CX3CR1 and amyotrophic lateral sclerosis: Exogenous CX3CL1 is neuroprotective in some other models of neuroinflammation [55, 56], and disruption of CX3CL1-CX3CR1 communication by deletion of the CX3CR1 gene causes neurotoxicity in mouse models of systemic inflammation, PD, and amyotrophic lateral sclerosis [57] but protects against neuronal loss in a mouse model of focal cerebral ischemia [58].