Guo et al. observed that Nrf2 activity was reduced in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD, which enhances the PD phenotype and MPTP has been associated with iron deposit and astroglia HO-1 expression [37,46,47]. The gene discussed is HMOX1; the disease is Parkinson disease.