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. The gene discussed is OSM; the disease is atrial fibrillation.