Targeting CAG repeat RNAs reduces Huntington's disease phenotype independently of huntingtin levels

Laura Rué, Mónica Bañez-Corone, Jordi Creus-Muncunill, Albert Giralt, Rafael Alcalá-Vida, Gartze Mentxaka, Birgit Kagerbauer, M. Teresa Zomeño-Abellán, Zeus Aranda, Veronica Venturi, Esther Pérez-Navarro, Xavier P. Estivill, Eullia Martí

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Abstract

Huntington's disease (HD) is a polyglutamine disorder caused by a CAG expansion in the Huntingtin (HTT) gene exon 1. This expansion encodes a mutant protein whose abnormal function is traditionally associated with HD pathogenesis; however, recent evidence has also linked HD pathogenesis to RNA stable hairpins formed by the mutant HTT expansion. Here, we have shown that a locked nucleic acid-modified antisense oligonucleotide complementary to the CAG repeat (LNA-CTG) preferentially binds to mutant HTT without affecting HTT mRNA or protein levels. LNA-CTGs produced rapid and sustained improvement of motor deficits in an R6/2 mouse HD model that was paralleled by persistent binding of LNA-CTG to the expanded HTT exon 1 transgene. Motor improvement was accompanied by a pronounced recovery in the levels of several striatal neuronal markers severely impaired in R6/2 mice. Furthermore, in R6/2 mice, LNA-CTG blocked several pathogenic mechanisms caused by expanded CAG RNA, including small RNA toxicity and decreased Rn45s expression levels. These results suggest that LNA-CTGs promote neuroprotection by blocking the detrimental activity of CAG repeats within HTT mRNA. The present data emphasize the relevance of expanded CAG RNA to HD pathogenesis, indicate that inhibition of HTT expression is not required to reverse motor deficits, and further suggest a therapeutic potential for LNA-CTG in polyglutamine disorders.

Original languageEnglish
Pages (from-to)4319-4330
Number of pages12
JournalJournal of Clinical Investigation
Volume126
Issue number11
DOIs
Publication statusPublished - 1 Nov 2016
Externally publishedYes

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ASJC Scopus subject areas

  • Medicine(all)

Cite this

Rué, L., Bañez-Corone, M., Creus-Muncunill, J., Giralt, A., Alcalá-Vida, R., Mentxaka, G., Kagerbauer, B., Zomeño-Abellán, M. T., Aranda, Z., Venturi, V., Pérez-Navarro, E., Estivill, X. P., & Martí, E. (2016). Targeting CAG repeat RNAs reduces Huntington's disease phenotype independently of huntingtin levels. Journal of Clinical Investigation, 126(11), 4319-4330. https://doi.org/10.1172/JCI83185