Fig. 2

APE1/Ref-1 inhibits LPS-induced iNOS expression and TNF-α secretion in primary cultured astrocytes. a Representative photomicrographs showing that LPS treatment induced iNOS expression in cultured astrocytes. Scale bar = 20 μm. b LPS increases iNOS expression and TNF-α secretion from cultured astrocytes in a time-dependent manner. Cells and media were harvested after treatment with LPS (100 nM) for the indicated times. c Western blot analysis for APE1/Ref-1 and iNOS was performed at 24 h on LPS-treated cells. Ectopic expression of APE1/Ref-1 using APE1/Ref-1 adenovirus (AdRef-1) inhibited LPS-stimulated iNOS expression. d Summarized data showing that APE1/Ref-1 inhibited LPS-induced iNOS expression (left) and TNF-α secretion (right). Data represent the mean ± standard error of mean (SEM; n = 4). ** p < 0.01 vs. non-transfected control cells; ^## p < 0.01 vs. β-galactosidase virus (Adβgal)-transfected control cells by a two-way anaysis of variance (ANOVA) followed by Dunnett’s test. e Reduced APE1/Ref-1 expression by short interfering RNA (siRNA; 100 pmol) significantly enhanced LPS-induced iNOS expression. f Summarized data showing that siRNA for APE1/Ref-1 (siRef-1) increased LPS-induced iNOS expression (left) and induced TNF-α secretion (right) in astrocytes. Data represent the mean ± SEM of four separate experiments. **, ^## p < 0.01 vs. non-transfected control cells and scrambled RNA (siCon) by two-way ANOVA, followed by Dunnett’s test, respectively