Targeting several CAG expansion diseases by a single antisense oligonucleotide.

Joseph Charles Glorioso,Melvin M Evers,Barry A Pepers,Willeke M C Van Roon-Mom,Annemieke Aartsma-Rus,Judith C T Van Deutekom,Johan T Den Dunnen,Susan A M Mulders,Gert-Jan B Van Ommen

doi:10.1371/journal.pone.0024308

Joseph Charles Glorioso, Melvin M Evers + Show 7 more

Open Access

https://doi.org/10.1371/journal.pone.0024308

Copy DOI

Abstract

To date there are 9 known diseases caused by an expanded polyglutamine repeat, with the most prevalent being Huntington's disease. Huntington's disease is a progressive autosomal dominant neurodegenerative disorder for which currently no therapy is available. It is caused by a CAG repeat expansion in the HTT gene, which results in an expansion of a glutamine stretch at the N-terminal end of the huntingtin protein. This polyglutamine expansion plays a central role in the disease and results in the accumulation of cytoplasmic and nuclear aggregates. Here, we make use of modified 2′-O-methyl phosphorothioate (CUG)n triplet-repeat antisense oligonucleotides to effectively reduce mutant huntingtin transcript and protein levels in patient-derived Huntington's disease fibroblasts and lymphoblasts. The most effective antisense oligonucleotide, (CUG)7, also reduced mutant ataxin-1 and ataxin-3 mRNA levels in spinocerebellar ataxia 1 and 3, respectively, and atrophin-1 in dentatorubral-pallidoluysian atrophy patient derived fibroblasts. This antisense oligonucleotide is not only a promising therapeutic tool to reduce mutant huntingtin levels in Huntington's disease but our results in spinocerebellar ataxia and dentatorubral-pallidoluysian atrophy cells suggest that this could also be applicable to other polyglutamine expansion disorders as well.

Highlights

Polyglutamine diseases are a group of disorders caused by CAG triplet repeat expansions in the coding region of the genome
We examine the effect of (CUG)n antisense oligonucleotides (AONs) on mRNA level in cell lines derived from Huntington’s disease (HD), SCA1, SCA3, and dentatorubral-pallidoluysian atrophy (DRPLA) patients with CAG expansions that occur most frequently in the patient population
Patient-derived human fibroblasts were transfected with AONs with 3, 7 and 12 consecutive CUGs ((CUG)3, (CUG)7, and (CUG)12, respectively) and total RNA was isolated after 48 hours

Summary

Introduction

Polyglutamine (polyQ) diseases are a group of disorders caused by CAG triplet repeat expansions in the coding region of the genome. Total loss of the endogenous htt homolog in a Drosophila HD model expressing the human first exon of the HTT gene with 93 Qs enhanced the HD pathogenesis [29] These studies show that a specific reduction of mutant htt levels, leaving as much wild type htt protein as possible, would be the optimal outcome of a therapy aimed at htt knockdown. Off-target effects and interference with endogenous RNAi processes remains to be assessed [32], these results are encouraging Another RNA based therapy approach to knock down gene or protein expression is the use of single stranded antisense oligonucleotides (AONs). Lowering the AON concentration increased the specificity for the mutant transcript These results show that one single antisense oligonucleotide could be a promising therapeutic treatment for all polyQ disorders

Results

Discussion

Findings

Materials and Methods