M1-type microglia have been shown to contribute to motor neuron degeneration in ALS by releasing proinflammatory cytokines such as tumor necrosis factor alpha (TNFα), interleukin 1 beta (IL-1β), interferon gamma (IFN-γ) and chemokines such as reactive oxygen species (ROS) and nitric oxide synthase (NOS) to initiate the immune response [4,50]. Here, TNF is linked to amyotrophic lateral sclerosis.