The effects of contractile activity on mitochondrial adaptations in PGC‐1alpha‐deficient muscle cells
Bibliographic record
Abstract
PGC‐1α is a well established mediator of mitochondrial content and function in skeletal muscle. However, the essentiality of the coactivator for mitochondrial biogenesis (MB) in response to chronic contractile activity (CCA) is still in question. Thus, we depleted skeletal muscle C2C12 cells of PGC‐1α using siRNA, then stimulated the myotubes to induced MB. A 60% reduction in PGC‐1α using siRNA resulted in a compensatory increase in AMPK phosphorylation, but had no effect on the mRNA expression of PGC‐1β, PRC, NRF‐1/2 or YY1, proteins that may have served to compensate for low PGC‐1α levels. In response to CCA, we found that a normal induction of PGC‐1α in response to CCA was required to observe the typical changes in MB, as revealed by attenuated increases in COX activity (p<0.05) and mitochondrial immunofluorescence. Decreased levels of PGC‐1α also reduced the CCA‐evoked increases in COXIV. However, PGC‐1α was not necessary for the CCA‐induced changes of all mitochondrial proteins since Tfam and cytochrome c displayed normal increases, regardless of attenuated PGC‐1α levels. Thus, PGC‐1α is necessary for the normal induction of mitochondrial biogenesis, and the coactivator likely functions with parallel pathways to mediate increases in mitochondrial proteins with CCA.
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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".