Silencing of both ATF4 and PERK inhibits cell cycle progression and promotes the apoptosis of differentiating chondrocytes
Bibliographic record
Abstract
In the current study, we demonstrate that the silencing of protein kinase R (PKR)-like endoplasmic reticulum (ER) kinase (PERK) and activating transcription factor 6 (ATF4) (using small interfering RNA expression constructs) inhibits the chondrocyte cell cycle and proliferation in vitro and ex vivo. The silencing of PERK alone using siRNA against PERK (siPERK) led to arrest in the G1 phase, it decreased the number of cells in the S phase, and delayed progressoin to the G2‑M phase. Co-transfection with siRNA against ATF (siATF4) led to a more profound inhibitory effect on cell cycle progression. Moreover, transfection with siPERK was associated with enhanced endoplasmic reticulum (ER) stress‑induced apoptosis during bone morphogenetic protein 2 (BMP2)‑induced chondrogenesis, and transfection with siATF4 exacerbated ER stress‑related cell death. Data from flow cytometry (FCM), immunohistochemistry and TUNEL assays supported these findings in vitro and ex vivo. As shown by our results, the combined effect of the silencing of ATF4 and PERK led to the activation of an ER stress‑specific caspase cascade in the cartilage tissue. On the whole, these findings reveal a new crucial combined effect of the silencing of PERK and ATF4 in modulating ER stress‑mediated apoptosis during chondrocyte differentiation and proliferation.
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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".