scholarly journals Lack of RAN-mediated toxicity in Huntington’s disease knock-in mice

2020 ◽  
Vol 117 (8) ◽  
pp. 4411-4417 ◽  
Author(s):  
Su Yang ◽  
Huiming Yang ◽  
Luoxiu Huang ◽  
Luxiao Chen ◽  
Zhaohui Qin ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Genome Editing ◽  
Mouse Models ◽  
Cag Repeat ◽  
Cag Repeats ◽  
Behavioral Phenotypes ◽  
Endogenous Level ◽  
Ran Translation

Identification of repeat-associated non-AUG (RAN) translation in trinucleotide (CAG) repeat diseases has led to the emerging concept that CAG repeat diseases are caused by nonpolyglutamine products. Nonetheless, the in vivo contribution of RAN translation to the pathogenesis of CAG repeat diseases remains elusive. Via CRISPR/Cas9-mediated genome editing, we established knock-in mouse models that harbor expanded CAG repeats in the mouse huntingtin gene to express RAN-translated products with or without polyglutamine peptides. We found that RAN translation is not detected in the knock-in mouse models when expanded CAG repeats are expressed at the endogenous level. Consistently, the expanded CAG repeats that cannot be translated into polyglutamine repeats do not yield the neuropathological and behavioral phenotypes that were found in knock-in mice expressing expanded polyglutamine repeats. Our findings suggest that RAN-translated products do not play a major role in the pathogenesis of CAG repeat diseases and underscore the importance in targeting polyglutamine repeats for therapeutics.

scholarly journals Defective linear and circular RNAs biogenesis in Huntington's disease: CAG repeat expansion hijacks neuronal splicing

2021 ◽  
Author(s):  
Dilara Ayyildiz ◽  
Alan Monziani ◽  
Takshashila Tripathi ◽  
Jessica Doering ◽  
Guendalina Bergonzoni ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Rna Binding ◽  
Neural Progenitors ◽  
Cag Repeat ◽  
Cag Repeats ◽  
Circular Rnas ◽  
In Vivo Models ◽  
Micro Rnas

Alternative splicing (AS) appears to be altered in Huntington's disease (HD), but its significance for early, pre-symptomatic disease stages has not been inspected. Here, taking advantage of Htt CAG knock-in mouse in vitro and in vivo models, we demonstrate a strong correlation between Htt CAG repeat length and increased aberrant linear AS, specifically affecting neural progenitors and, in vivo, the striatum prior to overt behavioral phenotypes stages. Remarkably, expanded Htt CAG repeats reflect on a previously neglected, global impairment of back-splicing, leading to decreased circular RNAs production in neural progenitors. Though the mechanisms of this dysregulation remain uncertain, our study unveils network of transcriptionally altered micro-RNAs and RNA-binding proteins (CELF, hnRNPS, PTBP, SRSF) which, in turn, might influence the AS machinery, primarily in neural cells. We suggest that this unbalanced expression of linear and circular RNAs might result in altered neural fitness, contributing to HD striatal vulnerability.

scholarly journals Skeletal muscle regeneration is altered in the R6/2 mouse model of Huntington's disease

2022 ◽  
Author(s):  
Sanzana Hoque ◽  
Marie Sjogren ◽  
Valerie Allamand ◽  
Kinga Gawlik ◽  
Naomi Franke ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Muscle Damage ◽  
Satellite Cell ◽  
Mouse Models ◽  
Satellite Cells ◽  
Muscle Fibers ◽  
Cag Repeat ◽  
Skeletal Muscle Regeneration

Huntington's disease (HD) is caused by CAG repeat expansion in the huntingtin (HTT) gene. Skeletal muscle wasting alongside central pathology is a well-recognized phenomenon seen in patients with HD and HD mouse models. HD muscle atrophy progresses with disease and affects prognosis and quality of life. Satellite cells, progenitors of mature skeletal muscle fibers, are essential for proliferation, differentiation, and repair of muscle tissue in response to muscle injury or exercise. In this study, we aim to investigate the effect of mutant HTT on the differentiation and regeneration capacity of HD muscle by employing in vitro mononuclear skeletal muscle cell isolation and in vivo acute muscle damage model in R6/2 mice. We found that, similar to R6/2 adult mice, neonatal R6/2 mice also exhibit a significant reduction in myofiber width and morphological changes in gastrocnemius and soleus muscles compared to WT mice. Cardiotoxin (CTX)-induced acute muscle damage in R6/2 and WT mice showed that the Pax7+ satellite cell pool was dampened in R6/2 mice at 4 weeks post-injection, and R6/2 mice exhibited an altered inflammatory profile in response to acute damage. Our results suggest that, in addition to the mutant HTT degenerative effects in mature muscle fibers, expression of mutant HTT in satellite cells might alter developmental and regenerative processes to contribute to the progressive muscle mass loss in HD. Taken together, the results presented here encourage further studies evaluating the underlying mechanisms of satellite cell dysfunction in HD mouse models.

scholarly journals Juvenile Huntington’s Disease and Other PolyQ Diseases, Update on Neurodevelopmental Character and Comparative Bioinformatic Review of Transcriptomic and Proteomic Data

2021 ◽  
Vol 9 ◽  
Author(s):  
Karolina Świtońska-Kurkowska ◽  
Bart Krist ◽  
Joanna Delimata ◽  
Maciej Figiel
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Mouse Models ◽  
Muscular Atrophy ◽  
Expression Patterns ◽  
Cag Repeat ◽  
Human Cognition ◽  
Expression Data ◽  
Neuronal Stem Cell ◽  
Polyq Diseases

Polyglutamine (PolyQ) diseases are neurodegenerative disorders caused by the CAG repeat expansion mutation in affected genes resulting in toxic proteins containing a long chain of glutamines. There are nine PolyQ diseases: Huntington’s disease (HD), spinocerebellar ataxias (types 1, 2, 3, 6, 7, and 17), dentatorubral-pallidoluysian atrophy (DRPLA), and spinal bulbar muscular atrophy (SBMA). In general, longer CAG expansions and longer glutamine tracts lead to earlier disease presentations in PolyQ patients. Rarely, cases of extremely long expansions are identified for PolyQ diseases, and they consistently lead to juvenile or sometimes very severe infantile-onset polyQ syndromes. In apparent contrast to the very long CAG tracts, shorter CAGs and PolyQs in proteins seems to be the evolutionary factor enhancing human cognition. Therefore, polyQ tracts in proteins can be modifiers of brain development and disease drivers, which contribute neurodevelopmental phenotypes in juvenile- and adult-onset PolyQ diseases. Therefore we performed a bioinformatics review of published RNAseq polyQ expression data resulting from the presence of polyQ genes in search of neurodevelopmental expression patterns and comparison between diseases. The expression data were collected from cell types reflecting stages of development such as iPSC, neuronal stem cell, neurons, but also the adult patients and models for PolyQ disease. In addition, we extended our bioinformatic transcriptomic analysis by proteomics data. We identified a group of 13 commonly downregulated genes and proteins in HD mouse models. Our comparative bioinformatic review highlighted several (neuro)developmental pathways and genes identified within PolyQ diseases and mouse models responsible for neural growth, synaptogenesis, and synaptic plasticity.

scholarly journals The MID1 Protein: A Promising Therapeutic Target in Huntington’s Disease

2021 ◽  
Vol 12 ◽  
Author(s):  
Annika Heinz ◽  
Judith Schilling ◽  
Willeke van Roon-Mom ◽  
Sybille Krauß
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Protein A ◽  
Cag Repeat ◽  
Cag Repeats ◽  
Progressive Movement ◽  
Promising Therapeutic Target ◽  
Promising Therapeutic Approach ◽  
Exon 1 ◽  
Polyglutamine Protein

Huntington’s disease (HD) is caused by an expansion mutation of a CAG repeat in exon 1 of the huntingtin (HTT) gene, that encodes an expanded polyglutamine tract in the HTT protein. HD is characterized by progressive psychiatric and cognitive symptoms associated with a progressive movement disorder. HTT is ubiquitously expressed, but the pathological changes caused by the mutation are most prominent in the central nervous system. Since the mutation was discovered, research has mainly focused on the mutant HTT protein. But what if the polyglutamine protein is not the only cause of the neurotoxicity? Recent studies show that the mutant RNA transcript is also involved in cellular dysfunction. Here we discuss the abnormal interaction of the mutant HTT transcript with a protein complex containing the MID1 protein. MID1 aberrantly binds to CAG repeats and this binding increases with CAG repeat length. Since MID1 is a translation regulator, association of the MID1 complex stimulates translation of mutant HTT mRNA, resulting in an overproduction of polyglutamine protein. Thus, blocking the interaction between MID1 and mutant HTT mRNA is a promising therapeutic approach. Additionally, we show that MID1 expression in the brain of both HD patients and HD mice is aberrantly increased. This finding further supports the concept of blocking the interaction between MID1 and mutant HTT mRNA to counteract mutant HTT translation as a valuable therapeutic strategy. In line, recent studies in which either compounds affecting the assembly of the MID1 complex or molecules targeting HTT RNA, show promising results.

scholarly journals The longevity-associated variant of BPIFB4 improves a CXCR4-mediated striatum–microglia crosstalk preventing disease progression in a mouse model of Huntington’s disease

2020 ◽  
Vol 11 (7) ◽  
Author(s):  
Alba Di Pardo ◽  
Elena Ciaglia ◽  
Monica Cattaneo ◽  
Anna Maciag ◽  
Francesco Montella ◽  
...  
Keyword(s):  
Mouse Model ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Neurodegenerative Disorder ◽  
Motor Dysfunction ◽  
Cag Repeats ◽  
Huntingtin Protein ◽  
Human Microglia

Abstract The longevity-associated variant (LAV) of the bactericidal/permeability-increasing fold-containing family B member 4 (BPIFB4) has been found significantly enriched in long-living individuals. Neuroinflammation is a key player in Huntington’s disease (HD), a neurodegenerative disorder caused by neural death due to expanded CAG repeats encoding a long polyglutamine tract in the huntingtin protein (Htt). Herein, we showed that striatal-derived cell lines with expanded Htt (STHdh Q111/111) expressed and secreted lower levels of BPIFB4, when compared with Htt expressing cells (STHdh Q7/7), which correlated with a defective stress response to proteasome inhibition. Overexpression of LAV-BPIFB4 in STHdh Q111/111 cells was able to rescue both the BPIFB4 secretory profile and the proliferative/survival response. According to a well-established immunomodulatory role of LAV-BPIFB4, conditioned media from LAV-BPIFB4-overexpressing STHdh Q111/111 cells were able to educate Immortalized Human Microglia—SV40 microglial cells. While STHdh Q111/111 dying cells were ineffective to induce a CD163 + IL-10high pro-resolving microglia compared to normal STHdh Q7/7, LAV-BPIFB4 transduction promptly restored the central immune control through a mechanism involving the stromal cell-derived factor-1. In line with the in vitro results, adeno-associated viral-mediated administration of LAV-BPIFB4 exerted a CXCR4-dependent neuroprotective action in vivo in the R6/2 HD mouse model by preventing important hallmarks of the disease including motor dysfunction, body weight loss, and mutant huntingtin protein aggregation. In this view, LAV-BPIFB4, due to its pleiotropic ability in both immune compartment and cellular homeostasis, may represent a candidate for developing new treatment for HD.

scholarly journals Predicting Disease Onset from Mutation Status Using Proband and Relative Data with Applications to Huntington's Disease

2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Tianle Chen ◽  
Yuanjia Wang ◽  
Yanyuan Ma ◽  
Karen Marder ◽  
Douglas R. Langbehn
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Family Member ◽  
Disease Onset ◽  
Repeat Length ◽  
Cag Repeat ◽  
Cag Repeats ◽  
Observational Research ◽  
Accurate Estimation ◽  
Combined Data

Huntington's disease (HD) is a progressive neurodegenerative disorder caused by an expansion of CAG repeats in the IT15 gene. The age-at-onset (AAO) of HD is inversely related to the CAG repeat length and the minimum length thought to cause HD is 36. Accurate estimation of the AAO distribution based on CAG repeat length is important for genetic counseling and the design of clinical trials. In the Cooperative Huntington's Observational Research Trial (COHORT) study, the CAG repeat length is known for the proband participants. However, whether a family member shares the huntingtin gene status (CAG expanded or not) with the proband is unknown. In this work, we use the expectation-maximization (EM) algorithm to handle the missing huntingtin gene information in first-degree family members in COHORT, assuming that a family member has the same CAG length as the proband if the family member carries a huntingtin gene mutation. We perform simulation studies to examine performance of the proposed method and apply the methods to analyze COHORT proband and family combined data. Our analyses reveal that the estimated cumulative risk of HD symptom onset obtained from the combined data is slightly lower than the risk estimated from the proband data alone.

scholarly journals HSF1-dependent and -independent regulation of the mammalian in vivo heat shock response and its impairment in Huntington's disease mouse models

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Andreas Neueder ◽  
Theresa A. Gipson ◽  
Sophie Batterton ◽  
Hayley J. Lazell ◽  
Pamela P. Farshim ◽  
...  
Keyword(s):  
Heat Shock ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Mouse Models ◽  
Heat Shock Response ◽  
Shock Response

scholarly journals Striatal Circuit Development and Its Alterations in Huntington’s Disease

2020 ◽  
Author(s):  
Margaux Lebouc ◽  
Quentin Richard ◽  
Maurice Garret ◽  
Jérôme Baufreton
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Mouse Models ◽  
Neurodegenerative Disorder ◽  
Repeat Expansion ◽  
Cag Repeat ◽  
Rodent Models ◽  
Network Development ◽  
Cag Repeat Expansion ◽  
Circuit Development

Huntington's disease (HD) is an inherited neurodegenerative disorder that usually starts during midlife with progressive alterations of motor and cognitive functions. The disease is caused by a CAG repeat expansion within the huntingtin gene leading to severe striatal neurodegeneration. Recent studies conducted on pre-HD children highlight early striatal developmental alterations starting as soon as 6 years old, the earliest age assessed. These findings, in line with data from mouse models of HD, raise the question of when during development do the first disease-related striatal alterations emerge or whether they contribute to the later appearance of the neurodegenerative features of the disease. In this review we will describe the different stages of striatal network development and then discuss recent evidence for its alterations in rodent models of the disease. We argue that a better understanding of the striatum’s development should help in assessing aberrant neurodevelopmental processes linked to the HD mutation.

scholarly journals Parkinsonism with a Hint of Huntington’s from 29 CAG Repeats in HTT

2019 ◽  
Vol 9 (10) ◽  
pp. 245
Author(s):  
Sipilä JOT
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Clinical Phenotype ◽  
Cag Repeat ◽  
Cag Repeats ◽  
Test Results ◽  
Intermediate Allele ◽  
History Of ◽  
Neurophysiological Test ◽  
History Of Parkinson’S Disease

Huntington’s disease is caused by at least 36 cytosine-adenine-guanine (CAG) repeats in an HTT gene allele, but repeat tracts in the intermediate range (27–35 repeats) also display a subtle phenotype. This patient had a slightly elongated CAG repeat tract (29 repeats), a prominent family history of Parkinson’s disease (PD), and a clinical phenotype mostly consistent with PD, but early dystonia and poor levodopa response. Neurophysiological test results were more consistent with Huntington’s disease (HD) than PD. It is suggested that the intermediate allele modulated the clinical phenotype of PD in this patient.

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