Iron transport in Parkinson's disease

Dopaminergic cell death in the substantia nigra (SN) is central to Parkinson's disease (PD) but the neurodegenerative mechanisms have not been completely elucidated. Iron accumulation in dopaminergic neurons and glial cells in the SN of PD patients may contribute to the generation of oxidative stress, protein aggregation and neuronal death. However, the mechanisms involved in iron accumulation remain unclear. In previous studies we excluded a role of transferrin and its receptor in iron accumulation while we showed that lactoferrin receptors were overexpressed in blood vessels and dopaminergic neurons in Parkinson's disease. We recently also described an increase in the expression of the divalent metal transporter 1 (DMT1/Nramp2/Slc11a2) in the SN of PD patients. Using the PD animal model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication in mice, we showed that DMT1 expression increased in the ventral mesencephalon of intoxicated animals, concomitant with iron accumulation, oxidative stress and dopaminergic cell loss. A mutation in DMT1 that impairs iron transport protected rodents against parkinsonism-inducing neurotoxins MPTP and 6-hydroxydopamine (6-OHDA). This study supports a critical role for DMT1 in iron-mediated neurodegeneration in PD.