Hyperosmotic Stress Initiates AMPK-Independent Autophagy and AMPK- and Autophagy-Independent Depletion of Thioredoxin 1 and Glyoxalase 2 in HT22 Nerve Cells

Figure 4

mTOR inhibition and autophagy induction were equally observed in wild-type (WT) and AMPK-deficient (AMPK-KO) mouse embryonic fibroblasts (MEFs) exposed to hyperosmotic stress. Representative images of blots probed for autophagic markers p62 and LC3 and for the mTOR pathway. Decreased p62 and an increased LC II/LC3 I ratio are markers of increased autophagy, which can be observed in both WT and AMPK-KO MEFs (compare to Figure 3(c)). The mTOR substrate, S6 kinase (P70S6K), presented lower levels of phosphorylation under hyperosmotic stress, indicating lower mTOR activity. The same can be concluded when evaluating the phosphorylated form of S6 ribosomal protein (pS6), the P70S6K substrate, which decreased at 1 and 3 hours. Images were obtained from three independent experiments.