However, whether CX3CL1-CX3CR1 pathway play a protective (Pabon et al., 2011; Morganti et al., 2012; Castro-Sanchez et al., 2018) or destructive (Shan et al., 2011; Thome et al., 2015) role in different PD animal models is still controversial (reviewed in Liu et al., 2019; Luo et al., 2019). This evidence concerns the gene CX3CR1 and Parkinson disease.