Genome-wide analysis of LPS-responsive gene expression by microglia cells in Ntg and LRRK2KO mouse brain
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE83562 | GEO | 2016/06/22
SECONDARY ACCESSION(S): PRJNA326349
REPOSITORIES: GEO
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Project description:Analysis of LRRK2-regulation of microglia responce to the LPS at gene expression level. The hypothesis tested in the present study was whether LRRK2 influence the microglial phagocytosis- and neuroinflammation- related gene expression at mRNA level. Total RNA obtained from microglia cells isolated from Ntg or LRRK2KO mouse brain subjected to 6 or 24 hours of LPS treatment in vitro
2016-06-22 | E-GEOD-83562 | biostudies-arrayexpress
Project description:We used the RNA-Sequencing to obtain transcriptomic profiles of LRRK2 wild-type (WT) and knock-out (KO) microglia cells treated with α-synuclein pre-formed fibrils (PFFs) or lipopolysaccharide (LPS) as a general inflammatory insult. Conclusion: overall, the results suggest that microglial LRRK2 may contribute to the pathogenesis of PD via altered oxidative stress signaling.
2021-10-26 | GSE186483 | GEO
Project description:Mutations in leucine-rich repeat kinase 2 (LRRK2) cause autosomal dominant Parkinson’s disease (PD) while polymorphic LRRK2 variants are associated with sporadic PD. PD-linked mutations increase LRRK2 kinase activity and induce neurotoxicity in vitro and in vivo. The small GTPase Rab8a is a LRRK2 kinase substrate and is involved in receptor-mediated recycling and endocytic trafficking of transferrin, but the effect of PD-linked LRRK2 mutations on the function of Rab8a is poorly understood. Here, we show that gain-of-function mutations in LRRK2 induce sequestration of endogenous Rab8a to lysosomes in over-expression cell models while pharmacological inhibition of LRRK2 kinase activity reverses this phenotype. Furthermore, we show that LRRK2 mutations drive association of endocytosed transferrin with Rab8a-positive lysosomes. LRRK2 has been nominated as an integral part of cellular responses downstream of proinflammatory signals and is activated in microglia in post-mortem PD tissue. Here, we show that iPSC-derived microglia from patients carrying the most common LRRK2 mutation, G2019S, mistraffic transferrin to lysosomes proximal to the nucleus in proinflammatory conditions. Furthermore, G2019S knock-in mice show a significant increase in iron deposition in microglia following intrastriatal LPS injection compared to wild type mice, accompanied by striatal accumulation of ferritin. Conclusion: Our data support a role of LRRK2 in modulating iron uptake and storage in response to proinflammatory stimuli in microglia. Neuroinflammation remodels endolysosomal gene expression in microglia, in vitro and in vivo.
2021-10-29 | GSE186559 | GEO
Project description:BACKGROUND: Previous data implicates neuroinflammation in the pathogenesis of Parkinson’s disease (PD). Of the genes associated with PD, Leucine rich repeat kinase 2 (LRRK2) is expressed in microglia, resident brain inflammatory cells. However, the extent to which LRRK2 affects neuroinflammatory responses is unclear. OBJECTIVE: To examine whether mutations in Lrrk2 affect responses to neuroinflammation in vivo. METHODS: We injected cohorts of mice carrying mutations in Lrrk2, homologous to those causing human PD, with a single intrastriatal injection of lipopolysaccharide (LPS) or control. We used single cell RNA-Sequencing to examine cell type specific responses to treatment and genotype and validated key results with orthogonal approaches. RESULTS: We found that our chosen paradigm of acute LPS exposure evokes robust transcriptional changes consistent with a multicellular neuroinflammatory response. We also found evidence of peripheral immune cell recruitment into the brain and interaction with brain-resident microglia. However, the transcriptional effects of Lrrk2 mutations were limited to small numbers of genes, including down regulation of gene ontogeny terms related to lysosomes, predominantly in microglia. CONCLUSIONS: Our data clearly demonstrate that many cells in the brain respond to a single inflammatory insult with strong transcriptional responses and that, even in a model focussed on CNS injection, there is interaction between peripheral and central immune cells. In contrast, the quantitative effects of Lrrk2 mutations are modest at least at the level of transcription, demonstrating that additional studies are needed to clarify whether Lrrk2 affects neuroinflammation in an endogenous context.
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Project description:Neuroinflammation is thought to contribute to the pathogenesis of Alzheimer’s disease (AD), yet numerous studies have demonstrated a beneficial role for neuroinflammation in amyloid plaque clearance. We have previously shown that sustained expression of IL-1β in the hippocampus of APP/PS1 mice decreases amyloid plaque burden independent of recruited CCR2+ myeloid cells, suggesting resident microglia as the main phagocytic effectors of IL-1β-induced plaque clearance. To date, however, the mechanisms of IL-1β-induced plaque clearance remain poorly understood. To determine whether IL-1β-induced plaque clearance is due to enhanced microglial phagocytosis of Aβ, APP/PS1 mice induced to express mature human IL-1β in the hippocampus via adenoviral transduction were treated with the Aβ fluorescent probe methoxy-X04 (MX04) and microglial internalization of Aβ was analyzed by flow cytometry and immunohistochemistry. We found that resident microglia (CD45loCD11b+) constituted >70% of the MX04+ cells in both control and IL-1β-treated conditions, and that <10% of MX04+ cells were recruited myeloid cells (CD45hiCD11b+). However, we found that IL-1β treatment did not augment the percentage of MX04+ microglia nor the quantity of Aβ internalized by individual microglia. Instead, we found that IL-1β treatment resulted in a significant increase in the total number of MX04+ microglia in the hippocampus due to IL-1β-induced proliferation. Consistent with these results, transcriptomic analyses revealed very similar gene expression profiles between MX04+ and MX04- microglia, indicating IL-1β does not drive enhanced expression of phagocytosis-related genes. By contrast, IL-1β treatment was associated with large-scale changes in the expression of genes related to proliferation, immune function and inflammation. Together, these studies demonstrate that IL-1β induces microglial proliferation and the expression of genes involved in inflammatory immune functions that may be related to Aβ clearance.
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Project description:Sequencing data related to the manuscript entitled, "CD22 blockade restores homeostatic microglial phagocytosis in the aging brain."
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Project description:The most common genetic mutation found in familial and sporadic amyotrophic lateral sclerosis (ALS), as well as fronto-temporal dementia (FTD), is a repeat expansion in the C9orf72 gene. C9orf72 is highly expressed in human myeloid cells, and although neuroinflammation and microglial pathology are widely found in ALS/FTD, the underlying mechanisms are poorly understood. Here, using human induced pluripotent stem cell-derived microglia-like cells (hiPSC-MG) harbouring C9orf72 mutation (mC9-MG) together with gene-corrected isogenic controls (isoC9-MG) and C9ORF72 knock-out hiPSC-MG (C9KO-MG), we show that reduced C9ORF72 protein is associated with impaired phagocytosis and an exaggerated inflammatory response upon stimulation with lipopolysaccharide, driven by sustained activation of NLRP3 inflammasome and NF-kB signalling. Analysis of the hiPSC-MG C9ORF72 interactome revealed an association of C9ORF72 with key regulators of autophagy, a process involved in the homeostatic regulation of the innate immune response. We found impaired initiation of autophagy in C9KO-MG and mC9-MG. Furthermore, through motor neuron-microglial (MN-MG) co-culture studies, we identified that autophagy deficit in mC9-MG led to increased vulnerability of C9 MNs to excitotoxic stimulus. Pharmacological activation of autophagy ameliorated the sustained activation of NLRP3 inflammasome and NF-B signalling, reversed the phagocytic deficit found in mC9-MG and also reduced MN death in MN-MG co-cultures. We validated these findings in blood-derived macrophages from people with C9orf72 mutation. Our results reveal an important role for C9ORF72 in regulating microglial immune homeostasis and identify dysregulation in human myeloid cells as a contributor to neurodegeneration in ALS/FTD
2023-03-02 | PXD032320 | Pride
Project description:Sequencing data related to the manuscript entitled, "CD22 blockade restores homeostatic microglial phagocytosis in the aging brain."
2019-03-01 | GSE127543 | GEO
Project description:The role of microglia cells in Alzheimer’s disease (AD) is well recognized, however their molecular and functional diversity remain unclear. Here we isolated amyloid plaque-containing (using labelling with methoxy–XO4, XO4+) and non-containing (XO4-) microglia from an AD mouse model. Transcriptomics analysis identified different transcriptional trajectories in ageing and AD mice. XO4+ microglial transcriptomes demonstrated dysregulated expression of genes associated with late onset AD. We further showed that the transcriptional program associated with XO4+ microglia from mice is present in a subset of human microglia isolated from brains of individuals with AD. XO4- microglia displayed transcriptional signatures associated with accelerated ageing and contained more intracellular post-synaptic material than XO4+ microglia, despite reduced active synaptosome phagocytosis. We identified HIF1α as potentially regulating synaptosome phagocytosis in vitro using primary human microglia, and BV2 mouse microglial cells. Together these findings provide insight into molecular mechanisms underpinning the functional diversity of microglia in AD.
2021-04-12 | PXD024731 | Pride
Project description:Niemann-Pick type C (NPC) disease is a rare neurodegenerative disorder mainly caused by autosomal recessive mutations in Npc1 which result in abnormal late endosomal/lysosomal lipid storage. Although microgliosis is one of the prominent pathological features, consequences of NPC1 loss on microglial function and disease outcome remain largely unknown. Here, we provide an in-depth characterization of microglial proteomic signatures and phenotypes in an NPC1-deficient (Npc1-/-) murine model. We demonstrate that microglial defects, including enhanced phagocytosis and impaired lipid trafficking, occur early in the NPC pathological cascade and precede neuronal death. Compromised microglial function during Npc1-/- mouse development is reflected by enhanced synaptic pruning and deficient turnover of myelin. Accumulation of the undigested myelin occurs mainly within multi-vesicular bodies (MVBs) of Npc1-/- microglia and not within lysosomes. This is in agreement with the impairments in recycling of myelin into lipid droplets. Macrophages of NPC patients displayed similar molecular and functional alterations as murine Npc1-/- microglia, strengthening the role of NPC1 in immune homeostasis. Generated ex vivo assays using patient macrophages are novel promising clinical tools to monitor the progression and therapeutic efficacy in NPC patients.
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