| 1. |
- Freischmidt, Axel, et al.
(författare)
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A serum microRNA sequence reveals fragile X protein pathology in amyotrophic lateral sclerosis
- 2021
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Ingår i: Brain. - : Oxford University Press. - 0006-8950 .- 1460-2156. ; 144:4, s. 1214-1229
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge about converging disease mechanisms in the heterogeneous syndrome amyotrophic lateral sclerosis (ALS) is rare, but may lead to therapies effective in most ALS cases. Previously, we identified serum microRNAs downregulated in familial ALS, the majority of sporadic ALS patients, but also in presymptomatic mutation carriers. A 5-nucleotide sequence motif (GDCGG; D = G, A or U) was strongly enriched in these ALS-related microRNAs. We hypothesized that deregulation of protein(s) binding predominantly to this consensus motif was responsible for the ALS-linked microRNA fingerprint. Using microRNA pull-down assays combined with mass spectrometry followed by extensive biochemical validation, all members of the fragile X protein family, FMR1, FXR1 and FXR2, were identified to directly and predominantly interact with GDCGG microRNAs through their structurally disordered RGG/RG domains. Preferential association of this protein family with ALS-related microRNAs was confirmed by in vitro binding studies on a transcriptome-wide scale. Immunohistochemistry of lumbar spinal cord revealed aberrant expression level and aggregation of FXR1 and FXR2 in C9orf72- and FUS-linked familial ALS, but also patients with sporadic ALS. Further analysis of ALS autopsies and induced pluripotent stem cell-derived motor neurons with FUS mutations showed co-aggregation of FXR1 with FUS. Hence, our translational approach was able to take advantage of blood microRNAs to reveal CNS pathology, and suggests an involvement of the fragile X-related proteins in familial and sporadic ALS already at a presymptomatic stage. The findings may uncover disease mechanisms relevant to many patients with ALS. They furthermore underscore the systemic, extra-CNS aspect of ALS.
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| 2. |
- Yilmaz, Rüstem, et al.
(författare)
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SQSTM1/p62 variants in 486 patients with familial ALS from Germany and Sweden
- 2020
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Ingår i: Neurobiology of Aging. - : ELSEVIER SCIENCE INC. - 0197-4580 .- 1558-1497. ; 87, s. 139.e9-139.e15
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Tidskriftsartikel (refereegranskat)abstract
- Several studies reported amyotrophic lateral sclerosis (ALS)-linked mutations in TBK1, OPTN, VCP, UBQLN2, and SQSTM1 genes encoding proteins involved in autophagy. SQSTM1 was originally identified by a candidate gene approach because it encodes p62, a multifunctional protein involved in protein degradation both through proteasomal regulation and autophagy. Both p62 and optineurin (encoded by OPTN) are direct interaction partners and substrates of TBK1, and these 3 proteins form the core of a genetic and functional network that may connect autophagy with ALS. Considering the molecular and conceptual relevance of the TBK1/OPTN/SQSTM1 "triangle," we here performed a targeted screen for SQSTM1 variants in 486 patients with familial ALS from Germany and Sweden by analyzing whole-exome sequencing data. We report 9 novel and 5 previously reported rare variants in SQSTM1 and discuss the current evidence for SQSTM1 as a primary disease gene for ALS. We conclude that the evidence for causality remains vague for SQSTM1 and is weaker than for the other autophagy genes, for example, TBK1 and OPTN.
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| 3. |
- Zimyanin, Vitaly L., et al.
(författare)
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Live cell imaging of ATP levels reveals metabolic compartmentalization within motoneurons and early metabolic changes in FUS ALS motoneurons
- 2023
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Ingår i: Cells. - : MDPI. - 2073-4409. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- Motoneurons are one of the most energy-demanding cell types and a primary target in Amyotrophic lateral sclerosis (ALS), a debilitating and lethal neurodegenerative disorder without currently available effective treatments. Disruption of mitochondrial ultrastructure, transport, and metabolism is a commonly reported phenotype in ALS models and can critically affect survival and the proper function of motor neurons. However, how changes in metabolic rates contribute to ALS progression is not fully understood yet. Here, we utilize hiPCS-derived motoneuron cultures and live imaging quantitative techniques to evaluate metabolic rates in fused in sarcoma (FUS)-ALS model cells. We show that differentiation and maturation of motoneurons are accompanied by an overall upregulation of mitochondrial components and a significant increase in metabolic rates that correspond to their high energy-demanding state. Detailed compartment-specific live measurements using a fluorescent ATP sensor and FLIM imaging show significantly lower levels of ATP in the somas of cells carrying FUS-ALS mutations. These changes lead to the increased vulnerability of diseased motoneurons to further metabolic challenges with mitochondrial inhibitors and could be due to the disruption of mitochondrial inner membrane integrity and an increase in its proton leakage. Furthermore, our measurements demonstrate heterogeneity between axonal and somatic compartments, with lower relative levels of ATP in axons. Our observations strongly support the hypothesis that mutated FUS impacts the metabolic states of motoneurons and makes them more susceptible to further neurodegenerative mechanisms.
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| 4. |
- Andersen, Peter M., 1962-, et al.
(författare)
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Therapeutic decisions in ALS patients : cross-cultural differences and clinical implications
- 2018
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Ingår i: Journal of Neurology. - : Springer Berlin/Heidelberg. - 0340-5354 .- 1432-1459. ; 265:7, s. 1600-1606
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Quantitative analysis of decision-making on therapeutic options in different sociocultural context in amyotrophic lateral sclerosis (ALS).Methods: ALS patients (n = 244) were consecutively recruited in Germany (n = 83), Poland (n = 83), and Sweden (n = 78) in a prospective cross-cultural study (www.NEEDSinALS.com). They were interviewed on preferences for therapeutic techniques including invasive (IV) and non-invasive ventilation (NIV), as well as percutaneous endoscopic gastrostomy (PEG) and on hypothetical termination of these using quantitative questions. Using standardized questionnaires, religiousness, personal values, quality of life, and depressiveness were assessed.Results: NIV was most frequently used in Germany and PEG in Sweden. Swedish patients were most liberal on initiation and termination of PEG, NIV and IV. Polish patients were mostly undecided and were least likely to consider discontinuing supportive management. Current use was partly associated with age, gender and state of physical function; also, financial support explained some variance. Future preferences on therapeutic options from the patient’s perspective were also closely associated with cultural factors. The more oriented towards traditional and conservative values, the less likely patients were to decide for invasive therapeutic devices (IV, PEG), the least likely to have ideations to discontinue any device and the more likely to have an undecided attitude.Conclusions: Current use of therapeutic options is determined by medical condition in analogy to clinical guidelines. For future considerations, other factors such as cultural background are crucial, yielding hurdles to be regarded in the implementation of advanced directives in a multicultural environment.
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| 5. |
- Günther, René, et al.
(författare)
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Alteration of Mitochondrial Integrity as Upstream Event in the Pathophysiology of SOD1-ALS
- 2022
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Ingår i: Cells. - : MDPI. - 2073-4409. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- Little is known about the early pathogenic events by which mutant superoxide dismutase 1 (SOD1) causes amyotrophic lateral sclerosis (ALS). This lack of mechanistic understanding is a major barrier to the development and evaluation of efficient therapies. Although protein aggregation is known to be involved, it is not understood how mutant SOD1 causes degeneration of motoneurons (MNs). Previous research has relied heavily on the overexpression of mutant SOD1, but the clinical relevance of SOD1 overexpression models remains questionable. We used a human induced pluripotent stem cell (iPSC) model of spinal MNs and three different endogenous ALS-associated SOD1 mutations (D90Ahom, R115Ghet or A4Vhet) to investigate early cellular disturbances in MNs. Although enhanced misfolding and aggregation of SOD1 was induced by proteasome inhibition, it was not affected by activation of the stress granule pathway. Interestingly, we identified loss of mitochondrial, but not lysosomal, integrity as the earliest common pathological phenotype, which preceded elevated levels of insoluble, aggregated SOD1. A super-elongated mitochondrial morphology with impaired inner mitochondrial membrane potential was a unifying feature in mutant SOD1 iPSC-derived MNs. Impaired mitochondrial integrity was most prominent in mutant D90Ahom MNs, whereas both soluble disordered and detergent-resistant misfolded SOD1 was more prominent in R115Ghet and A4Vhet mutant lines. Taking advantage of patient-specific models of SOD1-ALS in vitro, our data suggest that mitochondrial dysfunction is one of the first crucial steps in the pathogenic cascade that leads to SOD1-ALS and also highlights the need for individualized medical approaches for SOD1-ALS.
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| 6. |
- Naumann, Marcel, et al.
(författare)
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Phenotypes and malignancy risk of different FUS mutations in genetic amyotrophic lateral sclerosis
- 2019
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Ingår i: Annals of Clinical and Translational Neurology. - : John Wiley & Sons. - 2328-9503. ; 6:12, s. 2384-2394
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Mutations in Fused in Sarcoma (FUS or TLS) are the fourth most prevalent in Western European familial amyotrophic lateral sclerosis (ALS) populations and have been associated with causing both early and very late disease onset. FUS aggregation, DNA repair deficiency, and genomic instability are contributors to the pathophysiology of FUS-ALS, but their clinical significance per se and their influence on the clinical variability have yet to be sufficiently investigated. The aim of this study was to analyze genotype-phenotype correlations and malignancy rates in a newly compiled FUS-ALS cohort.Methods: We cross-sectionally reviewed FUS-ALS patient histories in a multicenter cohort with 36 novel cases and did a meta-analysis of published FUS-ALS cases reporting the largest genotype-phenotype correlation of FUS-ALS.Results: The age of onset (median 39 years, range 11-80) was positively correlated with the disease duration. C-terminal domain mutations were found in 90%. Among all, P525L and truncating/ frameshift mutations most frequently caused juvenile onset, rapid disease progression, and atypical ALS often associated with negative family history while the R521 mutation site was associated with late disease onset and pure spinal phenotype. Malignancies were found in one of 40 patients.Interpretation: We report the largest genotype-phenotype correlation of FUS-ALS, which enables a careful prediction of the clinical course in newly diagnosed patients. In this cohort, FUS-ALS patients did not have an increased risk for malignant diseases.
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