Dentatorubral-pallidoluysian Atrophy Research Articles

Silencing of genes responsible for polyQ diseases using chemically modified single-stranded siRNAs.

Polyglutamine (polyQ) diseases comprise a group of nine genetic disorders that are caused by the expansion of the CAG triplet repeat, which encodes glutamine, in unrelated single genes. Various oligonucleotide (ON)-based therapeutic approaches have been considered for polyQ diseases. The very attractive CAG repeat-targeting strategy offers selective silencing of the mutant allele by directly targeting the mutation site. CAG repeat-targeting miRNA-like siRNAs have been shown to specifically inhibit the mutant gene expression, and their characteristic feature is the formation of mismatches in their interactions with the target site. Here, we designed novel single-stranded siRNAs that contain base substitutions and chemical modifications, in order to develop improved therapeutic tools with universal properties for several polyQ diseases. We tested these ONs in cellular models of Huntington's disease (HD), spinocerebellar ataxia type 3 (SCA3) and dentatorubral-pallidoluysian atrophy (DRPLA). Selected siRNAs caused the efficient and selective downregulation of the mutant huntingtin, ataxin-3 and atrophin-1 levels in cultured human fibroblasts. We also prove the efficiency of novel ONs, with chemical modification pattern mainly containing 2'-fluoro (2'F), in HD mouse striatal cells.

Rescue of ATXN3 neuronal toxicity in Caenorhabditiselegans by chemical modification of endoplasmic reticulum stress.

ABSTRACTPolyglutamine expansion diseases are a group of hereditary neurodegenerative disorders that develop when a CAG repeat in the causative genes is unstably expanded above a certain threshold. The expansion of trinucleotide CAG repeats causes hereditary adult-onset neurodegenerative disorders, such as Huntington's disease, dentatorubral–pallidoluysian atrophy, spinobulbar muscular atrophy and multiple forms of spinocerebellar ataxia (SCA). The most common dominantly inherited SCA is the type 3 (SCA3), also known as Machado–Joseph disease (MJD), which is an autosomal dominant, progressive neurological disorder. The gene causatively associated with MJD is ATXN3. Recent studies have shown that this gene modulates endoplasmic reticulum (ER) stress. We generated transgenic Caenorhabditis elegans strains expressing human ATXN3 genes in motoneurons, and animals expressing mutant ATXN3-CAG89 alleles showed decreased lifespan, impaired movement, and rates of neurodegeneration greater than wild-type ATXN3-CAG10 controls. We tested three neuroprotective compounds (Methylene Blue, guanabenz and salubrinal) believed to modulate ER stress and observed that these molecules rescued ATXN3-CAG89 phenotypes. Furthermore, these compounds required specific branches of the ER unfolded protein response (UPRER), reduced global ER and oxidative stress, and polyglutamine aggregation. We introduce new C. elegans models for MJD based on the expression of full-length ATXN3 in a limited number of neurons. Using these models, we discovered that chemical modulation of the UPRER reduced neurodegeneration and warrants investigation in mammalian models of MJD.

Polyglutamine Diseases after Genetic Analysis in Patients Clinically Diagnosed as Parkinson’s Disease in Bangladesh

Introduction: Polyglutamine (polyQ) diseases are Huntington's Disease (HD), Dentatorubropallidoluysian Atrophy (DRPLA), Spinobulbar Muscle Atrophy (SBMA) and the Spinocerebellar Ataxias (SCA) type 1, 2, 3, 6, 7 and 17. These diseases are characterized by an expansion of the CAG-trinucleotide repeat region in the respective disease-related genes.
 Objective: To find out Polyglutamine (polyQ) diseases by genetic analysis from those patients presenting with Parkinsonism in the Neurology department of Mymensingh Medical College hospital.
 Materials and Methods: This study was conducted on 7 healthy people and 9 patients of Neurology Department, Mymensingh Medical College Hospital in 2010. 5ml blood was collected from each individual by venipuncture. The complaints of patients along with physical and/or psychological findings, family history including demographic data were recorded with a questionnaire by the neurologists of Hospital. Informed consents from the patients were taken and ethical clearance sought as well. Extraction of genomic DNA from the venous blood using FlexiGene DNA kit (Qiagen, Japan) was performed in Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh, Bangladesh. The extracted DNA was stored, accumulated and were sent to Division of Clinical Genetics, Department of Medical Genetics, Osaka University Medical School, Suita, Osaka 565 0871, Japan for PCR and further analysis up to amplification.
 Results: HD PCR products reveal the DNA product of about 110bp (no. of CAG repeats=21) to 150bp (no. of CAG repeats=34) in both healthy individual and patient repeats=36). SCA2 PCR products reveal the DNA products of about 150 bp (no. of CAG repeats=23) except one patient and it was 175bp (no. of CAG repeats=30). SCA3 PCR product size of both healthy individual and patient DNA was within about 250 (no. of CAG=11) to 300 bp (no. of CAG repeats=28) except one patient which was about 320bp and its CAG repeats was about 34. SCA6 PCR product size of both healthy individual and patient DNA was about 150bp (no. of CAG=16). DRPLA PCR product size of healthy individual and patients DNA was about 142 (no. of CAG repeats=19) to 165bp (no. of CAG repeats=27) except one healthy individual DNA which was about 205 bp and its CAG repeat was 40.
 Conclusion: Genetic analysis and PCR has been an important tool to visualize the root cause of the diseasesthe CAG repeat can facilitate a definitive clue to address Poly Q diseases.This is so far first time study in Bangladesh on the range of CAG repeats in patients as well as healthy individual.
 Journal of Armed Forces Medical College Bangladesh Vol.12(2) 2016: 44-49

Modulation of Molecular Chaperones in Huntington's Disease and Other Polyglutamine Disorders.

Polyglutamine expansion mutations in specific proteins underlie the pathogenesis of a group of progressive neurodegenerative disorders, including Huntington's disease, spinal and bulbar muscular atrophy, dentatorubral-pallidoluysian atrophy, and several spinocerebellar ataxias. The different mutant proteins share ubiquitous expression and abnormal proteostasis, with misfolding and aggregation, but nevertheless evoke distinct patterns of neurodegeneration. This highlights the relevance of the full protein context where the polyglutamine expansion occurs and suggests different interactions with the cellular proteostasis machinery. Molecular chaperones are key elements of the proteostasis machinery and therapeutic targets for neurodegeneration. Here, we provide a focused review on Hsp90, Hsp70, and their co-chaperones, and how their genetic or pharmacological modulation affects the proteostasis and disease phenotypes in cellular and animal models of polyglutamine disorders. The emerging picture is that, in principle, Hsp70 modulation may be more amenable for long-term treatment by promoting a more selective clearance of mutant proteins than Hsp90 modulation, which may further decrease the necessary wild-type counterparts. It seems, nevertheless, unlikely that a single Hsp70 modulator will benefit all polyglutamine diseases. Indeed, available data, together with insights from effects on tau and alpha-synuclein in models of Alzheimer's and Parkinson's diseases, indicates that Hsp70 modulators may lead to different effects on the proteostasis of different mutant and wild-type client proteins. Future studies should include the further development of isoform selective inhibitors, namely to avoid off-target effects on Hsp in the mitochondria, and their characterization in distinct polyglutamine disease models to account for client protein-specific differences.

Widening the Spectrum of Extra-Neuromuscular Involvement in SBMA: Is there a Role for Brain Pathology?

J Neurol Stroke 2016, 5(1): 00164 also includes Huntington’s disease, dentatorubral-pallidoluysian atrophy, and spinocerebellar ataxia (SCA) types 1, 2, 3, 6, 7, and 17. Within the family of polyglutamine diseases, SBMA is unique in its gender-specificity, with full disease manifestation restricted to males. Since the disease is ligand (androgen)-dependent, SBMA manifests primarily in males, which have high levels of circulating androgens in the serum, while females are usually asymptomatic [4]. Indeed, the polyglutamine-expanded AR is converted to a neurotoxic species upon binding to androgens [5].

MR Imaging in Spinocerebellar Ataxias: A Systematic Review.

Polyglutamine expansion spinocerebellar ataxias are autosomal dominant slowly progressive neurodegenerative diseases with no current treatment. MR imaging is the best-studied surrogate biomarker candidate for polyglutamine expansion spinocerebellar ataxias, though with conflicting results. We aimed to review quantitative central nervous system MR imaging technique findings in patients with polyglutamine expansion spinocerebellar ataxias and correlations with well-established clinical and molecular disease markers. We searched MEDLINE, LILACS, and Cochrane data bases of clinical trials between January 1995 and January 2016, for quantitative MR imaging volumetric approaches, MR spectroscopy, diffusion tensor imaging, or other quantitative techniques, comparing patients with polyglutamine expansion spinocerebellar ataxias (SCAs) with controls. Pertinent details for each study regarding participants, imaging methods, and results were extracted. After reviewing the 706 results, 18 studies were suitable for inclusion: 2 studies in SCA1, 1 in SCA2, 15 in SCA3, 1 in SCA7, 1 in SCA1 and SCA6 presymptomatic carriers, and none in SCA17 and dentatorubropallidoluysian atrophy. Cerebellar hemispheres and vermis, whole brain stem, midbrain, pons, medulla oblongata, cervical spine, striatum, and thalamus presented significant atrophy in SCA3. The caudate, putamen and whole brain stem presented similar sensitivity to change compared with ataxia scales after 2 years of follow-up in a single prospective study in SCA3. MR spectroscopy and DTI showed abnormalities only in cross-sectional studies in SCA3. Results from single studies in other polyglutamine expansion spinocerebellar ataxias should be replicated in different cohorts. Additional cross-sectional and prospective volumetric analysis, MR spectroscopy, and DTI studies are necessary in polyglutamine expansion spinocerebellar ataxias. The properties of preclinical disease biomarkers (presymptomatic) of MR imaging should be targeted in future studies.

長期経過観察をした歯状核赤核淡蒼球ルイ体萎縮症 (DRPLA) の28歳女性

長期経過観察をした歯状核赤核淡蒼球ルイ体萎縮症 (DRPLA) の28歳女性

Identification of common therapeutic targets for selected neurodegenerative disorders: An in silico approach

Neurodegenerative disorders (NDs) are a heterogeneous group of disorders generally characterized by a profound decrease in the size and volume of the human brain due to death of neurons. These disorders include a variety of progressive disorders that result in cognitive and/or motor degradation. The present study was conducted to identify common potential targets for multi-neurodegenerative diseases. To accomplish this, we have selected six common neurodegenerative diseases, Alzheimer’s disease (AD), Parkinson’s disease (PD), Amyotrophic lateral sclerosis (ALS), Huntington’s disease (HD), Prion disease and Dentatorubral-pallidoluysian atrophy (DRPLA) for identification of common regulatory target proteins. A total of sixteen common proteins were identified as target proteins by disease pathway analysis and previous studies based on their association with more than two NDs, including AD. An interaction network of each of the sixteen target proteins was then constructed against causative proteins selected from all six NDs by using the STRING 9.1 program. Pathway analysis and the protein–protein interaction network suggested that CASP-3 and CASP-8 were associated with the maximum number of selected NDs and may therefore be the most potent target proteins for treatment of multi-neurodegenerative diseases.

Huntington's Disease, Huntington's Disease Look-Alikes‎, and Benign Hereditary Chorea: What's New?

The differential diagnosis of chorea syndromes is complex. It includes inherited forms, the most common of which is autosomal dominant Huntington's disease (HD). In addition, there are disorders mimicking HD, the so-called HD-like (HDL) syndromes. Here we review main clinical, genetic, and pathophysiological characteristics of HD and the rare HD phenocopies in order to familiarize clinicians with them. Molecular studies have shown that HD phenocopies account for about 1% of suspected HD cases, most commonly due to mutations in C9orf72 (also the main cause of frontotemporal dementia and amyotrophic lateral sclerosis syndromes), TATA box-binding protein (spinocerebellar ataxia type 17 [SCA17]/HDL4), and JPH3 (HDL2). Systematic screening studies also revealed mutations in PRNP (prion disease), VPS13A (chorea-acanthocytosis), ATXN8OS-ATXN8 (SCA8), and FXN (late-onset Friedreich's Ataxia) in single cases. Further differential diagnoses to consider in patients presenting with a clinical diagnosis consistent with HD, but without the HD expansion, include dentatorubral-pallidoluysian atrophy and benign hereditary chorea (TITF1), as well as the recently described form of ADCY5-associated neurodegeneration. Lastly, biallelic mutations in RNF216 and FRRS1L have recently been reported as autosomal recessive phenocopies of HD. There is a growing list of genes associated with chorea, yet a substantial percentage of patients remain undiagnosed. It is likely that more genes will be discovered in the future and that the clinical spectrum of the described disorders will broaden.

Striatal glucose hypometabolism in preadolescent-onset dentatorubral–pallidoluysian atrophy

Dentatorubral–pallidoluysian atrophy (DRPLA) is hereditary spinocerebellar degeneration presenting various symptoms in association with expansion of the CAG repeat in Atrophin-1 gene. The functional neuroimaging of DRPLA has been poorly investigated. The purpose of this study was to examine 18F-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) findings of DRPLA. We retrospectively investigated the cases of 14 consecutive genetically confirmed DRPLA patients at our institute. Four juvenile-onset patients underwent 18F-FDG-PET because of intractable seizures. Their 18F-FDG-PET images, clinical profiles and MRI findings were evaluated. For quantitative comparison, 3 healthy volunteers also underwent 18F-FDG-PET as controls. All four patients presented progressive myoclonus epilepsy without MRI abnormalities. Both the visual and quantitative assessments of their 18F-FDG-PET findings demonstrated bistriatal hypometabolism in only the two preadolescent-onset patients with larger CAG repeat size, whereas the two other later-onset patients showed no hypometabolism in the striatum. Bistriatal glucose hypometabolism in preadolescent-onset DRPLA patients might reflect more severe degeneration. This finding could contribute to a better understanding of DRPLA.

Spinocerebellar ataxias in Venezuela: genetic epidemiology and their most likely ethnic descent.

Dominantly inherited ataxias (spinocerebellar ataxias, SCAs) are a genetically heterogeneous group of neurologic diseases characterized by progressive cerebellar and spinal tract degeneration with ataxia and other signs, common to all known subtypes. Several types are relatively frequent worldwide, but in several countries, one specific SCA may show a higher prevalence owing to founder phenomena. In Venezuela, genetic epidemiological features of SCAs have been assessed during the last 30 years; mutations in ATXN1 (SCA1), ATXN2 (SCA2), ATXN3 (SCA3), CACNA1A (SCA6), ATXN7 (SCA7), ATXN8 (SCA8), ATXN10 (SCA10), TBP (SCA17) and ATN1 (dentatorubral pallidoluysian atrophy, DRPLA) loci were searched among 115 independent families. SCA7 was the most frequent subtype (26.6%), followed by SCA3 (25.0%), SCA2 (21.9%), SCA1 (17.2%), SCA10 (4.7%) and DRPLA (3.1%); in 43% of the families, the subtype remained unidentified. SCA7 mutations displayed strong geographic aggregation in two independent founder foci, and SCA1 showed a very remote founder effect for a subset of families. SCA10 families were scattered across the country, but all had an identical in-phase haplotype carried also by Mexican, Brazilian and Sioux patients, supporting a very old common Amerindian origin. Prevalence for dominant SCAs in Venezuela was estimated as 1:25 000 nuclear families, provenances of which are either Caucasoid, African or Amerindian.

Analysis of SCA8, SCA10, SCA12, SCA17 and SCA19 in patients with unknown spinocerebellar ataxia: a Thai multicentre study.

BackgroundAbout 50 % of Thai patients with adult-onset spinocerebellar ataxia (SCA) was Machado-Joseph disease (MJD), SCA1, SCA2 and SCA6. The author investigated further on less common SCAs in the patients without any known mutations.MethodsDNA samples of 82 index patients who were genetically excluded MJD, SCA1, SCA2, SCA6, SCA7 and dentatorubro-pallidoluysian atrophy (DRPLA) were examined. Analysis of SCA8, SCA10, SCA12, SCA17 and SCA19 genes were comprehensively performed. Normal range of trinucleotide repeat expansion sizes of TATA-box-binding protein gene (TBP) were also determined in 374 control subjects.ResultsEight patients carried ≥42 CAG/CAA repeat allele in the TBP consistent with SCA17. The pathological repeat alleles ranged from 42 to 57 repeats. All patients had significant degree of cognitive dysfunction. Other non-ataxic phenotypes comprised of parkinsonism, chorea, dystonia and myoclonus. A sporadic patient carried a heterozygous 41-repeat allele developed chronic progressive cerebellar degeneration commenced at the age of 28 years. Whilst, 2 % of the control subjects (8/374) carried the 41-repeat allele. Five of the carriers were re-examined, and revealed that four of them had parkinsonism and/or cognitive impairment without cerebellar signs. Analysis of other types of SCAs was all negative.ConclusionsThis is the first study of SCA8, SCA10, SCA12, SCA17 and SCA19 in Thais. SCA17 appears to be an important cause of ataxia in Thailand. Although, the pathological cut-off point of the TBP repeat allele remains unclear, the finding suggests that the 41-repeat may be a pathological allele resulting late-onset or mild phenotype. Apart from ataxia, cognitive impairment and parkinsonism may be clinical presentations in these carriers.Electronic supplementary materialThe online version of this article (doi:10.1186/s12883-015-0425-y) contains supplementary material, which is available to authorized users.

G protein-coupled receptor 26 immunoreactivity in intranuclear inclusions associated with polyglutamine and intranuclear inclusion body diseases.

G protein-coupled receptor 26 (GPR26) is one of the G-protein-coupled receptors (GPCRs), which comprise the largest family of membrane proteins and mediate most of the physiological responses to hormones, neurotransmitters and environmental stimulants. Although GPCRs are considered to play an important role in the pathophysiology of neurodegenerative disorders, it is uncertain whether GPR26 is involved in the pathogenesis of polyglutamine and intranuclear inclusion body diseases. We immunohistochemically examined the brain tissues of patients with four polyglutamine diseases (Huntington's disease, dentatorubral-pallidoluysian atrophy, and spinocerebellar ataxia types 1 and 3) and intranuclear inclusion body disease, and normal control subjects. In controls, anti-GPR26 antibody immunolabeled the neuronal cytoplasm in a diffuse granular pattern. Neuronal nuclear inclusions in polyglutamine diseases were immunopositive for GPR26. In intranuclear inclusion body disease, GPR26-positive nuclear inclusions were found in both neurons and glial cells. Marinesco bodies in aged control subjects were also positive for GPR26. Double immunofluorescence analysis revealed co-localization of GPR26 with polyglutamine or ubiquitin in these nuclear inclusions. These findings suggest that GPR26 may have a common role in the formation or degradation of intranuclear inclusions in several neurodegenerative diseases.

Progressive Myoclonus Epilepsy with Adolescent Onset: Clinical Features and Diagnosis

Many of the progressive epilepsy syndromes with adolescent onset are classified as progressive myoclonus epilepsies. It is a heterogenous group of epilepsy syndromes associated with seizure, myoclonus, and progressive neurologic decline. This review focuses on the different adolescent-onset progressive myoclonus epilepsies including Unverricht–Lundborg disease, Lafora disease, juvenile-onset neuronal ceroid lipofuscinosis, sialidosis (cherry-red spot myoclonus), dentatorubral–pallidoluysian atrophy, and myoclonic epilepsy and ragged-red fibers. Their clinical presentations, neurophysiologic and neuroimaging findings, genetics, pathology, and diagnosis are discussed.

Transfer of genetic therapy across human populations: molecular targets for increasing patient coverage in repeat expansion diseases.

Allele-specific gene therapy aims to silence expression of mutant alleles through targeting of disease-linked single-nucleotide polymorphisms (SNPs). However, SNP linkage to disease varies between populations, making such molecular therapies applicable only to a subset of patients. Moreover, not all SNPs have the molecular features necessary for potent gene silencing. Here we provide knowledge to allow the maximisation of patient coverage by building a comprehensive understanding of SNPs ranked according to their predicted suitability toward allele-specific silencing in 14 repeat expansion diseases: amyotrophic lateral sclerosis and frontotemporal dementia, dentatorubral-pallidoluysian atrophy, myotonic dystrophy 1, myotonic dystrophy 2, Huntington's disease and several spinocerebellar ataxias. Our systematic analysis of DNA sequence variation shows that most annotated SNPs are not suitable for potent allele-specific silencing across populations because of suboptimal sequence features and low variability (>97% in HD). We suggest maximising patient coverage by selecting SNPs with high heterozygosity across populations, and preferentially targeting SNPs that lead to purine:purine mismatches in wild-type alleles to obtain potent allele-specific silencing. We therefore provide fundamental knowledge on strategies for optimising patient coverage of therapeutics for microsatellite expansion disorders by linking analysis of population genetic variation to the selection of molecular targets.

Inherited Ataxias

The inherited ataxias are disorders that cause progressive imbalance as a result of pathology in the cerebellum and its various connecting pathways. Autosomal recessive ataxias include Friedreich ataxia, ataxia with isolated vitamin E deficiency, ataxia-telangiectasia, and autosomal recessive ataxia of Charlevoix-Saguenay, among others. A discussion of autosomal dominant ataxias covers spinocerebellar ataxias (SCA) types 1 through 14, dentatorubral pallidoluysian atrophy (DRPLA), and episodic ataxia (EA) syndromes. Clinical features, laboratory studies, differential diagnosis, and management of inherited ataxias are discussed. Tables describe both autosomal recessive ataxias and autosomal dominant ataxias (with known gene loci), childhood– or young adult–onset ataxias with ill-defined genetic abnormalities, phenotypic features that may indicate a specific genotype in the common autosomal dominant ataxias, and normal and expanded ranges of various repetitive nucleotide sequences in inherited ataxias. Figures include a diagrammatic representation of the type of repeat expansions associated with ataxias, aggregates of ataxin 3, a schematic of some of the proposed pathogenic mechanisms in the polyglutamine ataxias, and dystonia in a patient with SCA3. A sidebar offers selected Internet resources for information on ataxias. This chapter contains 64 references.

An understanding of spinocerebellar ataxia.

An understanding of spinocerebellar ataxia.

Long-term clinical course of eight cases of childhood-onset juvenile dentatorubropallidoluysian atrophy up to adulthood.

Long-term clinical course of eight cases of childhood-onset juvenile dentatorubropallidoluysian atrophy up to adulthood.

Molecular genetic analysis of trinucleotide repeat disorders (TRDs) in Indian population and application of repeat primed PCR

Trinucleotide repeat disorders (TRDs) are a set of genetic disorders caused by trinucleotide repeat expansion in certain genes that exceed the normal, stable threshold, which varies from gene to gene. A dynamic mutation in a healthy gene may increase the repeat count and result in a defective gene. At present there are 14 pathogenic trinucleotide repeat disorders that are known to affect humans. The occurrence of these “triplet repeat diseases” within populations ranges from fairly common (Fragile X syndrome and Myotonic dystrophy type 1) to rare (Dentatorubral-pallidoluysian atrophy). In the present study we report a detailed scenario of TRDs in India mostly in respect to the 9 most common disorders namely; Fragile X syndrome, Myotonic dystrophy type 1, Spinocerebellar ataxia (type 1, 2, 3, 6 and 7), Friedreich Ataxia and Huntington Disease.

Epigenetic regulation of Atrophin1 by lysine-specific demethylase 1 is required for cortical progenitor maintenance.

Lysine-specific demethylase 1 (LSD1) is involved in gene regulation and development; however, its precise function, molecular targets and underlying mechanisms during development are poorly understood. Here we show that LSD1 is required for neuronal progenitor cell (NPC) maintenance during cortical development. A ChIP-seq analysis identified a LSD1-binding site (LBAL) downstream of Atrophin1 (ATN1). Surprisingly, tranylcypromine (LSD1 inhibitor) treatment increased H3K4 methylation at LBAL, leading to ATN1 repression and NPC differentiation. Knockdown of LSD1 and ATN1 phenocopied each other in inducing NPC premature differentiation and depletion, which could be rescued by ATN1 overexpression, suggesting that LSD1 controls NPC differentiation via regulation of ATN1 methylation status and expression. The involvement of LSD1 in ATN1 expression and NPC maintenance were confirmed in knockout mice. These findings hint at the potential application for the clinical drug, tranylcypromine, in the prevention and/or treatment of ATN1-associated degenerative disease, dentatorubral-pallidoluysian atrophy.