RNASeq of human bronchial epithelial (HBE) cells with cGAS-siRNA transfected
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE185523 | GEO | 2022/10/01
REPOSITORIES: GEO
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Project description:The cGAS-STING pathway, a central component of the innate immune system, senses cytosolic DNA and induces interferon-stimulated genes (ISGs) to mediate inflammation. Here we report the unexpected discovery that cGAS senses dysfunctional translation. Purified ribosomes interact with and stimulate recombinant cGAS catalytic activity in vitro. Disruption of the ribosome-associated protein quality control pathway, which detects and resolves ribosome collisions, results in cGAS- and STING-dependent ISG expression, and cause the re-localization of cGAS from the nucleus to the cytosol. Other orthogonal perturbations that lead to elevated levels of collided ribosomes cause re-localization of cGAS as well. Thus, the cGAS-STING pathway senses and responds to translation stress. These findings have implications for the inflammatory responses to viral infection and tumorigenesis, both of which substantially reprogram cellular protein synthesis.
2020-05-26 | GSE151127 | GEO
Project description:The cGAS-STING pathway, a central component of the innate immune system, senses cytosolic DNA and induces interferon-stimulated genes (ISGs) to mediate inflammation. Here we report the unexpected discovery that cGAS senses dysfunctional protein production. Purified ribosomes interact with and stimulate the catalytic activity of recombinant cGAS in vitro. Disruption of the ribosome-associated protein quality control pathway, which detects and resolves ribosome collisions, results in cGAS- and STING-dependent ISG expression, and causes the re-localization of cGAS from the nucleus to the cytosol. Indeed, cGAS preferentially binds collided ribosomes in vitro, and other orthogonal perturbations that lead to elevated levels of collided ribosomes cause re-localization of cGAS as well. Thus, the cGAS-STING pathway senses and responds to translation stress. These findings have implications for the inflammatory responses to viral infection and tumorigenesis, both of which substantially reprogram cellular protein synthesis.
2021-09-09 | PXD019359 | Pride
Project description:DNA derived from the genetic material of pathogens or from cellular DNA damage provides a molecular pattern that can be sensed by pattern-recognition receptors of the mammalian innate immune system. In recent years, the cyclic GMP-AMP synthase (cGAS) protein has been characterized as a primary cytosolic DNA sensor during infection with bacteria, DNA viruses, or retroviruses. While the role of cGAS in downstream immune signaling through STING-TBK1-IRF3 proteins is well-defined, regulatory mechanisms of cGAS activity, such as through post-translational modifications (PTMs), are still an active area of research. Here, we report a comprehensive characterization of cGAS phosphorylations and acetylations in three different cell types. Data-dependent proteomic analyses of immunoaffinity purified cGAS was performed in HEK293T cells under control and DNA-challenged conditions (N = 3 each) and human fibroblasts (HFF) cells under control and HSV-1 infected conditions (N = 4 each) to generate candidate cGAS PTM sites. Using parallel reaction monitoring, a total of 11 PTMs (4 phosphorylations and 7 acetylations) were validated in HEK293T, HFF, and THP-1 cells. Of these, 3 phosphorylations and 5 acetylations have not been previously identified. The functions of these modifications were by generating a series of mutants and measuring cGAS-dependent apoptotic and immune signaling activities.
2020-05-11 | PXD017109 | Pride
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.
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Project description:Viral DNA sensing is an essential component of mammalian innate immune response. Upon binding viral DNA, the cyclic-GMP-AMP synthase (cGAS) catalyzes the production of cyclic dinucleotides to induce type I interferons. However, little is known about how cGAS is homeostatically maintained or regulated upon infection. Here, we define cytoplasmic cGAS interactions with cellular and viral proteins upon herpes simplex virus (HSV-1) infection in primary human fibroblasts. We compare several HSV-1 strains (wild-type, d109, d106) that induce cytokine responses and apoptosis, and place cGAS interactions in the context of temporal proteome alterations using isobaric-labeling mass spectrometry. Follow-up analyses establish a functional interaction between cGAS and 2’-5’-oligoadenylate synthase-like protein OASL. The OAS-like domain interacts with the cGAS Mab21 domain, while the OASL ubiquitin-like domain further inhibits cGAS-mediated interferon response. Our findings explain how cGAS may be inactively maintained in cellular homeostasis, with OASL functioning as a negative feedback loop for cytokine induction.
2018-11-21 | PXD010162 | Pride
Project description:Cytosolic DNA activates cyclic GMP-AMP (cGAMP) synthase (cGAS), an innate immune sensor pivotal in anti-microbial defense, senescence, auto-immunity and cancer. cGAS is considered a sequence-independent DNA sensor with limited access to nuclear DNA because of compartmentalization. However, the nuclear envelope is a dynamic barrier and cGAS is present in the nucleus. Here, we identify determinants of nuclear cGAS localization and activation. We show that nuclear-localized cGAS synthesizes cGAMP and induces innate immune activation of dendritic cells, but cGAMP levels are 200-fold lower than following transfection with exogenous DNA. Using cGAS ChIP-seq and a GFP-cGAS knock-in mouse, we find nuclear cGAS enrichment on centromeric satellite DNA, confirmed by imaging, and to a lesser extent with LINE elements. The non-enzymatic N-terminal domain of cGAS determines nucleo-cytoplasmic localization, enrichment on centromeres and activation of nuclear-localized cGAS. These results reveal a preferential functional association of nuclear cGAS with centromeres.
2019-02-27 | GSE125432 | GEO
Project description:Neutrophil Extracellular Traps (NETs) are structures consisting of chromatin and antimicrobial molecules that are released by neutrophils during a form of regulated cell death called NETosis. NETs trap invading pathogens, promote coagulation and activate myeloid cells to produce Type I interferons (type I IFN), proinflammatory cytokines that regulate the immune system. The mechanism of NET recognition by myeloid cells is not yet clearly identified. Here we show that macrophages and other myeloid cells phagocytose NETs. Once in phagosomes, NETs translocate to the cytosol, where they activate the DNA sensor cyclic GMP-AMP synthase (cGAS) and induce type I IFN expression. cGAS recognizes the DNA backbone of NETs. Interestingly, the NET associated serine protease Neutrophil Elastase (NE) mediates the activation of the pathway. We confirmed that NETs activate cGAS in vivo. Thus, our findings identify cGAS as a major sensor of NETs, mediating the immune activation during infection and in auto-immune diseases.
2021-02-18 | PXD015579 | Pride
Project description:Cytosolic DNA activates cyclic GMP-AMP (cGAMP) synthase (cGAS), an innate immune sensor pivotal in anti-microbial defense, senescence, auto-immunity and cancer. cGAS is considered a sequence-independent DNA sensor with limited access to nuclear DNA because of compartmentalization. However, the nuclear envelope is a dynamic barrier and cGAS is present in the nucleus. Here, we identify determinants of nuclear cGAS localization and activation. We show that nuclear-localized cGAS synthesizes cGAMP and induces innate immune activation of dendritic cells, but cGAMP levels are 200-fold lower than following transfection with exogenous DNA. Using cGAS ChIP-seq and a GFP-cGAS knock-in mouse, we find nuclear cGAS enrichment on centromeric satellite DNA, confirmed by imaging, and to a lesser extent with LINE elements. The non-enzymatic N-terminal domain of cGAS determines nucleo-cytoplasmic localization, enrichment on centromeres and activation of nuclear-localized cGAS. These results reveal a preferential functional association of nuclear cGAS with centromeres.
2019-02-27 | GSE125431 | GEO
Project description:Bacterial biofilms of V. cholerae, V. fischeri, and P. aeruginosa grown on agar we analyzed by MALDI mass spectrometry imaging in negative mode for the detection of cyclic dimeric guanosine monophosphate (c-di-GMP). P. aeruginosa samples were also analyzed in positive mode for the detection of additional metabolites. The presence of c-di-GMP was confirmed by MALDI MSMS of a V. cholerae extract. All raw data files are provided, .imzml datafiles provided as supplementary files.
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2013-12-01 | E-GEOD-52241 | biostudies-arrayexpress