Absence of tumor necrosis factor-α does not affect motor neuron disease caused by superoxide dismutase 1 mutations

Abstract

An increase in the expression of the proinflammatory cytokine tumor necrosis factor α(TNF-α) has been observed in patients with amyotrophic lateral sclerosis (ALS) and in the mice models of the disease. TNF-α is a potent activator of macrophages and microglia and, under certain conditions, can induce or exacerbate neuronal cell death. Here, we assessed the contribution of TNF-α in motor neuron disease in mice overexpressing mutant superoxide dismutase 1 (SOD1) genes linked to familial ALS. This was accomplished by the generation of mice expressing SOD1 G37R or SOD1G93A mutants in the context of TNF-α gene knock out. Surprisingly, the absence of TNF-α did not affect the lifespan or the extent of motor neuron loss in SOD1 transgenic mice. These results provide compelling evidence indicating that TNF-α does not directly contribute to motor neuron degeneration caused by SOD1 mutations. Copyright © 2006 Society for Neuroscience.