title: Up-regulation of divalent metal transporter 1 in 6-hydroxydopamine intoxication is IRE/IRP dependent.
abstract: Iron plays a key role in Parkinson's disease (PD). Increased iron content of the substantia nigra (SN) has been found in PD patients, and divalent metal transporter 1 (DMT1) has been shown to be up-regulated in the SN of both MPTP-induced PD models and PD patients. However, the mechanisms underlying DMT1 up-regulation are largely unknown. In the present study, we observed that in the SN of 6-hydroxydopamine (6-OHDA)-induced PD rats, DMT1 with the iron responsive element (IRE, DMT1+IRE), but not DMT1 without IRE (DMT1-IRE), was up-regulated, suggesting that increased DMT1+IRE expression might account for nigral iron accumulation in PD rats. This possibility was further assessed in an in vitro study using 6-OHDA-treated and DMT1+IRE-over-expressing MES23.5 cells. In 6-OHDA-treated MES23.5 cells, increased iron regulatory protein (IRP) 1 and IRP2 expression was observed, while silencing of IRPs dramatically diminished 6-OHDA-induced DMT1+IRE up-regulation. Pretreatment with N-acetyl-L-cysteine fully suppressed IRPs up-regulation by inhibition of 6-OHDA-induced oxidative stress. Increased DMT1+IRE expression resulted in increased iron influx by MES23.5 cells. Our data provide direct evidence that DMT1+IRE up-regulation can account for IRE/IRP-dependent 6-OHDA-induced iron accumulation initiated by 6-OHDA-induced intracellular oxidative stress and that increased levels of intracellular iron result in aggravated oxidative stress. The results of this study provide novel evidence supporting the use of anti-oxidants in the treatment of PD, with the goal of inhibiting iron accumulation by regulation of DMT1 expression.
authors.affiliation: Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao 266071, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Jiang
authors.forename: Ning
authors.initials: N
authors.lastname: Song
authors.forename: Huamin
authors.initials: H
authors.lastname: Xu
authors.forename: Shuzhen
authors.initials: S
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Junxia
authors.initials: J
authors.lastname: Xie
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D027682:Cation Transport Proteins / Q000378:metabolism*; D002460:Cell Line; D006892:Hydroxydopamines / Q000633:toxicity*; D007501:Iron / Q000378:metabolism; D035941:Iron Regulatory Protein 1 / Q000378:metabolism*; D035942:Iron Regulatory Protein 2 / Q000378:metabolism*; D018384:Oxidative Stress; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D020218:Response Elements; D015854:Up-Regulation; D000099236:Solute Carrier Family 11, Member 2
chemical_list: D000111:Acetylcysteine; D027682:Cation Transport Proteins; D006892:Hydroxydopamines; D007501:Iron; D035941:Iron Regulatory Protein 1; D035942:Iron Regulatory Protein 2; D017382:Reactive Oxygen Species; D000099236:Solute Carrier Family 11, Member 2