NR1H4 and Alzheimer disease: By clarifying their actions through receptors—such as SCFA-induced GPR43/GPR41 activation, indole-induced Aryl Hydrocarbon Receptor (AhR) activation, bile acid-induced FXR activation, and TMAO-induced NLRP3 inflammasome activation—we can enhance the precision of therapeutic targeting of the microbiota-GBA in AD [17, 47].