Expression Of IFN-stimulated Genes Research Articles

Age-related STING suppression in macrophages contributes to increased viral load during influenza a virus infection.

Ageing is a major risk factor that contributes to increased mortality and morbidity rates during influenza A virus (IAV) infections. Macrophages are crucial players in the defense against viral infections and display impaired function during ageing. However, the impact of ageing on macrophage function in response to an IAV infection remains unclear and offers potential insight for underlying mechanisms. In this study, we investigated the immune response of young and aged human monocyte-derived macrophages to two different H1N1 IAV strains. Interestingly, macrophages of aged individuals showed a lower interferon response to IAV infection, resulting in increased viral load. Transcriptomic data revealed a reduced expression of stimulator of interferon genes (STING) in aged macrophages albeit the cGAS-STING pathway was upregulated. Our data clearly indicate the importance of STING signaling for interferon production by applying a THP-1 STING knockout model. Evaluation of mitochondrial function during IAV infection revealed the release of mitochondrial DNA to be the activator of cGAS-STING pathway. The subsequent induction of apoptosis was attenuated in aged macrophages due to decreased STING signaling. Our study provides new insights into molecular mechanisms underlying age-related immune impairment. To our best knowledge, we are the first to discover an age-dependent difference in gene expression of STING on a transcriptional level in human monocyte-derived macrophages possibly leading to a diminished interferon production.

The Antiviral Effects of Heat-Killed Lactococcus lactis Strain Plasma Against Dengue, Chikungunya, and Zika Viruses in Humans by Upregulating the IFN-α Signaling Pathway

The growing risk of contracting viral infections due to high-density populations and ecological disruptions, such as climate change and increased population mobility, has highlighted the necessity for effective antiviral treatment and preventive measures against Dengue virus (DENV), Chikungunya virus (CHIKV), and Zika virus (ZIKV). Recently, there has been increasing attention on the use of probiotics as a potential antiviral option to reduce virus infections. The present study aimed to assess the immunomodulatory effects of heat-killed Lactococcus lactis strain plasma (LC-Plasma) on peripheral blood mononuclear cells (PBMCs) and its subsequent antiviral response against DENV, CHIKV, and ZIKV. To evaluate the immunomodulatory effects of LC-Plasma on PBMCs isolated from healthy individuals, PBMCs were cultured at a density of 2 × 105 cells/well and stimulated with 10 µg/mL of LC-Plasma. LC-plasma-stimulated PBMCs demonstrated elevated interferon-alpha (IFN-α) production and cluster of differentiation 86 (CD86) and human leukocyte antigen-DR isotype (HLA-DR) upregulation, potentially linked to plasmacytoid dendritic cell (pDC) activation. The replication of DENV, CHIKV, and ZIKV was dose-dependently inhibited when Huh-7 cells were stimulated with LC-Plasma-stimulated PBMC supernatant (LCP Sup). IFN-stimulated gene (ISG) expression, including IFN-stimulated gene 15 (ISG15), IFN-stimulated exonuclease gene 20 (ISG20), IFN-induced transmembrane protein 1 (IFITM-1), myxovirus resistance protein A (MxA), and radical S-adenosyl methionine domain-containing protein 2 (RSAD2), was significantly upregulated in LCP Sup-stimulated Huh-7 cells. Findings from this study indicate that LC-Plasma has the potential to induce IFN-α production, leading to an enhancement in the expression of ISGs and contributing to a broad-spectrum antiviral response. Thus, LC-Plasma may serve as a rational adjunctive treatment to ameliorate viral diseases, warranting future clinical trials.

IMMU-19. PRECLINICAL THERAPEUTIC ACTIVITY AND PET IMAGING OF STING AGONIST 8803 IN GLIOBLASTOMA

Abstract STING (stimulator of interferon genes) activation triggers interferon (IFN) release within the tumor microenvironment from myeloid cells and other cell types, inducing proinflammatory anti-tumor immune responses. The small molecule STING agonist, 8803, elicits long-term survival in 56% (QPP4; p=0.0003) to 100% (QPP8; p<0.0001) of mice with orthotopically implanted immune checkpoint-resistant glioblastoma models after 2-3 doses. In humanized mice, in which glioblastoma-cell STING is epigenetically silenced, 8803 therapeutic activity is maintained. The combination therapy of 8803 with anti-PD-1 relatively further enhances survival in immune checkpoint-resistant models. Ex vivo flow cytometry and proteomic sequential multiplex profiling during the therapeutic window demonstrate global immunological reprogramming, specific tumor-antigen immune responses, increased tumor immune effector trafficking, and release of IFN. It has been shown that IFN signaling augments intracellular nucleotide metabolism and increases [18F]-FLT uptake in pancreatic cancer. We evaluated the longitudinal [18F]-FLT uptake in CT-2A-bearing mice using MRI/PET/CT at days 0, 2, and 4 after intratumoral 8803 delivery. Brain images were acquired before and after [18F]-FLT tracer and 8803 administrations. The CT was used for PET attenuation/correction, and the MRI was used for tumor segmentation. Regional analysis of PET-derived [18F]-FLT SUV maps used advanced image processing approaches as a function of time to enhance the voxel-by-voxel interpretation of the acquired images. [18F]-FLT uptake increased from baseline in all mice treated with 8803 compared to control mice with a peak at 48-96 hours. Concordant sequential multiplex immunofluorescence demonstrated that the STING expression was prominent along the tumor vasculature, myeloid, and tumor cells. p-IRF-3 expression, reflective of STING pathway activation, showed a diffuse pattern after treatment. Based on the preclinical data, PET imaging at 48-96 hours post-treatment represents the appropriate imaging modality and timepoint to maximize the ability to detect STING-dependent changes for a therapeutic strategy that reprograms the glioblastoma microenvironment and improves survival across multiple preclinical models of glioblastoma.

IMMU-54. THERAPEUTIC TARGETING OF STING IN MENINGIOMAS

Abstract Up to one-quarter of meningiomas recur within five years of resection; however, there are currently no established adjuvant therapies for lesions that are intractable to surgery and radiation. To identify novel treatment approaches, scRNA-sequencing datasets were reanalyzed from thirteen meningiomas and nine adjacent dura samples including >30,000 immune cells from varying WHO grades and molecular subtypes. In contrast to gliomas, immune-inducing STING (stimulator of interferon genes) was expressed within the meningioma tumor cells, consistent with DNA methylation profiling that showed hypomethylation of the STING promotor in 93% of cases (267 of 288 meningiomas; beta < 0.2). Meningiomas in the immune-enriched subgroup additionally exhibited significant hypomethylation in the 3’ UTR of this gene (p = 1.9 x 10-9). Using sequential multiplex immune fluorescence, STING expression was confirmed in neoplastic, myeloid, and endothelial cells within all grades of meningiomas, but not in adjacent dura and brain. Downstream STING pathway activation markers such as p-IRF3 were partially expressed, suggesting that further activation of the STING pathway may offer therapeutic benefits. Ex vivo single-cell suspensions of resected human meningiomas treated with the STING agonist 8803 induced 25-45% growth inhibition in 7/8 cases within 72 hours (p < 0.001; two-way ANOVA). There was no growth inhibition of the meningioma cell lines IOMM-LEE and CH157 treated with 8803, which lack immune cells and contain only clonal neoplastic cells. However, when the IOMM-LEE meningioma cells were implanted in vivo, a single dose of 8803 induced a >50% reduction in tumor volume relative to the vehicle control injection at multiple time points (p < 0.001; two-way ANOVA) indicating that the immune system is an essential component of STING efficacy in these tumors. Our results reveal widespread expression of STING in neoplastic and myeloid populations in meningiomas and clarify a new treatment indication for use of the STING agonist 8803.

TMOD-32. MURINE MODELLING OF THE STING PATHWAY IN GLIOMAS

Abstract The stimulator of interferon genes (STING) pathway is a critical component of innate antitumor immunity through the recognition of pathogenic cytosolic DNA and stimulating the production of type 1 interferons and pro-inflammatory cytokines. We have previously shown that STING signaling is silenced in the neoplastic compartment of the GBM tumor microenvironment, but remains intact in vascular and immune cells. In human patient derived cell lines, such silencing appears to be mediated by hypermethylation of a region of the STING promoter and can be reversed by treatment with both the DNA methyltransferase (DNMT) inhibitor Decitabine and DNMT1-selective inhibitor GSK-3685032. These results suggest that neoplastic cell STING promoter methylation represents a therapeutic vulnerability that can be exploited by epigenetic therapies to inflame the glioma tumor microenvironment. Murine models are critical tools for exploring the translational implications of STING silencing in vivo. Distinct mouse models have been developed to optimally represent specific aspects of human glioma biology. Here we characterize the STING pathway in commonly used syngeneic murine glioma models, including CT2A, GL261, SB28, and SMA560. We show that the expression of STING pathway components varies significantly across these lines. Importantly, unlike in humans, murine STING (mSTING) expression is not suppressed by promoter methylation and does not respond to decitabine treatment. Additionally, the mSTING protein is expressed in neoplastic cells in vivo. These results demonstrate a fundamental difference in epigenetic regulation of STING between human and murine glioma cells, and suggest that murine modeling of STING epigenetics requires the use of patient derived cell lines implanted in immunodeficient mice. Meanwhile, immune competent syngeneic models are appropriate for exploring the tumor immune microenvironment but would require non-epigenetic approaches (e.g. genetic knock-outs/knock-ins) for modulating STING expression. Humanized mice represent a promising emerging approach for faithfully recapitulating both epigenetic control and immune environment of human gliomas.

MPXV infection impairs IFN response but is partially sensitive to IFN-γ antiviral effect.

The recent outbreak of monkeypox virus (MPXV) has caused global concern. How the virus evades the interferon (IFN) response is still poorly understood. We analyzed type I/II IFN (IFN-I/II) expression in clinical samples from MPXV-infected patients and measured IFN-I kinetics in MPXV-infected cells. We also evaluated the anti-MPXV activity of IFN-I/II in A549, HeLa and Vero-E6 cell lines. IFN-I/II mRNA expression was detected in skin lesions, anal swabs, nasopharyngeal samples and peripheral blood mononuclear cells (PBMC), with the highest levels in skin lesions (p < 0.05). High MPXV DNA levels in clinical samples were associated with increased IFN-I levels. In vitro, MPXV infection induced a peak of IFN-I between 48 and 72h post-infection (p < 0.01). Pre-treatment of the A549, HeLa and Vero-E6 cells with high concentrations (≥ 100,000 International Unit, IU/ml) of IFN-α and IFN-ω did not inhibit or had little effect on MPXV replication, while IFN-β moderately reduced MPXV replication by 2.7-1.5 log10 at 100,000 IU/ml. In clinical samples there was a trend for elevated levels of IFN-γ in association with lower MPXV load and in vitro IFN-γ (3,600 IU/ml) strongly reduced viral titers by 3.4-1.6 log10. There were no significant differences in expression of select IFN-stimulated genes (ISGs) in MPXV infection in vitro. This study shows that MPXV delays IFN-I induction and inhibits expression of selected ISGs in vitro and is associated with an IFN-I resistance phenotype in vivo. However, MPXV is less resistant to IFN-γ in vivo and is sensitive to IFN-γ treatment in vitro, suggesting a potential therapeutic role for IFN-γ.

Common Cold Coronavirus 229E Induces Higher Interferon Stimulating Gene Responses in Human Nasal Epithelial Cells from Patients with Chronic Rhinosinusitis with Polyposis.

Viral infections have long been implicated in the development of chronic rhinosinusitis with nasal polyps (CRSwNP). Given widespread exposure to the common cold coronavirus 229E (HCoV229E), we sought to investigate how HCoV-229E is cleared and stimulates interferon pathways in air-liquid interface (ALI) cultures from patients with CRSwNP. The objective of this study was to identify whether viral clearance and ISG expression is different in ALI cultures from donors with CRSwNP compared with controls. Plaque assays were used to quantify infectious virus released by infected air-liquid interface (ALI) cultures derived from patients with CRSwNP compared to patients without CRS (controls). Additionally, mock and induced levels of Interferon Stimulated Genes (ISGs) mRNA following HCoV-229E infection were quantified by RT-qPCR. Quantification of infectious virus by plaque assay reveals that CRSwNP ALI cultures were equally susceptible to HCoV-229E infection, and surprisingly viral titers dropped significantly faster than in the control ALI cultures. We further demonstrate that this accelerated viral clearance correlates with increased mRNA expression of at least 4 ISGs following viral infection in the CRSwNP ALIs compared to the control ALIs. This study paradoxically demonstrates that ALI cultures from patients with CRSwNP are more efficient at clearing the common cold HCoV-229E virus compared to controls. We also demonstrate significantly increased ISG mRNA expression following HCoV-229E infection in CRSwNP. These findings call for further investigation into the effect of unimpaired interferon signaling on the type 2 inflammatory environment in patients with CRSwNP.

The long non-coding RNA lncRNA-DRNR enhances infectious bronchitis virus replication by targeting chicken JMJD6 and modulating interferon-stimulated genes expression via the JAK-STAT signalling pathway.

Infectious bronchitis virus (IBV) is the causative agent of infectious bronchitis (IB), a severe disease that primarily affects young chickens and poses a significant challenge to the global poultry industry. Understanding the complex interaction between the virus and its host is vital for developing innovative antiviral strategies. Long non-coding RNA (lncRNA) plays a crucial role in regulating host antiviral immune responses. Our previous studies have shown that IBV infection disrupts the stability of lncRNA in host cells, indicating a potential regulatory role for lncRNA in IBV pathogenesis. It is still not clear how lncRNA precisely modulates IBV replication. In this study, we observed down-regulation ofMSTRG.26120.58 (named lncRNA-DRNR) expression in various chicken cell lines upon IBV infection. We demonstrated that silencing lncRNA-DRNR using siRNA enhances intracellular replication of IBV. Through exploring genes encoding proteins upstream and downstream of lncRNA-DRNR within a 100kb range, we identified chJMJD6 (chicken JMJD6) as a potential target gene negatively regulated by lncRNA-DRNR expression levels. Furthermore, chJMJD6 inhibits STAT1 methylation, thereby affecting the induction of interferon-stimulated genes (ISGs) through the activation of the IFN-β-mediated JAK-STAT signalling pathway, ultimately promoting the intracellular replication of IBV. In summary, our findings reveal the critical role played by lncRNA-DRNR during IBV infection, providing novel insights into mechanisms underlying coronavirus-induced disruption in lncRNA stability.

Marek’s disease virus inhibits the JAK-STAT signaling pathway to evade the innate immune response1

The Janus kinase (JAK)–signal transducer and activator of transcription (STAT) signaling pathway plays a crucial role in innate immunity by inducing antiviral proteins in response to interferon signals. Marek’s disease virus (MDV), a member of the alpha-herpes virus family, exerts potent tumorigenic and immunosuppressive effects. Recent studies have primarily focused on the tumorigenic mechanisms of MDV, and the mechanism of immune evasion has not been fully understood. In this study, we showed that MDV reduced the production of interferon-stimulated gene (ISGs) by inhibiting the phosphorylation and nuclear translocation of STAT1. Using a dual-luciferase reporter system, we screened for viral proteins that significantly suppress interferon-stimulated response element (ISRE) promoter activity. Meq overexpression markedly reduced ISRE promoter activity and ISG expression, whereas infection with Meq-deficient MDV induced higher ISG production in vitro and in vivo than infection with wild-type MDV. Meq also inhibited the phosphorylation and nuclear translocation of STAT1. Further experiments showed that Meq interacted with JAK1 and tyrosine kinase 2 (TYK2) and thereby inhibited JAK1–STAT1 interactions. Meq degraded TYK2 via a caspase-mediated pathway. The Meq-deficient MDV mutant replicated less efficiently than the wild-type MDV, both in vitro and in vivo. Collectively, these findings demonstrate that Meq played an immunosuppressive role in MDV by attenuating the JAK–STAT signaling pathway, which facilitated escape from innate immune-surveillance mechanisms.

PARP7i Clinical Candidate RBN-2397 Exerts Antiviral Activity by Modulating Interferon-β Associated Innate Immune Response in Macrophages.

Polyadenosine diphosphate-ribose polymerase 7 (PARP7) acts as a suppressor of the type I interferon (IFN) signaling pathway via suppressing TANK-binding protein 1 (TBK1). Research study indicates that inhibition of PARP7 could potentially regulate tumor immunity. However, the effect of PARP7 inhibition on innate antiviral immunity in macrophages as well as the underlying mechanism have not been demonstrated else well. We report herein that PARP7 inhibitor clinical candidate RBN-2397 could augment type I interferon (IFN-I) production in macrophages by elevating retinoic acid-inducible gene I (RIG-I) and stimulator of interferon genes (STING) signaling pathways. Treatment with RBN-2397 leads to increased pattern recognition ligands-induced interferon-β production in primary bone marrow-derived macrophages (BMDM) and RAW264.7 cells. Additionally, RBN-2397 suppresses viral replication efficiency in macrophages infected by vesicular stomatitis virus (VSV) and amplifies the expression of interferon-stimulated chemokine genes (ISGs). Mechanistically, RBN-2397 promotes TBK1 phosphorylation, consequently leading to the amplified activation of RIG-I and STING signaling pathways. Furthermore, RBN-2397 enhances the phosphorylation of signal transducer and activator of transcription 1 (STAT1) and STAT2 induced by IFN-α/β and the expression of chemokine genes in macrophages in response to IFN stimulation. In vivo experiments demonstrated that RBN-2397 enhances innate antiviral immunity in mice infected with VSV, resulting in increased serum IFN-β levels, reduced viral loads, and alleviated pulmonary inflammatory responses of the VSV-infected mice. In conclusion, our findings highlight the potential of RBN-2397 as a promising antiviral therapeutic agent for enhancing the IFN-relative antiviral immune defense in host.

IFI27 inhibits HIV-1 replication by degrading Gag protein through the ubiquitin-proteasome pathway.

Type I interferon (IFN-I) and its downstream genes play a profound role in HIV infection. In this study, we found that an IFN-inducible gene, IFI27, was upregulated in HIV-1 infection, which in turn efficiently suppressed HIV-1 replication, specially degraded the viral gag protein, including p24 and p55 subunits. Notably, the anti-HIV-1 activity of IFI27 in Old World monkeys surpassed that in New World monkeys, and IFI27 has a higher potentially inhibitory effect on HIV-1 than simian immunodeficiency virus (SIV). Our initial observations showed that NPM-IFI27, the IFI27 variant in northern pig-tailed macaque (Macaca leonina, NPM), exhibited a strong anti-HIV-1 activity. Further investigation demonstrated that NPM-IFI27 degraded p24 and p55 via the ubiquitin-proteasome pathway, with NPM-IFI27-37-115 interacting with the p24-N domain, and the NPM-IFI27-76-122 domain was closely associated with K48 ubiquitin recruitment. Additionally, Skp2 was identified as the probable E3 ubiquitin ligase responsible for the degradation of p24 and p55. Similarly, human IFI27 (Hu-IFI27) showed a mechanism similar to NPM-IFI27 in HIV-1 inhibition. These findings underscore the pivotal role of NPM-IFI27 in HIV-1 infection and provide a potential strategy for clinical anti-HIV-1 therapy.IMPORTANCEHIV-1 infection can trigger the production of IFN-I, which subsequently activates the expression of various IFN-stimulated genes (ISGs) to antagonize the virus. Therefore, discovering novel host antiviral agents for HIV-1 treatment is crucial. Our previous study revealed that IFI27 can influence HIV-1 replication. In this study, we observed that the NPM-IFI27 complex specifically inhibited HIV-1 by targeting its Gag protein. Further exploration demonstrated that IFI27 interacted with the HIV-1 p24 and p55 proteins, leading to their degradation through the ubiquitin-proteasome pathway. Notably, the NPM-IFI27-37-122 variant exhibited potent anti-HIV-1 activity, comparable to that of SAMHD1. These findings highlight the critical role and inhibitory mechanism of NPM-IFI27 in HIV-1 infection, providing a potential strategy for clinical antiviral therapy.

Metabolic reprogramming tips vaccinia virus infection outcomes by stabilizing interferon-γ induced IRF1.

Interferon (IFN) induced activities are critical, early determinants of immune responses and infection outcomes. A key facet of IFN responses is the upregulation of hundreds of mRNAs termed interferon-stimulated genes (ISGs) that activate intrinsic and cell-mediated defenses. While primary interferon signaling is well-delineated, other layers of regulation are less explored but implied by aberrant ISG expression signatures in many diseases in the absence of infection. Consistently, our examination of tonic ISG levels across uninfected human tissues and individuals revealed three ISG subclasses. As tissue identity and many comorbidities with increased virus susceptibility are characterized by differences in metabolism, we characterized ISG responses in cells grown in media known to favor either aerobic glycolysis (glucose) or oxidative phosphorylation (galactose supplementation). While these conditions over time had a varying impact on the expression of ISG RNAs, the differences were typically greater between treatments than between glucose/galactose. Interestingly, extended interferon-priming led to divergent expression of two ISG proteins: upregulation of IRF1 in IFN-γ/glucose and increased IFITM3 in galactose by IFN-α and IFN-γ. In agreement with a hardwired response, glucose/galactose regulation of interferon-γ induced IRF1 is conserved in unrelated mouse and cat cell types. In galactose conditions, proteasome inhibition restored interferon-γ induced IRF1 levels to that of glucose/interferon-γ. Glucose/interferon-γ decreased replication of the model poxvirus vaccinia at low MOI and high MOIs. Vaccinia replication was restored by IRF1 KO. In contrast, but consistent with differential regulation of IRF1 protein by glucose/galactose, WT and IRF1 KO cells in galactose media supported similar levels of vaccinia replication regardless of IFN-γ priming. Also associated with glucose/galactose is a seemingly second block at a very late stage in viral replication which results in reductions in herpes- and poxvirus titers but not viral protein expression. Collectively, these data illustrate a novel layer of regulation for the key ISG protein, IRF1, mediated by glucose/galactose and imply unappreciated subprograms embedded in the interferon response. In principle, such cellular circuitry could rapidly adapt immune responses by sensing changing metabolite levels consumed during viral replication and cell proliferation.

SARS-CoV-2 variants induce increased inflammatory gene expression but reduced interferon responses and heme synthesis as compared with wild type strains

SARS-CoV-2 variants of concern (VOC) have been associated with increased viral transmission and disease severity. We investigated the mechanisms of pathogenesis caused by variants using a host blood transcriptome profiling approach. We analysed transcriptional signatures of COVID-19 patients comparing those infected with wildtype (wt), alpha, delta or omicron strains seeking insights into infection in Asymptomatic cases.Comparison of transcriptional profiles of Symptomatic and Asymptomatic COVID-19 cases showed increased differentially regulated gene (DEGs) of inflammatory, apoptosis and blood coagulation pathways, with decreased T cell and Interferon stimulated genes (ISG) activation. Between SARS-CoV-2 strains, an increasing number of DEGs occurred in comparisons between wt and alpha (196), delta (1425) or, omicron (2313) infections. COVID-19 cases with alpha or, delta variants demonstrated suppression transcripts of innate immune pathways. EGR1 and CXCL8 were highly upregulated in those infected with VOC; heme biosynthetic pathway genes (ALAS2, HBB, HBG1, HBD9) and ISGs were downregulated. Delta and omicron infections upregulated ribosomal pathways, reflecting increased viral RNA translation. Asymptomatic COVID-19 cases infected with delta infections showed increased cytokines and ISGs expression. Overall, increased inflammation, with reduced host heme synthesis was associated with infections caused by VOC infections, with raised type I interferon in cases with less severe disease.

STING-mediated DNA damage response in diabetes-induced vascular complications

Abstract Background Hyperglycemia drives endothelial dysfunction, a key factor in the development of diabetes vascular complications. The stimulator of interferon genes (STING) signal, plays a crucial role in the immune system and is implicated in the pathogenesis of inflammatory diseases. Therefore we investigated the role of STING in endothelial dysfunction in streptozotocin (STZ)-induced diabetic mice. Methods and Results Diabetes was induced by single-dose administration of STZ in 8-week-old C57BL/6 and Sting-/- mice. STZ injection promoted the expression of STING and DNA damage markers in the aorta of C57BL/6 mice. Genetic deletion of STING ameliorated endothelial dysfunction as determined by vascular reactivity assay (P &amp;lt; 0.001) and increased aortic eNOS phosphorylation (P &amp;lt; 0.05) in STZ-injected mice. Stimulation of STING agonist (cGAMP), or mtDNA increased inflammatory molecules expression (e.g., VCAM1 and IFNB) and decreased eNOS phosphorylation in HUVECs. In ex-vivo experiments, cGAMP significantly impaired endothelial function which was ameliorated in the presence of an STING inhibitor or a neutralizing IFN-β antibody. Furthermore, the administration of STING inhibitor ameliorated endothelial dysfunction in STZ-induced diabetic mice (P &amp;lt; 0.01). Conclusion The DNA damage response regulated by STING aggravated diabetes-induced endothelial dysfunction. STING signaling may be a potential therapeutic target for diabetic vascular complications.

Interferon Epsilon-Mediated Antiviral Activity Against Human Metapneumovirus and Respiratory Syncytial Virus

Background: Interferon epsilon (IFN-ε) is a type I IFN that plays a critical role in the host immune response against pathogens. Despite having demonstrated antiviral activity in macrophages and mucosal tissues such as the female reproductive tract and the constitutive expression in mucosal tissues such as the lung, the relevance of IFN-ε against respiratory viral infections remains elusive. Results: We present, for the first time, the expression of IFN-ε in alveolar epithelial cells and primary human bronchial epithelial cells grown in an air–liquid interface (ALI) in response to human metapneumovirus (HMPV) and respiratory syncytial virus (RSV) infection. The molecular characterization of the IFN-ε induction by the viruses indicates that the expression of RIG-I is necessary for an optimal IFN-ε expression. Furthermore, treatment of the airway epithelial cells with rhIFN-ε induced the expression of IFN-stimulated genes (ISGs) and significantly restricted the viral replication of HMPV and RSV. Conclusions: These findings underscore the relevance of IFN-ε against viral infections in the respiratory tract.

Suppressing Pancreatic Cancer Survival and Immune Escape via Nanoparticle-Modulated STING/STAT3 Axis Regulation.

Pancreatic ductal adenocarcinoma (PDAC) poses a challenge in oncology due to its high lethality and resistance to immunotherapy. Recently, emerging research on the stimulator of interferon gene (STING) pathway offers novel opportunities for immunotherapy. Although STING expression is retained in PDAC cells, the response of PDAC cells to STING agonists remains ineffective. Signal transducer and activator of transcription 3 (STAT3), a downstream pathway of STING, is notably overexpressed in pancreatic cancer and related to tumor survival and immune escape. We observed that inhibiting STAT3 signaling post-STING activation effectively suppressed tumor growth through signal transducer and activator of transcription 1 (STAT1)-mediated apoptosis but led to a potential risk of immune-related adverse events (irAEs). To address this issue, we designed a tumor-penetrating liposome for the codelivery of STING agonist and STAT3 inhibitor. These nanoparticles regulated the STING/STAT3 signaling axis and effectively inhibited the proliferation and survival of tumor. Simultaneously, we found a significant increase in the activation of NK cells and CD8+ T cells after treatment, leading to robust innate immunity and adaptive immune response. We highlight the potential of regulating the STING/STAT3 axis as a promising treatment for improving clinical outcomes in PDAC patients.

Metabolic reprogramming tips vaccinia virus infection outcomes by stabilizing interferon-γ induced IRF1.

Interferon (IFN) induced activities are critical, early determinants of immune responses and infection outcomes. A key facet of IFN responses is the upregulation of hundreds of mRNAs termed interferon-stimulated genes (ISGs) that activate intrinsic and cell-mediated defenses. While primary interferon signaling is well-delineated, other layers of regulation are less explored but implied by aberrant ISG expression signatures in many diseases in the absence of infection. Consistently, our examination of tonic ISG levels across uninfected human tissues and individuals revealed three ISG subclasses. As tissue identity and many comorbidities with increased virus susceptibility are characterized by differences in metabolism, we characterized ISG responses in cells grown in media known to favor either aerobic glycolysis (glucose) or oxidative phosphorylation (galactose supplementation). While these conditions over time had a varying impact on the expression of ISG RNAs, the differences were typically greater between treatments than between glucose/galactose. Interestingly, extended interferon-priming led to divergent expression of two ISG proteins: upregulation of IRF1 in IFN-γ/glucose and increased IFITM3 in galactose by IFN-α and IFN-γ. In agreement with a hardwired response, glucose/galactose regulation of interferon-γ induced IRF1 is conserved in unrelated mouse and cat cell types. In galactose conditions, proteasome inhibition restored interferon-γ induced IRF1 levels to that of glucose/interferon-γ. Glucose/interferon-γ decreased replication of the model poxvirus vaccinia at low MOI and high MOIs. Vaccinia replication was restored by IRF1 KO. In contrast, but consistent with differential regulation of IRF1 protein by glucose/galactose, WT and IRF1 KO cells in galactose media supported similar levels of vaccinia replication regardless of IFN-γ priming. Also associated with glucose/galactose is a seemingly second block at a very late stage in viral replication which results in reductions in herpes- and poxvirus titers but not viral protein expression. Collectively, these data illustrate a novel layer of regulation for the key ISG protein, IRF1, mediated by glucose/galactose and imply unappreciated subprograms embedded in the interferon response. In principle, such cellular circuitry could rapidly adapt immune responses by sensing changing metabolite levels consumed during viral replication and cell proliferation.

The Type 1 Diabetes-Associated Single Nucleotide Polymorphism rs1990760 in IFIH1 Is Associated with Increased Basal Type I IFNs and IFN-stimulated Gene Expression.

Type 1 diabetes (T1D) is a chronic autoimmune disease that is caused by a combination of genetic and environmental risk factors. In this study, we sought to determine whether a known genetic risk factor, the rs1990760 single nucleotide polymorphism (SNP) (A946T) in IFIH1, resulted in a gain of function in the MDA5 protein and the effects of this mutation on the regulation of type I IFNs during infection with the diabetogenic virus coxsackievirus B3. We found that in cell lines overexpressing the risk variant IFIH1946T there was an elevated level of basal type I IFN signaling and increased basal IFN-stimulated gene expression. An investigation into the mechanism demonstrated that recombinant MDA5 with the A946T mutation had increased ATPase activity invitro. We also assessed the effect of this SNP in primary human PBMCs from healthy donors to determine whether this SNP influenced their response to infection with coxsackievirus B3. However, we observed no significant changes in type I IFN expression or downstream induction of IFN-stimulated genes in PBMCs from donors carrying the risk allele IFIH1946T. These findings demonstrate the need for a deeper understanding of how mutations in T1D-associated genes contribute to disease onset in specific cellular contexts.

Nuclear PCGF3 inhibits the antiviral immune response by suppressing the interferon-stimulated gene

Type I interferon (IFN-I) plays a crucial role in the antiviral immune response and inflammatory autoimmune diseases by inducing the expression of IFN-stimulated genes (ISGs). Hence, the regulation of ISG expression is fundamental for maintaining immune homeostasis. In this study, we found that PCGF3 negatively regulates the antiviral response by suppressing the expression of ISGs. The deficiency of PCGF3 in innate immune cells results in an augmented expression of ISGs in response to IFN-I stimulation. Mechanistically, PCGF3 is recruited to interferon-stimulated response elements (ISREs) region in an IFN-dependent way, precluding STAT1 from binding to the ISG promoter and diminishing ISRE activity. Additionally, we observed a negative correlation between decreased PCGF3 expression and elevated ISG expression in peripheral blood mononuclear cells (PBMCs) of patients with dermatomyositis (DM). Our findings clarified the epigenetic regulatory role of PCGF3 in inhibiting the excessive expression of ISGs induced by IFN-I under pathological circumstances.

Expression of interferon-stimulated genes, but not polymorphisms in the interferon α/β receptor 2 gene, is associated with coronavirus disease 2019 mortality

Excessive inflammatory response is a hallmark of severe COVID-19. This study investigated the associations between interferon-stimulated genes (ISGs) expression, genetic variation in the interferon α/β receptor 2 (IFNAR2) gene, and COVID-19 mortality.We investigated 67 patients with moderate-to-severe COVID-19. Of them, 22 patients (32.8 %) died because of COVID-19. We examined the expression of ISGs in total RNA of peripheral whole blood. We observed a significant increase in the expression of all ISGs examined in non-surviving patients, indicating a heightened interferon type I signaling activation in non-survived patients. Subsequently, we analyzed whether the increase in ISGs expression was correlated with polymorphism within the IFNAR2 gene. Intriguingly, no significant association was observed between IFNAR2 gene polymorphism and COVID-19 mortality. Similarly, no association was noted between the IFNAR2 and ISGs expression levels.Overall, our data showed that higher ISGs expression, which presumably indicates heightened interferon type I activation, is associated with COVID-19 mortality.