CX3CL1 and Parkinson disease: Exogenous CX3CL1 is neuro-protective in some models of neuro-inflammation [94,95], and disruption of CX3CL1 signaling causes neurotoxicity in models of systemic inflammation, PD, and amyotrophic lateral sclerosis [96] but protects against neuronal loss in a mouse model of focal cerebral ischemia [97].