Abstract 12040: JAK-STAT Signalling and the Atrial Fibrillation-Promoting Fibrotic Substrate: Pathogenic Role and Possible Therapeutic Target
Bibliographic record
Abstract
Introduction: Left atrial (LA) fibrosis is an important feature of the atrial fibrillation (AF) substrate. The JAK-STAT system, activated by platelet derived growth factor (PDGF), contributes to cardiac remodeling but its role in AF is unknown. Here, we investigated the participation of the JAK-STAT system in LA fibrosis development. Methods: Heart failure (HF) was induced in dogs by ventricular tachypacing (VTP, 240 bpm) and in mice subjected to myocardial infarction (MI). Protein and mRNA expression were measured in freshly isolated LA fibroblasts (FBs) by Western blot and qPCR. Mice received S3I-201,a selective STAT3 inhibitor, or vehicle control (CTL) by osmotic minipump for 2 weeks post MI. Results: HF dogs developed progressive LA-selective fibrosis and AF susceptibility beginning at 1 wk VTP. HF increased JAK2 mRNA expression in LA FBs from 1 wk VTP (1.4-1.5 fold**, **P<0.01). Phosphorylated JAK2 and STAT3 protein increased in HF atrial tissue by 2.5** and 2.9* fold (*p<0.05) respectively. Upstream signalling through PDGF was also enhanced by HF: PDGF A/C/D upregulated by 2.2-3.5*** fold (***p<0.001); PDGFR β upregulated by 2.3** fold. PDGF stimulation of CTL dog LA FBs increased TGFβ1, TGFβ receptor 2, STAT3, collagen 1α1 and collagen 3α1 expression (by 1.2-2.3 fold***). These effects were abolished by S3I-201 in a dose dependent manner (by 79%*** at 100 μM). In vivo S3I-201 treatment (Figure) decreased LA fibrosis (by 60%***), LA dimension at end systole (by 11%*) and P wave duration (by 31%***). MI-induced LV dilation and contractile dysfunction were not affected by S3I-201. Conclusions: HF activates the LA JAK-STAT system via enhanced PDGF signalling. JAK-STAT inhibition reduces the profibrotic effects of PDGF stimulation on canine FBs in vitro and attenuates LA fibrosis and electrical remodeling post MI in mice. These results suggest that the JAK/STAT pathway plays an important role in LA fibrogenesis and is a potential target for LA fibrosis prevention in man.
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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) | 0.001 | 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 | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.012 | 0.003 |
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".