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. 2017 Dec 12;4(6):ENEURO.0268-17.2017. doi: 10.1523/ENEURO.0268-17.2017

Figure 1.

Figure 1.

Activity-induced BDNF-dependent dendritic accumulation of hnRNP K in hippocampal neurons. A, B, Synaptic activity induces the accumulation of hnRNP K in dendrites of hippocampal neurons. Cultured hippocampal neurons (14-15 DIV) were stimulated or not with bicuculline (50 μM), 4-AP (2.5 mM), and glycine (10 μM), for 30 min. Where indicated, neurons were treated with the extracellular scavenger of TrkB ligands TrkB-Fc (1 μg/ml) for 30 min and were then stimulated or not with bicuculline in the presence of the scavenger. Cells were then fixed and immunostained for hnRNP K (red) and MAP2 (blue) (A). The integrated fluorescence intensity, area, and number of hnRNP K puncta in dendrites was analyzed using ImageJ software and represented per dendritic area (B). Results are normalized to control and are the mean ± SEM of 4–10 different experiments performed in independent preparations. Ctr, n = 108 cells; Bic, n = 97 cells; TrkB-Fc, n = 49 cells; Bic + TrkB-Fc, n = 52 cells. C, D, BDNF increases hnRNP K levels in neuronal dendrites. Cultured hippocampal neurons (14–15 DIV) were stimulated or not with BDNF (100 ng/ml) for 30 min. Where indicated, neurons were preincubated with the Trk receptor inhibitor SHN722 for 30 min, and the inhibitor was also present during the period of incubation with the neurotrophin. Cells were then fixed and immunostained for hnRNP K (red) and MAP 2 (blue) (C). The integrated fluorescence intensity, area, and number of hnRNP K puncta in dendrites was analyzed using ImageJ software and represented per dendritic area (D). Results are normalized to control and are the mean ± SEM of 4–10 different experiments performed in independent preparations. Ctr, n = 108 cells; BDNF, n = 53 cells; SHN722, n = 41 cells; BDNF + SHN722, n = 51 cells. Statistical analysis was performed by one-way ANOVA, followed by the Bonferroni’s multiple comparison test. **p < 0.01; ***p < 0.001. Scale bars: 5 μm. Extended Data Figure 1-1 shows that neuronal activity does not change total hnRNP K protein levels in cultured hippocampal neurons.