Uptake of alpha-synuclein preformed fibrils is suppressed by inflammation and induces an aberrant phenotype in human microglia
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE277636 | GEO | 2024/10/22
REPOSITORIES: GEO
Similar Datasets
Project description:Synucleinopathies are triggered by the aggregation of α-synuclein (αSyn), leading to progressive neurodegeneration. However, the intracellular mechanism of αSyn aggregation remains unclear. Here we show that assembly of RNA G-quadruplexes (rG4s) form scaffolds for αSyn aggregation, contributing to neurodegeneration. Purified αSyn binds rG4s directly through the N-terminus. rG4 itself undergoes phase separation and assembly by Ca2+, accelerating the sol-gel phase transition of αSyn. In αSyn preformed fibrils (PFF)-treated neurons, rG4s assembly composed of synaptic mRNAs co-aggregates with αSyn upon Ca2+ excess influx into cytoplasm, eliciting synaptic dysfunction. Artificial assembly of rG4s using an optogenetic approach evokes αSyn aggregation and neuronal dysfunction. Administration of 5-aminolevulinic acid (5-ALA), a prodrug of protoporphyrin IX (PpIX) that prevents phase separation of rG4s, attenuating αSyn aggregation, neurodegeneration, and progressive motor deficits in PFF-injected synucleinopathy mice. Together, assembly of rG4s due to dysregulation of intracellular Ca2+ homeostasis accelerates αSyn phase transition and aggregation may contribute to pathogenesis of synucleinopathies.
2023-07-18 | GSE234238 | GEO
Project description:Uptake of alpha-synuclein preformed fibrils is suppressed by inflammation and induces an aberrant phenotype in human microglia
| PRJNA1163099 | ENA
Project description:Transcriptomic Profiling of Early Synucleinopathy in Rats Induced with Preformed Fibrils
| PRJNA1031579 | ENA
Project description:Parkinson’s disease (PD) is a neurodegenerative disease characterized by progressive motor symptoms and alpha-synuclein (αsyn) aggregation in the nervous system. For unclear reasons, PD patients with certain GBA mutations (GBA-PD) have a more aggressive clinical progression. Two testable hypotheses that can potentially account for this phenomenon are that GBA1 mutations promote αsyn spread or drive the generation of highly pathogenic αsyn polymorphs (i.e., strains). We tested these hypotheses by treating homozygous GBA1 D409V knockin (KI) mice with human α-syn-preformed fibrils (PFFs) and treating wild-type mice (WT) with several αsyn-PFF polymorphs amplified from brain autopsy samples collected from patients with idiopathic PD and GBA-PD patients with either homozygous or heterozygous GBA1 mutations. Robust phosphorylated-αsyn (PSER129) positive pathology was observed at the injection site (i.e., the olfactory bulb granular layer) and throughout the brain six months following PFF injection. The PFF seeding efficiency and degree of spread were similar regardless of the mouse genotype or PFF polymorphs. We found that PFFs amplified from the human brain, regardless of patient genotype, were generally more effective seeders than wholly synthetic PFFs (i.e., non-amplified); however, PFF concentration differed between these two studies, and this might also account for the observed differences. To investigate whether the molecular composition of pathology differed between different seeding conditions, we permed Biotinylation by Antibody Recognition on PSER129 (BAR-PSER129). We found that for BAR-PSER129, the endogenous PSER129 pool dominated identified interactions, and thus, very few potential interactions were explicitly identified for seeded pathology. However, we found Dctn2 interaction was shared across all PFF conditions, and Nckap1 and Ap3b2 were unique to PFFs amplified from GBA-PD brains of heterozygous mutation carriers. In conclusion, both the genotype and αsyn strain had little effect on overall seeding efficacy and global PSER129-interactions.
2024-02-22 | PXD045437 | Pride
Project description:Emerging evidence indicates that cellular senescence could be a critical inducing factor for aging-associated neurodegenerative disorders. However, the involvement of cellular senescence remains unclear in Parkinson's disease (PD). To determine this, we assessed the effects of α-synuclein preformed fibrils (α-syn PFF) or 1-methyl-4-phenylpyridinium (MPP+) on changes in cellular senescence markers, employing α-syn PFF treated-dopaminergic N27 cells, primary cortical neurons, astrocytes and microglia and α-syn PFF-injected mouse brain tissues, as well as human PD patient brains. Our results demonstrate that α-syn PFF-induced toxicity reduces the levels of Lamin B1 and HMGB1, both established markers of cellular senescence, in correlation with an increase in the levels of p21, a cell cycle-arrester and senescence marker, in both reactive astrocytes and microglia in mouse brains. Using Western blot and immunohistochemistry, we found these cellular senescence markers in reactive astrocytes as indicated by enlarged cell bodies within GFAP-positive cells and Iba1-positive activated microglia in α-syn PFF injected mouse brains. These results indicate that PFF-induced pathology could lead to astrocyte and/or microglia senescence in PD brains, which may contribute to neuropathology in this model. Targeting senescent cells using senolytics could therefore constitute a viable therapeutic option for the treatment of PD.
| S-EPMC8304385 | biostudies-literature
Project description:The overall goal was to identify changes in gene expression following treatment with aSYN F110 compared to control (untreated). Alpha-synuclein (αSYN) protein has been observed in reactive astrocytes in PD patients’ brains, raising the question of how αSYN, neuroinflammation, and astrocytes interact in PD pathogenesis. Here, we examined the cellular changes triggered by tumor necrosis factor alpha (TNFα) and different αSYN species in astrocytes derived from induced pluripotent stem cells. Human astrocytes treated with TNFα displayed a strong reactive pro-inflammatory phenotype with upregulation of pro-inflammatory gene networks, activation of the NF-kB pathway, and release of pro-inflammatory cytokines, whereas those treated with high molecular weight αSYN fibrils acquired a reactive antigen (cross-)presenting phenotype with upregulation of MHC genes and increased HLA-DR/DQ/DP and HLA-F molecules at the cell surface. Surprisingly, cell surface location of MHC proteins was abrogated by larger F110 fibrils polymorph, despite the upregulation of MHC genes. A proteomics investigation further confirmed a direct interaction between astrocytic MHC proteins and αSYN fibril peptides. Interestingly, TNFα and αSYN fibrils competed to drive the astrocyte immune reactive response. The astrocyte immune responses were accompanied by an impaired ATP-generating mitochondrial respiration, which was exacerbated in PD astrocytes containing a PARK2-variant. Our data provide evidence for astrocytic involvement in PD pathogenesis and reveal their complex immune reactive responses to exogenous stressors.
2021-02-16 | GSE166769 | GEO
Project description:Parkinson's disease (PD) is a neurodegenerative disorder characterized by the aggregation of misfolded α-synuclein and progressive spreading of the aggregates from a few discrete regions to wider brain regions. Although PD has been classically considered a movement disorder, a large body of clinical evidence has revealed the progressive occurrence of non-motor symptoms. Patients present visual symptoms in the initial stages of the disease, and accumulation of phospho-α-synuclein, dopaminergic neuronal loss, and retinal thinning has been observed in the retinas of PD patients. Based on such human data, we hypothesized that α-synuclein aggregation can initiate in the retina and spread to the brain through the visual pathway. Here, we demonstrate accumulation of α-synuclein in the retinas and brains of naive mice after intravitreal injection of α-synuclein preformed fibrils (PFFs). Histological analyses showed deposition of phospho-α-synuclein inclusions within the retina 2 months after injection, with increased oxidative stress leading to loss of retinal ganglion cells and dopaminergic dysfunction. In addition, we found accumulation of phospho-α-synuclein in cortical areas with accompanying neuroinflammation after 5 months. Collectively, our findings suggest that retinal synucleinopathy lesions initiated by intravitreal injection of α-synuclein PFFs spread to various brain regions through the visual pathway in mice.
| S-EPMC10199563 | biostudies-literature
Project description:The overall goal was to identify changes in gene expression following treatment with TNFa, monomeric, or fibril aSYN compared to control (untreated). Alpha-synuclein (αSYN) protein has been observed in reactive astrocytes in PD patients’ brains, raising the question of how αSYN, neuroinflammation, and astrocytes interact in PD pathogenesis. Here, we examined the cellular changes triggered by tumor necrosis factor alpha (TNFα) and different αSYN species in astrocytes derived from induced pluripotent stem cells. Human astrocytes treated with TNFα displayed a strong reactive pro-inflammatory phenotype with upregulation of pro-inflammatory gene networks, activation of the NF-kB pathway, and release of pro-inflammatory cytokines, whereas those treated with high molecular weight αSYN fibrils acquired a reactive antigen (cross-)presenting phenotype with upregulation of MHC genes and increased HLA-DR/DQ/DP and HLA-F molecules at the cell surface. Surprisingly, cell surface location of MHC proteins was abrogated by larger F110 fibrils polymorph, despite the upregulation of MHC genes. A proteomics investigation further confirmed a direct interaction between astrocytic MHC proteins and αSYN fibril peptides. Interestingly, TNFα and αSYN fibrils competed to drive the astrocyte immune reactive response. The astrocyte immune responses were accompanied by an impaired ATP-generating mitochondrial respiration, which was exacerbated in PD astrocytes containing a PARK2-variant. Our data provide evidence for astrocytic involvement in PD pathogenesis and reveal their complex immune reactive responses to exogenous stressors.
2021-02-16 | GSE166768 | GEO
Project description:Examination of early phases of synucleinopathy when inclusions are present, but long before neurodegeneration occurs, is critical to both understanding disease progression and the development of disease modifying therapies. The rat alpha-synuclein (α-syn) preformed fibril (PFF) model induces synchronized synucleinopathy that recapitulates the pathological features of Parkinson’s disease (PD) and can be used to study synucleinopathy progression. In this model, phosphorylated α-syn (pSyn) inclusion-containing neurons and reactive microglia (major histocompatibility complex-II immunoreactive) peak in the substantia nigra pars compacta (SNpc) months before appreciable neurodegeneration. However, it remains unclear which specific genes are driving these phenotypic changes. To identify transcriptional changes associated with early synucleinopathy, we used laser capture microdissection of the SNpc paired with RNA sequencing (RNASeq). Precision collection of the SNpc allowed for the assessment of differential transcript expression in the nigral dopamine neurons and proximal glia. Transcripts upregulated in early synucleinopathy were mainly associated with an immune response, whereas transcripts downregulated were associated with neurotransmission and the dopamine pathway. A subset of 29 transcripts associated with neurotransmission/vesicular release and the dopamine pathway were verified in a separate cohort of males and females to confirm reproducibility. Within this subset, fluorescent in situ hybridization (FISH) was used to localize decreases in the Syt1 and Slc6a3 transcripts to pSyn inclusion-containing neurons. Identification of transcriptional changes in early synucleinopathy provides insight into the molecular mechanisms driving neurodegeneration.
2023-10-24 | GSE246112 | GEO
Project description:BackgroundSynucleinopathy is a group of neurodegenerative disorders characterized by neurodegeneration and accumulation of alpha-synuclein (α-syn) aggregates in various brain regions. The detailed mechanism of α-syn-caused neurotoxicity remains obscure, which is partly due to the lack of a suitable model that retains the in vivo three-dimensional cellular network and allows a convenient dissection of the neurotoxic pathways. Recent studies revealed that the pre-formed recombinant α-syn amyloid fibrils (PFFs) induce a robust accumulation of pathogenic α-syn species in cultured cells and animals.ObjectiveOur goal is to determine whether PFFs are able to induce the pathogenic α-syn accumulation and neurotoxicity in organotypic brain slice culture, an ex vivo system that retains the in vivo three-dimensional cell-cell connections.Methods/resultsAdding PFFs to cultured wild-type rat or mouse brain slices induced a time-dependent accumulation of pathogenic α-syn species, which was indicated by α-syn phosphorylated at serine 129 (pα-syn). The PFF-induced pα-syn was abolished in brain slices prepared from α-syn null mice, suggesting that the pα-syn is from the phosphorylation of endogenous α-syn. Human PFFs also induced pα-syn in brain slices prepared from mice expressing human α-syn on a mouse α-syn-null background. Furthermore, the synaptophysin immunoreactivity was inversely associated with pα-syn accumulation and an increase of neuronal loss was detected.ConclusionPFF-treatment of brain slices is able to induce key pathological features of synucleinopathy: pα-syn accumulation and neurotoxicity. This model will be useful for investigating the neurotoxic mechanism and evaluating efficacy of therapeutic approaches.
| S-EPMC7683096 | biostudies-literature