The aim of these studies was to demonstrate the therapeutic capacity of an antisense oligonucleotide with the sequence (CUG)7 targeting the expanded CAG repeat in huntingtin (HTT) mRNA in vivo in the R6/2 N-terminal fragment and Q175 knock-in Huntington's disease (HD) mouse models. In a first study, R6/2 mice received six weekly intracerebroventricular infusions with a low and high dose of (CUG)7 and were sacrificed 2 weeks later. A 15-60% reduction of both soluble and aggregated mutant HTT protein was observed in striatum, hippocampus and cortex of (CUG)7-treated mice. This correction at the molecular level resulted in an improvement of performance in multiple motor tasks, increased whole brain and cortical volume, reduced levels of the gliosis marker myo-inositol, increased levels of the neuronal integrity marker N-aceyl aspartate and increased mRNA levels of the striatal marker Darpp-32. These neuroanatomical and neurochemical changes, together with the improved motor performance, suggest that treatment with (CUG)7 ameliorates basal ganglia dysfunction. The HTT-lowering was confirmed by an independent study in Q175 mice using a similar (CUG)7 AON dosing regimen, further demonstrating a lasting reduction of mutant HTT protein in striatum, hippocampus and cortex for up to 18 weeks post last infusion along with an increase in motor activity. Based on these encouraging results, (CUG)7 may thus offer an interesting alternative HTT-lowering strategy for HD.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5300196 | PMC |
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0171127 | PLOS |
Proc Natl Acad Sci U S A
January 2025
Program in Genetics, Molecular, and Cellular Biology, Tufts University Graduate School of Biomedical Sciences, Boston, MA 02111.
CAG/CTG repeats are prone to expansion, causing several inherited human diseases. The initiating sources of DNA damage which lead to inaccurate repair of the repeat tract to cause expansions are not fully understood. Expansion-prone CAG/CTG repeats are actively transcribed and prone to forming stable R-loops with hairpin structures forming on the displaced single-stranded DNA (S-loops).
View Article and Find Full Text PDFbioRxiv
December 2024
Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 600 North Wolfe Street, CMSC 5 South, Baltimore, MD21287.
Huntington's Disease (HD), a progressive neurodegenerative disorder with no disease-modifying therapies, is caused by a CAG repeat expansion in the HD gene encoding polyglutamine-expanded huntingtin (HTT) protein. Mechanisms of HD cellular pathogenesis and cellular functions of the normal and mutant HTT proteins are still not completely understood. HTT protein has numerous interaction partners, and it likely provides a scaffold for assembly of multiprotein complexes many of which may be altered in HD.
View Article and Find Full Text PDFNeurocase
January 2025
Department of Neurology, Dongguk University College of Medicine, Dongguk University Gyeongju Hospital, Gyeongju, Republic of Korea.
Dentatorubral-Pallidoluysian Atrophy (DRPLA) is a rare autosomal dominant neurodegenerative disorder caused by CAG repeat expansion in the ATN1 gene, characterized by diverse neurological and psychiatric symptoms. We report a 23-year-old patient with juvenile-onset seizures, cognitive decline, and ataxia, progressing to psychosis by age 31. Initial brain MRI showed minimal cerebellar atrophy, with prominent atrophy evident on follow-up imaging.
View Article and Find Full Text PDFEur J Neurol
January 2025
School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.
Background: The regulatory role of the apolipoprotein E (APOE) ε4 allele in the clinical manifestations of spinocerebellar ataxia type 3 (SCA3) remains unclear. This study aimed to evaluate the impact of the APOE ε4 allele on cognitive and motor functions in SCA3 patients.
Methods: This study included 281 unrelated SCA3 patients and 182 controls.
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