Figure 1Expression of Tardbp, total Sort1 and exon 17b Sort1 mRNAs quantified by Q-PCR in primary hippocampal neurons infected with either scrambled or Tardbp shRNA lentiviruses. Values were first normalized to Gapdh mRNA levels, then plotted as average ± SEM relative to the value of scrambled shRNA (N=3 independent experiments; n=3 wells per condition in each experiment). ***, p<0.001. Data information: Results are presented as average ± standard error of the mean (SEM). All statistical tests were performed using 2-way ANOVA with Sidak post hoc analysis.Western blots of cell lysates and culture supernatants showing TDP-43 and Sortilin expression in primary hippocampal neurons infected with scrambled or Tardbp shRNA lentiviruses. Uninfected cultures were used as an additional control. β-actin immunoblotting and Coomasise Blue staining were used to control equal loading of lysates and supernatants, respectively. Molecular weights are indicated in kDa. Data information: Results are presented as average ± standard error of the mean (SEM). All statistical tests were performed using 2-way ANOVA with Sidak post hoc analysis.Representative photomicrographs of cultured hippocampal neurons infected with scrambled or Tardbp shRNA lentiviruses, immunolabled for BDNF (green), SCG2 (red) and counterstained with DAPI (blue) in orthogonal views (dashed lines) showing colocalization of BDNF and SCG2 in the soma (white arrows).Colocalization between BDNF and SCG2-positive vesicles expressed as percentage of total BDNF immunoreactivity ±SEM in cultured hippocampal neurons infected with scrambled or Tardbp shRNA lentiviruses (N=3 independent experiments, n>50 individual cells per condition in each experiment). **, p<0.01. Data information: Results are presented as average ± standard error of the mean (SEM). All statistical tests were performed using 2-way ANOVA with Sidak post hoc analysis.Colocalization between BDNF and SCG2-positive vesicles in hippocampal neurons infected with scrambled or Tardbp shRNA lentiviruses together with either EGFP or Sortilin rescue viruses. Histogram bars show average ± SEM BDNF/SCG2 colocalization expressed as percentage of total BDNF immunoreactivity (N=3 independent experiments, n>50 individual cells per condition in each experiment). **, p<0.01. Data information: Results are presented as average ± standard error of the mean (SEM). All statistical tests were performed using 2-way ANOVA with Sidak post hoc analysis.BDNF secretion induced by KCl treatment assessed by in-situ BDNF ELISA in cultured hippocampal neurons infected with scrambled or Tardbp shRNA lentiviruses. Histogram bars show average ± SEM BDNF levels normalized to a standard curve (N=3 independent experiments; n=3 wells per condition in each experiment). *, p<0.05; ***, p<0.001. Data information: Results are presented as average ± standard error of the mean (SEM). All statistical tests were performed using 2-way ANOVA with Sidak post hoc analysis.BDNF secretion in cultured hippocampal neurons infected with scrambled (left) or Tardbp (right) shRNA lentiviruses together with either EGFP, Sort1 shRNA or Sortilin rescue viruses. Histogram bars show average ± SEM BDNF levels normalized to a standard curve (N=3 independent experiments; n=3 wells per condition in each experiment). ***, p<0.001. Data information: Results are presented as average ± standard error of the mean (SEM). All statistical tests were performed using 2-way ANOVA with Sidak post hoc analysis.