Cyclic GMP-AMP synthase (cGAS) deletion promotes less prominent inflammatory macrophages and sepsis severity in catheter-induced infection mice
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PROVIDER: PRJNA1200068 | ENA |
REPOSITORIES: ENA
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Project description:Activation of cGAS, a cytosolic DNA receptor, in macrophages might be important in sepsis (a life-threatening condition caused by infection). The severity of sepsis induced by subcutaneous implantation of Pseudomonas-contaminated catheter in cGAS-deficient (cGAS-/-) mice was less severe than in wild-type (WT) as indicated by liver enzymes, total white blood cell count, cytokines, and M1-polarized macrophages in the spleens (flow cytometry analysis), but not bacteremia, endotoxemia, and serum cell-free DNA. Patterns of the transcriptome of lipopolysaccharide (LPS)-stimulated bone marrow-derived mac-rophages were clearly different between cGAS-/- and WT cells. Gene set enrichment analysis (GSEA) indicated more prominent enrichment of oxidative phosphorylation (OXPHOS) and mTORC1 pathways in LPS-activated cGAS-/- macrophages compared with WT. Meanwhile, LPS upregulated cGAS and increased cGAMP (a cGAS inducer) only in WT macrophages along with less severe inflammation in cGAS-/- macrophages, as in-dicated by supernatant cytokines, pro-inflammatory molecules (NF-κB), M1 polarization (IL-1β, CD80, and CD86), and macrophage-extracellular traps (METs) through detection of citrullinated histone 3 (CitH3) in supernatant and in immunofluorescent visualization. In conclusion, less severe inflammatory responses of cGAS-/- macrophages than WT were demonstrated in mice (catheter-induced sepsis) and in vitro (transcriptomic analysis, macrophage polarization, and METs). Further studies using cGAS inhibitors in bacterial sepsis are interesting.
2025-03-22 | GSE284706 | GEO
Project description:Here we report that activation of cyclic GMP-AMP synthase (cGAS) diminishes cognitive resilience by decreasing the neuronal transcriptional network of myocyte enhancer factor 2c (MEF2C) through type I interferon (IFN-I) signaling. Pathogenic tau activates cGAS and IFN-I responses in microglia, in part mediated by cytosolic leakage of mitochondrial DNA. Genetic ablation of cGAS in tauopathy mice diminished microglial IFN-I response, preserved synapse integrity and plasticity, and protected against cognitive impairment without affecting the pathogenic tau load. cGAS ablation enhanced, while activation of IFN-I downregulated, neuronal MEF2C expression network linked with cognitive resilience in AD.
2023-04-26 | GSE226381 | GEO
Project description:The cyclic dinucleotides 3'-5'diadenylate (c-diAMP) and 3'-5' diguanylate (c-diGMP) are important bacterial second messengers that have recently been shown to stimulate the secretion of type I Interferons (IFN-Is) through the c-diGMP-binding protein MPYS/STING. Here, we show that physiologically relevant levels of cyclic dinucleotides also stimulate a robust secretion of IL-1β through the NLRP3 inflammasome. Intriguingly, this response is independent of MPYS/STING. Consistent with most NLRP3 inflammasome activators, the response to c-diGMP is dependent on the mobilization of potassium and calcium ions. However, in contrast to other NLRP3 inflammasome activators, this response is not associated with significant changes in mitochondrial potential or the generation of mitochondrial reactive oxygen species. Thus, cyclic dinucleotides activate the NLRP3 inflammasome through a unique pathway that could have evolved to detect pervasive bacterial pathogen-associated molecular patterns associated with intracellular infections.
| S-EPMC3807221 | biostudies-literature
Project description:Vibrio cholerae is a facultative human pathogen. The ability of V. cholerae to form biofilms is crucial for its survival in aquatic habitats between epidemics and is advantageous for host-to-host transmission during epidemics. Formation of mature biofilms requires the production of extracellular matrix components, including Vibrio polysaccharide (VPS) and matrix proteins. Biofilm formation is positively controlled by the transcriptional regulators VpsR and VpsT and is negatively regulated by the quorum-sensing transcriptional regulator HapR, as well as the cyclic AMP (cAMP)-cAMP receptor protein (CRP) regulatory complex. Transcriptome analysis of cyaA (encoding adenylate cyclase) and crp (encoding cAMP receptor protein) deletion mutants revealed that cAMP-CRP negatively regulates transcription of both VPS biosynthesis genes and genes encoding biofilm matrix proteins. Further mutational and expression analysis revealed that cAMP-CRP negatively regulates transcription of vps genes indirectly through its action on vpsR transcription. However, negative regulation of the genes encoding biofilm matrix proteins by cAMP-CRP can also occur independent of VpsR. Transcriptome analysis also revealed that cAMP-CRP regulates the expression of a set of genes encoding diguanylate cyclases (DGCs) and phosphodiesterases. Mutational and phenotypic analysis of the differentially regulated DGCs revealed that a DGC, CdgA, is responsible for the increase in biofilm formation in the Deltacrp mutant, showing the connection between of cyclic di-GMP and cAMP signaling in V. cholerae.
| S-EPMC2566190 | biostudies-literature
Project description:Cyclic GMP-AMP synthase and interferon activation diminish MEF2C-mediated cognitive resilience
| PRJNA940101 | ENA
Project description:Cyclic di-AMP is an essential second messenger in many Gram-positive bacteria, including the model organism Bacillus subtilis. Here, we analyzed the transcriptome of a strain accumulating c-di-AMP in vivo. Our results demonstrate that accumulation of c-di-AMP affects the expression of several hundred genes, among them many mother-cell specific sporulation genes. Additionally, the two major biofilm operons, epsA-O and tapA-sipW-tasA, are affected. High levels of c-di-AMP abolish transcription of genes responsible for biofilm formation which in turn leads to a defect in complex colony formation in B. subtilis.
2016-05-25 | GSE79716 | GEO
Project description:The recently discovered mammalian enzyme cyclic GMP-AMP synthase produces cyclic GMP-AMP (cGAMP) after being activated by pathogen-derived cytosolic double stranded DNA. The product can stimulate STING-dependent interferon type I signaling. Here, we explore the efficacy of cGAMP as a mucosal adjuvant in mice. We show that cGAMP can enhance the adaptive immune response to the model antigen ovalbumin. It promotes antigen specific IgG and a balanced Th1/Th2 lymphocyte response in immunized mice. A characteristic of the cGAMP-induced immune response is the slightly reduced induction of interleukin-17 as a hallmark of Th17 activity--a distinct feature that is not observed with other cyclic di-nucleotide adjuvants. We further characterize the innate immune stimulation activity in vitro on murine bone marrow-derived dendritic cells and human dendritic cells. The observed results suggest the consideration of cGAMP as a candidate mucosal adjuvant for human vaccines.
| S-EPMC4190368 | biostudies-literature
Project description:Mammalian cyclic GMP-AMP synthase (cGAS) and its homologue dinucleotide cyclase in Vibrio cholerae (VcDncV) produce cyclic dinucleotides (CDNs) that participate in the defense against viral infection. Recently, scores of new cGAS/DncV-like nucleotidyltransferases (CD-NTases) were discovered, which produce various CDNs and cyclic trinucleotides (CTNs) as second messengers. Here, we present the crystal structures of EcCdnD, a CD-NTase from Enterobacter cloacae that produces cyclic AMP-AMP-GMP, in its apo-form and in complex with ATP, ADP and AMPcPP, an ATP analogue. Despite the similar overall architecture, the protein shows significant structural variations from other CD-NTases. Adjacent to the donor substrate, another nucleotide is bound to the acceptor binding site by a non-productive mode. Isothermal titration calorimetry results also suggest the presence of two ATP binding sites. GTP alone does not bind to EcCdnD, which however binds to pppApG, a possible intermediate. The enzyme is active on ATP or a mixture of ATP and GTP, and the best metal cofactor is Mg2+. The conserved residues Asp69 and Asp71 are essential for catalysis, as indicated by the loss of activity in the mutants. Based on structural analysis and comparison with VcDncV and RNA polymerase, a tentative catalytic pathway for the CTN-producing EcCdnD is proposed.
| S-EPMC8096243 | biostudies-literature
Project description:Cyclic dinucleotides are an important class of signaling molecules that regulate a wide variety of pathogenic responses in bacteria, but tools for monitoring their regulation in vivo are lacking. We have designed RNA-based fluorescent biosensors for cyclic di-GMP and cyclic AMP-GMP by fusing the Spinach aptamer to variants of a natural GEMM-I riboswitch. In live cell imaging experiments, these biosensors demonstrate fluorescence turn-on in response to cyclic dinucleotides, and they were used to confirm in vivo production of cyclic AMP-GMP by the enzyme DncV.
| S-EPMC3775879 | biostudies-literature
Project description:Cyclic GMP-AMP synthase and interferon activation diminish MEF2C-mediated cognitive resilience II
| PRJNA940108 | ENA