(A) Primary spinal cord cultures contained both GFAP positive astrocytes and NeuN positive neurons. GFAP, NeuN and TO-PRO®-3 triple labeling demonstrated that spinal cord cultures contain approximately 85% neurons, and 15% astrocytes. (B,C) Neurons in culture could also be immunostaining for ChAT, a marker for motor neurons. (D–G) Distribution of TDP-43 was restricted to the nucleus, while NAC1 was both nuclear and cytoplasmic. (H,I) Immunostaining for the 19s subunit of the proteasome appeared as bright puncta that were highly localized to the nucleus.