scholarly journals Type I Interferon-Mediated Regulation of Antiviral Capabilities of Neutrophils

2021 ◽  
Vol 22 (9) ◽  
pp. 4726
Author(s):  
Ashley A. Stegelmeier ◽  
Maedeh Darzianiazizi ◽  
Kiersten Hanada ◽  
Shayan Sharif ◽  
Sarah K. Wootton ◽  
...  
Keyword(s):  
Immune Responses ◽  
Tissue Damage ◽  
Viral Infections ◽  
Neutrophil Extracellular Trap ◽  
Type I ◽  
Novel Treatments ◽  
Immune Resistance ◽  
Infection And Inflammation ◽  
Host Antiviral Response ◽  
Minimize Tissue Damage

Interferons (IFNs) are induced by viruses and are the main regulators of the host antiviral response. They balance tissue tolerance and immune resistance against viral challenges. Like all cells in the human body, neutrophils possess the receptors for IFNs and contribute to antiviral host defense. To combat viruses, neutrophils utilize various mechanisms, such as viral sensing, neutrophil extracellular trap formation, and antigen presentation. These mechanisms have also been linked to tissue damage during viral infection and inflammation. In this review, we presented evidence that a complex cross-regulatory talk between IFNs and neutrophils initiates appropriate antiviral immune responses and regulates them to minimize tissue damage. We also explored recent exciting research elucidating the interactions between IFNs, neutrophils, and severe acute respiratory syndrome-coronavirus-2, as an example of neutrophil and IFN cross-regulatory talk. Dissecting the IFN-neutrophil paradigm is needed for well-balanced antiviral therapeutics and development of novel treatments against many major epidemic or pandemic viral infections, including the ongoing pandemic of the coronavirus disease that emerged in 2019.

TREX1 is a checkpoint for innate immune sensing of DNA damage that fosters cancer immune resistance

2017 ◽  
Vol 1 (5) ◽  
pp. 509-515
Author(s):  
Sandra Demaria ◽  
Claire Vanpouille-Box
Keyword(s):  
Dna Damage ◽  
Immune Responses ◽  
Cancer Cells ◽  
Genomic Instability ◽  
Cancer Progression ◽  
Type I ◽  
Replicative Stress ◽  
Immune Resistance ◽  
Cytoplasmic Dna ◽  
Autoimmune Pathology

Genomic instability is a hallmark of neoplastic transformation that leads to the accumulation of mutations, and generates a state of replicative stress in neoplastic cells associated with dysregulated DNA damage repair (DDR) responses. The importance of increasing mutations in driving cancer progression is well established, whereas relatively little attention has been devoted to the DNA displaced to the cytosol of cancer cells, a byproduct of genomic instability and of the ensuing DDR response. The presence of DNA in the cytosol promotes the activation of viral defense pathways in all cells, leading to activation of innate and adaptive immune responses. In fact, the improper accumulation of cytosolic DNA in normal cells is known to drive severe autoimmune pathology. Thus, cancer cells must evade cytoplasmic DNA detection pathways to avoid immune-mediated destruction. The main sensor for cytoplasmic DNA is the cyclic GMP–AMP synthase, cGAS. Upon activation by cytosolic DNA, cGAS catalyzes the formation of the second messenger cGAMP, which activates STING (stimulator of IFN genes), leading to the production of type I interferon (IFN-I). IFN-I is a critical effector of cell-mediated antiviral and antitumor immunity, and its production by cancer cells can be subverted by several mechanisms. However, the key upstream regulator of cytosolic DNA-mediated immune stimulation is the DNA exonuclease 3′-repair exonuclease 1 (TREX1). Here, we will discuss evidence in support of a role of TREX1 as an immune checkpoint that, when up-regulated, hinders the development of antitumor immune responses.

scholarly journals Mast Cell Responses to Viruses and Pathogen Products

2019 ◽  
Vol 20 (17) ◽  
pp. 4241 ◽  
Author(s):  
Jean S. Marshall ◽  
Liliana Portales-Cervantes ◽  
Edwin Leong
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Immune Responses ◽  
Viral Infection ◽  
Viral Infections ◽  
Inflammatory Responses ◽  
Local Source ◽  
Type I ◽  
Viral Challenge ◽  
Cell Responses

Mast cells are well accepted as important sentinel cells for host defence against selected pathogens. Their location at mucosal surfaces and ability to mobilize multiple aspects of early immune responses makes them critical contributors to effective immunity in several experimental settings. However, the interactions of mast cells with viruses and pathogen products are complex and can have both detrimental and positive impacts. There is substantial evidence for mast cell mobilization and activation of effector cells and mobilization of dendritic cells following viral challenge. These cells are a major and under-appreciated local source of type I and III interferons following viral challenge. However, mast cells have also been implicated in inappropriate inflammatory responses, long term fibrosis, and vascular leakage associated with viral infections. Progress in combating infection and boosting effective immunity requires a better understanding of mast cell responses to viral infection and the pathogen products and receptors we can employ to modify such responses. In this review, we outline some of the key known responses of mast cells to viral infection and their major responses to pathogen products. We have placed an emphasis on data obtained from human mast cells and aim to provide a framework for considering the complex interactions between mast cells and pathogens with a view to exploiting this knowledge therapeutically. Long-lived resident mast cells and their responses to viruses and pathogen products provide excellent opportunities to modify local immune responses that remain to be fully exploited in cancer immunotherapy, vaccination, and treatment of infectious diseases.

scholarly journals Positive regulation of plasmacytoid dendritic cell function via Ly49Q recognition of class I MHC

2008 ◽  
Vol 205 (13) ◽  
pp. 3187-3199 ◽  
Author(s):  
Lee-Hwa Tai ◽  
Marie-Line Goulet ◽  
Simon Belanger ◽  
Noriko Toyama-Sorimachi ◽  
Nassima Fodil-Cornu ◽  
...  
Keyword(s):  
Immune Responses ◽  
Cell Function ◽  
Viral Infections ◽  
Plasmacytoid Dendritic Cell ◽  
Class I ◽  
Type I ◽  
Class I Mhc ◽  
Mhc Molecules

Plasmacytoid dendritic cells (pDCs) are an important source of type I interferon (IFN) during initial immune responses to viral infections. In mice, pDCs are uniquely characterized by high-level expression of Ly49Q, a C-type lectin-like receptor specific for class I major histocompatibility complex (MHC) molecules. Despite having a cytoplasmic immunoreceptor tyrosine-based inhibitory motif, Ly49Q was found to enhance pDC function in vitro, as pDC cytokine production in response to the Toll-like receptor (TLR) 9 agonist CpG-oligonucleotide (ODN) could be blocked using soluble monoclonal antibody (mAb) to Ly49Q or H-2Kb. Conversely, CpG-ODN–dependent IFN-α production by pDCs was greatly augmented upon receptor cross-linking using immobilized anti-Ly49Q mAb or recombinant H-2Kb ligand. Accordingly, Ly49Q-deficient pDCs displayed a severely reduced capacity to produce cytokines in response to TLR7 and TLR9 stimulation both in vitro and in vivo. Finally, TLR9-dependent antiviral responses were compromised in Ly49Q-null mice infected with mouse cytomegalovirus. Thus, class I MHC recognition by Ly49Q on pDCs is necessary for optimal activation of innate immune responses in vivo.

scholarly journals Interferon-Mediated Immunopathological Events Are Associated with Atypical Innate and Adaptive Immune Responses in Patients with Severe Acute Respiratory Syndrome

2007 ◽  
Vol 81 (16) ◽  
pp. 8692-8706 ◽  
Author(s):  
Mark J. Cameron ◽  
Longsi Ran ◽  
Luoling Xu ◽  
Ali Danesh ◽  
Jesus F. Bermejo-Martin ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Immune Responses ◽  
Viral Infections ◽  
Fatal Outcome ◽  
Careful Examination ◽  
Type I ◽  
Immunoglobulin Gene ◽  
Adaptive Immune Responses ◽  
Immune Genes ◽  
Adaptive Immune

ABSTRACT It is not understood how immune inflammation influences the pathogenesis of severe acute respiratory syndrome (SARS). One area of strong controversy is the role of interferon (IFN) responses in the natural history of SARS. The fact that the majority of SARS patients recover after relatively moderate illness suggests that the prevailing notion of deficient type I IFN-mediated immunity, with hypercytokinemia driving a poor clinical course, is oversimplified. We used proteomic and genomic technology to systematically analyze host innate and adaptive immune responses of 40 clinically well-described patients with SARS during discrete phases of illness from the onset of symptoms to discharge or a fatal outcome. A novel signature of high IFN-α, IFN-γ, and IFN-stimulated chemokine levels, plus robust antiviral IFN-stimulated gene (ISG) expression, accompanied early SARS sequelae. As acute illness progressed, SARS patients entered a crisis phase linked to oxygen saturation profiles. The majority of SARS patients resolved IFN responses at crisis and expressed adaptive immune genes. In contrast, patients with poor outcomes showed deviated ISG and immunoglobulin gene expression levels, persistent chemokine levels, and deficient anti-SARS spike antibody production. We contend that unregulated IFN responses during acute-phase SARS may culminate in a malfunction of the switch from innate immunity to adaptive immunity. The potential for the use of the gene signatures we describe in this study to better assess the immunopathology and clinical management of severe viral infections, such as SARS and avian influenza (H5N1), is therefore worth careful examination.

scholarly journals Role of the transcriptional regulator SP140 in resistance to bacterial infections via repression of type I interferons

2020 ◽  
Author(s):  
Daisy X. Ji ◽  
Kristen C. Witt ◽  
Dmitri I. Kotov ◽  
Shally R. Margolis ◽  
Alexander Louie ◽  
...  
Keyword(s):  
Immune Responses ◽  
Legionella Pneumophila ◽  
Bacterial Infections ◽  
Viral Infections ◽  
Transcriptional Regulator ◽  
Type I Interferons ◽  
Type I ◽  
Viral Immunity ◽  
Type I Ifns

AbstractType I interferons (IFNs) are essential for anti-viral immunity, but often impair protective immune responses during bacterial infections. How type I IFNs are strongly induced during viral infections, and yet are appropriately restrained during bacterial infections, remains poorly understood. The Super susceptibility to tuberculosis 1 (Sst1) locus in mice confers resistance to many bacterial infections. Here we provide evidence that Sp140 is a gene encoded within the Sst1 locus that functions to repress the expression of type I IFNs during bacterial infections. We generated Sp140−/− mice and find they are susceptible to infection by diverse bacteria, including Listeria monocytogenes, Legionella pneumophila, and Mycobacterium tuberculosis. Susceptibility of Sp140−/− mice to bacterial infection was rescued by crosses to mice lacking the type I IFN receptor (Ifnar−/−). Our results implicate Sp140 as an important repressor of type I IFNs that is essential for resistance to bacterial infections.

Beyond dsRNA: Toll-like receptor 3 signalling in RNA-induced immune responses

2014 ◽  
Vol 458 (2) ◽  
pp. 195-201 ◽  
Author(s):  
Megumi Tatematsu ◽  
Tsukasa Seya ◽  
Misako Matsumoto
Keyword(s):  
Immune Responses ◽  
Transmembrane Protein ◽  
Wide Spectrum ◽  
Physiological Role ◽  
Structural Features ◽  
Dendritic Cell Maturation ◽  
Type I ◽  
Toll Like Receptor ◽  
Wide Range ◽  
Infection And Inflammation

The innate immune system recognizes pathogen- and damage-associated molecular patterns using pattern-recognition receptors that activate a wide range of signalling cascades to maintain host homoeostasis against infection and inflammation. Endosomal TLR3 (Toll-like receptor 3), a type I transmembrane protein, senses RNAs derived from cells with viral infection or sterile tissue damage, leading to the induction of type I interferon and cytokine production, as well as dendritic cell maturation. It has been accepted that TLR3 recognizes perfect dsRNA, but little has been addressed experimentally with regard to the structural features of virus- or host-derived RNAs that activate TLR3. Recently, a TLR3 agonist was identified, which was a virus-derived ‘structured’ RNA with incomplete stem structures. Both dsRNA and structured RNA are similarly internalized through clathrin- and raftlin-dependent endocytosis and delivered to endosomal TLR3. The dsRNA uptake machinery, in addition to TLR3, is critical for extracellular viral RNA-induced immune responses. A wide spectrum of TLR3 ligand structures beyond dsRNA and their delivery systems provide new insights into the physiological role of TLR3 in virus- or host-derived RNA-induced immune responses. In the present paper, we focus on the system for extracellular recognition of RNA and its delivery to TLR3.

scholarly journals FOSL1 Inhibits Type I Interferon Responses to Malaria and Viral Infections by Blocking TBK1 and TRAF3/TRIF Interactions

mBio ◽  
2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Baowei Cai ◽  
Jian Wu ◽  
Xiao Yu ◽  
Xin-zhuan Su ◽  
Rong-Fu Wang
Keyword(s):  
Immune Responses ◽  
Drug Target ◽  
Malaria Parasite ◽  
Viral Infections ◽  
Type I Interferon ◽  
Innate Immune ◽  
Type I ◽  
Potential Drug Target ◽  
Chimeric Mice

ABSTRACT Innate immune response plays a critical role in controlling invading pathogens, but such an immune response must be tightly regulated. Insufficient or overactivated immune responses may lead to harmful or even fatal consequences. To dissect the complex host-parasite interactions and the molecular mechanisms underlying innate immune responses to infections, here we investigate the role of FOS-like antigen 1 (FOSL1) in regulating the host type I interferon (IFN-I) response to malaria parasite and viral infections. FOSL1 is known as a component of a transcription factor but was recently implicated in regulating the IFN-I response to malaria parasite infection. Here we show that FOSL1 can act as a negative regulator of IFN-I signaling. Upon stimulation with poly(I:C), malaria parasite-infected red blood cells (iRBCs), or vesicular stomatitis virus (VSV), FOSL1 “translocated” from the nucleus to the cytoplasm, where it inhibited the interactions between TNF receptor-associated factor 3 (TRAF3), TIR domain-containing adapter inducing IFN-β (TRIF), and Tank-binding kinase 1 (TBK1) via impairing K63-linked polyubiquitination of TRAF3 and TRIF. Importantly, FOSL1 knockout chimeric mice had lower levels of malaria parasitemia or VSV titers in peripheral blood and decreased mortality compared with wild-type (WT) mice. Thus, our findings have identified a new role for FOSL1 in negatively regulating the host IFN-I response to malaria and viral infections and have identified a potential drug target for controlling malaria and other diseases. IMPORTANCE Infections of pathogens can trigger vigorous host immune responses, including activation and production of type I interferon (IFN-I). In this study, we investigated the role of FOSL1, a molecule previously known as a transcription factor, in negatively regulating IFN-I responses to malaria and viral infections. We showed that FOSL1 was upregulated and translocated into the cytoplasm of cells after stimulation for IFN-I production. FOSL1 could affect TRAF3 and TRIF ubiquitination and consequently impaired the association of TRAF3, TRIF, and TBK1, leading to inhibition of IFN-I signaling. In vivo experiments with FOSL1 knockout chimeric mice further validated the negative role of FOSL1 in IFN-I production and antimicrobial responses. This report reveals a new functional role for FOSL1 in IFN-I signaling and dissects the mechanism by which FOSL1 regulates IFN-I responses to malaria and viral infections, which can be explored as a potential drug target for disease control and management.

scholarly journals Dual Effect of Organogermanium Compound THGP on RIG-I-Mediated Viral Sensing and Viral Replication during Influenza a Virus Infection

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1674
Author(s):  
Sunanda Baidya ◽  
Yoko Nishimoto ◽  
Seiichi Sato ◽  
Yasuhiro Shimada ◽  
Nozomi Sakurai ◽  
...  
Keyword(s):  
Immune Responses ◽  
Influenza A ◽  
Viral Infections ◽  
Genome Replication ◽  
Type I ◽  
Innate Immune Responses ◽  
Viral Polymerase ◽  
Microbial Infections ◽  
Viral Genome Replication ◽  
Vesicular Stomatitis

The interaction of viral nucleic acid with protein factors is a crucial process for initiating viral polymerase-mediated viral genome replication while activating pattern recognition receptor (PRR)-mediated innate immune responses. It has previously been reported that a hydrolysate of Ge-132, 3-(trihydroxygermyl) propanoic acid (THGP), shows a modulatory effect on microbial infections, inflammation, and immune responses. However, the detailed mechanism by which THGP can modify these processes during viral infections remained unknown. Here, we show that THGP can specifically downregulate type I interferon (IFN) production in response to stimulation with a cytosolic RNA sensor RIG-I ligand 5′-triphosphate RNA (3pRNA) but not double-stranded RNA, DNA, or lipopolysaccharide. Consistently, treatment with THGP resulted in the dose-dependent suppression of type I IFN induction upon infections with influenza virus (IAV) and vesicular stomatitis virus, which are known to be mainly sensed by RIG-I. Mechanistically, THGP directly binds to the 5′-triphosphate moiety of viral RNA and competes with RIG-I-mediated recognition. Furthermore, we found that THGP can directly counteract the replication of IAV but not EMCV (encephalitismyocarditis virus), by inhibiting the interaction of viral polymerase with RNA genome. Finally, IAV RNA levels were significantly reduced in the lung tissues of THGP-treated mice when compared with untreated mice. These results suggest a possible therapeutic implication of THGP and show direct antiviral action, together with the suppressive activity of innate inflammation.

scholarly journals SAMHD1 suppresses innate immune responses to viral infections and inflammatory stimuli by inhibiting the NF-κB and interferon pathways

2018 ◽  
Vol 115 (16) ◽  
pp. E3798-E3807 ◽  
Author(s):  
Shuliang Chen ◽  
Serena Bonifati ◽  
Zhihua Qin ◽  
Corine St. Gelais ◽  
Karthik M. Kodigepalli ◽  
...  
Keyword(s):  
Immune Responses ◽  
Viral Infections ◽  
Inflammatory Responses ◽  
Sendai Virus ◽  
Innate Immune ◽  
Type I ◽  
Innate Immune Responses ◽  
Monocytic Cells ◽  
Intracellular Dntp ◽  
Inflammatory Stimuli

Sterile alpha motif and HD-domain–containing protein 1 (SAMHD1) blocks replication of retroviruses and certain DNA viruses by reducing the intracellular dNTP pool. SAMHD1 has been suggested to down-regulate IFN and inflammatory responses to viral infections, although the functions and mechanisms of SAMHD1 in modulating innate immunity remain unclear. Here, we show that SAMHD1 suppresses the innate immune responses to viral infections and inflammatory stimuli by inhibiting nuclear factor-κB (NF-κB) activation and type I interferon (IFN-I) induction. Compared with control cells, infection of SAMHD1-silenced human monocytic cells or primary macrophages with Sendai virus (SeV) or HIV-1, or treatment with inflammatory stimuli, induces significantly higher levels of NF-κB activation and IFN-I induction. Exogenous SAMHD1 expression in cells or SAMHD1 reconstitution in knockout cells suppresses NF-κB activation and IFN-I induction by SeV infection or inflammatory stimuli. Mechanistically, SAMHD1 inhibits NF-κB activation by interacting with NF-κB1/2 and reducing phosphorylation of the NF-κB inhibitory protein IκBα. SAMHD1 also interacts with the inhibitor-κB kinase ε (IKKε) and IFN regulatory factor 7 (IRF7), leading to the suppression of the IFN-I induction pathway by reducing IKKε-mediated IRF7 phosphorylation. Interactions of endogenous SAMHD1 with NF-κB and IFN-I pathway proteins were validated in human monocytic cells and primary macrophages. Comparing splenocytes from SAMHD1 knockout and heterozygous mice, we further confirmed SAMHD1-mediated suppression of NF-κB activation, suggesting an evolutionarily conserved property of SAMHD1. Our findings reveal functions of SAMHD1 in down-regulating innate immune responses to viral infections and inflammatory stimuli, highlighting the importance of SAMHD1 in modulating antiviral immunity.

scholarly journals Interferon α/β and Interleukin 12 Responses to Viral Infections

2002 ◽  
Vol 195 (4) ◽  
pp. 517-528 ◽  
Author(s):  
Marc Dalod ◽  
Thais P. Salazar-Mather ◽  
Lene Malmgaard ◽  
Casey Lewis ◽  
Carine Asselin-Paturel ◽  
...  
Keyword(s):  
Immune Responses ◽  
Viral Infections ◽  
Lymphocytic Choriomeningitis ◽  
Murine Cytomegalovirus ◽  
Interleukin 12 ◽  
Interferon Α ◽  
Type I ◽  
Type I Ifns ◽  
Immunocompetent Mice

Interferon (IFN)-α/β and interleukin (IL)-12 are cytokines critical in defense against viruses, but their cellular sources and mechanisms of regulation for in vivo expression remain poorly characterized. The studies presented here identified a novel subset of dendritic cells (DCs) as major producers of the cytokines during murine cytomegalovirus (MCMV) but not lymphocytic choriomeningitis virus (LCMV) infections. These DCs differed from those activated by Toxoplasma antigen but were related to plasmacytoid cells, as assessed by their CD8α+Ly6G/C+CD11b− phenotype. Another DC subset (CD8α2Ly6G/C−CD11b+) also contributed to IL-12 production in MCMV-infected immunocompetent mice, modestly. However, it dramatically increased IL-12 expression in the absence of IFN-α/β functions. Conversely, IFN-α/β production was greatly reduced under these conditions. Thus, a cross-regulation of DC subset cytokine responses was defined, whereby secretion of type I IFNs by CD8α+ DCs resulted in responses limiting IL-12 expression by CD11b+ DCs but enhancing overall IFN-α/β production. Taken together, these data indicate that CD8α+Ly6G/C+CD11b− DCs play important roles in limiting viral replication and regulating immune responses, through cytokine production, in some but not all viral infections. They also illustrate the plasticity of cellular sources for innate cytokines in vivo and provide new insights into the roles of IFNs in shaping immune responses to viruses.

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