Landscape of pulmonary vein sleeves during atrial fibrillation by integrating single-cell sequencing and spatial transcriptomics

Background Atrial fibrillation (AF) is commonly sustained by ectopic triggers originating from the pulmonary vein (PV) sleeves. While pulmonary vein isolation is a cornerstone treatment, recurrence rates remain substantial due to an incomplete understanding of human PV pathophysiology. Objectives This study aims to define the pathophysiological landscape of human PV sleeves during AF. Methods Single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics were performed on PV sleeve tissues from patients with AF and sinus rhythm (SR). And the findings were further validated by neonatal mouse cardiomyocytes and patient samples. Results Our analysis revealed that profound cellular reorganization occurred during AF. Especially, an emergence of a unique pro-inflammatory cardiomyocyte subcluster was identified, which was located at the myocardial sleeve-vascular wall interface and exhibited a distinct cytokine and chemokine signature. Moreover, β-alanine metabolism was found to be downregulated within major cardiomyocyte populations during AF, accompanied with downregulation of contractile gene expression. Wheras β-alanine metabolism, dependent on the enzymatic activity of ALDH2, was required for the transcription factor ATF3 to restore contractile gene expression. And AF patients with the common ALDH2 loss-of-function variant (rs671) were observed with the significant characteristic of serum β-alanine metabolism impairment. Furthermore, computational ligand-receptor analysis revealed significant pro-inflammatory signaling interplay between cardiomyocyte subclusters and adjacent smooth muscle cells. Conclusions This study provides the first integrated cellular and spatial atlas of human PV sleeves during AF. Our results uncover a novel metabolic-transcriptional regulatory axis that drives contractile dysfunction cardiomyocytes during AF, mediated by β-alanine, ALDH2, and ATF3. And inflammatory cardiomyocyte remodeling acts as a key contributing to AF pathogenesis. These findings underscore the complex myocardial-vascular interactions within PV sleeves and point to novel therapeutic targets beyond conventional ablation strategies for AF treatment.Graph central