SNCA and Parkinson disease: Both pathologies are characterized by the accumulation in the brain of misfolded proteins [3, 4]: amyloid-beta (Aβ) in AD and alpha-synuclein (α-syn) in PD, as well as by neuroinflammation, which is driven both by microglial cells and by peripheral monocytes which cross the blood brain barrier (BBB) following a gradient of inflammatory cytokines [5].