Figure 3Nuclear infolding triggered by SATB2 overexpression requires LEMD2. Analysis of the percentage of infolded nuclei in DIV10 hippocampal neurons upon Satb2 overexpression and Lemd2 knockdown. AAV-SATB2-transduced neurons (both non-transfected and scrambled siRNA-transfected, Scr) exhibited higher percentage of infolded nuclei compared to AAV-EGFP-transduced neurons. In contrast, LEMD2-depleted AAV-SATB2-transduced cultures showed similar percentage of infolded nuclei to AAV-EGFP-transduced neurons (n = 3-4 independent primary cultures; one-way ANOVA F3,11 = 30.982, p = 0.000011; Hochberg post hoc test, AAV-EGFP vs. AAV-SATB2 p = 0.0001, AAV-EGFP vs. AAV-SATB2 + Scr p = 0.0001, AAV-EGFP vs. AAV-SATB2 + siLemd2 p= 0.9999, AAV-SATB2 + Scr vs. AAV-SATB2 + siLemd2 p = 0.0001). Number of nuclei analyzed: 460 (AAV-EGFP), 466 (AAV-SATB2), 537 (AAV-SATB2 + Scr), 597 (AAV-SATB2+siLem2). Data are presented as mean ± SEM, ***p < 0.001 compared to AAV-EGFP; ###p < 0.001 compared to AAV-SATB2 + Scr.Activity-induced formation of nuclear infoldings is impaired in LEMD2-depleted cortical neurons. Bic-triggered AP bursting for 1 h caused a significant increase in the percentage of infolded nuclei in cortical neurons transduced with AAV-scrambled but not with AAV-shLemd2 virus (n = 5 independent primary cultures, two-way ANOVA, F1,16 = 8.35, significant interaction p = 0.0107, simple main effects analysis: AAV-scrambled-transduced cultures, Bic-treated vs untreated p = 0.0049, AAV-shLemd2-transduced cultures, Bic-treated vs untreated p > 0.99, adjustment for multiple comparisons: Bonferroni). Data are presented as mean ± SEM, **p < 0.01 compared to NBQX-treated cultures.LEMD2 is required for the nuclear envelope infoldings of CA1 pyramidal neurons in vivo. Top panel: representative confocal images (z-axis-projected stack) of Lamin B2/DAPI-stained coronal brain sections from wild-type mice after stereotaxic injection of AAV-shRNA viruses (AAV-shLemd2-mCherry or AAV-scrambled-mCherry) into the dorsal hippocampus. Merged, colocalization of the three signals. Scale bars: 50 μm. Middle panel: higher magnification images of AAV-shLemd2-transduced CA1 pyramidal neurons. Arrows show examples of mCherry-positive nuclei that are devoid of nuclear infoldings, whereas stars denote non-transduced infolded nuclei. Lower panel: higher magnification images of AAV-scrambled siRNA-transduced CA1 pyramidal neurons. Arrows show examples of infolded, mCherry-positive nuclei; stars denote infolded, non-transduced neurons. Scale bars (middle and lower panels): 10 μm.Analysis of the percentage of infolded nuclei in DIV10 hippocampal neurons upon SATB2 overexpression and Vps4a/ Vps4b knockdown. AAV-SATB2-transduced neurons (non-transfected or scrambled siRNA (Scr)-transfected) exhibited higher percentage of infolded nuclei compared to AAV-EGFP-transduced neurons. In contrast, VPS4-depleted AAV-SATB2-transduced cultures showed similar number of infolded nuclei to AAV-EGFP-transduced neurons (n = 4 independent primary cultures, one-way ANOVA followed by Tuckey post hoc test, F3,11 =15.866, p = 0.00026, AAV-EGFP vs. AAV-SATB2 p = 0.0104, AAV-EGFP vs. AAV-SATB2 + Scr p = 0.0028, AAV-EGFP vs. AAV-SATB2 + siVps4 p = 0.605, AAV-SATB2 + Scr vs. AAV-SATB2 + siVps4 p = 0.0007). Number of nuclei analyzed: 594 (AAV-EGFP), 657 (AAV-SATB2), 612 (AAV-SATB2 + Scr), 428 (AAV-SATB2 + siVps4). Data are presented as mean ± SEM, **p < 0.01 compared with AAV-EGFP; ###p < 0.001 compared with AAV-SATB2 + Scr.Activity-induced formation of nuclear infoldings is impaired in VPS4-depleted cortical neurons. Upon AP bursting, the percentage of infolded nuclei was increased in non-transfected cultures and in cultures transfected with scramble siRNA (Scr) but not with siVps4 (n = 3-4 independent primary cultures, one-way ANOVA followed by Tuckey post hoc test, F3,8 = 90.525, p = 1.63E-06, Bic-treated vs NBQX-treated p = 0.000012, Scr Bic-treated vs NBQX-treated p = 0.000052, siVps4 Bic-treated vs NBQX-treated p = 0.396, siVps4 Bic-treated vs Scr Bic-treated p = 0.000015). Number of analyzed nuclei: 474 (NBQX), 456 (Bic), 409 (Bic + Scr), 383 (Bic + siVps4). Data are presented as mean ± SEM, ***p < 0.001 compared to NBQX-treated, ###p < 0.001 compared to Scr Bic-treated.