Neuritic processes of multi-neuritic neurons display mixed axonal/dendritic phenotype.

<p>(A-C) Confocal images of control (A₁-C₁), a-SMN- (A₂-C₂) and FL-SMN- (A₃-C₃) silenced hippocampal neurons fixed at 8 DIV and co-labeled with the dendritic marker MAP2 (blue, C₁-C₃) and the axonal marker ankG (red, B₁-B₃), specifically staining the axon initial segment (AIS). (D₁-D₃) Merged images. Neurons treated with the control non-targeting siRNA displayed a unique AIS strongly labeled by ankG and different dendrites selectively labeled by MAP2. Staining selectivity was lost in multi-neuritic neurons silenced with a-SMN or FL-SMN, variably displaying axon and dendritic labeling in the same neuritic process. Arrowheads evidence ankG staining. (E) Stacked histograms showing the percent ratio of multi-neuritic neurons with normal vs. abnormal ankG and MAP2 distribution after control, a-SMN or FL-SMN silencing. Data are presented as mean ± SEM of three different experiments. Statistical analysis was performed by chi-square test (** p<0.01, ***p<0.001) among the three experimental groups (control, a-SMN siRNA and FL-SMN siRNA). Scale bar: 25 μm.