SNCA and Parkinson disease: Microglia and astrocyte could be activated by multiple factors related to PD, such as the pivotal PD-associated genes [α-synuclein (SNCA), Parkin, deglycase (DJ-1), leucine-rich repeat kinase 2 (LRRK2)] and neurotoxins (rotenone and methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Wang et al., 2015).