Allele-selective transcriptional repression of mutant HTT for the treatment of Huntington's disease

Nat Med. 2019 Jul;25(7):1131-1142. doi: 10.1038/s41591-019-0478-3. Epub 2019 Jul 1.

Abstract

Huntington's disease (HD) is a dominantly inherited neurodegenerative disorder caused by a CAG trinucleotide expansion in the huntingtin gene (HTT), which codes for the pathologic mutant HTT (mHTT) protein. Since normal HTT is thought to be important for brain function, we engineered zinc finger protein transcription factors (ZFP-TFs) to target the pathogenic CAG repeat and selectively lower mHTT as a therapeutic strategy. Using patient-derived fibroblasts and neurons, we demonstrate that ZFP-TFs selectively repress >99% of HD-causing alleles over a wide dose range while preserving expression of >86% of normal alleles. Other CAG-containing genes are minimally affected, and virally delivered ZFP-TFs are active and well tolerated in HD neurons beyond 100 days in culture and for at least nine months in the mouse brain. Using three HD mouse models, we demonstrate improvements in a range of molecular, histopathological, electrophysiological and functional endpoints. Our findings support the continued development of an allele-selective ZFP-TF for the treatment of HD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles*
  • Animals
  • Cells, Cultured
  • Disease Models, Animal
  • Female
  • Humans
  • Huntingtin Protein / genetics*
  • Huntington Disease / genetics
  • Huntington Disease / therapy*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Inbred CBA
  • Mutation*
  • Neuroprotection
  • Transcription, Genetic*
  • Trinucleotide Repeats
  • Zinc Fingers*

Substances

  • HTT protein, human
  • Huntingtin Protein