Complement activation products are elevated in cerebrospinal fluid, spinal cord and motor cortex of patients with amyotrophic lateral sclerosis (ALS) but are untested in models. We determined complement expression and activation in the SOD1 G93A mouse model of familial ALS (fALS). At 126days, C3 mRNA was upregulated in spinal cord and C3 protein accumulated in astrocytes and motor neurons. C3 activation products C3b/iC3b were localized exclusively on motor neurons. At the neuromuscular junction, deposits of C3b/iC3b and C1q were detected at day 47, before the appearance of clinical symptoms, and remained detectable at symptomatic stage (126days). Our findings implicate complement in the denervation of the muscle endplate by day 47 and destruction of the neuromuscular junction and spinal neuron loss by day 126 in the SOD1 G93A mouse model of fALS.
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This was a short paper that was well presented both on the immunology background as well as the work done. During the discussion, it was suggested that studying the dorsal horn would have been useful to understand the impact on the sensory pathway.