Reduced neurite outgrowth in shTDP cells. A, Parental SH-SY5Y cells (Ctrl) or cells stably transduced with shRNA against TDP-43 (shTDP) were lysed, electrophoresed and Western blots sequentially probed with antibodies against TDP-43 (top panel) and HDAC6 (middle panel). Anti-GAPDH probing (bottom panel) confirmed equal loading. B, Schematic protocol for neurite outgrowth. Cells were primed with RA for 3d, after 3d RA-containing medium was changed. After another 3d medium was changed to serum-free supplemented with 50 ng/ml BDNF followed by further incubation. C, After each indicated interval, some cover slips were taken for fixation and staining with Alexa568-phalloidin. Size bars correspond to 10 μm. Quantifications were performed for the parameters D, number of neurites per cell, E, number of neurite branches per cell, F, total neurite length per cell and G, mean neurite length. All parameters were reduced in shTDP cells (light bars) compared to control cells (dark bars), either showing a trend (ns) or significantly (*p < 0.05, **p < 0.005).