Tandem repeat diseases include the neurodegenerative disorders known as polyglutamine (polyQ) diseases, caused by CAG repeat expansions in the coding regions of the respective disease genes. The nine known polyQ disease include Huntington's disease (HD), dentatorubral-pallidoluysian atrophy (DRPLA), spinal bulbar muscular atrophy (SBMA), and six spinocerebellar ataxias (SCA1, SCA2, SCA3, SCA6, SCA7, and SCA17). The underlying disease mechanism in the polyQ diseases is thought principally to reflect dominant toxic properties of the disease proteins which, when harboring a polyQ expansion, differentially interact with protein partners and are prone to aggregate. Among the polyQ diseases, SCA3 is the most common SCA, and second to HD in prevalence worldwide. Here we summarize current understanding of SCA3 disease mechanisms within the broader context of the broader polyQ disease field. We emphasize properties of the disease protein, ATXN3, and new discoveries regarding three potential pathogenic mechanisms: 1) altered protein homeostasis; 2) DNA damage and dysfunctional DNA repair; and 3) nonneuronal contributions to disease. We conclude with an overview of the therapeutic implications of recent mechanistic insights.
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http://dx.doi.org/10.1016/j.nbd.2019.104635 | DOI Listing |
Methods Cell Biol
January 2025
State University of Minas Gerais, Department of Biomedical Sciences and Health, Passos, MG, Brazil. Electronic address:
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterized by a repeat of the cytosine-adenine-guanine trinucleotide (CAG) in the huntingtin gene (HTT). This results in the translation of a mutant huntingtin (mHTT) protein with an abnormally long polyglutamine (polyQ) repeat. The pathology of HD leads to neuronal cell loss, motor abnormalities, and dementia.
View Article and Find Full Text PDFFront Mol Biosci
January 2025
Center for Biomolecular and Cellular Structure, Institute for Basic Science, Daejeon, Republic of Korea.
Huntington's disease (HD) is primarily caused by the aberrant aggregation of the N-terminal exon 1 fragment of mutant huntingtin protein (mHttex1) with expanded polyglutamine (polyQ) repeats in neurons. The first 17 amino acids of the N-terminus of Httex1 (N17 domain) immediately preceding the polyQ repeat domain are evolutionarily conserved across vertebrates and play multifaceted roles in the pathogenesis of HD. Due to its amphipathic helical properties, the N17 domain, both alone and when membrane-associated, promotes mHttEx1 aggregation.
View Article and Find Full Text PDFFree Neuropathol
January 2024
Department of Pathology, Nash Family Department of Neuroscience, Department of Artificial Intelligence & Human Health, Neuropathology Brain Bank & Research CoRE, Ronald M. Loeb Center for Alzheimer's Disease, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
This review highlights a collection of both diverse and highly impactful studies published in the previous year selected by the author from the neurodegenerative neuropathology literature. As with previous reviews in this series, the focus is, to the best of my ability, to highlight human tissue-based experimentation most relevant to experimental and clinical neuropathologists. A concerted effort was made to balance the selected studies across neurodegenerative disease categories, approaches, and methodologies to capture the breadth of the research landscape.
View Article and Find Full Text PDFNeurogenetics
January 2025
Neuropharmacology Division, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, 142001, India.
Huntington's disease (HDs) is a fatal, autosomal dominant, and hereditary neurodegenerative disorder characterized by progressive motor dysfunction, cognitive decline, and psychiatric disturbances. HD is well linked to mutation in the HTT gene, which leads to an abnormal expansion of trinucleotide CAG repeats, resulting in the production of the mHTT protein and responsible for abnormally long poly-Q tract. These abnormal proteins disrupt cellular processes, including neuroinflammation, endoplasmic reticulum (ER) stress, and mitochondrial dysfunction, ultimately leading to selective neuronal loss in the brain.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Department of Biomaterials & Biomedical Technology (BBT), University Medical Centre Groningen (UMCG), Antonius Deusinglaan 1, Groningen, 9713 AV, The Netherlands.
Free radicals are believed to play a secondary role in the cell death cascade associated with various diseases. In Huntington's disease (HD), the aggregation of polyglutamine (PolyQ) not only contributes to the disease but also elevates free radical levels. However, measuring free radicals is difficult due to their short lifespan and limited diffusion range.
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