Abstract 5311: Proteolysis-resistant Collagen Drives Vascular Smooth Muscle Cell Senescence
Bibliographic record
Abstract
Senescence of vascular smooth muscle cells (SMCs) has recently been identified as a feature of atherosclerosis. However, the factors that lead to premature SMC senescence are not well understood. Plaque SMCs reside within a milieu of type I collagen fibrils that, over time, can undergo progressive intermolecular cross-linking rendering the collagen resistant to proteol-ysis. We hypothesized that vascular SMC longevity depends on the extent to which the surrounding type I collagen can be proteolytically edited. To test this, we studied mice with a targeted mutation of the 3/4 −1/4 collagenase cleavage site in type I collagen (Col1a1r/r). Mice harboring the Col1a1r/r mutation appeared normal up to 5 months of age but subsequently developed features of premature aging, including shortened lifespan (p<0.01), impaired weight gain (p<0.01), decreased adipose tissue content (p<0.01), and increased kyphosis (p<0.05), the latter two attributes quantified by micro CT imaging. Furthermore, SMCs in the aortic wall of aged, Col1a1r/r mice showed increased accumulation of reactive oxygen species, as assessed by hydroethidine incubation and nuclear fluorescence. To determine if collagenase-resistant collagen directly impacted SMC lifespan, primary human SMCs were cultured on collagen harvested from the tails of wild-type or Col1a1r/r mice. SMCs on mutant collagen displayed a 67% decrease in cumulative population doublings (p<0.01), which was associated with increased senescence-associated beta-galactosidase (SA-β-gal) activity (p<0.05) and increased p21 expression (p<0.05). Furthermore, stress-induced premature senescence, initiated by serum-deprivation and assessed by SA-β-gal activity and p21 expression, was also amplified in cells cultured on collagenase-resistant collagen. Conclusions: Collagenase-resistant type I collagen induces a premature aging-like syndrome in mice and accelerates both replicative and stress-induced senescence of vascular SMCs. These findings identify a novel, extracellular driver of vascular cell senescence that may underlie plaque instability in aging arteries.
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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 | 0.000 | 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 | 0.000 |
| 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".