Figure 7
The ERK pathway plays a more important role than the Akt-mTOR pathway in the autophagy induced by elevated glucose levels.
The expression and phosphorylation of Akt and Erk were measured at the protein level in the control and glucose-treated HH10 chick heads. (A) Western blots showing the expression of phospho-Akt (p-Akt), total Akt, phosphor-Erk (p-Erk) and total Erk. (B,C) The relative expression of p-Akt and p-Erk compared to β-actin was measured. (D) HH9 chick embryonic neural tube tissues of the same size were incubated in vitro in the presence of either D-Glucose and D-Glucose with Rapamycin (mTOR inhibitor) or 3-MA (class III PI3K inhibitor), respectively. The upper panel displays bright-field images of the cranial neural crest cells that emigrated from the 48-hour primary cultures of neural tubes. The lower panel displays high magnification images from the sites indicated by the black dotted squares in the corresponding upper panel images, respectively. (E) The bar chart showing the comparison of migratory neural crest areas from the 48-hour cultured neural tubes between the D-Glc and D-Glc + 200 nM Rapamycin and D-Glc + 5 mM 3-MA treated groups (n = 6 in each group). (G) The bar chart showing the ratio of p-AKT/Akt protein expression in HEK293 cells between the control and high glucose-treated groups. ***P < 0.001 and **P < 0.01 indicate significant differences between the experimental and control embryos. Abbreviations: Con, control; L-Glc, L-Glucose; D-Glc, D-Glucose; RAPA: Rapamycin; 3-MA: 3-methyladenine. Scale bars = 500 μm in the upper panel and 100 μm in the lower panel of (D).
