SATB2 determines nuclear envelope structural plasticity in neurons Representative images of z-axis projected stacks of confocal images of hippocampal neuronal nuclei immunostained for Lamin B2.Figure 2Representative images of z-axis projected stacks of confocal images of hippocampal neuronal nuclei immunostained for Lamin B2. Examples of spherical and infolded nuclei are shown. Scale bars: 3 μm. Activity-induced formation of nuclear infoldings is abolished in SATB2-defficient hippocampal neurons. Bic-induced AP bursting for 1 h caused a significant increase in the percentage of infolded nuclei in DIV10 hippocampal cultures derived from Satb2flx/flx mice but not from Satb2flx/flx::Nes-Cre mice (Satb2NesCre) (n = 6 independent primary cultures, two-way ANOVA, F1,20 = 9.51, significant interaction p = 0.0058, simple main effects analysis, Satb2flx/flx cultures, Bic-treated vs untreated p = 0.0000043, Satb2NesCre cultures, Bic-treated vs untreated p > 0.05, adjustment for multiple comparisons: Bonferroni, number of analyzed nuclei: Satb2flx/flx cultures, untreated - 680, Satb2flx/flx cultures, Bic-treated - 711, Satb2NesCre, untreated - 755, Satb2NesCre, Bic-treated - 720). Data are presented as mean ± SEM, ***p < 0.001. Activity-induced formation of nuclear infoldings is impaired in SATB2-deficient cortical neurons. DIV14 cortical cultures form Satb2flx/flx and Satb2NesCre mice were silenced with NBQX for 1 h followed by stimulation with Bic for 1 h. The percentage of infolded nuclei following AP bursting was increased in control Satb2flx/flx cultures but not in SATB2-deficient cultures (n = 3-4 independent primary cultures, two-way ANOVA, F1,10 = 39.124, significant interaction p = 0.000094, simple main effects analysis, Satb2flx/flx cultures: Bic-treated vs NBQX-treated p = 7.66E-07, Satb2NesCre cultures: Bic-treated vs NBQX-treated p > 0.05, adjustment for multiple comparisons: Bonferroni, number of analyzed nuclei: Satb2flx/flx cultures, NBQX - 606, Satb2flx/flx cultures, Bic - 910; Satb2NesCre cultures, NBQX -604, Satb2NesCre cultures, Bic - 835). Data are presented as mean ± SEM, ***p < 0.001. Confocal images (z-axis-projected stacks) of Lamin B2 stained neuronal nuclei from the CA1 pyramidal cell layer of adult Satb2flx/flx and Satb2flx/flx::CamK2a-Cre (Satb2CamkCre) mice. Scale bars: 10 μm. Analysis of the percentage of infolded nuclei in the hippocampus of Satb2flx/flx mice vs Satb2CamkCre mice. In Satb2flx/flx mice, the number of infolded nuclei was significantly higher in the CA1 area compared to the CA3 area (p = 0.000001) and DG (p = 1.8 E-12). In Satb2CamkCre mice, the number of infolded nuclei in the CA1 area was significantly reduced compared to the corresponding number in littermate controls (p = 1.9 E-09). No significant differences were observed in this number in the CA3 and DG between Satb2CamkCre mice and floxed controls (n = 4 mice, two-way ANOVA, significant interaction, F2,18 = 47.81, p = 0.00001, simple main effects analysis, CA1 area, Satb2flx/flx vs CKO mice p = 1.9 E-09, CA3 area, Satb2flx/flx vs CKO mice p = 0.909, DG, Satb2flx/flx vs CKO mice p = 0.262, adjustment for multiple comparisons: Bonferroni). Number of analyzed nuclei: Satb2flx/flx mice: 469 (CA1), 225 (CA3), 665 (DG); Satb2CamkCre: 508 (CA1), 224 (CA3), 575 (DG). Data are presented as mean ± SEM, ***p < 0.001. Analysis of the percentage of infolded nuclei in the CA1 pyramidal cell layer of Satb2CamkCre mice vs. littermate controls after stereotaxic injections of AAV-SATB2-V5 or AAV8-EGFP. Viral delivery of SATB2 resulted in restoration of the number of infolded nuclei in the CA1 pyramidal cell layer of Satb2CamkCre mice (n = 3-5 mice, one-way ANOVA followed by Hochberg post hoc test, F2,9 = 33.1, Satb2CamkCre::AAV-SATB2 vs. Satb2flx/flx::AAV-EGFP, p = 0.0012; Satb2flx/flx::AAV-EGFP vs. Satb2CamkCre::AAV-EGFP, p = 0.00008, Satb2flx/flx::AAV-EGFP vs. Satb2CamkCre::AAV-SATB2, p = 0.072). Number of analyzed nuclei: 388 (Satb2flx/flx::AAV-EGFP), 560 (Satb2CamkCre::AAV-EGFP), 546 (Satb2CamkCre::AAV-SATB2). Data are presented as mean ± SEM, ***p < 0.001 compared to Satb2flx/flx::AAV-EGFP, ##p < 0.01, compared to Satb2CamkCre::AAV-EGFP.