STING mediates immune responses in a unicellular choanoflagellate
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ABSTRACT:
ORGANISM(S): Monosiga brevicollis
PROVIDER: GSE174340 | GEO | 2021/05/13
REPOSITORIES: GEO
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Project description:DNA sensing is a fundamental process in the immune system, including host defence against viruses. The DNA sensor cGAS synthesises 2’3’ cyclic GMP-AMP (cGAMP), a second messenger that activates STING, which subsequently induces innate immunity. cGAMP not only activates STING in the cell where it is produced but also transfers to other cells. Transporters, channels and pores including SLC19A1, the SLC46A family, P2X7, ABCC1 and volume-regulated anion channels (VRACs) release cGAMP into the extracellular space and/or import cGAMP into cells. Emerging evidence suggests these proteins are important in antiviral immunity. Here, we investigated whether viruses antagonise cGAMP transporters, channels and pores. We report that infection with multiple human viruses depleted cGAMP conduits from cells. This included herpes simplex virus 1 (HSV-1) that targeted the VRAC subunits LRRC8A and LRRC8C, as well as SLC46A2 and P2X7, for degradation. The HSV-1 protein UL56 was required and sufficient for these effects that were mediated at least partially by proteasomal turnover. UL56 thereby inhibited the cGAMP uptake via VRAC, SLC46A2 and P2X7. Taken together, we show that HSV-1 actively antagonises cGAMP transfer across the plasma membrane and propose this limits innate immunity by reducing cell-to-cell communication via the immunotransmitter cGAMP.
2024-04-15 | PXD043229 | Pride
Project description:The volume-regulated anion channel (VRAC) is a hexameric complex formed by LRRC8 proteins. VRACs are responsible for the regulatory volume decrease (RVD) after hypotonic cell swelling by mediating the efflux of chloride. Besides chloride, LRRC8 proteins transport other molecules including immunomodulatory cyclic dinucleotides (CDNs) such as 2’3’cGAMP. Here we identify LRRC8C as a critical component of VRACs in T cells, where its deletion abolishes VRAC currents and RVD. We find that LRRC8C mediates the transport of 2’3’cGAMP in T cells. T cells of Lrrc8c-/- mice have increased cell cycle progression, proliferation, survival, Ca2+ influx and cytokine production in vitro and enhanced T cell mediated immunity in vivo. We used RNA sequencing of CD4+ T cells from wild-type (WT) and Lrrc8c-/- mice to determine the effects of impaired cGAMP signaling in T cells. T cells of Lrrc8c-/- mice had impaired p53 signaling which was associated with decreased p53 expression. We found that uptake of 2’3’cGAMP and other CDNs via LRRC8C results in STING activation and p53 accumulation. Inhibition of STING in WT T cells recapitulates the phenotype of LRRC8C-deficient T cells whereas overexpression of p53 inhibits enhanced T cell function in the absence of LRRC8C. These findings establish cGAMP uptake through LRRC8C and subsequent STING-p53 signaling as a novel inhibitory signaling pathway in T cells and adaptive immunity.
2021-12-31 | GSE163679 | GEO
Project description:The accumulation of DNA in the cytosol serves as a key immunostimulatory signal associated with infections, cancer and genomic damage. Cytosolic DNA triggers immune responses by activating the cGAS/STING pathway. The binding of DNA to the cytosolic enzyme cGAMP synthase (cGAS), activates its enzymatic activity, leading to the synthesis of a second messenger, cyclic[G(2’,5’)pA(3’,5’)] (2’3’-cGAMP). 2’3’-cGAMP, a cyclic dinucleotide (CDN), activates the protein ‘stimulator of interferon genes’ (STING), which in turn activates the transcription factors IRF3 and NF-κB promoting the transcription of genes encoding type I interferons and other cytokines and mediators that stimulate a broader immune response. Exogenous 2’3’-cGAMP produced by malignant cells and other CDNs, including CDNs produced by bacteria and synthetic CDNs used in cancer immunotherapy, must traverse the cell membrane to activate STING in target cells. How these charged CDNs pass through the lipid bilayer is unknown. Here we used a genome-wide CRISPR interference screen to identify the reduced folate carrier SLC19A1, a folate-organic phosphate antiporter, as the major transporter for CDNs. CDN uptake and functional responses are inhibited by depleting SLC19A1 from human cells and enhanced by overexpressing SLC19A1. In both human cell lines and primary cells ex vivo, CDN uptake is inhibited by folates, as well as two medications approved for treatment of inflammatory diseases, sulfasalazine and the antifolate methotrexate. The identification of SLC19A1 as the major transporter of CDNs into cells has implications for the immunotherapeutic treatment of cancer, host responsiveness to CDN-producing pathogenic microorganisms, and potentially in certain inflammatory diseases.
2019-09-01 | GSE134371 | GEO
Project description:Activation of the STING (Stimulator of Interferon Genes) pathway by microbial or self-DNA, as well as cyclic di nucleotides (CDN), results in the induction of numerous genes that suppress pathogen replication and facilitate adaptive immunity. However, sustained gene transcription is rigidly prevented to avoid lethal STING-dependent pro-inflammatory disease by mechanisms that remain unknown. We demonstrate here that after autophagy-dependent STING delivery of TBK1 (TANK-binding kinase 1) to endosomal/lysosomal compartments and activation of transcription factors IRF3 (interferon regulatory factors 3) and NF-κB (nuclear factor kappa beta), that STING is subsequently phosphorylated by serine/threonine UNC-51-like kinase (ULK1/ATG1) and IRF3 function is suppressed. ULK1 activation occurred following disassociation from its repressor adenine monophosphate activated protein kinase (AMPK), and was elicited by CDN’S generated by the cGAMP synthase, cGAS. Thus, while CDN’s may initially facilitate STING function, they subsequently trigger negative-feedback control of STING activity, thus preventing the persistent transcription of innate immune genes. Total RNA obtained from primary STING deficient mouse embryonic fibroblast reconstituted with mSTING (W), S365A variant (A), or S365D variant (D). These cells were transfected with dsDNA (ISD) for 3 hours.
2013-10-10 | E-GEOD-51199 | biostudies-arrayexpress
Project description:We recently reported that an orthologue of STING regulates infection by picorna-like viruses in drosophila. Here, we show that injection of flies with 2’3’-cGAMP can induce expression of dSTING-regulated genes. Analysis of the transcriptome of 2’3’-cGAMP injected flies reveals a complex pattern of response, with early and late induced genes. Our results reveal that dSTING regulates an NF-κB -dependent antiviral program, which predates the emergence of Interferon Regulatory Factors and interferons in vertebrates.
2020-05-31 | GSE140955 | GEO
Project description:In mammals, the cGAS-cGAMP-STING pathway is crucial for sensing viral infection and initiating an anti-viral type I interferon response. cGAS and STING are highly conserved genes that originated in bacteria and are present in most animals. By contrast, interferons only emerged in vertebrates; thus, the function of STING in invertebrates is unclear. Here, we use the STING ligand 2'3'-cGAMP to activate immune responses in a model cnidarian invertebrate, the starlet sea anemone Nematostella vectensis. Using RNA-Seq, we found that 2'3'-cGAMP induces robust transcription of both anti-viral and anti-bacterial genes, including the conserved transcription factor NF-κB. Knockdown experiments identified a role for NF-κB in specifically inducing anti-bacterial genes downstream of 2'3'-cGAMP, and some of these genes were also found to be induced during Pseudomonas aeruginosa infection. Furthermore, we characterized the protein product of one of the putative anti-bacterial genes, the N. vectensis homolog of Dae4, and found that it has conserved anti-bacterial activity. This work describes an unexpected role of a cGAMP sensing pathway in anti-bacterial immunity and suggests that a broad transcriptional response is an evolutionarily ancestral output of 2'3'-cGAMP signaling in animals.
2021-06-03 | GSE175984 | GEO
Project description:The cytosolic DNA sensor cyclic GMP-AMP (cGAMP) synthetase (cGAS) has emerged as a fundamental component fueling the anti-pathogen immunity. Because of its pivotal role in initiating innate immune response, the activity of cGAS must be tightly fine-tuned to maintain immune homeostasis in antiviral response. Here, we reported that neddylation modification was indispensable for appropriate cGAS-STING signaling activation. Blocking neddylation pathway using neddylation inhibitor MLN4924 substantially impaired the induction of type I interferon and proinflammatory cytokines, which was selectively dependent on Nedd8 E2 enzyme Ube2m. We further found that deficiency of the Nedd8 E3 ligase Rnf111 greatly attenuated DNA-triggered cGAS activation while not affecting cGAMP induced activation of STING, demonstrating that Rnf111 was the Nedd8 E3 ligase of cGAS. We further identified Lys231 and Lys421 as the key neddylation sites in human cGAS. Mechanistically, Rnf111 interacted with and polyneddylated cGAS, which in turn promoted its dimerization and enhanced the DNA-binding ability, leading to proper cGAS-STING pathway activation. In the same line, the Ube2m or Rnf111 deficiency mice exhibited severe defects in innate immune response and were susceptible to HSV-1 infection. Collectively, our study uncovered a vital role of the Ube2m-Rnf111 neddylation axis in promoting the activity of the cGAS-STING pathway and highlighted the importance of neddylation modification in antiviral defense.
2021-02-22 | PXD024088 | Pride
Project description:Activation of the STING (Stimulator of Interferon Genes) pathway by microbial or self-DNA, as well as cyclic di nucleotides (CDN), results in the induction of numerous genes that suppress pathogen replication and facilitate adaptive immunity. However, sustained gene transcription is rigidly prevented to avoid lethal STING-dependent pro-inflammatory disease by mechanisms that remain unknown. We demonstrate here that after autophagy-dependent STING delivery of TBK1 (TANK-binding kinase 1) to endosomal/lysosomal compartments and activation of transcription factors IRF3 (interferon regulatory factors 3) and NF-κB (nuclear factor kappa beta), that STING is subsequently phosphorylated by serine/threonine UNC-51-like kinase (ULK1/ATG1) and IRF3 function is suppressed. ULK1 activation occurred following disassociation from its repressor adenine monophosphate activated protein kinase (AMPK), and was elicited by CDN’S generated by the cGAMP synthase, cGAS. Thus, while CDN’s may initially facilitate STING function, they subsequently trigger negative-feedback control of STING activity, thus preventing the persistent transcription of innate immune genes.
2013-10-10 | GSE51199 | GEO
Project description:We report positional cloning and characterization of a novel Sting allele that fails to activate IFN production in the wild-derived mice of MOLF/Ei strain in response to HSV (Herpes Simplex Virus) and Listeria monocytogenes both in vitro and in vivo. We show that previously uncharacterized mutations in the N-terminal of STING are responsible for low levels of IFN due to failure of MOLF STING to respond to cytosolic STING agonists such as 2’3’cGAMP, 5,6-Dimethylxanthenone-4-acetic acid (DMXAA) or poly(deoxyadenylic-deoxythymidylic) acid (dAdT). Using Next-Generation Sequencing (NGS) for the analysis of DNA-responses in congenic C57BL6.StingMOLF/MOLF (MOLF STING) mouse macrophages, we show that these mutations in MOLF/Ei discriminate in responses between different STING agonists. Macrophages from C57BL6.StingB6/B6¬ (B6 STING), or B6 STING expressing littermates were stimulated as a positive control for STING activation, and STING -/- (STING KO) macrophages served as a negative control.
2016-01-03 | GSE68140 | GEO
Project description:We assessed the global transcriptional changes driven by STING activation with the cyclic dinucleotide 2'3'-cGAMP TH1 and TH9 cells polarized in vitro for 16h and 48h. Our data indicated that STING activation led to an upregulation of Type I Interferon, Interferon Stimulated Genes and pro-inflammatory molecule production that was maintained over time. Furthermore, not only STING activation enhanced the transcription of TH1 and TH9 main effector cytokines (respectively Ifng and Il9) but they also also globally enhanced their differentiation programs.
2022-02-18 | GSE147300 | GEO