Transcriptional dysregulation of coding and non-coding genes in cellular models of Huntington's disease

Biochem Soc Trans. 2009 Dec;37(Pt 6):1270-5. doi: 10.1042/BST0371270.

Abstract

HD (Huntington's disease) is a late onset heritable neurodegenerative disorder that is characterized by neuronal dysfunction and death, particularly in the cerebral cortex and medium spiny neurons of the striatum. This is followed by progressive chorea, dementia and emotional dysfunction, eventually resulting in death. HD is caused by an expanded CAG repeat in the first exon of the HD gene that results in an abnormally elongated polyQ (polyglutamine) tract in its protein product, Htt (Huntingtin). Wild-type Htt is largely cytoplasmic; however, in HD, proteolytic N-terminal fragments of Htt form insoluble deposits in both the cytoplasm and nucleus, provoking the idea that mutHtt (mutant Htt) causes transcriptional dysfunction. While a number of specific transcription factors and co-factors have been proposed as mediators of mutHtt toxicity, the causal relationship between these Htt/transcription factor interactions and HD pathology remains unknown. Previous work has highlighted REST [RE1 (repressor element 1)-silencing transcription factor] as one such transcription factor. REST is a master regulator of neuronal genes, repressing their expression. Many of its direct target genes are known or suspected to have a role in HD pathogenesis, including BDNF (brain-derived neurotrophic factor). Recent evidence has also shown that REST regulates transcription of regulatory miRNAs (microRNAs), many of which are known to regulate neuronal gene expression and are dysregulated in HD. Thus repression of miRNAs constitutes a second, indirect mechanism by which REST can alter the neuronal transcriptome in HD. We will describe the evidence that disruption to the REST regulon brought about by a loss of interaction between REST and mutHtt may be a key contributory factor in the widespread dysregulation of gene expression in HD.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Brain-Derived Neurotrophic Factor / genetics
  • Brain-Derived Neurotrophic Factor / metabolism
  • Gene Expression Regulation*
  • Humans
  • Huntingtin Protein
  • Huntington Disease / genetics*
  • MicroRNAs / genetics
  • MicroRNAs / metabolism
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Neurons* / cytology
  • Neurons* / physiology
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism
  • Transcription, Genetic*

Substances

  • Brain-Derived Neurotrophic Factor
  • HTT protein, human
  • Huntingtin Protein
  • MicroRNAs
  • Nerve Tissue Proteins
  • Nuclear Proteins
  • RE1-silencing transcription factor
  • Repressor Proteins