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 3

Amelioration of cognitive deficits observed in AAV-mediated CWG repeat–expressing mice by CWG-cPIP treatment.

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Amelioration of cognitive deficits observed in AAV-mediated CWG repeat–e...
(A) Schematic representation of viral constructs used in in vivo experiments and experimental schedules and representative confocal image of GFP expression in the hippocampus of CUG10 mice. Scale bar: 200 μm. (B and E) Spontaneous alternation behaviors and locomotor activities in the Y-maze test. *P < 0.05 and **P < 0.01, by 1-way ANOVA with Bonferroni’s multiple-comparison test. CUG10 plus vehicle and CUG300 plus vehicle: n = 11 mice; CUG300 plus CWG-cPIP: n = 9 mice each (B); n = 10 mice each (E). (C and F) Discrimination indices for the NOR test sessions. *P < 0.05 and **P < 0.01, by 1-way ANOVA with Bonferroni’s multiple-comparison test. CUG10 plus vehicle and CUG300 plus vehicle: n = 11 mice; CUG300 plus CWG-cPIP: n = 9 mice each (C); n = 10 mice each (F). (D and G) Latency to enter the dark compartment in the PA test sessions. *P < 0.05 and **P < 0.01, by 1-way ANOVA with Bonferroni’s multiple-comparison test. CUG10 plus vehicle and CUG300 plus vehicle: n = 11 mice; CUG300 plus CWG-cPIP: n = 9 mice each (D); n = 10 mice each (G). Data represent the mean ± SEM. Statistical data are provided in Supplemental Data File 6.