Then, in our in vivo studies of MPTP injury, we linked early SVZ impairment to WβC down‐regulation in PD mice and the early up‐regulation of microglial phagocyte oxidase (PHOX) and inducible‐nitric oxide synthase (iNOS), generating the highly toxic peroxynitrite fingerprint 3‐nitrotyrosine and defining the exacerbated, proinflammatory, microglial M1 phenotype. This evidence concerns the gene NOS2 and Parkinson disease.