Luo et al. demonstrated that cold exposure modulated the A. muciniphila abundance level in rats, thereby causing excessive secretion of TMAO which elevated the susceptibility to atrial fibrillation (AF) condition mainly through the enhanced infiltration of M1 macrophages in atria and increased protein expression of Casp1-p20 and cleaved GSDMD. The gene discussed is CASP1; the disease is atrial fibrillation.