Microglial response to Aβ and prostaglandin-E2 EP4 receptor activation
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE55627 | GEO | 2014/04/25
SECONDARY ACCESSION(S): PRJNA240243
REPOSITORIES: GEO
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Project description:A persistent and non-resolving inflammatory response to accumulating A? peptide species is a cardinal feature in the development of Alzheimer's disease (AD). In response to accumulating A? peptide species, microglia, the innate immune cells of the brain, generate a toxic inflammatory response that accelerates synaptic and neuronal injury. Many pro-inflammatory signaling pathways are linked to progression of neurodegeneration. However, endogenous anti-inflammatory pathways capable of suppressing A?-induced inflammation represent a relatively unexplored area. Here we hypothesized that signaling through the prostaglandin-E2 (PGE2) EP4 receptor potently suppresses microglial inflammatory responses to A?42 peptides. In cultured microglial cells, EP4 stimulation attenuated levels of A?42-induced inflammatory factors and potentiated phagocytosis of A?42. Microarray analysis was performed and demonstrated that EP4 stimulation broadly opposed A?42-driven gene expression changes in microglia, with enrichment for targets of IRF1, IRF7, and NF-?B transcription factors. Primary microglia were isolated from the brains of postnatal day 7 C57BL/6J mouse pups using the Neural Tissue Dissociation Kit (P), MACS Separation Columns (LS), and magnetic CD11b Microbeads from Miltenyi Biotec (Auburn, CA). Microglia from three separate litters of pups were maintained as three independent biological replicates for each treatment. After being cultured for three days, microglia were treated with oligomeric A?42 (10uM) and/or the specific EP4 agonist AE1-329 (100nM) for 6 hours. These 4 treatment conditions (A? + AE1, A? alone, AE1 alone, and vehicle alone) and 3 independent biological replicates per treatment gave us 12 total samples. After 6 hours of treatment, RNA was isolated from the microglia for microarray analysis.
2014-04-25 | E-GEOD-55627 | biostudies-arrayexpress
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2018-09-18 | PXD009137 | Pride
Project description:Dysregulation of microglial function contributes to Alzheimer’s disease (AD) pathogenesis. Several genetic and transcriptome studies have revealed microglia specific genetic risk factors, and changes in microglia expression profiles in AD pathogenesis, viz. the human-Alzheimer’s microglia/myeloid (HAM) profile in AD patients and the disease-associated microglia profile (DAM) in AD mouse models. The transcriptional changes involve genes in immune and inflammatory pathways, and in pathways associated with Aβ clearance. Aβ oligomers have been suggested to be the initial trigger of microglia activation in AD. To study the direct response to Aβ oligomers exposure, we assessed changes in gene expression in an in vitro model for microglia, the human monocyte-derived microglial-like (MDMi) cells. We confirmed the initiation of an inflammatory profile following LPS stimulation, based on increased expression of IL1B, IL6, and TNFα. In contrast, the Ab1-42 oligomers did not induce an inflammatory profile or a classical HAM or DAM profile. Interestingly, we observed a specific increase in the expression of metallothioneins in the Aβ1-42 oligomer treated MDMi cells. Metallothioneins are involved in metal ion regulation, protection against reactive oxygen species, and have anti-inflammatory properties. In conclusion, our data suggests that Aβ1-42 oligomers may trigger a protective response both in vitro and in vivo.
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2023-07-18 | GSE208006 | GEO
Project description:Microglia, the innate immune cells of the central nervous system, perform critical inflammatory and non-inflammatory functions to maintain homeostasis and normal neural function. However in Alzheimer’s disease (AD), these beneficial functions become progressively impaired, contributing to synapse and neuron loss and cognitive impairment. The inflammatory cyclooxygenase-PGE2 pathway, including the PGE2 receptor EP2, is implicated in AD development, both in human epidemiology and in transgenic models of AD. To test the transcriptional responses of EP2-deficient microglia to Aβ in vivo, we used mice in which the EP2 receptor is conditionally deleted in microglia using the CD11b-Cre transgene and floxed alleles of the EP2 gene. By injecting these mice with Aβ ICV and isolating microglia from the brains, we have been able to establish the transcriptional response of microglia to Aβ in vivo and test how EP2 deletion in microglia affects this response. 8 month-old C57BL/6 mice, of the genotype CD11b-Cre; EP2+/+ or CD11b-Cre; EP2lox/lox, were injected I.C.V. with either Aβ or vehicle. 48 hours after injection, the mice were sacrificed and transcardially perfused with cold heparinized 0.9% NaCl. Brains were then removed from the mice and pooled, two brains of the same genotype per sample, to ensure adequate cell and RNA yield. The brains were then enzymatically dissociated for microglia isolation using the Neural Tissue Dissociation Kit (P), MACS Separation Columns (LS), and magnetic CD11b Microbeads from Miltenyi Biotec according to the manufacturer's protocol. Immediately after isolating the microglia, RNA was extracted from the cells for microarray analysis.
2015-02-20 | E-GEOD-57181 | biostudies-arrayexpress
Project description:Impairment of microglial clearance activity contributes to beta-amyloid (Aβ) pathology in Alzheimer disease (AD). While the transcriptome profile of microglia directs microglial functions, how the microglial transcriptome can be regulated to alleviate AD pathology is largely unknown. Here, we show that injection of interleukin (IL)-33 in an AD transgenic mouse model ameliorates Aβ pathology by reprogramming microglial epigenetic and transcriptomic profiles to induce a microglial subpopulation with enhanced phagocytic activity. These IL-33–responsive microglia (IL-33RM) express distinct transcriptome signature, highlighted by major histocompatibility complex class II genes, and restored homeostatic signature genes. IL-33–induced remodeling of chromatin accessibility and PU.1 transcription factor binding at the signature genes of IL-33RM control their transcriptome reprogramming. Specifically, disrupting PU.1–DNA interaction abolishes the microglial state transition and Aβ clearance induced by IL-33. Thus, we define a PU.1-dependent transcriptional pathway that drives the IL-33–induced functional state transition of microglia, resulting in enhanced Aβ clearance.
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Project description:Microglial response to Aβ and prostaglandin-E2 EP4 receptor activation
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Project description:INTRODUCTION: Gain-of-function mutations in INPP5D, which encodes for the SH2-domain-containing inositol phosphatase SHIP-1, have recently been linked to an increased risk of developing late-onset Alzheimer’s disease (LOAD). Yet, little is currently known in regards to how SHIP-1 affects neurobiology or neurodegenerative disease pathogenesis. METHODS: To bridge this knowledge gap, we generated 5xFAD Inpp5dfl/flCx3cr1Ert2Cre mice to investigate the function of microglial SHIP-1 signaling in response to amyloid beta (Aβ)-mediated pathology. RESULTS: In our studies, we found that SHIP-1 deletion in microglia leads to substantially enhanced recruitment of microglia to Aβ plaques, altered microglial gene expression, and marked improvements in neuronal health. Further, SHIP-1 loss enhanced microglial plaque containment and Aβ engulfment when compared to microglia from Cre-negative 5xFAD Inpp5dfl/fl littermate controls. DISCUSSION: These results define SHIP-1 as a pivotal regulator of microglial responses during Aβ-driven neurological disease.
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