Inclusion body formation reduces levels of mutant huntingtin and the risk of neuronal death

Nature. 2004 Oct 14;431(7010):805-10. doi: 10.1038/nature02998.

Abstract

Huntington's disease is caused by an abnormal polyglutamine expansion within the protein huntingtin and is characterized by microscopic inclusion bodies of aggregated huntingtin and by the death of selected types of neuron. Whether inclusion bodies are pathogenic, incidental or a beneficial coping response is controversial. To resolve this issue we have developed an automated microscope that returns to precisely the same neuron after arbitrary intervals, even after cells have been removed from the microscope stage. Here we show, by survival analysis, that neurons die in a time-independent fashion but one that is dependent on mutant huntingtin dose and polyglutamine expansion; many neurons die without forming an inclusion body. Rather, the amount of diffuse intracellular huntingtin predicts whether and when inclusion body formation or death will occur. Surprisingly, inclusion body formation predicts improved survival and leads to decreased levels of mutant huntingtin elsewhere in a neuron. Thus, inclusion body formation can function as a coping response to toxic mutant huntingtin.

Publication types

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

MeSH terms

  • Animals
  • Cell Death
  • Cell Line
  • Cell Survival
  • Cells, Cultured
  • Humans
  • Huntingtin Protein
  • Huntington Disease / genetics
  • Huntington Disease / metabolism*
  • Huntington Disease / pathology*
  • Inclusion Bodies / metabolism*
  • Models, Biological
  • Mutation / genetics*
  • Neostriatum / cytology
  • Neostriatum / metabolism
  • Neostriatum / pathology
  • Nerve Tissue Proteins / chemistry
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism*
  • Neurons / cytology*
  • Neurons / metabolism*
  • Neurons / pathology
  • Nuclear Proteins / chemistry
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Peptides / chemistry
  • Peptides / genetics
  • Peptides / metabolism
  • Rats

Substances

  • HTT protein, human
  • Htt protein, rat
  • Huntingtin Protein
  • Nerve Tissue Proteins
  • Nuclear Proteins
  • Peptides
  • polyglutamine