Nuclear localization of human SOD1 and mutant SOD1-specific disruption of survival motor neuron protein complex in transgenic amyotrophic lateral sclerosis mice

Amyotrophic lateral sclerosis (ALS) is a fatal adult-onset neurodegenerative disease that causes degeneration of motor neurons and paralysis. Approximately 20% of familial ALS cases have been linked to mutations in the copper/zinc superoxide dismutase (SOD1) gene, but it is unclear how mutations in the protein result in motor neuron degeneration. Transgenic (tg) mice expressing mutated forms of human SOD1 (hSOD1) develop clinical and pathological features similar to those of ALS. We used tg mice expressing hSOD1-G93A, hSOD1-G37R, and hSOD1-wild-type to investigate a new subcellular pathology involving mutant hSOD1 protein prominently localizing to the nuclear compartment and disruption of the architecture of nuclear gems. We developed methods for extracting relatively pure cell nucleus fractions from mouse CNS tissues and demonstrate a low nuclear presence of endogenous SOD1 in mouse brain and spinal cord, but prominent nuclear accumulation of hSOD1-G93A, -G37R, and -wild-type in tg mice. The hSOD1 concentrated in the nuclei of spinal cord cells, particularly motor neurons, at a young age. The survival motor neuron protein (SMN) complex is disrupted in motor neuron nuclei before disease onset in hSOD1-G93A and -G37R mice; age-matched hSOD1-wild-type mice did not show SMN disruption despite a nuclear presence. Our data suggest new mechanisms involving hSOD1 accumulation in the cell nucleus and mutant hSOD1-specific perturbations in SMN localization with disruption of the nuclear SMN complex in ALS mice and suggest an overlap of pathogenic mechanisms with spinal muscular atrophy.     

内质网应激因子ATF6在hSOD1~(G93A)转基因小鼠脊髓中的表达

目的应用目前国际公认的肌萎缩侧索硬化(ALS)发病机制及临床前药物研究的动物模型hSOD1~(G93A)转基因小鼠,初步研究hSOD1~(G93A)小鼠脊髓中是否存在内质网应激中活性转录激活因子(ATF6)信号通路的激活,进而探究内质网应激在ALS发病机制中的作用。方法①hSOD1~(G93A)转基因小鼠及其同窝对照组小鼠的获得;②应用免疫组织化学方法观察转基因小鼠组和对照组显示脊髓前角运动神经元ATF6阳性细胞数量。结果症状早期和终末期转基因小鼠(分别为105~115d和120~130d),较对照组和无症状组转基因小鼠(60d)ATF6进入细胞核的运动神经元数量明显增多,差异有统计学意义(P0.05);症状早期和终末期相比较差异无统计学意义(P0.05);症状早期和终末期的一些细胞形态发生改变,出现皱缩,终末期运动神经元的数目减少。结论在无症状组时没有发现内质网应激因子ATF6的改变,但在疾病症状早期出现明显ATF6的改变,并随着疾病的进展而加重,说明内质网应激参与了ALS的发病,同时终末期脊髓前角运动神经元数量大幅减少。     

PICK1 expression in reactive astrocytes within the spinal cord of amyotrophic lateral sclerosis (ALS) rats

M. C. Focant, S. Goursaud, C. Boucherie, A. O. Dumont and E. Hermans (2013) Neuropathology and Applied Neurobiology 39, 231–242 PICK1 expression in reactive astrocytes within the spinal cord of amyotrophic lateral sclerosis (ALS) rats Aims: The protein interacting with C kinase 1 (PICK1), a PDZ domain‐containing protein mainly expressed in the central nervous system, interacts with the glutamate receptor subunit GluR2, with the glutamate transporter GLT‐1b and with the enzyme serine racemase. These three proteins appear as key actors in the glutamate‐mediated excitotoxicity associated with amyotrophic lateral sclerosis (ALS), in both patients and animal models of the disease. In this study, we examined the expression of PICK1 in the spinal cord of transgenic rats expressing a mutated form of the human superoxide dismutase 1 (hSOD1^G93A) during the progression of the disease. Methods: Expression of PICK1 was examined by real‐time qPCR at presymptomatic and symptomatic stages as well as at end‐stage. The expression of PICK1 in the different cell types of the spinal cord was examined by immunohistochemistry. Results: The overall expression of PICK1 is not modified in cervical and lumbar spinal cord of transgenic (hSOD1^G93A) rats during the progression of the disease. Nonetheless, immunohistochemical studies of lumbar ventral horns revealed a shift of PICK1 expression from motor neurones in healthy rats to activated astrocytes in end‐stage hSOD1^G93A animals. Conclusions: Considering the documented influence of PICK1 expression on d ‐serine release and glutamate transport in astrocytes, these findings point to a potential implication of PICK1 in the progression of ALS.     

Expression of the ALS-causing variant hSOD1G93A leads to an impaired integrity and altered regulation of claudin-5 expression in an in vitro blood–spinal cord barrier model

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive paralysis due to the loss of primary and secondary motor neurons. Mutations in the Cu/Zn-superoxide dismutase (SOD1) gene are associated with familial ALS and to date numerous hypotheses for ALS pathology exist including impairment of the blood–spinal cord barrier. In transgenic mice carrying mutated SOD1 genes, a disrupted blood–spinal cord barrier as well as decreased levels of tight junction (TJ) proteins ZO-1, occludin, and claudin-5 were detected. Here, we examined TJ protein levels and barrier function of primary blood–spinal cord barrier endothelial cells of presymptomatic hSOD1^G93A mice and bEnd.3 cells stably expressing hSOD1^G93A. In both cellular systems, we observed reduced claudin-5 levels and a decreased transendothelial resistance (TER) as well as an increased apparent permeability. Analysis of the β-catenin/AKT/forkhead box protein O1 (FoxO1) pathway and the FoxO1-regulated activity of the claudin-5 promoter revealed a repression of the claudin-5 gene expression in hSOD1^G93A cells, which was depended on the phosphorylation status of FoxO1. These results strongly indicate that mutated SOD1 affects the expression and localization of TJ proteins leading to impaired integrity and breakdown of the blood–spinal cord barrier.     

Intraspinal cord delivery of IGF-I mediated by adeno-associated virus 2 is neuroprotective in a rat model of familial ALS

BackgroundAmyotrophic lateral sclerosis (ALS) is a devastating disease that is characterized by the progressive loss of motor neurons. Patients with ALS usually die from respiratory failure due to respiratory muscle paralysis. Consequently, therapies aimed at preserving segmental function of the respiratory motor neurons could extend life for these patients. Insulin-like growth factor-I (IGF-I) is known to be a potent survival factor for motor neurons. In this study we induced high levels of IGF-I expression in the cervical spinal cord of hSOD1^G93A rats with intraspinal cord (ISC) injections of an adeno-associated virus serotype 2 vector (CERE-130). This approach reduced the extent of motor neuron loss in the treated segments of the spinal cord. However, a corresponding preservation of motor function was observed in male, but not female, hSOD1^G93A rats. We conclude that ISC injection of CERE-130 has the potential to protect motor neurons and preserve neuromuscular function in ALS.     

Oxidative stress and antioxidant enzyme upregulation in SOD1-G93A mouse skeletal muscle

Amyotrophic lateral sclerosis (ALS) is caused by motor neuron loss in the spinal cord, but the mechanisms responsible are not known. Ubiquitous transgenic overexpression of copper/zinc superoxide dismutase (SOD1) mutations causing familial ALS (SOD1mut) leads to an ALS phenotype in mice; however, restricted expression of SOD1mut in neurons alone is not sufficient to cause this phenotype, suggesting that non-neuronal SOD1mut expression is also required for disease manifestation. Recently, several investigators have suggested that SOD1mut -mediated oxidative stress in skeletal muscle may contribute to ALS pathogenesis. The purpose of this study was to examine oxidative stress and antioxidant enzyme adaptation in 95-day-old SOD1-G93A skeletal muscle. We observed significant elevations in both malondialdehyde (22% and 31% in red and white gastrocnemius, respectively) and protein carbonyls (53% in red gastrocnemius) in SOD1-G93A mice. Copper/zinc SOD activity was higher in red and white SOD1-G93A gastrocnemius (7- and 10-fold, respectively), as was manganese SOD (4- and 5-fold, respectively) and catalase (2- and 2.5-fold, respectively). Taken together, our data demonstrate oxidative stress and compensatory antioxidant enzyme upregulation in SOD1-G93A skeletal muscle.     

小胶质细胞在SOD1-G93A转基因小鼠腰髓中的变化

目的观察小胶质细胞在SOD1-G93A转基因小鼠不同时期腰髓中的变化,探讨小胶质细胞活化与肌萎缩侧索硬化(ALS)疾病进展的关系。方法以国际公认的SOD1-G93A转基因小鼠,应用免疫组化、激光共聚焦显微镜及Westernblot方法 ,分别观察SOD1-G93A转基因小鼠症状前期、症状期、终末期及其同窝对照腰髓小胶质细胞形态数量及特异性标记物表达的变化情况。结果 SOD1-G93A转基因小鼠腰髓在症状前期(60天)已出现小胶质细胞数量增多及特异性标记物CD11b表达升高,随病程进展,症状期小胶质细胞增多、活化显著,终末期达高峰。结论随SOD1-G93A转基因小鼠病程进展小胶质细胞增生明显,小胶质细胞的活化可能参与ALS运动神经元损伤。     

Calpain activation and CaMKIV reduction in spinal cords from hSOD1G93A mouse model

Amyotrophic Lateral Sclerosis (ALS), a severe neurodegenerative disease, affects the upper and lower motor neurons in the brain and spinal cord. In some studies, ALS disease progression has been associated with an increase in calcium-dependent degeneration processes. Motoneurons are specifically vulnerable to sustained membrane depolarization and excessive elevation of intracellular calcium concentration. The present study analyzed intracellular events in embryonic motoneurons and adult spinal cords of the hSOD1G93A ALS mouse model. We observed activation of calpain, a calcium-dependent cysteine protease that degrades a variety of substrates, and a reduction in calcium–calmodulin dependent protein kinase type IV (CaMKIV) levels in protein extracts from spinal cords obtained at several time-points of hSOD1G93A mice disease progression. However, in cultured embryonic motoneurons these differences between controls and hSOD1G93A mutants are not evident. Our results support the hypothesis that age-dependent changes in calcium homeostasis and resulting events, e.g., calpain activation and CaMKIV processing, are involved in ALS pathogenesis.     

Increased expression of connective tissue growth factor in amyotrophic lateral sclerosis human spinal cord

Connective tissue growth factor (CTGF) is a secreted protein involved in a variety of cellular events such as survival, proliferation, and extracellular matrix production. Recent studies suggest a role for this protein also in the repair processes of the central nervous system. The distribution and significance of CTGF in human brain is, however, poorly understood, particularly under pathological conditions. In the present study the expression of CTGF protein was investigated in the spinal cord of control and both sporadic and familial amyotrophic lateral sclerosis (sALS and fALS) patients. Western blot analysis showed a consistent increase in CTGF expression in six sALS patients compared with controls. Immunoreactivity signal for CTGF was equally present in blood vessels of control and ALS spinal cord, but was dramatically increased in reactive astrocytes of the ventral horn and white matter in both sALS and fALS. Increased expression was also observed in the cytoplasm of motor neurons of sALS and fALS patients with long duration of the disease. Our data indicate a role for CTGF in the complex reactive process that is associated with the progression of ALS spinal cord damage. The up-regulation in reactive astrocytes supports a role for CTGF in the molecular mechanisms underlying astrogliosis. However, the altered CTGF expression observed in neurons might represent an additional mechanism involved in motor neuron dysfunction and changes in glial-neuronal communication in the course of the neurodegenerative process.The first two authors contributed equally to the present work.     

Relationship of oxygen radical-induced lipid peroxidative damage to disease onset and progression in a transgenic model of familial ALS

Transgenic mice that overexpress a mutated human CuZn superoxide dismutase (SOD1) gene (gly⁹³→ala) found in some patients with familial ALS (FALS) have been shown to develop motor neuron disease, as evidenced by motor neuron loss in the lumbar and cervical spinal regions and a progressive loss of voluntary motor activity. The mutant Cu,Zn SOD exhibits essentially normal dismutase activity, but in addition, generates toxic oxygen radicals as a result of an enhancement of a normally minor peroxidase reaction. In view of the likelihood that the manifestation of motor neuron disease in the FALS transgenic mice involves an oxidative injury mechanism, the present study sought to examine the extent of lipid peroxidative damage in the spinal cords of the TgN(SOD1-G93A)G1H mice over their life span compared to nontransgenic littermates or transgenic mice that overexpress the wild-type human Cu,Zn SOD (TgN(SOD1)N29). Lipid peroxidation was investigated in terms of changes in vitamin E and malondialdehyde (MDA) levels measured by HPLC methods and by MDA-protein adduct immunoreactivity. Four ages were investigated: 30 days (pre-motor neuron pathology and clinical disease); 60 days (after initiation of pathology, but predisease); 100 days (approximately 50% loss of motor neurons and function); and 120 days (near complete hindlimb paralysis). Compared to nontransgenic mice, the TgN(SOD1-G93A)G1H mice showed blunted accumulation of spinal cord vitamin E and higher levels of MDA (P < 0.05 at 30 and 60 days) over the 30–120 day time span. In the TgN(SOD1)N29 mice, levels of MDA at age 120 days were significantly lower than in either the TgN(SOD1-G93A)G1H or nontransgenic mice. MDA-protein adduct immunoreactivity was also significantly increased in the lumbar spinal cord at age 30, 100, and 120 days, and in the cervical cord at 100 and 120 days. The results clearly demonstrate an increase in spinal cord lipid peroxidation in the FALS transgenic model, which precedes the onset of ultrastructural or clinical motor neuron disease. However, the greatest intensity of actual motor neuronal lipid peroxidative injury is associated with the active phase of disease progression. These findings further support a role of oxygen radical-mediated motor neuronal injury in the pathogenesis of FALS and the potential benefits of antioxidant therapy. J. Neurosci. Res. 53:66–77, 1998. © 1998 Wiley-Liss, Inc.     

PARP expression is increased in astrocytes but decreased in motor neurons in the spinal cord of sporadic ALS patients

The evidence for increased oxidative stress and DNA damage in amyotrophic lateral sclerosis (ALS) prompted studies to determine if the expression of poly(ADP-ribose) polymerase (PARP) is increased in ALS. Using Western analyses of postmortem tissue, we demonstrated that PARP-immunoreactivity (PARP-IR) was increased 3-fold in spinal cord tissues of sporadic ALS (sALS) patients compared with non-neurological disease controls. Despite the increased PARP-IR, PARP mRNA expression was not increased significantly. Immunohistochemical analyses revealed PARP-IR was increased in both white and gray matter of sALS spinal cord. While PARP-IR was predominantly seen in astrocytes, large motor neurons displayed reduced staining compared with controls. This result contrasts sharply to the staining of Alzheimer and MPTP-induced Parkinson diseased tissue, where poly(ADP-ribose) (PAR)-IR was seen mostly in neurons, with little astrocytic staining. PARP-IR was increased in the pellet fraction of sALS homogenates compared with control homogenates, representing potential PARP binding to chromatin or membranes and suggesting a possible mechanism of PARP stabilization. The present results demonstrate glial alterations in sALS spinal cord tissue and support the role of glial alterations in sALS pathogenesis. Additionally, these results demonstrate differences in sALS spinal motor neurons and astrocytes compared to brain neurons and astrocytes in Alzheimer disease and MPTP-induced Parkinson disease despite the presence of markers for oxidative stress in all 3 diseases.     

14-3-3 proteins in Lewy body-like hyaline inclusions in patients with sporadic amyotrophic lateral sclerosis

14-3-3 proteins are highly conserved eukaryotic proteins that regulate various types of signal transduction pathways through phosphorylation-dependent protein-protein interactions. 14-3-3 mRNAs have been shown to be up-regulated in the injured rat motor neurons and in the spinal cords of patients with amyotrophic lateral sclerosis (ALS). To investigate the role of 14-3-3 proteins in ALS, we performed immunohistochemical studies on 14-3-3 using autopsied spinal cords from patients with sporadic ALS (sALS) and non-ALS subjects without spinal cord involvement. In the anterior horn of both groups, strong 14-3-3 immunoreactivity was observed in the somata and proximal processes of motor neurons. Many spheroids from all of the sALS cases were also immunopositive for 14-3-3. In addition, Lewy body-like hyaline inclusions (LBHIs), which were present in some sALS cases, were intensely immunostained. Our findings suggest that even in the severely affected anterior horn of patients with sALS, remaining motor neurons may contain abundant 14-3-3 proteins, and that 14-3-3 proteins may be partly associated with the pathogenesis of sALS, in particular with the formation of LBHIs.     

Human Cu/Zn Superoxide Dismutase (SOD1) Overexpression in Mice Causes Mitochondrial Vacuolization, Axonal Degeneration, and Premature Motoneuron Death and Accelerates Motoneuron Disease in Mice Expressing a Familial Amyotrophic Lateral Sclerosis Mutant SOD1

Cytosolic Cu/Zn superoxide dismutase (SOD1) is a ubiquitous small cytosolic metalloenzyme that catalyzes the conversion of superoxide anion to hydrogen peroxide (H₂O₂). Mutations in the SOD1 gene cause a familial form of amyotrophic lateral sclerosis (fALS). The mechanism by which mutant SOD1s causes ALS is not understood. Transgenic mice expressing multiple copies of fALS-mutant SOD1s develop an ALS-like motoneuron disease resembling ALS. Here we report that transgenic mice expressing a high concentration of wild-type human SOD1 (hSOD1_WT) develop an array of neurodegenerative changes consisting of (1) swelling and vacuolization of mitochondria, predominantly in axons in the spinal cord, brain stem, and subiculum; (2) axonal degeneration in a number of long fiber tracts, predominantly the spinocerebellar tracts; and (3) at 2 years of age, a moderate loss of spinal motoneurons. Parallel to the development of neurodegenerative changes, hSOD1_WT mice also develop mild motor abnormalities. Interestingly, mitochondrial vacuolization was associated with accumulation of hSOD1 immunoreactivity, suggesting that the development of mitochondrial pathology is associated with disturbed SOD1 turnover. In this study we also crossed hSOD1_WT mice with a line of fALS-mutant SOD1 mice (hSOD1_G93A) to generate “double” transgenic mice that express high levels of both wild-type and G93A mutant hSOD1. The “double” transgenic mice show accelerated motoneuron death, earlier onset of paresis, and earlier death as compared with hSOD1_G93A littermates. Thus in vivo expression of high levels of wild-type hSOD1 is not only harmful to neurons in itself, but also increases or facilitates the deleterious action of a fALS-mutant SOD1. Our data indicate that it is important for motoneurons to control the SOD1 concentration throughout their processes, and that events that lead to improper synthesis, transport, or breakdown of SOD1 causing its accumulation are potentially dangerous.     

Discrete mitochondrial aberrations in the spinal cord of sporadic ALS patients

Amyotrophic lateral sclerosis (ALS) is an adult onset neurodegenerative disease characterized by progressive motor neuron degeneration in the brain and spinal cord leading to muscle atrophy, paralysis, and death. Mitochondrial dysfunction is a major contributor to motor neuron degeneration associated with ALS progression. Mitochondrial abnormalities have been determined in spinal cords of animal disease models and ALS patients. However, molecular mechanisms leading to mitochondrial dysfunction in sporadic ALS (sALS) patients remain unclear. Also, segmental or regional variation in mitochondrial activity in the spinal cord has not been extensively examined in ALS. In our study, the activity of mitochondrial electron transport chain complex IV was examined in post‐mortem gray and white matter of the cervical and lumbar spinal cords from male and female sALS patients and controls. Mitochondrial distribution and density in spinal cord motor neurons, lateral funiculus, and capillaries in gray and white matter were analyzed by immunohistochemistry. Results showed that complex IV activity was significantly decreased only in gray matter in both cervical and lumbar spinal cords from ALS patients. In ALS cervical and lumbar spinal cords, significantly increased mitochondrial density and altered distribution were observed in motor neurons, lateral funiculus, and cervical white matter capillaries. Discrete decreased complex IV activity in addition to changes in mitochondria distribution and density determined in the spinal cord in sALS patients are novel findings. These explicit mitochondrial defects in the spinal cord may contribute to ALS pathogenesis and should be considered in development of therapeutic approaches for this disease.     

A role for the urokinase-type plasminogen activator system in amyotrophic lateral sclerosis

There is substantial evidence, implicating extracellular matrix (ECM) regulating enzymes in the pathogenesis of motor neuron degeneration in amyotrophic lateral sclerosis (ALS). The most important ECM-degrading proteases are serine proteases (plasminogen activators, PA) and matrix metalloproteinases (MMPs). Since the role of MMPs in ALS has been addressed recently, we investigated the expression of the serine protease urokinase-type plasminogen activator (uPA) and its receptor in ALS. Employing rtPCR, zymography and immunohistochemistry we analyzed the expression of uPA and its receptor uPAR in spinal cord tissue of ALS cases and in the G93A SOD1 transgenic mouse. In the ventral horn of the spinal cord of ALS cases we found increased uPAR staining of motor neurons. In G93A mice, the expression profile of uPA and uPAR mRNA was significantly increased starting at the age of 90 days as compared to non-transgenic littermates. The uPA-dependent plasminogen activation in G93A mice at endstage increased markedly compared with controls and immunostaining of the spinal cord from G93A mice revealed increased uPAR immunostaining in neurons. To determine the functional role of uPA, we investigated the effect of intraperitoneal (i.p.) administration of the uPA inhibitor WX-340 (10 mg/kg), starting at the age of 30 days (n=18). Treatment with WX-340 prolonged (p<0.05) survival of the animals (135+/-2 vs. 126+/-3) as well as improving rotarod performance. Our experiments demonstrate that uPA and its receptor are expressed in ALS patients and in an animal model of ALS. Early inhibition with a synthetic uPA inhibitor prolonged the life of the transgenic animals. These findings indicate that the urokinase-type plasminogen activator system may play a role in the complex pathogenesis of ALS.     

Motor neuron disease in mice expressing the wild type-like D90A mutant superoxide dismutase-1

Mutant human CuZn-superoxide dismutases (hSOD1s) cause amyotrophic lateral sclerosis (ALS). The most common mutation is the wild type-like D90A and to explore its properties, transgenic mice were generated and compared with mice expressing wild-type hSOD1. D90A hSOD1 was both in vivo in mice and in vitro under denaturing conditions nearly as stable as the wild-type human enzyme. It appeared less toxic than other tested mutants, but mice homozygous for the transgene insertion developed a fatal motor neuron disease. In these mice, the disease progression was slow and there were bladder disturbances similar to what is found in human ALS cases homozygous for the D90A mutation. The homozygous D90A mice accumulated detergent-resistant hSOD1 aggregates in spinal cords, and abundant hSOD1 inclusions and vacuoles were seen in the ventral horns. Mice expressing wild-type hSOD1 at a comparable rate showed similar pathologic changes but less and later. Hemizygous D90A mice showed even milder alterations. At 600 days, the wild-type hSOD1 transgenic mice had lost more ventral horn neurons than hemizygous D90A mice (38% vs 31% p < 0.01). Thus, wild-type hSOD1 shows a significant neurotoxicity in the spinal cord, that is less than equal but more than half as large as that of D90A mutant enzyme.     

Celastrol blocks neuronal cell death and extends life in transgenic mouse model of amyotrophic lateral sclerosis

There is substantial evidence that both inflammation and oxidative damage contribute to the pathogenesis of motor neuron degeneration in the G93A SOD1 transgenic mouse model of amyotrophic lateral sclerosis (ALS). Celastrol is a natural product from Southern China, which exerts potent anti-inflammatory and antioxidative effects. It also acts potently to increase expression of heat shock proteins including HSP70. We administered it in the diet to G93A SOD1 mice starting at 30 days of age. Celastrol treatment significantly improved weight loss, motor performance and delayed the onset of ALS. Survival of celastrol-treated G93A mice increased by 9.4% and 13% for 2 mg/kg/day and 8 mg/kg/day doses, respectively. Cell counts of lumbar spinal cord neurons confirmed a protective effect, i.e. 30% increase in neuronal number in the lumbar spinal cords of celastrol-treated animals. Celastrol treatment reduced TNF-alpha, iNOS, CD40, and GFAP immunoreactivity in the lumbar spinal cord sections of celastrol-treated G93A mice compared to untreated G93A mice. TNF-alpha immunoreactivity co-localized with SMI-32 (neuronal marker) and GFAP (astrocyte marker). HSP70 immunoreactivity was increased in lumbar spinal cord neurons of celastrol-treated G93A mice. Celastrol has been widely used in treating inflammatory diseases in man, and is well tolerated; therefore, it may be a promising therapeutic candidate for the treatment of human ALS.     

Stem cell factor‐activated bone marrow ameliorates amyotrophic lateral sclerosis by promoting protective microglial migration

Amyotrophic lateral sclerosis (ALS) is a progressive disease associated with motor neuron death. Several experimental treatments, including cell therapy using hematopoietic or neuronal stem cells, have been tested in ALS animal models, but therapeutic benefits have been modest. Here we used a new therapeutic strategy, bone marrow transplantation (BMT) with stem cell factor (SCF)‐ or FMS‐like tyrosine kinase 3 (flt3)‐activated bone marrow (BM) cells for the treatment of hSOD1(G93A) transgenic mice. Motor function and survival showed greater improvement in the SCF group than in the group receiving BM cells that had not been activated (BMT alone group), although no improvement was shown in the flt3 group. In addition, larger numbers of BM‐derived cells that expressed the microglia marker Iba1 migrated to the spinal cords of recipient mice compared with the BMT‐alone group. Moreover, after SCF activation, but not flt3 activation or no activation, the migrating microglia expressed glutamate transporter‐1 (GLT‐1). In spinal cords in the SCF group, inflammatory cytokines tumor necrosis factor‐α and interleukin‐1β were suppressed and the neuroprotective molecule insulin‐like growth factor‐1 increased relative to nontreatment hSOD1(G93A) transgenic mice. Therefore, SCF activation changed the character of the migrating donor BM cells, which resulted in neuroprotective effects. These studies have identified SCF‐activated BM cells as a potential new therapeutic agent for the treatment of ALS. © 2014 Wiley Periodicals, Inc.     

Therapeutic benefit of intrathecal injection of insulin-like growth factor-1 in a mouse model of Amyotrophic Lateral Sclerosis

Insulin-like growth factor (IGF)-1 has been shown to have a protective effect on motor neurons both in vitro and in vivo, but has limited efficacy in patients with amyotrophic lateral sclerosis (ALS) when given subcutaneously. To examine the possible effectiveness of IGF-1 in a mouse model of familial ALS, transgenic mice expressing human Cu/Zn superoxide dismutase (SOD1) with a G93A mutation were treated by continuous IGF-1 delivery into the intrathecal space of the lumbar spinal cord. We found that the intrathecal administration of IGF-1 improved motor performance, delayed the onset of clinical disease, and extended survival in the G93A transgenic mice. Furthermore, it increased the expression of phosphorylated Akt and ERK in spinal motor neurons, and partially prevented motor neuron loss in these mice. Taken together, the results suggest that direct administration of IGF-1 into the intrathecal space may have a therapeutic benefit for ALS.     

Amyotrophic lateral sclerosis: delayed disease progression in mice by treatment with a cannabinoid.

Effective treatment for amyotrophic lateral sclerosis (ALS) remains elusive. Two of the primary hypotheses underlying motor neuron vulnerability are susceptibility to excitotoxicity and oxidative damage. There is rapidly emerging evidence that the cannabinoid receptor system has the potential to reduce both excitotoxic and oxidative cell damage. Here we report that treatment with Delta(9)-tetrahydrocannabinol (Delta(9)-THC) was effective if administered either before or after onset of signs in the ALS mouse model (hSOD(G93A) transgenic mice). Administration at the onset of tremors delayed motor impairment and prolonged survival in Delta(9)-THC treated mice when compared to vehicle controls. In addition, we present an improved method for the analysis of disease progression in the ALS mouse model. This logistic model provides an estimate of the age at which muscle endurance has declined by 50% with much greater accuracy than could be attained for any other measure of decline. In vitro, Delta(9)-THC was extremely effective at reducing oxidative damage in spinal cord cultures. Additionally, Delta(9)-THC is anti-excitotoxic in vitro. These cellular mechanisms may underlie the presumed neuroprotective effect in ALS. As Delta(9)-THC is well tolerated, it and other cannabinoids may prove to be novel therapeutic targets for the treatment of ALS.