Abstract 16472: Deciphering a Mechanistic Link Between Enhanced Late Sodium Current and Triggered Atrial Fibrillation Using Patient-specific and Gene-corrected Induced Pluripotent Stem Cell-derived Atrial Cardiomyocytes
Bibliographic record
Abstract
Introduction: Gain-of-function mutations in SCN5A, which encodes the cardiac sodium channel, have been linked with familial atrial fibrillation (AF). However, the mechanistic link between the late sodium current (I Na,L ) and triggered arrhythmia remains unclear. Hypothesis: To characterize the electrophysiological (EP) phenotype of gain-of-function AF-linked SCN5A mutations, elucidate the underlying cellular mechanisms using patient-specific and gene-corrected (GC) induced pluripotent stem cell-derived atrial cardiomyocytes (iPSC-aCMs). Methods: We generated iPSC-aCMs from two families carrying SCN5A mutations (E428K and N470K) and control subjects. Whole-cell patch clamp and multi-electrode arrays were recorded to assess the EP phenotypes of the atrial iPSC-CMs. We corrected the E428K iPSC-aCMs using CRISPR/Cas9 gene editing approach (isogenic control). Results: The SCN5A mutation lines displayed abnormal EP properties including increased beating frequency and irregularity with triggered beats characteristic of AF ( Fig. 1 ). E428K iPSC-aCMs displayed spontaneous arrhythmogenic activity with beat-to-beat irregularity ( Fig. 1 A-D ) with the prolonged APD ( Fig. 1 E-H ) associated with enhanced I Na,L ( Fig. 1 I-L ). In contrast, expression of SCN5A -E428K in heterologous expression system failed to show enhanced I Na,L . The gene-corrected E428K iPSC-aCMs normalized the aberrant EP phenotype. Gene expression profiling revealed differential expression of calcium and potassium channel homeostasis and nitric oxide mediated signal transduction which could result in EP remodeling of atrial CMs. Conclusions: Patient-specific and gene-corrected iPSC-aCMs exhibited striking ex-vivo EP phenotype of an AF-causing SCN5A gain-of-function mutation that produced minimal changes in-vitro . We established a mechanistic link between enhanced I Na,L , ion channel remodeling and nitric oxide signaling pathways, and triggered AF.
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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 | 0.001 | 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".