Superoxide Dismutase 1 G93A Mice Research Articles

Activating mitofusins interrupts mitochondrial degeneration and delays disease progression in SOD1 mutant amyotrophic lateral sclerosis.

Mitochondrial involvement in neurodegenerative diseases is widespread and multifactorial. Targeting mitochondrial pathology is therefore of interest. The recent development of bioactive molecules that modulate mitochondrial dynamics (fusion, fission and motility) offers a new therapeutic approach for neurodegenerative diseases with either indirect or direct mitochondrial involvement. Here, we asked: (1) Can enhanced mitochondrial fusion and motility improve secondary mitochondrial pathology in superoxide dismutase1 (SOD1) mutant amyotrophic lateral sclerosis (ALS)? And: (2) What is the impact of enhancing mitochondria fitness on in vivo manifestations of SOD1 mutant ALS? We observed that small molecule mitofusin activators corrected mitochondrial fragmentation, depolarization and dysmotility in genetically diverse ALS patient reprogrammed motor neurons and fibroblasts, and in motor neurons, sensory neurons and fibroblasts from SOD1 G93A mice. Continuous, but not intermittent, pharmacologic mitofusin activation delayed phenotype progression and lethality in SOD1 G93A mice, reducing neuron loss and improving neuromuscular connectivity. Mechanistically, mitofusin activation increased mitochondrial motility, fitness and residency within neuromuscular synapses; reduced mitochondrial reactive oxygen species production; and diminished apoptosis in SOD1 mutant neurons. These benefits were accompanied by improved mitochondrial respiratory coupling, despite characteristic SOD1 mutant ALS-associated downregulation of mitochondrial respiratory complexes. Targeting mitochondrial dysdynamism is a promising approach to alleviate pathology caused by secondary mitochondrial dysfunction in some neurodegenerative diseases.

α-Amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptor and RNA processing gene dysregulation are early determinants of selective motor neuron vulnerability in a mouse model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a late-onset adult neurodegenerative disease, although there is mounting electrophysiological and pathological evidence from patients and animal models for a protracted preclinical period of motor neuron susceptibility and dysfunction, long before clinical diagnosis. The key molecular mechanisms linked to motor neuron vulnerability in amyotrophic lateral sclerosis have been extensively studied using transcriptional profiling in motor neurons isolated from adult mutant superoxide dismutase 1 mice. However, neonatal and embryonic motor neurons from mutant superoxide dismutase 1 mice show abnormal morphology and hyperexcitability, suggesting preceding transcriptional dysregulation. Here, we used RNA sequencing on motor neurons isolated from embryonic superoxide dismutase 1G93A mice to determine the earliest molecular mechanisms conferring neuronal susceptibility and dysfunction known in a mouse model of amyotrophic lateral sclerosis. Transgenic superoxide dismutase 1G93A mice expressing the spinal motor neuron homeobox HB9:green fluorescent protein reporter allowed unambiguous identification and isolation of motor neurons using fluorescence-activated cell sorting. Gene expression profiling of isolated motor neurons revealed transcriptional dysregulation in superoxide dismutase 1G93A mice as early as embryonic Day 12.5 with the majority of differentially expressed genes involved in RNA processing and α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate-mediated glutamate receptor signalling. We confirmed dysregulation of the α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptor Subunit 2, at transcript and protein levels, in embryonic superoxide dismutase 1G93A mouse motor neurons and human motor neurons derived from amyotrophic lateral sclerosis patient induced pluripotent stem cells harbouring pathogenic superoxide dismutase 1 mutations. Mutant superoxide dismutase 1 induced pluripotent stem cell-derived motor neurons showed greater vulnerability to α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate-mediated excitotoxicity, consistent with α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptor Subunit 2 downregulation. Thus, α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptor Subunit 2 deficiency leading to enhanced α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptor signalling, calcium influx, hyperexcitability, and chronic excitotoxicity is a very early and intrinsic property of spinal motor neurons that may trigger amyotrophic lateral sclerosis pathogenesis later in life. This study reinforces the concept of therapeutic targeting of hyperexcitability and excitotoxicity as potential disease-modifying approaches for amyotrophic lateral sclerosis.

Chlorovirus ATCV-1 Accelerates Motor Deterioration in SOD1-G93A Transgenic Mice and Its SOD1 Augments Induction of Inflammatory Factors From Murine Macrophages.

BackgroundGenetically polymorphic Superoxide Dismutase 1 G93A (SOD1-G93A) underlies one form of familial Amyotrophic Lateral Sclerosis (ALS). Exposures from viruses may also contribute to ALS, possibly by stimulating immune factors, such as IL-6, Interferon Stimulated Genes, and Nitric Oxide. Recently, chlorovirus ATCV-1, which encodes a SOD1, was shown to replicate in macrophages and induce inflammatory factors.ObjectiveThis study aimed to determine if ATCV-1 influences development of motor degeneration in an ALS mouse model and to assess whether SOD1 of ATCV-1 influences production of inflammatory factors from macrophages.MethodsSera from sporadic ALS patients were screened for antibody to ATCV-1. Active or inactivated ATCV-1, saline, or a viral mimetic, polyinosinic:polycytidylic acid (poly I:C) were injected intracranially into transgenic mice expressing human SOD1-G93A- or C57Bl/6 mice. RAW264.7 mouse macrophage cells were transfected with a plasmid vector expressing ATCV-1 SOD1 or an empty vector prior to stimulation with poly I:C with or without Interferon-gamma (IFN-γ).ResultsSerum from sporadic ALS patients had significantly more IgG1 antibody directed against ATCV-1 than healthy controls. Infection of SOD1-G93A mice with active ATCV-1 significantly accelerated onset of motor loss, as measured by tail paralysis, hind limb tucking, righting reflex, and latency to fall in a hanging cage-lid test, but did not significantly affect mortality when compared to saline-treated transgenics. By contrast, poly I:C treatment significantly lengthened survival time but only minimally slowed onset of motor loss, while heat-inactivated ATCV-1 did not affect motor loss or survival. ATCV-1 SOD1 significantly increased expression of IL-6, IL-10, ISG promoter activity, and production of Nitric Oxide from RAW264.7 cells.ConclusionATCV-1 chlorovirus encoding an endogenous SOD1 accelerates pathogenesis but not mortality, while poly I:C that stimulates antiviral immune responses delays mortality in an ALS mouse model. ATCV-1 SOD1 enhances induction of inflammatory factors from macrophages.

A Novel HGF/SF Receptor (MET) Agonist Transiently Delays the Disease Progression in an Amyotrophic Lateral Sclerosis Mouse Model by Promoting Neuronal Survival and Dampening the Immune Dysregulation.

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease with no effective treatment. The Hepatocyte Growth Factor/Scatter Factor (HGF/SF), through its receptor MET, is one of the most potent survival-promoting factors for motor neurons (MN) and is known as a modulator of immune cell function. We recently developed a novel recombinant MET agonist optimized for therapy, designated K1K1. K1K1 was ten times more potent than HGF/SF in preventing MN loss in an in vitro model of ALS. Treatments with K1K1 delayed the onset of muscular impairment and reduced MN loss and skeletal muscle denervation of superoxide dismutase 1 G93A (SOD1G93A) mice. This effect was associated with increased levels of phospho-extracellular signal-related kinase (pERK) in the spinal cord and sciatic nerves and the activation of non-myelinating Schwann cells. Moreover, reduced activated microglia and astroglia, lower T cells infiltration and increased interleukin 4 (IL4) levels were found in the lumbar spinal cord of K1K1 treated mice. K1K1 treatment also prevented the infiltration of T cells in skeletal muscle of SOD1G93A mice. All these protective effects were lost on long-term treatment suggesting a mechanism of drug tolerance. These data provide a rational justification for further exploring the long-term loss of K1K1 efficacy in the perspective of providing a potential treatment for ALS.

Wild-type p53-induced phosphatase 1 down-regulation promotes apoptosis by activating the DNA damage-response pathway in amyotrophic lateral sclerosis

Accumulation of DNA damage has been detected in the spinal cord of patients as well as in the G93A mouse model of amyotrophic lateral sclerosis (ALS). Wild-type p53-induced phosphatase 1 (Wip1) is a p53-inducible serine/threonine phosphatase that terminates DNA-damage responses via dephosphorylation of DNA-damage response proteins, namely ataxia-telangiectasia mutated (ATM) kinase, checkpoint kinase 2, and p53, thus enhancing cell proliferation. However, the role of Wip1, DNA-damage responses, and their interaction in ALS development remains to be elucidated. Here, we showed that Wip1 expression levels were substantially decreased in ALS motor neurons compared with wild-type controls both in vivo and in vitro. The DNA-damage response was activated in superoxide dismutase 1 (SOD1) G93A-transfected cells. However, increased expression of Wip1 improved cell viability and inhibited the DNA-damage response in mutated SOD1G93A cells. Further studies demonstrated that decreased Wip1 expression reduced cell viability and further activated the DNA-damage response in chronic H2O2-treated NSC34 cells. In contrast, Wip1 promoted cell survival and suppressed DNA damage-induced apoptosis during persistent DNA damage conditions. Over-expression of Wip1 in the central nervous system (CNS) can delay the onset of disease symptoms, extended the survival, decreased MN loss improved motor function and inhibit the DNA-damage response in SOD1 G93A mice. Furthermore, homeodomain-interacting protein kinase 2 (HIPK2) promoted the degradation of Wip1 via the ubiquitin-proteasome system during chronic stress. These findings indicate that persistent accumulation of DNA damage and subsequent chronic activation of the downstream DNA damage-response ATM and p53 pro-apoptotic signaling pathways may trigger neuronal dysfunction and neuronal death in ALS. Wip1 may play a protective role by targeting the DNA-damage response in ALS motor neurons. Importantly, these findings provide a novel direction for therapeutic options for patients with ALS.

Novel behavioural characteristics of the superoxide dismutase 1 G93A (SOD1G93A ) mouse model of amyotrophic lateral sclerosis include sex-dependent phenotypes.

Amyotrophic lateral sclerosis (ALS) involves the rapid degeneration of upper and lower motor neurons leading to weakening and paralysis of voluntary movements. Mutations in copper-zinc superoxide dismutase 1 (SOD1) are a known genetic cause of ALS, and the SOD1 G93A mouse has been used extensively to investigate molecular mechanisms in ALS. In recent years, evidence suggests that ALS and frontotemporal dementia form a spectrum disorder ranging from motor to cognitive dysfunctions. Thus, we tested male and female SOD1 G93A mice for the first time before the onset of debilitating motor impairments in behavioural domains relevant to both ALS and frontotemporal dementia. SOD1 G93A males displayed reduced locomotion, exploration and increased anxiety-like behaviours compared with control males. Intermediate-term spatial memory was impaired in SOD1 G93A females, whereas long-term spatial memory deficits as well as lower acoustic startle response, and prepulse inhibition were identified in SOD1 G93A mice of both sexes compared with respective controls. Interestingly, SOD1 G93A males exhibited an increased conditioned cue freezing response. Nosing behaviours were also elevated in both male and female SOD1 G93A when assessed in social paradigms. In conclusion, SOD1 G93A mice exhibit a variety of sex-specific behavioural deficits beyond motor impairments supporting the notion of an ALS-frontotemporal spectrum disorder. Thus, SOD1 G93A mice may represent a useful model to test the efficacy of therapeutic interventions on clinical symptoms in addition to declining motor abilities.

FGF9 modulates Schwann cell myelination in developing nerves and induces a pro‐inflammatory environment during injury

Myelin sheath is critical for the proper functioning of the peripheral nervous system (PNS), which allows the effective conduction of nerve impulses. Fibroblast growth factor 9 (FGF9) is an autocrine and paracrine protein in the fibroblast growth factor family that regulates cell differentiation and proliferation. Fgf9 Schwann cell (SC) conditional knockout mice were developed to detect the role of FGF9 in the PNS. In our study, the absence of Fgf9 led to delayed myelination in early development. The expression of mature SC-related genes decreased, and the expression of genes associated with immature SCs increased in the Fgf9 knockout mice. These data were consistent with the morphology and praxeology we observed during the development of the peripheral nerves. Extracellular-regulated kinases 1/2 (ERK1/2) are key signals for myelination, and our results showed that Fgf9 ablation led to the inactivation of ERK1/2. Further research was performed to detect the role of FGF9 in peripheral nerve injury. In superoxide dismutase 1-G93A mice with Fgf9 SC knockout, we found that Fgf9 ablation inhibited the expressions of Cd68, Il-1β, and Cd86, which contributed to the degeneration of the axon and myelin sheath.

Expression and Distribution of Arylsulfatase B are Closely Associated with Neuron Death in SOD1 G93A Transgenic Mice.

The known proteins only explained the partial pathogenesis of amyotrophic lateral sclerosis (ALS). Therefore, this study aimed to search the novel proteins possibly involved in ALS. In this study, we analyzed the expression and distribution of the candidate protein arylsulfatase B (ARSB) in the different segments, anatomic regions, and neural cells of spinal cord at the different stages of the wild-type and [Cu/Zn] superoxide dismutase 1 (SOD1) G93A transgenic mice using the fluorescent immunohistochemistry and the western blot. The results revealed that the ARSB was extensively expressed and distributed in the entire spinal cord; the expression and distribution of ARSB was significantly different in the different regions of spinal cord, the anterior horn of gray matter (AHGM) was significantly more than that in the posterior horn of gray matter (PHGM) and significantly more than that in the central canal, and ARSB was mainly distributed in the microglia and neuron cells in the wild-type mice. The expression of ARSB significantly increased in other anatomic regions besides the thoracic PHGM, significantly decreased at the progression stage, occurred in the redistribution from the AHGM and the PHGM to the central canal at the onset and progression stages, and no any alteration of ARSB expression and distribution occurred between the different neural cells in the SOD1 G93A mice compared with the wild-type mice. The increase of ARSB expression and distribution followed with the increased of neuron death. Our data suggested that the abnormal expression and distribution of ARSB were closely associated with the neuron death in the SOD1 G93A transgenic mice.

Emerging roles for neuropeptides in neuro-immune regulation in amyotrophic lateral sclerosis: Lessons from the superoxide dismutase 1-G93A mouse model

Emerging roles for neuropeptides in neuro-immune regulation in amyotrophic lateral sclerosis: Lessons from the superoxide dismutase 1-G93A mouse model

Human mesenchymal stromal cell transplantation modulates neuroinflammatory milieu in a mouse model of amyotrophic lateral sclerosis

Background aimsMesenchymal stromal cells (MSCs), after intraparenchymal, intrathecal and endovenous administration, have been previously tested for cell therapy in amyotrophic lateral sclerosis in the SOD1 (superoxide dismutase 1) mouse. However, every administration route has specific pros and cons. MethodsWe administrated human MSCs (hMSCs) in the cisterna lumbaris, which is easily accessible and could be used in outpatient surgery, in the SOD1 G93A mouse, at the earliest onset of symptoms. Control animals received saline injections. Motor behavior was checked starting from 2 months of age until the mice were killed. Animals were killed 2 weeks after transplantation; lumbar motoneurons were stereologically counted, astrocytes and microglia were analyzed and quantified after immunohistochemistry and cytokine expression was assayed by means of real-time polymerase chain reaction. ResultsWe provide evidence that this route of administration can exert strongly positive effects. Motoneuron death and motor decay were delayed, astrogliosis was reduced and microglial activation was modulated. In addition, hMSC transplantation prevented the downregulation of the anti-inflammatory interleukin-10, as well as that of vascular endothelial growth factor observed in saline-treated transgenic mice compared with wild type, and resulted in a dramatic increase in the expression of the anti-inflammatory interleukin-13. ConclusionsOur results suggest that hMSCs, when intracisternally administered, can exert their paracrine potential, influencing the inflammatory response of the host.

Blood Volatile Organic Compounds as Potential Biomarkers for Amyotrophic Lateral Sclerosis: an Animal Study in the SOD1 G93A Mouse

Amyotrophic lateral sclerosis (ALS) is a rapid progressive motor neuron disease. Currently, there are no specific or reliable biomarkers for the diagnosis of this disease, and there are no effective medical treatments. The early diagnosis and treatment of this disease has the potential to prolong the survival of ALS patients, but typically, approximately 1 year passes between the onset of symptoms and the diagnosis of this disease. Therefore, there is an urgent need to find specific biomarkers to enable early diagnosis and therapeutic intervention in this disease. Analyzing the volatile organic compounds (VOCs) present in the blood and exhaled breath is a useful and convenient approach for investigating potential biomarkers. In this study, we examined the VOCs present in blood samples from copper zinc superoxide dismutase 1 (SOD1) glycine to alanine mutation at position 93 (G93A) mice to determine whether a specific biomarker pattern exists in these transgenic mice. Blood samples from ALS mice and their age-matched littermates were analyzed using gas chromatography-mass spectrometry. A total of 12 independent compounds associated with oxidative stress were identified at the early stage of disease. The data show that there is a specific pattern of blood VOCs in ALS mice that could potentially be used as biomarkers that could improve the diagnosis of this disease. Furthermore, these compounds could also potentially be used to monitor the response to neuroprotective agents and to help us better understand the underlying mechanisms of ALS.

Guanabenz delays the onset of disease symptoms, extends lifespan, improves motor performance and attenuates motor neuron loss in the SOD1 G93A mouse model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive neurodegenerative disease characterized by the loss of motor neurons in the motor cortex, brain stem and spinal cord. Currently, there is no cure for this lethal disease. Although the mechanism underlying neuronal cell death in ALS remains elusive, growing evidence supports a crucial role of endoplasmic reticulum (ER) stress in the pathogenesis of ALS. Recent reports show that guanabenz, a novel inhibitor of eukaryotic initiation factor 2α (eIF2α) dephosphorylation, possesses anti-prion properties, attenuates ER stress and reduces paralysis and neurodegeneration in mTDP-43 Caenorhabditis elegans and Danio rerio models of ALS. However, the therapeutic potential of guanabenz for the treatment of ALS has not yet been assessed in a mouse model of ALS. In the present study, guanabenz was administered to a widely used mouse model of ALS expressing copper zinc superoxide dismutase-1 (SOD1) with a glycine to alanine mutation at position 93 (G93A). The results showed that the administration of guanabenz significantly extended the lifespan, delayed the onset of disease symptoms, improved motor performance and attenuated motor neuron loss in female SOD1 G93A mice. Moreover, western blotting results revealed that guanabenz dramatically increased the levels of phosphorylated-eIF2α (P-eIF2α) protein, without affecting total eIF2α protein levels. The results also revealed a significant decrease in the levels of the ER chaperone glucose-regulated protein 78 (BiP/Grp78) and markers of another two ER stress pathways, activating transcription factor 6α (ATF6α) and inositol-requiring enzyme 1 (IRE1). In addition, guanabenz increased the protein levels of anti-apoptotic B cell lymphoma/lewkmia-2 (Bcl-2), and down-regulated the pro-apoptotic protein levels of C/EBP homologous protein (CHOP), Bcl-2-associated X protein (BAX) and cytochrome C in SOD1 G93A mice. Our findings indicate that guanabenz may represent a novel therapeutic candidate for the treatment of ALS, a lethal human disease with an underlying mechanism involving the attenuation of ER stress and mitochondrial stress via prolonging eIF2α phosphorylation.

Survival motor neuron deficiency enhances progression in an amyotrophic lateral sclerosis mouse model

Mutations in the ubiquitously expressed survival motor neuron 1 ( SMN1) and superoxide dismutase 1 ( SOD1) genes are selectively lethal to motor neurons in spinal muscular atrophy (SMA) and familial amyotrophic lateral sclerosis (ALS), respectively. Genetic association studies provide compelling evidence that SMN1 and SMN2 genotypes encoding lower SMN protein levels are implicated in sporadic ALS, suggesting that SMN expression is a potential determinant of ALS severity. We therefore sought genetic evidence of SMN involvement in ALS by generating transgenic mutant SOD1 mice on an Smn deficient background. Partial genetic disruption of Smn significantly worsened motor performance and survival in transgenic SOD1 G93A mice. Furthermore, ALS-linked mutant SOD1 expression severely reduced SMN protein levels, but not transcript, in neuronal culture and mouse models from early presymptomatic disease. SMN protein depletion was linked to the nuclear compartment and a physical interaction between SMN and mutant SOD1 was confirmed in mouse spinal cord. Treatment with the environmental toxin paraquat also depleted SMN protein, implicating oxidative stress in the mechanism underlying SMN deficiency in familial ALS and potentially sporadic disease. In contrast, transgenic SOD1 WT overexpression in SMA type I mice was incapable of modulating SMN protein levels or disease progression. These data establish that SMN deficiency accelerates phenotypic severity in transgenic familial ALS mice, consistent with an enhancing genetic modifier role. We therefore propose that SMN replacement and upregulation strategies considered for SMA therapy may have protective potential for ALS.

Targeted Antioxidative and Neuroprotective Properties of the Dopamine Agonist Pramipexole and Its Nondopaminergic Enantiomer SND919CL2x [(+)2-Amino-4,5,6,7-tetrahydro-6-lpropylamino-benzathiazole Dihydrochloride

Pramipexole has been shown to possess neuroprotective properties in vitro that are partly independent of its dopaminergic agonism. The site of neuroprotective action is still unknown. Using [(3)H]pramipexole, we show that the drug enters and accumulates in cells and mitochondria. Detoxification of reactive oxygen species (ROS) by pramipexole is shown in vitro and in vivo by evaluating mitochondrial ROS release and aconitase-2 activity, respectively. Pramipexole and its (+)-enantiomer SND919CL2X [low-affinity dopamine agonist; (+)2-amino-4,5,6,7-tetrahydro-6-l-propylamino-benzathiazole dihydrochloride] possess equipotent efficacy toward hydrogen peroxide and nitric oxide generated in vitro and inhibit cell death in glutathione-depleted neuroblastoma cells. IC(50) values ranged from 15 to 1000 microM, consistent with the reactivity of the respective radical and the compartmentalization of ROS generation and ROS detoxification. Finally, both compounds were tested in superoxide dismutase 1-G93A mice, a model of familial amyotrophic lateral sclerosis. SND919CL2X (100 mg/kg) prolongs survival time and preserves motor function in contrast to pramipexole (3 mg/kg), which shows an increase in running wheel activity before disease onset, presumably caused by the dopaminergic agonism. We conclude that both enantiomers, in addition to their dopaminergic activity, are able to confer neuroprotective effects by their ability to accumulate in brain, cells, and mitochondria where they detoxify ROS. However, a clinical use of pramipexole as a mitochondria-targeted antioxidant is unlikely, because the high doses needed for antioxidative action in vitro are not accessible in vivo due to dopaminergic side effects. In contrast, SND919CL2X may represent the prototype of a mitochondria-targeted neuroprotectant because it has the same antioxidative properties without causing adverse effects.

Neuromuscular accumulation of mutant superoxide dismutase 1 aggregates in a transgenic mouse model of familial amyotrophic lateral sclerosis

Superoxide dismutase 1 (SOD1) aggregates are a histological and biochemical correlate of disease progression in neural tissues from mutant SOD1-linked forms of familial amyotrophic lateral sclerosis (FALS). In the present study, we assayed the monomeric and high molecular weight mutant SOD1 content of nervous, muscle and visceral tissues from transgenic SOD1 G93A mice using immunoblotting and zymograms. A progressive age-dependent increase in mutant SOD1 level, aggregation and stabilisation by cross-species heterodimers was determined in lumbar spinal cord, sciatic nerve and gastrocnemius muscle. Such biochemical abnormalities were not present in cervical spinal cord, brainstem and diaphragm muscle, nor common to endogenous mouse SOD1. Mutant dismutase activity in general did not increase correspondingly with accumulating protein at later ages. These results suggest that peripheral targets such as hindlimb skeletal muscle and nerve accumulate mutant SOD1 aggregates and may therefore be susceptible to mutant SOD1-mediated toxicity, in addition to lower and upper motor neurons of the central nervous system in transgenic FALS mice.

Dissociation between Neurodegeneration and Caspase-11-Mediated Activation of Caspase-1 and Caspase-3 in a Mouse Model of Amyotrophic Lateral Sclerosis

Caspase-11 is a key regulator of caspase-1 and caspase-3 activation under pathological conditions. We show here that the expression of caspase-11 is upregulated in the spinal cord of superoxide dismutase 1 (SOD1) G93A transgenic mice, a mouse model of amyotrophic lateral sclerosis (ALS), before the onset of motor dysfunction and remains at the high levels throughout the course of disease. The caspase-1- and caspase-3-like activities, as well as the level of interleukin-1beta, were significantly reduced in the spinal cord of symptomatic caspase-11-/-;SOD1 G93A mice compared with that of caspase-11+/-; SOD1 G93A mice. However, neurodegeneration, inflammatory responses, and the disease onset and progression in SOD1 G93A transgenic mice were not altered by the ablation of caspase-11 gene. Thus, although caspases may contribute to certain aspects of pathology in this mouse model of ALS, their inhibition is not sufficient to prevent neurodegeneration. Our study urges caution when considering the inhibition of caspases as a direct therapeutic method for the treatment of chronic neurodegenerative diseases.