Interferon-Independent Activities of Mammalian STING Mediate Antiviral Response and Tumor Immune Evasion.
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ABSTRACT:
SUBMITTER: Wu J
PROVIDER: S-EPMC7365768 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Type I interferon (IFN) response is the most recognized signaling activity of STING, and IFN signaling is commonly believed to be the major (if not the sole) contributor to STING-mediated anti-viral and anti-cancer responses. Here, we genetically mutated mouse Sting serine 365 residue that is critically required for initiating IFN signaling. Sting-S365A mutation in mice precisely ablated IFN-dependent while preserving IFN-independent activities of STING. To our surprise, StingS365A/S365A mice protected against HSV-1 infection remarkably well, similar to wild type mice, while Sting–/– mice succumbed to infection very quickly. This challenges the current prevailing view and suggests that STING controls HSV-1 infection through IFN-independent activities. Transcriptomic analysis of wild type, Sting–/– and StingS365A/S365A macrophages and T cells stimulated with Sting agonist DMXAA revealed widespread IFN-independent activities of STING in both cell types and identified many T cell effector functions that are activated by STING independently of IFN. In mouse tumor models, we found that T cells in the tumor experience substantial cell death that was in part mediated by STING. Adoptively transferred Sting–/– T cells were more resistant to cell death in the tumor leading to more effective tumor control compared to wild type and StingS365A/S365A T cells. Together, our data demonstrate that mammalian STING possesses widespread IFN-independent activities that are functionally important for restricting Type I interferon (IFN) response is the most recognized signaling activity of STING, and IFN signaling is commonly believed to be the major (if not the sole) contributor to STING-mediated anti-viral and anti-cancer responses. Here, we genetically mutated mouse Sting serine 365 residue that is critically required for initiating IFN signaling. Sting-S365A mutation in mice precisely ablated IFN-dependent while preserving IFN-independent activities of STING. To our surprise, StingS365A/S365A mice protected against HSV-1 infection remarkably well, similar to wild type mice, while Sting–/– mice succumbed to infection very quickly. This challenges the current prevailing view and suggests that STING controls HSV-1 infection through IFN-independent activities. Transcriptomic analysis of wild type, Sting–/– and StingS365A/S365A macrophages and T cells stimulated with Sting agonist DMXAA revealed widespread IFN-independent activities of STING in both cell types and identified many T cell effector functions that are activated by STING independently of IFN. In mouse tumor models, we found that T cells in the tumor experience substantial cell death that was in part mediated by STING. Adoptively transferred Sting–/– T cells were more resistant to cell death in the tumor leading to more effective tumor control compared to wild type and StingS365A/S365A T cells. Together, our data demonstrate that mammalian STING possesses widespread IFN-independent activities that are functionally important for restricting HSV-1 infection, tumor immune evasion and likely also adaptive T cell immunity.
2020-07-07 | GSE149744 | GEO
Project description:Widespread IFN-independent activities of mammalian STING in viral infection and tumor immune evasion
| PRJNA629829 | ENA
Project description:The cellular DNA sensor cGMP-AMP synthase (cGAS) detects cytosolic viral DNA via the stimulator of interferon genes (STING) to initiate innate antiviral response. Herpesviruses are known to target key immune signaling pathways to persist in an immune-competent host. Marek's disease virus (MDV), a highly pathogenic and oncogenic herpesvirus of chickens, can antagonize host innate immune responses to achieve persistent infection. With a functional screen, we identified five MDV proteins that blocked beta interferon (IFN-?) induction downstream of the cGAS-STING pathway. Specifically, the MDV major oncoprotein Meq impeded the recruitment of TANK-binding kinase 1 and IFN regulatory factor 7 (IRF7) to the STING complex, thereby inhibiting IRF7 activation and IFN-? induction. Meq overexpression markedly reduced antiviral responses stimulated by cytosolic DNA, whereas knockdown of Meq heightened MDV-triggered induction of IFN-? and downstream antiviral genes. Moreover, Meq-deficient MDV induced more IFN-? production than wild-type MDV. Meq-deficient MDV also triggered a more robust CD8+ T cell response than wild-type MDV. As such, the Meq-deficient MDV was highly attenuated in replication and lymphoma induction compared to wild-type MDV. Taken together, these results revealed that MDV evades the cGAS-STING DNA sensing pathway, which underpins the efficient replication and oncogenesis. These findings improve our understanding of the virus-host interaction in MDV-induced lymphoma and may contribute to the development of novel vaccines against MDV infection.
| S-EPMC6799934 | biostudies-literature
Project description:Interferon-induced proteins with tetratricopeptide repeats (IFITs) are involved in the protective response to viral infection, although the precise mechanism of IFITs for reducing viral proliferation is currently unknown. The interaction with the translation initiation factor eIF-3 or viral proteins and the sequestering of viral RNA have been proposed as potential antiviral functions for these proteins. In humans, four members of this family have been characterized. Nevertheless, information about these proteins in fish is almost non-existent. Exploiting the conservation of synteny between human and zebrafish genomes, we have identified ten members of the IFIT family located on four different chromosomes. The induction of these genes was examined both in vitro and in vivo after interferon (IFN) administration and rhabdovirus challenge. Whereas an induction of IFIT genes was observed after interferon treatments (IFN?1, IFN?2 and IFN?3), the viral infection did not affect these IFN-induced genes in vitro, and even reduced the IFN-induced expression of these genes. The response was largely different in vivo, with a broad up-regulation of IFIT genes after viral challenge. In addition, three selected IFITs were cloned in an expression vector and microinjected into zebrafish larvae to examine the protective effect of IFITs upon viral infection. Reduction in the mortality rate was observed confirming a conserved antiviral function in non-mammalian species.
| S-EPMC4065003 | biostudies-literature
Project description:Utilization of antiviral small interfering RNAs is thought to be largely restricted to plants, nematodes, and arthropods. In an effort to determine whether a physiological interplay exists between the host small RNA machinery and the cellular response to virus infection in mammals, we evaluated antiviral activity in the presence and absence of Dicer or Drosha, the RNase III nucleases responsible for generating small RNAs. Although loss of Dicer did not compromise the cellular response to virus infection, Drosha deletion resulted in a significant increase in virus levels. Here, we demonstrate that diverse RNA viruses trigger exportin 1 (XPO1/CRM1)-dependent Drosha translocation into the cytoplasm in a manner independent of de novo protein synthesis or the canonical type I IFN system. Additionally, increased virus infection in the absence of Drosha was not due to a loss of viral small RNAs but, instead, correlated with cleavage of viral genomic RNA and modulation of the host transcriptome. Taken together, we propose that Drosha represents a unique and conserved arm of the cellular defenses used to combat virus infection.
| S-EPMC4024876 | biostudies-other
Project description:The ubiquitin regulatory X domain-containing proteins (UBXNs) are likely involved in diverse biological processes. Their physiological functions, however, remain largely unknown. Here we present physiological evidence that UBXN3B positively regulates stimulator-of-interferon genes (STING) signaling. We employ a tamoxifen-inducible Cre-LoxP approach to generate systemic Ubxn3b knockout in adult mice as the Ubxn3b-null mutation is embryonically lethal. Ubxn3b-/-, like Sting-/- mice, are highly susceptible to lethal herpes simplex virus 1 (HSV-1) and vesicular stomatitis virus (VSV) infection, which is correlated with deficient immune responses when compared to Ubxn3b+/+ littermates. HSV-1 and STING agonist-induced immune responses are also reduced in several mouse and human Ubxn3b-/- primary cells. Mechanistic studies demonstrate that UBXN3B interacts with both STING and its E3 ligase TRIM56, and facilitates STING ubiquitination, dimerization, trafficking, and consequent recruitment and phosphorylation of TBK1. These results provide physiological evidence that links the UBXN family with antiviral immune responses.
| S-EPMC5998066 | biostudies-literature
Project description:Immunotherapy offers new options for cancer treatment, but efficacy varies across cancer types. Colorectal cancers (CRCs) are largely refractory to immune-checkpoint blockade, which suggests the presence of yet uncharacterized immune-suppressive mechanisms. Here we report that the loss of adenomatosis polyposis coli (APC) in intestinal tumor cells or of the tumor suppressor PTEN in melanoma cells upregulates the expression of Dickkopf-related protein 2 (DKK2), which, together with its receptor LRP5, provides an unconventional mechanism for tumor immune evasion. DKK2 secreted by tumor cells acts on cytotoxic lymphocytes, inhibiting STAT5 signaling by impeding STAT5 nuclear localization via LRP5, but independently of LRP6 and the Wnt-?-catenin pathway. Genetic or antibody-mediated ablation of DKK2 activates natural killer (NK) cells and CD8+ T cells in tumors, impedes tumor progression, and enhances the effects of PD-1 blockade. Thus, we have identified a previously unknown tumor immune-suppressive mechanism and immunotherapeutic targets particularly relevant for CRCs and a subset of melanomas.
| S-EPMC5840007 | biostudies-literature
Project description:BackgroundImprovement of radiotherapy efficacy requires better insight in the dynamic responses that occur during irradiation. Here, we aimed to identify the molecular responses that are triggered during clinically applied fractionated irradiation.MethodsGene expression analysis was performed by RNAseq or microarray analysis of cancer cells or xenograft tumors, respectively, subjected to 3-5 weeks of 5 × 2 Gy/week. Validation of altered gene expression was performed by qPCR and/or ELISA in multiple cancer cell lines as well as in pre- and on-treatment biopsies from esophageal cancer patients ( NCT02072720 ). Targeted protein inhibition and CRISPR/Cas-induced gene knockout was used to analyze the role of type I interferons and cGAS/STING signaling pathway in the molecular and cellular response to fractionated irradiation.ResultsGene expression analysis identified type I interferon signaling as the most significantly enriched biological process induced during fractionated irradiation. The commonality of this response was confirmed in all irradiated cell lines, the xenograft tumors and in biopsies from esophageal cancer patients. Time-course analyses demonstrated a peak in interferon-stimulated gene (ISG) expression within 2-3 weeks of treatment. The response was accompanied by a variable induction of predominantly interferon-beta and/or -lambda, but blocking these interferons did not affect ISG expression induction. The same was true for targeted inhibition of the upstream regulatory STING protein while knockout of STING expression only delayed the ISG expression induction.ConclusionsCollectively, the presented data show that clinically applied fractionated low-dose irradiation can induce a delayed type I interferon response that occurs independently of interferon expression or STING signaling. These findings have implications for current efforts that aim to target the type I interferon response for cancer treatment.
| S-EPMC8106844 | biostudies-literature
Project description: Not available
| S-BSST1237 | biostudies-other
Project description:Mechanisms by which tumor cells evade detection by the host's immune system are thought to play a role in progression to malignancy, but this has not been investigated in the context of neurofibromatosis type 1 (NF1). NF1 is an autosomal dominant disorder, in which aggressive peripheral nerve tumors, known as malignant peripheral nerve sheath tumors (MPNSTs), develop in 5-10% of patients. Large scale gene expression profiling of a MPNST-derived cell line, T265, and normal human Schwann cells (hSCs) identified a large group of immune function genes down-regulated in T265 cells. Here we report that the aberrant expression of immune system related genes extends beyond MHC class I and II genes in T265 cells to include a transcription factor (MHC2TA) and other critical components of the antigen processing and presentation apparatus. TAP1, the transporter-activator protein that loads peptide antigens onto MHC class I molecules, is down-regulated, and CD74, a chaperone protein whose function is in processing and transport of MHC class II molecules, is down-regulated and alternatively spliced to produce an RNA transcript not evident in normal human Schwann cells. These findings reveal multiple molecular pathways and at least two cellular mechanisms acting to reduce the normal immune system molecules involved in antigen processing and presentation in cells derived from a peripheral nerve sheath tumor. Acquiring a "silent" immune signature may be a critical step in the progress towards malignancy in MPNSTs.
| S-EPMC2265633 | biostudies-other