Abstract 11940: Mineralocorticoid Receptor Dysregulation by MicroRNA-135a in Bradycardic Arrhythmogenic Remodeling
Bibliographic record
Abstract
Introduction: Complete atrioventricular block (CAVB) causes arrhythmogenic remodeling and increases the risk of Torsades de Pointes (TdP) arrhythmias. MicroRNAs (miRs) are key regulators of gene expression that contribute to cardiac remodeling. Here, we assess microRNA changes after CAVB and their potential significance in arrhythmogenic cardiac remodeling. Methods: CAVB was induced in mice via His bundle ablation. Expression of miRs was evaluated by pan-microRNA microarray with qPCR confirmation on samples from controls and at 24 hrs and 4 wks post-CAVB. Arrhythmias were detected by continuous monitoring. MicroRNA target prediction algorithms were used to identify potential target genes. Biological confirmation of targets was by luciferase assay and overexpression (OE) studies in HEK and H9c2 cells respectively. Results: TdP occurred within 24 hrs in 6/17 CAVB mice, vs no controls. Ventricular tachyarrhythmia episodes were frequent at 4 wks CAVB (212±83 per 24 hrs) and were not seen in controls. CAVB was followed by increased left ventricular (LV) dimension (by 31%, ***p<.001), LV mass (by 33%, *p<.05) and LV fractional shortening (by 33%*) at 4 wks. Of >400 miRs assayed, only miR-135a was altered at 24 hrs (downregulated by 96%***, Fig. A), with 70% decrease at 4 wks. TargetScan predicted miR-135a regulation of the mineralocorticoid receptor (MCR), encoded by the NR3C2 gene. miR-135a OE suppressed NR3C2 3’UTR reporter activity 3.2-fold* (n=5, Fig. B). miR-135a OE did not affect NR3C2 mRNA (Fig. C) but significantly reduced NR3C2 protein expression (n=4, Fig. D). Coexpression with anti-miR-135a eliminated the NR3C2 downregulating effect of miR-135a OE. Conclusions: The mineralocorticoid receptor, encoded by the NR3C2 gene, is translationally regulated by miR-135a, a microRNA that is downregulated in the heart following CAVB in mice. These results implicate miR-135a/mineralocorticoid modulation in arrhythmogenic ventricular remodeling caused by CAVB.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
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".