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Brain region-specific degeneration and somatic expansions of the mutant Huntingtin (mHTT) CAG tract are key features of Huntington's disease (HD). However, the relationships among CAG expansions, death of specific cell types and molecular events associated with these processes are not established. Here, we used fluorescence-activated nuclear sorting (FANS) and deep molecular profiling to gain insight into the properties of cell types of the human striatum and cerebellum in HD and control donors. CAG expansions arise at mHTT in striatal medium spiny neurons (MSNs), cholinergic interneurons and cerebellar Purkinje neurons, and at mutant ATXN3 in MSNs from SCA3 donors. CAG expansions in MSNs are associated with higher levels of MSH2 and MSH3 (forming MutSβ), which can inhibit nucleolytic excision of CAG slip-outs by FAN1. Our data support a model in which CAG expansions are necessary but may not be sufficient for cell death and identify transcriptional changes associated with somatic CAG expansions and striatal toxicity.
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http://dx.doi.org/10.1038/s41588-024-01653-6 | DOI Listing |
Brain Commun
August 2025
Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA.
was identified in human and mouse Huntington's disease brain as the pathogenic exon 1 mRNA generated from aberrant splicing between exon 1 and 2 of that contributes to aggregate formation and neuronal dysfunction. Detection of the huntingtin exon 1 protein (HTT1a) has been accomplished with Meso Scale Discovery, Homogeneous Time Resolved Fluorescence and immunoprecipitation assays in Huntington's disease knock-in mice, but direct detection in homogenates by gel electrophoresis and western blot assay has been lacking. Subcellular fractions prepared from mouse and human Huntington's disease brain were separated by gel electrophoresis and probed by western blot with neoepitope monoclonal antibodies 1B12 and 11G2 directed to the C-terminal eight residues of HTT1a.
View Article and Find Full Text PDFNeurogenetics
September 2025
Nur International University, 54600, Lahore, Punjab, Pakistan.
Huntington's disease (HD) is a progressive, autosomal dominant neurodegenerative disorder characterized by motor dysfunction, cognitive decline, and psychiatric disturbances. It is caused by CAG repeat expansions in the HTT gene, resulting in the formation of mutant huntingtin protein that aggregates and disrupts neuronal function. This review outlines the pathogenesis of HD, including genetic, molecular, and environmental factors.
View Article and Find Full Text PDFNeurotherapeutics
September 2025
Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA. Electronic address:
Spinal and bulbar muscular atrophy (SBMA) is a CAG/polyglutamine (polyQ) repeat expansion disorder in which the mutant androgen receptor (AR) protein triggers progressive degeneration of the neuromuscular system in men. As the misfolded polyQ AR is the proximal mediator of toxicity, therapeutic efforts have focused on targeting the mutant protein, but these prior efforts have met with limited success in SBMA patients. Here, we examine the efficacy of small molecule AR proteolysis-targeting chimera (PROTAC) degraders that rapidly and potently promote AR ubiquitination and degradation by the proteasome.
View Article and Find Full Text PDFIn Silico Pharmacol
September 2025
School of Pharmacy, Swami Ramanand Teerth Marathwada University, Nanded, Maharashtra India.
Unlabelled: Huntington's disease (HD) is a progressive neurodegenerative disorder characterized by CAG repeat expansion in the HTT gene, leading to oxidative stress, mitochondrial dysfunction, and neuroinflammation. Conventional therapies offer only symptomatic relief with limited efficacy. This study aimed to explore the neuroprotective potential of (MP) and (BS) through an integrative bioinformatics approach, targeting multiple pathological mechanisms implicated in HD.
View Article and Find Full Text PDFBMC Neurol
September 2025
Department of Neurology, Asahi General Hospital, 1326 I, Asahi, Chiba 289-2511, Japan.
Background: Spinocerebellar ataxia type 8 (SCA8) is a rare neurodegenerative disease that is caused by CAG/CTG repeat expansion in the overlapping ATXN8 and ATXN8OS genes and basically entails slowly progressive cerebellar dysfunction with resultant dysarthria, limb incoordination, and gait instability. Moreover, patients with SCA8 may also exhibit pyramidal and extrapyramidal signs, cognitive decline, and involuntary movements. Although SCA8 is an autosomal dominant inheritance disorder, it sometimes seems to be sporadic because of reduced penetrance.
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