UFMylation is a ubiquitin-like protein modification of Ubiquitin Fold Modifier 1 (UFM1) applied to substrate proteins and regulates several cellular processes such as protein quality control. Here, we describe the development of an antibody-based enrichment approach to immunoprecipitate remnant UFMylated peptides and identification by mass spectrometry. We used this approach to identify >200 UFMylation sites from various mouse tissues, revealing extensive modification in skeletal muscle. In vivo knockdown of the E2 ligase, UFC1, followed by enrichment and analysis of remnant UFMylated peptides quantified concomitant down-regulation and validation of a subset of modification sites, particularly myosin UFMylation. Furthermore, we show that UFMylation is increased in skeletal muscle biopsies from people living with amyotrophic lateral sclerosis (plwALS). Quantification of UFMylation sites in these biopsies with multiplexed isotopic labeling reveal prominent increases in myosin UFMylation. Our data suggest that in vivo UFMylation is more complex than previously thought.

Objective: Fatigue is a common symptom in amyotrophic lateral sclerosis (ALS). Little is known about factors that contribute to fatigue, and whether levels of fatigue change throughout disease course. We aimed to determine associations between self-reported perceived fatigue and metabolic and clinical features of ALS, and perceived fatigue over the course of disease. Methods: This prospective study was conducted between July 2017 and March 2024. Baseline measures of self-reported perceived fatigue, metabolic rate, and clinical measures of disease were assessed in 117 participants with clinically definite or probable ALS. For comparison, fatigue and metabolic rate were collected from 107 control participants. Perceived fatigue was determined using the Fatigue Severity Scale (FSS). Metabolic rate was assessed using indirect calorimetry. Functional capacity and clinical progression were assessed using the ALS Functional Rating Scale-Revised (ALSFRS-R). Results: Baseline levels of perceived fatigue were greater in people living with ALS (plwALS) when compared to controls (5.44 vs. 2.55; p < 0.01). Perceived fatigue was higher in plwALS with lower ALSFRS-R scores and was not associated with measures of metabolism. For most plwALS, perceived fatigue remained high as functional capacity worsened. Conclusion: Our findings confirm higher prevalence of perceived fatigue in plwALS, with persistently high FSS scores reported by most patients during follow-up. High levels of fatigue were not associated with hypermetabolism, suggesting that metabolic rate is unlikely to be a primary contributor. Results highlight a need for further research to identify factors that contribute to fatigue in ALS, and options for improved fatigue management.

BACKGROUND:Motor neuron disease (MND) leads to progressive functional decline, making reliable measures of disease progression critical for patient care and clinical trials. Current clinical outcome measures lack the ability to continuously and objectively track functional decline in daily life of patients with MND. This study assessed and validated wrist-worn accelerometry outcome measures for continuous monitoring in MND, with the potential to refine clinical trial outcomes. METHODS:This longitudinal study included 95 patients with MND who wore an ActiGraph GT9X Link device on their non-dominant wrist for 8 days, with follow-up every 3-4 months. Accelerometer data were processed using ActiLife and GGIR. Joint models were used to simultaneously investigate the longitudinal change in ALS Functional Rating Scale-Revised (ALSFRS-R) scores and accelerometer-derived outcomes alongside their relationship with overall survival. Sample size estimates for clinical trials were generated using both accelerometer- and ALSFRS-R-based outcomes, and principal component analysis (PCA) explored outcome relationships. FINDINGS:Accelerometer outcomes showed a slower rate of decline (-0.03 to -0.07 SD/month) compared to ALSFRS-R (-0.10 SD/month) and had stronger correlations with ALSFRS-R motor subdomains (partial r: 0.60-0.73). PCA revealed that longitudinal measures of accelerometry were distinct from the ALSFRS-R, highlighting the complementary nature of these measures. Peak 6-min activity predicted smaller clinical trial sample sizes for studies over 12 months. Accelerometer-derived outcomes were not significantly associated with survival. INTERPRETATION:Wrist-worn accelerometry offers a practical solution for continuous monitoring in MND, complementing ALSFRS-R. Measures of peak performance, and specifically peak 6-min activity shows promise, potentially reducing sample sizes and improving disease tracking over longer duration studies. Further refinement and validation are needed to adopt actigraphy measures as clinical assessment outcomes. FUNDING:This study was supported by Wesley Medical Research (2016-32), the Honda Foundation, Motor Neurone Disease Research Australia, and FightMND. CJH received a Higher Degree Research Scholarship from UQ. STN received support from the Scott Sullivan Fellowship (MND and Me Foundation/RBWH Foundation), a FightMND Mid-Career Fellowship, and the AIBN.

Motor Neuron Disease (MND) is associated with significant non-motor symptoms, including the loss of appetite. Loss of appetite has emerged as a dominant feature of the disease that may contribute to negative energy balance, faster disease progression and earlier death. We examined the prevalence and impact of appetite loss and analysed neural correlates of visual food stimuli with prandial status and appetite in people living with MND (plwMND). 157 plwMND and 120 non-neurodegenerative controls (NND Controls) were assessed for anthropometric, metabolic, appetite and clinical measures. Of these, 35 plwMND and 23 NND Controls underwent further functional MRI assessment of fasting and postprandial responses to visual food cues. plwMND presented with reduced appetite (p<0.001), with loss of appetite being more prevalent in plwMND than NND Controls (OR=2.59 (95% CI=1.46–4.61)). Loss of appetite was not associated with hypermetabolism however was associated with fat mass loss (p<0.05). Imaging assessment revealed no overall difference in response between plwMND and NND Controls when viewing non-food and food images. In contrast, we found no prandial response in the temporal pole of plwMND compared to NND Controls, and decreased activity in the cerebellum relative to appetite in plwMND. Loss of appetite, not hypermetabolism, contributes to negative energy balance in MND. Alterations in the temporal pole and cerebellum could contribute to altered appetite responses in some plwMND - brain regions not widely considered in appetite control - providing additional evidence to support widespread involvement of non-motor areas in the disease.

This dataset provides the first annotated, openly available MRI-based imaging dataset for investigations of tongue musculature, including multi-contrast and multi-site MRI data from non-disease participants. The present dataset includes 47 participants collated from three studies: BeLong (four participants; T2-weighted images), EATT4MND (19 participants; T2-weighted images), and BMC (24 participants; T1-weighted images). We provide manually corrected segmentations of five key tongue muscles: the superior longitudinal, combined transverse/vertical, genioglossus, and inferior longitudinal muscles. Other phenotypic measures, including age, sex, weight, height, and tongue muscle volume, are also available for use. This dataset will benefit researchers across domains interested in the structure and function of the tongue in health and disease. For instance, researchers can use this data to train new machine learning models for tongue segmentation, which can be leveraged for segmentation and tracking of different tongue muscles engaged in speech formation in health and disease. Altogether, this dataset provides the means to the scientific community for investigation of the intricate tongue musculature and its role in physiological processes and speech production.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with highly heterogeneous clinical presentations. Among the non-motor features increasingly recognised as clinically relevant is the dysregulation of energy balance, with weight loss-particularly due to fat mass loss-emerging as a significant modifier of disease risk, progression, and survival. In this context, the hypothalamus-a key regulator of homeostatic and metabolic processes-has gained attention for its potential role in ALS pathophysiology. This Review synthesises emerging evidence of hypothalamic involvement in ALS, including neuronal loss, proteinopathy, and volume loss observed through histological and neuroimaging studies. We critically examine current imaging approaches and their technical limitations and explore neuroendocrine dysfunction across the hypothalamic-pituitary axes. Collectively, these findings suggest that hypothalamic dysfunction may contribute to clinically relevant metabolic, sleep, behavioural, and cognitive changes in ALS, adding to our understanding of ALS as a multisystem disease. Continued investigation of the hypothalamus may reveal novel biomarkers, inform risk stratification, and identify therapeutic opportunities to address disease heterogeneity and improve clinical outcomes.

BackgroundMotor neuron disease (MND) is a progressive and incurable neurodegenerative disease. The Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) is the primary clinical tool for assessing disease severity and progression in MND. However, despite its widespread use, it does not adequately capture the extent of physical function decline. There is an urgent need for sensitive measures of disease progression that can be used to robustly evaluate new treatments. Measures of physical function derived from digital devices are beginning to be used to assess disease progression. There is value in establishing a consensus approach to standardizing the use of such devices. ObjectiveWe aimed to explore how digital devices are being used to quantify free-living physical behavior in MND. We evaluated the feasibility and assessed the implications for monitoring physical behavior for future clinical trials and clinical practice. MethodsSystematic searches of 4 databases were performed in October 2023 and June 2024. Peer-reviewed English-language articles (including preprints) that examined how people living with MND used digital devices to assess their free-living physical behavior were included. Study reporting quality was assessed using a 22-item checklist (maximum possible score=44 points). ResultsIn total, 12 articles met the inclusion criteria for data extraction. All studies were longitudinal and observational in design, but data collection, analysis, and reporting protocols varied. Quality assessment scores ranged between 19 and 40 points. Sample sizes ranged between 10 and 376 people living with MND at baseline, declining over the course of the study. Most studies used an accelerometer device worn on the wrist, chest, hip, or ankle. Participants were typically asked to continuously wear devices for 1 to 8 days at 1- to 4-month intervals, with studies running for 12 weeks to 24 months. Some studies asked participants to wear the device continuously for the full duration. Studies derived traditional end points focusing on duration, intensity, and frequency of physical activity or nontraditional end points focusing on features of an individual’s movement patterns. The correlation coefficients (r) between physical behavior end points and ALSFRS-R ranged from 0.31 to 0.78. Greater monitoring frequencies and improved end point sensitivity were shown to provide smaller sample size requirements and shorter durations for hypothetical clinical trials. People living with MND found using devices acceptable and reported a low burden. Adherence assessed in 8 (67%) studies was good, ranging from approximately 86% to 96%, with differences evident between wear locations. The perspectives of other end users and implications on clinical practice were not explored. ConclusionsRemote monitoring of free-living physical behavior in MND is in its infancy but has the potential to quantify physical function. It is essential to develop a consensus statement, working toward agreed and standardized methods for data collection, analysis, and reporting.

Metabolic imbalance is associated with amyotrophic lateral sclerosis progression. Impaired glucose oxidation and increased reliance on fatty acid oxidation contribute to reduced metabolic flexibility and faster disease progression in amyotrophic lateral sclerosis. We sought to evaluate the safety and tolerability, and explore the pharmacodynamic response of trimetazidine, a partial fatty acid oxidation inhibitor, on oxidative stress markers and energy expenditure in amyotrophic lateral sclerosis. The study was conducted between June 29, 2021 and May 24, 2023. People living with amyotrophic lateral sclerosis, recruited in Australia and the Netherlands, received open-label oral trimetazidine for 12 weeks after an initial 4-week lead-in period. The primary outcome measures were safety and tolerability, as well as the change from baseline in oxidative stress markers malondialdehyde (MDA) and 8-hydroxy-2 '-deoxyguanosine (8-OHdG). Secondary outcome measures were change from baseline in energy expenditure, amyotrophic lateral sclerosis functional rating scale-revised, and slow vital capacity (SVC). Linear mixed effects were used to estimate the mean difference in MDA and 8-OHdG between the on- and off-treatment periods. This trial is registered under ClinicalTrial.gov National Clinical Trial (NCT) number NCT04788745 and European Union Drug Regulating Authorities Clinical Trials (EudraCT) number 2020-005018-17. Twenty-one participants received trimetazidine; 19 (90%) completed the treatment period. Trimetazidine was well tolerated; there were 57 adverse events reported, of which 7 (11%) were deemed potentially drug-related, including hot flushes (2), nausea (2), paraesthesia (2) and fatigue (1). MDA was numerically lower during treatment [-0.29 uM; 95% confidence interval (CI) -0.90 to 0.33, P = 0.36]; 8-OHdG was significantly lower during treatment (-0.12 nM; 95% CI -0.23 to -0.01, P = 0.0245). The decrease in oxidative stress markers was accompanied by a reduction in resting energy expenditure (95 kcal, 95% CI 36.8-154, P = 0.0014). The absence of a placebo group prevented the interpretation of the clinical parameters. Oral trimetazidine was safe and well tolerated among patients with amyotrophic lateral sclerosis. This, combined with the significant reduction in markers of oxidative stress and resting energy expenditure, warrants a larger double-blind placebo-controlled efficacy study. van Eijk and Steyn et al. report that oral trimetazidine is safe and well tolerated in amyotrophic lateral sclerosis patients, significantly reducing oxidative stress markers and resting energy expenditure. These findings highlight the potential of trimetazidine as a therapeutic intervention for amyotrophic lateral sclerosis, warranting larger, placebo-controlled studies to confirm efficacy.

The dataset investigates the neural correlates of appetite in people living with motor neuron disease (plwMND) compared to non-neurodegenerative disease controls. Thirty-six plwMND and twenty-three controls underwent two fMRI sessions: one in a fasted state and one postprandial. Participants viewed visual stimuli of non-food items, low-calorie foods, and high-calorie foods in a randomised block design. Imaging data included T1w, T2w, and task-based and resting-state fMRI scans, and measures are complemented by subjective appetite questionnaires and anthropometric measures. This dataset is unique for its inclusion of functional imaging across prandial states, offering insights into the neural mechanisms of appetite regulation in patients with MND. Researchers can explore various aspects of the data, including the functional responses to food stimuli and their associations with clinical and appetite measures. The data, deposited in OpenNeuro, follows the Brain Imaging Data Structure (BIDS) standard, ensuring compatibility and reproducibility for future research. This comprehensive dataset provides a resource for studying the central mechanisms of appetite regulation in MND.

Background: Motor neuron disease (MND) profoundly impacts mobility, yet gait-specific dysfunctions due to MND remain poorly understood. Methods: We characterized lower-limb gait alterations in people living with MND (plwMND) using advanced biomechanical tools. Nine plwMND and nine non-neurodegenerative disease controls walked on an instrumented treadmill at self-selected speeds. Ground reaction forces and joint motions were measured to model lower-limb kinetics, kinematics, and energetics. Results: PlwMND had reduced forward propulsive (p < 0.001) and braking (p = 0.002) ground reaction forces. Ankle range of motion was 10.0 ± 3.1° lower (p = 0.035) with peak positive ankle moment and power 33% and 72% lower, respectively (both: p < 0.001), in plwMND compared to controls. Conclusions: These lower-limb impairments highlight the ankle as an early and critical locus of dysfunction, with distal weakness driving compensatory proximal strategies, increasing walking inefficiency and fatigue. Integrating biomechanical and clinical data offers new insights into gait disruption in MND, supporting the development of targeted, personalized interventions to maintain independent mobility.

This work addresses the challenge of reliably measuring the muscles of the human tongue, which are difficult to quantify due to complex interwoven muscle types. We introduce a new semi-automated method, enabled by a manually curated dataset of MRI scans to accurately measure five key tongue muscles, combining AI-assisted, atlas-based, and manual segmentation approaches. The method was tested and validated in a dataset of 178 scans and included segmentation validation (n = 103) and clinical application (n = 132) in individuals with motor neuron disease. We show that people with speech and swallowing deficits tend to have smaller muscle volumes and present a normalisation strategy that removes confounding demographic factors, enabling broader application to large MRI datasets. As the tongue is generally covered in neuroimaging protocols, our multi-contrast pipeline will allow for the post-hoc analysis of a vast number of datasets. We expect this work to enable the investigation of tongue muscle morphology as a marker in a wide range of diseases that implicate tongue function, including neurodegenerative diseases and pathological speech disorders.

Cell-free DNA (cfDNA) is increasingly recognized as a promising biomarker candidate for disease monitoring. However, its utility in neurodegenerative diseases, like amyotrophic lateral sclerosis (ALS), remains underexplored. Existing biomarker discovery approaches are tailored to a specific disease context or are too expensive to be clinically practical. Here, we address these challenges through a new approach combining advances in molecular and computational technologies. First, we develop statistical tools to select tissue-informative DNA methylation sites relevant to a disease process of interest. We then employ a capture protocol to select these sites and perform targeted methylation sequencing. Multi-modal information about the DNA methylation patterns are then utilized in machine learning algorithms trained to predict disease status and disease progression. We applied our method to two independent cohorts of ALS patients and controls (n=192). Overall, we found that the targeted sites accurately predicted ALS status and replicated between cohorts. Additionally, we identified epigenetic features associated with ALS phenotypes, including disease severity. These findings highlight the potential of cfDNA as a non-invasive biomarker for ALS.

Metabolic dysfunction-associated steatohepatitis (MASH) is the most prevalent cause of liver disease worldwide, with a single approved therapeutic. Previous research has shown that interleukin-22 (IL-22) can suppress β-cell stress, reduce local islet inflammation, restore appropriate insulin production, reverse hyperglycemia, and ameliorate insulin resistance in preclinical models of diabetes. In clinical trials long-acting forms of IL-22 have led to increased proliferation in the skin and intestine, where the IL-22RA1 receptor is highly expressed. To maximise beneficial effects whilst reducing the risk of epithelial proliferation and cancer, we designed short-acting IL-22-bispecific biologic drugs that successfully targeted the liver and pancreas. Here we show 10-fold lower doses of these bispecific biologics exceed the beneficial effects of native IL-22 in multiple preclinical models of MASH, without off-target effects. Treatment restores glycemic control, markedly reduces hepatic steatosis, inflammation, and fibrogenesis. These short-acting IL-22-bispecific targeted biologics are a promising new therapeutic approach for MASH.

BACKGROUND AND OBJECTIVES:Altered metabolism is observed in amyotrophic lateral sclerosis (ALS). However, without a standardized methodology to define metabolic changes, our understanding of factors contributing to and the clinical significance of altered metabolism in ALS is limited. METHODS:We aimed to determine how geographic variation in metabolic rates influences estimates and accuracy of predicted resting energy expenditure (REE) in patients with ALS and controls, while validating the effectiveness of cohort-specific approaches in predicting altered metabolic rate in ALS. Participants from 3 geographically distinct sites across Australia, China, and the Netherlands underwent REE assessments, and we considered 22 unique equations for estimating REE. Analyses evaluated equation performance and the influence of demographics on metabolic status. Comparisons were made using standardized and local reference values to identify metabolic alterations. RESULTS:606 participants were included from Australia (patients with ALS: 140, controls: 154), the Netherlands (patients with ALS: 79, controls: 37) and China (patients with ALS: 67, controls: 129). Measured REE was variable across geographic cohorts, with fat-free mass contributing to this variation across all patients (p = 0.002 to p < 0.001). Of the 22 predication equations assessed, the Sabounchi Structure 4 (S4) equation performed relatively well across all control cohorts. Use of prediction thresholds generated using data from Australian controls generally increased the prevalence of hypermetabolism in Chinese (55%, [43%-67%]) and Dutch (44%, [33%-55%]) cases when compared with Australian cases (30%, [22%-38%]). Adjustment of prediction thresholds to consider geographically distinct characteristics from matched control cohorts resulted in a decrease in the proportion of hypermetabolic cases in Chinese and Dutch cohorts (25%-31% vs 55% and 20%-34% vs 43%-44%, respectively), and increased prevalence of hypometabolism in Dutch cases with ALS (1% to 8%-10%). DISCUSSION:The identification of hypermetabolism in ALS is influenced by the formulae and demographic-specific prediction thresholds used for defining alterations in metabolic rate. A consensus approach is needed for identification of metabolic changes in ALS and will facilitate improved understanding of the cause and clinical significance of this in ALS.

In humans, there are two arylamine Nacetyltransferase genes that encode functional enzymes (NAT1 and NAT2) as well as one pseudogene, all of which are located together on chromosome 8. Although they were first identified by their role in the acetylation of drugs and other xenobiotics, recent studies have shown strong associations for both enzymes in a variety of diseases, including cancer, cardiovascular disease, and diabetes. There is growing evidence that this association may be causal. Consistently, NAT1 and NAT2 are shown to be required for healthy mitochondria. This review discusses the current literature on the role of both NAT1 and NAT2 in mitochondrial bioenergetics. It will attempt to relate our understanding of the evolution of the two genes with biologic function and then present evidence that several major metabolic diseases are influenced by NAT1 and NAT2. Finally, it will discuss current and future approaches to inhibit or enhance NAT1 and NAT2 activity/expression using small -molecule drugs. Significance Statement--The arylamine N-acetyltransferases (NATs) NAT1 and NAT2 share common features in their associations with mitochondrial bioenergetics. This review discusses mitochondrial function as it relates to health and disease, and the importance of NAT in mitochondrial function and dysfunction. It also compares NAT1 and NAT2 to highlight their functional similarities and differences. Both NAT1 and NAT2 are potential drug targets for diseases where mitochondrial dysfunction is a hallmark of onset and progression.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. Clinical heterogeneity and complex genetics pose challenges to understanding disease mechanisms and producing effective cures. To model clinical heterogeneity, we generated human induced pluripotent stem cells (iPSCs) from two sporadic ALS patients (sporadic ALS and sporadic ALS with frontotemporal dementia), two familial ALS patients (familial SOD1 mutation positive and familial C9orf72 repeat expansion positive), and four age- and sex-matched healthy controls. These iPSCs can be used to generate 2D and 3D in vitro models of ALS to investigate mechanisms of disease and screen for therapeutics.

Arginine methylation is a protein posttranslational modification important for the development of skeletal muscle mass and function. Despite this, our understanding of the regulation of arginine methylation under settings of health and disease remains largely undefined. Here, we investigated the regulation of arginine methylation in skeletal muscles in response to exercise and hypertrophic growth, and in diseases involving metabolic dysfunction and atrophy. We report a limited regulation of arginine methylation under physiological settings that promote muscle health, such as during growth and acute exercise, nor in disease models of insulin resistance. In contrast, we saw a significant remodeling of asymmetric dimethylation in models of atrophy characterized by the loss of innervation, including in muscle biopsies from patients with myotrophic lateral sclerosis (ALS). Mass spectrometry-based quantification of the proteome and asymmetric arginine dimethylome of skeletal muscle from individuals with ALS revealed the largest compendium of protein changes with the identification of 793 regulated proteins, and novel site-specific changes in asymmetric dimethyl arginine (aDMA) of key sarcomeric and cytoskeletal proteins. Finally, we show that in vivo overexpression of PRMT1 and aDMA resulted in increased fatigue resistance and functional recovery in mice. Our study provides evidence for asymmetric dimethylation as a regulator of muscle pathophysiology and presents a valuable proteomics resource and rationale for numerous methylated and nonmethylated proteins, including PRMT1, to be pursued for therapeutic development in ALS.

BACKGROUND AND PURPOSE:Loss of appetite contributes to weight loss and faster disease progression in amyotrophic lateral sclerosis (ALS). Impairment of appetite control in ALS may include altered production or action of orexigenic (i.e., ghrelin) and anorexigenic (i.e., liver-expressed antimicrobial peptide 2 [LEAP2] and leptin) hormones. We aimed to determine if postprandial circulating ghrelin levels, LEAP2 levels, LEAP2:ghrelin molar ratio and leptin levels differ in ALS patients compared to non-neurodegenerative disease controls, and whether they are associated with disease progression and body composition. METHODS:In this prospective natural history study, we assessed postprandial plasma levels of ghrelin, LEAP2 and leptin in patients with ALS (cases; n = 46) and controls (controls; n = 43). For cases, measures were compared to changes in body weight, body composition and clinical outcomes. RESULTS:Postprandial ghrelin level was decreased by 52% in cases compared to controls (p = 0.013). LEAP2:ghrelin molar ratio was increased by 249% (p = 0.009), suggesting greater ghrelin resistance. Patients with lower LEAP2:ghrelin tended to have better functional capacity at assessment, as inferred by the ALS Functional Rating Scale-Revised (τ = -0.179, p = 0.086). Furthermore, ghrelin and LEAP2:ghrelin molar ratio correlated with diagnostic delay (ghrelin, τ = 0.223, p = 0.029; LEAP2:ghrelin, τ = -0.213, p = 0.037). Baseline ghrelin level, LEAP2 level, LEAP2:ghrelin ratio and leptin level were, however, not predictive of change in functional capacity during follow-up. Also, patients with higher postprandial ghrelin levels (hazard ratio [HR] 1.375, p = 0.048), and lower LEAP2:ghelin ratios (HR 0.828, p = 0.051) had an increased risk of earlier death. CONCLUSIONS:Reduced postprandial ghrelin levels, coupled with increased LEAP2:ghrelin molar ratios, suggests a loss of ghrelin action in patients with ALS. Given ghrelin's actions on appetite, metabolism and neuroprotection, reduced ghrelin and greater ghrelin resistance could contribute to impaired capacity to tolerate the physiological impact of disease. Comprehensive studies are needed to explain how ghrelin and LEAP2 contribute to body weight regulation and disease progression in ALS.

Actigraphy has been proposed as a measure for tracking functional decline and disease progression in patients with Motor Neuron Disease (MND). There is, however, little evidence to show that wrist-based actigraphy measures correlate with functional decline, and no consensus on how best to implement actigraphy. We report on the use of wrist actigraphy to show decreased activity in patients compared to controls, and compared the utility of wrist- and hip-based actigraphy for assessing functional decline in patients with MND. In this multi-cohort, multi-centre, natural history study, wrist- and hip-based actigraphy were assessed in 139 patients with MND (wrist, n = 97; hip, n = 42) and 56 non-neurological control participants (wrist, n = 56). For patients with MND, longitudinal measures were contrasted with clinical outcomes commonly used to define functional decline. Patients with MND have reduced wrist-based actigraphy scores when compared to controls (median differences: prop. active = − 0.053 [− 0.075, − 0.026], variation axis 1 = − 0.073 [− 0.112, − 0.021]). When comparing wrist- and hip-based measures, hip-based accelerometery had stronger correlations with disease progression (prop. active: τ = 0.20 vs 0.12; variation axis 1: τ = 0.33 vs 0.23), whereas baseline wrist-based accelerometery was better related with future decline in fine-motor function (τ = 0.14–0.23 vs 0.06–0.16). Actigraphy outcomes measured from the wrist are more variable than from the hip and present differing sensitivity to specific functional outcomes. Outcomes and analysis should be carefully constructed to maximise benefit, should wrist-worn devices be used for at-home monitoring of disease progression in patients with MND.

Background Amyotrophic lateral sclerosis (ALS), the most predominant form of Motor Neuron Disease (MND), is a progressive and fatal neurodegenerative condition that spreads throughout the neuromotor system by afflicting upper and lower motor neurons. Lower motor neurons project from the central nervous system and innervate muscle fibres at motor endplates, which degrade over the course of the disease leading to muscle weakness. The direction of neurodegeration from or to the point of neuromuscular junctions and the role of muscle itself in pathogenesis has continued to be a topic of debate in ALS research. Methods To assess the variation in gene expression between affected and nonaffected muscle tissue that might lead to this local degeneration of motor units, we generated RNA-seq skeletal muscle transcriptomes from 28 MND cases and 18 healthy controls and conducted differential expression analyses on gene-level counts, as well as an isoform switching analysis on isoform-level counts. Results We identified 52 differentially-expressed genes (Benjamini-Hochberg-adjusted p < 0.05) within this comparison, including 38 protein coding, 9 long non-coding RNA, and 5 pseudogenes. Of protein-coding genes, 31 were upregulated in cases including with notable genes including the collagenic COL25A1 ( p = 3.1 × 10−10), SAA1 which is released in response to tissue injury ( p = 3.6 × 10−5) as well as others of the SAA family, and the actin-encoding ACTC1 ( p = 2.3 × 10−5). Additionally, we identified 17 genes which exhibited a functional isoform switch with likely functional consequences between cases and controls. Conclusions Our analyses provide evidence of increased tissue generation in MND cases, which likely serve to compensate for the degeneration of motor units and skeletal muscle. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This research was supported through funding from the Scott Sullivan MND Research Fellowship to S.T.N. (2015-2020; MND and Me Foundation and RBWH Foundation), FightMND Mid-Career Fellowship (to S.T.N.), MNDRA Charcot Grant (GIA 1701 to S.T.N. and F.J.S.), the National Health and Medical Research Council Australia (1101085 to S.T.N. and F.J.S., 1113400 & 1173790 to N.R.W.) and the Australian Research Council (Future Fellowship 200100837 to A.F.M.). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: All work performed in this study was approved by the Royal Brisbane and Women's Hospital and University of Queensland human research ethics committees. All participants provided written informed consent. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The data that support the findings of this study are available on request from the corresponding author. The raw transcript data are not publicly available due to ethical restrictions; however, gene and transcript counts have been made available. The datasets generated during and/or analysed during the current study are available in the University of Queensland data collection repository. * ALS-FRS-R : Revised Amyotrophic Lateral Sclerosis Functional Rating Scale ALS : Amyotrophic lateral sclerosis EM : Expectation maximalization GIF : Surrogate variable analysis lncRNA : Long non-coding RNA MND : Motor neurone disease NMJ : Neuromuscular junction ORF : Open reading frame PC : Protein coding PCA : Principal component analysis PP : Processed pseudogene RIN : RNA integrity number TUP : Transcribed unprocessed pseudogene. UP : Unprocessed pseudogene