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Background Increased catabolism has recently been recognized as a clinical manifestation of amyotrophic lateral sclerosis (ALS). The hypothalamic systems have been shown to be involved in the metabolic dysfunction in ALS, but the exact extent of hypothalamic circuit alterations in ALS is yet to be determined. Here we explored the integrity of large-scale cortico-hypothalamic circuits involved in energy homeostasis in murine models and in ALS patients. Methods The rAAV2-based large-scale projection mapping and image analysis pipeline based on Wholebrain and Ilastik software suites were used to identify and quantify projections from the forebrain to the lateral hypothalamus in the SOD1(G93A) ALS mouse model (hypermetabolic) and the FusΔNLS ALS mouse model (normo-metabolic). 3 T diffusion tensor imaging (DTI)-magnetic resonance imaging (MRI) was performed on 83 ALS and 65 control cases to investigate cortical projections to the lateral hypothalamus (LHA) in ALS. Results Symptomatic SOD1(G93A) mice displayed an expansion of projections from agranular insula, ventrolateral orbitofrontal and secondary motor cortex to the LHA. These findings were reproduced in an independent cohort by using a different analytic approach. In contrast, in the FusΔNLS ALS mouse model hypothalamic inputs from insula and orbitofrontal cortex were maintained while the projections from motor cortex were lost. The DTI-MRI data confirmed the disruption of the orbitofrontal-hypothalamic tract in ALS patients. Conclusion This study provides converging murine and human data demonstrating the selective structural disruption of hypothalamic inputs in ALS as a promising factor contributing to the origin of the hypermetabolic phenotype.

The genetic basis of amyotrophic lateral sclerosis (ALS) is still incompletely understood. Using two independent genetic strategies, we show here that a large part of ALS heritability lies in genes expressed in inhibitory and excitatory neurons, especially at splicing sites regulated by a defined set of RNA binding proteins including TDP-43 and FUS. We conducted a transcriptome wide association study (TWAS) and identified 59 loci associated with ALS, including 14 previously identified genes, some of them not previously reaching significance in genome wide association studies. Among the 45 novel genes, several genes are involved in pathways known to be affected in ALS such as mitochondrial metabolism (including ATP5H, ATP5D, BCS1L), proteostasis (including COPS7A, G2E3, TMEM175, USP35) or gene expression and RNA metabolism (including ARID1B, ATXN3, PTBP2, TAF10). Interestingly, decreased expression of NUP50, a constrained gene encoding a nuclear pore basket protein, was associated with ALS in TWAS (Zscore = −4, FDR = 0.034). 11 potentially pathogenic variants (CADD score > 20) in 23 patients were identified in the NUP50 gene, most of them in the region of the protein mediating interaction with Importin alpha, and including 2 frameshift mutations. In cells from two patients carrying NUP50 variants, we showed decreased levels of NUP50 protein. Importantly, knocking down Nup50 led to increased neuronal death associated with p62 and nucleoporin inclusions in cultured neurons, and motor defects in Drosophila and zebrafish models. In all, our study identifies alterations in splicing in neurons as a critical pathogenic process in ALS, uncovers several new loci potentially contributing to ALS missing heritability, and provides genetic evidence linking nuclear pore defects to ALS.

International audience; Background: The pathophysiology of the hypothalamic involvement in Parkinson's disease (PD) is not well understood. The objective of this study was the quantification of hypothalamic volumes in vivo in PD.Methods: High-resolution T1 -weighted magnetic resonance imaging (MRI) data from 232 individuals with PD and 130 healthy non-PD individuals were used for quantification of the hypothalamic volumes.Results: The hypothalamus in PD was not atrophied, as indicated by volumetric analyses in the prospectively collected subcohort (30 PD, V = 921 ± 78 mm3 vs 30 non-PD, V = 917 ± 67 mm3 ; P = 0.850) and validated in a large cohort (202 PD, V = 925 ± 88 mm3 vs 100 non-PD, V = 932 ± 114 mm3 ; P = 0.602).Conclusions: Hypothalamic involvement in PD as shown by a large body of histopathological evidence does not appear to be detectable by MRI-based volumetric quantification. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Large polyglutamine expansions in Ataxin-2 (ATXN2) cause multi-system nervous atrophy in Spinocerebellar Ataxia type 2 (SCA2). Intermediate size expansions carry a risk for selective motor neuron degeneration, known as Amyotrophic Lateral Sclerosis (ALS). Conversely, the depletion of ATXN2 prevents disease progression in ALS. Although ATXN2 interacts directly with RNA, and in ALS pathogenesis there is a crucial role of RNA toxicity, the affected functional pathways remain ill defined. Here, we examined an authentic SCA2 mouse model withAtxn2-CAG100-KnockIn for a first definition of molecular mechanisms in spinal cord pathology. Neurophysiology of lower limbs detected sensory neuropathy rather than motor denervation. Triple immunofluorescence demonstrated cytosolic ATXN2 aggregates sequestrating TDP43 and TIA1 from the nucleus. In immunoblots, this was accompanied by elevated CASP3, RIPK1 and PQBP1 abundance. RT-qPCR showed increase ofGrn,Tlr7andRnaset2mRNA versusEif5a2,Dcp2, Uhmk1andKif5adecrease. These SCA2 findings overlap well with known ALS features. Similar to other ataxias and dystonias, decreased mRNA levels forUnc80,Tacr1,Gnal,Ano3,Kcna2,Elovl5andCdr1contrasted withGpnmbincrease. Preterminal stage tissue showed strongly activated microglia containing ATXN2 aggregates, with parallel astrogliosis. Global transcriptome profiles from stages of incipient motor deficit versus preterminal age identified molecules with progressive downregulation, where a cluster of cholesterol biosynthesis enzymes includingDhcr24,Msmo1,Idi1andHmgcs1was prominent. Gas chromatography demonstrated a massive loss of crucial cholesterol precursor metabolites. Overall, the ATXN2 protein aggregation process affects diverse subcellular compartments, in particular stress granules, endoplasmic reticulum and receptor tyrosine kinase signaling. These findings identify new targets and potential biomarkers for neuroprotective therapies.

Mutations disrupting the nuclear localization of the RNA-binding protein FUS characterize a subset of amyotrophic lateral sclerosis patients (ALS-FUS). FUS regulates nuclear RNAs, but its role at the synapse is poorly understood. Using super-resolution imaging we determined that the localization of FUS within synapses occurs predominantly near the vesicle reserve pool of presynaptic sites. Using CLIP-seq on synaptoneurosomes, we identified synaptic FUS RNA targets, encoding proteins associated with synapse organization and plasticity. Significant increase of synaptic FUS during early disease in a mouse model of ALS was accompanied by alterations in density and size of GABAergic synapses. mRNAs abnormally accumulated at the synapses of 6-month-old ALS-FUS mice were enriched for FUS targets and correlated with those depicting increased short-term mRNA stability via binding primarily on multiple exonic sites. Our study indicates that synaptic FUS accumulation in early disease leads to synaptic impairment, potentially representing an initial trigger of neurodegeneration., Mutations in the RNA-binding protein FUS contribute to ALS. Here the authors use CLIP-seq on synaptoneurosomes to identify proteins associated with synapse organization and plasticity that are differentially regulated in a knock-in ALS mouse model.

Purpose of review Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease targeting upper and lower motor neurons, inexorably leading to an early death. Defects in energy metabolism have been associated with ALS, including weight loss, increased energy expenditure, decreased body fat mass and increased use of lipid nutrients at the expense of carbohydrates. We review here recent findings on impaired energy metabolism in ALS, and its clinical importance. Recent findings Hypothalamic atrophy, as well as alterations in hypothalamic peptides controlling energy metabolism, have been associated with metabolic derangements. Recent studies showed that mutations causing familial ALS impact various metabolic pathways, in particular mitochondrial function, and lipid and carbohydrate metabolism, which could underlie these metabolic defects in patients. Importantly, slowing weight loss, through high caloric diets, is a promising therapeutic strategy, and early clinical trials indicated that it might improve survival in at least a subset of patients. More research is needed to improve these therapeutic strategies, define pharmacological options, and refine the population of ALS patients that would benefit from these approaches. Summary Dysfunctional energy homeostasis is a major feature of ALS clinical picture and emerges as a potential therapeutic target.

Amyotrophic lateral sclerosis (ALS) is the major adult onset motor neuron disease characterized by progressive muscle paralysis and spasticity leading ultimately to death of the patient within 2 to 5 years after onset. ALS is typically associated with degeneration of upper and lower motor neurons. Degeneration of brainstem serotonin neurons has recently been demonstrated in both ALS patients and mouse models, and was found responsible for the development of spasticity, once thought to be caused by the sole impairment of the corticospinal tract. Consistent with involvement of central serotonin pathways, the 5-HT2B receptor was found upregulated in microglia of ALS mice. Its deletion worsened disease outcome in a mouse model and led to microglial degeneration. In ALS patients, a polymorphism in HTR2B gene was associated with survival in patients as well as microglial degeneration. As a whole, these studies suggest that the clinical phenotype of ALS patients is partially caused by the degeneration of serotonergic neurons and that microglial 5-HT2B receptor is critical for survival of this cell type in ALS spinal cord.

Amyotrophic lateral sclerosis (ALS) is a devastating progressive neurodegenerative disorder. While initially pathophysiology was thought to be restricted to motor deficits, it is increasingly recognized that patients develop prominent changes in weight and eating behavior that result from and mediate the underlying neurodegenerative process. These changes include alterations in metabolism, lipid levels, and insulin resistance. Emerging research suggests that these alterations may be mediated through changes in the hypothalamic function, with atrophy of the hypothalamus shown in both ALS patients and also presymptomatic genetic at-risk patients. This chapter reviews the evidence for hypothalamic involvement in ALS, including melanocortin pathways and potential treatment targets.

Mutations in FUS, an RNA-binding protein involved in multiple steps of RNA metabolism, are associated with the most severe forms of amyotrophic lateral sclerosis (ALS). Accumulation of cytoplasmic FUS is likely to be a major culprit in the toxicity of FUS mutations. Thus, preventing cytoplasmic mislocalization of the FUS protein may represent a valuable therapeutic strategy. FUS binds to its own pre-mRNA creating an autoregulatory loop efficiently buffering FUS excess through multiple proposed mechanisms including retention of introns 6 and/or 7. Here, we introduced a wild-type FUS gene allele, retaining all intronic sequences, in mice whose heterozygous or homozygous expression of a cytoplasmically retained FUS protein (FusΔNLS) was previously shown to provoke ALS-like disease or postnatal lethality, respectively. Wild-type FUS completely rescued the early lethality caused by the two FusΔNLS alleles, and improved age-dependent motor deficit and reduced lifespan associated with the heterozygous expression of FusΔNLS. Mechanistically, wild-type FUS decreased the load of cytoplasmic FUS, increased exon 7 skipping and retention of introns 6 and 7 in the endogenous mouse Fus mRNA, leading to decreased expression of the mutant mRNA. Thus, the wild-type FUS allele activates the homeostatic autoregulatory loop, maintaining constant FUS levels and decreasing the mutant protein in the cytoplasm. These results provide proof of concept that an autoregulatory competent wild-type FUS expression could protect against this devastating, currently intractable, neurodegenerative disease.

Increased catabolism is a new clinical manifestation of Amyotrophic Lateral Sclerosis. A dysfunction of lateral hypothalamus may drive hypermetabolism in ALS; however, Its causes and anatomical substrates are unknown. We hypothesize that disruption cortico-hypothalamic circuits may impair energy homeostasis in ALS. We used rAAV2 for large-scale projection mapping and image analysis pipeline based on Wholebrain and Ilastik to quantify projections from the forebrain to the latera hypothalamus of the SOD1(G93A) ALS mouse model as well as of the FusΔNLS ALS mouse model. Expanded projections from agranular Insula, ventrolateral orbitofrontal and secondary motor cortex to lateral hypothalamus were found in two independent cohorts of the hypermetabolic SOD1(G93A) ALS model. The non-hypermetabolic FusΔNLS ALS mouse model display a loss of projections from motor cortex but no change in projections from insula and orbitofronal cortex. 3T DTI-MRI data on 83 ALS patients and 65 controls confirmed the disruption of the orbitofrontal-hypothalamic tract in ALS patients. Converging murine and human data demonstrate the selective disruption of hypothalamic inputs in ALS as a factor contributing to the origin of hypermetabolism.Significance statementWe provide a circuit perspective of the recently identified and medically relevant hyper-metabolic phenotype of Amyotrophic Lateral Sclerosis. We demonstrate the selective involvement of orbitofrontal, insular and motor cortex projections to hypothalamus in murine ALS models and in human patients. The enhanced pipeline for large-scale registration, segmentation projections mapping, the identification of new circuits target of neurodegeneration, and the relevance of these circuits in metabolic disturbances make this work relevant not only for the investigation of ALS but also for other neurodegenerative disease as well as for all conditions characterized by systemic energy imbalances.

Recent publications showed that circulating neurofilaments (Nfs) may be used as a diagnostic biomarker distinguishing amyotrophic lateral sclerosis (ALS) from ALS mimics with high sensitivity and specificity.1–3 Furthermore, it has been shown that patients with higher Nf levels show faster disease progression1 and shorter survival.2 3 Nf levels remain rather stable during the course of disease.2 Current literature suggests that the diagnostic value of neurofilament light chains (NfL) and phosphorylated neurofilament heavy chains in cerebrospinal fluid is about equal, whereas in blood NfL seems to be superior.4 In this study, we investigated the effect of a high-caloric fatty diet (HCFD) on NfL serum levels, using blood samples collected during the LIPCAL-ALS (efficacy, safety and tolerability of high lipid and caloriesupplementation in amyotrophic lateral sclerosis) study, a randomised, double-blind, parallel-group, placebo-controlled, multicentre trial, which investigated the therapeutic effect of HCFD in ALS.5 In LIPCAL-ALS, 201 patients (80 women, 121 men, age 62.4±10.8) were randomly assigned (1:1) to receive either HCFD (405 kcal/day, 100% fat) or placebo in addition to riluzole (100 mg/day) for 18 months. Although the primary outcome overall survival was negative in the whole study population (p=0.44), the post hoc analysis revealed a significantly longer survival for fast-progressing patients (ie, patients with an Amyotrophic Lateral Sclerosis Functional Rating Scale Revised (ALSFRS-R) slope >median between disease onset and baseline) in the HCFD group compared with placebo.5 To further corroborate our hypothesis of a disease-modifying effect of HCFD, we analysed NfL serum levels from LIPCAL-ALS participants. At each on-site visit during LIPCAL-ALS (6-month intervals), patients were asked if they were willing to provide an additional serum sample for NfL analysis on a voluntary basis. Serum NfL concentrations were measured with the single molecule array (Simoa) platform provided by Quanterix (Lexington, Massachusetts, USA) with single measurements …

FUS is a primarily nuclear RNA-binding protein with important roles in RNA processing and transport. FUS mutations disrupting its nuclear localization characterize a subset of amyotrophic lateral sclerosis (ALS-FUS) patients, through an unidentified pathological mechanism. FUS regulates nuclear RNAs, but its role at the synapse is poorly understood. Here, we used super-resolution imaging to determine the physiological localization of extranuclear, neuronal FUS and found it predominantly near the vesicle reserve pool of presynaptic sites. Using CLIP-seq on synaptoneurosome preparations, we identified synaptic RNA targets of FUS that are associated with synapse organization and plasticity. Synaptic FUS was significantly increased in a knock-in mouse model of ALS-FUS, at presymptomatic stages, accompanied by alterations in density and size of GABAergic synapses. RNA-seq of synaptoneurosomes highlighted age-dependent dysregulation of glutamatergic and GABAergic synapses. Our study indicates that FUS accumulation at the synapse in early stages of ALS-FUS results in synaptic impairment, potentially representing an initial trigger of neurodegeneration.

We investigated the associations of serum concentration of insulin-like growth factor 1 (IGF1) with risk and prognosis of ALS in the ALS registry (October 2010–June 2014, median follow-up 67.6 months) in a case-control and cohort study, respectively. Serum samples were measured for IGF-1. Information on covariates was collected by standardized questionnaire. We applied conditional logistic regression to appraise the risk and Cox proportional hazards models to appraise the prognostic value of IGF-1. Data of 294 ALS patients (mean age 65.4 (SD 11.0) years, 60.2% men) and 504 controls were included in the case-control study. Median serum IGF-1 concentrations were slightly higher in ALS cases than in controls (101 vs. 99.5 ng/ml). IGF-1 concentrations were not associated with ALS risk in the fully adjusted model (top vs. bottom quartile: OR 1.16; 95%-CI 0.73–1.84, p for trend = 0.44). Among 293 ALS cases (mean age 65.5 (SD 10.5) years, 56.8% men) 243 died during follow-up. We found a statistically significant inverse association between continuous IGF-1 concentrations and survival (p = 0.01). Very high values IGF-1 were associated with a better prognosis of ALS suggesting that functions related to IGF-1 could be involved in survival.

Chemogenetic motoneuron excitation and astrocyte GPCR-Gi signaling restore blood–spinal cord barrier, disrupted in four ALS mouse models, revealing its role in disease progression but not initiation., Blood–spinal cord barrier (BSCB) disruption is thought to contribute to motoneuron (MN) loss in amyotrophic lateral sclerosis (ALS). It is currently unclear whether impairment of the BSCB is the cause or consequence of MN dysfunction and whether its restoration may be directly beneficial. We revealed that SOD1G93A, FUSΔNLS, TDP43G298S, and Tbk1+/− ALS mouse models commonly shared alterations in the BSCB, unrelated to motoneuron loss. We exploit PSAM/PSEM chemogenetics in SOD1G93A mice to demonstrate that the BSCB is rescued by increased MN firing, whereas inactivation worsens it. Moreover, we use DREADD chemogenetics, alone or in multiplexed form, to show that activation of Gi signaling in astrocytes restores BSCB integrity, independently of MN firing, with no effect on MN disease markers and dissociating them from BSCB disruption. We show that astrocytic levels of the BSCB stabilizers Wnt7a and Wnt5a are decreased in SOD1G93A mice and strongly enhanced by Gi signaling, although further decreased by MN inactivation. Thus, we demonstrate that BSCB impairment follows MN dysfunction in ALS pathogenesis but can be reversed by Gi-induced expression of astrocytic Wnt5a/7a.

Iron accumulation has been observed in mouse models and in both sporadic and familial forms of amyotrophic lateral sclerosis (ALS). Iron chelation could reduce iron accumulation and the related excess of oxidative stress in the motor pathways. However, classical iron chelation would induce systemic iron depletion. We assess the safety and efficacy of conservative iron chelation (i.e., chelation with low risk of iron depletion) in a murine preclinical model and pilot clinical trial. In Sod1G86R mice, deferiprone increased the mean life span compared with placebo. The safety was good, without anemia after 12 months of deferiprone in the 23 ALS patients enrolled in the clinical trial. The decreases in the ALS Functional Rating Scale and the body mass index were significantly smaller for the first 3 months of deferiprone treatment (30 mg/kg/day) than for the first treatment-free period. Iron levels in the cervical spinal cord, medulla oblongata, and motor cortex (according to magnetic resonance imaging), as well as cerebrospinal fluid levels of oxidative stress and neurofilament light chains were lower after deferiprone treatment. Our observation leads to the hypothesis that moderate iron chelation regimen that avoids changes in systemic iron levels may constitute a novel therapeutic modality of neuroprotection for ALS. Antioxid. Redox Signal. 29, 742-748.

International audience; Background: Rasagiline, a monoamine oxidase B inhibitor with neuroprotective potential in Parkinson's disease, has shown a disease-modifying effect in the SOD1-Gly93Ala low-expressing mouse model of amyotrophic lateral sclerosis, both alone and in combination with riluzole. We sought to test whether or not rasagiline 1 mg/day can prolong survival in patients with amyotrophic lateral sclerosis also receiving riluzole.Methods: Patients with possible, probable, or definite amyotrophic lateral sclerosis were enrolled to our randomised, placebo-controlled, parallel-group, double-blind, phase 2 trial from 15 German network for motor neuron diseases (MND-NET) centres (university hospitals or clinics). Eligible patients were aged at least 18 years, had onset of progressive weakness within the 36 months before the study, had disease duration of more than 6 months and less than 3 years, and had a best-sitting slow vital capacity of at least 50%. After a 4-week screening period, eligible patients were randomly assigned (1:1) to receive either rasagiline (1 mg/day) or placebo in addition to riluzole (100 mg/day), after stratification for site of onset (bulbar or spinal) and study centre. Patients and all personnel assessing outcome parameters were masked to treatment allocation. Patients were followed up 2, 6, 12, and 18 months after randomisation. The primary endpoint was survival time, defined as the time to death or time to study cutoff date (ie, the last patient's last visit plus 14 days). Analyses of primary outcome and safety measures were done in all patients who received at least one dose of trial treatment (intention-to-treat population). The trial is registered with ClinicalTrials.gov, number NCT01879241.Findings: Between July 2, 2013, and Nov 11, 2014, 273 patients were screened for eligibility, and 252 patients were randomly assigned to receive rasagiline (n=127) or placebo (n=125). 126 patients taking rasagiline and 125 taking placebo were included in the intention-to-treat analysis. For the primary outcome, the survival probability at the end of the study was 0·43 (95% CI 0·25-0·59) in the rasagiline group (n=126) and 0·53 (0·43-0·62) in the placebo group (n=125). The estimated effect size (hazard ratio) was 0·91 (one-sided 97·5% CI -infinity to 1·34; p=0·31). Rasagiline was well tolerated, and most adverse events were due to amyotrophic lateral sclerosis disease progression rather than treatment; the most frequent of these were dysphagia (32 [25%] taking rasagiline vs 24 [19%] taking placebo) and respiratory failure (25 [20%] vs 31 [25%]). Frequency of adverse events were comparable between both groups.Interpretation: Rasagiline was safe in patients with amyotrophic lateral sclerosis. There was no difference between groups in the primary outcome of survival, although post-hoc analysis suggested that rasagiline might modify disease progression in patients with an initial slope of Amyotrophic Lateral Sclerosis Functional Rating Scale Revised greater than 0·5 points per month at baseline. This should be confirmed in another clinical trial.Funding: Teva Pharmaceutical Industries.

International audience; Traumatic brain injury (TBI) has been proposed as a risk factor for neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). To determine whether TBI might trigger or exacerbate ALS-relevant pathology, we delivered a mild stab-wound injury to the motor cortex of three different ALS mouse models expressing mutations in SOD1, TDP-43 or FUS and scrutinized the effects on the formation of phospho-TDP-43 (pTDP-43) cytoplasmic granules. Stab-injury induced the formation of cytoplasmic TDP-43 granules in wt animals, peaking at 3dpi; a much larger response was seen in mutant TDP-43 mice, whose response peaked at 7dpi. The pTDP-43 granules did not colocalize with the stress markers TIAR-1 and FUS but colocalized with FMRP (35%) and with p62 (65%), suggesting their involvement in transport granules and their clearance by autophagy. A similar, albeit smaller effect, was seen in mutant FUS mice. In the SOD1G93A mouse model, neither increase in pTDP-43 granules nor in SOD1 aggregates were detected. In all cases, pTDP-43 granules were cleared and the number of pTDP-43-positive neurons returned to baseline by 40dpi. Neither injury-related neuronal loss nor motor performance or survival was significantly different in transgenic mice receiving injury vs sham mice. Thus, trauma can trigger ALS-related TDP-43 pathology, the extent of which is modulated by ALS-related mutations. However, the pathological findings prove reversible and do not affect disease progression and neuronal vulnerability.

Objective: Spasticity occurs in a wide range of neurological diseases, including neurodegenerative diseases, after trauma or after stroke and is characterized by increased reflexes leading to muscle hypertonia. Spasticity is a painful symptom and can severely restrict everyday life, but might also participate in maintaining a low level of motor function in severely impaired patients. Constitutive activity of the serotonin receptors 5-HT2B/C is required for the development of spasticity after spinal cord injury or during amyotrophic lateral sclerosis (ALS). We sought here to provide direct evidence for a role of brainstem serotonin neurons in spasticity. Methods: SOD1(G37R) mice expressing a conditional allele of an ALS-linked SOD1 mutation were crossed to Tph2-CRE mice expressing CRE in serotonergic neurons. Measurement of long lasting reflex using EMG, behavioural follow up and histological techniques were used to characterize spasticity and motor phenotype. Results: Deleting mutant SOD1 expression selectively in brainstem serotonin neurons was sufficient to rescue loss of TPH2 immunoreactivity and largely preserve serotonin innervation of motor neurons in the spinal cord. Furthermore, this abrogated constitutive activity of 5-HT2B/C receptors and abolished spasticity in end-stage mice. Consistent with spasticity mitigating motor symptoms, selective deletion worsened motor function and accelerated the onset of paralysis. Interpretation: Degeneration of serotonin neurons is necessary to trigger spasticity through the 5-HT2B/C receptor. The wide range of drugs targeting the serotonergic system could be useful to treat spasticity in neurological diseases. This article is protected by copyright. All rights reserved.

International audience; Objective: Our objective was to study the hypothalamic volume in a cohort of patients with amyotrophic lateral sclerosis (ALS) including symptomatic and presymptomatic ALS mutation carriers.Methods: High-resolution three-dimensional T1-weighted MRI datasets from 251 patients with sporadic ALS, 19 symptomatic and 32 presymptomatic ALS mutation carriers and 112 healthy controls (HC) were retrospectivally registered for manual delineation of the hypothalamus. The volume of the hypothalamus, in total or subdivided, was normalised to the intracranial volume and adjusted to age. Correlation analyses were performed with clinical and metabolic outcomes. Pathologically defined ALS stages were determined in vivo by diffusion tensor imaging (DTI).Results: We observed a severe atrophy of the hypothalamus both in patients with sporadic ALS (-21.8%, p

Neuromuscular junction (NMJ) disruption is an early pathogenic event in amyotrophic lateral sclerosis (ALS). Yet, direct links between NMJ pathways and ALS-associated genes such as FUS, whose heterozygous mutations cause aggressive forms of ALS, remain elusive. In a knock-in Fus-ALS mouse model, we identified postsynaptic NMJ defects in newborn homozygous mutants that were attributable to mutant FUS toxicity in skeletal muscle. Adult heterozygous knock-in mice displayed smaller neuromuscular endplates that denervated before motor neuron loss, which is consistent with 'dying-back' neuronopathy. FUS was enriched in subsynaptic myonuclei, and this innervation-dependent enrichment was distorted in FUS-ALS. Mechanistically, FUS collaborates with the ETS transcription factor ERM to stimulate transcription of acetylcholine receptor genes. Co-cultures of induced pluripotent stem cell-derived motor neurons and myotubes from patients with FUS-ALS revealed endplate maturation defects due to intrinsic FUS toxicity in both motor neurons and myotubes. Thus, FUS regulates acetylcholine receptor gene expression in subsynaptic myonuclei, and muscle-intrinsic toxicity of ALS mutant FUS may contribute to dying-back motor neuronopathy.

Amyotrophic lateral sclerosis (ALS) is a disease of paradoxes. Patients usually have little or no medical history and tend to be fit and athletic,1 2 yet undergo a rapid, unrelenting decline. Patients predominantly present with progressive weakness, with involvement of cortical motor neurons and as the disease progresses, patients develop denervation, muscle atrophy, decreased muscle mass and decreased free fat mass, all of which would be expected to decrease energy expenditure.3 Yet patients with ALS are consistently hypermetabolic, with increased resting energy expenditure evident in up to 50% of patients.4 Several variables have been hypothesised to contribute to this hypermetabolic state, including uncontrolled fasciculations, increased respiratory work and mitochondrial dysfunction,4 yet the exact mechanism remains to be elucidated. In their JNNP paper Steyn and colleagues5 aim to …

International audience; Importance: Knowledge about the metabolic states of patients with amyotrophic lateral sclerosis (ALS) may provide a therapeutic approach.Objective: To investigate the association between the onset and prognosis of ALS and serum retinol-binding protein 4 (RBP4) concentration as a biomarker for insulin resistance and vitamin A metabolism.Design, setting, and participants: Case-control design for risk factors of ALS; cohort design for prognostic factors within ALS cases. Between October 1, 2010, and June 30, 2014, a population-based case-control study with randomly selected controls was established based on the ALS Registry Swabia in southern Germany, with a target population of 8.4 million inhabitants. Response rates were 64.8% among the cases and 18.7% among the controls. The dates of analysis were April 2016 to May 2017.Main outcomes and measures: Serum samples were measured for RBP4. Information on covariates was assessed by an interview-based standardized questionnaire. Main outcomes and measures were adjusted odds ratios for risk of ALS associated with serum RBP4 concentration, as well as time to death associated with RBP4 concentration at baseline in ALS cases only. Conditional logistic regression was applied to calculate multivariable odds ratios for risk of ALS. Survival models were used in cases only to appraise their prognostic value.Results: Data from 289 patients with ALS (mean [SD] age, 65.7 [10.5] years; 172 [59.5%] male) and 504 controls (mean [SD] age, 66.3 [9.8] years; 299 [59.3%] male) were included in the case-control study. Compared with controls, ALS cases were characterized by lower body mass index, less educational attainment, smoking, light occupational work intensity, and self-reported diabetes. The median serum RBP4 concentration was lower in ALS cases than in controls (54.0 vs 59.5 mg/L). In the multivariable model, increasing RBP4 concentration was associated with reduced odds for ALS (top vs bottom quartile odds ratio, 0.36; 95% CI, 0.22-0.59; P for trend

International audience; Amyotrophic lateral sclerosis (ALS) is the major adult-onset motor neuron disease, and is clinically, pathologically, and genetically associated with frontotemporal dementia, the second cause of dementia in the elderly. Here, we review the evidence linking thermoregulation and ALS. Indeed, while ALS is not classically associated with defective thermoregulatory function, its progression severely affects key brain regions controlling body temperature and impacts multiple sensors and effectors of this homeostatic function. Furthermore, animal models of ALS display disturbed thermoregulation as a consequence of disrupted energy homeostasis. All these lines of indirect evidence call for studies directly addressing the body temperature regulatory system, both as a potential biomarker and as a possible modifier of disease progression in ALS.

The primarily nuclear RNA-binding protein FUS (fused in sarcoma) forms pathological cytoplasmic inclusions in a subset of early-onset amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) patients. In response to cellular stress, FUS is recruited to cytoplasmic stress granules, which are hypothesized to act as precursors of pathological inclusions. We monitored the stress-induced nucleocytoplasmic shuttling of endogenous FUS in an ex vivo mouse CNS model and human neural networks. We found that hyperosmolar, but not oxidative, stress induced robust cytoplasmic translocation of neuronal FUS, with transient nuclear clearance and loss of function. Surprisingly, this reaction is independent of stress granule formation and the molecular pathways activated by hyperosmolarity. Instead, it represents a mechanism mediated by cytoplasmic redistribution of Transportin 1/2 and is potentiated by transcriptional inhibition. Importantly, astrocytes, which remain unaffected in ALS/FTD-FUS, are spared from this stress reaction that may signify the initial event in the development of FUS pathology., Cell Reports, 24 (4), ISSN:2666-3864, ISSN:2211-1247

Weight loss is increasingly considered as a negative prognostic marker in amyotrophic lateral sclerosis (ALS). Despite the critical importance of nutritional issues in ALS, and the common use of percutaneous endoscopic gastrostomy (PEG), there is a general lack of knowledge on peri-interventional treatment, optimal parameters of enteral nutrition, its timing during disease progression and its potential disease-modifying effects in ALS patients. Here we report the results of a multi-center prospective study of percutaneous endoscopic gastrostomy (PEG) in ALS. In this observational clinical trial, 89 ALS patients were prospectively enrolled over a 3-year period and longitudinal data were collected over 18 months. PEG was a safe procedure even in patients with low forced vital capacity, and prophylactic single-shot antibiosis as well as slow increase of caloric nutrition via PEG was beneficial to avoid complications. No signs of refeeding syndrome were observed. High-caloric intake (>1,500 kcal/d) via PEG in patients that lived at least 12 months after PEG insertion was correlated with prolonged survival. Additional oral food intake was not associated with a worse prognosis. Our results suggest that peri-interventional PEG management should include prophylactic single-shot antibiosis, slow increase of caloric intake, and long-term high-caloric nutrition. Although our results indicate that PEG might be more beneficial when applied early, we believe that it can also be performed safely in patients with far advanced disease. Because of its explorative and observational character, most of our results have to be confirmed by a randomized interventional trial.

Mutations in components of the molecular motor dynein/dynactin lead to neurodegenerative diseases of the motor system or atypical parkinsonism. These mutations are associated with prominent accumulation of vesicles involved in autophagy and lysosomal pathways, and with protein inclusions. Whether alleviating these defects would affect motor symptoms remain unknown. Here, we show that a mouse model expressing low levels of disease linked-G59S mutant dynactin p150(Glued) develops motor dysfunction >8 months before loss of motor neurons or dopaminergic degeneration is observed. Abnormal accumulation of autophagosomes and protein inclusions were efficiently corrected by lowering dietary protein content, and this was associated with transcriptional upregulations of key players in autophagy. Most importantly this dietary modification partially rescued overall neurological symptoms in these mice after onset. Similar observations were made in another mouse strain carrying a point mutation in the dynein heavy chain gene. Collectively, our data suggest that stimulating the autophagy/lysosomal system through appropriate nutritional intervention has significant beneficial effects on motor symptoms of dynein/dynactin diseases even after symptom onset.

International audience; Weight loss appears as a strong predictor of survival of patients with amyotrophic lateral sclerosis, yet no data are currently available to describe the life course history of pre-diagnostic body mass index (BMI) in these patients. 393 ALS cases (mean age: 65.8 years, 57.3% men) and 791 controls matched by age and sex from a population-based case-control study of the ALS Registry Swabia were analyzed. Differences of BMI change in cases and controls over time were modeled using a multilevel additive model. In addition, survival in ALS cases by BMI change was modeled using an accelerated failure time model adjusted for prognostic factors. In ALS cases, BMI was consistently higher than in controls in the 20-70 years before the interview. Conditional logistic regression revealed an odds ratio of 1.05 (95% confidence interval (CI) 1.00-1.11, p = 0.041) per 1 kg/m2 higher BMI 35-45 years before interview. However, a sharp decrease was evident in the BMI of ALS cases about 10 years before disease onset. Moreover, weight loss was strongly associated with shorter survival in ALS patients. Illustrating this, patients with stable weight showed a median survival time of 22.1 (95%-CI 19.2-25.0) months, as compared to 13.4 (95%-CI 10.5-16.3) months for patients with weight loss of 2.5 kg/m2 over the last 3 months before the interview. Thus, alterations in body weight are present in ALS patients already decades before clinical manifestation of ALS, while weight loss precedes motor symptoms of several years and is associated with poor prognosis.

Neurodegenerative diseases (NDDs) are disorders characterized by progressive deterioration of brain structure and function. Selective neuronal populations are affected leading to symptoms which are prominently motor in amyotrophic lateral sclerosis (ALS) or Huntington’s disease (HD), or cognitive in Alzheimer’s disease (AD) and fronto-temporal dementia (FTD). Besides the common existence of neuronal loss, NDDs are also associated with metabolic changes such as weight gain, weight loss, loss of fat mass, as well as with altered feeding behavior. Importantly, preclinical research as well as clinical studies have demonstrated that altered energy homeostasis influences disease progression in ALS, AD and HD, suggesting that identification of the pathways leading to perturbed energy balance might provide valuable therapeutic targets Signals from both the periphery and central inputs are integrated in the hypothalamus, a major hub for the control of energy balance. Recent research identified major hypothalamic changes in multiple NDDs. Here, we review these hypothalamic alterations and seek to identify commonalities and differences in hypothalamic involvement between the different NDDs. These hypothalamic defects could be key in the development of perturbations in energy homeostasis in NDDs and further understanding of the underlying mechanisms might open up new avenues to not only treat weight loss but also to ameliorate overall neurological symptoms.

International audience; Background: Monogenetic forms of amyotrophic lateral sclerosis (ALS) offer an opportunity for unraveling the molecular mechanisms underlying this devastating neurodegenerative disorder. In order to identify a link between ALS-related metabolic changes and neurodegeneration, we investigated whether ALS-causing mutations interfere with the peripheral and brain-specific expression and signaling of the metabolic master regulator PGC (PPAR gamma coactivator)-1α (PGC-1α).Methods: We analyzed the expression of PGC-1α isoforms and target genes in two mouse models of familial ALS and validated the stimulated PGC-1α signaling in primary adipocytes and neurons of these animal models and in iPS derived motoneurons of two ALS patients harboring two different frame-shift FUS/TLS mutations.Results: Mutations in SOD1 and FUS/TLS decrease Ppargc1a levels in the CNS whereas in muscle and brown adipose tissue Ppargc1a mRNA levels were increased. Probing the underlying mechanism in neurons, we identified the monocarboxylate lactate as a previously unrecognized potent and selective inducer of the CNS-specific PGC-1α isoforms. Lactate also induced genes like brain-derived neurotrophic factor, transcription factor EB and superoxide dismutase 3 that are down-regulated in PGC-1α deficient neurons. The lactate-induced CNS-specific PGC-1α signaling system is completely silenced in motoneurons derived from induced pluripotent stem cells obtained from two ALS patients harboring two different frame-shift FUS/TLS mutations.Conclusion: ALS mutations increase the canonical PGC-1α system in the periphery while inhibiting the CNS-specific isoforms. We identify lactate as an inducer of the neuronal PGC-1α system directly linking brain metabolism and neuroprotection. Changes in the PGC-1α system might be involved in the ALS accompanied metabolic changes and in neurodegeneration.

International audience; Introduction: There is some evidence that Parkinson's Disease (PD) patients have lower body weight and lower fat mass when compared to healthy subjects and that lower body weight and fat mass influence disease risk and progression. It remains unclear, however, if weight loss of fat mass loss occurs only in a subgroup of patients and whether fat distribution is altered during PD. The aim of this study was to prospectively investigate adipose tissue content and distribution in PD patients.Methods: The body fat composition of PD patients (N = 54) was compared with age matched healthy controls (N = 55) using a magnetic resonance imaging (MRI)-based method. A longitudinal MRI scan was acquired in 25 PD patients after a mean follow up period of 12 months.Results: The volume of total body fat as well as of visceral fat showed no difference between PD patients and healthy controls at baseline or at follow up. However, PD patients displayed decreased subcutaneous fat tissue (p = 0.01) and a higher visceral to subcutaneous fat ratio as compared to controls (p = 0.004). After follow up, 16 PD patients did not lose weight, while 9 PD patients lost between 0.5 and 10 kg.Conclusion: Fat distribution is altered in PD patients, with an increased ratio of visceral to subcutaneous fat.

The last 30 years have seen a major advance in the understanding of the clinical and pathological heterogeneity of amyotrophic lateral sclerosis (ALS), and its overlap with frontotemporal dementia. Multiple, seemingly disparate biochemical pathways converge on a common clinical syndrome characterized by progressive loss of upper and lower motor neurons. Pathogenic themes in ALS include excitotoxicity, oxidative stress, mitochondrial dysfunction, neuroinflammation, altered energy metabolism, and most recently RNA mis-processing. The transgenic rodent, overexpressing mutant superoxide dismutase-1, is now only one of several models of ALS pathogenesis. The nematode, fruit fly and zebrafish all offer fresh insight, and the development of induced pluripotent stem cell-derived motor neurons holds promise for the screening of candidate therapeutics. The lack of useful biomarkers in ALS contributes to diagnostic delay, and the inability to stratify patients by prognosis may be an important factor in the failure of therapeutic trials. Biomarkers sensitive to disease activity might lessen reliance on clinical measures and survival as trial endpoints and reduce study length. Emerging proteomic markers of neuronal loss and glial activity in cerebrospinal fluid, a cortical signature derived from advanced structural and functional MRI, and the development of more sensitive measurements of lower motor neuron physiology are leading a new phase of biomarker-driven therapeutic discovery.

Spasticity is a common and disabling symptom observed in patients with central nervous system diseases, including amyotrophic lateral sclerosis, a disease affecting both upper and lower motor neurons. In amyotrophic lateral sclerosis, spasticity is traditionally thought to be the result of degeneration of the upper motor neurons in the cerebral cortex, although degeneration of other neuronal types, in particular serotonergic neurons, might also represent a cause of spasticity. We performed a pathology study in seven patients with amyotrophic lateral sclerosis and six control subjects and observed that central serotonergic neurons suffer from a degenerative process with prominent neuritic degeneration, and sometimes loss of cell bodies in patients with amyotrophic lateral sclerosis. Moreover, distal serotonergic projections to spinal cord motor neurons and hippocampus systematically degenerated in patients with amyotrophic lateral sclerosis. In SOD1 (G86R) mice, a transgenic model of amyotrophic lateral sclerosis, serotonin levels were decreased in brainstem and spinal cord before onset of motor symptoms. Furthermore, there was noticeable atrophy of serotonin neuronal cell bodies along with neuritic degeneration at disease onset. We hypothesized that degeneration of serotonergic neurons could underlie spasticity in amyotrophic lateral sclerosis and investigated this hypothesis in vivo using tail muscle spastic-like contractions in response to mechanical stimulation as a measure of spasticity. In SOD1 (G86R) mice, tail muscle spastic-like contractions were observed at end-stage. Importantly, they were abolished by 5-hydroxytryptamine-2b/c receptors inverse agonists. In line with this, 5-hydroxytryptamine-2b receptor expression was strongly increased at disease onset. In all, we show that serotonergic neurons degenerate during amyotrophic lateral sclerosis, and that this might underlie spasticity in mice. Further research is needed to determine whether inverse agonists of 5-hydroxytryptamine-2b/c receptors could be of interest in treating spasticity in patients with amyotrophic lateral sclerosis.

The mutations P56S and T46I in the gene encoding vesicle-associated membrane protein-associated protein B/C (VAPB) cause ALS8, a familial form of amyotrophic lateral sclerosis (ALS). Overexpression of mutant forms of VAPB leads to cytosolic aggregates, suggesting a gain of function of the mutant protein. However, recent work suggested that the loss of VAPB function could be the major mechanism leading to ALS8. Here, we used multiple genetic and experimental approaches to study whether VAPB loss of function might be sufficient to trigger motor neuron degeneration. In order to identify additional ALS-associated VAPB mutations, we screened the entire VAPB gene in a cohort of ALS patients and detected two mutations (A145V and S160Δ). To directly address the contribution of VAPB loss of function in ALS, we generated zebrafish and mouse models with either a decreased or a complete loss of Vapb expression. Vapb knockdown in zebrafish led to swimming deficits. Mice knocked-out for Vapb showed mild motor deficits after 18 months of age yet had innervated neuromuscular junctions (NMJs). Importantly, overexpression of VAPB mutations were unable to rescue the motor deficit caused by Vapb knockdown in zebrafish and failed to cause a toxic gain-of-function defect on their own. Thus, Vapb loss of function weakens the motor system of vertebrate animal models but is on its own unable to lead to a complete ALS phenotype. Our findings are consistent with the notion that VAPB mutations constitute a risk factor for motor neuron disease through a loss of VAPB function.

International audience; FUS is an RNA-binding protein involved in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Cytoplasmic FUS-containing aggregates are often associated with concomitant loss of nuclear FUS Whether loss of nuclear FUS function, gain of a cytoplasmic function, or a combination of both lead to neurodegeneration remains elusive. To address this question, we generated knockin mice expressing mislocalized cytoplasmic FUS and complete FUS knockout mice. Both mouse models display similar perinatal lethality with respiratory insufficiency, reduced body weight and length, and largely similar alterations in gene expression and mRNA splicing patterns, indicating that mislocalized FUS results in loss of its normal function. However, FUS knockin mice, but not FUS knockout mice, display reduced motor neuron numbers at birth, associated with enhanced motor neuron apoptosis, which can be rescued by cell-specific CRE-mediated expression of wild-type FUS within motor neurons. Together, our findings indicate that cytoplasmic FUS mislocalization not only leads to nuclear loss of function, but also triggers motor neuron death through a toxic gain of function within motor neurons.

International audience; Microglia are the resident mononuclear phagocytes of the central nervous system and have been implicated in the pathogenesis of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS). During neurodegeneration, microglial activation is accompanied by infiltration of circulating monocytes, leading to production of multiple inflammatory mediators in the spinal cord. Degenerative alterations in mononuclear phagocytes are commonly observed during neurodegenerative diseases, yet little is known concerning the mechanisms leading to their degeneration, or the consequences on disease progression. Here we observed that the serotonin 2B receptor (5-HT2B), a serotonin receptor expressed in microglia, is upregulated in the spinal cord of three different transgenic mouse models of ALS. In mutant SOD1 mice, this upregulation was restricted to cells positive for CD11b, a marker of mononuclear phagocytes. Ablation of 5-HT2B receptor in transgenic ALS mice expressing mutant SOD1 resulted in increased degeneration of mononuclear phagocytes, as evidenced by fragmentation of Iba1-positive cellular processes. This was accompanied by decreased expression of key neuroinflammatory genes but also loss of expression of homeostatic microglial genes. Importantly, the dramatic effect of 5-HT2B receptor ablation on mononuclear phagocytes was associated with acceleration of disease progression. To determine the translational relevance of these results, we studied polymorphisms in the human HTR2B gene, which encodes the 5-HT2B receptor, in a large cohort of ALS patients. In this cohort, the C allele of SNP rs10199752 in HTR2B was associated with longer survival. Moreover, patients carrying one copy of the C allele of SNP rs10199752 showed increased 5-HT2B mRNA in spinal cord and displayed less pronounced degeneration of Iba1 positive cells than patients carrying two copies of the more common A allele. Thus, the 5-HT2B receptor limits degeneration of spinal cord mononuclear phagocytes, most likely microglia, and slows disease progression in ALS. Targeting this receptor might be therapeutically useful.

Summary Studying ciliopathies, like the Bardet-Biedl syndrome (BBS), allow the identification of signaling pathways potentially involved in common diseases, sharing phenotypic features like obesity or type 2 diabetes. Given the close association between obesity and insulin resistance, obese BBS patients would be expected to be insulin resistant. Surprisingly, we found that a majority of obese BBS patients retained normal glucose tolerance and insulin sensitivity. Patient's adipose tissue biopsies revealed upregulation of adipogenic genes and decrease of inflammatory mediators. In vitro studies on human primary mesenchymal stem cells (MSCs) showed that BBS12 inactivation facilitated adipogenesis, increased insulin sensitivity, and glucose utilization. We generated a Bbs12 −/− mouse model to assess the impact of Bbs12 inactivation on adipocyte biology. Despite increased obesity, glucose tolerance was increased with specific enhanced insulin sensitivity in the fat. This correlated with an active recruitment of MSCs resulting in adipose tissue hyperplasia and decreased in inflammation.

Amyotrophic lateral sclerosis (ALS) is characterised by the progressive degeneration of upper and lower motor neurons. Besides motor neuron degeneration, ALS is associated with several defects in energy metabolism, including weight loss, hypermetabolism, and hyperlipidaemia. Most of these abnormalities correlate with duration of survival, and available clinical evidence supports a negative contribution of defective energy metabolism to the overall pathogenic process. Findings from animal models of ALS support this view and provide insights into the underlying mechanisms. Altogether, these results have clinical consequences for the management of defective energy metabolism in patients with ALS and pave the way for future therapeutic interventions.

Motor neuron degeneration and progressive muscle atrophy characterize amyotrophic lateral sclerosis (ALS) in humans and related mutant superoxide dismutase-1 (SOD1) transgenic mice. Our previous microarray studies on ALS muscle revealed strong up-regulation of Ras-related associated with diabetes (Rad), an inhibitor of voltage-gated calcium channels. The mechanisms controlling Rad expression in disease are unknown. We analyzed Rad expression in skeletal muscle from ALS patients and animal models and investigated whether it is regulated by oxidative stress. In mutant SOD1 mice, Rad up-regulation preceded motor symptoms and markedly increased as disease progressed. Increased Rad expression was also obtained in surgically denervated muscle. No clinical signs of denervation were seen in asymptomatic mice, however. We therefore suspected that muscular mutant SOD1 toxicity causes precocious Rad up-regulation. We confirmed the accumulation of reactive oxygen species (ROS) at asymptomatic stages, coincident with the rise in Rad expression. By subjecting muscle to ischemia-reperfusion, we observed ROS accumulation and Rad overexpression. The cell-permeative antioxidant Tempol inhibited the stimulatory effect of ischemia-reperfusion. Tempol also reduced Rad up-regulation after experimental denervation. Our study provides strong evidence for the implication of oxidative stress in modulating Rad expression, in association with the initiation and progression of ALS muscle atrophy.

The efflux pumps located at the blood-brain barrier (BBB) prevent drugs entering the brain. As such, efflux pumps are a major obstacle to drug brain distribution. Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with little therapeutics available: riluzole is the only drug approved in its treatment. The lack of response to treatment in ALS may be, at least in part, due to increased activities of efflux pumps in relation to disease, leading to subtherapeutic brain concentrations of drugs. In the present study, we used a transgenic mouse model of ALS (G86R mSOD1 mice) to test this hypothesis. Expression and functionality of P-glycoprotein (ABCB1, P-gp) and Breast Cancer Resistance Protein (ABCG2, BCRP), two major efflux pumps, were studied. We observed an increased P-gp expression (1.5-fold) in presymptomatic mSOD1 mice compared to wild-type controls. Consistent with this, P-gp function was also increased by 1.5-fold and riluzole brain disposition was decreased by 1.7-fold in mSOD1 mice. Contrasting with this, BCRP expression and function were unaltered by the pathology. These results demonstrate that BBB transport proteins are modified in G86R mSOD1 mice ALS model. Such findings underline potential problems in extrapolating the results of animal studies to humans and developing clinical trials, especially for drugs transported by P-gp.

Our objectives were to analyse carbohydrate metabolism in a series of ALS patients and to examine potential association with parameters of lipid metabolism and clinical features. Glucose tolerance was assessed by the oral glucose tolerance test in 21 non-diabetic ALS patients and compared with 21 age- and sex-matched normal subjects. Lipids and lactate/pyruvate ratio, levels of pro-inflammatory cytokines (tumour necrosis factor-alpha and interleukin-6) and adipocytokines (leptin and adiponectin) were also measured in ALS patients. Mann-Whitney U-tests analysed continuous data and Fisher's exact tests assessed categorical data. Blood glucose determined 120 min after the glucose bolus was significantly higher in patients with ALS (7.41 mmol/l+/-1.68) compared to controls (6.05+/-1.44, p=0.006). ALS patients with impaired glucose tolerance (IGT) according to WHO criteria (n=7, 33%) were more likely to have elevated free fatty acids (FFA) levels compared to patients with normal glucose tolerance (0.77 nmol/l+/-0.30 vs. 0.57+/-0.19, p=0.04). IGT was not associated with disease duration or severity. In conclusion, patients with ALS show abnormal glucose tolerance that could be associated with increased FFA levels, a key determinant of insulin resistance. The origin of glucose homeostasis abnormalities in ALS may be multifactorial and deserves further investigation.

In neurons, cytoplasmic dynein functions as a molecular motor responsible for retrograde axonal transport. An impairment of axonal transport is thought to play a key role in the pathogenesis of neurodegenerative diseases such as amyotrophic lateral sclerosis, the most frequent motor neuron disease in the elderly. In this regard, previous studies described two heterozygous mouse strains bearing missense point mutations in the dynein heavy chain 1 gene that were reported to display late-onset progressive motor neuron degeneration. Here we show, however, that one of these mutant strains, the so-called Cra mice does not suffer from motor neuron loss, even in aged animals. Consistently, we did not observe electrophysiological or biochemical signs of muscle denervation, indicative of motor neuron disease. The "hindlimb clasping" phenotype of Cra mice could rather be due to the prominent degeneration of sensory neurons associated with a loss of muscle spindles. Altogether, these findings show that dynein heavy chain mutation triggers sensory neuropathy rather than motor neuron disease.

Objective A proportion of patients with pure lower motor neuron syndrome (LMNS) progress to amyotrophic lateral sclerosis (ALS). Early detection of this progression is impossible, which delays the patient's access to treatment. Muscle expression of Nogo-A is a new candidate marker of ALS. We tested whether detection of Nogo-A in a muscle biopsy from patients with LMNS predicts progression to ALS. Methods Thirty-three patients who had undergone a muscle biopsy during the diagnostic workup of spinal LMNS were observed for 12 months. Nogo-A expression was measured by Western blot in muscle biopsy samples and compared with the final diagnosis. Results Nogo-A expression was detected in 17 patients and was absent in 16 patients. The detection of Nogo-A in muscle biopsy samples from LMNS patients correctly identified patients who further progressed to ALS with 91% accuracy, 94% sensitivity, and 88% specificity. In patients who later developed typical ALS, Nogo-A may be detected as early as 3 months after the onset of symptoms. Interpretation Nogo-A test is able to identify ALS early in the course of the disease when diagnosis is difficult, requiring further progression. Use of the test in clinical practice may shorten the delay before introduction of neuroprotective drugs or inclusion in clinical trials. Ann Neurol 2007

Amyotrophic lateral sclerosis (ALS) is the most frequent adult-onset motor neuron disease characterized by degeneration of upper and lower motor neurons, generalized weakness and muscle atrophy. Most cases of ALS appear sporadically but some forms of the disease result from mutations in the gene encoding the antioxidant enzyme Cu/Zn superoxide dismutase (SOD1). Several other mutated genes have also been found to predispose to ALS including, among others, one that encodes the regulator of axonal retrograde transport dynactin. As all roads lead to the proverbial Rome, we discuss here how distinct molecular pathways may converge to the same final result that is motor neuron death. We critically review the basic research on SOD1-linked ALS to propose a pioneering model of a 'systemic' form of the disease, causally involving multiple cell types, either neuronal or non-neuronal. Contrasting this, we also postulate that other neuron-specific defects, as those triggered by dynactin dysfunction, may account for a primary motor neuron disease that would represent 'pure' neuronal forms of ALS. Identifying different disease subtypes is an unavoidable step toward the understanding of the physiopathology of ALS and will hopefully help to design specific treatments for each subset of patients.

Background Total and central adiposity have been associated with increased risk of Alzheimer's disease (AD). Visceral and subcutaneous adipose tissues have different metabolic characteristics and could therefore be differentially associated with AD. Objective To compare regional fat distribution determined by magnetic resonance imaging (MRI) in AD patients and healthy controls and investigate associations with stage of the disease and chemical markers. The investigation was performed in a prospective case-control study. Methods We examined thirty patients with mild to moderate AD by whole-body MRI (1.5 T) and clinical questionnaires in comparison to thirty cognitively healthy age- and gender-matched study participants. Volumes of total, subcutaneous, and visceral body fat tissue were determined by an unbiased automatic analysis algorithm. Levels of leptin, ghrelin, and adiponectin were determined in serum, amyloid-β (Aβ)(1-42) and tau protein levels in cerebrospinal fluid (CSF). Results Male AD patients displayed significantly more total fat tissue than male controls. This difference was not observed in women. We observed a trend toward higher volume of visceral fat tissue in all patients (p = 0.13). Severity of disease was not associated with fat distribution in our study. Increased leptin levels correlated with lower CSF Aβ(1-42) in female, but not in male, AD patients. Conclusions Fat volume is increased in male, but not in female AD patients. Negative correlation of leptin levels and CSF Aβ(1-42) in females might be one co-factor for the increased AD risk of females. Further studies are required to confirm this gender difference in fat volume during AD and evaluate its pathophysiological importance.

Nogo, a protein inhibiting axonal regeneration, exhibits a characteristic isoform-specific pattern of expression in skeletal muscle of transgenic mice and patients with amyotrophic lateral sclerosis. Here, the increased levels of Nogo-A or Nogo-B in muscle biopsies of 15 amyotrophic lateral sclerosis patients significantly correlated with the severity of clinical disability and with the degree of muscle fiber atrophy. Nogo-A immunoreactivity was observed selectively in atrophic slow-twitch type I fibers. These results suggest that Nogo expression in muscle is a marker of amyotrophic lateral sclerosis severity.

A subset of familial ALS cases is associated with missense mutations in the gene encoding Cu/Zn-superoxide dismutase (SOD1), a free radical scavenging enzyme that protects cells against oxidative stress. Overexpression of these ALS-linked mutations confers an unidentified gain of function to the enzyme that triggers a series of neurological disorders characteristic of human ALS. To understand how skeletal muscle may counteract the progression of the disease, we explored the expression of different molecular effectors involved in antioxidant pathways. Our results are strongly indicative of the early and long-lasting activation of a series of molecular effectors thought to act coordinately in preventing the increased oxidative stress characteristic of ALS.

The nervous system plays a key role in the regulation of neuroendocrine axes and, in turn, the released neurohormones modulate the activity of different brain regions. Neurodegenerative diseases, which are known to affect specific neuronal populations, may provoke neuroendocrine dysfunctions that alter the intimate relationship between both systems. In addition, these modifications may influence the progression of the neurodegenerative process. In the present review, we summarise some of the endocrine changes characterising three major neurodegenerative diseases: Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis. Special attention is focused on the contribution of disease transgenic models to elucidate such alterations.

Amyotrophic lateral sclerosis (ALS) is a fatal neurological disorder characterized by the selective degeneration of upper and lower motor neurons. The lack of a molecular diagnostic marker is of increasing concern in view of the therapeutic strategies in development. Using an unbiased subtractive suppressive hybridization screen we have identified a clone encoding the neurite outgrowth inhibitor Nogo and shown that its isoforms display a characteristic altered expression in ALS. This was first confirmed by analyzing Nogo isoform expression in a transgenic ALS model at early asymptomatic stages where we found increased levels of Nogo-A and decreased Nogo-C and importantly, not following experimentally induced denervation. Furthermore, we confirmed these changes in both post-mortem and biopsy samples from diagnosed ALS patients but not control patients. Thus, the alteration in Nogo expression pattern, common to sporadic and familial ALS, represents a potential diagnosis tool and points strongly to Nogo having a central role in disease.