Abstract P1027: Confocal And Mass Spectrometry-based Investigation Of REEP5 Depletion By AAV9 In The Mouse Heart
Bibliographic record
Abstract
The sarco(endo)plasmic reticulum (SR/ER) is an essential regulator of many key cellular processes, especially those that play a role in the development and progression of cardiac disease. However, many aspects of its structural organization remain poorly defined. Receptor Expression Enhancing Protein 5 (REEP5) is a cardiac enriched SR/ER membrane protein, which regulates organization of the highly differentiated SR/ER network and responses to stress. In zebrafish models, genetic knock-out of reep5 results in cardiac functional defects and reduced heart rate. Within the cardiomyocyte, depletion of Reep5 in vitro results in decreased muscle cell contraction, disrupted Ca 2+ signaling and SR/ER luminal vacuolization. For these studies, in vivo cardiac knock-down of Reep5 in the mouse was achieved using recombinant adeno-associated virus serotype 9 (rAAV9)-mediated gene delivery. Cardiac tissues or isolated cardiomyocytes were harvested at 7 days through to 4 weeks following knock-down, for biochemical and functional assessments. We observed that the largest significant change in REEP5 expression occurred 4 weeks post-rAAV9 injection, correlating to a 78% knock-down, observed by immunoblotting (unpaired t-test, p<0.0001, n=6-8). 5 weeks following knock-down, mice developed lethal cardiac dysfunction. To assess the biochemical changes induced by Reep5 knock-down, we have established an organelle-specific cardiac proteomic profile of the microsome, mitochondria and cytosol, using subcellular fractionation and mass spectrometry (nLC-ESI-MS-HCD-MS). Coupled with high resolution confocal microscopy and 3D mapping techniques, we have examined localization and expression patterns of key SR/ER and mitochondrial proteins, that have altered expression following knock-down of Reep5 at the myocyte-level. These findings provide a detailed understanding of the role that REEP5 plays in maintaining ER homeostasis, SR/ER structure, and general organelle integrity. By identifying the mechanistic significance of REEP5 expression in the heart, we can work to delineate underappreciated pathways in cardiac muscle development.
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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 | 0.000 |
| 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".