Chondrocyte‐produced TGFβ regulates early stages of osteoblast differentiation
Bibliographic record
Abstract
Our lab has shown that hypertrophic chondrocytes produce large quantities of activated TGFβ. To determine whether TGFβ produced and activated by hypertrophic chondrocytes promotes osteoblast differentiation, hypertrophic chondrocytes were isolated from avian sterna and placed in serum‐free alginate cultures. Pre‐osteoblasts (HOB‐03‐C5; POB) and early mature osteoblasts (HOB‐03‐CE6; EMOB) were treated for 2, 6 and 12 hours with conditioned media (CM) obtained from day 5 chondrocyte cultures. A transient stimulation of osteopontin (OP) expression was noted after 6 hours treatment in both osteoblast populations. Expression of osterix (OSTX) was inhibited as early as 2 hours CM treatment in both osteoblast populations. Inclusion of pan‐specific neutralizing antibody to TGFβ (nAb) in the 6hour treatment with CM returned expression of OP in the POBs and OSTX expression in both POB and EMOB to control levels. Chondrocyte‐produced TGFβ was depleted from day 5 chondrocyte CM by passage over a strep‐avidin micro‐bead column containing biotin‐labeled polyclonal antibody to TGFβ. OP expression in both OB populations was returned to control; however, OSTX expression remained unchanged. Since nAb blocks activity of all TGFβ present, but depletion of the CM only removed chondrocyte‐produced TGFβ, these data suggest that OB‐specific gene responses at the chondro‐osseous border are highly dose dependent and indicate at least a partial role for chondrocyte‐produced TGFβ in early OB 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) | 0.000 | 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) | 0.001 | 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".