scholarly journals A yeast model of the ALS protein Matrin3 uncovers Hsp90 and its co-chaperone Sti1 as modifiers of misfolding and toxicity

2021 ◽  
Author(s):  
Sonja E. Di Gregorio ◽  
Mohammad Esmaeili ◽  
Ahmed Salem ◽  
Martin L. Duennwald

AbstractThe MATR3 gene encoding the protein Matrin3 is implicated in the pathogenesis of the neurodegenerative disease amyotrophic lateral sclerosis (ALS). Matrin3 forms neuronal cytoplasmic and nuclear inclusions in ALS-affected neurons. Additionally, 13 heterozygous missense mutations in MATR3 are identified in ALS patients. To further explore Matrin3 misfolding and toxicity, we established and characterized a yeast model. We demonstrate that wild type Matrin3 and the ALS-associated variant F115C are toxic and form inclusions in yeast. Our further characterization uncovers substantial modification of Matrin3 toxicity and inclusion formation by Hsp90 and its co-chaperones, specifically Sti1. Thus, our study demonstrates how specific branches of cellular protein quality control regulate the misfolding and toxicity of Matrin3.Summary StatementWe established and characterized a yeast model expressing human Matrin3, a protein implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). Using this yeast model and mammalian neuronal cells, we showed that Matrin3 mislocalizes and forms inclusions, is cytotoxic, and increases sensitivity to cellular stress. We also uncovered that Hsp90 and particularly its co-chaperone Sti1 alter Matrin3 toxicity.

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Claire Guissart ◽  
Kevin Mouzat ◽  
Jovana Kantar ◽  
Baptiste Louveau ◽  
Paul Vilquin ◽  
...  

AbstractAmyotrophic lateral sclerosis (ALS) is the most common and severe adult-onset motoneuron disease and has currently no effective therapy. Approximately 20% of familial ALS cases are caused by dominantly-inherited mutations in the gene encoding Cu/Zn superoxide dismutase (SOD1), which represents one of the most frequent genetic cause of ALS. Despite the overwhelming majority of ALS-causing missense mutations in SOD1, a minority of premature termination codons (PTCs) have been identified. mRNA harboring PTCs are known to be rapidly degraded by nonsense-mediated mRNA decay (NMD), which limits the production of truncated proteins. The rules of NMD surveillance varying with PTC location in mRNA, we analyzed the localization of PTCs in SOD1 mRNA to evaluate whether or not those PTCs can be triggered to degradation by the NMD pathway. Our study shows that all pathogenic PTCs described in SOD1 so far can theoretically escape the NMD, resulting in the production of truncated protein. This finding supports the hypothesis that haploinsufficiency is not an underlying mechanism of SOD1 mutant-associated ALS and suggests that PTCs found in the regions that trigger NMD are not pathogenic. Such a consideration is particularly important since the availability of SOD1 antisense strategies, in view of variant treatment assignment.


Author(s):  
Soojie Hong

Dr. Martin L. Duennwald is a researcher and assistant professor at Western University. After conducting independent research at the Boston Biomedical Research Institute, he came to Western University in 2012 where he started the Duennwald Lab. His lab focuses on cellular protein quality control, protein misfolding and their pathological consequences in neurodegenerative diseases such as Huntington’s disease, Parkinson’s disease, and Amyotrophic Lateral Sclerosis (ALS).


US Neurology ◽  
2010 ◽  
Vol 05 (02) ◽  
pp. 35 ◽  
Author(s):  
Edor Kabashi ◽  
Paul N Valdmanis ◽  
Hussein Daoud ◽  
Véronique V Belzil ◽  
Patrick A Dion ◽  
...  

Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disorder and the third most common neurodegenerative cause of adult death after Alzheimer’s and Parkinson’s diseases. TAR DNA binding protein (TDP-43) has been found to be a major component of inclusion bodies in motor neurons of ALS patients. Inclusion bodies are protein aggregates considered a pathological hallmark of neurodegeneration. Our group and eight independent research groups screened TDP-43 for mutations. Overall, 19 missense mutations and one truncating mutation were identified only in ALS patients. These mutations were not found in a considerable number of controls sequenced in several independent studies. Ten of these mutations were found in patients with a family history of ALS. To further support a pathogenic role, the mutations segregated with the disease in three families, including one family with a significant logarithm of odds (LOD) score. Nineteen of these 20 mutations are located in the C-terminus of the TDP-43 protein. These mutations could disrupt several of the already known functions of TDP-43, including nuclear localization, exon splicing, and RNA and heterogenous ribonucleoprotein particle (hnRNP) binding, or could introduce a novel gain of function that is toxic to motor neurons. In the future, animal and cellular models using these mutations should elucidate the role of TDP-43 mutations in ALS pathogenesis and could provide new means to test pharmaceutical compounds for this neurological disease.


Genes ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 84
Author(s):  
Alma Osmanovic ◽  
Isabel Gogol ◽  
Helge Martens ◽  
Maylin Widjaja ◽  
Kathrin Müller ◽  
...  

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive upper and lower motor neuron (LMN) loss. As ALS and other neurodegenerative diseases share genetic risk factors, we performed whole-exome sequencing in ALS patients focusing our analysis on genes implicated in neurodegeneration. Thus, variants in the DHTKD1 gene encoding dehydrogenase E1 and transketolase domain containing 1 previously linked to 2-aminoadipic and 2-oxoadipic aciduria, Charcot-Marie-Tooth (CMT) disease type 2, and spinal muscular atrophy (SMA) were identified. In two independent European ALS cohorts (n = 643 cases), 10 sporadic cases of 225 (4.4%) predominantly sporadic patients of cohort 1, and 12 familial ALS patients of 418 (2.9%) ALS families of cohort 2 harbored 14 different rare heterozygous DHTKD1 variants predicted to be deleterious. Four DHTKD1 variants were previously described pathogenic variants, seven were recurrent, and eight were located in the E1_dh dehydrogenase domain. Nonsense variants located in the E1_dh domain were significantly more prevalent in ALS patients versus controls. The phenotype of ALS patients carrying DHTKD1 variants partially overlapped with CMT and SMA by presence of sensory impairment and a higher frequency of LMN-predominant cases. Our results argue towards rare heterozygous DHTKD1 variants as potential contributors to ALS phenotype and, possibly, pathogenesis.


2020 ◽  
Vol 17 (3) ◽  
pp. 275-285 ◽  
Author(s):  
Si Chen ◽  
Qiao Liao ◽  
Ke Lu ◽  
Jinxia Zhou ◽  
Cao Huang ◽  
...  

Background: Amyotrophic lateral sclerosis (ALS) is a neurological disorder clinically characterized by motor system dysfunction, with intraneuronal accumulation of the TAR DNAbinding protein 43 (TDP-43) being a pathological hallmark. Riluzole is a primarily prescribed medicine for ALS patients, while its therapeutical efficacy appears limited. TDP-43 transgenic mice are existing animal models for mechanistic/translational research into ALS. Methods: We developed a transgenic rat model of ALS expressing a mutant human TDP-43 transgene (TDP-43M337V) and evaluated the therapeutic effect of Riluzole on this model. Relative to control, rats with TDP-43M337V expression promoted by the neurofilament heavy subunit (NEF) gene or specifically in motor neurons promoted by the choline acetyltransferase (ChAT) gene showed progressive worsening of mobility and grip strength, along with loss of motor neurons, microglial activation, and intraneuronal accumulation of TDP-43 and ubiquitin aggregations in the spinal cord. Results: Compared to vehicle control, intragastric administration of Riluzole (30 mg/kg/d) did not mitigate the behavioral deficits nor alter the neuropathologies in the transgenics. Conclusion: These findings indicate that transgenic rats recapitulate the basic neurological and neuropathological characteristics of human ALS, while Riluzole treatment can not halt the development of the behavioral and histopathological phenotypes in this new transgenic rodent model of ALS.


2021 ◽  
pp. 1-5
Author(s):  
João Morgadinho ◽  
Ana Catarina Pronto-Laborinho ◽  
Vasco A. Conceição ◽  
Marta Gromicho ◽  
Susana Pinto ◽  
...  

In amyotrophic lateral sclerosis (ALS) lower plasma creatinine level has been associated with shorter survival and faster functional decline. It has not been clear if creatinine is associated with respiratory outcome. We analyzed retrospectively a population of unselected ALS patients. Multiple-regression and Cox-regression analyses were performed. We included 233 patients, mean age 62.8, mean disease duration of 18.6 months. At baseline, creatinine was significantly associated with ALSFRS-R, but not with its decline rate. No predictive value was disclosed for FVC, or their decline rate, or with survival. We did not confirm that creatinine is a marker of respiratory outcome.


Author(s):  
Georgiana Soares Leandro ◽  
Mário Emílio Teixeira Dourado Júnior ◽  
Glauciane Costa Santana ◽  
Luan Samy Xavier Dantas

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
James C. Dodge ◽  
Jinlong Yu ◽  
S. Pablo Sardi ◽  
Lamya S. Shihabuddin

AbstractAberrant cholesterol homeostasis is implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS), a fatal neuromuscular disease that is due to motor neuron (MN) death. Cellular toxicity from excess cholesterol is averted when it is enzymatically oxidized to oxysterols and bile acids (BAs) to promote its removal. In contrast, the auto oxidation of excess cholesterol is often detrimental to cellular survival. Although oxidized metabolites of cholesterol are altered in the blood and CSF of ALS patients, it is unknown if increased cholesterol oxidation occurs in the SC during ALS, and if exposure to oxidized cholesterol metabolites affects human MN viability. Here, we show that in the SOD1G93A mouse model of ALS that several oxysterols, BAs and auto oxidized sterols are increased in the lumbar SC, plasma, and feces during disease. Similar changes in cholesterol oxidation were found in the cervical SC of sporadic ALS patients. Notably, auto-oxidized sterols, but not oxysterols and BAs, were toxic to iPSC derived human MNs. Thus, increased cholesterol oxidation is a manifestation of ALS and non-regulated sterol oxidation likely contributes to MN death. Developing therapeutic approaches to restore cholesterol homeostasis in the SC may lead to a treatment for ALS.


2021 ◽  
Vol 11 (7) ◽  
pp. 906
Author(s):  
Nimeshan Geevasinga ◽  
Mehdi Van den Bos ◽  
Parvathi Menon ◽  
Steve Vucic

Amyotrophic lateral sclerosis (ALS) is characterised by progressive dysfunction of the upper and lower motor neurons. The disease can evolve over time from focal limb or bulbar onset to involvement of other regions. There is some clinical heterogeneity in ALS with various phenotypes of the disease described, from primary lateral sclerosis, progressive muscular atrophy and flail arm/leg phenotypes. Whilst the majority of ALS patients are sporadic in nature, recent advances have highlighted genetic forms of the disease. Given the close relationship between ALS and frontotemporal dementia, the importance of cortical dysfunction has gained prominence. Transcranial magnetic stimulation (TMS) is a noninvasive neurophysiological tool to explore the function of the motor cortex and thereby cortical excitability. In this review, we highlight the utility of TMS and explore cortical excitability in ALS diagnosis, pathogenesis and insights gained from genetic and variant forms of the disease.


Diagnostics ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1210
Author(s):  
Júlia Costa ◽  
Marta Gromicho ◽  
Ana Pronto-Laborinho ◽  
Conceição Almeida ◽  
Ricardo A. Gomes ◽  
...  

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative neuromuscular disease that affects motor neurons controlling voluntary muscles. Survival is usually 2–5 years after onset, and death occurs due to respiratory failure. The identification of biomarkers would be very useful to help in disease diagnosis and for patient stratification based on, e.g., progression rate, with implications in therapeutic trials. Neurofilaments constitute already-promising markers for ALS and, recently, chitinases have emerged as novel marker targets for the disease. Here, we investigated cerebrospinal fluid (CSF) chitinases as potential markers for ALS. Chitotriosidase (CHIT1), chitinase-3-like protein 1 (CHI3L1), chitinase-3-like protein 2 (CHI3L2) and the benchmark marker phosphoneurofilament heavy chain (pNFH) were quantified by an enzyme-linked immunosorbent assay (ELISA) from the CSF of 34 ALS patients and 24 control patients with other neurological diseases. CSF was also analyzed by UHPLC-mass spectrometry. All three chitinases, as well as pNFH, were found to correlate with disease progression rate. Furthermore, CHIT1 was elevated in ALS patients with high diagnostic performance, as was pNFH. On the other hand, CHIT1 correlated with forced vital capacity (FVC). The three chitinases correlated with pNFH, indicating a relation between degeneration and neuroinflammation. In conclusion, our results supported the value of CHIT1 as a diagnostic and progression rate biomarker, and its potential as respiratory function marker. The results opened novel perspectives to explore chitinases as biomarkers and their functional relevance in ALS.


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