GPR34 senses demyelination to promote neuroinflammation and cognition impairment in Alzheimer's disease
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE216209 | GEO | 2025/02/05
REPOSITORIES: GEO
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Project description:Sterile neuroinflammation is a major driver of multiple neurological diseases. Myelin debris, which is released from the damaged myelin sheaths during demyelination, can act as an inflammatory stimulus to promote sterile inflammation and neurological pathologies, but the mechanism is poorly understood. Here, we show that lysophosphatidylserine (LysoPS)-GPR34 axis plays a critical role in microglia-mediated myelin debris sensing and the subsequent neuroinflammation. Myelin debris-induced microglia activation and proinflammatory cytokine expression relied on its lipid component LysoPS. Both myelin debris and LysoPS promoted microglia to produce IL-1and IL-6 via GPR34 and its downstream PI3K-AKT and ERK signaling. In vivo, LysoPS production and GPR34 signaling were found to be essential for neuroinflammation and pathologies in the mouse models of multiple sclerosis and stroke. Importantly, pharmacologic blockade of GPR34 showed potential therapeutic effects on these disease models. Thus, our results identify GPR34 as a key receptor to sense myelin debris and promote neuroinflammation, and suggest it as a potential target for demyelination-associated diseases.
2025-01-30 | GSE195741 | GEO
Project description:Neuroinflammation is one of the major neuropathological hallmarks of Alzheimer's disease (AD) and related tauopathies. Activated microglia often co-exist in the same brain regions where tau protein accumulates as hyperphosphorylated and aggregated PHFs or neurofibrillary tangles (NFTs) within neurons in patients with AD and related tauopathies. However, the exact mechanisms how pathological tau could induce neuroinflammatory responses are not clear. In this study, we treated primary human microglia with purified human PHFs and performed RNA-sequence analysis.
2021-09-16 | E-MTAB-5742 | biostudies-arrayexpress
Project description:Deposition of amyloid beta (Aβ) and hyperphosphorylated tau along with glial cell-mediated neuroinflammation are prominent pathogenic hallmarks of Alzheimer’s disease (AD). In recent years, impairment of autophagy has been found to be another important feature contributing to AD progression. Therefore, the potential of the autophagy activator spermidine, a small body-endogenous polyamine often used as dietary supplement, was assessed on Aβ pathology and glial cell-mediated neuroinflammation. Oral treatment of the amyloid prone AD-like APPPS1 mice with spermidine reduced neurotoxic soluble Aβ and decreased AD-associated neuroinflammation. A subsequent proteome analysis of isolated microglia confirmed the anti-inflammatory and revealed cytoskeletal effects of spermidine in APPPS1 mice. Our data highlight that the autophagy activator spermidine holds the potential to enhance Aβ degradation and to counteract microglia-mediated neuroinflammation in AD pathology.
2022-07-04 | PXD034638 | Pride
Project description:Deposition of amyloid beta (Aβ) and hyperphosphorylated tau along with glial cell-mediated neuroinflammation are prominent pathogenic hallmarks of Alzheimer’s disease (AD). In recent years, impairment of autophagy has been found to be another important feature contributing to AD progression. Therefore, the potential of the autophagy activator spermidine, a small body-endogenous polyamine often used as dietary supplement, was assessed on Aβ pathology and glial cell-mediated neuroinflammation. Oral treatment of the amyloid prone AD-like APPPS1 mice with spermidine reduced neurotoxic soluble Aβ and decreased AD-associated neuroinflammation during disease progression. Mechanistically, single nuclei sequencing revealed AD-associated microglia to be the main target of spermidine. This microglia population was characterized by increased AXL levels and expression of genes implicated in cell migration and phagocytosis. Our data highlight that the autophagy activator spermidine holds the potential to enhance Aβ degradation and to counteract glia-mediated neuroinflammation in AD pathology.
2022-07-04 | GSE206202 | GEO
Project description:GPR34 senses myelin debris to promote neuroinflammation and pathology
| PRJNA802043 | ENA
Project description:INTRODUCTION Alzheimer’s disease (AD) is an advanced neurodegenerative disorder characterized by progressive impairment in both memory loss and cognitive capacities, which resulting in severe dementia [1]. The pathogenesis of AD is complicated and poorly understood. According to the World Alzheimer Report 2018, it is estimated that AD affects at least 50 million persons throughout the world, and the number of people with AD will double nearly every 20 years [2]. Over the past decade, various theories have been developed for the neuropathological level of AD, but the most popular distinct pathological hallmarks is extracellular accumulation of amyloid beta (Aβ) plaques, as well as the neurofibrillary tangles (NFTs) composed of the hyperphosphorylated tau in the form of in the select brain regions [3]. The other factors including mitochondrial dysfunction, oxidative stress, brain inflammation and neurotransmitter disturbances pathology have been recognized as a contributing factor in the pathogenesis of AD [4]. To date, only symptomatic therapies are available for AD patients. Cholinesterase inhibitors (CIs) are approved for mild to moderate AD patients, and memantine is the only one N-methyl-D-aspartate receptor (NMDAR) antagonist has been approved for moderate to severe AD [5]. NMDAR is a glutamate ionotropic receptor, they display high Ca2+ permeability and voltage-dependent block by Mg2+[6]. In AD patients, NMDARs could be overactivated due to increasing glutamate release from presynaptic neurons. Overactived NMDARs lead first to Ca2+ overload in postsynaptic neurons, followed by desensitization and internalization, resulting in synaptic dysfunction and ultimately cell death [7, 8]. The numerous factors than can influence the levels of endogenous glutamate release in the pathogenesis of AD, deposition of Aβplaques, soluble Aβoligomers, NFTs, mitochondrial dysfunction and oxidative stress have been associated with the higher concentration of glutamate release[9, 10]. Memantine is an uncompetitive, moderate affinity NMDA receptor (NMDAR) antagonist which is used for a further therapeutic option of moderate to severe AD [5]. Its effects have been investigated in a large number of in vitro and in vivo studies, which indicated that memantine can against Aβ-induced glutamate-mediated toxicity, attenuate phosphorylation of tau and reduces level of total precursor protein (APP) in human neuroblastoma SK-N-SH cells [11], and lower Aβ1-42 secretion and plaques in primary cortical neuronal culture cells [9, 12]. Some studies showed that memantine also completely protected against Aβ-induced ROS injure in the primary hippocampal neurons [13]. Studies with transgenic animal models showed that memantine reduced the levels of soluble Aβ1-42, Aβ plaque deposition and lowered the loss of synaptic density in APP/PS1mice [4, 14, 15], and decreased the levels of total tau and hyperphosphorylated tau in 3×Tg-AD mice [3]. Furthermore, memantine altered genes expression in adult rat brain [16], and modulated protein profiles in Down syndrome mice brain [17]. However, no comprehensive study of proteomic characteristics description of 3×Tg-AD transgenic mice under the memantine treatment has been conducted to date as far as we searched. In order to better understand the multiple actions of memantine, we conducted detailed analysis of proteomics and bioinformatics to dissect the molecular mechanisms of memantine for the treatment of AD.
2019-11-12 | PXD012110 | Pride
Project description:Alzheimer’s Disease (AD) is characterized by the deposition of protein aggregates such as neurofibrillary tangles (NFTs) and amyloid (Aβ) plaques in the brain. Post-translational modification through ubiquitylationplays critical roles in clearing misfolded protein aggregates. Investigating global ubiquitylation changes inAD brain may provide insights regarding the underlying mechanisms of proteostasis and disease pathogenesis.Here, we utilizedan immunoaffinity approach to specifically enrichubiquitinated(di-glycine) peptides frompostmortemhuman control and AD braintissues.Mass spectrometry(MS)based proteomicanalysis identified global ubiquitylation changes associated with ADand hierarchical clustering of the human brain ubiquitylome clearly classified AD cases from healthy controls based on ubiquitylation patterns. Polyubiquitin linkage analysis identified increased levels of all seven polyubiquitin linkage typesas well as total ubiquitin in the AD brain tissues.We also report novel ubiquitylation sites in the microtubulebinding repeatof Tauwith potential implicationsfor Tauaggregation. Dually modified peptides with both phosphorylation and ubiquitylationsites, many of which originated from Tauprotein are also differentially enriched in AD.Furthermore, all the KXGS motifswithin themicrotubule binding region (MTBR)of Tauprotein,which represents the core ofNFTs,are enriched among dually modified peptides. Collectively, these studieshighlight the utility of an immunoaffinity enrichment approach coupled with MSanalysis for mapping AD associated global ubiquitylome changesas well as to gain insights intounderlying proteostasis pathwaysaltered in AD brain.
2019-06-25 | PXD009199 | Pride
Project description:Accumulation of damaged mitochondria is a hallmark of human aging and age-related neurodegenerative pathologies, including Alzheimer’s disease (AD). However, the molecular mechanisms of the impaired mitochondrial homeostasis and their relationship to AD are still elusive. Here we provide evidence that mitophagy, a cellular process mediating selective clearance of dysfunctional mitochondria, is impaired in AD patient hippocampus, in iPSC-derived human neurons and in animal AD models. In C. elegans models of AD, pharmacological stimulation of mitophagy reverses memory impairment through a PINK-1, PDR-1 and DCT-1 dependent pathway. Mitophagy induction diminishes the levels of insoluble amyloid-β (Aβ)1-42 and Aβ1-40 peptide isoforms and prevents cognitive impairment in AD mice by a mechanism involving microglial phagocytosis of extracellular Aβ plaques and suppression of neuroinflammation. Furthermore, mitophagy abolishes AD-related Tau hyperphosphorylation in human neuronal cells and reverses memory impairment in transgenic Tau nematodes. Our findings suggest that impaired removal of defective mitochondria is a pivotal event in AD pathogenesis. Interventions that stimulate mitophagy therefore have therapeutic potential in the prevention and treatment of AD.
2018-11-26 | GSE111737 | GEO
Project description:One of the hallmarks of Alzheimer’s disease is the presence of extracellular diffuse and fibrillar plaques predominantly consisting of the amyloid-β (Aβ) peptide. ApoE influences the deposition of amyloid pathology through affecting the clearance and aggregation of monomeric Aβ in the brain. In addition to influencing Aβ metabolism, increasing evidence suggests that apoE influences microglial function in neurodegenerative diseases. Here, we characterize the impact that apoE has on amyloid pathology and the innate immune response in APPPS1∆E9 and APPPS1-21 transgenic mice. We report that Apoe deficiency reduced fibrillar plaque deposition consistent with previous studies. However, fibrillar plaques in Apoe-deficient mice exhibited a striking reduction in plaque compaction. Hyperspectral fluorescent imaging using luminescent conjugated oligothiophenes identified distinct Aβ morphotypes in Apoe-deficient mice. We also observed a significant reduction in fibrillar plaque-associated microgliosis and activated microglial gene expression in Apoe-deficient mice, along with significant increases in dystrophic neurites around fibrillar plaques. Our results suggest that apoE is critical in stimulating the innate immune response to amyloid pathology.
2018-02-15 | GSE109906 | GEO
Project description:Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that is pathologically characterized by amyloid β-peptide (Aβ)-containing plaques and the generation of neurofibrillary tangles (NFTs). Although proteome profile changes have been reported in AD brains, it is unclear whether they represent a continuous process from mild to severe changes or whether there is a sequence, with step-by-step involvement of proteins. To address this we analyzed neocortex samples of 19 control cases without signs of neurodegeneration (nonAD), 17 pathologically-diagnosed preclinical AD (p-preAD), and 17 symptomatic AD cases by mass spectrometry after homogenization and separation into soluble, dispersible, membrane-associated, and plaque-associated fractions. Here, we show three classes of proteins exhibiting changed levels during the pathogenesis and progression of AD from the AD pathology-free to the symptomatic stage: five early- and 24 late-responding proteins and 17 gradually changing proteins. The identified proteins and hierarchy point to endocytosis/synaptic vesicle cycle-related processes as key elements in the initiation of AD pathology in the neocortex, while later changes document the resulting neurodegenerative process.
2021-06-21 | PXD020020 | Pride