Apolipoprotein E regulates lipid metabolism and α-synuclein pathology in human iPSC-derived cerebral organoids.
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ABSTRACT:
SUBMITTER: Zhao J
PROVIDER: S-EPMC8500881 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Parkinson's disease (PD) is the second most common neurodegenerative disorder and a central role for α-synuclein (αSyn; SNCA) in disease aetiology has been proposed based on genetics and neuropathology. To better understand the pathological mechanisms of αSyn, we generated induced pluripotent stem cells (iPSCs) from healthy individuals and PD patients carrying the A53T SNCA mutation or a triplication of the SNCA locus and differentiated them into dopaminergic neurons (DAns). iPSC-derived DAn from PD patients carrying either mutation showed increased intracellular αSyn accumulation, and DAns from patients carrying the SNCA triplication displayed oligomeric αSyn pathology and elevated αSyn extracellular release. Transcriptomic analysis of purified DAns revealed perturbations in expression of genes linked to mitochondrial function, consistent with observed reduction in mitochondrial respiration, impairment in mitochondrial membrane potential, aberrant mitochondrial morphology and decreased levels of phosphorylated DRP1Ser616. Parkinson's iPSC-derived DAns showed increased endoplasmic reticulum stress and impairments in cholesterol and lipid homeostasis. Together, these data show a correlation between αSyn cellular pathology and deficits in metabolic and cellular bioenergetics in the pathology of PD.
| S-EPMC6548224 | biostudies-literature
Project description:MHCII molecules, expressed by professional antigen-presenting cells (APCs) such as T cells and B cells, are hypothesized to play a key role in the response of cellular immunity to α-synuclein (α-syn). However, the role of cellular immunity in the neuroanatomic transmission of α-syn pre-formed fibrillar (PFF) seeds is undetermined. To illuminate whether cellular immunity influences the transmission of α-syn seeds from the periphery into the CNS, we injected preformed α-syn PFFs in the hindlimb of the Line M83 transgenic mouse model of synucleinopathy lacking MhcII. We showed that a complete deficiency in MhcII accelerated the appearance of seeded α-syn pathology and shortened the lifespan of the PFF-seeded M83 mice. To characterize whether B-cell and T-cell inherent MhcII function underlies this accelerated response to PFF seeding, we next injected α-syn PFFs in Rag1-/- mice which completely lacked these mature lymphocytes. There was no alteration in the lifespan or burden of endstage α-syn pathology in the PFF-seeded, Rag1-deficient M83+/- mice. Together, these results suggested that MhcII function on immune cells other than these classical APCs is potentially involved in the propagation of α-syn in this model of experimental synucleinopathy. We focused on microglia next, finding that while microglial burden was significantly upregulated in PFF-seeded, MhcII-deficient mice relative to controls, the microglial activation marker Cd68 was reduced in these mice, suggesting that these microglia were not responsive. Additional analysis of the CNS showed the early appearance of the neurotoxic astrocyte A1 signature and the induction of the Ifnγ-inducible anti-viral response mediated by MhcI in the MhcII-deficient, PFF-seeded mice. Overall, our data suggest that the loss of MhcII function leads to a dysfunctional response in non-classical APCs and that this response could potentially play a role in determining PFF-induced pathology. Collectively, our results identify the critical role of MhcII function in synucleinopathies induced by α-syn prion seeds.
| S-EPMC9332117 | biostudies-literature
Project description:To examine the pathogenic role of α-synuclein (αS) in Parkinson's Disease, we have generated induced Pluripotent Stem Cell lines from early onset Parkinson's Disease patients with SNCA A53T and SNCA Triplication mutations, and in this study have differentiated them to PSC-macrophages (pMac), which recapitulate many features of their brain-resident cousins, microglia. We show that SNCA Triplication pMac, but not A53T pMac, have significantly increased intracellular αS versus controls and release significantly more αS to the medium. SNCA Triplication pMac, but not A53T pMac, show significantly reduced phagocytosis capability and this can be phenocopied by adding monomeric αS to the cell culture medium of control pMac. Fibrillar αS is taken up by pMac by actin-rearrangement-dependent pathways, and monomeric αS by actin-independent pathways. Finally, pMac degrade αS and this can be arrested by blocking lysosomal and proteasomal pathways. Together, these results show that macrophages are capable of clearing αS, but that high levels of exogenous or endogenous αS compromise this ability, likely a vicious cycle scenario faced by microglia in Parkinson's disease.
| S-EPMC5567139 | biostudies-literature
Project description:Starting two decades ago with the discoveries of genetic links between alpha-synuclein and Parkinson's disease risk and the identification of aggregated alpha-synuclein as the main protein constituent of Lewy pathology, alpha-synuclein has emerged as the major therapeutic target in Parkinson's disease and related synucleinopathies. Following the suggestion that alpha-synuclein pathology gradually spreads through the nervous system following a stereotypic pattern and the discovery that aggregated forms of alpha-synuclein can propagate pathology from one cell to another, and thereby probably aggravate existing deficits as well as generate additional symptoms, the idea that alpha-synuclein is a viable therapeutic target gained further support. In this review we describe current challenges and possibilities with alpha-synuclein as a therapeutic target. We briefly highlight gaps in the knowledge of the role of alpha-synuclein in disease, and propose that a deeper understanding of the pathobiology of alpha-synuclein can lead to improved therapeutic strategies. We describe several treatment approaches that are currently being tested in advanced animal experiments or already are in clinical trials. We have divided them into approaches that reduce alpha-synuclein production; inhibit alpha-synuclein aggregation inside cells; promote its degradation either inside or outside cells; and reduce its uptake by neighbouring cells following release from already affected neurons. Finally, we briefly discuss challenges related to the clinical testing of alpha-synuclein therapies, for example difficulties in monitoring target engagement and the need for relatively large trials of long duration. We conclude that alpha-synuclein remains one of the most compelling therapeutic targets for Parkinson's disease, and related synucleinopathies, and that the multitude of approaches being tested provides hope for the future.
| S-EPMC6541231 | biostudies-literature
Project description:We report the single-cell RNA sequencing of day 33±2 human iPSC derived cerebral organoids harboring a CRIPSR/CAS9 mediated, heterozygous knock-out of the gene EML1 or the respective isogenic control organoids. By microdissection of several ventricular zones per organoid from 3 different batches followed by dissociation into single cells we obtained transcriptomic data of several thousand cells and we were able to identify different cell populations including RG cells (RG1), RG cells transitioning to bRG cells (RG to bRG), RG cells transitioning to neurons (RG2), intermediate progenitors and young neurons based on known marker genes (Nowakowski et al., 2017; Fan et al., 2020; Velasco et al., 2019; Pollen et al., 2015; Liu et al., 2017). When comparing the cell type composition between EML1-heKO and isogenic control-derived organoids we found a clear decrease of RG1 cells and a striking increase in the abundance of RG to bRG cells in the EML1-heKO condition, while only minor variations in the other cell clusters were observed. We further investigated molecular characteristics of the EML1-heKO derived RG to bRG cluster compared to control. Here we found a set of differentially expressed genes in the EML1-heKO compared to control. When further investigating these genes, we identified a clear upregulation of ECM and bRG markers Our data suggest that the RG to bRG cell cluster in the EML1-heKO is composed of a rather perturbed progenitor population not found as such in control organoids and most likely not reflecting a cell population present during normal human brain development.
2022-01-31 | GSE195666 | GEO
Project description:Backgroundα-Synuclein (αS) is the major component of several types of brain inclusions including Lewy bodies, a hallmark of Parkinson's disease. Aberrant aggregation of αS also is associated with cellular demise in multiple neurologic disorders collectively referred to as synucleinopathies. Recent studies demonstrate the induction of αS pathology by a single intracerebral injection of exogenous amyloidogenic αS in adult non-transgenic and transgenic mice expressing human αS. To further investigate the mechanism of pathology induction and evaluate an experimental paradigm with potential for higher throughput, we performed similar studies in neonatal mice injected with αS.ResultsIn non-transgenic mice, we observed limited induction of neuronal αS inclusions predominantly 8 months after brain injection of aggregated, amyloidogenic human αS. More robust inclusion pathology was induced in transgenic mice expressing wild-type human αS (line M20), and inclusion pathology was observed at earlier time points. Injection of a non-amyloidogenic (Δ71-82) deletion protein of αS was also able to induce similar pathology in a subset of M20 transgenic mice. M20 transgenic mice injected with amyloidogenic or non-amyloidogenic αS demonstrated a delayed and robust induction of brain neuroinflammation that occurs in mice with or without αS pathological inclusions implicating this mechanism in aggregate formation.ConclusionsThe finding that a non-amyloidogenic Δ71-82 αS can induce pathology calls into question the simple interpretation that exogenous αS catalyzes aggregation and spread of intracellular αS pathology solely through a nucleation dependent conformational templating mechanism. These results indicate that several mechanisms may act synergistically or independently to promote the spread of αS pathology.
| S-EPMC3893388 | biostudies-literature
Project description:Parkinson's Disease (PD) is a common neurodegenerative disorder affecting millions of people worldwide for which there are only symptomatic therapies. Small molecules able to target key pathological processes in PD have emerged as interesting options for modifying disease progression. We have previously shown that a (poly)phenol-enriched fraction (PEF) of Corema album L. leaf extract modulates central events in PD pathogenesis, namely α-synuclein (αSyn) toxicity, aggregation and clearance. PEF was now subjected to a bio-guided fractionation with the aim of identifying the critical bioactive compound. We identified genipin, an iridoid, which relieves αSyn toxicity and aggregation. Furthermore, genipin promotes metabolic alterations and modulates lipid storage and endocytosis. Importantly, genipin was able to prevent the motor deficits caused by the overexpression of αSyn in a Drosophila melanogaster model of PD. These findings widens the possibility for the exploitation of genipin for PD therapeutics.
| S-EPMC10079842 | biostudies-literature
Project description:The typical abnormalities observed in the brain of Alzheimer's disease (AD) patients include synaptic alterations, neuronal death, brain inflammation, and the accumulation of protein aggregates in the form of amyloid plaques and neurofibrillary tangles. Despite the development of many animal and in vitro models for AD, there is a lack of an experimental approach that fully recapitulates essential aspects of the disease in human cells. Here, we report the generation of a new model to study AD, consisting of cerebral organoids (COs) produced from human-induced pluripotent stem cells (iPSCs). Under our experimental conditions, COs grow to form three-dimensional (3D) structures containing neural areas with cortical-like organization. Analysis of COs by histological and biochemical methods revealed that organoids produced from iPSCs derived from patients affected by familial AD or Down syndrome (DS) spontaneously develop over time pathological features of AD, including accumulation of structures highly reminiscent to amyloid plaques and neurofibrillary tangles. These pathological abnormalities were not observed in COs generated from various controls, including human iPSCs from healthy individuals, human iPSCs from patients affected by Creutzfeldt-Jakob disease, mouse embryonic stem cells (ESCs), or mouse iPSCs. These findings enable modeling genetic AD in a human cellular context in a 3D cortical-like tissue developed in vitro from patient-specific stem cells. This system provides a more relevant disease model compared to pre-existing methods and offers a new platform for discovery of novel targets and screening of drugs for therapeutic intervention.
| S-EPMC6594704 | biostudies-literature
Project description:In Lewy body disease (LBD) such as dementia with LBs and Parkinson's disease, several lines of evidence show that disrupted proteolysis occurs. p62/SQSTM1 (p62) is highly involved with intracellular proteolysis and is a component of ubiquitin-positive inclusions in various neurodegenerative disorders. However, it is not clear whether p62 deficiency affects inclusion formation and abnormal protein accumulation. To answer this question, we used a mouse model of LBD that lacks p62, and found that LB-like inclusions were observed in transgenic mice that overexpressed α-synuclein (Tg mice) with or without the p62 protein. p62 deficiency enhanced α-synuclein pathology with regard to the number of inclusions and staining intensity compared with Tg mice that expressed p62. To further investigate the molecular mechanisms associated with the loss of p62 in Tg mice, we assessed the mRNA and protein levels of several molecules, and found that the neighbor of the brca1 gene (NBr1), which is functionally and structurally similar to p62, is increased in Tg mice without p62 compared with control Tg mice. These findings suggest that p62 and NBR1 affect the pathogenesis of neurodegenerative diseases through the cooperative modulation of α-synuclein aggregation.
| S-EPMC8029467 | biostudies-literature
Project description:Malformations of human cortical development (MCD) can cause severe disabilities. The lack of human-specific models hampers our understanding of the molecular underpinnings of the intricate processes leading to MCD. Here, we use cerebral organoids derived from patients and genome edited induced pluripotent stem cells to address pathophysiological changes associated with a complex MCD caused by mutations in the Echinoderm microtubule-associated protein-like 1 (EML1) gene. EML1-deficient organoids display ectopic neural rosettes at the basal side of the ventricular zone areas and clusters of heterotopic neurons. Single-cell RNA sequencing shows an upregulation of basal radial glial (RG) markers and human-specific extracellular matrix components in the ectopic cell population. Gene ontology and molecular analyses suggest that ectopic progenitor cells originate from perturbed apical RG cell behavior and yes-associated protein 1 (YAP1) triggered expansion. Our data highlight a progenitor origin of EML1-mutation induced MCD and provide new mechanistic insight into the human disease pathology.
| S-SCDT-EMBOR-2021-54027-T | biostudies-other