Vascular endothelial growth factor prevents G93A‐SOD1‐induced motor neuron degeneration

Amyotrophic lateral sclerosis (ALS) is an adult‐onset neurodegenerative disorder characterized by selective loss of motor neurons (MNs). Twenty percent of familial ALS cases are associated with mutations in Cu²⁺/Zn²⁺ superoxide dismutase (SOD1). To specifically understand the cellular mechanisms underlying mutant SOD1 toxicity, we have established an in vitro model of ALS using rat primary MN cultures transfected with an adenoviral vector encoding a mutant SOD1, G93A‐SOD1. Transfected cells undergo axonal degeneration and alterations in biochemical responses characteristic of cell death such as activation of caspase‐3. Vascular endothelial growth factor (VEGF) is an angiogenic and neuroprotective growth factor that can increase axonal outgrowth, block neuronal apoptosis, and promote neurogenesis. Decreased VEGF gene expression in mice results in a phenotype similar to that seen in patients with ALS, thus linking loss of VEGF to the pathogenesis of MN degeneration. Decreased neurotrophic signals prior to and during disease progression may increase MN susceptibility to mutant SOD1‐induced toxicity. In this study, we demonstrate a decrease in VEGF and VEGFR2 levels in the spinal cord of G93A‐SOD1 ALS mice. Furthermore, in isolated MN cultures, VEGF alleviates the effects of G93A‐SOD1 toxicity and neuroprotection involves phosphatidylinositol 3‐kinase/protein kinase B (PI3K/Akt) signaling. Overall, these studies validate the usefulness of VEGF as a potential therapeutic factor for the treatment of ALS and give valuable insight into the responsible signaling pathways and mechanisms involved. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009     

Exendin-4 ameliorates motor neuron degeneration in cellular and animal models of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by a progressive loss of lower motor neurons in the spinal cord. The incretin hormone, glucagon-like peptide-1 (GLP-1), facilitates insulin signaling, and the long acting GLP-1 receptor agonist exendin-4 (Ex-4) is currently used as an anti-diabetic drug. GLP-1 receptors are widely expressed in the brain and spinal cord, and our prior studies have shown that Ex-4 is neuroprotective in several neurodegenerative disease rodent models, including stroke, Parkinson's disease and Alzheimer's disease. Here we hypothesized that Ex-4 may provide neuroprotective activity in ALS, and hence characterized Ex-4 actions in both cell culture (NSC-19 neuroblastoma cells) and in vivo (SOD1 G93A mutant mice) models of ALS. Ex-4 proved to be neurotrophic in NSC-19 cells, elevating choline acetyltransferase (ChAT) activity, as well as neuroprotective, protecting cells from hydrogen peroxide-induced oxidative stress and staurosporine-induced apoptosis. Additionally, in both wild-type SOD1 and mutant SOD1 (G37R) stably transfected NSC-19 cell lines, Ex-4 protected against trophic factor withdrawal-induced toxicity. To assess in vivo translation, SOD1 mutant mice were administered vehicle or Ex-4 at 6-weeks of age onwards to end-stage disease via subcutaneous osmotic pump to provide steady-state infusion. ALS mice treated with Ex-4 showed improved glucose tolerance and normalization of behavior, as assessed by running wheel, compared to control ALS mice. Furthermore, Ex-4 treatment attenuated neuronal cell death in the lumbar spinal cord; immunohistochemical analysis demonstrated the rescue of neuronal markers, such as ChAT, associated with motor neurons. Together, our results suggest that GLP-1 receptor agonists warrant further evaluation to assess whether their neuroprotective potential is of therapeutic relevance in ALS.     

Inducible Nitric Oxide Synthase Up-Regulation in a Transgenic Mouse Model of Familial Amyotrophic Lateral Sclerosis

Mutations in copper/zinc superoxide dismutase (SOD1) are associated with a familial form of amyotrophic lateral sclerosis (ALS), and their expression in transgenic mice produces an ALS-like syndrome. Here we show that, during the course of the disease, the spinal cord of transgenic mice expressing mutant SOD1 (mSOD1) is the site not only of a progressive loss of motor neurons, but also of a dramatic gliosis characterized by reactive astrocytes and activated microglial cells. These changes are absent from the spinal cord of age-matched transgenic mice expressing normal SOD1 and of wild-type mice. We also demonstrate that, during the course of the disease, the expression of inducible nitric oxide synthase (iNOS) increases. In both early symptomatic and end-stage transgenic mSOD1 mice, numerous cells with the appearance of glial cells are strongly iNOS-immunoreactive. In addition, iNOS mRNA level and catalytic activity are increased significantly in the spinal cord of these transgenic mSOD1 mice. None of these alterations are seen in the cerebellum of these animals, a region unaffected by mSOD1. Similarly, no up-regulation of iNOS is detected in the spinal cord of age-matched transgenic mice expressing normal SOD1 or of wild-type mice. The time course of the spinal cord gliosis and iNOS up-regulation parallels that of motor neuronal loss in transgenic mSOD1 mice. Neuronal nitric oxide synthase expression is only seen in neurons in the spinal cord of transgenic mSOD1 mice, regardless of the stage of the disease, and of age-matched transgenic mice expressing normal SOD1 and wild-type mice. Collectively, these data suggest that the observed alterations do not initiate the death of motor neurons, but may contribute to the propagation of the neurodegenerative process. Furthermore, the up-regulation of iNOS, which in turn may stimulate the production of nitric oxide, provides further support to the presumed deleterious role of nitric oxide in the pathogenesis of ALS. This observation also suggests that iNOS may represent a valuable target for the development of new therapeutic avenues for ALS.     

Apelin deficiency accelerates the progression of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the selective loss of motor neurons. Recent studies have implicated that chronic hypoxia and insufficient vascular endothelial growth factor (VEGF)-dependent neuroprotection may lead to the degeneration of motor neurons in ALS. Expression of apelin, an endogenous ligand for the G protein-coupled receptor APJ, is regulated by hypoxia. In addition, recent reports suggest that apelin protects neurons against glutamate-induced excitotoxicity. Here, we examined whether apelin is an endogenous neuroprotective factor using SOD1(G93A) mouse model of ALS. In mouse CNS tissues, the highest expressions of both apelin and APJ mRNAs were detected in spinal cord. APJ immunoreactivity was observed in neuronal cell bodies located in gray matter of spinal cord. Although apelin mRNA expression in the spinal cord of wild-type mice was not changed from 4 to 18 weeks age, that of SOD1(G93A) mice was reduced along with the paralytic phenotype. In addition, double mutant apelin-deficient and SOD1(G93A) displayed the disease phenotypes earlier than SOD1(G93A) littermates. Immunohistochemical observation revealed that the number of motor neurons was decreased and microglia were activated in the spinal cord of the double mutant mice, indicating that apelin deficiency pathologically accelerated the progression of ALS. Furthermore, we showed that apelin enhanced the protective effect of VEGF on H(2)O(2)-induced neuronal death in primary neurons. These results suggest that apelin/APJ system in the spinal cord has a neuroprotective effect against the pathogenesis of ALS.     

DREAM-Dependent Activation of Astrocytes in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of unknown origin and characterized by a relentless loss of motor neurons that causes a progressive muscle weakness until death. Among the several pathogenic mechanisms that have been related to ALS, a dysregulation of calcium-buffering proteins in motor neurons of the brain and spinal cord can make these neurons more vulnerable to disease progression. Downstream regulatory element antagonist modulator (DREAM) is a neuronal calcium-binding protein that plays multiple roles in the nucleus and cytosol. The main aim of this study was focused on the characterization of DREAM and glial fibrillary acid protein (GFAP) in the brain and spinal cord tissues from transgenic SOD1^G93A mice and ALS patients to unravel its potential role under neurodegenerative conditions. The DREAM and GFAP levels in the spinal cord and different brain areas from transgenic SOD1^G93A mice and ALS patients were analyzed by Western blot and immunohistochemistry. Our findings suggest that the calcium-dependent excitotoxicity progressively enhanced in the CNS in ALS could modulate the multifunctional nature of DREAM, strengthening its apoptotic way of action in both motor neurons and astrocytes, which could act as an additional factor to increase neuronal damage. The direct crosstalk between astrocytes and motor neurons can become vulnerable under neurodegenerative conditions, and DREAM could act as an additional switch to enhance motor neuron loss. Together, these findings could pave the way to further study the molecular targets of DREAM to find novel therapeutic strategies to fight ALS.     

Overexpression of manganese superoxide dismutase attenuates neuronal death in human cells expressing mutant (G37R) Cu/Zn-superoxide dismutase

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by loss of motor function and eventual death as a result of degeneration of motor neurons in the spinal cord and brain. The discovery of mutations in SOD1, the gene encoding the antioxidant enzyme Cu/Zn-superoxide dismutase (CuZnSOD), in a subset of ALS patients has led to new insight into the pathophysiology of ALS. Utilizing a novel adenovirus gene delivery system, our laboratory has developed a human cell culture model using chemically differentiated neuroblastoma cells to investigate how mutations in SOD1 lead to neuronal death. Expression of mutant SOD1 (G37R) resulted in a time and dose-related death of differentiated neuroblastoma cells. This cell death was inhibited by overexpression of the antioxidant enzyme manganese superoxide dismutase (MnSOD). These observations support the hypothesis that mutant SOD1-associated neuronal death is associated with alterations in oxidative stress, and since MnSOD is a mitochondrial enzyme, suggest that mitochondria play a key role in disease pathogenesis. Our findings in this model of inhibition of mutant SOD1-associated death by MnSOD represent an unique approach to explore the underlying mechanisms of mutant SOD1 cytotoxicity and can be used to identify potential therapeutic agents for further testing.     

Human glial-restricted progenitor transplantation into cervical spinal cord of the SOD1 mouse model of ALS

Cellular abnormalities are not limited to motor neurons in amyotrophic lateral sclerosis (ALS). There are numerous observations of astrocyte dysfunction in both humans with ALS and in SOD1(G93A) rodents, a widely studied ALS model. The present study therapeutically targeted astrocyte replacement in this model via transplantation of human Glial-Restricted Progenitors (hGRPs), lineage-restricted progenitors derived from human fetal neural tissue. Our previous findings demonstrated that transplantation of rodent-derived GRPs into cervical spinal cord ventral gray matter (in order to target therapy to diaphragmatic function) resulted in therapeutic efficacy in the SOD1(G93A) rat. Those findings demonstrated the feasibility and efficacy of transplantation-based astrocyte replacement for ALS, and also show that targeted multi-segmental cell delivery to cervical spinal cord is a promising therapeutic strategy, particularly because of its relevance to addressing respiratory compromise associated with ALS. The present study investigated the safety and in vivo survival, distribution, differentiation, and potential efficacy of hGRPs in the SOD1(G93A) mouse. hGRP transplants robustly survived and migrated in both gray and white matter and differentiated into astrocytes in SOD1(G93A) mice spinal cord, despite ongoing disease progression. However, cervical spinal cord transplants did not result in motor neuron protection or any therapeutic benefits on functional outcome measures. This study provides an in vivo characterization of this glial progenitor cell and provides a foundation for understanding their capacity for survival, integration within host tissues, differentiation into glial subtypes, migration, and lack of toxicity or tumor formation.     

Human Motor Neurons Generated from Neural Stem Cells Delay Clinical Onset and Prolong Life in ALS Mouse Model

Amyotrophic lateral sclerosis (ALS) is the most common adult onset motor neuron disease. The etiology and pathogenic mechanisms of the disease remain unknown, and there is no effective treatment. Here we show that intrathecal transplantation of human motor neurons derived from neural stem cells (NSCs) in spinal cord of the SOD1G93A mouse ALS model delayed disease onset and extended life span of the animals. When HB1.F3.Olig2 (F3.Olig2) cells, stable immortalized human NSCs encoding the human Olig2 gene, were treated with sonic hedgehog (Shh) protein for 5–7 days, the cells expressed motor neuron cell type-specific phenotypes Hb9, Isl-1 and choline acetyltransferase (ChAT). These F3.Olig2-Shh human motor neurons were transplanted intrathecally in L5–L6 spinal cord of SOD1G93A mice, and at 4 weeks post-transplantation, transplanted F3.Olig2-Shh motor neurons expressing the neuronal phenotype markers NF, MAP2, Hb9, and ChAT were found in the ventral horn of the spinal cord. Onset of clinical signs in ALS mice with F3.Olig2-Shh motor neuron implants was delayed for 7 days and life span of animals was significantly extended by 20 days. Our results indicate that this treatment modality of intrathecal transplantation of human motor neurons derived from NSCs might be of value in the treatment of ALS patients without significant adverse effects.     

Amyotrophic lateral sclerosis-associated SOD1 mutant proteins bind and aggregate with Bcl-2 in spinal cord mitochondria

Familial amyotrophic lateral sclerosis (ALS)-linked mutations in the copper-zinc superoxide dismutase (SOD1) gene cause motor neuron death in about 3% of ALS cases. While the wild-type (wt) protein is anti-apoptotic, mutant SOD1 promotes apoptosis. We now demonstrate that both wt and mutant SOD1 bind the anti-apoptotic protein Bcl-2, providing evidence of a direct link between SOD1 and an apoptotic pathway. This interaction is evident in vitro and in vivo in mouse and human spinal cord. We also demonstrate that in mice and humans, Bcl-2 binds to high molecular weight SDS-resistant mutant SOD1 containing aggregates that are present in mitochondria from spinal cord but not liver. These findings provide new insights into the anti-apoptotic function of SOD1 and suggest that entrapment of Bcl-2 by large SOD1 aggregates may deplete motor neurons of this anti-apoptotic protein.     

Male-Specific Differences in Proliferation,Neurogenesis, and Sensitivity to Oxidative Stress in Neural Progenitor Cells Derived from a Rat Model of ALS

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive motor dysfunction and the loss of large motor neurons in the spinal cord and brain stem. A clear genetic link to point mutations in the superoxide dismutase 1 (SOD1) gene has been shown in a small group of familial ALS patients. The exact etiology of ALS is still uncertain, but males have consistently been shown to be at a higher risk for the disease than females. Here we present male-specific effects of the mutant SOD1 transgene on proliferation, neurogenesis, and sensitivity to oxidative stress in rat neural progenitor cells (rNPCs). E14 pups were bred using SOD1^G93A transgenic male rats and wild-type female rats. The spinal cord and cortex tissues were collected, genotyped by PCR using primers for the SOD1^G93A transgene or the male-specific Sry gene, and cultured as neurospheres. The number of dividing cells was higher in male rNPCs compared to female rNPCs. However, SOD1^G93A over-expression significantly reduced cell proliferation in male cells but not female cells. Similarly, male rNPCs produced more neurons compared to female rNPCs, but SOD1^G93A over-expression significantly reduced the number of neurons produced in male cells. Finally we asked whether sex and SOD1^G93A transgenes affected sensitivity to oxidative stress. There was no sex-based difference in cell viability after treatment with hydrogen peroxide or 3-morpholinosydnonimine, a free radical-generating agent. However, increased cytotoxicity by SOD1^G93A over-expression occurred, especially in male rNPCs. These results provide essential information on how the mutant SOD1 gene and sexual dimorphism are involved in ALS disease progression.     

Human Glial-Restricted Progenitor Transplantation into Cervical Spinal Cord of the SOD1G93A Mouse Model of ALS

Cellular abnormalities are not limited to motor neurons in amyotrophic lateral sclerosis (ALS). There are numerous observations of astrocyte dysfunction in both humans with ALS and in SOD1^G93A rodents, a widely studied ALS model. The present study therapeutically targeted astrocyte replacement in this model via transplantation of human Glial-Restricted Progenitors (hGRPs), lineage-restricted progenitors derived from human fetal neural tissue. Our previous findings demonstrated that transplantation of rodent-derived GRPs into cervical spinal cord ventral gray matter (in order to target therapy to diaphragmatic function) resulted in therapeutic efficacy in the SOD1^G93A rat. Those findings demonstrated the feasibility and efficacy of transplantation-based astrocyte replacement for ALS, and also show that targeted multi-segmental cell delivery to cervical spinal cord is a promising therapeutic strategy, particularly because of its relevance to addressing respiratory compromise associated with ALS. The present study investigated the safety and in vivo survival, distribution, differentiation, and potential efficacy of hGRPs in the SOD1^G93A mouse. hGRP transplants robustly survived and migrated in both gray and white matter and differentiated into astrocytes in SOD1^G93A mice spinal cord, despite ongoing disease progression. However, cervical spinal cord transplants did not result in motor neuron protection or any therapeutic benefits on functional outcome measures. This study provides an in vivo characterization of this glial progenitor cell and provides a foundation for understanding their capacity for survival, integration within host tissues, differentiation into glial subtypes, migration, and lack of toxicity or tumor formation.     

Early decrease of survival signal-related proteins in spinal motor neurons of presymptomatic transgenic mice with a mutant SOD1 gene

The mechanisms of motor neuronal death in amyotrophic lateral sclerosis (ALS) remain to be unclear. Phosphatidy-linositol 3-kinase (PI3-K) and its main downstream effector, Akt/protein kinase B (PKB) have been shown to play a central role in neuronal survival against apoptosis supported by neurotrophic factors. In order to investigate a possible impairment of survival signaling, we examined expressions of PI3-K and Akt in the spinal cord of the transgenic mice overexpressing a mutant Cu/Zn superoxide dismutase (SOD1) gene, a valuable model for human ALS. Immunoblotting and immunohistochemical analyses showed that the majority of spinal motor neurons lost the immunoreactivities for both PI3-K and Akt in the early and presymptomatic stage that preceded significant loss of the neurons. The present results suggest that an early decrease of survival signal proteins in the spinal motor neurons may account for the subsequent motor neuronal loss in this animal model of ALS.     

Mitochondria-Targeted Catalase Reverts the Neurotoxicity of hSOD1G93A Astrocytes without Extending the Survival of ALS-Linked Mutant hSOD1 Mice

Dominant mutations in the Cu/Zn-superoxide dismutase (SOD1) cause familial forms of amyotrophic lateral sclerosis (ALS), a fatal disorder characterized by the progressive loss of motor neurons. The molecular mechanism underlying the toxic gain-of-function of mutant hSOD1s remains uncertain. Several lines of evidence suggest that toxicity to motor neurons requires damage to non-neuronal cells. In line with this observation, primary astrocytes isolated from mutant hSOD1 over-expressing rodents induce motor neuron death in co-culture. Mitochondrial alterations have been documented in both neuronal and glial cells from ALS patients as well as in ALS-animal models. In addition, mitochondrial dysfunction and increased oxidative stress have been linked to the toxicity of mutant hSOD1 in astrocytes and neurons. In mutant SOD1-linked ALS, mitochondrial alterations may be partially due to the increased association of mutant SOD1 with the outer membrane and intermembrane space of the mitochondria, where it can affect several critical aspects of mitochondrial function. We have previously shown that decreasing glutathione levels, which is crucial for peroxide detoxification in the mitochondria, significantly accelerates motor neuron death in hSOD1^G93A mice. Here we employed a catalase targeted to the mitochondria to investigate the effect of increased mitochondrial peroxide detoxification capacity in models of mutant hSOD1-mediated motor neuron death. The over-expression of mitochondria-targeted catalase improved mitochondrial antioxidant defenses and mitochondrial function in hSOD1^G93A astrocyte cultures. It also reverted the toxicity of hSOD1^G93A-expressing astrocytes towards co-cultured motor neurons, however ALS-animals did not develop the disease later or survive longer. Hence, while increased oxidative stress and mitochondrial dysfunction have been extensively documented in ALS, these results suggest that preventing peroxide-mediated mitochondrial damage alone is not sufficient to delay the disease.     

Characterizing the multiple roles of FGF-2 in SOD1G93A ALS mice in vivo and in vitro

We have previously shown that knockout of fibroblast growth factor-2 (FGF-2) and potential compensatory effects of other growth factors result in amelioration of disease symptoms in a transgenic mouse model of amyotrophic lateral sclerosis (ALS). ALS is a rapidly progressive neurological disorder leading to degeneration of cortical, brain stem, and spinal motor neurons followed by subsequent denervation and muscle wasting. Mutations in the superoxide dismutase 1 (SOD1) gene are responsible for approximately 20% of familial ALS cases and SOD1 mutant mice still are among the models best mimicking clinical and neuropathological characteristics of ALS. The aim of the present study was a thorough characterization of FGF-2 and other growth factors and signaling effectors in vivo in the SOD1^G93A mouse model. We observed tissue-specific opposing gene regulation of FGF-2 and overall dysregulation of other growth factors, which in the gastrocnemius muscle was associated with reduced downstream extracellular-signal-regulated kinases (ERK) and protein kinase B (AKT) activation. To further investigate whether the effects of FGF-2 on motor neuron death are mediated by glial cells, astrocytes lacking FGF-2 were cocultured together with mutant SOD1 ^G93A motor neurons. FGF-2 had an impact on motor neuron maturation indicating that astrocytic FGF-2 affects motor neurons at a developmental stage. Moreover, neuronal gene expression patterns showed FGF-2- and SOD1 ^G93A-dependent changes in ciliary neurotrophic factor, glial-cell-line-derived neurotrophic factor, and ERK2, implying a potential involvement in ALS pathogenesis before the onset of clinical symptoms.     

Proteasomal inhibition by misfolded mutant superoxide dismutase 1 induces selective motor neuron death in familial amyotrophic lateral sclerosis

Accumulating evidence indicates that abnormal conformation of mutant superoxide dismutase 1 (SOD1) is an essential feature underlying the pathogenesis of mutant SOD1-linked familial amyotrophic lateral sclerosis (ALS). Here we investigated the role of ubiquitin-proteasome pathway in the mutant SOD1-related cell death and the effect of oxidative stress on the misfolding of mutant SOD1. Transient overexpression of ubiquitin with human SOD1 (wild-type, ala4val, gly85arg, gly93ala) in Neuro2A cells decreased the amount of mutant SOD1, but not of wild-type, while only mutants were co-immunoprecipitated with poly-ubiquitin. Proteasome inhibition by lactacystin augmented accumulation of mutant SOD1 in the non-ionic detergent-insoluble fraction. The spinal cord lysates from mutant SOD1 transgenic mice showed multiple carbonylated proteins, including mutant SOD1 with SDS-resistant dimer formation. Furthermore, the treatment of hSOD1-expressing cells with hydrogen peroxide promoted the oligomerization, and detergent-insolubility of mutant SOD1 alone, and the oxidized mutant SOD1 proteins were more heavily poly-ubiquitinated. In Neuro2A cells stably expressing human SOD1 protein, the proteasome function measured by chymotrypsin-like activity, was decreased over time without a quantitative alteration of the 20S proteasomal component. Finally, primary motor neurons from the mouse embryonic spinal cord were more vulnerable to lactacystin than non-motor neurons. These results indicate that the sustained expression of mutant SOD1 leads to proteasomal inhibition and motor neuronal death, which in part explains the pathogenesis of mutant SOD1-linked ALS.     

Muscle expression of a local Igf-1 isoform protects motor neurons in an ALS mouse model

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by a selective degeneration of motor neurons, atrophy, and paralysis of skeletal muscle. Although a significant proportion of familial ALS results from a toxic gain of function associated with dominant SOD1 mutations, the etiology of the disease and its specific cellular origins have remained difficult to define. Here, we show that muscle-restricted expression of a localized insulin-like growth factor (Igf) -1 isoform maintained muscle integrity and enhanced satellite cell activity in SOD1(G93A) transgenic mice, inducing calcineurin-mediated regenerative pathways. Muscle-specific expression of local Igf-1 (mIgf-1) isoform also stabilized neuromuscular junctions, reduced inflammation in the spinal cord, and enhanced motor neuronal survival in SOD1(G93A) mice, delaying the onset and progression of the disease. These studies establish skeletal muscle as a primary target for the dominant action of inherited SOD1 mutation and suggest that muscle fibers provide appropriate factors, such as mIgf-1, for neuron survival.     

DJ-1 Knockout Augments Disease Severity and Shortens Survival in a Mouse Model of ALS

Amyotrophic lateral sclerosis (ALS) is a progressive, lethal, neurodegenerative disorder, characterized by the degeneration of motor neurons. Oxidative stress plays a central role in the disease progression, in concert with an enhanced glutamate excitotoxicity and neuroinflammation. DJ-1 mutations, leading to the loss of functional protein, cause familial Parkinson’s disease and motor neuron disease in several patients. DJ-1 responds to oxidative stress and plays an important role in the cellular defense mechanisms. We aimed to investigate whether loss of functional DJ-1 alters the disease course and severity in an ALS mouse model. To this end we used mice that express the human SOD1^G93A mutation, the commonly used model of ALS and knockout of DJ-1 mice to generate SOD1 DJ-1 KO mice. We found that knocking out DJ-1in the ALS model led to an accelerated disease course and shortened survival time. DJ-1 deficiency was found to increase neuronal loss in the spinal cord associated with increased gliosis in the spinal cord and reduced antioxidant response that was regulated by the Nrf2 mechanism.The importance of DJ-1 in ALS was also illustrated in a motor neuron cell line that was exposed to glutamate toxicity and oxidative stress. Addition of the DJ-1 derived peptide, ND-13, enhanced the resistance to glutamate and SIN-1 induced toxicity. Thus, our results maintain that DJ-1 plays a role in the disease process and promotes the necessity of further investigation of DJ-1 as a therapeutic target for ALS.     

A specific inhibitor of janus kinase-3 increases survival in a transgenic mouse model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive, fatal neurodegenerative disorder involving the motor neurons of cortex, brain stem, and spinal cord. About 10% of all ALS patients are familial cases (FALS), of which 20% have mutations in the Cu, Zn-superoxide dismutase (SOD1) gene. The murine model for FALS, which overexpresses a FALS variant of the SOD1 gene, exhibits progressive limbic paralysis followed by death. Treatment of FALS mice with WHI-P131, a specific inhibitor of Janus kinase 3 (JAK3), increased survival by more than two months, suggesting that specific inhibitors of JAK3 may be useful in the treatment of human ALS. These results uniquely establish JAK3 as a novel molecular target for the treatment of FALS.