Activating AHR with endogenous ligands, such as FICZ or I3C, has been shown to alleviate cognitive deficits in an Alzheimer’s disease mouse model by upregulating the endogenous Aβ catabolic enzyme neprilysin.370 Moreover, AHR activated by microbiota ligands also plays a role in maintaining the integrity and function of the gut barrier, regulating immune responses. The gene discussed is AHR; the disease is Alzheimer disease.