UMLS:C0002736 - FACTA Search

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Query: UMLS:C0002736 (amyotrophic lateral sclerosis)
19,048 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mutation in Cu/Zn-superoxide dismutase (SOD1) is a cause of familial amyotrophic lateral sclerosis (ALS). Mutant SOD1 protein (SOD1(mut)) induces motor neuron death, although the molecular mechanism of SOD1(mut)-induced cell death remains controversial. Here we show that SOD1(mut) specifically interacted with Derlin-1, a component of endoplasmic reticulum (ER)-associated degradation (ERAD) machinery and triggered ER stress through dysfunction of ERAD. SOD1(mut)-induced ER stress activated the apoptosis signal-regulating kinase 1 (ASK1)-dependent cell death pathway. Perturbation of binding between SOD1(mut) and Derlin-1 by Derlin-1-derived oligopeptide suppressed SOD1(mut)-induced ER stress, ASK1 activation, and motor neuron death. Moreover, deletion of ASK1 mitigated the motor neuron loss and extended the life span of SOD1(mut) transgenic mice. These findings demonstrate that ER stress-induced ASK1 activation, which is triggered by the specific interaction of Derlin-1 with SOD1(mut), is crucial for disease progression of familial ALS.
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PMID:ALS-linked mutant SOD1 induces ER stress- and ASK1-dependent motor neuron death by targeting Derlin-1. 1851 38

Unfolded protein responses, including induction of stress sensor kinases, chaperones, and apoptotic mediators, are involved in the familial amyotrophic lateral sclerosis (ALS) model related to mutant Cu/Zn superoxide dismutase (SOD1) and sporadic ALS. We hypothesized that the endoplasmic reticulum-resident factor Derlin-1 plays a pivotal role in the regulation of misfolded proteins evoked by mutant SOD1. We show that Derlin-1 overexpression reduced mutant SOD1-induced cell toxicity and increased cell viability by suppressing the activation of the ER stress pathway factors: immunoglobulin-binding protein, activating transcription factor 6 p50, and C/EBP homologous protein. Interestingly, exogenous Derlin-1 resulted in a decrease in the amount of mutant SOD1, and a lesser decrease in that of wild-type SOD1, in transfected cells. Reduced SOD1 protein expression was observed in the microsomal fraction of wild-type and mutant SOD1 cells. Our results indicate that Derlin-1 regulates the turn over of SOD1 by promoting the proteasomal and autophagosomal degradation of SOD1 protein, but not by decreasing mutant SOD1 mRNA levels. Insights into the effects of Derlin-1 on mutant SOD1 may facilitate advancements in the treatment of motor neuron degeneration associated with ALS.
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PMID:Derlin-1 overexpression ameliorates mutant SOD1-induced endoplasmic reticulum stress by reducing mutant SOD1 accumulation. 2118 45

Zinc is an essential trace element, and impaired zinc homeostasis is implicated in the pathogenesis of various human diseases. However, the mechanisms cells use to respond to zinc deficiency are poorly understood. We previously reported that amyotrophic lateral sclerosis (ALS)-linked pathogenic mutants of SOD1 cause chronic endoplasmic reticulum (ER) stress through specific interactions with Derlin-1, which is a component of the ER-associated degradation machinery. Moreover, we recently demonstrated that this interaction is common to ALS-linked SOD1 mutants, and wild-type SOD1 (SOD1(WT)) comprises a masked Derlin-1 binding region (DBR). Here, we found that, under zinc-deficient conditions, SOD1(WT) adopts a mutant-like conformation that exposes the DBR and induces the homeostatic ER stress response, including the inhibition of protein synthesis and induction of a zinc transporter. We conclude that SOD1 has a function as a molecular switch that activates the ER stress response, which plays an important role in cellular homeostasis under zinc-deficient conditions.
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PMID:SOD1 as a molecular switch for initiating the homeostatic ER stress response under zinc deficiency. 2407 20

Mutations in the Cu, Zn superoxide dismutase (SOD1) gene are one of the causative agents of amyotrophic lateral sclerosis (ALS). Although more than 100 different mutations in SOD1 have been identified, it is unclear whether all the mutations are pathogenic or just single nucleotide polymorphisms (SNPs) unrelated to the disease. Our previous systematic analysis found that all pathogenic SOD1 mutants (SOD1(mut)) have a common property, namely, an association with Derlin-1, a component of the endoplasmic reticulum-associated degradation machinery. For the proposed mechanism, we found that most pathogenic SOD1(mut) have a constitutively exposed Derlin-1-binding region (DBR), which is concealed in wild-type SOD1 (SOD1(WT)). Moreover, we generated MS785, a monoclonal antibody against DBR. MS785 distinguished most ALS-causative SOD1(mut) from both SOD1(WT) and non-toxic SOD1(mut). However, MS785 could not recognize SOD1(mut) that has mutations in the MS785 epitope region. Here, we developed a new diagnostic antibody, which could compensate for this shortcoming of MS785. We hypothesized that in ALS-causative SOD1(mut), the DBR-neighboring region [SOD1(30-40)] may also be exposed. We then generated MS27, a monoclonal antibody against SOD1(30-40). We found that MS27 could distinguish SOD1(WT) from the pathogenic SOD1(mut), which has mutations in the MS785 epitope region. Moreover, all pathogenic SOD1(mut), without exception, were immunoprecipitated with a combination of MS785 and MS27. The MS785-MS27 combination could be developed as a novel mechanism-based biomarker for the diagnosis of ALS.
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PMID:A systematic immunoprecipitation approach reinforces the concept of common conformational alterations in amyotrophic lateral sclerosis-linked SOD1 mutants. 2629 18

Mutations in Cu/Zn-superoxide dismutase (SOD1) cause familial amyotrophic lateral sclerosis (ALS). Previous papers showed that mutant SOD1 accumulates and undergoes misfolding in motor neurons and that the specific interaction of mutant SOD1 with derlin-1 leads to endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR). Because evidence shows that mutant SOD1 expression also damages sensory neurons, we hypothesized that, similarly to motor neurons, the sensory neurons of ALS mouse model SOD1(G93A) accumulate mutant/misfolded SOD1 and suffer from ER stress and UPR activation. Our results reveal that SOD1(G93A) sensory neurons accumulate mutant/misfolded SOD1 but, surprisingly, do not suffer from ER stress and UPR activation. Moreover, the sensory neurons do not express detectable levels of the SOD1 interactor derlin-1. These results suggest a potential molecular mechanism underlying the differential vulnerability of motor and sensory neurons to mutant SOD1 toxicity.
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PMID:Mutant SOD1 accumulation in sensory neurons does not associate with endoplasmic reticulum stress features: Implications for differential vulnerability of sensory and motor neurons to SOD1 toxicity. 2724 19

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder. Despite its severity, there are no effective treatments because of the complexity of its pathogenesis. As one of the underlying mechanisms of Cu, Zn superoxide dismutase (SOD1) gene mutation-induced ALS, SOD1 mutants (SOD1^mut) commonly interact with an endoplasmic reticulum-resident membrane protein Derlin-1, triggering motoneuron death. However, the importance of SOD1-Derlin-1 interaction in in vitro human model and in vivo mouse model remains to be elucidated. Here, we identify small-molecular-weight compounds that inhibit the SOD1-Derlin-1 interaction by screening approximately 160,000 compounds. The inhibitor prevents 122 types of SOD1^mut from interacting with Derlin-1, and significantly ameliorates the ALS pathology both in motoneurons derived from patient induced pluripotent stem cells and in model mice. Our data suggest that the SOD1-Derlin-1 interaction contributes to the pathogenesis of ALS and is a promising drug target for ALS treatment.
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PMID:A small-molecule inhibitor of SOD1-Derlin-1 interaction ameliorates pathology in an ALS mouse model. 2999 16

Cu, Zn superoxide dismutase (SOD1) is one of the genes implicated in the devastating neurodegenerative disorder amyotrophic lateral sclerosis (ALS). Although the precise mechanisms of SOD1 mutant (SOD1^mut)-induced motoneuron toxicity are still unclear, defects in SOD1 proteostasis are known to have a critical role in ALS pathogenesis. We previously reported that the SOD1^mut adopts a conformation that exposes a Derlin-1-binding region (DBR) and that DBR-exposed SOD1 interacts with Derlin-1, leading to motoneuron death. We also found that an environmental change, i.e. zinc depletion, induces a conformational change in WT SOD1 (SOD1^WT) to the DBR-exposed conformation, suggesting the presence of an equilibrium state between the DBR-masked and DBR-exposed states even with SOD1^WT Here, we conducted a high-throughput screening based on time-resolved FRET to further investigate the SOD1^WT conformational change, and we used a genome-wide siRNA screen to search for regulators of SOD1 proteostasis. This screen yielded 30 candidate genes that maintained an absence of the DBR-exposed SOD1^WT conformation. Among these genes was one encoding DDB1- and CUL4-associated factor 4 (DCAF4), a substrate receptor of the E3 ubiquitin-protein ligase complex. Of note, we found that DCAF4 mediates the ubiquitination of an ALS-associated protein and autophagy receptor, optineurin (OPTN), and facilitates autophagic degradation of DBR-exposed SOD1. In summary, our screen identifies DCAF4 as being required for proper proteostasis of DBR-exposed SOD1, which may have potential relevance for the development of therapies for managing ALS.
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PMID:Genome-wide siRNA screening reveals that DCAF4-mediated ubiquitination of optineurin stimulates autophagic degradation of Cu,Zn-superoxide dismutase. 3201 91