title: Metallothionein-mediated neuroprotection in genetically engineered mouse models of Parkinson's disease.
abstract: Parkinson's disease is characterized by a progressive loss of dopaminergic neurons in the substantia nigra zona compacta, and in other sub-cortical nuclei associated with a widespread occurrence of Lewy bodies. The cause of cell death in Parkinson's disease is still poorly understood, but a defect in mitochondrial oxidative phosphorylation and enhanced oxidative and nitrative stresses have been proposed. We have studied control(wt) (C57B1/6), metallothionein transgenic (MTtrans), metallothionein double gene knock (MTdko), alpha-synuclein knock out (alpha-syn(ko)), alpha-synuclein-metallothionein triple knock out (alpha-syn-MTtko), weaver mutant (wv/wv) mice, and Ames dwarf mice to examine the role of peroxynitrite in the etiopathogenesis of Parkinson's disease and aging. Although MTdko mice were genetically susceptible to 1, methyl, 4-phenyl, 1,2,3,6-tetrahydropyridine (MPTP) Parkinsonism, they did not exhibit any overt clinical symptoms of neurodegeneration and gross neuropathological changes as observed in wv/wv mice. Progressive neurodegenerative changes were associated with typical Parkinsonism in wv/wv mice. Neurodegenerative changes in wv/wv mice were observed primarily in the striatum, hippocampus and cerebellum. Various hallmarks of apoptosis including caspase-3, TNFalpha, NFkappaB, metallothioneins (MT-1, 2) and complex-1 nitration were increased; whereas glutathione, complex-1, ATP, and Ser(40)-phosphorylation of tyrosine hydroxylase, and striatal 18F-DOPA uptake were reduced in wv/wv mice as compared to other experimental genotypes. Striatal neurons of wv/wv mice exhibited age-dependent increase in dense cored intra-neuronal inclusions, cellular aggregation, proto-oncogenes (c-fos, c-jun, caspase-3, and GAPDH) induction, inter-nucleosomal DNA fragmentation, and neuro-apoptosis. MTtrans and alpha-Syn(ko) mice were genetically resistant to MPTP-Parkinsonism and Ames dwarf mice possessed significantly higher concentrations of striatal coenzyme Q10 and metallothioneins (MT 1, 2) and lived almost 2.5 times longer as compared to control(wt) mice. A potent peroxynitrite ion generator, 3-morpholinosydnonimine (SIN-1)-induced apoptosis was significantly attenuated in MTtrans fetal stem cells. These data are interpreted to suggest that peroxynitrite ions are involved in the etiopathogenesis of Parkinson's disease, and metallothionein-mediated coenzyme Q10 synthesis may provide neuroprotection.
authors.affiliation: Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota, 501 North Columbia Road, Grand Forks, ND 58203, USA. mebadi@medicine.nodak.edu
authors.forename: Manuchair
authors.initials: M
authors.lastname: Ebadi
authors.forename: Holly
authors.initials: H
authors.lastname: Brown-Borg
authors.forename: Hesham
authors.initials: H
authors.lastname: El Refaey
authors.forename: Brij B
authors.initials: BB
authors.lastname: Singh
authors.forename: Scott
authors.initials: S
authors.lastname: Garrett
authors.forename: Shaik
authors.initials: S
authors.lastname: Shavali
authors.forename: Sushil K
authors.initials: SK
authors.lastname: Sharma
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001921:Brain / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D003067:Coenzymes; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006801:Humans; D020267:MPTP Poisoning / Q000517:prevention & control; D008668:Metallothionein / Q000172:deficiency / Q000235:genetics* / Q000627:therapeutic use*; D051379:Mice; D008818:Mice, Neurologic Mutants / Q000502:physiology; D008822:Mice, Transgenic / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000172:deficiency / Q000235:genetics; D010300:Parkinson Disease / Q000209:etiology / Q000235:genetics* / Q000517:prevention & control*; D051843:Synucleins; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000378:metabolism; D051844:alpha-Synuclein
chemical_list: D003067:Coenzymes; D009419:Nerve Tissue Proteins; C497604:SNCA protein, human; C497605:Snca protein, mouse; D051843:Synucleins; D051844:alpha-Synuclein; D014451:Ubiquinone; D008668:Metallothionein; C024989:coenzyme Q10; D004298:Dopamine