Fig. 2: Left atrial (LA) myeloid cell immune landscape in atrial fibrillation (AF), analyzed by scRNA-seq.

A Uniform manifold approximation and projection (UMAP) of all myeloid cells (left), and re-clustered UMAP focusing on macrophages and monocytes (right) in LA tissues of patients with AF (n = 8). macs, macrophages; monos, monocytes; DCs, dendritic cells. B Dot plot displaying signature cell gene expression markers (SCGEMs) for each myeloid cell cluster. C Violin plot displaying SCGEMs for each macrophage cluster. D Gene Ontology (GO) terms showing the enriched biological process (BP) and molecular function (MF) of each macrophage sub-cluster. E sc-Metabolism analysis revealing the enriched metabolic and glycolysis or gluconeogenesis pathways of each macrophage sub-cluster, following UMAP analysis of macrophages and monocytes (in LA of patients with AF). F Velocity field projected onto the UMAP plots of macrophages and monocytes in LA and of blood samples (patients with AF). G CD68 staining of LA tissue of patients with AF. H Transmission electron microscopy (TEM) images of LA samples (patients with AF) (a–d): macrophages absorbing dysfunctional mitochondria; macrophage-like cells in the interstitial tissue of the muscular layer (e) and submucosa (f). CM, cardiomyocyte; MP, macrophage; CF, collagen fiber; Mt, mitochondria; Sm, sarcomere; EC, endothelial cell. Red arrows indicated exophers.