| 1. |
- Almandoz-Gil, Leire, et al.
(författare)
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Mapping of Surface-Exposed Epitopes of In Vitro and In Vivo Aggregated Species of Alpha-Synuclein
- 2017
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Ingår i: Cellular and molecular neurobiology. - : Springer Science and Business Media LLC. - 0272-4340 .- 1573-6830. ; 37:7, s. 1217-1226
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Tidskriftsartikel (refereegranskat)abstract
- Aggregated alpha-synuclein is the main component of Lewy bodies, intraneuronal deposits observed in Parkinson's disease and dementia with Lewy bodies. The objective of the study was to identify surface-exposed epitopes of alpha-synuclein in vitro and in vivo formed aggregates. Polyclonal immunoglobulin Y antibodies were raised against short linear peptides of the alpha-synuclein molecule. An epitope in the N-terminal region (1-10) and all C-terminal epitopes (90-140) were found to be exposed in an indirect enzyme-linked immunosorbent assay (ELISA) using recombinant monomeric, oligomeric, and fibrillar alpha-synuclein. In a phospholipid ELISA, the N-terminus and mid-region of alpha-synuclein (i.e., 1-90) were associated with phosphatidylserine and thus occluded from antibody binding. The antibodies that reacted most strongly with epitopes in the in vitro aggregates (i.e., 1-10 and epitopes between positions 90-140) also labeled alpha-synuclein inclusions in brains from transgenic (Thy-1)-h[A30P] alpha-synuclein mice and Lewy bodies and Lewy neurites in brains of patients with alpha-synucleinopathies. However, differences in reactivity were observed with the C-terminal antibodies when brain tissue from human and transgenic mice was compared. Taken together, the study shows that although similar epitopes are exposed in both in vitro and in vivo formed alpha-synuclein inclusions, structural heterogeneity can be observed between different molecular species.
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| 2. |
- Ekmark-Lewén, Sara, et al.
(författare)
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Early fine motor impairment and behavioral dysfunction in (Thy-1)-h[A30P] alpha-synuclein mice
- 2018
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Ingår i: Brain and Behavior. - : WILEY. - 2162-3279 .- 2162-3279. ; 8:3
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Intraneuronal inclusions of alpha-synuclein are commonly found in the brain of patients with Parkinson's disease and other a-synucleinopathies. The correlation between alpha-synuclein pathology and symptoms has been studied in various animal models. In (Thy-1)-h[A30P] alpha-synuclein transgenic mice, behavioral and motor abnormalities were reported from 12 and 15 months, respectively. The aim of this study was to investigate whether these mice also display symptoms at earlier time points.Methods: We analyzed gait deficits, locomotion, and behavioral profiles in (Thy-1)-h[A30P] alpha-synuclein and control mice at 2, 8, and 11 months of age. In addition, inflammatory markers, levels of alpha-synuclein oligomers, and tyrosine hydroxylase reactivity were studied.Results: Already at 2 months of age, transgenic mice displayed fine motor impairments in the challenging beam test that progressively increased up to 11 months of age. At 8 months, transgenic mice showed a decreased general activity with increased risk-taking behavior in the multivariate concentric square field test. Neuropathological analyses of 8- and 11-month-old mice revealed accumulation of oligomeric alpha-synuclein in neuronal cell bodies. In addition, a decreased presence of tyrosine hydroxylase suggests a dysregulation of the dopaminergic system in the transgenic mice, which in turn may explain some of the motor impairments observed in this mouse model.Conclusions: Taken together, our results show that the (Thy-1)-h[A30P] alpha-synuclein transgenic mouse model displays early Parkinson's disease-related symptoms with a concomitant downregulation of the dopaminergic system. Thus, this should be an -appropriate model to study early phenotypes of alpha-synucleinopathies.
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| 3. |
- Fagerqvist, Therese, et al.
(författare)
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Monoclonal antibodies selective for α-synuclein oligomers/protofibrils recognize brain pathology in Lewy body disorders and α-synuclein transgenic mice with the disease-causing A30P mutation
- 2013
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Ingår i: Journal of Neurochemistry. - : Wiley-Blackwell. - 0022-3042 .- 1471-4159. ; 126:1, s. 131-144
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Tidskriftsartikel (refereegranskat)abstract
- Inclusions of intraneuronal alpha-synuclein (-synuclein) can be detected in brains of patients with Parkinson's disease and dementia with Lewy bodies. The aggregation of -synuclein is a central feature of the disease pathogenesis. Among the different -synuclein species, large oligomers/protofibrils have particular neurotoxic properties and should therefore be suitable as both therapeutic and diagnostic targets. Two monoclonal antibodies, mAb38F and mAb38E2, with high affinity and strong selectivity for large -synuclein oligomers were generated. These antibodies, which do not bind amyloid-beta or tau, recognize Lewy body pathology in brains from patients with Parkinson's disease and dementia with Lewy bodies and detect pathology earlier in -synuclein transgenic mice than linear epitope antibodies. An oligomer-selective sandwich ELISA, based on mAb38F, was set up to analyze brain extracts of the transgenic mice. The overall levels of -synuclein oligomers/protofibrils were found to increase with age in these mice, although the levels displayed a large interindividual variation. Upon subcellular fractionation, higher levels of -synuclein oligomers/protofibrils could be detected in the endoplasmic reticulum around the age when behavioral disturbances develop. In summary, our novel oligomer-selective -synuclein antibodies recognize relevant pathology and should be important tools to further explore the pathogenic mechanisms in Lewy body disorders. Moreover, they could be potential candidates both for immunotherapy and as reagents in an assay to assess a potential disease biomarker.
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| 4. |
- Fagerqvist, Therese, et al.
(författare)
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Off-pathway alpha-synuclein oligomers seem to alter alpha-synuclein turnover in a cell model but lack seeding capability in vivo
- 2013
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Ingår i: Amyloid. - : Informa UK Limited. - 1350-6129 .- 1744-2818. ; 20:4, s. 233-244
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Tidskriftsartikel (refereegranskat)abstract
- Aggregated α-synuclein is the major component of Lewy bodies, protein inclusions observed in the brain in neurodegenerative disorders such as Parkinson’s disease and dementia with Lewy bodies. Experimental evidence indicates that α-synuclein potentially can be transferred between cells and act as a seed to accelerate the aggregation process. Here, we investigated in vitro and in vivo seeding effects of α-synuclein oligomers induced by the reactive aldehyde 4-oxo-2-nonenal (ONE). As measured by a Thioflavin-T based fibrillization assay, there was an earlier onset of aggregation when α-synuclein oligomers were added to monomeric α-synuclein. In contrast, exogenously added α-synuclein oligomers did not induce aggregation in a cell model. However, cells overexpressing α-synuclein that were treated with the oligomers displayed reduced α-synuclein levels, indicating that internalized oligomers either decreased the expression or accelerated the degradation of transfected α-synuclein. Also in vivo there were no clear seeding effects, as intracerebral injections of α-synuclein oligomers into the neocortex of α-synuclein transgenic mice did not induce formation of Proteinase K resistant α-synuclein pathology. Taken together, we could observe a seeding effect of the ONE-induced α-synuclein oligomers in a fibrillization assay, but neither in a cell nor in a mouse model.
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| 5. |
- Fagerqvist, Therese, et al.
(författare)
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Off-pathway α-synuclein oligomers seem to alter α-synuclein turnover in a cell model but lack seeding capability in vivo
- 2013
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Ingår i: Amyloid. - : Informa Healthcare. - 1350-6129 .- 1744-2818. ; 20:4, s. 233-244
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Tidskriftsartikel (refereegranskat)abstract
- Aggregated alpha-synuclein is the major component of Lewy bodies, protein inclusions observed in the brain in neurodegenerative disorders such as Parkinson's disease and dementia with Lewy bodies. Experimental evidence indicates that alpha-synuclein potentially can be transferred between cells and act as a seed to accelerate the aggregation process. Here, we investigated in vitro and in vivo seeding effects of alpha-synuclein oligomers induced by the reactive aldehyde 4-oxo-2-nonenal (ONE). As measured by a Thioflavin-T based fibrillization assay, there was an earlier onset of aggregation when alpha-synuclein oligomers were added to monomeric alpha-synuclein. In contrast, exogenously added alpha-synuclein oligomers did not induce aggregation in a cell model. However, cells overexpressing alpha-synuclein that were treated with the oligomers displayed reduced alpha-synuclein levels, indicating that internalized oligomers either decreased the expression or accelerated the degradation of transfected alpha-synuclein. Also in vivo there were no clear seeding effects, as intracerebral injections of alpha-synuclein oligomers into the neocortex of alpha-synuclein transgenic mice did not induce formation of proteinase K resistant alpha-synuclein pathology. Taken together, we could observe a seeding effect of the ONE-induced alpha-synuclein oligomers in a fibrillization assay, but neither in a cell nor in a mouse model.
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| 6. |
- Lindström, Veronica, et al.
(författare)
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Immunotherapy targeting α-synuclein protofibrils reduced pathology in (Thy-1)-h[A30P] α-synuclein mice
- 2014
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Ingår i: Neurobiology of Disease. - : Elsevier BV. - 0969-9961 .- 1095-953X. ; 69, s. 134-143
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Tidskriftsartikel (refereegranskat)abstract
- Several lines of evidence suggest that accumulation of aggregated alpha-synuclein (α-synuclein) in the central nervous system (CNS) is an early pathogenic event and therefore a suitable therapeutic target in Parkinson’s disease and other Lewy body disorders. In recent years, animal studies have indicated immunotherapy with antibodies directed against α-synuclein as a promising novel treatment strategy. Since large α-synuclein oligomers, or protofibrils, have been demonstrated to possess pronounced cytotoxic properties, such species should be particularly attractive as therapeutic targets. An α-synuclein protofibril-selective monoclonal antibody, mAb47, was evaluated in the (Thy-1)-h[A30P] α-synuclein transgenic mouse model, featuring an age- and motor dysfunction-associated increase of α-synuclein protofibrils in the CNS. As measured by ELISA, mAb47-treated mice displayed significantly lower levels of both soluble and membrane-associated protofibrils in the spinal cord. In addition, a trend for increased survival as a result of reduced motor symptoms was observed with antibody treatment. Taken together, this study demonstrates reduced levels of pathogenic α-synuclein and indicates a reduction of motor dysfunction in transgenic mice upon peripheral administration of an α-synuclein protofibril-selective antibody. Thus, immunotherapy with antibodies targeting toxic α-synuclein species holds promise as a future disease-modifying treatment in Parkinson’s disease and related disorders.
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| 7. |
- Tanrioever, Gaye, et al.
(författare)
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Prominent microglial inclusions in transgenic mouse models of alpha-synucleinopathy that are distinct from neuronal lesions
- 2020
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Ingår i: Acta neuropathologica communications. - : BMC. - 2051-5960. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Alpha-synucleinopathies are a group of progressive neurodegenerative disorders, characterized by intracellular deposits of aggregated alpha-synuclein (alpha S). The clinical heterogeneity of these diseases is thought to be attributed to conformers (or strains) of alpha S but the contribution of inclusions in various cell types is unclear. The aim of the present work was to study alpha S conformers among different transgenic (TG) mouse models of alpha-synucleinopathies. To this end, four different TG mouse models were studied (Prnp-h[A53T]alpha S; Thy1-h[A53T]alpha S; Thy1-h[A30P]alpha S; Thy1-m alpha S) that overexpress human or murine alpha S and differed in their age-of-symptom onset and subsequent disease progression. Postmortem analysis of end-stage brains revealed robust neuronal alpha S pathology as evidenced by accumulation of alpha S serine 129 (p-alpha S) phosphorylation in the brainstem of all four TG mouse lines. Overall appearance of the pathology was similar and only modest differences were observed among additionally affected brain regions. To study alpha S conformers in these mice, we used pentameric formyl thiophene acetic acid (pFTAA), a fluorescent dye with amyloid conformation-dependent spectral properties. Unexpectedly, besides the neuronal alpha S pathology, we also found abundant pFTAA-positive inclusions in microglia of all four TG mouse lines. These microglial inclusions were also positive for Thioflavin S and showed immunoreactivity with antibodies recognizing the N-terminus of alpha S, but were largely p-alpha S-negative. In all four lines, spectral pFTAA analysis revealed conformational differences between microglia and neuronal inclusions but not among the different mouse models. Concomitant with neuronal lesions, microglial inclusions were already present at presymptomatic stages and could also be induced by seeded alpha S aggregation. Although nature and significance of microglial inclusions for human alpha-synucleinopathies remain to be clarified, the previously overlooked abundance of microglial inclusions in TG mouse models of alpha-synucleinopathy bears importance for mechanistic and preclinical-translational studies.
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