scholarly journals Slfn2 Regulates Type I Interferon Responses by Modulating the NF-κB Pathway

2018 ◽  
Vol 38 (16) ◽  
Author(s):  
Mariafausta Fischietti ◽  
Ahmet D. Arslan ◽  
Antonella Sassano ◽  
Diana Saleiro ◽  
Beata Majchrzak-Kita ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Type I Interferon ◽  
Critical Role ◽  
Regulatory Subunit ◽  
Type I ◽  
Type I Ifn ◽  
Targeted Disruption ◽  
Antiviral Responses ◽  
Biological Responses ◽  
Interferon Responses

ABSTRACT Although members of the Slfn family have been implicated in the regulation of type I interferon (IFN) responses, the mechanisms by which they mediate their effects remain unknown. In the present study, we provide evidence that targeted disruption of the Slfn2 gene leads to increased transcription of IFN-stimulated genes (ISGs) and enhanced type I IFN-mediated antiviral responses. We demonstrate that Slfn2 interacts with protein phosphatase 6 regulatory subunit 1 (PPP6R1), leading to reduced type I IFN-induced activation of nuclear factor kappa B (NF-κB) signaling, resulting in reduced expression of ISGs. Altogether, these data suggest a novel mechanism by which Slfn2 controls ISG expression and provide evidence for a critical role for Slfn2 in the regulation of IFN-mediated biological responses.

scholarly journals Investigation of type I interferon responses in ANCA-associated vasculitis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Isabella Batten ◽  
Mark W. Robinson ◽  
Arthur White ◽  
Cathal Walsh ◽  
Barbara Fazekas ◽  
...  
Keyword(s):  
Protein Expression ◽  
Type I Interferon ◽  
Contributory Factor ◽  
Type I ◽  
Healthy Controls ◽  
Type I Ifn ◽  
Serum Samples ◽  
Anca Associated Vasculitis ◽  
Clinical Measurements ◽  
Interferon Responses

AbstractType I interferon (IFN) dysregulation is a major contributory factor in the development of several autoimmune diseases, termed type I interferonopathies, and is thought to be the pathogenic link with chronic inflammation in these conditions. Anti-neutrophil cytoplasmic antibody (ANCA)-Associated Vasculitis (AAV) is an autoimmune disease characterised by necrotising inflammation of small blood vessels. The underlying biology of AAV is not well understood, however several studies have noted abnormalities in type I IFN responses. We hypothesised that type I IFN responses are systemically dysregulated in AAV, consistent with features of a type I interferonopathy. To investigate this, we measured the expression of seven interferon regulated genes (IRGs) (ISG15, SIGLEC1, STAT1, RSAD2, IFI27, IFI44L and IFIT1) in peripheral blood samples, as well as three type I IFN regulated proteins (CXCL10, MCP-1 and CCL19) in serum samples from AAV patients, healthy controls and disease controls. We found no difference in type I IFN regulated gene or protein expression between AAV patients and healthy controls. Furthermore, IRG and IFN regulated protein expression did not correlate with clinical measurements of disease activity in AAV patients. Thus, we conclude that systemic type I IFN responses are not key drivers of AAV pathogenesis and AAV should not be considered a type I interferonopathy.

scholarly journals Pepscan Mapping of Viral Hemorrhagic Septicemia Virus Glycoprotein G Major Lineal Determinants Implicated in Triggering Host Cell Antiviral Responses Mediated by Type I Interferon

2010 ◽  
Vol 84 (14) ◽  
pp. 7140-7150 ◽  
Author(s):  
V. Chico ◽  
A. Martinez-Lopez ◽  
M. Ortega-Villaizan ◽  
A. Falco ◽  
L. Perez ◽  
...  
Keyword(s):  
Immune Responses ◽  
Protective Antigen ◽  
Type I Interferon ◽  
Viral Hemorrhagic Septicemia Virus ◽  
Type I ◽  
Type I Ifn ◽  
Viral Glycoprotein ◽  
Antiviral Responses ◽  
Viral Hemorrhagic Septicemia ◽  
Glycoprotein G

ABSTRACT Surface glycoproteins of enveloped virus are potent elicitors of type I interferon (IFN)-mediated antiviral responses in a way that may be independent of the well-studied genome-mediated route. However, the viral glycoprotein determinants responsible for initiating the IFN response remain unidentified. In this study, we have used a collection of 60 synthetic 20-mer overlapping peptides (pepscan) spanning the full length of glycoprotein G (gpG) of viral hemorrhagic septicemia virus (VHSV) to investigate what regions of this protein are implicated in triggering the type I IFN-associated immune responses. Briefly, two regions with ability to increase severalfold the basal expression level of the IFN-stimulated mx gene and to restrict the spread of virus among responder cells were mapped to amino acid residues 280 to 310 and 340 to 370 of the gpG protein of VHSV. In addition, the results obtained suggest that an interaction between VHSV gpG and integrins might trigger the host IFN-mediated antiviral response after VHSV infection. Since it is known that type I IFN plays an important role in determining/modulating the protective-antigen-specific immune responses, the identification of viral glycoprotein determinants directly implicated in the type I IFN induction might be of special interest for designing new adjuvants and/or more-efficient and cost-effective viral vaccines as well as for improving our knowledge on how to stimulate the innate immune system.

scholarly journals Experimental and natural evidence of SARS-CoV-2 infection-induced activation of type I interferon responses

2020 ◽  
Author(s):  
Arinjay Banerjee ◽  
Nader El-Sayes ◽  
Patrick Budylowski ◽  
Daniel Richard ◽  
Hassaan Maan ◽  
...  
Keyword(s):  
Airway Epithelial Cells ◽  
Type I Interferons ◽  
Virus Protein ◽  
Type I ◽  
Airway Epithelial ◽  
Type I Ifn ◽  
Antiviral Responses ◽  
Expression Studies ◽  
Interferon Responses

SUMMARYType I interferons (IFNs) are our first line of defence against a virus. Protein over-expression studies have suggested the ability of SARS-CoV-2 proteins to block IFN responses. Emerging data also suggest that timing and extent of IFN production is associated with manifestation of COVID-19 severity. In spite of progress in understanding how SARS-CoV-2 activates antiviral responses, mechanistic studies into wildtype SARS-CoV-2-mediated induction and inhibition of human type I IFN responses are lacking. Here we demonstrate that SARS-CoV-2 infection induces a mild type I IFN response in vitro and in moderate cases of COVID-19. In vitro stimulation of type I IFN expression and signaling in human airway epithelial cells is associated with activation of canonical transcriptions factors, and SARS-CoV-2 is unable to inhibit exogenous induction of these responses. Our data demonstrate that SARS-CoV-2 is not adept in blocking type I IFN responses and provide support for ongoing IFN clinical trials.

scholarly journals A type I IFN–Flt3 ligand axis augments plasmacytoid dendritic cell development from common lymphoid progenitors

2013 ◽  
Vol 210 (12) ◽  
pp. 2515-2522 ◽  
Author(s):  
Yi-Ling Chen ◽  
Ting-Ting Chen ◽  
Li-Mei Pai ◽  
Joanna Wesoly ◽  
Hans A.R. Bluyssen ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Dendritic Cell ◽  
Type I Interferon ◽  
Plasmacytoid Dendritic Cell ◽  
Critical Role ◽  
Plasmacytoid Dendritic Cells ◽  
Type I ◽  
Type I Ifn ◽  
Flt3 Ligand ◽  
Lymphoid Progenitors

During infections and inflammation, plasmacytoid dendritic cells (pDCs) are the most potent type I interferon (IFN-I)–producing cells. However, the developmental origin of pDCs and the signals dictating pDC generation remain incompletely understood. Here, we report a synergistic role for IFN-I and Flt3 ligand (FL) in pDC development from common lymphoid progenitors (CLPs). Both conventional DCs (cDCs) and pDCs were generated from CLPs in response to FL, whereas pDC generation required higher concentrations of FL and concurrent IFN-I signaling. An absence of IFN-I receptor, impairment of IFN-I signaling, or neutralization of IFN-I significantly impeded pDC development from CLPs. Furthermore, FL induced IFN-I expression in CLPs, which in turn induced Flt3 up-regulation that facilitated survival and proliferation of CLPs, as well as their differentiation into pDCs. Collectively, these results define a critical role for the FL/IFN-I/Flt3 axis in pDC differentiation from CLPs.

scholarly journals Rubicon Modulates Antiviral Type I Interferon (IFN) Signaling by Targeting IFN Regulatory Factor 3 Dimerization

2017 ◽  
Vol 91 (14) ◽  
Author(s):  
Jae-Hoon Kim ◽  
Tae-Hwan Kim ◽  
Hyun-Cheol Lee ◽  
Chamilani Nikapitiya ◽  
Md Bashir Uddin ◽  
...  
Keyword(s):  
Type I Interferon ◽  
Cellular Mechanism ◽  
Negative Regulator ◽  
Type I ◽  
Type I Ifn ◽  
Regulatory Factor ◽  
Antiviral Responses ◽  
Proinflammatory Responses ◽  
Feedback Inhibitor

ABSTRACT Rubicon is part of a Beclin-1-Vps34-containing autophagy complex. Rubicon induces antimicrobial responses upon Toll-like receptor (TLR) stimulation and functions as a feedback inhibitor to prevent unbalanced proinflammatory responses depending on dectin-1 signaling. However, the role played by Rubicon during antiviral immune responses, particularly the type I interferon (IFN) responses, remains largely unknown. Here, we report that Rubicon acts as a negative regulator for virus-triggered IFN signaling. Knockdown of Rubicon promoted type I interferon signaling and inhibited virus replication, while overexpression of Rubicon had the opposite effect. Rubicon specifically interacts with the interferon regulatory factor (IRF) association domain (IAD) of IRF3, and this interaction leads to inhibition of the dimerization of IRF3, which negatively regulates IFN-mediated antiviral response. Thus, our findings suggest the novel additional role of Rubicon as a negative regulator that inhibits the IFN signaling and cellular antiviral responses, providing a novel cellular mechanism of IRF3 inhibition. IMPORTANCE The type I IFN system is a critical innate immune response that protects organisms against virus infection. However, type I IFN signaling must be tightly regulated to avoid excessive production of IFNs. Hence, negative regulatory mechanisms for type I IFN signaling are important, and to date, several related molecules have been identified. Here, we show that Rubicon is a major negative regulator of type I IFN signaling, and unlike previous reports of cellular molecules that inhibit IRF3 activation via proteasomal degradation or dephosphorylation of IRF3, we show that Rubicon interacts with IRF3 and that ultimately this interaction leads to inhibition of the dimerization of IRF3. Thus, we identified a novel negative regulator of type I IFN signaling pathways and a novel cellular mechanism of IRF3 inhibition. The results of this study will increase our understanding of the role of negative-feedback mechanisms that regulate type I IFN signaling and maintain immune homeostasis.

scholarly journals Thogoto Virus Infection Induces Sustained Type I Interferon Responses That Depend on RIG-I-Like Helicase Signaling of Conventional Dendritic Cells

2010 ◽  
Vol 84 (23) ◽  
pp. 12344-12350 ◽  
Author(s):  
Georg Kochs ◽  
Stefanie Bauer ◽  
Carola Vogt ◽  
Theresa Frenz ◽  
Jürg Tschopp ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Host Defense ◽  
Viral Infections ◽  
Type I Interferon ◽  
Type I ◽  
Type I Ifn ◽  
Toll Like Receptor ◽  
Tlr Signaling ◽  
The Matrix ◽  
Interferon Responses

ABSTRACT Type I interferon (IFN-α/β) induction upon viral infection contributes to the early antiviral host defense and ensures survival until the onset of adaptive immunity. Many viral infections lead to an acute, transient IFN expression which peaks a few hours after infection and reverts to initial levels after 24 to 36 h. Robust IFN expression often is conferred by specialized plasmacytoid dendritic cells (pDC) and may depend on positive-feedback amplification via the type I IFN receptor (IFNAR). Here, we show that mice infected with Thogoto virus (THOV), which is an influenza virus-like orthomyxovirus transmitted by ticks, mounted sustained IFN responses that persisted up to 72 h after infection. For this purpose, we used a variant of THOV lacking its IFN-antagonistic protein ML, an elongated version of the matrix (M) protein [THOV(ΔML)]. Of note, large amounts of type I IFN were also found in the serum of mice lacking the IFNAR. Early IFN-α expression seemed to depend on Toll-like receptor (TLR) signaling, whereas prolonged IFN-α responses strictly depended on RIG-I-like helicase (RLH) signaling. Unexpectedly, THOV(ΔML)-infected bone marrow-derived pDC (BM-pDC) produced only moderate IFN levels, whereas myeloid DC (BM-mDC) showed massive IFN induction that was IPS-1-dependent, suggesting that BM-mDC are involved in the massive, sustained IFN production in THOV(ΔML)-infected animals. Thus, our data are compatible with the model that THOV(ΔML) infection is sensed in the acute phase via TLR and RLH systems, whereas at later time points only RLH signaling is responsible for the induction of sustained IFN responses.

scholarly journals Essential role of IPS-1 in innate immune responses against RNA viruses

2006 ◽  
Vol 203 (7) ◽  
pp. 1795-1803 ◽  
Author(s):  
Himanshu Kumar ◽  
Taro Kawai ◽  
Hiroki Kato ◽  
Shintaro Sato ◽  
Ken Takahashi ◽  
...  
Keyword(s):  
Rna Viruses ◽  
Rna Virus ◽  
Critical Role ◽  
Nuclear Factor Κb ◽  
Type I ◽  
Innate Immune Responses ◽  
Antiviral Responses ◽  
Deficient Mice

IFN-β promoter stimulator (IPS)-1 was recently identified as an adapter for retinoic acid–inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (Mda5), which recognize distinct RNA viruses. Here we show the critical role of IPS-1 in antiviral responses in vivo. IPS-1–deficient mice showed severe defects in both RIG-I– and Mda5-mediated induction of type I interferon and inflammatory cytokines and were susceptible to RNA virus infection. RNA virus–induced interferon regulatory factor-3 and nuclear factor κB activation was also impaired in IPS-1–deficient cells. IPS-1, however, was not essential for the responses to either DNA virus or double-stranded B-DNA. Thus, IPS-1 is the sole adapter in both RIG-I and Mda5 signaling that mediates effective responses against a variety of RNA viruses.

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