TNF and neurodegenerative disease: It has been shown that inflammation mediates NPA-induced brain degeneration, and activated microglia secreting cytokines interleukin-1α (IL-1α) and tumor necrosis factor α (TNFα) can induce a specific type of reactive neurotoxic astrocytes, named A1, which have been detected in post-mortem brain samples of Huntington’s, Alzheimer’s, and Parkinson’s diseases.