Hypoxia Downregulates MAPK/ERK but Not STAT3 Signaling in ROS-Dependent and HIF-1-Independent Manners in Mouse Embryonic Stem Cells

Figure 2

Effect of hypoxia on STAT3 and Akt (a) and ERK signaling (b) in wild-type and HIF-1α −/− ES cells. Analysis of STAT3 transcription activity (APRE-luc) in wild-type or HIF-1α −/− ES cultivated in complete medium (LIF) or LIF-free medium in normoxia or hypoxia (c). Effect of overexpression of mHIF1 and mHIF2 on ERK phosphorylation in wild-type ES cells (d). Analysis of HIF transcription activity (pt81/HRE-luc) induced by overexpression of mHIF-1 and mHIF-2 determined by luciferase reporter assay in wild-type ES cells (e). Effect of pharmacologically induced hypoxia on ERK phosphorylation in wild-type ES cells (f). The total level of β-actin was used as a loading control for western blot analyses. Data from luciferase assays are presented as mean + SEM from at least three independent experiments. Statistical significance was determined by one-way analysis of variance ANOVA and post hoc Bonferroni’s multiple comparison test ().

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