TLR2 and cholestasis: Previous studies have shown that taurocholic acid could induce fetal arrhythmia associated with the cholestasis of pregnancy by signaling through M2-mAchR, thereby establishing the linkage between bile acids and acetylcholine receptor.37 Our novel observations revealed that free bile acid DCA could interact with M2-mAchR and then transactivate TLR2, a major pattern recognition receptor (PRR) that recognizes the conserved pathogen-associated molecular patterns (PAMPs), therefore triggers the downstream MAPKs and NF-kB signaling cascade to elicit the inflammatory response.