Figure 1.

TDP-43-enriched RNA granules colocalize with stress granules. A, Representative images from a primary hippocampal neuron expressing EGFP WT TDP-43 and RFP-TIA-1. Endogenous MAP2 (blue) was detected by immunocytochemistry. Scale bar, 10 μm. Higher magnification of the boxed images of the dendrite showed that dendritic WT TDP-43-enriched RNA granules colocalize with stress granules. Scale bars, 2 μm. B, Representative primary hippocampal neuron coexpressed EGFP-WT TDP-43 and RFP-G3BP. WT TDP-43-enriched RNA granules colocalize with stress granules in neuronal soma but not neuronal processes. Arrows point to colocalized RNA granules. Scale bar, 10 μm. C, Coexpression of EGFP-WT TDP-43 and RFP-Dcp1a in a representative primary hippocampal neuron. Scale bar, 10 μm. Higher magnification of the boxed images showed WT TDP-43-enriched RNA granules express adjacent to P-bodies. Scale bars, 2 μm. D, Fluorescent immunocytochemistry was applied to detect endogenous WT TDP-43 (green) and TIA-1 (red). In neuronal process from a representative DIV 20 hippocampal neuron, higher-magnification images were captured and show that some WT TDP-43-enriched RNA granules contain TIA-1. Scale bars, 10 μm. E, Expression of TDP-43 in MN iPSCs from neurologically normal (Ctrl) and ALS human lines, with quantification on the right. Arrows point to TDP-43 granules. Scale bar, 10 μm. F, Immunoblot of TDP-43 from MN iPSCs from control and familial ALS (G298S) donors. Increased levels of multimeric, insoluble TDP-43 was present in in the familial ALS line at 21 and 28 d of culture after differentiation.