CX3CL1 and Alzheimer disease: Studies on animal models of Tau pathology and Aβ pathology have documented a role of CX3CL1/CX3CR1 signalling in the pathogenesis of AD, but controversial results have been achieved, with the FKN pathway being neurotoxic or neuroprotective depending on the mouse model used [64,65,66,67,68,69].