Ice bucket challenge bears fruit for amyotrophic lateral sclerosis

In 2014, the ‘ice bucket challenge’ raised over $140 million worldwide for research into amyotrophic lateral sclerosis (ALS). This unprecedented boost to research funding is now beginning to deliver significant advances in our understanding of the pathogenesis of this devastating disease, and all the studies in this month’s journal club were, at least in part, funded by charitable organisations that benefited from these monies. The first paper we discuss reports the results of the largest genetic study of ALS to date, with discovery of three new genes associated with ALS by utilising novel whole-genome sequencing technology. Importantly, the study also illuminates the genetic architecture of ALS, which in turn is likely to inform design of future genetic studies and suggests opportunities for clinical research to establish genotype–phenotype correlations. However, as genetic studies of rapidly increasing power reveal increasing numbers of risk variants and mutations, the next substantial challenge is to understand how such variants cause disease. The second and third papers discussed this month report on attempts to understand how two leading ALS risk variants cause disease and may provide exciting avenues for the development of novel therapeutic agents. The association of the C9orf72 repeat expansion with ALS, reviewed in journal club in 2012 and 2015, is now well documented and Kramer et al. report notable progress in translating our understanding into novel therapeutic targets. Similarly, Ito et al. report that mutations in the established ALS risk gene optineurin may function by sensitising cells to a form of regulated cell death, which could again be targeted for therapeutic intervention

Advances in the genetics of stroke risk and recovery

Cerebrovascular disease (CVD) is widely considered a heterogeneous clinical syndrome rather than a single disorder. A large number of modifiable and non-modifiable risk factors have been associated with CVD, but even after accounting for these, there remains a large proportion of unexplained individual risk. Although genetic risk has commonly been considered non-modifiable, it is now better understood how environmental influences can modify gene expression as a result of epigenetic phenomena. Genome-Wide Association Studies (GWAS) have identified some genetic risk loci for stroke, many of which are common to CVD in general. It is hoped that a more comprehensive understanding of genetic risk in differing populations will have the potential to improve our understanding of disease pathogenesis and to identify novel therapeutic mechanisms. This in turn could be used to quantify risk of stroke at a young age, integrate with advice on lifestyle choices, and develop opportunities to target preventive treatments

Clinical outcomes of escalation vs early intensive disease-modifying therapy in patients with multiple sclerosis

IMPORTANCE Uncertainty remains about how aggressively to treat early multiple sclerosis. High-efficacy disease-modifying therapies (DMTs) are often reserved for individuals expressing poor prognostic features at baseline. OBJECTIVE To analyze long-term outcomes in a population-based cohort according to initial treatment strategy. DESIGN, SETTING AND PARTICIPANTS In this cohort study, data were derived from January 1998 to December 2016, and analysis was performed in January 2017. From a total of 720 patients prescribed a DMT, 592 (82%) were included in analysis. Reasons for exclusion were first treated elsewhere or privately (n = 39), clinical trial participant (n = 25), and insufficient clinical data (n = 45). EXPOSURES Patients were classified according to first-line treatment strategy: high-efficacy (early intensive treatment [EIT]) or moderate-efficacy DMT (escalation [ESC]). MAIN OUTCOMES AND MEASURES Primary outcome was 5-year change in Expanded Disability Status Scale score. Secondary outcome was time to sustained accumulation of disability (SAD). Models were adjusted for sex, age at treatment, year of starting DMT, and escalation to high-efficacy treatment in the ESC group. RESULTS Mean (SD) age of 592 patients at symptom onset was 27.0 (9.4) years. Mean (SD) 5-year change in Expanded Disability Status Scale score was lower in the EIT group than the ESC group (0.3 [1.5] vs 1.2 [1.5]); this remained significant after adjustment for relevant covariates (β = −0.85; 95% CI, −1.38 to −0.32; P = .002). Median (95% CI) time to SAD was 6.0 (3.17-9.16) years for EIT and 3.14 (2.77-4.00) years for ESC (P = .05). For those within the ESC group who escalated to high-efficacy DMT as second-line treatment, median (95% CI) time to SAD was 3.3 years (1.8-5.6; compared with EIT group log-rank test P = .08). After adjustment for relevant covariates, there was no difference in hazard of SAD between the groups. However, 60% of those who escalated to high-efficacy DMTs were observed to develop SAD while still receiving initial moderate-efficacy treatment before escalation. CONCLUSIONS AND RELEVANCE In a real-life setting, long-term outcomes were more favorable following early intensive therapy vs first-line moderate-efficacy DMT. Contemporary surveillance strategies and escalation protocols may be insufficiently responsive. This finding is particularly relevant as patients in real-world practice are typically selected for an EIT approach to therapy on the basis of clinical and radiological features predictive of a poor outcome. These data support the need for a prospective randomized clinical trial

CSF-resident CD4+ T-cells display a distinct gene expression profile with relevance to immune surveillance and multiple sclerosis

The CNS has traditionally been considered an immune privileged site, but is now understood to have a system of immune surveillance, predominantly involving CD4+ T-cells. Identifying functional differences between CNS and blood CD4+ T-cells, therefore, have relevance to CNS immune surveillance as well as to neurological conditions, such as multiple sclerosis, in which CD4+ T-cells play a central role. Here, CD4+ T-cells were purified from CSF and blood from 21 patients with newly diagnosed treatment-naïve multiple sclerosis and 20 individuals with non-inflammatory disorders using fluorescence-activated cell sorting, and their transcriptomes were profiled by RNA sequencing. Paired comparisons between CD4+ T-cells from CSF and blood identified 5156 differentially expressed genes in controls and 4263 differentially expressed in multiple sclerosis patients at false discovery rate <5%. Differential expression analysis of CD4+ T-cells collected from the CSF highlighted genes involved in migration, activation, cholesterol biosynthesis and signalling, including those with known relevance to multiple sclerosis pathogenesis and treatment. Expression of markers of CD4+ T-cell subtypes suggested an increased proportion of Th1 and Th17 cells in CSF. Gene ontology terms significant only in multiple sclerosis were predominantly those involved in cellular proliferation. A two-way comparison of CSF versus blood CD4+ T-cells in multiple sclerosis compared with non-inflammatory disorder controls identified four significant genes at false discovery rate <5% (CYP51A1, LRRD1, YES1 and PASK), further implicating cholesterol biosynthesis and migration mechanisms. Analysis of CSF CD4+ T-cells in an extended cohort of multiple sclerosis cases (total N = 41) compared with non-inflammatory disorder controls (total N = 38) identified 140 differentially expressed genes at false discovery rate < 5%, many of which have known relevance to multiple sclerosis, including XBP1, BHLHE40, CD40LG, DPP4 and ITGB1. This study provides the largest transcriptomic analysis of purified cell subpopulations in CSF to date and has relevance for the understanding of CNS immune surveillance, as well as multiple sclerosis pathogenesis and treatment discovery

Modelling disease progression of Multiple Sclerosis in a South Wales cohort

Objectives: To model multiple sclerosis (MS) disease progression and compare disease trajectories by sex, age of onset, and year of diagnosis. Study Design and settings: Longitudinal EDSS scores (20,854 observations) were collected for 1787 relapse-onset MS patients at MS clinics in South Wales and modelled using a multilevel model (MLM). The MLM adjusted for baseline covariates (sex, age of onset, year of diagnosis, and disease modifying treatments (DMTs)), and included interactions between baseline covariates and time variables. Results: The optimal model was truncated at 30 years after disease onset and excluded EDSS recorded within 3 months of relapse. As expected, older age of onset was associated with faster disease progression at 15 years (effect size (ES): 0.75; CI: 0.63, 0.86; P: 2011) progressed more slowly than those diagnosed historically (<2006); (ES: -0.46; CI: -0.75, -0.16; P: 0.006) and (ES: -0.95; CI: -1.20, -0.70; P: <0.001), respectively. Conclusion: We present a novel model of MS outcomes, accounting for the nonlinear trajectory of MS and effects of baseline covariates, validating well-known risk factors (sex and age of onset) associated with disease progression. Also, patients diagnosed more recently progressed more slowly than those diagnosed historically

Multiple sclerosis: long-term outcomes in ethnic minorities. analysis of a UK population-based registry

Background and purpose Multiple sclerosis (MS) is most frequent in Caucasian populations. However, studies of MS in other ethnic groups may offer unique insights into genetic and environmental influences on the disease, and data on long-term outcomes in these patients is limited. In this work clinical features and time to disability milestones were investigated in ethnic minority (EM) patients with MS in a UK population and comparisons were made to a Caucasian cohort from the same region. Methods In all, 1949 MS patients (1866 Caucasian, 83 EM) were identified from a regional disease registry. Cox proportional hazards regression was used to analyse the time to Expanded Disability Status Scale (EDSS) 3.0, 4.0 and 6.0. Results Ethnic minority patients were younger at disease onset (28.6 years vs. 32.8 years, P = 0.001), and primary progressive MS was less common (EM 4.8%, Caucasian 11.6%, P = 0.03). After correction for clinical variables, ethnicity was associated with time to EDSS 3.0 [EM: hazard ratio (HR) 1.75, P < 0.0001] and 4.0 (HR 1.46, P = 0.03), but not 6.0 (HR 1.5, P = 0.05). Conclusions Ethnic minority patients reach early levels of fixed disability more rapidly than Caucasian patients, but this effect diminishes at later stages of the disease. This has implications for clinical management of these patients

Gene expression regulation in immune cell dysfunction in multiple sclerosis

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS). Genome-wide association studies in MS have identified over 200 genetic risk variants, but most are non-coding. Non-coding genetic variants are known to control gene expression in specific cells and contexts, but the tissues whose functions are altered by the MS genetic risk variants are largely unknown. CSF CD4+ T-cells play a key role in CNS immune surveillance, but gene expression analysis of CNS CD4+ T-cells has been limited. Building on the clinical research infrastructure in Cardiff a method was developed that obtained RNA from low numbers of CD4+ T-cells from cerebrospinal fluid (CSF) from 111 of 135 consenting patients. Gene expression profiles of CSF CD4+ T-cells were compared with those of blood CD4+ T-cells from the same patients using RNA-seq. Thousands of differentially expressed genes were identified in controls as well as MS, highlighting many functional differences. Expression quantitative trait locus analysis revealed 93 genes with expression associated with a genetic variant (eGenes). 29 eGenes may be specific to CSF CD4+ T-cells. Summary data-based Mendelian randomisation revealed no genes reaching genome-wide significance for association with MS, but seven genes with nominal significance. This work has developed a technically challenging pipeline to further our understanding of CNS immune surveillance by CD4+ T-cells in health and in MS. Building on this study, future work could provide a more complete understanding of the genetic aetiology of MS and other neurological disorders by 1) exploring novel sensitive data analysis methods to identify eGenes and prioritise potentially causal genes, 2) expanding analysis to other cell types and activation states (freshly collected or derived from induced pluripotent stem cells), 3) performing multiplex analysis combining gene expression with chromatin accessibility studies and proteomics, 4) testing for association between gene expression and longitudinal clinical data