TNF and Parkinson disease: Also, transgenic animal models have confirmed the association between microglia and PD (Lachenmayer and Yue, 2012; Deng and Yuan, 2014), in which microglia were activated and TNF-α secretion was increased in the SN of mice overexpressing α-Syn, with subsequent neuronal death (Su et al., 2008; Sanchez-Guajardo et al., 2010).