Informatics-assisted Protein Profiling in a Transgenic Mouse Model of Amyotrophic Lateral Sclerosis

Lukas, Thomas J.; Luo, Wei; Mao, Haihong; Cole, Natalie; Siddique, Teepu

doi:10.1074/mcp.m500431-mcp200

Cited by 36 publications

(33 citation statements)

References 72 publications

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“…In this report, we confirm that mitochondria from cells expressing mSOD1 have impaired ATP production, and this is associated with activation of the energy sensor AMPK. This observation is consistent with previous literature reporting dysregulation of various metabolic genes in mSOD1 models, including fatty acid synthase, fatty acid transporter (FAT/CD36), glucose transporter 4, p53, FOX03A, mTOR, and nitric oxide synthase, all of which are downstream targets of the AMPK pathway (Gonzalez de Aguilar et al, 2000;Martin, 2000;Lukas et al, 2006;Fergani et al, 2007;Lobsiger et al, 2007;Morimoto et al, 2007;Gonzalez de Aguilar et al, 2008;Martinez et al, 2008;Mojsilovic-Petrovic et al, 2009) (Lim and Kalb, unpublished observations). Furthermore, we show that AMPK activation has adverse effects on genetic models of motor neuron disease.…”

Section: Discussionsupporting

confidence: 82%

Reduced Activity of AMP-Activated Protein Kinase Protects against Genetic Models of Motor Neuron Disease

et al. 2012

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A growing body of research indicates that amyotrophic lateral sclerosis (ALS) patients and mouse models of ALS exhibit metabolic dysfunction. A subpopulation of ALS patients possesses higher levels of resting energy expenditure and lower fat-free mass compared to healthy controls. Similarly, two mutant copper zinc superoxide dismutase 1 (mSOD1) mouse models of familial ALS possess a hypermetabolic phenotype. The pathophysiological relevance of the bioenergetic defects observed in ALS remains largely elusive. AMPactivated protein kinase (AMPK) is a key sensor of cellular energy status and thus might be activated in various models of ALS. Here, we report that AMPK activity is increased in spinal cord cultures expressing mSOD1, as well as in spinal cord lysates from mSOD1 mice. Reducing AMPK activity either pharmacologically or genetically prevents mSOD1-induced motor neuron death in vitro. To investigate the role of AMPK in vivo, we used Caenorhabditis elegans models of motor neuron disease. C. elegans engineered to express human mSOD1 (G85R) in neurons develops locomotor dysfunction and severe fecundity defects when compared to transgenic worms expressing human wild-type SOD1. Genetic reduction of aak-2, the ortholog of the AMPK ␣2 catalytic subunit in nematodes, improved locomotor behavior and fecundity in G85R animals. Similar observations were made with nematodes engineered to express mutant tat-activating regulatory (TAR) DNA-binding protein of 43 kDa molecular weight. Altogether, these data suggest that bioenergetic abnormalities are likely to be pathophysiologically relevant to motor neuron disease.

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Section: Discussionsupporting

confidence: 82%

Reduced Activity of AMP-Activated Protein Kinase Protects against Genetic Models of Motor Neuron Disease

et al. 2012

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“…Decreased VDAC and cytochrome c oxidase subunits and increased adenylate kinase 2 seen here mirrored changes in wholespinal-cord extracts from a mutant SOD1 mouse (24). Decreased VDAC, aconitase, isocitrate dehydrogenase (IDH3), and ATP synthase subunits and increased NDUFB8, a component of the electron transport complex I (see below), were found, similar to changes seen in mitochondria from an ALS-linked SOD1 mutant expressing a motor neuron-like cell line (26).…”

Section: Altered Spinal Cord Mitochondrial Protein Content In Sod1 Mumentioning

confidence: 49%

“…Three prior efforts have reported use of proteomic tools to investigate how mutant SOD1 affects mitochondrial protein composition within whole-spinal-cord extracts of dismutase-active (24) or dismutase-inactive (25) SOD1 mutant mouse models or, more selectively, within mitochondria of a cell line retaining some motor neuron-like properties and expressing one dismutase-active, ALSlinked SOD1 mutant (26). We extended these approaches to determine whether mutant SOD1 affects protein content of spinal cord mitochondria before disease initiation in rodent models that develop ALS-like disease.…”

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confidence: 99%

ALS-linked mutant superoxide dismutase 1 (SOD1) alters mitochondrial protein composition and decreases protein import

Velde²,

Israelson³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

151

131

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Mutations in superoxide dismutase 1 (SOD1) cause familial ALS. Mutant SOD1 preferentially associates with the cytoplasmic face of mitochondria from spinal cords of rats and mice expressing SOD1 mutations. Two-dimensional gels and multidimensional liquid chromatography, in combination with tandem mass spectrometry, revealed 33 proteins that were increased and 21 proteins that were decreased in SOD1G93A rat spinal cord mitochondria compared with SOD1WT spinal cord mitochondria. Analysis of this group of proteins revealed a higher-than-expected proportion involved in complex I and protein import pathways. Direct import assays revealed a 30% decrease in protein import only in spinal cord mitochondria, despite an increase in the mitochondrial import components TOM20, TOM22, and TOM40. Recombinant SOD1 G93A or SOD1 G85R, but not SOD1WT or a Parkinson's disease-causing, misfolded α-synuclein E46K mutant, decreased protein import by >50% in nontransgenic mitochondria from spinal cord, but not from liver. Thus, altered mitochondrial protein content accompanied by selective decreases in protein import into spinal cord mitochondria comprises part of the mitochondrial damage arising from mutant SOD1.motor neuron disease | proteomic | neurodegenerative disease | amyotrophic A myotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder caused by loss of the motor neurons within the spinal cord and dysfunction of the motor pathways in the cortex (1, 2). Most cases of ALS (90%) are sporadic. Of the 10% of cases that are inherited, about one-fifth are caused by mutation within the superoxide dismutase 1 (SOD1) gene. Rodents expressing mutant SOD1 develop an ALS-like disease (1, 2). A consensus has emerged that disease arises from acquisition by the mutant proteins of one or more toxic properties, rather than from loss of dismutase activity (3, 4). At least eight prominent mutant-derived toxicities have been proposed, including mitochondrial dysfunction, excitotoxicity, endoplasmic reticulum stress, toxic extracellular SOD1, superoxide production from microglia or astrocytes, and disruption of the blood-brain barrier (5). Furthermore, pathogenesis is noncell autonomous with disease progression driven by mutant synthesis in astrocytes (6-8) and microglia (3, 9).Dysfunction of mitochondria can clearly cause specific damage to neurons or muscle because deletion/mutation in mitochondrial genes causes specific nerve and muscle diseases (10). Accompanying mutant SOD1-mediated disease in some mice is evidence for altered mitochondrial calcium-buffering capacity (11) and changes in the activity of complexes of the electron transport chain (12). Deletion of the mitochondrial BCL-2-related proteins BAX and BAK delays disease onset in SOD1 G93A mice (13), perhaps by modulating effects of SOD1 conformational changes to BCL-2 (14). Apparent damage to mitochondria has been reported in autopsy material from ALS patients (15, 16).Although SOD1 is a primarily cytosolic enzyme, wild-type SOD1 is also found in the intermembrane ...

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“…A few proteomics studies of spinal cord from the highly expressing G93A ALS transgenic mice have been published (34,35). Lukas et al (34) performed a study including nontransgenic mice and transgenic mice expressing wild-type human SOD1 (wthSOD1) mice as controls.…”

Section: Fig 6 Validationmentioning

confidence: 99%

Changes in the Spinal Cord Proteome of an Amyotrophic Lateral Sclerosis Murine Model Determined by Differential In-gel Electrophoresis

Bergemalm

Forsberg

Jonsson

et al. 2009

Molecular & Cellular Proteomics

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Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by loss of motor neurons resulting in progressive paralysis. To date, more than 140 different mutations in the gene encoding CuZn-superoxide dismutase (SOD1) have been associated with ALS. Several transgenic murine models exist in which various mutant SOD1s are expressed. We used DIGE to analyze the changes in the spinal cord proteome induced by expression of the unstable SOD1 truncation mutant G127insTGGG (G127X) in mice. Unlike mutants used in most other models, G127X lacks SOD activity and is present at low levels, thus reducing the risk of overexpression artifacts. The mice were analyzed at their peak body weights just before onset of symptoms. Variable importance plot analysis showed that 420 of 1,800 detected protein spots contributed significantly to the differences between the groups. By MALDI-TOF MS analysis, 54 differentially regulated proteins were identified. One spot was found to be a covalently linked mutant SOD1 dimer, apparently analogous to SOD1-immunoreactive bands migrating at double the molecular weight of SOD1 monomers previously detected in humans and mice carrying mutant SOD1s and in sporadic ALS cases. Analyses of affected functional pathways and the subcellular representation of alterations suggest that the toxicity exerted by mutant SODs induces oxidative stress and affects mitochondria, cellular assembly/organization, and protein degradation. Molecular & Cellular Proteomics 8: 1306 -1317, 2009. Amyotrophic lateral sclerosis (ALS)1 is a devastating neurodegenerative disease characterized by loss of motor neurons in the motor cortex, the brainstem, and the spinal cord. This results in progressive muscular atrophy, and the patients usually succumb to respiratory failure within a few years. About 10% of ALS cases are familial (1), and in some patients the disease is linked to mutations in the CuZn-superoxide dismutase (SOD1) gene (2). SOD1 is a ubiquitously expressed antioxidant enzyme. Overall about 6% of all cases with ALS show SOD1 mutations, and more than 140 such mutations have been identified (3). The mutations confer a cytotoxic gain of function of unknown character to the enzyme (4, 5). ALS caused by mutant SOD1s shows the same spectrum of disease phenotypes as is seen in sporadic cases lacking such mutations. This suggests that the pathogenesis of ALS induced by SOD1 mutations should show significant similarities with that in sporadic disease, e.g. similar pathogenic protein alterations.ALS has been modeled in mice via transgenic overexpression of mutant SOD1s (5-8). To cause disease within the short lifespan of a mouse, the mutant SOD1s have to be expressed at rates around 25-fold higher than the rate of expression of the endogenous murine enzyme (9). Mostly structurally stable mutants have been used, resulting in up to 10-fold increases in SOD activity and 20-fold increases in SOD1 protein levels in the CNS that may cause overexpression artifacts. Overloading of mitochondria with mutant SOD1s...

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Informatics-assisted Protein Profiling in a Transgenic Mouse Model of Amyotrophic Lateral Sclerosis

Cited by 36 publications

References 72 publications

Reduced Activity of AMP-Activated Protein Kinase Protects against Genetic Models of Motor Neuron Disease

Reduced Activity of AMP-Activated Protein Kinase Protects against Genetic Models of Motor Neuron Disease

ALS-linked mutant superoxide dismutase 1 (SOD1) alters mitochondrial protein composition and decreases protein import

Changes in the Spinal Cord Proteome of an Amyotrophic Lateral Sclerosis Murine Model Determined by Differential In-gel Electrophoresis

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