COL2A1 and atrial fibrillation: Displayed high expression of SFRP1, BIRC5, CYTL1, ESM1 and CCNB2 genes in AF cells and COL2A1, DSC3, COL9A3, COL11A1, and ANGPTL7 in NP cells. Identified signature transcription factors for AF (FOXM1) and NP (KDM4E)