Nuclear Localization of Huntingtin mRNA Is Specific to Cells of Neuronal Origin

  • Cell Rep. 2018 Sep 4;24(10):2553-2560.e5. doi: 10.1016/j.celrep.2018.07.106.
Marie-Cécile Didiot  1 ,  Chantal M Ferguson  2 ,  Socheata Ly  2 ,  Andrew H Coles  2 ,  Abigail O Smith  2 ,  Alicia A Bicknell  2 ,  Lauren M Hall  2 ,  Ellen Sapp  3 ,  Dimas Echeverria  2 ,  Athma A Pai  2 ,  Marian DiFiglia  3 ,  Melissa J Moore  2 ,  Lawrence J Hayward  4 ,  Neil Aronin  5 ,  Anastasia Khvorova  6
Affiliations
  • 1. RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA. Electronic address: [email protected].
  • 2. RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA.
  • 3. MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Charlestown, MA 02129, USA.
  • 4. Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
  • 5. RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA; Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
  • 6. RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA; Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA. Electronic address: [email protected].
PMID: 30184490 DOI: 10.1016/j.celrep.2018.07.106
Abstract

Huntington's disease (HD) is a monogenic neurodegenerative disorder representing an ideal candidate for gene silencing with oligonucleotide therapeutics (i.e., Antisense Oligonucleotides [ASOs] and small interfering RNAs [siRNAs]). Using an ultra-sensitive branched fluorescence in situ hybridization (FISH) method, we show that ∼50% of wild-type HTT mRNA localizes to the nucleus and that its nuclear localization is observed only in neuronal cells. In mouse brain sections, we detect Htt mRNA predominantly in neurons, with a wide range of Htt foci observed per cell. We further show that siRNAs and ASOs efficiently eliminate cytoplasmic HTT mRNA and HTT protein, but only ASOs induce a partial but significant reduction of nuclear HTT mRNA. We speculate that, like Other mRNAs, HTT mRNA subcellular localization might play a role in important neuronal regulatory mechanisms.

Keywords
ASOs; CAG repeat RNA foci; HTT mRNA; Huntington’s disease; RNA fluorescence in situ hybridization; confocal microscopy; siRNAs.
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