A cyclic pyrrole-imidazole polyamide reduces pathogenic RNA in CAG/CTG triplet repeat neurological disease models
Susumu Ikenoshita, … , Hiroshi Sugiyama, Norifumi Shioda
Susumu Ikenoshita, … , Hiroshi Sugiyama, Norifumi Shioda
Published September 14, 2023
Citation Information: J Clin Invest. 2023;133(22):e164792. https://doi.org/10.1172/JCI164792.
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Research Article Neuroscience

A cyclic pyrrole-imidazole polyamide reduces pathogenic RNA in CAG/CTG triplet repeat neurological disease models

Abstract

Expansion of CAG and CTG (CWG) triplet repeats causes several inherited neurological diseases. The CWG repeat diseases are thought to involve complex pathogenic mechanisms through expanded CWG repeat–derived RNAs in a noncoding region and polypeptides in a coding region, respectively. However, an effective therapeutic approach has not been established for the CWG repeat diseases. Here, we show that a CWG repeat DNA–targeting compound, cyclic pyrrole–imidazole polyamide (CWG-cPIP), suppressed the pathogenesis of coding and noncoding CWG repeat diseases. CWG-cPIP bound to the hairpin form of mismatched CWG DNA, interfering with transcription elongation by RNA polymerase through a preferential activity toward repeat-expanded DNA. We found that CWG-cPIP selectively inhibited pathogenic mRNA transcripts from expanded CWG repeats, reducing CUG RNA foci and polyglutamine accumulation in cells from patients with myotonic dystrophy type 1 (DM1) and Huntington’s disease (HD). Treatment with CWG-cPIP ameliorated behavioral deficits in adeno-associated virus–mediated CWG repeat–expressing mice and in a genetic mouse model of HD, without cytotoxicity or off-target effects. Together, we present a candidate compound that targets expanded CWG repeat DNA independently of its genomic location and reduces both pathogenic RNA and protein levels. CWG-cPIP may be used for the treatment of CWG repeat diseases and improvement of clinical outcomes.

Authors

Susumu Ikenoshita, Kazuya Matsuo, Yasushi Yabuki, Kosuke Kawakubo, Sefan Asamitsu, Karin Hori, Shingo Usuki, Yuki Hirose, Toshikazu Bando, Kimi Araki, Mitsuharu Ueda, Hiroshi Sugiyama, Norifumi Shioda

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Figure 5

Inhibition of nuclear CUG RNA foci seen in CUG300 mice by CWG-cPIP treatment.

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Inhibition of nuclear CUG RNA foci seen in CUG300 mice by CWG-cPIP treat...
(A) Representative confocal images of Nissl-stained sections. Scale bars: 1 mm (left) and 500 μm (right). (B) Representative confocal images of CUG-RNA (magenta), GFP (green), and NeuN (red) in the hippocampus and quantification of NeuN-positive cells in CA1 and DG regions. *P < 0.05 and **P < 0.01, by 1-way ANOVA with Bonferroni’s multiple-comparison test. n = 4 mice each, averaged from 3 independent replicates (n = 3 slices) per mouse. Scale bars: 200 μm. (C) Representative confocal images of CUG-RNA foci in the hippocampal CA1 and DG regions and their quantification. *P < 0.05 and **P < 0.01, by 2-sided, unpaired Student’s t test. n = 4 mice each, averaged from 3 independent replicates (n = 3 slices) per mouse. Scale bars: 5 μm. Data represent the mean ± SEM. Statistical data are provided in Supplemental Data File 6.