Showing papers on "Amyotrophic lateral sclerosis published in 2006"

Ubiquitinated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis

Abstract: Ubiquitin-positive, tau- and alpha-synuclein-negative inclusions are hallmarks of frontotemporal lobar degeneration with ubiquitin-positive inclusions and amyotrophic lateral sclerosis. Although the identity of the ubiquitinated protein specific to either disorder was unknown, we showed that TDP-43 is the major disease protein in both disorders. Pathologic TDP-43 was hyper-phosphorylated, ubiquitinated, and cleaved to generate C-terminal fragments and was recovered only from affected central nervous system regions, including hippocampus, neocortex, and spinal cord. TDP-43 represents the common pathologic substrate linking these neurodegenerative disorders.

Onset and Progression in Inherited ALS Determined by Motor Neurons and Microglia

Abstract: Dominant mutations in superoxide dismutase cause amyotrophic lateral sclerosis (ALS), a progressive paralytic disease characterized by loss of motor neurons. With the use of mice carrying a deletable mutant gene, expression within motor neurons was shown to be a primary determinant of disease onset and of an early phase of disease progression. Diminishing the mutant levels in microglia had little effect on the early disease phase but sharply slowed later disease progression. Onset and progression thus represent distinct disease phases defined by mutant action within different cell types to generate non-cell-autonomous killing of motor neurons; these findings validate therapies, including cell replacement, targeted to the non-neuronal cells.

Molecular biology of amyotrophic lateral sclerosis: insights from genetics.

Abstract: Amyotrophic lateral sclerosis (ALS) is a paralytic disorder caused by motor neuron degeneration. Mutations in more than 50 human genes cause diverse types of motor neuron pathology. Moreover, defects in five Mendelian genes lead to motor neuron disease, with two mutations reproducing the ALS phenotype. Analyses of these genetic effects have generated new insights into the diverse molecular pathways involved in ALS pathogenesis. Here, we present an overview of the mechanisms for motor neuron death and of the role of non-neuronal cells in ALS.

ANG mutations segregate with familial and 'sporadic' amyotrophic lateral sclerosis

Abstract: We recently identified angiogenin (ANG) as a candidate susceptibility gene for amyotrophic lateral sclerosis (ALS), a neurodegenerative disorder characterized by adult-onset loss of motor neurons. We now report the finding of seven missense mutations in 15 individuals, of whom four had familial ALS and 11 apparently 'sporadic' ALS. Our findings provide further evidence that variations in hypoxia-inducible genes have an important role in motor neuron degeneration.

Familial amyotrophic lateral sclerosis with frontotemporal dementia is linked to a locus on chromosome 9p13.2–21.3

Abstract: Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are both relentlessly progressive and ultimately fatal neurological disorders. ALS is familial in approximately 10% of cases and FTD in approximately 30%. Inheritance is usually autosomal dominant with variable penetrance. Phenotypic overlap between ALS and FTD can occur within the same kindred. Mutations in copper/zinc superoxide dismutase 1 (SOD1) are found in approximately 20% of familial and approximately 3% of sporadic ALS cases but are not associated with dementia. Mutations in microtubule associated protein tau (MAPT) are detected in approximately 30% of familial FTD kindreds. Dominant ALS with FTD has previously been linked to 9q21 and pure ALS to loci on 16q21, 18q21, 20p13. Here we report the results of a genome-wide linkage study in a large ALS and FTD kindred using Affymetrix 10K GeneChip microarrays. Linkage analysis of single nucleotide polymorphism (SNP) data identified consistently positive log of the odds (LOD) scores across chromosome 9p (maximal LOD score of 2.4). Fine mapping the region with microsatellite markers generated a maximal multipoint LOD score of 3.02 (theta = 0) at D9S1878. Recombination narrowed the conserved haplotype to 12 cM (11 Mb) at 9p13.2-21.3 (flanking markers D9S2154 and D9S1874). Bioinformatic analysis of the region has identified 103 known genes.

Complete dissociation of motor neuron death from motor dysfunction by Bax deletion in a mouse model of ALS.

Abstract: The death of cranial and spinal motoneurons (MNs) is believed to be an essential component of the pathogenesis of amyotrophic lateral sclerosis (ALS). We tested this hypothesis by crossing Bax-deficient mice with mice expressing mutant superoxide dismutase 1 (SOD1), a transgenic model of familial ALS. Although Bax deletion failed to prevent neuromuscular denervation and mitochondrial vacuolization, MNs were completely rescued from mutant SOD1-mediated death. However, Bax deficiency extended lifespan and delayed the onset of motor dysfunction of SOD1 mutants, suggesting that Bax acts via a mechanism distinct from cell death activation. Consistent with this idea, Bax elimination delayed the onset of neuromuscular denervation, which began long before the activation of cell death proteins in SOD1 mutants. Additionally, we show that denervation preceded accumulation of mutant SOD1 within MNs and astrogliosis in the spinal cord, which are also both delayed in Bax-deficient SOD1 mutants. Interestingly, MNs exhibited mitochondrial abnormalities at the innervated neuromuscular junction at the onset of neuromuscular denervation. Additionally, both MN presynaptic terminals and terminal Schwann cells expressed high levels of mutant SOD1 before MNs withdrew their axons. Together, these data support the idea that clinical symptoms in the SOD1 G93A model of ALS result specifically from damage to the distal motor axon and not from activation of the death pathway, and cast doubt on the utility of anti-apoptotic therapies to combat ALS. Furthermore, they suggest a novel, cell death-independent role for Bax in facilitating mutant SOD1-mediated motor denervation.

Amyotrophic lateral sclerosis associated with mutations in the CuZn superoxide dismutase gene.

Abstract: This review highlights recent epidemiologic, clinical-genetic, and neurochemical advances in our understanding of sporadic amyotrophic lateral sclerosis (ALS) and their relationships to familial ALS caused by superoxide dismutase (SOD1) gene mutations. It is of fundamental importance to recognize that ALS is a biologically heterogeneous syndrome in which genetics, environment, and aging are inter-related. The discovery of mutations in the SOD1 gene is the greatest breakthrough in ALS research since Charcot's description of the disorder, but the putative toxic gain of function of mutant SOD1 remains elusive despite intense research. Currently, two dominant theories for the pathogenesis of SOD1 mutations exist: specific protein cytotoxicity and protein aggregation. Mutant SOD1 interacts specifically with neurofilament-light chain mRNA and the dynein/dynactin complex, suggesting that cytoskeletal defects and axonal transport are key players. In addition, mutant SOD1 protein has increased propensity to form aggregate-prone monomers, and the degree of instability correlates inversely with length of survival; therefore, increased propensity to aggregate may be the unifying common denominator for the 119 diverse SOD1 mutations.

Trial of celecoxib in amyotrophic lateral sclerosis.

Abstract: Objective: To determine whether chronic treatment with celecoxib, a cyclooxygenase-2 inhibitor that has been shown to be beneficial in preclinical testing, is safe and effective in amyotrophic lateral sclerosis (ALS). Methods: A double-blind, placebo-controlled, clinical trial was conducted. Three hundred research subjects with ALS were randomized (2:1) to receive celecoxib (800mg/day) or placebo for 12 months. The primary outcome measure was the rate of change in upper extremity motor function measured by the maximum voluntary isometric contraction strength. Secondary end points included safety, survival, change in cerebrospinal fluid prostaglandin E2 levels, and changes in the rate of decline of leg and grip strength, vital capacity, ALS Functional Rating Scale-Revised, and motor unit number estimates. Results: Celecoxib did not slow the decline in muscle strength, vital capacity, motor unit number estimates, ALS Functional Rating Scale-Revised, or affect survival. Celecoxib was well tolerated and was not associated with an increased frequency of adverse events. Prostaglandin E2 levels in cerebrospinal fluid were not elevated at baseline and did not decline with treatment. Interpretation: At the dosage studied, celecoxib did not have a beneficial effect on research subjects with ALS, and it was safe. A biological effect of celecoxib was not demonstrated in the cerebrospinal fluid. Further studies of celecoxib at a dosage of 800mg/day in ALS are not warranted.

A ketogenic diet as a potential novel therapeutic intervention in amyotrophic lateral sclerosis

Abstract: The cause of neuronal death in amyotrophic lateral sclerosis (ALS) is uncertain but mitochondrial dysfunction may play an important role. Ketones promote mitochondrial energy production and membrane stabilization. SOD1-G93A transgenic ALS mice were fed a ketogenic diet (KD) based on known formulations for humans. Motor performance, longevity, and motor neuron counts were measured in treated and disease controls. Because mitochondrial dysfunction plays a central role in neuronal cell death in ALS, we also studied the effect that the principal ketone body, D-β-3 hydroxybutyrate (DBH), has on mitochondrial ATP generation and neuroprotection. Blood ketones were > 3.5 times higher in KD fed animals compared to controls. KD fed mice lost 50% of baseline motor performance 25 days later than disease controls. KD animals weighed 4.6 g more than disease control animals at study endpoint; the interaction between diet and change in weight was significant (p = 0.047). In spinal cord sections obtained at the study endpoint, there were more motor neurons in KD fed animals (p = 0.030). DBH prevented rotenone mediated inhibition of mitochondrial complex I but not malonate inhibition of complex II. Rotenone neurotoxicity in SMI-32 immunopositive motor neurons was also inhibited by DBH. This is the first study showing that diet, specifically a KD, alters the progression of the clinical and biological manifestations of the G93A SOD1 transgenic mouse model of ALS. These effects may be due to the ability of ketone bodies to promote ATP synthesis and bypass inhibition of complex I in the mitochondrial respiratory chain.

The inflammatory NADPH oxidase enzyme modulates motor neuron degeneration in amyotrophic lateral sclerosis mice

Abstract: ALS is a fatal paralytic disorder characterized by a progressive loss of spinal cord motor neurons. Herein, we show that NADPH oxidase, the main reactive oxygen species-producing enzyme during inflammation, is activated in spinal cords of ALS patients and in spinal cords in a genetic animal model of this disease. We demonstrate that inactivation of NADPH oxidase in ALS mice delays neurodegeneration and extends survival. We also show that NADPH oxidase-derived oxidant products damage proteins such as insulin-like growth factor 1 (IGF1) receptors, which are located on motor neurons. Our in vivo and in vitro data indicate that such an oxidative modification hinders the IGF1/Akt survival pathway in motor neurons. These findings suggest a non-cell-autonomous mechanism through which inflammation could hasten motor neuron death and contribute to the selective motor neuronal degeneration in ALS.

Neural mitochondrial Ca2+ capacity impairment precedes the onset of motor symptoms in G93A Cu/Zn-superoxide dismutase mutant mice.

Abstract: Mitochondrial respiratory chain dysfunction, impaired intracellular Ca2+ homeostasis and activation of the mitochondrial apoptotic pathway are pathological hallmarks in animal and cellular models of familial amyotrophic lateral sclerosis associated with Cu/Zn-superoxide dismutase mutations. Although intracellular Ca2+ homeostasis is thought to be intimately associated with mitochondrial functions, the temporal and causal correlation between mitochondrial Ca2+ uptake dysfunction and motor neuron death in familial amyotrophic lateral sclerosis remains to be established. We investigated mitochondrial Ca2+ handling in isolated brain, spinal cord and liver of mutant Cu/Zn-superoxide dismutase transgenic mice at different disease stages. In G93A mutant transgenic mice, we found a significant decrease in mitochondrial Ca2+ loading capacity in brain and spinal cord, as compared with age-matched controls, very early on in the course of the disease, long before the onset of motor weakness and massive neuronal death. Ca2+ loading capacity was not significantly changed in liver G93A mitochondria. We also confirmed Ca2+ capacity impairment in spinal cord mitochondria from a different line of mice expressing G85R mutant Cu/Zn-superoxide dismutase. In excitable cells, such as motor neurons, mitochondria play an important role in handling rapid cytosolic Ca2+ transients. Thus, mitochondrial dysfunction and Ca2+-mediated excitotoxicity are likely to be interconnected mechanisms that contribute to neuronal degeneration in familial amyotrophic lateral sclerosis.

Axonal damage markers in cerebrospinal fluid are increased in ALS.

Abstract: Objective: To test whether biomarkers for axonal degeneration correlated with clinical subtypes and were of use in predicting progression of ALS. Methods: Patients with ALS (n = 69), patients with Alzheimer disease (AD; n = 73), and age-matched controls (n = 33) were included in this prospective study. CSF levels of tau protein and neurofilaments (NfH SMI35 ) were measured using ELISA. In 49 patients with ALS, follow-up data were available (median follow-up 7 months). Results: CSF levels of NfH SMI35 were five times higher in patients with ALS (1.7 ng/mL) than in controls (0.3 ng/mL, p p SMI35 values were also higher in patients with upper motor neuron–dominant ALS than in patients with typical ALS (upper motor neuron + lower motor neuron) at p = 0.02. Values of NfH SMI35 were higher in ALS of more rapid progression. The values of NfH and tau did not correlate with CSF protein content. Conclusions: The authors propose that axonal damage markers in CSF may discriminate between subtypes of ALS and that they could be used as markers for therapeutic trials. CSF NfH was superior to tau in these discriminations.

Investigation of the therapeutic effects of edaravone, a free radical scavenger, on amyotrophic lateral sclerosis (Phase II study)

Abstract: Amyotrophic lateral sclerosis (ALS) is a rare disease involving selective and progressive degeneration and disappearance of motor neurons. Oxidative stress is believed to contribute to its pathogenesis. We have investigated the efficacy and safety of edaravone, a free radical scavenger previously approved for treatment of acute cerebral infarction, in ALS patients. Within an open trial design, 20 subjects with ALS received either 30 mg (5 subjects) or 60 mg (15 subjects) of edaravone via intravenous drip once per day. Two weeks of administration was followed by a two-week observation period. This four-week cycle was repeated six times. The primary endpoint was the change in the revised ALS functional rating scale (ALSFRS-R) score, while the secondary endpoint was 3-nitrotyrosine (3NT) level in cerebrospinal fluid (CSF). Efficacy was evaluated in the 60 mg group. During the six-month treatment period, the decline in the ALSFRS-R score (2.3+/-3.6 points) was significantly less than that in the six months prior to edaravone administration (4.7+/-2.1 points); the difference between the two was 2.4+/-3.5 points (Wilcoxon signed rank test, p = 0.039). In almost all patients, CSF 3NT, a marker for oxidative stress, was markedly reduced to almost undetectable levels at the end of the six-month treatment period. Data from the present study suggest that edaravone is safe and may delay the progression of functional motor disturbances by reducing oxidative stress in ALS patients.

Neuropathology with clinical correlations of sporadic amyotrophic lateral sclerosis: 102 autopsy cases examined between 1962 and 2000.

Abstract: Sporadic amyotrophic lateral sclerosis (ALS) is a fatal neurological disorder affecting adults. We studied the neuropathology and clinical correlations in 102 autopsy cases of ALS. The age at onset of the disease was significantly higher for the bulbaronset form (30 cases) than for the limb-onset form (72 cases). Dementia was confirmed in 7 cases. These 102 cases were divided into 4 pathological subgroups: typical ALS (59 cases), lower-motor-predominant ALS (23 cases), ALS with temporal lesions (18 cases), and ALS with pallido-nigro-luysian degeneration (2 cases). The age at onset was significantly higher for lower-motor-predominant ALS and ALS with temporal lesions than for typical ALS. In the lower motor neurons, Bunina bodies were detected in 88 cases, whereas ubiquitin-immunoreactive skein and/or spherical inclusions were detected in all 102 cases. Of the 100 available cases, 50 and 16 also showed ubiquitin-immunoreactive inclusions in the neostriatal and temporal small neurons, respectively. Ubiquitin-immunoreactive dystrophic neurites were also observed in the neostriatum in 3 of the 50 cases with neostriatal inclusions, and in the temporal cortex in 4 of the 16 cases with temporal inclusions. There was a significant association between the bulbar-onset form, temporal lesions, neostriatal inclusions and temporal inclusions, and between dementia, temporal lesions and temporal inclusions. Neostriatal and temporal dystrophic neurites were associated with dementia and bulbar-onset form through temporal lesions and temporal inclusions. The present findings may be helpful for designing further studies on the mechanisms underlying the development of ALS.

The CB2 cannabinoid agonist AM-1241 prolongs survival in a transgenic mouse model of amyotrophic lateral sclerosis when initiated at symptom onset

Abstract: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive motor neuron loss, paralysis and death within 2-5 years of diagnosis. Currently, no effective pharmacological agents exist for the treatment of this devastating disease. Neuroinflammation may accelerate the progression of ALS. Cannabinoids produce anti-inflammatory actions via cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2), and delay the progression of neuroinflammatory diseases. Additionally, CB2 receptors, which normally exist primarily in the periphery, are dramatically up-regulated in inflamed neural tissues associated with CNS disorders. In G93A-SOD1 mutant mice, the most well-characterized animal model of ALS, endogenous cannabinoids are elevated in spinal cords of symptomatic mice. Furthermore, treatment with non-selective cannabinoid partial agonists prior to, or upon, symptom appearance minimally delays disease onset and prolongs survival through undefined mechanisms. We demonstrate that mRNA, receptor binding and function of CB2, but not CB1, receptors are dramatically and selectively up-regulated in spinal cords of G93A-SOD1 mice in a temporal pattern paralleling disease progression. More importantly, daily injections of the selective CB2 agonist AM-1241, initiated at symptom onset, increase the survival interval after disease onset by 56%. Therefore, CB2 agonists may slow motor neuron degeneration and preserve motor function, and represent a novel therapeutic modality for treatment of ALS.

Thalidomide and Lenalidomide Extend Survival in a Transgenic Mouse Model of Amyotrophic Lateral Sclerosis

Abstract: Accumulating evidence suggests that inflammation plays a major role in the pathogenesis of motor neuron death in amyotrophic lateral sclerosis (ALS). Important mediators of inflammation such as the cytokine tumor necrosis factor-α (TNF-α) and its superfamily member fibroblast-associated cell-surface ligand (FasL) have been implicated in apoptosis. We found increased TNF-α and FasL immunoreactivity in lumbar spinal cord sections of ALS patients and G93A transgenic mice. Both increased TNF-α and FasL immunostaining in the lumbar spinal cord of the G93A SOD1 transgenic mice occurred at 40–60 d, well before the onset of symptoms and loss of motor neurons. We tested the neuroprotective effect of thalidomide and its analog lenalidomide, pharmacological agents that inhibit the expression of TNF-α and other cytokines by destabilizing their mRNA. Treatment with either thalidomide or lenalidomide attenuated weight loss, enhanced motor performance, decreased motor neuron cell death, and significantly increased the life span in G93A transgenic mice. Treated G93A mice showed a reduction in TNF-α and FasL immunoreactivity as well as their mRNA in the lumbar spinal cord. Both compounds also reduced interleukin (IL)-12p40, IL-1α, and IL-1β and increased IL-RA and TGF-β1 mRNA. Therefore, both thalidomide and lenalidomide bear promise as therapeutic interventions for the treatment of ALS.

Gene transfer demonstrates that muscle is not a primary target for non-cell-autonomous toxicity in familial amyotrophic lateral sclerosis.

Abstract: Amyotrophic lateral sclerosis (ALS) is a fatal, progressive paralysis arising from the premature death of motor neurons. An inherited form is caused by a dominant mutation in the ubiquitously expressed superoxide dismutase (SOD1). SOD1 mutant expression within motor neurons is a determinant of onset and early disease, and mutant accumulation within microglia accelerates disease progression. Muscle also is a likely primary source for toxicity, because retraction of motor axons from synaptic connections to muscle is among the earliest presymptomatic events. To test involvement of muscle in ALS, viral delivery of transcription-mediated siRNA is shown to suppress mutant SOD1 accumulation within muscle alone but to be insufficient to maintain grip strength, whereas delivery to both motor neurons and muscle is sufficient. Use of a deletable mutant gene to diminish mutant SOD1 from muscle did not affect onset or survival. Finally, follistatin expression encoded by adeno-associated virus chronically inhibited myostatin and produced sustained increases in muscle mass, myofiber number, and fiber diameter, but these increases did not affect survival. Thus, SOD1-mutant-mediated damage within muscles is not a significant contributor to non-cell-autonomous pathogenesis in ALS, and enhancing muscle mass and strength provides no benefit in slowing disease onset or progression.

On the relation of oxidative stress to neuroinflammation: lessons learned from the G93A-SOD1 mouse model of amyotrophic lateral sclerosis.

Abstract: The central nervous system (CNS) presents both challenges and opportunities to researchers of redox biochemistry. The CNS is sensitive to oxidative damage during aging or disease; excellent transgenic models of specific neurodegenerative diseases have been created that reproduce oxidative stress components of the corresponding human disorder. Mouse models of familial amyotrophic lateral sclerosis (ALS) based on overexpressed mutant human Cu,Zn-superoxide dismutase (SOD1) are cases in point. These animals experience predictably staged, age-dependent motor neuron degeneration with profound cellular and biochemical damage to nerve fibers and spinal cord tissue. Severe protein and lipid oxidation occurs in these animals, apparently as an indirect consequence of protein aggregation or cytopathic protein–protein interactions, as opposed to aberrant redox catalysis by the mutant enzyme. Recent studies of G93A-SOD1 mice and rats suggest that oxidative damage is part of an unmitigated neuroinflammatory reaction, p...

Widespread sensorimotor and frontal cortical atrophy in Amyotrophic Lateral Sclerosis

Abstract: Widespread cortical atrophy in Amyotrophic Lateral Sclerosis (ALS) has been described in neuropathological studies. The presence of cortical atrophy in conventional and scientific neuroimaging has been a matter of debate. In studies using computertomography, positron emission tomography, proton magnetic resonance spectroscopy and conventional T2-weighted and proton-weighted images, results have been variable. Recent morphometric studies by magnetic resonance imaging have produced conflicting results regarding the extent of grey and white matter involvement in ALS patients. The authors used optimized voxel-based morphometry as an unbiased whole brain approach to detect differences between regional grey and white matter volumes. Seventeen patients with a diagnosis of ALS according to El-Escorial criteria and seventeen age-matched controls received a high resolution anatomical T1 scan. In ALS patients regional grey matter volume (GMV) reductions were found in the pre- and postcentral gyrus bilaterally which extended to premotor, parietal and frontal regions bilaterally compared with controls (p < 0.05, corrected for the entire volume). The revised ALS functional rating scale showed a positive correlation with GMV reduction of the right medial frontal gyrus corresponding to the dorsolateral prefrontal cortex. No significant differences were found for white matter volumes or when grey and white matter density images were investigated. There were no further correlations with clinical variables found. In ALS patients, primary sensorimotor cortex atrophy can be regarded as a prominent feature of the disease. Supporting the concept of ALS being a multisytem disorder, our study provides further evidence for extramotor involvement which is widespread. The lack of correlation with common clinical variables probably reflects the fact that heterogeneous disease processes underlie ALS. The discrepancy within all published morphometric studies in ALS so far may be related to differences in patient cohorts and several methodological factors of the data analysis process. Longitudinal studies are required to further clarify the time course and distribution of grey and white matter pathology during the course of ALS.

An Observational Study of Cognitive Impairment in Amyotrophic Lateral Sclerosis

Abstract: Background Cognitive impairment is increasingly recognized in patients with amyotrophic lateral sclerosis (ALS). Clinical and pathologic features overlap in frontotemporal lobar dementia and ALS. Demographics, respiratory status, bulbar site of onset, and disease severity are potential risk factors for cognitive impairment in ALS. Objectives To further delineate the frequency, nature, and implications of cognitive impairment in ALS and to assess previously identified risk factors. Design Case-control and retrospective cohort study. Setting Academic referral center. Participants Forty consecutive patients with ALS underwent baseline neurologic and neuropsychologic examinations. Cognitive test performance was compared in patients with ALS and matched controls. An exploratory analysis of the relationship between cognitive performance and ALS survival was performed. Main Outcome Measures Neuropsychologic test performance, ALS severity, and survival. Results Twelve patients (30%) showed evidence of cognitive impairment, including 9 (23%) who met the neuropsychologic criteria for dementia. No statistically significant differences were found between demented and nondemented ALS groups regarding demographics, family history, site of onset, bulbar dysfunction, or ALS severity. Only 1 patient with dementia had bulbar-onset disease. An association was observed between increasing ALS severity and declining verbal fluency performance. Demented patients with ALS showed predominant impairment in free recall, executive function, and naming, with relative preservation of attention, psychomotor speed, and visuospatial function. No association was observed between cognition and survival, controlling for ALS severity. Conclusions Nearly a third of the patients with ALS showed evidence of cognitive impairment in a pattern consistent with frontotemporal lobar dementia. Cognitive performance was not related to site of onset or survival.

The neurite outgrowth inhibitor Nogo-A promotes denervation in an amyotrophic lateral sclerosis model

Abstract: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by motor neuron loss and muscle wasting. In muscles of ALS patients, Nogo-A—a protein known to inhibit axon regeneration—is ectopically expressed at levels that correlate with the severity of the clinical symptoms. We now show that the genetic ablation of Nogo-A extends survival and reduces muscle denervation in a mouse model of ALS. In turn, overexpression of Nogo-A in wild-type muscle fibres leads to shrinkage of the postsynapse and retraction of the presynaptic motor ending. This suggests that the expression of Nogo-A occurring early in ALS skeletal muscle could cause repulsion and destabilization of the motor nerve terminals, and subsequent dying back of the axons and motor neurons.

Human skeletal muscle atrophy in amyotrophic lateral sclerosis reveals a reduction in Akt and an increase in atrogin-1

Abstract: SPECIFIC AIMSThe molecular mechanisms influencing muscle atrophy in humans are poorly understood. Atrogin-1 and MuRF1, two ubiquitin E3-ligases, mediate muscle atrophy in rodents and cells and are ...