SOD1 and amyotrophic lateral sclerosis: The increase of TDP-43 protein expression, abnormal distribution in glial cells, negative correlation between the number of glial cells, and the amount of neuron cells in the spinal cord of SOD1 G93A transgenic mice, which was followed by an increase of neuron death (Figs. 2b and 6a, b), implies that overexpression of TDP-43 protein in both neurons and glial cells are a potential non-autonomous mechanism underlying the toxic factor of motor neuron degeneration in ALS.