Functional Linkage between the Endoplasmic Reticulum Protein Hsp47 and Procollagen Expression in Human Vascular Smooth Muscle Cells
Bibliographic record
Abstract
Hsp47 is a heat stress protein that interacts with procollagen in the lumen of the endoplasmic reticulum, which is vital for collagen elaboration and embryonic viability. The precise actions of Hsp47 remain unclear, however. To evaluate the effects of Hsp47 on collagen production we infected human vascular smooth muscle cells (SMCs) with a retrovirus containing Hsp47 cDNA. SMCs overexpressing Hsp47 secreted type I procollagen faster than SMCs transduced with empty vector, yielding a greater accumulation of pro alpha1(I) collagen in the extracellular milieu. Interestingly, the amount of intracellular pro alpha1(I) collagen was also increased. This was associated with an unexpected increase in the rate of pro alpha1(I) collagen chain synthesis and 2.5-fold increase in pro alpha1(I) collagen mRNA expression, without a change in fibronectin expression. This amplification of procollagen expression, synthesis, and secretion by Hsp47 imparted SMCs with an enhanced capacity to elaborate a fibrillar collagen network. The effects of Hsp47 were qualitatively distinct from, and independent of, those of ascorbate and the combination of both factors yielded an even more intricate fibril network. Given the in vitro impact of altered Hsp47 expression on procollagen production, we sought evidence for interindividual variability in Hsp47 expression and identified a common, single nucleotide polymorphism in the Hsp47 gene promoter among African Americans that significantly reduced promoter activity. Together, these findings indicate a novel means by which type I collagen production is regulated by the endoplasmic reticulum constituent, Hsp47, and suggest a potential basis for inherent differences in collagen production within the population.
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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 | 0.001 | 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) | 0.000 | 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".