Regulation of α-synuclein expression in cultured cortical neurons

J Neurochem. 2011 Apr;117(2):275-85. doi: 10.1111/j.1471-4159.2011.07199.x. Epub 2011 Mar 1.

Abstract

Alpha-synuclein (SNCA) is a predominantly neuronal protein involved in the control of neurotransmitter release. The levels of SNCA expression are closely linked to the pathogenesis of Parkinson's disease; however, the biochemical pathways and transcriptional elements that control SNCA expression are not well understood. We previously used the model system of neurotrophin-mediated PC12 cell neuronal differentiation to examine these phenomena. Although these studies were informative, they were limited to the use of a cell line; therefore, in the current work, we have turned our attention to cultured primary rat cortical neurons. In these cultures, SNCA expression increased with time in culture, as the neurons mature. Luciferase assays based on transient transfections of fusion constructs encoding components of the transcriptional control region of SNCA identified various promoter areas that have a positive or negative effect on SNCA transcription. Intron 1, previously identified by us as an important regulatory region in the PC12 cell model, cooperates with regions 5' to exon 1 to mediate gene transcription. Using selective pharmacological tools, we find that tyrosine kinase receptors and the phosphatidyl-inositol 3 kinase signaling pathway are involved in mediating these effects. The exogenous application of the neurotrophin brain-derived neurotrophic factor (BDNF) is sufficient on its own to promote the transcriptional activation of SNCA through this pathway, but a neutralizing antibody against BDNF failed to affect SNCA transcription in maturing cultures, suggesting that BDNF is not the main factor involved in maturation-induced SNCA transcription in this model. Further in vivo studies are needed to establish the role of neurotrophin signaling in the control of SNCA transcription.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animals
  • Antibodies / pharmacology
  • Brain-Derived Neurotrophic Factor / immunology
  • Brain-Derived Neurotrophic Factor / pharmacology
  • Cells, Cultured
  • Cerebral Cortex / cytology*
  • Drug Administration Schedule
  • Drug Interactions
  • Embryo, Mammalian
  • Enzyme Inhibitors / pharmacology
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / physiology*
  • Neurons / drug effects
  • Neurons / metabolism*
  • Phosphatidylinositol 3-Kinases / metabolism
  • Promoter Regions, Genetic / drug effects
  • Promoter Regions, Genetic / genetics
  • Rats
  • Rats, Wistar
  • Signal Transduction / drug effects
  • Signal Transduction / physiology
  • Time Factors
  • Transfection / methods
  • alpha-Synuclein / genetics
  • alpha-Synuclein / metabolism*

Substances

  • Antibodies
  • Brain-Derived Neurotrophic Factor
  • Enzyme Inhibitors
  • alpha-Synuclein
  • Phosphatidylinositol 3-Kinases