Figure 7.

HDAC1 dephosphorylation is blocked by the calcineurin-specific inhibitors FK506 and cyclosporin A. A, Western blot analysis of phosphorylated S^{421, 423}-HDAC1 (P-HDAC1) and total HDAC1 from primary hippocampal neurons treated with Glut/TNFα in the presence or absence of calcineurin-specific inhibitors FK506 (1 μm) or CyA (2 μm). Quantification from three independent experiments and P-HDAC1 levels referred to total HDAC1. Data represent average ± SEM. Data were analyzed with one-way ANOVA with Bonferroni post hoc test, *p = 0.02 compared with the untreated control (the first bar). B, Calcineurin activity of neurons treated the same way as in A. Data are expressed as phosphate release (nmol) per micrograms total protein. Data represent average ± SEM. Data were analyzed with one-way ANOVA with Bonferroni post hoc test, ***p = 0.0002, **p = 0.0025, *p = 0.03 (FK506⁺), *p = 0.04 (CyA⁺) compared with the untreated control (the first bar), p > 0.05 (NS). C, Rat hippocampal neurons pretreated with FK506, followed by Glut/TNFα treatment for 1 h, were immunostained for HDAC1 or P-HDAC1 (green), SMI32 (red), NFH (gray), and DAPI. Scale bar, 20 μm. D, Percentage of NFH⁺ neurites colocalized with SMI32⁺ neurites was quantified in six to eight independent images (0.27 mm² per image) containing at least 400 DAPI⁺ cells. Data represent average ± SEM. Data were analyzed with one-way ANOVA with Bonferroni post hoc test, ***p < 0.0001 compared with the Glut/TNFα only group (the first bar), p > 0.05 (NS).