CX3CR1 and neurodegenerative disease: CX3CR1 expression is reduced in “primed” microglia, thereby augmenting their responses to pro‐inflammatory stimuli (Niraula, Sheridan, & Godbout, 2017; Norden et al., 2015), with aging (Stojiljkovic et al., 2019) and in microglial phenotypes associated with neurodegenerative diseases (Deczkowska et al., 2018; Dubbelaar et al., 2018; Keren‐Shaul et al., 2017; Krasemann et al., 2017).