Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA131929 | ENA |
REPOSITORIES: ENA
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Project description:Microglia are the resident mononuclear phagocytes of the CNS parenchyma and represent an initial line of defense against invading microorganisms. Microglia utilize Toll-like receptors (TLRs) for pathogen recognition and TLR2 specifically senses conserved motifs of gram-positive bacteria including lipoproteins, lipoteichoic acids, and peptidoglycan (PGN) leading to cytokine/chemokine production. Interestingly, primary microglia derived from TLR2 knockout (KO) mice over-expressed numerous IL-12 family members, including IL-12p40, IL-12p70, and IL-27 in response to intact S. aureus, but not the less structurally complex TLR2 ligands Pam3CSK4 or PGN. The ability of intact bacteria to augment IL-12 family member expression was specific for gram-positive organisms, since numerous gram-negative strains were unable to elicit exaggerated responses in TLR2 KO microglia. Inhibition of SYK or IRAK4 signaling did not impact heightened IL-12 family member production in S. aureus-treated TLR2 KO microglia, whereas PI3K, MAPK, and JNK inhibitors were all capable of restoring exaggerated cytokine expression to wild type levels. Additionally, elevated IL-12 production in TLR2 KO microglia was ablated by a TLR9 antagonist, suggesting that TLR9 drives IL-12 family member production following exposure to intact bacteria that remains unchecked in the absence of TLR2 signaling. Collectively, these findings indicate crosstalk between TLR2 and TLR9 pathways to regulate IL-12 family member production by microglia. The summation of TLR signals must be tightly controlled to ensure the timely cessation and/or fine tuning of cytokine signaling to avoid nonspecific bystander damage due to sustained IL-12 release.
2014-12-22 | GSE24935 | GEO
Project description:Microglia are the resident mononuclear phagocytes of the CNS parenchyma and represent an initial line of defense against invading microorganisms. Microglia utilize Toll-like receptors (TLRs) for pathogen recognition and TLR2 specifically senses conserved motifs of gram-positive bacteria including lipoproteins, lipoteichoic acids, and peptidoglycan (PGN) leading to cytokine/chemokine production. Interestingly, primary microglia derived from TLR2 knockout (KO) mice over-expressed numerous IL-12 family members, including IL-12p40, IL-12p70, and IL-27 in response to intact S. aureus, but not the less structurally complex TLR2 ligands Pam3CSK4 or PGN. The ability of intact bacteria to augment IL-12 family member expression was specific for gram-positive organisms, since numerous gram-negative strains were unable to elicit exaggerated responses in TLR2 KO microglia. Inhibition of SYK or IRAK4 signaling did not impact heightened IL-12 family member production in S. aureus-treated TLR2 KO microglia, whereas PI3K, MAPK, and JNK inhibitors were all capable of restoring exaggerated cytokine expression to wild type levels. Additionally, elevated IL-12 production in TLR2 KO microglia was ablated by a TLR9 antagonist, suggesting that TLR9 drives IL-12 family member production following exposure to intact bacteria that remains unchecked in the absence of TLR2 signaling. Collectively, these findings indicate crosstalk between TLR2 and TLR9 pathways to regulate IL-12 family member production by microglia. The summation of TLR signals must be tightly controlled to ensure the timely cessation and/or fine tuning of cytokine signaling to avoid nonspecific bystander damage due to sustained IL-12 release. TLR2 KO mice were backcrossed with C57BL/6 animals for a minimum of eight generations prior to use in these studies. Age- and sex-matched C57BL/6 mice were used as wild type (WT) controls. Primary mixed glial cultures were prepared from the cerebral corticies of neonatal mice (2-4 days of age) and microglia were harvested using a differential shaking technique with a purity of >98%. A USA300 community-acquired methicillin-resistant S. aureus (CA-MRSA) clinical isolate recovered from a patient with a fatal brain abscess was used to stimulate the microglia isolates. Bacterial strains were heat-inactivated and used to stimulate microglia at 107 colony forming units (cfu)/well for 6 and 12 hours time points. Three replicates of each mouse type (WT, TLR2 KO) at both time points 6 and 12 hours were used for the microarray experiments. Data was only usable for 2 replicates of the KO-12 hr group.
2014-12-22 | E-GEOD-24935 | biostudies-arrayexpress
Project description:To investigate the similarity of toll-like receptor tolerance in macrophages stimulated with different toll-like receptor ligands we stimulated naïve or tolerant macrophages with ligands for TLR4, TLR2, TLR3 and TLR9. The data identifies a core set of genes that are tolerised by all ligands and genes that show TLR specific patterns.
2018-05-30 | GSE81291 | GEO
Project description:Interferon-induced transmembrane protein 3 (IFITM3) is a restriction factor that limits viral pathogenesis and exerts poorly understood immunoregulatory functions. Here, using human and mouse models, we demonstrate that IFITM3 promotes MyD88-dependent, TLR-mediated IL-6 production following exposure to cytomegalovirus (CMV). IFITM3 also restricts IL-6 production in response to influenza and SARS-CoV-2. In dendritic cells, IFITM3 binds to the reticulon 4 isoform Nogo-B and promotes its proteasomal degradation. We reveal that Nogo-B mediates TLR-dependent pro-inflammatory cytokine production and promotes viral pathogenesis in vivo, and in the case of TLR2 responses, this process involves alteration of TLR2 cellular localization. Nogo-B deletion abrogates inflammatory cytokine responses and associated disease in virus-infected IFITM3-deficient mice. Thus, we uncover Nogo-B as a driver of viral pathogenesis and highlight an immunoregulatory pathway in which IFITM3 fine-tunes the responsiveness of myeloid cells to viral stimulation.
2022-07-28 | PXD035254 | Pride
Project description:Mesenchymal stem cells are often transplanted in inflammatory environments and they are able to survive and modulate host immune responses through mechanism poorly understood. In this paper we analyzed biological responses of MSC in response IL-1M-NM-2 as a representative inflammatory mediator. Microarray analysis of MSC treated with IL-1M-NM-2 revealed that this cytokine activates a set of biological process related with cell survival, cell migration, cell adhesion, chemokine production, induction of angiogenesis and modulation of immune response. Further analysis by real-time PCR and functional assays revealed that IL-1M-NM-2 mainly increases production of chemokines CCL5, CCL20, CXCL1, CXCL3, CXCL5, CXCL6, CXCL10, CXCL11 and CX3CL1, interleukins IL-6, IL-8, IL23A, IL32, Toll-like receptors TLR2, TLR4, CLDN1, metalloproteins MMP1 and MMP3, growth factors CSF2 and TNF, together with adhesion molecules ICAM1 and ICAM4. Functional analysis of MSC proliferation, migration and adhesion to extracellular matrix components revealed that IL-1M-NM-2 did not affect proliferation whereas constitute a throphic factor for MSC and increases adhesion mainly to collagen and laminin. Moreover, IL-1M-NM-2 treatment enhanced the ability of MSC to recruit monocytes and granulocytes cells in vitro. Blockade of NFkM-NM-2 transcription factor activation with IM-NM-:B kinase beta (IKKb) siRNA impaired MSC migration, adhesion and leucocyte recruitment, indicating that NF-kB signaling pathway is the main mechanism implicated in these biological processes. These findings are relevant for designing protocols that implicate MSC delivery into inflammatory environments. Comparison between two experimental conditions, one sample for each condition
2012-06-21 | E-GEOD-33755 | biostudies-arrayexpress
Project description:Abnormal accumulation of aggregated proteins and sustained microglial activation are important contributors of neurodegenerative process in neurological diseases. Recent studies have shown that aggregation-prone proteins, such as a-synuclein, the protein implicated in Parkinson’s disease (PD), are released from neuronal cells and thus present in the extracellular fluid, pointing to the possible paracrine effects of these proteins on microglial immune responses. However, the mechanism underlying the disease-associated microglial activation and the role of neuronal proteins in this process remain unknown. Here, we show that extracellular a-synuclein released from neuronal cells is an endogenous ligand of toll-like receptor 2 (TLR2) and activates microglia, which in turn induces neurodegeneration. Interaction between neuron-released a-synuclein and TLR2 and subsequent activation of the TLR2 signaling were demonstrated comprehensively by using computational modeling of signaling network and by the experimental validation in TLR2-deficient microglia both in vitro and in vivo. In contrast to the neuron-released a-synuclein, recombinant a-synuclein proteins, including monomer, oligomer, fibril, or nitrated forms, were not able to interact or activate TLR2, suggesting that neuronal cells have a mechanism of enriching specific forms of a-synuclein capable of activating TLR2 during the process of releasing this protein. Taken together, the results suggest that both neuron-released extracellular a-synuclein and TLR2 might be novel therapeutic targets for modifying neuroinflammation in PD and related neurodegenerative diseases. We collected culture media from differentiated SH-SY5Y cells overexpressing either human a-synuclein (alpha-SCM) or beta-galactosidase (LZCM) and treat these media to primary rat microglia at the concentration of a-synuclein of 1.1M. Transcriptome analyses with microglial cells treated with either aSCM or LZCM at two different time points, 6 h and 24 h.
2013-02-28 | E-GEOD-26532 | biostudies-arrayexpress
Project description:The cell death protease caspase-8 plays an essential role in controlling inflammation, as severe immunodeficiency results from its loss. We previously found that caspase-8 promotes inflammatory responses by cleaving NEDD4-binding protein 1 (N4BP1), a suppressor of cytokine production, but the underlying mechanisms remained unclear. Here we find that N4BP1 curtails the duration, rather than initial induction, of proinflammatory signaling through a mechanism involving noncanonical IKK (ncIKK)-mediated inhibition of the canonical IkB kinase (IKK) complex, a crosstalk event among the IKK family facilitated by N4BP1. Accordingly, co-deletion of the ncIKKs or their adaptor protein TANK largely phenocopied deletion of N4BP1, augmenting cytokine responses by macrophages upon engagement of TRIF-independent toll-like receptors (TLR) 1/2, TLR7, or TLR9. Like N4BP1, TANK was largely prevented from inhibiting the TRIF-dependent TLR4 response due to caspase-8. Biochemically, N4BP1 binds both the canonical and noncanonical IKK complexes, in a manner promoted by linear and/or K63-linked polyubiquitin chain binding by N4BP1 and independent of its RNAse activity. Consistent with this, a knock-in mutant of N4BP1 with diminished ubiquitin chain-binding capacity led to increased proinflammatory cytokine responses. These findings thereby unveil a mechanism of late-phase inflammatory gene control, whereby N4BP1 prevents persistent IKK activity through ncIKK-mediated inhibition. This molecular crosstalk among caspase-8, N4BP1, and the IKKs and ncIKKs may have implications for our understanding of genetic immune diseases caused by mutations in caspase-8 or TBK1 and suggest a novel ‘guarding’ mechanism against pathogens that attempt to subvert the ncIKKs.
2024-04-01 | GSE219005 | GEO
Project description:The cell death protease caspase-8 plays an essential role in controlling inflammation, as severe immunodeficiency results from its loss. We previously found that caspase-8 promotes inflammatory responses by cleaving NEDD4-binding protein 1 (N4BP1), a suppressor of cytokine production, but the underlying mechanisms remained unclear. Here we find that N4BP1 curtails the duration, rather than initial induction, of proinflammatory signaling through a mechanism involving noncanonical IKK (ncIKK)-mediated inhibition of the canonical IkB kinase (IKK) complex, a crosstalk event among the IKK family facilitated by N4BP1. Accordingly, co-deletion of the ncIKKs or their adaptor protein TANK largely phenocopied deletion of N4BP1, augmenting cytokine responses by macrophages upon engagement of TRIF-independent toll-like receptors (TLR) 1/2, TLR7, or TLR9. Like N4BP1, TANK was largely prevented from inhibiting the TRIF-dependent TLR4 response due to caspase-8. Biochemically, N4BP1 binds both the canonical and noncanonical IKK complexes, in a manner promoted by linear and/or K63-linked polyubiquitin chain binding by N4BP1 and independent of its RNAse activity. Consistent with this, a knock-in mutant of N4BP1 with diminished ubiquitin chain-binding capacity led to increased proinflammatory cytokine responses. These findings thereby unveil a mechanism of late-phase inflammatory gene control, whereby N4BP1 prevents persistent IKK activity through ncIKK-mediated inhibition. This molecular crosstalk among caspase-8, N4BP1, and the IKKs and ncIKKs may have implications for our understanding of genetic immune diseases caused by mutations in caspase-8 or TBK1 and suggest a novel ‘guarding’ mechanism against pathogens that attempt to subvert the ncIKKs.
2024-04-01 | GSE218957 | GEO
Project description:The cell death protease caspase-8 plays an essential role in controlling inflammation, as severe immunodeficiency results from its loss. We previously found that caspase-8 promotes inflammatory responses by cleaving NEDD4-binding protein 1 (N4BP1), a suppressor of cytokine production, but the underlying mechanisms remained unclear. Here we find that N4BP1 curtails the duration, rather than initial induction, of proinflammatory signaling through a mechanism involving noncanonical IKK (ncIKK)-mediated inhibition of the canonical IkB kinase (IKK) complex, a crosstalk event among the IKK family facilitated by N4BP1. Accordingly, co-deletion of the ncIKKs or their adaptor protein TANK largely phenocopied deletion of N4BP1, augmenting cytokine responses by macrophages upon engagement of TRIF-independent toll-like receptors (TLR) 1/2, TLR7, or TLR9. Like N4BP1, TANK was largely prevented from inhibiting the TRIF-dependent TLR4 response due to caspase-8. Biochemically, N4BP1 binds both the canonical and noncanonical IKK complexes, in a manner promoted by linear and/or K63-linked polyubiquitin chain binding by N4BP1 and independent of its RNAse activity. Consistent with this, a knock-in mutant of N4BP1 with diminished ubiquitin chain-binding capacity led to increased proinflammatory cytokine responses. These findings thereby unveil a mechanism of late-phase inflammatory gene control, whereby N4BP1 prevents persistent IKK activity through ncIKK-mediated inhibition. This molecular crosstalk among caspase-8, N4BP1, and the IKKs and ncIKKs may have implications for our understanding of genetic immune diseases caused by mutations in caspase-8 or TBK1 and suggest a novel ‘guarding’ mechanism against pathogens that attempt to subvert the ncIKKs.
2024-04-01 | GSE218956 | GEO
Project description:The cell death protease caspase-8 plays an essential role in controlling inflammation, as severe immunodeficiency results from its loss. We previously found that caspase-8 promotes inflammatory responses by cleaving NEDD4-binding protein 1 (N4BP1), a suppressor of cytokine production, but the underlying mechanisms remained unclear. Here we find that N4BP1 curtails the duration, rather than initial induction, of proinflammatory signaling through a mechanism involving noncanonical IKK (ncIKK)-mediated inhibition of the canonical IkB kinase (IKK) complex, a crosstalk event among the IKK family facilitated by N4BP1. Accordingly, co-deletion of the ncIKKs or their adaptor protein TANK largely phenocopied deletion of N4BP1, augmenting cytokine responses by macrophages upon engagement of TRIF-independent toll-like receptors (TLR) 1/2, TLR7, or TLR9. Like N4BP1, TANK was largely prevented from inhibiting the TRIF-dependent TLR4 response due to caspase-8. Biochemically, N4BP1 binds both the canonical and noncanonical IKK complexes, in a manner promoted by linear and/or K63-linked polyubiquitin chain binding by N4BP1 and independent of its RNAse activity. Consistent with this, a knock-in mutant of N4BP1 with diminished ubiquitin chain-binding capacity led to increased proinflammatory cytokine responses. These findings thereby unveil a mechanism of late-phase inflammatory gene control, whereby N4BP1 prevents persistent IKK activity through ncIKK-mediated inhibition. This molecular crosstalk among caspase-8, N4BP1, and the IKKs and ncIKKs may have implications for our understanding of genetic immune diseases caused by mutations in caspase-8 or TBK1 and suggest a novel ‘guarding’ mechanism against pathogens that attempt to subvert the ncIKKs.
2024-04-01 | GSE218955 | GEO