Single-nucleus transcriptomics of epicardial adipose tissue from female pigs reveals effects of exercise training on resident innate and adaptive immune cells

Coronary artery disease (CAD) is a leading cause of death in women. Although exercise mitigates CAD, the mechanisms by which exercise impacts epicardial adipose tissue (EAT) are unknown. We hypothesized that exercise promotes an anti-inflammatory microenvironment in EAT from female pigs. Female Yucatan pigs (n=7) were assigned to sedentary (SED) or exercise (EX) treatments and coronary arteries were occluded (O vs N) with an ameroid to mimic CAD. EAT was collected for bulk and single-nucleus transcriptomic sequencing (snRNA-seq). Clustering analysis revealed nine cell types in EAT with the fibroblast and macrophage populations predominantly from O-EX EAT and the T cell population predominantly from the N-EX EAT. Exercise upregulated G-protein coupled receptor, S100 family, and FAK pathways and downregulated the coagulation pathway. Exercise caused increased interaction between immune cells and endothelial and mesenchymal cells in the insulin-like growth factor pathway and between endothelial cells and other cell types except B cells in the platelet endothelial cell adhesion molecule pathway 1. Coronary occlusion impacted the largest number of genes in T and endothelial cells. Genes related to fatty acid metabolism were the most highly upregulated in non-immune cells from O-EX EAT. Sub-clustering of endothelial cells revealed that N-EX EAT separated from other treatments. In conclusion, exercise training increased interaction amongst immune and mesenchymal and endothelial cells in female EAT. Exercise was minimally effective at reversing alterations in gene expression in endothelial and mesenchymal cells in EAT surrounding occluded coronary arteries. These findings lay the foundation for future work focused on the impact of exercise on cell types in EAT from women. Animals were divided into two exercise (sedentary vs exercised) and two coronary artery (non-occluded and occluded) treatment groups. Surgeries were performed to place an ameroid constrictor (2.5-3.5 mm) around the proximal left circumflex artery. The ameroid constrictor progressively narrowed the artery and induced an inflammatory response resulting in total obstruction occurring at approximately two-three weeks post-operatively. Pigs recovered for eight weeks before the exercise training experimental regimen was initiated and maintained for 14 weeks. Speed and duration of the exercise training sessions were progressively increased so that during the last three weeks of training, animals ran at 4-5.5 mph for 60 minutes and at 6 mph for 5-15 minutes. Sedentary pigs maintained normal activity in their pens throughout the experimental protocol.