Bloom syndrome protein restrains innate immune sensing of DNA damage by cGAS.
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ABSTRACT:
PROVIDER: PRJNA508771 | ENA |
REPOSITORIES: ENA
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Project description:Cellular innate immune sensors of DNA are essential for host defense against invading pathogens. However, the presence of self-derived DNA inside cells poses a biological risk of triggering an inappropriate immune response. The mechanisms limiting induction of inflammation by self nucleic acids are poorly understood. BLM RecQ like helicase is essential for the maintenance of genome integrity and deficient in Bloom syndrome, a rare genetic disease characterized by genome instability, susceptibility to cancer and immunodeficiency. Here, we show that BLM-deficient cells exhibit a constitutively upregulated inflammatory interferon-stimulated gene (ISG) signature. Restoring BLM expression reverts ISG expression to baseline. ISG expression in BLM-deficient fibroblasts is mediated by the cGAS-STING-IRF3 cytosolic DNA sensing pathway. Increased DNA damage or downregulation of the cytoplasmic exonuclease TREX1 enhances ISG expression in BS fibroblasts, and cytoplasmic micronuclei positive for cGAS are increased in BLM-deficient fibroblasts. Finally, BS patients demonstrate elevated ISG expression in peripheral blood. We conclude that BLM is essential to limit the expression of pro-inflammatory genes resulting from the sensing of DNA damage products by the cGAS-STING-IRF3 pathway. These results reveal an unexpected role for BLM in limiting ISG induction, thus connecting DNA damage to innate immunity, which may contribute to human pathogenesis.
2019-03-26 | GSE123447 | GEO
Project description:Cellular innate immune sensors of DNA are essential for host defense against invading pathogens. However, the presence of self-DNA inside cells poses a risk of triggering unchecked immune responses. The mechanisms limiting induction of inflammation by self-DNA are poorly understood. BLM RecQ-like helicase is essential for genome integrity and is deficient in Bloom syndrome (BS), a rare genetic disease characterized by genome instability, accumulation of micronuclei, susceptibility to cancer, and immunodeficiency. Here, we show that BLM-deficient fibroblasts show constitutive up-regulation of inflammatory interferon-stimulated gene (ISG) expression, which is mediated by the cGAS-STING-IRF3 cytosolic DNA-sensing pathway. Increased DNA damage or down-regulation of the cytoplasmic exonuclease TREX1 enhances ISG expression in BLM-deficient fibroblasts. cGAS-containing cytoplasmic micronuclei are increased in BS cells. Finally, BS patients demonstrate elevated ISG expression in peripheral blood. These results reveal that BLM limits ISG induction, thus connecting DNA damage to cellular innate immune response, which may contribute to human pathogenesis.
| S-EPMC6504208 | biostudies-literature
Project description:Cellular senescence is triggered by various distinct stresses and characterized by a permanent cell cycle arrest. Senescent cells secrete a variety of inflammatory factors, collectively referred to as the senescence-associated secretory phenotype (SASP). The mechanism(s) underlying the regulation of the SASP remains incompletely understood. Here we define a role for innate DNA sensing in the regulation of senescence and the SASP. We find that cyclic GMP-AMP synthase (cGAS) recognizes cytosolic chromatin fragments (CCFs) in senescent cells. The activation of cGAS, in turn triggers the production of SASP factors via Stimulator of interferon genes (STING), thereby promoting paracrine senescence. We demonstrate that diverse stimuli of cellular senescence engage the cGAS-STING pathway in vitro and we show cGAS-dependent regulation of senescence upon irradiation and oncogene activation in vivo. Our findings provide insights into the mechanisms underlying cellular senescence by establishing the cGAS-STING pathway as a crucial regulator of senescence and the SASP.
2017-06-20 | GSE100102 | GEO
Project description:Detection of viruses by innate immune sensors induces protective antiviral immunity. The viral DNA sensor cGAS is necessary for detection of HIV by human dendritic cells and macrophages. However, synthesis of HIV DNA during infection is not sufficient for immune activation. The capsid protein, which associates with viral DNA, has a pivotal role in enabling cGAS-mediated immune activation. We now find that NONO is an essential sensor of the HIV capsid in the nucleus. NONO protein directly binds capsid with higher affinity for weakly pathogenic HIV-2 than highly pathogenic HIV-1. Upon infection, NONO is essential for cGAS activation by HIV and cGAS association with HIV DNA in the nucleus. NONO recognizes a conserved region in HIV capsid with limited tolerance for escape mutations. Detection of nuclear viral capsid by NONO to promote DNA sensing by cGAS reveals an innate strategy to achieve distinction of viruses from self in the nucleus.
2018-09-28 | GSE109554 | GEO
Project description:The DNA sensor cGAS senses cytosolic DNA and catalyzes the production of the cyclicdinucleotide cGAMP, resulting in type I IFN responses. We addressed the functionality of cGAS-mediated DNA sensing in human and murine T-cells. Activated primary CD4+ T-cells expressed cGAS and responded robustly to plasmid DNA by upregulation of ISGs and release of bioactive interferon. In mouse T-cells, cGAS KO ablated sensing of plasmid DNA, and TREX1 KO enabled cells to sense short immunostimulatory DNA. Basal expression of IFIT1 and MX2 was downregulated and upregulated in cGAS KO and TREX1 KO T-cell lines, respectively, compared to parental cells. Despite their intact cGAS sensing pathway, human CD4+ T-cells failed to mount a reverse transcriptase (RT) inhibitor-sensitive immune response following HIV-1 infection. In contrast, infection of human T-cells with HSV-1 that is functionally deficient for the cGAS antagonist pUL41 (HSV-1ΔUL41N) resulted in a cGAS dependent type I IFN response. In accordance with our results in primary CD4+ T-cells, plasmid challenge or HSV-1ΔUL41N inoculation of representative T-cell lines provoked an entirely cGAS-dependent type I IFN response, including IRF3 phosphorylation and expression of ISGs. In contrast, no RT-dependent type I IFN response was detected following transduction of T cell lines with VSV-G-pseudotyped lentiviral or gammaretroviral particles. Together, T-cells are capable to raise a cGAS-dependent cell-intrinsic response to both plasmid DNA challenge or inoculation with HSV-1ΔUL41N. However, HIV-1 infection does not appear to trigger cGAS-mediated sensing of viral DNA in T-cells, possibly by revealing viral DNA of insufficient quantity, length, and/or accessibility to cGAS.
2020-05-19 | GSE150753 | GEO
Project description:Upon recognition of aberrantly located DNA, the innate immune sensor cGAS activates STING/IRF-3-driven antiviral responses. Here we characterized the ability of a specific variant of the cGAS-encoding gene MB21D1, rs610913, to alter cGAS-mediated DNA sensing and viral infection. rs610913 is a frequent G>T polymorphism resulting in a P261H exchange in the cGAS protein. Data from the International Collaboration for the Genomics of HIV suggested that rs610913 nominally associates with HIV-1 acquisition in vivo. Molecular modeling of cGAS(P261H) hinted towards the possibility for an additional binding site for a potential cellular co-factor in cGAS dimers. However, cGAS(WT) or cGAS(P261H)-reconstituted THP-1 cGAS KO cells shared steady-state expression of interferon-stimulated genes (ISGs), as opposed to cells expressing the enzymatically inactive cGAS(G212A/S213A). Accordingly, cGAS(WT) and cGAS(P261H) cells were less susceptible to lentiviral transduction and infection with HIV-1, HSV-1, and Chikungunya virus as compared to cGAS KO- or cGAS(G212A/S213A) cells. Upon DNA challenge, innate immune activation appeared to be mildly reduced upon expression of cGAS(P261H) compared to cGAS(WT). Finally, DNA challenge of PBMCs from donors homozygously expressing rs610913 provoked a trend towards a slightly reduced type I IFN response as compared to PBMCs from GG donors. Taken together, the steady-state activity of cGAS maintains a base-line antiviral state rendering cells more refractory to ISG-sensitive viral infections. rs610913 failed to grossly differ phenotypically from the wild-type gene, suggesting that cGAS(P261H) and wild-type cGAS share a similar ability to sense viral infections in vivo.
2022-05-25 | GSE203334 | GEO
Project description:We profiled transcriptomes in human lung cancer cell line A549 when the expression of Bloom was knockdown by the siRNA specific to Bloom.
2018-09-06 | GSE119512 | GEO
Project description:Spontaneous control of HIV-1 replication in the absence of anti-retroviral therapy (ART) naturally occurs in a small proportion of HIV-1-infected individuals known as elite controllers (EC), likely as a result of improved innate and adaptive immune mechanisms. Previous studies suggest that enhanced cytosolic immune recognition of HIV-1 reverse transcripts in conventional dendritic cells (mDC) from EC enables effective induction of antiviral effector T cell responses. However, the specific molecular circuits responsible for such improved innate recognition of HIV-1 in mDC from these individuals remain unknown. Here, we identified a subpopulation of EC whose mDC displayed higher baseline abilities to respond to intracellular HIV-1 dsDNA stimulation. A computational analysis of transcriptional signatures from such high responder EC, combined with functional studies, suggested cytosolic recognition of HIV-1 dsDNA by cGAS, combined with sensing of viral mRNA by RIG-I after polymerase III-mediated HIV-1 DNA transcription. Together, our work identifies collaborative networks of innate sensing pathways that enhance cell-intrinsic abilities of mDC to induce antiviral innate responses against HIV-1; these observations might be useful for the therapeutic induction of effective antiviral immune responses.
2023-01-11 | GSE218587 | GEO
Project description:The hypothesis tested was that lentiviral driven cGAS expression activates antiviral gene expression. Cells were transduced with lentiviruses expressing cGAS or a control (firefly luciferase). Total RNA was harvested 48 h post-transduction and processed for Illumina BeadArray.
2013-12-01 | E-GEOD-52241 | biostudies-arrayexpress
Project description:Loss of SAMHD1 causes chronic activaiton of the MDA5/MAVS dsRNA sensing pathway, only when cGAS/STING signaling is intact.
2022-08-18 | GSE211209 | GEO