Granzyme B promotes matrix metalloproteinase‐1 (<scp>MMP</scp>‐1) release from gingival fibroblasts in a <scp>PAR1</scp>‐ and Erk1/2‐dependent manner: A novel role in periodontal inflammation
Bibliographic record
Abstract
Abstract Objective To gain insights into how proteases signal to connective tissues cells in the periodontium. Background The connective tissue degradation observed in periodontitis is largely due to matrix metalloproteinase (MMP) release by gingival fibroblasts. Granzyme B (GzmB) is a serine protease whose role in periodontitis is undefined. Methods Human gingival crevicular fluid (GCF) samples were obtained from sites with periodontal disease and healthy control sites. GzmB was quantified in the GCF ([GzmB] GCF ) by ELISA. Gingival fibroblasts (GF) were cultured in the presence or absence of recombinant GzmB. Culture supernatants were analyzed by ELISA to quantify GzmB‐induced release of interstitial collagenase (MMP‐1). In some experiments, cells were pre‐treated with the inhibitor PD98059 to block MEK/ERK signaling. The protease‐activated receptor‐1 (PAR‐1) was blocked with ATAP‐2 neutralizing antibody prior to GzmB stimulation. Systemic MMP‐1 levels were measured in plasma from wild‐type ( WT ) and granzyme‐B‐knockout ( GzmB −/− ) mice. Results The [GzmB] GCF in human samples was ~4–5 fold higher at sites of periodontal disease (gingivitis/periodontitis) compared to healthy control sites, suggesting an association between GzmB and localized matrix degradation. GzmB induced a ~4–5‐fold increase in MMP‐1 secretion by cultured fibroblasts. GzmB induced phosphorylation of Erk1/2, which was abrogated by PD98059. GzmB‐induced upregulation of MMP‐1 secretion was also reduced by PD98059. Blockade of PAR‐1 function by ATAP‐2 abrogated the increase in MMP‐1 secretion by GF. Circulating MMP‐1 was similar in WT and GzmB −/− mice, suggesting that GzmB's effects on MMP‐1 release are not reflected systemically. Conclusion These data point to a novel GzmB‐driven signaling pathway in fibroblasts in which MMP‐1 secretion is upregulated in a PAR1‐ and Erk1/2‐dependent manner.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.012 | 0.008 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.006 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 teacher head, 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".