C3 and tauopathy: Neuroinflammation play an important role in patient with AD and other primary tauopathy diseases as well as in animal models of tauopathy (Heneka et al., 2015; Ising et al., 2019; Wu et al., 2019; Linnerbauer et al., 2020; Richetin et al., 2020; Gaikwad et al., 2021; McAlpine et al., 2021; Palleis et al., 2021), featured by disease associated with microglia activation, reactive astrocytes, and activated cytokines such as complement C3 and interleukin-3.