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- Lang, Lisa, 1973-
(author)
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SOD1 Aggregation : Relevance of thermodynamic stability
- 2017
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Doctoral thesis (other academic/artistic)abstract
- Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting the upper and lower motor neurons causing muscle atrophy and paralysis followed by death. Aggregates containing superoxide dismutase (SOD1) are found as pathological hallmark in diseased ALS patients. Consequently ALS is regarded as a protein misfolding disorder like Alzheimer’s disease and Parkinson’s disease. So far, little is known about the cause and mechanism behind SOD1 aggregation but the inherent property of all polypeptide chains to form stable aggregated structures indicates that the protein misfolding diseases share a common mechanism.Our results show that SOD1 aggregation starts from the globally unfolded state, since fibrillation is fastest at full occupancy of denatured protein induced either by chemical denaturation or mutation. Even so, the fibrillation rate shows a surprisingly weak dependence on the concentration of globally unfolded SOD1 indicating fibril fragmentation as the dominant mechanism for aggregate formation. This is further supported by the observation that the SOD1 sample has to be mechanically agitated for fibrillation to occur. Interestingly, we observe a similar SOD1 aggregation behaviour in vivo, where the survival times of ALS transgenic mice correlates with mutant stability, and aggregate growth depends weekly on the concentration of unfolded monomer. Additionally, in-cell NMR measurements reveal that in live cells the thermodynamic equilibrium is shifted towards the unfolded state of SOD1, which is also more fully extended than in vitro. This suggests that the globally unfolded aggregation competent protein is more abundant in the crowded environment in vivo than dilute in vitro conditions. Finally, antibody analysis of aggregates from ALS transgenic mice reveals the existence of aggregate strains involving different parts of the protein depending on mutation, which may offer an explanation for the various disease phenotypes observed in ALS. Altogether these findings provide important clues for understanding SOD1 aggregation with implications for ALS, as well as other protein misfolding diseases.
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| 2. |
- Lauque, Dominique, et al.
(author)
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Length-of-Stay in the Emergency Department and In-Hospital Mortality : A Systematic Review and Meta-Analysis
- 2022
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In: Journal of Clinical Medicine. - : MDPI. - 2077-0383. ; 12:1
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Research review (peer-reviewed)abstract
- The effect of emergency department (ED) length of stay (EDLOS) on in-hospital mortality (IHM) remains unclear. The aim of this systematic review and meta-analysis was to determine the association between EDLOS and IHM. We searched the PubMed, Medline, Embase, Web of Science, Cochrane Controlled Register of Trials, CINAHL, PsycInfo, and Scopus databases from their inception until 14-15 January 2022. We included studies reporting the association between EDLOS and IHM. A total of 11,337 references were identified, and 52 studies (total of 1,718,518 ED patients) were included in the systematic review and 33 in the meta-analysis. A statistically significant association between EDLOS and IHM was observed for EDLOS over 24 h in patients admitted to an intensive care unit (ICU) (OR = 1.396, 95% confidence interval [CI]: 1.147 to 1.701; p < 0.001, I2 = 0%) and for low EDLOS in non-ICU-admitted patients (OR = 0.583, 95% CI: 0.453 to 0.745; p < 0.001, I2 = 0%). No associations were detected for the other cut-offs. Our findings suggest that there is an association between IHM low EDLOS and EDLOS exceeding 24 h and IHM. Long stays in the ED should not be allowed and special attention should be given to patients admitted after a short stay in the ED.
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| 3. |
- Nordström, Ulrika, et al.
(author)
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Mutant SOD1 aggregates formed in vitro and in cultured cells are polymorphic and differ from those arising in the CNS
- 2023
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In: Journal of Neurochemistry. - : John Wiley & Sons. - 0022-3042 .- 1471-4159. ; 164:1, s. 77-93
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Journal article (peer-reviewed)abstract
- Mutations in the human Superoxide dismutase 1 (hSOD1) gene are well-established cause of the motor neuron disease ALS. Patients and transgenic (Tg) ALS model mice carrying mutant variants develop hSOD1 aggregates in the CNS. We have identified two hSOD1 aggregate strains, which both transmit spreading template-directed aggregation and premature fatal paralysis when inoculated into adult transgenic mice. This prion-like spread of aggregation could be a primary disease mechanism in SOD1-induced ALS. Human SOD1 aggregation has been studied extensively both in cultured cells and under various conditions in vitro. To determine how the structure of aggregates formed in these model systems related to disease-associated aggregates in the CNS, we used a binary epitope-mapping assay to examine aggregates of hSOD1 variants G93A, G85R, A4V, D90A, and G127X formed in vitro, in four different cell lines and in the CNS of Tg mice. We found considerable variability between replicate sets of in vitro-generated aggregates. In contrast, there was a high similarity between replicates of a given hSOD1 mutant in a given cell line, but pronounced variations between different hSOD1 mutants and different cell lines in both structures and amounts of aggregates formed. The aggregates formed in vitro or in cultured cells did not replicate the aggregate strains that arise in the CNS. Our findings suggest that the distinct aggregate morphologies in the CNS could result from a micro-environment with stringent quality control combined with second-order selection by spreading ability. Explorations of pathogenesis and development of therapeutics should be conducted in models that replicate aggregate structures forming in the CNS. (Figure presented.)
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