Two major results were obtained: (a) the HSPG and BMP signaling pathways were driven by ECs and FBs and PERIOSTIN was dominantly driven by ECs; (b) in AF, Mys cells were the origin of OSM ligands and FB3 was the predominant source of THY1 ligands, with partial contributions from SMC2. This evidence concerns the gene POSTN and atrial fibrillation.