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Understanding the normal function of the Huntingtin (HTT) protein is of significance in the design and implementation of therapeutic strategies for Huntington's disease (HD). Expansion of the CAG repeat in the HTT gene, encoding an expanded polyglutamine (polyQ) repeat within the HTT protein, causes HD and may compromise HTT's normal activity contributing to HD pathology. Here, we investigated the previously defined role of HTT in autophagy specifically through studying HTT's association with ubiquitin. We find that HTT interacts directly with ubiquitin in vitro. Tandem affinity purification was used to identify ubiquitinated and ubiquitin-associated proteins that copurify with a HTT N-terminal fragment under basal conditions. Copurification is enhanced by HTT polyQ expansion and reduced by mimicking HTT serine 421 phosphorylation. The identified HTT-interacting proteins include RNA-binding proteins (RBPs) involved in mRNA translation, proteins enriched in stress granules, the nuclear proteome, the defective ribosomal products (DRiPs) proteome and the brain-derived autophagosomal proteome. To determine whether the proteins interacting with HTT are autophagic targets, HTT knockout (KO) cells and immunoprecipitation of lysosomes were used to investigate autophagy in the absence of HTT. HTT KO was associated with reduced abundance of mitochondrial proteins in the lysosome, indicating a potential compromise in basal mitophagy, and increased lysosomal abundance of RBPs which may result from compensatory up-regulation of starvation-induced macroautophagy. We suggest HTT is critical for appropriate basal clearance of mitochondrial proteins and RBPs, hence reduced HTT proteostatic function with mutation may contribute to the neuropathology of HD.

The field of Huntingtons disease research covers many different scientific disciplines, from molecular biology all the way through to clinical practice, and as our understanding of the disease has progressed over the decades, a great deal of different terminology has accrued. The field is also renowned for its collaborative spirit and use of standardized reagents, assays, datasets, models, and clinical measures, so the use of standardized terms is especially important. We have set out to determine, through a consensus exercise involving basic and clinical scientists working in the field, the most appropriate language to use across disciplines. Nominally, this article will serve as the style guide for the Journal of Huntingtons Disease (JHD), the only journal devoted exclusively to HD, and we lay out the preferred and standardized terminology and nomenclature for use in JHD publications. However, we hope that this article will also serve as a useful resource to the HD research community at large and that these recommended naming conventions will be adopted widely.

Background and Purpose Methods Results Conclusions Despite the wide use of dopamine receptor blocking agents (DRBAs) in Huntington disease (HD), neuroleptic malignant syndrome (NMS) is rarely described in this population. The aim of this study was to assess NMS prevalence in a large cohort of HD patients and explore the main associated risk factors.In 2023, an HD patient was admitted to our neurology department due to NMS. Starting from the case description, we performed a narrative review of the literature of NMS cases in HD, reviewed data from the fifth dataset of the Enroll‐HD (a longitudinal, observational, global study of families with HD) study (PDS5) selecting HD patients treated with DRBAs and/or tetrabenazine (TBZ) who presented at least one of the core symptoms of NMS (rigidity and hyperthermia), and collected data to investigate prevalence of NMS and identify risk factors.In the Enroll‐HD PDS5 dataset, we identified 5108 of 11,569 HD patients who were undergoing DRBA and/or TBZ treatment. Only one patient, a Caucasian man of 46 years, undergoing clozapine and valproate treatment, had a registered diagnosis of NMS.NMS in HD patients is seldom described. This could be due to an underestimation of this condition. There are no available objective NMS diagnostic criteria at present, and the existence of atypical forms of NMS further complicates diagnosis. Advanced disease stage, rigid–akinetic phenotype, abrupt therapy changes, polytherapy, and dehydration are key risk factors, most of which are preventable through awareness and caution in managing medications in the HD population. [ABSTRACT FROM AUTHOR]

Huntington's disease (HD) is an autosomal dominant neurodegenerative disease with a fatal outcome. There is accumulating evidence of a prominent role of glia in the pathology of HD, and we investigated this by conducting single nuclear RNA sequencing (snRNAseq) of human post mortem brain in four differentially affected regions; caudate nucleus, frontal cortex, hippocampus and cerebellum. Across 127,205 nuclei from donors with HD and age/sex matched controls, we found heterogeneity of glia which is altered in HD. We describe prominent changes in the abundance of certain subtypes of astrocytes, microglia, oligodendrocyte precursor cells and oligodendrocytes between HD and control samples, and these differences are widespread across brain regions. Furthermore, we highlight possible mechanisms that characterise the glial contribution to HD pathology including depletion of myelinating oligodendrocytes, an oligodendrocyte-specific upregulation of the calmodulin-dependent 3',5'-cyclic nucleotide phosphodiesterase 1 A (PDE1A) and an upregulation of molecular chaperones as a cross-glial signature and a potential adaptive response to the accumulation of mutant huntingtin (mHTT). Our results support the hypothesis that glia have an important role in the pathology of HD, and show that all types of glia are affected in the disease. [ABSTRACT FROM AUTHOR]