Metallothionein attenuates 3-morpholinosydnonimine (SIN-1)-induced oxidative stress in dopaminergic neurons

Antioxid Redox Signal. 2003 Jun;5(3):251-64. doi: 10.1089/152308603322110832.


Parkinson's disease is characterized by a progressive loss of dopaminergic neurons in the substantia nigra zona compacta, and in other subcortical nuclei associated with a widespread occurrence of Lewy bodies. The causes of cell death in Parkinson's disease are still poorly understood, but a defect in mitochondrial oxidative phosphorylation and enhanced oxidative stress have been proposed. We have examined 3-morpholinosydnonimine (SIN-1)-induced apoptosis in control and metallothionein-overexpressing dopaminergic neurons, with a primary objective to determine the neuroprotective potential of metallothionein against peroxynitrite-induced neurodegeneration in Parkinson's disease. SIN-1 induced lipid peroxidation and triggered plasma membrane blebbing. In addition, it caused DNA fragmentation, alpha-synuclein induction, and intramitochondrial accumulation of metal ions (copper, iron, zinc, and calcium), and enhanced the synthesis of 8-hydroxy-2-deoxyguanosine. Furthermore, it down-regulated the expression of Bcl-2 and poly(ADP-ribose) polymerase, but up-regulated the expression of caspase-3 and Bax in dopaminergic (SK-N-SH) neurons. SIN-1 induced apoptosis in aging mitochondrial genome knockout cells, alpha-synuclein-transfected cells, metallothionein double-knockout cells, and caspase-3-overexpressed dopaminergic neurons. SIN-1-induced changes were attenuated with selegiline or in metallothionein-transgenic striatal fetal stem cells. SIN-1-induced oxidation of dopamine to dihydroxyphenylacetaldehyde was attenuated in metallothionein-transgenic fetal stem cells and in cells transfected with a mitochondrial genome, and enhanced in aging mitochondrial genome knockout cells, in metallothionein double-knockout cells and caspase-3 gene-overexpressing dopaminergic neurons. Selegiline, melatonin, ubiquinone, and metallothionein suppressed SIN-1-induced down-regulation of a mitochondrial genome and up-regulation of caspase-3 as determined by reverse transcription-polymerase chain reaction. The synthesis of mitochondrial 8-hydroxy-2-deoxyguanosine and apoptosis-inducing factors were increased following exposure to 1-methyl-4-phenylpyridinium ion or rotenone. Pretreatment with selegiline or metallothionein suppressed 1-methyl-4-phenylpyridinium ion-, 6-hydroxydopamine-, and rotenone-induced increases in mitochondrial 8-hydroxy-2-deoxyguanosine accumulation. Transfection of aging mitochondrial genome knockout neurons with mitochondrial genome encoding complex-1 or melanin attenuated the SIN-1-induced increase in lipid peroxidation. SIN-1 induced the expression of alpha-synuclein, caspase-3, and 8-hydroxy-2-deoxyguanosine, and augmented protein nitration. These effects were attenuated by metallothionein gene overexpression. These studies provide evidence that nitric oxide synthase activation and peroxynitrite ion overproduction may be involved in the etiopathogenesis of Parkinson's disease, and that metallothionein gene induction may provide neuroprotection.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Apoptosis / physiology
  • Caspase 3
  • Caspases / metabolism
  • Cell Line, Tumor
  • Corpus Striatum / cytology
  • Corpus Striatum / drug effects
  • Corpus Striatum / embryology
  • Deoxyadenosines / biosynthesis
  • Dopamine / metabolism
  • Gene Expression Regulation / drug effects
  • Humans
  • Lipid Peroxidation / drug effects
  • Lipid Peroxidation / physiology
  • Metallothionein / genetics
  • Metallothionein / metabolism
  • Metallothionein / pharmacology
  • Metallothionein / physiology*
  • Metals / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • Molsidomine / analogs & derivatives*
  • Molsidomine / antagonists & inhibitors*
  • Molsidomine / toxicity
  • Nerve Tissue Proteins / biosynthesis
  • Neurons / drug effects*
  • Neurons / metabolism*
  • Neuroprotective Agents / metabolism
  • Neuroprotective Agents / pharmacology
  • Oxidative Stress / drug effects
  • Oxidative Stress / physiology
  • Selegiline / pharmacology
  • Stem Cells / drug effects
  • Stem Cells / metabolism
  • Stem Cells / ultrastructure
  • Synucleins
  • Transcriptional Activation
  • alpha-Synuclein


  • 8-hydroxy-2'-deoxyadenosine
  • Deoxyadenosines
  • Metals
  • Nerve Tissue Proteins
  • Neuroprotective Agents
  • SNCA protein, human
  • Snca protein, mouse
  • Synucleins
  • alpha-Synuclein
  • Selegiline
  • linsidomine
  • Metallothionein
  • Molsidomine
  • CASP3 protein, human
  • Casp3 protein, mouse
  • Caspase 3
  • Caspases
  • Dopamine