394 research outputs found
Case report of concurrent Fabry disease and amyotrophic lateral sclerosis supports a common pathway of pathogenesis.
C9ORF72 hexanucleotide repeat exerts toxicity in a stable, inducible motor neuronal cell model, which is rescued by partial depletion of Pten.
Amyotrophic lateral sclerosis (ALS) is a devastating and incurable neurodegenerative disease, characterised by progressive failure of the neuromuscular system. A (G4C2)n repeat expansion in C9ORF72 is the most common genetic cause of ALS and frontotemporal dementia (FTD). To date, the balance of evidence indicates that the (G4C2)n repeat causes toxicity and neurodegeneration via a gain-of-toxic function mechanism; either through direct RNA toxicity or through the production of toxic aggregating dipeptide repeat proteins. Here, we have generated a stable and isogenic motor neuronal NSC34 cell model with inducible expression of a (G4C2)102 repeat, to investigate the gain-of-toxic function mechanisms. The expression of the (G4C2)102 repeat produces RNA foci and also undergoes RAN translation. In addition, the expression of the (G4C2)102 repeat shows cellular toxicity. Through comparison of transcriptomic data from the cellular model with laser-captured spinal motor neurons from C9ORF72-ALS cases, we also demonstrate that the PI3K/Akt cell survival signalling pathway is dysregulated in both systems. Furthermore, partial knockdown of Pten rescues the toxicity observed in the NSC34 (G4C2)102 cellular gain-of-toxic function model of C9ORF72-ALS. Our data indicate that PTEN may provide a potential therapeutic target to ameliorate toxic effects of the (G4C2)n repeat
Disrupted glycosylation of lipids and proteins is a cause of neurodegeneration
Glycosyltransferases represent a large family of enzymes that catalyse the biosynthesis of oligosaccharides, polysaccharides, and glycoconjugates. A number of studies have implicated glycosyltransferases in the pathogenesis of neurodegenerative diseases but differentiating cause from effect has been difficult. We have recently discovered that mutations proximal to the substrate binding site of glycosyltransferase 8 domain containing 1 (GLT8D1) are associated with familial amyotrophic lateral sclerosis (ALS). We demonstrated that ALS-associated mutations reduce activity of the enzyme suggesting a loss-of-function mechanism that is an attractive therapeutic target. Our work is the first evidence that isolated dysfunction of a glycosyltransferase is sufficient to cause a neurodegenerative disease, but connection between neurodegeneration and genetic variation within glycosyltransferases is not new. Previous studies have identified associations between mutations in UGT8 and sporadic ALS, and between ST6GAL1 mutations and conversion of mild cognitive impairment into clinical Alzheimer’s disease. In this review we consider potential mechanisms connecting glycosyltransferase dysfunction to neurodegeneration. The most prominent candidates are ganglioside synthesis and impaired addition of O-linked β-N-acetylglucosamine (O-GlcNAc) groups to proteins important for axonal and synaptic function. Special consideration is given to examples where genetic mutations within glycosyltransferases are associated with neurodegeneration in recognition of the fact that these changes are likely to be upstream causes present from birth
Late-onset Tay-Sachs disease
We discuss the assessment and differential diagnoses of a young adult Hungarian man with a 1-year history of a progressive and symmetric amyotrophic lateral sclerosis-like syndrome, along with irregular action tremor and stimulus-sensitive myoclonus of the arms. MR scan of the brain showed isolated cerebellar atrophy and formal neuropsychometric testing identified significant subclinical deficits in attention, processing speed and memory. We suspected a form of GM2 gangliosidosis, and white cell enzyme analysis showed markedly reduced enzymatic activity of β-hexosaminidase A. Genetic testing subsequently revealed two heterozygous pathogenic mutations in the HEXA gene (c.1499delT p.(Leu500fs) and c.805G>A p.(Gly269Ser)), confirming the very rare diagnosis of adult-onset Tay-Sachs disease
Does data count? The politics of complaint, data and police accountability
Advances in technology have expanded the possibilities of state surveillance, but they have also expanded opportunities for citizens to collect data on the state.2 At present, cell phone videos, WhatsApp monitoring groups and crowdsourced mapping of real-time events are producing a raft of new data to add to older forms of civic data gathering. In the wake of global mobilisation around issues of police wrongdoing and accountability, it is important to reflect on the impact that data may have on the pursuit of justice, redress, and transformation.3While not discounting the rich policing literature that exists on police accountability and change, we have opted in this article to draw on the work of Sara Ahmed, who explores complaints in the United Kingdom higher education sector.4 Her work, we argue, can help us understand why counting people does not always make them count. In other words, Ahmed shows how the effectiveness of data in securing redress and reform is often curtailed by the same patterns of oppression and stigma that facilitate police wrongdoing in the first place. In this article, we explain Ahmed’s concept of a ‘complaint biography’ and her exposition of complaint work more broadly. We also apply her ideas to incidents of complaints against the police, and interrogate the role and importance of physical violence in this regard
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NetDiff – Bayesian model selection for differential gene regulatory network inference
Differential networks allow us to better understand the changes in cellular processes that are exhibited in conditions of interest, identifying variations in gene regulation or protein interaction between, for example, cases and controls, or in response to external stimuli. Here we present a novel methodology for the inference of differential gene regulatory networks from gene expression microarray data. Specifically we apply a Bayesian model selection approach to compare models of conserved and varying network structure, and use Gaussian graphical models to represent the network structures. We apply a variational inference approach to the learning of Gaussian graphical models of gene regulatory networks, that enables us to perform Bayesian model selection that is significantly more computationally efficient than Markov Chain Monte Carlo approaches. Our method is demonstrated to be more robust than independent analysis of data from multiple conditions when applied to synthetic network data, generating fewer false positive predictions of differential edges. We demonstrate the utility of our approach on real world gene expression microarray data by applying it to existing data from amyotrophic lateral sclerosis cases with and without mutations in C9orf72, and controls, where we are able to identify differential network interactions for further investigation
“Maybe we should take the legal ways”: Citizen engagement with lower state courts in post‐war northern Uganda
Lower state courts are the focus of both international and national access to justice policies and programs but remain understudied in Uganda. Drawing on 3 years of ethnographically informed research on citizen engagement with a busy magistrates' court in post-war northern Uganda, we show the diverse reasons why citizens appeal to the rule-of-law in places where state authority is contested. In a context of limited statehood, against a backdrop of high-levels of corruption and inefficiency in the judicial system, people turn to lower state courts for normative, pragmatic, and tactical reasons that are not well captured by conventional measures of procedural justice. Our findings extend theory on citizen-authority relations in a global context, shedding light on contextual meanings of legitimacy, trust, and corruption in places where lower state courts are deeply problematic sites for achieving justice
Physical activity as an exogenous risk factor for amyotrophic lateral sclerosis: a review of the evidence
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and fatal neurodegenerative disorder. The only established epidemiological risk factors for ALS are male sex and increasing age. The role of physical activity has been debated as an environmental risk factor. Over the last decade multiple studies have attempted to delineate the architecture of ALS. These have not yet established definite risk factors, often due to low-powered studies, lack of focus on at-risk genotypes and sub-optimal methodology.
We have conducted a review of all the studies published between 2009 and December 2021. The free text search terms were [(motor neuron disease) OR (MND) OR (Amyotrophic Lateral Sclerosis) OR (ALS)] AND [(Exercise) or (Physical Activity) or (PA) or (sport)]. We identified common themes, for example soccer, head injury and the physiological mechanisms that differ in ALS patients. We have analysed the relevant, available studies (n = 93), highlighting the underlying reasons for any reported discrepancies.
Overall, we have found that the more highly powered studies using validated exposure methodologies, linked strenuous, anaerobic physical activity as a risk factor for ALS. Future large-scale studies focusing on specific at-risk genotypes and physical activity should be conducted to confirm this finding. This will strengthen the evidence already surrounding strenuous physical activity as an environmental risk factor for ALS and allow advice to be given to at-risk family members. Increasing our understanding of the genetic–environmental interactions in the pathophysiology of ALS will allow for the possibility of developing preventative therapeutic approaches
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