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1.
Disabil Rehabil ; 43(1): 85-97, 2021 01.
Article in English | MEDLINE | ID: mdl-31131641

ABSTRACT

PURPOSE: Evidence is increasing for effective virtual reality therapy for motor rehabilitation for children with Cerebral Palsy. We assessed the feasibility of a virtual reality therapy mode of intervention, appropriateness of measures, and potential cost-effectiveness. METHODS: A 12-week, 2-group, parallel-feasibility trial (ISRCT 17624388) using Nintendo Wii FitTM at home. Children aged 5-16, with ambulatory Cerebral Palsy, who were able to follow simple instructions were randomised to two groups; one supported by physiotherapists (individualised activity programme), the other unsupported with children having free choice (control). Children were assessed in clinic at baseline, week 6, and week 12 by blinded assessors. Feasibility of the intervention was assessed via recruitment, adherence, and usefulness of measurement tools. RESULTS: Forty-four children were eligible (out of 48 approached): 31 consented, 30 were randomised, 21 completed the study; 10 in the supported group and 11 in the unsupported group. Nine children discontinued from tiredness, after-school activities, homework, surgery, technical difficulties or negative system feedback. The supported group completed 19 of 36 (IQR 5-35) possible sessions; the unsupported group 24 of 36 sessions (IQR 8-36). Gross Motor Function Measure scores varied by Cerebral Palsy severity after the intervention. There were no adverse events. CONCLUSION: Virtual reality therapy offers potential as a therapeutic adjunct for children with Cerebral Palsy, warranting substantive confirmatory study. Gross Motor Function Measure, with modifications to improve sensitivity, appeared appropriate as a primary measure, with Timed up and Go test secondary. The intervention was inexpensive costing £20 per child. An explanatory trial to evaluate the clinical/cost-effectiveness of commercial system virtual reality therapy is feasible with minor methodological adaptation. Implications for rehabilitation Home-based interactive computer gaming was feasible, safe and cost effective as a therapy adjunct. Discontinue if additional pressures are present: imminent surgery, family resilience to technical difficulties, negative system feedback, after-school activities. Change in Gross Motor Function Measurement scores varied by severity of Cerebral Palsy.


Subject(s)
Cerebral Palsy , Virtual Reality Exposure Therapy , Adolescent , Cerebral Palsy/therapy , Child , Child, Preschool , Feasibility Studies , Humans , Postural Balance , Time and Motion Studies
2.
Proc Natl Acad Sci U S A ; 115(52): E12407-E12416, 2018 12 26.
Article in English | MEDLINE | ID: mdl-30530649

ABSTRACT

The genetically heterogeneous spinocerebellar ataxias (SCAs) are caused by Purkinje neuron dysfunction and degeneration, but their underlying pathological mechanisms remain elusive. The Src family of nonreceptor tyrosine kinases (SFK) are essential for nervous system homeostasis and are increasingly implicated in degenerative disease. Here we reveal that the SFK suppressor Missing-in-metastasis (MTSS1) is an ataxia locus that links multiple SCAs. MTSS1 loss results in increased SFK activity, reduced Purkinje neuron arborization, and low basal firing rates, followed by cell death. Surprisingly, mouse models for SCA1, SCA2, and SCA5 show elevated SFK activity, with SCA1 and SCA2 displaying dramatically reduced MTSS1 protein levels through reduced gene expression and protein translation, respectively. Treatment of each SCA model with a clinically approved Src inhibitor corrects Purkinje neuron basal firing and delays ataxia progression in MTSS1 mutants. Our results identify a common SCA therapeutic target and demonstrate a key role for MTSS1/SFK in Purkinje neuron survival and ataxia progression.


Subject(s)
Microfilament Proteins/metabolism , Neoplasm Proteins/metabolism , Spinocerebellar Ataxias/genetics , Spinocerebellar Ataxias/physiopathology , Animals , Ataxia/pathology , Disease Models, Animal , Humans , Mice , Mice, Inbred C57BL , Microfilament Proteins/genetics , Neoplasm Proteins/genetics , Proteins/metabolism , Purkinje Cells/physiology , Spinocerebellar Ataxias/metabolism , Spinocerebellar Degenerations/metabolism , Spinocerebellar Degenerations/physiopathology , src-Family Kinases/metabolism
3.
Hum Mol Genet ; 27(15): 2614-2627, 2018 08 01.
Article in English | MEDLINE | ID: mdl-29741614

ABSTRACT

Loss of excitatory amino acid transporters (EAATs) has been implicated in a number of human diseases including spinocerebellar ataxias, Alzhiemer's disease and motor neuron disease. EAAT4 and GLAST/EAAT1 are the two predominant EAATs responsible for maintaining low extracellular glutamate levels and preventing neurotoxicity in the cerebellum, the brain region essential for motor control. Here using genetically modified mice we identify new critical roles for EAAT4 and GLAST/EAAT1 as modulators of Purkinje cell (PC) spontaneous firing patterns. We show high EAAT4 levels, by limiting mGluR1 signalling, are essential in constraining inherently heterogeneous firing of zebrin-positive PCs. Moreover mGluR1 antagonists were found to restore regular spontaneous PC activity and motor behaviour in EAAT4 knockout mice. In contrast, GLAST/EAAT1 expression is required to sustain normal spontaneous simple spike activity in low EAAT4 expressing (zebrin-negative) PCs by restricting NMDA receptor activation. Blockade of NMDA receptor activity restores spontaneous activity in zebrin-negative PCs of GLAST knockout mice and furthermore alleviates motor deficits. In addition both transporters have differential effects on PC survival, with zebrin-negative PCs more vulnerable to loss of GLAST/EAAT1 and zebrin-positive PCs more vulnerable to loss of EAAT4. These findings reveal that glutamate transporter dysfunction through elevated extracellular glutamate and the aberrant activation of extrasynaptic receptors can disrupt cerebellar output by altering spontaneous PC firing. This expands our understanding of disease mechanisms in cerebellar ataxias and establishes EAATs as targets for restoring homeostasis in a variety of neurological diseases where altered cerebellar output is now thought to play a key role in pathogenesis.


Subject(s)
Cerebellum/metabolism , Excitatory Amino Acid Transporter 1/genetics , Excitatory Amino Acid Transporter 4/genetics , Purkinje Cells/physiology , Animals , Ataxia/genetics , Cell Survival/genetics , Excitatory Amino Acid Transporter 1/metabolism , Excitatory Amino Acid Transporter 4/metabolism , Female , Male , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Nerve Tissue Proteins/metabolism , Purkinje Cells/cytology , Receptors, Metabotropic Glutamate/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism
4.
Sci Rep ; 7(1): 17467, 2017 12 12.
Article in English | MEDLINE | ID: mdl-29234100

ABSTRACT

Close contacts between the endoplasmic reticulum membrane and the mitochondrial outer membrane facilitate efficient transfer of lipids between the organelles and coordinate Ca2+ signalling and stress responses. Changes to this coupling is associated with a number of metabolic disorders and neurodegenerative diseases including Alzheimer's, Parkinson's and motor neuron disease. The distance between the two membranes at regions of close apposition is below the resolution of conventional light microscopy, which makes analysis of these interactions challenging. Here we describe a new bifluorescence complementation (BiFC) method that labels a subset of ER-mitochondrial associations in fixed and living cells. The total number of ER-mitochondria associations detected by this approach increases in response to tunicamycin-induced ER stress, serum deprivation or reduced levels of mitofusin 2 (MFN2). This method will facilitate the analysis of dynamic interactions between the ER and mitochondrial membranes.


Subject(s)
Endoplasmic Reticulum/metabolism , Luminescent Proteins/metabolism , Microscopy, Fluorescence/methods , Mitochondria/metabolism , Animals , COS Cells , Cell Line, Tumor , Chlorocebus aethiops , Endoplasmic Reticulum Stress , HEK293 Cells , Humans , Immunohistochemistry , Luminescent Proteins/genetics , Mice , Microscopy, Confocal/methods , Transfection
5.
BMJ Open ; 7(7): e013944, 2017 Jul 09.
Article in English | MEDLINE | ID: mdl-28694340

ABSTRACT

OBJECTIVES: To characterise the pattern of colonisation and serotypes of Streptococcus pneumoniae among patients with chronic obstructive pulmonary disease (COPD) who currently receive the 23-valent pneumococcal polysaccharide vaccine (PPV-23) according to vaccination status, use of antibiotics and steroids. To investigate the prevalence of PPV-23 and 13-valent pneumococcal conjugate vaccine (PCV-13) serotypes within the study cohort. DESIGN: A non-interventional, observational, prospective cohort study with a 12 -month follow-up period inclusive of quarterly study visits. SETTING: Beaumont Hospital and The Royal College of Surgeons in Ireland Clinical Research Centre, Dublin, Ireland. PARTICIPANTS: Patients with an established diagnosis of COPD attending a tertiary medical centre. PRIMARY OUTCOME MEASURE: Colonisation rate of S. pneumoniae in patients with COPD and characterisation of serotypes of S. pneumoniae with correlation to currently available pneumococcal vaccines. Sputum and oropharyngeal swab samples were collected for the isolation of S. pneumoniae. SECONDARY OUTCOME MEASURE: Seasonality of colonisation of S. pneumoniae and its relationship with the incidence of exacerbations of COPD. RESULTS: S. pneumoniae was detected in 16 of 417 samples, a colonisation incident rate of 3.8% and in 11 of 133 (8%) patients at least once during the study. The majority of S. pneumoniae isolates were identified in spring and were non-vaccine serotypes for either the PPV-23 or PCV-13 (63%). The colonisation incident rate of S. pneumoniae fluctuated over the four seasons with a peak of 6.6% in spring and the lowest rate of 2.2% occurring during winter. Antibiotic use was highest during periods of low colonisation. CONCLUSIONS: There is seasonal variation in S. pneumoniae colonisation among patients with COPD which may reflect antibiotic use in autumn and winter. The predominance of non-vaccine types suggests that PCV-13 may have limited impact among patients with COPD in Ireland who currently receive PPV-23. TRIAL REGISTRATION NUMBER: NCT02535546; post-results.


Subject(s)
Pneumococcal Infections/epidemiology , Pneumococcal Vaccines/therapeutic use , Pulmonary Disease, Chronic Obstructive/complications , Seasons , Aged , Anti-Bacterial Agents/therapeutic use , Disease Progression , Female , Humans , Incidence , Ireland , Male , Middle Aged , Pneumococcal Infections/prevention & control , Prospective Studies , Pulmonary Disease, Chronic Obstructive/microbiology , Sputum/microbiology , Streptococcus pneumoniae , Vaccines, Conjugate/therapeutic use
6.
Am J Hum Genet ; 100(5): 706-724, 2017 May 04.
Article in English | MEDLINE | ID: mdl-28413018

ABSTRACT

During neurotransmission, synaptic vesicles undergo multiple rounds of exo-endocytosis, involving recycling and/or degradation of synaptic proteins. While ubiquitin signaling at synapses is essential for neural function, it has been assumed that synaptic proteostasis requires the ubiquitin-proteasome system (UPS). We demonstrate here that turnover of synaptic membrane proteins via the endolysosomal pathway is essential for synaptic function. In both human and mouse, hypomorphic mutations in the ubiquitin adaptor protein PLAA cause an infantile-lethal neurodysfunction syndrome with seizures. Resulting from perturbed endolysosomal degradation, Plaa mutant neurons accumulate K63-polyubiquitylated proteins and synaptic membrane proteins, disrupting synaptic vesicle recycling and neurotransmission. Through characterization of this neurological intracellular trafficking disorder, we establish the importance of ubiquitin-mediated endolysosomal trafficking at the synapse.


Subject(s)
Epilepsy/genetics , Proteins/genetics , Spasms, Infantile/genetics , Synaptic Transmission , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Animals , Disease Models, Animal , Epilepsy/diagnosis , Fibroblasts/metabolism , Genotyping Techniques , Humans , Infant , Infant, Newborn , Magnetic Resonance Imaging , Mice , Mice, Transgenic , Mutation , Proteasome Endopeptidase Complex/genetics , Proteasome Endopeptidase Complex/metabolism , Protein Conformation , Proteins/metabolism , Purkinje Cells/metabolism , Spasms, Infantile/diagnosis , Synaptic Vesicles/metabolism , Transcriptome , Ubiquitin/genetics , Ubiquitin/metabolism
7.
Am J Respir Crit Care Med ; 195(10): 1333-1343, 2017 05 15.
Article in English | MEDLINE | ID: mdl-27409253

ABSTRACT

RATIONALE: Objective adherence to inhaled therapy by patients with chronic obstructive pulmonary disease (COPD) has not been reported. OBJECTIVES: To objectively quantify adherence to preventer Diskus inhaler therapy by patients with COPD with an electronic audio recording device (INCA). METHODS: This was a prospective observational study. On discharge from hospital patients were given a salmeterol/fluticasone inhaler with an INCA device attached. Analysis of this audio quantified the frequency and proficiency of inhaler use. MEASUREMENTS AND MAIN RESULTS: Patients with COPD (n = 244) were recruited. The mean age was 71 years, mean FEV1 was 1.3 L, and 59% had evidence of mild/moderate cognitive impairment. By combining time of use, interval between doses, and critical technique errors, thus incorporating both intentional and unintentional nonadherence, a measure "actual adherence" was calculated. Mean actual adherence was 22.6% of that expected if the doses were taken correctly and on time. Six percent had an actual adherence greater than 80%. Hierarchical clustering found three equally sized well-separated clusters corresponding to distinct patterns. Cluster 1 (34%) had low inhaler use and high error rates. Cluster 2 (25%) had high inhaler use and high error rates. Cluster 3 (36%) had overall good adherence. Poor lung function and comorbidities were predictive of poor technique, whereas age and cognition with poor lung function distinguished those with poor adherence and frequent errors in technique. CONCLUSIONS: These data may inform clinicians in understanding why a prescribed inhaler is not effective and to devise strategies to promote adherence in COPD.


Subject(s)
Bronchodilator Agents/administration & dosage , Nebulizers and Vaporizers , Patient Compliance/statistics & numerical data , Pulmonary Disease, Chronic Obstructive/drug therapy , Administration, Inhalation , Aged , Bronchodilator Agents/therapeutic use , Drug Combinations , Female , Fluticasone/administration & dosage , Humans , Male , Prospective Studies , Salmeterol Xinafoate/administration & dosage , Salmeterol Xinafoate/therapeutic use
8.
J Physiol ; 594(16): 4661-76, 2016 08 15.
Article in English | MEDLINE | ID: mdl-26821241

ABSTRACT

Spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of disorders all characterised by postural abnormalities, motor deficits and cerebellar degeneration. Animal and in vitro models have revealed ß-III spectrin, a cytoskeletal protein present throughout the soma and dendritic tree of cerebellar Purkinje cells, to be required for the maintenance of dendritic architecture and for the trafficking and/or stabilisation of several membrane proteins: ankyrin-R, cell adhesion molecules, metabotropic glutamate receptor-1 (mGluR1), voltage-gated sodium channels (Nav ) and glutamate transporters. This scaffold of interactions connects ß-III spectrin to a wide variety of proteins implicated in the pathology of many SCAs. Heterozygous mutations in the gene encoding ß-III spectrin (SPTBN2) underlie SCA type-5 whereas homozygous mutations cause spectrin associated autosomal recessive ataxia type-1 (SPARCA1), an infantile form of ataxia with cognitive impairment. Loss-of ß-III spectrin function appears to underpin cerebellar dysfunction and degeneration in both diseases resulting in thinner dendrites, excessive dendritic protrusion with loss of planarity, reduced resurgent sodium currents and abnormal glutamatergic neurotransmission. The initial physiological consequences are a decrease in spontaneous activity and excessive excitation, likely to be offsetting each other, but eventually hyperexcitability gives rise to dark cell degeneration and reduced cerebellar output. Similar molecular mechanisms have been implicated for SCA1, 2, 3, 7, 13, 14, 19, 22, 27 and 28, highlighting alterations to intrinsic Purkinje cell activity, dendritic architecture and glutamatergic transmission as possible common mechanisms downstream of various loss-of-function primary genetic defects. A key question for future research is whether similar mechanisms underlie progressive cerebellar decline in normal ageing.


Subject(s)
Cerebellar Ataxia/physiopathology , Spectrin/physiology , Animals , Cerebellar Ataxia/genetics , Cognitive Dysfunction/genetics , Cognitive Dysfunction/physiopathology , Humans , Mutation , Spectrin/genetics
9.
Hum Mol Genet ; 25(20): 4448-4461, 2016 10 15.
Article in English | MEDLINE | ID: mdl-28173092

ABSTRACT

Clinical phenotypes of spinocerebellar ataxia type-5 (SCA5) and spectrin-associated autosomal recessive cerebellar ataxia type-1 (SPARCA1) are mirrored in mice lacking ß-III spectrin (ß-III-/-). One function of ß-III spectrin is the stabilization of the Purkinje cell-specific glutamate transporter EAAT4 at the plasma membrane. In ß-III-/- mice EAAT4 levels are reduced from an early age. In contrast levels of the predominant cerebellar glutamate transporter GLAST, expressed in Bergmann glia, only fall progressively from 3 months onwards. Here we elucidated the roles of these two glutamate transporters in cerebellar pathogenesis mediated through loss of ß-III spectrin function by studying EAAT4 and GLAST knockout mice as well as crosses of both with ß-III-/- mice. Our data demonstrate that EAAT4 loss, but not abnormal AMPA receptor composition, in young ß-III-/- mice underlies early Purkinje cell hyper-excitability and that subsequent loss of GLAST, superimposed on the earlier deficiency of EAAT4, is responsible for Purkinje cell loss and progression of motor deficits. Yet the loss of GLAST appears to be independent of EAAT4 loss, highlighting that other aspects of Purkinje cell dysfunction underpin the pathogenic loss of GLAST. Finally, our results demonstrate that Purkinje cells in the posterior cerebellum of ß-III-/- mice are most susceptible to the combined loss of EAAT4 and GLAST, with degeneration of proximal dendrites, the site of climbing fibre innervation, most pronounced. This highlights the necessity for efficient glutamate clearance from these regions and identifies dysregulation of glutamatergic neurotransmission particularly within the posterior cerebellum as a key mechanism in SCA5 and SPARCA1 pathogenesis.


Subject(s)
Cerebellar Ataxia/metabolism , Disease Models, Animal , Excitatory Amino Acid Transporter 1/metabolism , Excitatory Amino Acid Transporter 4/metabolism , Purkinje Cells/metabolism , Spectrin/metabolism , Spinocerebellar Ataxias/metabolism , Animals , Cerebellar Ataxia/genetics , Cerebellar Ataxia/pathology , Excitatory Amino Acid Transporter 1/physiology , Excitatory Amino Acid Transporter 4/physiology , Female , Male , Mice , Mice, Knockout , Phenotype , Purkinje Cells/pathology , Spectrin/physiology , Spinocerebellar Ataxias/genetics , Spinocerebellar Ataxias/pathology
10.
Brain ; 138(Pt 7): 1817-32, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25981959

ABSTRACT

Cerebral palsy is a sporadic disorder with multiple likely aetiologies, but frequently considered to be caused by birth asphyxia. Genetic investigations are rarely performed in patients with cerebral palsy and there is little proven evidence of genetic causes. As part of a large project investigating children with ataxia, we identified four patients in our cohort with a diagnosis of ataxic cerebral palsy. They were investigated using either targeted next generation sequencing or trio-based exome sequencing and were found to have mutations in three different genes, KCNC3, ITPR1 and SPTBN2. All the mutations were de novo and associated with increased paternal age. The mutations were shown to be pathogenic using a combination of bioinformatics analysis and in vitro model systems. This work is the first to report that the ataxic subtype of cerebral palsy can be caused by de novo dominant point mutations, which explains the sporadic nature of these cases. We conclude that at least some subtypes of cerebral palsy may be caused by de novo genetic mutations and patients with a clinical diagnosis of cerebral palsy should be genetically investigated before causation is ascribed to perinatal asphyxia or other aetiologies.


Subject(s)
Ataxia/genetics , Cerebral Palsy/genetics , Genetic Diseases, Inborn/genetics , Inositol 1,4,5-Trisphosphate Receptors/genetics , Point Mutation , Shaw Potassium Channels/genetics , Spectrin/genetics , Base Sequence , Child , Child, Preschool , DNA Mutational Analysis , High-Throughput Nucleotide Sequencing , Humans , Infant , Infant, Newborn , Male , Patch-Clamp Techniques , Sequence Analysis, DNA
11.
Hum Mol Genet ; 23(14): 3875-82, 2014 Jul 15.
Article in English | MEDLINE | ID: mdl-24603075

ABSTRACT

Beta III spectrin is present throughout the elaborate dendritic tree of cerebellar Purkinje cells and is required for normal neuronal morphology and cell survival. Spinocerebellar ataxia type 5 (SCA5) and spectrin associated autosomal recessive cerebellar ataxia type 1 are human neurodegenerative diseases involving progressive gait ataxia and cerebellar atrophy. Both disorders appear to result from loss of ß-III spectrin function. Further elucidation of ß-III spectrin function is therefore needed to understand disease mechanisms and identify potential therapeutic options. Here, we report that ß-III spectrin is essential for the recruitment and maintenance of ankyrin R at the plasma membrane of Purkinje cell dendrites. Two SCA5-associated mutations of ß-III spectrin both reduce ankyrin R levels at the cell membrane. Moreover, a wild-type ß-III spectrin/ankyrin-R complex increases sodium channel levels and activity in cell culture, whereas mutant ß-III spectrin complexes fail to enhance sodium currents. This suggests impaired ability to form stable complexes between the adaptor protein ankyrin R and its interacting partners in the Purkinje cell dendritic tree is a key mechanism by which mutant forms of ß-III spectrin cause ataxia, initially by Purkinje cell dysfunction and exacerbated by subsequent cell death.


Subject(s)
Ankyrins/metabolism , Purkinje Cells/metabolism , Sodium Channels/physiology , Spectrin/genetics , Spectrin/metabolism , Spinocerebellar Ataxias/genetics , Animals , Cell Membrane/metabolism , Cells, Cultured , HEK293 Cells , Humans , Mice , Mutation , Protein Stability , Purkinje Cells/ultrastructure , Rats , Rats, Sprague-Dawley
12.
Nat Commun ; 4: 2394, 2013.
Article in English | MEDLINE | ID: mdl-23999152

ABSTRACT

Signalling cascades control multiple aspects of presynaptic function. Synaptic vesicle endocytosis was assumed to be exempt from modulation, due to its essential role maintaining synaptic vesicle supply and thus neurotransmission. Here we show that brain-derived neurotrophic factor arrests the rephosphorylation of the endocytosis enzyme dynamin I via an inhibition of glycogen synthase kinase 3. This event results in a selective inhibition of activity-dependent bulk endocytosis during high-intensity firing. Furthermore, the continued presence of brain-derived neurotrophic factor alleviates the rundown of neurotransmission during high activity. Thus, synaptic strength can be modulated by extracellular signalling molecules via a direct inhibition of a synaptic vesicle endocytosis mode.


Subject(s)
Brain-Derived Neurotrophic Factor/metabolism , Dynamin I/metabolism , Glycogen Synthase Kinase 3/antagonists & inhibitors , Synaptic Transmission/physiology , Synaptic Vesicles/metabolism , Animals , Biological Transport , Cells, Cultured , Chromones/pharmacology , Endocytosis/physiology , Enzyme Inhibitors/pharmacology , Female , Glycogen Synthase Kinase 3/metabolism , Hippocampus/cytology , Male , Morpholines/pharmacology , Neurotransmitter Agents/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Phosphoinositide-3 Kinase Inhibitors , Phosphorylation , Rats , Rats, Sprague-Dawley , Signal Transduction
13.
PLoS Genet ; 8(12): e1003074, 2012.
Article in English | MEDLINE | ID: mdl-23236289

ABSTRACT

ß-III spectrin is present in the brain and is known to be important in the function of the cerebellum. Heterozygous mutations in SPTBN2, the gene encoding ß-III spectrin, cause Spinocerebellar Ataxia Type 5 (SCA5), an adult-onset, slowly progressive, autosomal-dominant pure cerebellar ataxia. SCA5 is sometimes known as "Lincoln ataxia," because the largest known family is descended from relatives of the United States President Abraham Lincoln. Using targeted capture and next-generation sequencing, we identified a homozygous stop codon in SPTBN2 in a consanguineous family in which childhood developmental ataxia co-segregates with cognitive impairment. The cognitive impairment could result from mutations in a second gene, but further analysis using whole-genome sequencing combined with SNP array analysis did not reveal any evidence of other mutations. We also examined a mouse knockout of ß-III spectrin in which ataxia and progressive degeneration of cerebellar Purkinje cells has been previously reported and found morphological abnormalities in neurons from prefrontal cortex and deficits in object recognition tasks, consistent with the human cognitive phenotype. These data provide the first evidence that ß-III spectrin plays an important role in cortical brain development and cognition, in addition to its function in the cerebellum; and we conclude that cognitive impairment is an integral part of this novel recessive ataxic syndrome, Spectrin-associated Autosomal Recessive Cerebellar Ataxia type 1 (SPARCA1). In addition, the identification of SPARCA1 and normal heterozygous carriers of the stop codon in SPTBN2 provides insights into the mechanism of molecular dominance in SCA5 and demonstrates that the cell-specific repertoire of spectrin subunits underlies a novel group of disorders, the neuronal spectrinopathies, which includes SCA5, SPARCA1, and a form of West syndrome.


Subject(s)
Cerebellum , Spectrin/genetics , Spinocerebellar Ataxias , Adult , Animals , Cerebellum/growth & development , Cerebellum/pathology , Chromosome Mapping , Cognition Disorders/genetics , Humans , Mice , Mice, Knockout , Mutation , Neurons/metabolism , Neurons/pathology , Purkinje Cells/pathology , Spinocerebellar Ataxias/genetics , Spinocerebellar Ataxias/physiopathology
14.
PLoS Genet ; 8(8): e1002936, 2012.
Article in English | MEDLINE | ID: mdl-22952455

ABSTRACT

Degeneration of synaptic and axonal compartments of neurons is an early event contributing to the pathogenesis of many neurodegenerative diseases, but the underlying molecular mechanisms remain unclear. Here, we demonstrate the effectiveness of a novel "top-down" approach for identifying proteins and functional pathways regulating neurodegeneration in distal compartments of neurons. A series of comparative quantitative proteomic screens on synapse-enriched fractions isolated from the mouse brain following injury identified dynamic perturbations occurring within the proteome during both initiation and onset phases of degeneration. In silico analyses highlighted significant clustering of proteins contributing to functional pathways regulating synaptic transmission and neurite development. Molecular markers of degeneration were conserved in injury and disease, with comparable responses observed in synapse-enriched fractions isolated from mouse models of Huntington's disease (HD) and spinocerebellar ataxia type 5. An initial screen targeting thirteen degeneration-associated proteins using mutant Drosophila lines revealed six potential regulators of synaptic and axonal degeneration in vivo. Mutations in CALB2, ROCK2, DNAJC5/CSP, and HIBCH partially delayed injury-induced neurodegeneration. Conversely, mutations in DNAJC6 and ALDHA1 led to spontaneous degeneration of distal axons and synapses. A more detailed genetic analysis of DNAJC5/CSP mutants confirmed that loss of DNAJC5/CSP was neuroprotective, robustly delaying degeneration in axonal and synaptic compartments. Our study has identified conserved molecular responses occurring within synapse-enriched fractions of the mouse brain during the early stages of neurodegeneration, focused on functional networks modulating synaptic transmission and incorporating molecular chaperones, cytoskeletal modifiers, and calcium-binding proteins. We propose that the proteins and functional pathways identified in the current study represent attractive targets for developing therapeutics aimed at modulating synaptic and axonal stability and neurodegeneration in vivo.


Subject(s)
Brain Injuries , Drosophila , Nerve Degeneration , Synapses , Aldehyde Dehydrogenase/genetics , Aldehyde Dehydrogenase/metabolism , Animals , Axons/metabolism , Axons/pathology , Axons/physiology , Brain Injuries/metabolism , Brain Injuries/pathology , Calbindin 2 , Drosophila/genetics , Drosophila/physiology , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , HSP40 Heat-Shock Proteins/genetics , HSP40 Heat-Shock Proteins/metabolism , Huntington Disease/genetics , Huntington Disease/metabolism , Mice , Molecular Chaperones/genetics , Molecular Chaperones/metabolism , Mutation , Nerve Degeneration/metabolism , Nerve Degeneration/pathology , Proteomics , S100 Calcium Binding Protein G/genetics , S100 Calcium Binding Protein G/metabolism , Spinocerebellar Ataxias/genetics , Spinocerebellar Ataxias/metabolism , Synapses/metabolism , Synapses/pathology , Thiolester Hydrolases/genetics , Thiolester Hydrolases/metabolism , Wallerian Degeneration/metabolism , Wallerian Degeneration/pathology , rho-Associated Kinases/genetics , rho-Associated Kinases/metabolism
15.
J Stroke Cerebrovasc Dis ; 21(2): 143-5, 2012 Feb.
Article in English | MEDLINE | ID: mdl-20851625

ABSTRACT

Here we report a female patient with elderly-onset cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). At age 71, she developed gait disturbance, followed by memory disturbance 1 year later. She had been treated for hypertension and diabetes mellitus for 19 years. There apparently was low penetrance of disease. Magnetic resonance imaging (MRI) findings showed typical features of CADASIL, and the R607C mutation was detected in exon 11 in NOTCH3. This case strongly indicates that CADASIL should be considered when typical findings are observed on MRI even in cases of elderly onset with multiple cerebrovascular risk factors.


Subject(s)
Brain/pathology , CADASIL/diagnosis , Aged , CADASIL/complications , CADASIL/genetics , CADASIL/pathology , DNA Mutational Analysis , Exons , Female , Gait Disorders, Neurologic/etiology , Humans , Magnetic Resonance Imaging , Memory Disorders/etiology , Mutation , Receptor, Notch3 , Receptors, Notch/genetics , Risk Factors
16.
J Neurosci ; 31(46): 16581-90, 2011 Nov 16.
Article in English | MEDLINE | ID: mdl-22090485

ABSTRACT

Mutations in the gene encoding ß-III spectrin give rise to spinocerebellar ataxia type 5, a neurodegenerative disease characterized by progressive thinning of the molecular layer, loss of Purkinje cells and increasing motor deficits. A mouse lacking full-length ß-III spectrin (ß-III⁻/⁻) displays a similar phenotype. In vitro and in vivo analyses of Purkinje cells lacking ß-III spectrin, reveal a critical role for ß-III spectrin in Purkinje cell morphological development. Disruption of the normally well ordered dendritic arborization occurs in Purkinje cells from ß-III⁻/⁻ mice, specifically showing a loss of monoplanar organization, smaller average dendritic diameter and reduced densities of Purkinje cell spines and synapses. Early morphological defects appear to affect distribution of dendritic, but not axonal, proteins. This study confirms that thinning of the molecular layer associated with disease pathogenesis is a consequence of Purkinje cell dendritic degeneration, as Purkinje cells from 8-month-old ß-III⁻/⁻ mice have drastically reduced dendritic volumes, surface areas and total dendritic lengths compared with 5- to 6-week-old ß-III⁻/⁻ mice. These findings highlight a critical role of ß-III spectrin in dendritic biology and are consistent with an early developmental defect in ß-III⁻/⁻ mice, with abnormal Purkinje cell dendritic morphology potentially underlying disease pathogenesis.


Subject(s)
Cerebral Cortex/cytology , Cerebral Cortex/growth & development , Dendrites/ultrastructure , Dendritic Spines/metabolism , Purkinje Cells/cytology , Spectrin/metabolism , Age Factors , Animals , Animals, Newborn , Calbindins , Excitatory Amino Acid Transporter 4/metabolism , Gene Expression Regulation, Developmental/genetics , Glucose Transporter Type 2/metabolism , In Vitro Techniques , Long-Term Synaptic Depression/drug effects , Long-Term Synaptic Depression/genetics , Mice , Mice, Knockout , Microscopy, Electron, Transmission , NAV1.6 Voltage-Gated Sodium Channel , Nerve Tissue Proteins/metabolism , Patch-Clamp Techniques , Phosphate Transport Proteins/metabolism , S100 Calcium Binding Protein G/metabolism , Silver Staining/methods , Sodium Channels/metabolism , Spectrin/deficiency , Vesicular Glutamate Transport Protein 1/metabolism
17.
Intern Med ; 49(22): 2409-14, 2010.
Article in English | MEDLINE | ID: mdl-21088341

ABSTRACT

OBJECTIVE: The frequency of autosomal dominant cerebellar ataxia (ADCA) varies between different regions of Japan. This is the first report on the prevalence of ADCA subtypes in Aomori, Japan. METHODS AND PATIENTS: Sixty-five familial spinocerebellar ataxia (SCA) patients and 15 sporadic SCA patients were genetically examined. For only the SCA2 patients (n = 8), the magnetic resonance imaging (MRI) data were analyzed in detail. RESULTS: Spinocerebellar ataxia (SCA) type 6 was often observed (77.7% of cases), with SCA2 (10.6% of cases) being the next most common form. In contrast, only one of the eighty patients had SCA1. Among the 15 sporadic SCA patients, genetic mutations for SCA2, SCA6, SCA17, and SCA31 were identified, indicating that ADCAs should be considered in sporadic cases of ataxia. Furthermore, in SCA2 cases, brainstem atrophy, pontine midline linear hyperintensity, and atrophy of the frontal lobes were frequently observed using MRI. CONCLUSION: The present data indicate that the prevalence of ADCA in Aomori differs from other prefectures in the Tohoku District. MRI findings are very similar between SCA2 and multiple system atrophy (MSA), and thus care must be taken to prevent the misdiagnosis of sporadic SCA2 as MSA.


Subject(s)
Cerebellar Ataxia/epidemiology , Aged , Cerebellar Ataxia/genetics , Female , Humans , Japan/epidemiology , Male , Middle Aged , Prevalence
18.
Brain Res ; 1361: 140-5, 2010 Nov 18.
Article in English | MEDLINE | ID: mdl-20849835

ABSTRACT

Cystatin C (CC) is a cysteine protease inhibitor abundantly expressed in the central nervous system. Bunina bodies, small eosinophilic intraneuronal inclusions, are stain positive for CC and are the most specific histological hallmark of amyotrophic lateral sclerosis (ALS). In this study, employing a latex turbidimetric immunoassay, levels of CC in cerebrospinal fluid (CSF) were quantified in 130 age-matched individuals with either a neurological disorder [ALS, Alzheimer's disease (AD), Parkinson's disease (PD), tauopathy (TP), multiple system atrophy (MSA), chronic inflammatory demyelinating polyneuropathy (CIDP)] or no known neurological condition (normal control, NC). The CC level in CSF was found to be correlated with the age during the investigation but not the protein concentration. There was no difference in CC levels between NC and ALS or CIDP cases, whereas CC levels were significantly lower in MSA compared with NC. Of the 130 cases, 96 were genotyped, and G/A or A/A polymorphism at +73 within the CST3 gene was found in 28 individuals. The CC level was significantly lower in the combined group of G/A and A/A genotypes compared with G/G. The present data demonstrate that the level of CC in CSF should not be considered as a biomarker of ALS, but there is a correlation between CC levels and the CST3 genotype.


Subject(s)
Cystatin C/cerebrospinal fluid , Nervous System Diseases/cerebrospinal fluid , Nervous System Diseases/genetics , Polymorphism, Single Nucleotide , Aged , Aged, 80 and over , Alanine , Alzheimer Disease/cerebrospinal fluid , Alzheimer Disease/genetics , Amyotrophic Lateral Sclerosis/cerebrospinal fluid , Amyotrophic Lateral Sclerosis/genetics , Biomarkers , Case-Control Studies , Cystatin C/blood , Cystatin C/genetics , Female , Glycine , Humans , Immunoassay/methods , Latex , Male , Middle Aged , Multiple System Atrophy/cerebrospinal fluid , Multiple System Atrophy/genetics , Nephelometry and Turbidimetry/methods , Nervous System Diseases/blood , Parkinson Disease/cerebrospinal fluid , Parkinson Disease/genetics , Polyradiculoneuropathy, Chronic Inflammatory Demyelinating/cerebrospinal fluid , Polyradiculoneuropathy, Chronic Inflammatory Demyelinating/genetics , Tauopathies/cerebrospinal fluid , Tauopathies/genetics
19.
J Neurol Sci ; 296(1-2): 59-63, 2010 Sep 15.
Article in English | MEDLINE | ID: mdl-20621307

ABSTRACT

Here we report a Japanese family with amyotrophic lateral sclerosis (ALS) characterized by very rapid progression, high penetrance and an autosomal dominant mode of inheritance. The phenotype includes atrophy of sternocleidomastoideus muscles, bulbar involvement, weakness of neck muscles and proximal muscle atrophy. These clinical symptoms are reminiscent of myopathy. All patients examined had similar clinical symptoms, age at onset and disease duration. The proband was found to have mutation R521C in the FUS/TLS gene, and was diagnosed as having ALS6. Autopsy material was available from the mother of the proband and FUS-immunoreactive neuronal and glial cytoplasmic inclusions were observed in the anterior horn of the spinal cord. While atrophy and weakness of the sternocleidomastoideus muscle is not emphasized in previous reports, this symptom may be a clinical hallmark of ALS6.


Subject(s)
Amyotrophic Lateral Sclerosis/genetics , RNA-Binding Protein FUS/genetics , Adult , Age of Onset , Amino Acid Substitution , Amyotrophic Lateral Sclerosis/pathology , DNA/genetics , Exons/genetics , Female , Gait Disorders, Neurologic/etiology , Gait Disorders, Neurologic/genetics , Humans , Immunohistochemistry , Inclusion Bodies/pathology , Japan , Male , Muscle Weakness/etiology , Muscle Weakness/pathology , Muscle, Skeletal/pathology , Mutation/genetics , Pedigree , Reverse Transcriptase Polymerase Chain Reaction , Spinal Cord/pathology
20.
Hum Mol Genet ; 19(18): 3634-41, 2010 Sep 15.
Article in English | MEDLINE | ID: mdl-20603325

ABSTRACT

Spinocerebellar ataxia type 5 (SCA5) is an autosomal dominant neurodegenerative disorder caused by mutations in beta-III spectrin. A mouse lacking full-length beta-III spectrin has a phenotype closely mirroring symptoms of SCA5 patients. Here we report the analysis of heterozygous animals, which show no signs of ataxia or cerebellar degeneration up to 2 years of age. This argues against haploinsufficiency as a disease mechanism and points towards human mutations having a dominant-negative effect on wild-type (WT) beta-III spectrin function. Cell culture studies using beta-III spectrin with a mutation associated with SCA5 (L253P) reveal that mutant protein, instead of being found at the cell membrane, appears trapped in the cytoplasm associated with the Golgi apparatus. Furthermore, L253P beta-III spectrin prevents correct localization of WT beta-III spectrin and prevents EAAT4, a protein known to interact with beta-III spectrin, from reaching the plasma membrane. Interaction of beta-III spectrin with Arp1, a subunit of the dynactin-dynein complex, is also lost with the L253P substitution. Despite intracellular accumulation of proteins, this cellular stress does not induce the unfolded protein response, implying the importance of membrane protein loss in disease pathogenesis. Incubation at lower temperature (25 degrees C) rescues L253P beta-III spectrin interaction with Arp1 and normal protein trafficking to the membrane. These data provide evidence for a dominant-negative effect of an SCA5 mutation and show for the first time that trafficking of both beta-III spectrin and EAAT4 from the Golgi is disrupted through failure of the L253P mutation to interact with Arp1.


Subject(s)
Golgi Apparatus/metabolism , Microfilament Proteins/metabolism , Mutation, Missense , Spectrin/genetics , Spectrin/metabolism , Spinocerebellar Ataxias/metabolism , Animals , Disease Models, Animal , Female , Golgi Apparatus/genetics , Humans , Male , Mice , Mice, Knockout , Microfilament Proteins/genetics , Protein Binding , Protein Transport , Spinocerebellar Ataxias/genetics
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