Tauroursodeoxycholic Acid Confers Protection Against Oxidative Stress via Autophagy Induction in Retinal Pigment Epithelial Cells.

Tauroursodeoxycholic acid (TUDCA) has been shown to protect against oxidative damage in retinal pigment epithelial (RPE) cells. However, the mechanisms by which it mediates these protective effects have not been thoroughly investigated in the context of age-related macular degeneration (AMD) disease onset and progression. We measured LC3-II and p62 expression via Western blot and immunohistochemistry in RPE cells treated with H2O2, TUDCA, or a combination of both to measure autophagy induction. To determine autophagy flux, we measured the expression of LC3-II/LC3-I in RPE cells in the presence of bafilomycin via Western blot. To determine the mechanistic pathways of TUDCA-induced autophagy, we measured the protein expression of autophagy regulators (Atg5, Beclin-1, S6, AMPK, and Akt) via Western blot. We show that TUDCA-mediated autophagy induction confers protection of RPE cells against oxidative damage via mTORC1/mTORC2 independent pathways but depends on Atg5. Our work adds to the overall understanding of RPE cell homeostasis and highlights the role of TUDCA in maintaining RPE health.