ~2 fold increase of Sox9 at day three after surgery in the shRNA BMP2 samples while at day seven osterix, Runx2, osteocalcin and Sox9 all showed ~50 to ~80% inhibition compared to expression in the NT (scrambled) treated samples.Interestingly, Msx2 showed ~10 fold elevation expression at seven days post surgery.Immunohistological examination of the cell populations found in the meduallary space three days after surgery with antibodies for CD146 and Sox9, showed equal numbers of cells expressing these skeletal stem markers in both control and shRNA treated specimens.These results demonstrate that: 1) BMP-2 is a central morphogenetic factor for the post natal osteogenic differentiation: 2) BMP2 does not effect the initial recruitment or expansion of skeletal stem cells in vivo: 3) Both BMP2 and BMP7 can both induce osterix and this transcription factor can promote ostegenic differentiation: 4) Expression of Runx2 is dependent on BMP2: 5) Both osterix and Runx2 are needed to fully promote osteogenic development.Figure 1 MicroCt assessment of endosteal bone formation in response to surgical marrow ablation.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.002 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.467 | 0.464 |
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".