BAs bind to TGR5 to increase AHR expression and promote transcription of ACOX 1 and CPT 1 A by triggering CAMP-ERK pathway and inhibit NLRP3 activity by triggering CAMP-PKA pathway, while AHR also inhibit activation of NLRP3, thus inhibiting hepatic steatosis. The gene discussed is AHR; the disease is fatty liver disease.