Figure 2.

Molecular pathways implicated in the neuroprotective effects of bile acids in neurodegenerative disease models. Despite the relatively large structurally related group of bile acids, relatively few have been studied in neurodegenerative disorders. A major focus has been on apoptotic pathways and the PI3 kinase and AKT signaling pathway. Surprisingly, the primary signaling pathways through which bile acids act, TGR5, FXR, and FXR/RXR have received essentially no attention (designated by “?”), despite that retinoic acid is known to be a potent neurotrophic molecule.