Methylmercury can induce Parkinson's-like neurotoxicity similar to 1-methyl-4- phenylpyridinium: a genomic and proteomic analysis on MN9D dopaminergic neuron cells

J Toxicol Sci. 2015 Dec;40(6):817-28. doi: 10.2131/jts.40.817.


Exposure to environmental chemicals has been implicated as a possible risk factor for the development of neurodegenerative diseases. Our previous study showed that methylmercury (MeHg) exposure can disrupt synthesis, uptake and metabolism of dopamine similar to 1-methyl-4-phenylpyridinium (MPP(+)). The objective of this study was to investigate the effects of MeHg exposure on gene and protein profiles in a dopaminergic MN9D cell line. MN9D cells were treated with MeHg (1-5 μM) and MPP(+) (10-40 μM) for 48 hr. Real-time PCR Parkinson's disease (PD) arrays and high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) were performed for the analysis. PD PCR array results showed that 19% genes were significantly changed in the 2.5 μM MeHg treated cells, and 39% genes were changed in the 5 μM MeHg treated cells. In comparison, MPP(+) treatment (40 µM) resulted in significant changes in 25% genes. A total of 15 common genes were altered by both MeHg and MPP(+), and dopaminergic signaling transduction was the most affected pathway. Proteomic analysis identified a total of 2496 proteins, of which 188, 233 and 395 proteins were differentially changed by 1 μM and 2.5 μM MeHg, and MPP(+) respectively. A total of 61 common proteins were changed by both MeHg and MPP(+) treatment. The changed proteins were mainly involved in energetic generation-related metabolism pathway (propanoate metabolism, pyruvate metabolism and fatty acid metabolism), oxidative phosphorylation, proteasome, PD and other neurodegenerative disorders. A total of 7 genes/proteins including Ube2l3 (Ubiquitin-conjugating enzyme E2 L3) and Th (Tyrosine 3-monooxygenase) were changed in both genomic and proteomic analysis. These results suggest that MeHg and MPP(+) share many similar signaling pathways leading to the pathogenesis of PD and other neurodegenerative diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1-Methyl-4-phenylpyridinium / toxicity*
  • Cells, Cultured
  • Dopamine / metabolism*
  • Dopamine / physiology
  • Dopaminergic Neurons / metabolism*
  • Energy Metabolism / genetics
  • Genome / drug effects*
  • Genomics*
  • Humans
  • Methylmercury Compounds / toxicity*
  • Neurotoxicity Syndromes / etiology*
  • Oxidative Phosphorylation
  • Parkinson Disease, Secondary / chemically induced*
  • Proteasome Endopeptidase Complex
  • Proteome / drug effects*
  • Proteomics*
  • Signal Transduction / drug effects
  • Tyrosine 3-Monooxygenase / metabolism
  • Ubiquitin-Conjugating Enzymes / metabolism


  • Methylmercury Compounds
  • Proteome
  • Tyrosine 3-Monooxygenase
  • Ubiquitin-Conjugating Enzymes
  • Proteasome Endopeptidase Complex
  • 1-Methyl-4-phenylpyridinium
  • Dopamine