Phenotype-Specific Effect of Protein Kinase A on Skeletal Muscle Induction of Hsp70 Following Exercise
Bibliographic record
Abstract
Heat shock protein 70 (Hsp70) has been found to play cyto-protective roles in both cardiac and skeletal muscle. To this point, little attention has been paid to the signaling mechanisms involved in expression of Hsp70 in skeletal muscle. PURPOSE: To characterize the role of protein kinase A (PKA) in regulation of the Hsp70 response to endurance exercise in skeletal muscle. METHODS: Twenty-eight 12 week-old male Sprague-Dawley rats were divided into sham (5 % DMSO; n=14) and PKA-inhibited (0.36 mg/kg H-89 in 5% DMSO; n=14) groups and run on a motor-driven treadmill for 60 min at 30 m/min on a 2% grade. Exercised (EX) animals were subsequently killed at 30 min (Hsp70 mRNA evaluated by RT-PCR; n=7) or 24 h (western blot analysis of Hsp70; n=7) post-exercise and portions of the white vastus (WV) and soleus (Sol), representing muscles with different recruitment patterns and fiber-type profiles, were taken and evaluated compared to appropriate non-exercised controls (CON; n=7 per group). RESULTS: All data are expressed as means ± SE. Hsp70 protein (% of control standard) was increased (P<0.05) in sham-injected rats in WV (CON: 30.30 ± 4.14, EX: 113,1 ± 11.81) but not Sol (CON: 152.42 ± 23.62, EX: 134.81 ± 32.33) following exercise. PKA inhibition suppressed this response in WV (EX: 25.01 ± 6.26). However, Hsp70 mRNA (corrected to β-Actin mRNA), was significantly increased (P<0.05) in both muscles (CON: 5.69 ± 0.59, EX: 26.43 ± 10.55 for WV; CON: 3.22 ± 0.44, EX: 56.87 ± 14.37 for Sol) following exercise and this increase was unaffected by PKA inhibition. CONCLUSIONS: Exercise selectively increases the relative content of Hsp70 in a muscle-specific, PKA-dependent manner. In skeletal muscle, the exercise-induced increase in Hsp70 appears to be under both transcriptional and translational control and PKA appears to regulate this process at the level of translation. Supported by NSERC grant # 8170–00 and Ontario Graduate Scholarship funding
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.002 | 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 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".