Synaptic decline precedes dopaminergic neuronal loss in human midbrain organoids harboring a triplication of the SNCA gene
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE278265 | GEO | 2024/12/02
REPOSITORIES: GEO
Similar Datasets
Project description:Aggregated α-synuclein (α-SYN) proteins, encoded by the SNCA gene, are hallmarks of Lewy body disease (LBD), affecting multiple brain regions. However, the specific mechanisms underlying α-SYN pathology in cortical neurons, crucial for LBD-associated dementia, remain unclear. Here, we generated human cortical LBD models by differentiating induced pluripotent stem cells (iPSCs) from SNCA triplication LBD patients into cerebral organoids and observed increased levels of pathological α-SYN in these organoids. Single-cell RNA sequencing revealed prominent expression of the SNCA gene in excitatory neurons, which exhibited synaptic and mitochondrial dysfunction, consistent with findings in the cortex of LBD human brains. Furthermore, screening 1280 FDA-approved drugs identified four candidates, which inhibited α-SYN seeding in RT-QuIC assay, reduced α-SYN aggregation and alleviated mitochondrial dysfunction in SNCA triplication iPSC models. Our findings provide valuable insights into the development of cortical LBD models and the discovery of potential drugs targeting α-SYN aggregation.
2024-09-18 | GSE236002 | GEO
Project description:Parkinson’s disease (PD) is a prevalent neurodegenerative disorder that is characterized by the selective loss of midbrain dopamine (DA)-producing neurons and the formation of α-synuclein (α-syn)-containing inclusions named Lewy bodies (LBs). Here, we report that the loss of glucocerebrosidase (GCase), coupled with α-syn overexpression, result in substantial accumulation of detergent-resistant α-syn aggregates and Lewy body-like inclusions (LBLIs) in human midbrain-like organoids (hMLOs). These LBLIs exhibit a highly similar structure to PD-associated LBs, by displaying a spherically symmetric morphology with an eosinophilic core, and containing α-syn and ubiquitin. Importantly, hMLOs generated from PD patient-derived inducible pluripotent stem cells (iPSCs) harboring SNCA triplication also exhibit subsequent degeneration of DA neurons and LBLI formation upon chronic GCase inhibitor treatment. Taken together, our hMLOs harbouring two major PD risk factors (GCase deficiency and overproduced α-syn) successfully recapitulate major pathophysiological signatures of the disease, and highlight the broad utility of brain organoid technology in modeling human neurodegenerative diseases.
2021-08-13 | E-MTAB-7302 | biostudies-arrayexpress
Project description:Kuznetsov2016(II) - α-syn aggregation
kinetics in Parkinson's
This theoretical model uses 2-step Finke-Watzky (FW) kinetics
todescribe the production, misfolding, aggregation, transport and
degradation of α-syn that may lead to Parkinson's Disease
(PD). Deregulated α-syn degradation is predicted to be
crucialfor PD pathogenesis.
This model is described in the article:
What can trigger the onset
of Parkinson's disease - A modeling study based on a
compartmental model of α-synuclein transport and aggregation in
neurons.
Kuznetsov IA, Kuznetsov AV.
Math Biosci 2016 Aug; 278: 22-29
Abstract:
The aim of this paper is to develop a minimal model
describing events leading to the onset of Parkinson's disease
(PD). The model accounts for α-synuclein (α-syn) production in
the soma, transport toward the synapse, misfolding, and
aggregation. The production and aggregation of polymeric α-syn
is simulated using a minimalistic 2-step Finke-Watzky model. We
utilized the developed model to analyze what changes in a
healthy neuron are likely to lead to the onset of α-syn
aggregation. We checked the effects of interruption of α-syn
transport toward the synapse, entry of misfolded (infectious)
α-syn into the somatic and synaptic compartments, increasing
the rate of α-syn synthesis in the soma, and failure of α-syn
degradation machinery. Our model suggests that failure of α-syn
degradation machinery is probably the most likely cause for the
onset of α-syn aggregation leading to PD.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000615.
To cite BioModels Database, please use:
BioModels Database:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
2024-09-02 | BIOMD0000000615 | BioModels
Project description:Alpha-synuclein (α-syn) aggregation and immune activation represent hallmark pathological events in Parkinson’s disease (PD). The PD-associated immune response encompasses both brain and peripheral immune cells, although little is known about the immune proteins relevant for such response. We propose that the upregulation of CD163 observed in blood monocytes and in the responsive microglia in the PD patients is a protective mechanism in the disease. To investigate this, we used the PD model based on intrastriatal injections of murine α-syn pre-formed fibrils (PFF) in CD163 knockout (KO) mice and wild-type littermates. CD163KO females revealed an impaired and differential early immune response to α-syn pathology as revealed by immunohistochemical and transcriptomic analysis. After 6 months, CD163KO females showed an exacerbated immune response and α-syn pathology, which ultimately led to a dopaminergic neurodegeneration of greater magnitude. These findings support a novel, sex-dimorphic neuroprotective role for CD163 during α-syn-induced neurodegeneration.
2023-12-14 | GSE243536 | GEO
Project description:Aggregated α-synuclein (α-SYN) proteins, encoded by the SNCA gene, are hallmarks of Lewy body disease (LBD), affecting multiple brain regions. However, the specific mechanisms underlying α-SYN pathology in cortical neurons, crucial for LBD-associated dementia, remain unclear. Here, we generated human cortical LBD models by differentiating induced pluripotent stem cells (iPSCs) from SNCA triplication LBD patients into cerebral organoids and observed increased levels of pathological α-SYN in these organoids. Single-cell RNA sequencing revealed prominent expression of the SNCA gene in excitatory neurons, which exhibited synaptic and mitochondrial dysfunction, consistent with findings in the cortex of LBD human brains. Furthermore, screening 1280 FDA-approved drugs identified four candidates, which inhibited α-SYN seeding in RT-QuIC assay, reduced α-SYN aggregation and alleviated mitochondrial dysfunction in SNCA triplication iPSC models. Our findings provide valuable insights into the development of cortical LBD models and the discovery of potential drugs targeting α-SYN aggregation.
2024-09-18 | GSE235914 | GEO
Project description:Parkinson’s disease (PD) is characterized by the accumulation of misfolded and aggregated alpha-synuclein (α-syn) into intraneuronal inclusions named Lewy bodies (LB). Although it is widely believed that α-syn plays a central role in the pathogenesis of PD, the processes that govern α-syn fibrillization and LB formation remain poorly understood. In this work, we sought to dissect the spatiotemporal events involved in the biogenesis of the LBs at the genetic, molecular, biochemical, structural, and cellular levels. Towards this goal, we further developed a seeding-based model of α-syn fibrillization to generate a neuronal model that reproduces all the key events leading to LB formation; including seeding, fibrillization, and the formation of inclusions that recapitulate many of the biochemical, structural, and organizational features of bona fide LBs. Using an integrative omics, biochemical and imaging approach, we dissected the molecular events associated with the different stages of LB formation and their contribution to neuronal dysfunction and degeneration. In addition, we demonstrate that LB formation involves a complex interplay between α-syn fibrillization, post-translational modifications, and interactions between α-syn aggregates and membranous organelles, including mitochondria, the autophagosome and endolysosome. Finally, we show that the process of LB formation, rather than simply fibril formation, is the major driver of neurodegeneration through disruption of cellular functions and inducing mitochondria damage and deficits, and synaptic dysfunctions. We believe that this model represents a powerful platform to further investigate the mechanisms of LB formation and clearance and to screen and evaluate novel therapeutics targeting α-syn aggregation and LB formation.
2020-01-15 | GSE142416 | GEO
Project description:Parkinson’s disease (PD) is characterized by the accumulation of misfolded and aggregated alpha-synuclein (α-syn) into intraneuronal inclusions named Lewy bodies (LB). Although it is widely believed that α-syn plays a central role in the pathogenesis of PD, the processes that govern α-syn fibrillization and LB formation remain poorly understood. In this work, we sought to dissect the spatiotemporal events involved in the biogenesis of the LBs at the genetic, molecular, biochemical, structural, and cellular levels. Towards this goal, we further developed a seeding-based model of α-syn fibrillization to generate a neuronal model that reproduces all the key events leading to LB formation; including seeding, fibrillization, and the formation of inclusions that recapitulate many of the biochemical, structural, and organizational features of bona fide LBs. Using an integrative omics, biochemical and imaging approach, we dissected the molecular events associated with the different stages of LB formation and their contribution to neuronal dysfunction and degeneration. In addition, we demonstrate that LB formation involves a complex interplay between α-syn fibrillization, post-translational modifications, and interactions between α-syn aggregates and membranous organelles, including mitochondria, the autophagosome and endolysosome. Finally, we show that the process of LB formation, rather than simply fibril formation, is the major driver of neurodegeneration through disruption of cellular functions and inducing mitochondria damage and deficits, and synaptic dysfunctions. We believe that this model represents a powerful platform to further investigate the mechanisms of LB formation and clearance and to screen and evaluate novel therapeutics targeting α-syn aggregation and LB formation.
2020-01-15 | PXD016850 | Pride
Project description:Background: Cell-to-cell propagation of α-synuclein (α-syn) aggregates is thought to contribute to the pathogenesis of Parkinson’s disease (PD) and underlie the spread of α-syn neuropathology. Increased pro-inflammatory cytokine levels and activated microglia are present in PD and activated microglia can promote α-syn aggregation. However, it is unclear how microglia influence α-syn cell-to-cell transfer. Methods: We developed a clinically relevant mouse model to monitor α-syn prion-like propagation between cells; we transplanted wild-type mouse embryonic midbrain neurons into a mouse striatum overexpressing human α-syn (huα-syn) following adeno-associated viral injection into the substantia nigra. In this system, we depleted or activated microglial cells and determined the effects on the transfer of huα-syn from host nigrostriatal neurons into the implanted dopaminergic neurons, using the presence of huα-syn within the grafted cells as a readout. Results: First, we compared α-syn cell-to-cell transfer between host mice with a normal number of microglia to mice in which we had pharmacologically ablated 80% of the microglia from the grafted striatum. With fewer host microglia, we observed increased accumulation of huα-syn in grafted dopaminergic neurons. Second, we assessed the transfer of α-syn into grafted neurons in the context of microglia activated by one of two stimuli, lipopolysaccharide (LPS) or interleukin-4 (IL-4). LPS exposure led to a strong activation of microglial cells (as determined by microglia morphology and cytokine production) and significantly higher amounts of huα-syn in grafted neurons. In contrast, injection of IL-4 did not change the proportion of grafted dopamine neurons that contained huα-syn relative to controls. RNA sequencing analysis revealed differential gene expression between LPS and IL-4 injected mice; many genes were upregulated in LPS including those involved with the inflammatory response. Conclusions: The absence or the hyperstimulation of microglia affected α-syn transfer in the brain. Our results suggest that under resting, non-inflammatory conditions, microglia modulate the transfer of α-syn. Pharmacological regulation of neuroinflammation could represent a future avenue for limiting the spread of PD neuropathology.
2019-08-12 | GSE130683 | GEO
Project description:A key process of neurodegeneration in Parkinson's disease (PD) is the transneuronal spreading of alpha-synuclein. Alpha-synuclein is a presynaptic protein that is implicated in the pathogenesis of PD and other synucleinopathies, where it forms, upon intracellular aggregation, pathological inclusions. Other hallmarks of PD include neurodegeneration and microgliosis in susceptible brain regions. Whether it is primarily transneuronal spreading of a-synuclein particles, inclusion formation, or other mechanisms, such as inflammation, that cause neurodegeneration in PD is unclear. We used spreading/aggregation of alpha-synuclein induced by intracerebral injection of a-synuclein preformed fibrils into the mouse brain to address this question. We performed quantitative histological analysis for a-synuclein inclusions, neurodegeneration, and microgliosis in different brain regions, and a gene expression profiling of the ventral midbrain, at two different timepoints after disease induction. We observed significant neurodegeneration and microgliosis in brain regions not only with, but also withouta-synuclein inclusions. We also observed prominent microgliosis in injured brain regions that did not correlate with neurodegeneration nor with inclusion load. In longitudinal gene expression profiling experiments, we observed early and unique alterations linked to microglial mediated inflammation that preceded neurodegeneration, indicating an active role of microglia in inducing neurodegeneration. Our observations indicate that a-synuclein inclusion formation is not the major driver in the early phases of PD-like neurodegeneration, but that diffusible, oligomeric a-synuclein species, which induce unusual microglial reactivity, play a key role in this process.
2020-11-02 | GSE155716 | GEO
Project description:Parkinson disease (PD) is closely linked to the misfolding and accumulation of α-synuclein (α-syn) into Lewy bodies. HTRA1 is a PDZ serine protease that degrades fibrillar tau, which is associated with Alzheimer disease (AD). Further, inactivating mutations to mitochondrial HTRA2 have been implicated in PD. Here, we establish that HTRA1 inhibits the aggregation of α-syn as well as FUS and TDP-43, which are implicated in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). We demonstrate that the protease domain of HTRA1 is necessary and sufficient for inhibition of aggregation, yet this activity is independent of HTRA1 proteolytic activity. Further, we find that HTRA1 also disaggregates preformed α-syn fibrils, which may promote their clearance. Treatment of α-syn fibrils with HTRA1 renders α-syn incapable of seeding the aggregation of endogenous α-syn in mammalian biosensor cells. We find that HTRA1 remodels α-syn by specifically targeting the NAC domain, which is the key domain that catalyzes α-syn oligomerization and fibrillization. Finally, in a primary neuron model of α-syn aggregation, we show that HTRA1 and its proteolytically inactive form both detoxify α-syn and prevent the formation of hyperphosphorylated α-syn accumulations. Our findings suggest that HTRA1 prevents aggregation and promotes disaggregation of multiple disease-associated proteins, and may be a therapeutic target for treating a range of neurodegenerative disorders.
2024-02-20 | PXD044806 | JPOST Repository