scholarly journals The X proteins of bornaviruses interfere with type I interferon signalling

2013 ◽  
Vol 94 (2) ◽  
pp. 263-269 ◽  
Author(s):  
Jonas Johansson Wensman ◽  
Muhammad Munir ◽  
Srinivas Thaduri ◽  
Katarina Hörnaeus ◽  
Muhammad Rizwan ◽  
...  
Keyword(s):  
Type I Interferon ◽  
Rna Virus ◽  
Luciferase Reporter ◽  
Type I ◽  
Type I Ifn ◽  
X Protein ◽  
Wide Range ◽  
Reporter Assays ◽  
Interferon Signalling

Borna disease virus (BDV) is a neurotropic, negative-stranded RNA virus causing persistent infection and progressive neurological disorders in a wide range of warm-blooded animals. The role of the small non-structural X protein in viral pathogenesis is not completely understood. Here we investigated whether the X protein of BDV and avian bornavirus (ABV) interferes with the type I interferon (IFN) system, similar to other non-structural proteins of negative-stranded RNA viruses. In luciferase reporter assays, we found that the X protein of various bornaviruses interfered with the type I IFN system at all checkpoints investigated, in contrast to previously reported findings, resulting in reduced type I IFN secretion.

scholarly journals Antibodies against type-I Interferon: detection and association with severe clinical outcome in COVID-19 patients

2021 ◽  
Author(s):  
David Goncalves ◽  
Mehdi Mezidi ◽  
Paul Bastard ◽  
Magali Perret ◽  
Kahina Saker ◽  
...  
Keyword(s):  
Clinical Characteristics ◽  
Type I Interferon ◽  
Clinical Course ◽  
University Hospital ◽  
Type I ◽  
Type I Ifn ◽  
Type I Ifns ◽  
Recombinant Type ◽  
Circulating Autoantibodies

Objectives Impairment of type I interferon (IFN-I) immunity has been reported in critically ill COVID-19 patients. This defect can be explained by the presence of circulating autoantibodies against IFN-I. We set out to improve the detection and the quantification of such antibodies (Abs) in a cohort of severe Covid-19 patients, in an effort to better document the prevalence of these Abs as the pandemics evolves and how they correlate with the clinical course of the disease. Methods Anti-IFN-a Abs was investigated 84 critical COVID-19 patients who were admitted to ICU at the Lyon University Hospital, France with a commercially available kit (Thermo-Fisher). Results Twenty-one patients out of 84 (25%) had anti-IFNa2 Ab above cut-off (>34ng/mL) in sera. A neutralizing activity against IFN-a2 was evidenced in 15 of them, suggesting that 18% of patients were positive for neutralizing anti-IFN-a and -w auto-Abs. In addition, in most of patients with neutralizing IFN-I Abs, we noticed an impairment of the IFN-I response. However, we did not find any difference in terms of clinical characteristics or outcome between critical COVID-19 patients with or without neutralizing anti-IFN-a2 auto-Abs in these conditions. Finally, we detected anti-type I IFN auto-Abs in sera of COVID-19 patients were detected throughout the ICU stay. Conclusions We report that 18% of severe COVID-19 patients were positive for these Anti-Type-I IFN Abs, confirming the detrimental role of these Abs on the antiviral response. Our results further support the use of recombinant type I IFNs not targeted by the auto-Abs (e.g., IFN-b) in COVID-19 patients with an impaired IFN-I response.

scholarly journals Suppression of Type I Interferon Signaling by Flavivirus NS5

Viruses ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 712 ◽  
Author(s):  
Stephanie Thurmond ◽  
Boxiao Wang ◽  
Jikui Song ◽  
Rong Hai
Keyword(s):  
Host Defense ◽  
Type I Interferon ◽  
Mammalian Host ◽  
Type I ◽  
Signal Transducer ◽  
Type I Ifn ◽  
Interferon Signaling ◽  
Structural Protein ◽  
First Line

Type I interferon (IFN-I) is the first line of mammalian host defense against viral infection. To counteract this, the flaviviruses, like other viruses, have encoded a variety of antagonists, and use a multi-layered molecular defense strategy to establish their infections. Among the most potent antagonists is non-structural protein 5 (NS5), which has been shown for all disease-causing flaviviruses to target different steps and players of the type I IFN signaling pathway. Here, we summarize the type I IFN antagonist mechanisms used by flaviviruses with a focus on the role of NS5 in regulating one key regulator of type I IFN, signal transducer and activator of transcription 2 (STAT2).

scholarly journals FTO suppresses STAT3 activation and modulates proinflammatory interferon-stimulated gene expression

2021 ◽  
Author(s):  
Michael J McFadden ◽  
Matthew T. Sacco ◽  
Kristen A. Murphy ◽  
Moonhee Park ◽  
Nandan S. Gokhale ◽  
...  
Keyword(s):  
Gene Expression ◽  
Type 2 Diabetes ◽  
Cardiovascular Disease ◽  
Type I Interferon ◽  
Type I ◽  
Type I Ifn ◽  
Rna Modifications ◽  
Inflammatory Genes

Signaling initiated by type I interferon (IFN) results in the induction of hundreds of IFN-stimulated genes (ISGs). The type I IFN response is important for antiviral restriction, but aberrant activation of this response can lead to inflammation and autoimmunity. Regulation of this response is incompletely understood. We previously reported that the mRNA modification m6A and its deposition enzymes, METTL3 and METTL14 (METTL3/14), promote the type I IFN response by directly modifying the mRNA of a subset of ISGs to enhance their translation. Here, we determined the role of the RNA demethylase FTO in the type I IFN response. FTO, which can remove either m6A or the cap-adjacent m6Am RNA modifications, has previously been associated with obesity and body mass index, type 2 diabetes, cardiovascular disease, and inflammation. We found that FTO suppresses the transcription of a distinct set of ISGs, including many known pro-inflammatory genes, and that this regulation is not through the actions of FTO on m6Am. Further, we found that depletion of FTO led to activation of STAT3, a transcription factor that mediates responses to various cytokines, but whose role in the type I IFN response is not well understood. This activation of STAT3 increased the expression of a subset of ISGs. Importantly, this increased ISG induction resulting from FTO depletion was partially ablated by depletion of STAT3. Together, these results reveal that FTO negatively regulates STAT3-mediated signaling that induces proinflammatory ISGs during the IFN response, highlighting an important role for FTO in suppression of inflammatory genes.

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 Activation of Type I Interferon Pathway in Systemic Lupus Erythematosus: Association with Distinct Clinical Phenotypes

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Theophanis P. Karageorgas ◽  
Dimitrios D. Tseronis ◽  
Clio P. Mavragani
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Lupus Erythematosus ◽  
Type I Interferon ◽  
Clinical Manifestations ◽  
Type I ◽  
Type I Ifn ◽  
Systemic Lupus ◽  
Genetic Studies ◽  
Interferon Pathway

Growing evidence over the last few years suggests a central role of type I IFN pathway in the pathogenesis of systemic autoimmune disorders. Data from clinical and genetic studies in patients with systemic lupus erythematosus (SLE) and lupus-prone mouse models, indicates that the type I interferon system may play a pivotal role in the pathogenesis of several lupus and associated clinical features, such as nephritis, neuropsychiatric and cutaneous lupus, premature atherosclerosis as well as lupus-specific autoantibodies particularly against ribonucleoproteins. In the current paper, our aim is to summarize the latest findings supporting the association of type I IFN pathway with specific clinical manifestations in the setting of SLE providing insights on the potential use of type I IFN as a therapeutic target.

scholarly journals Disruption of Type I Interferon Signaling by the Nonstructural Protein of Severe Fever with Thrombocytopenia Syndrome Virus via the Hijacking of STAT2 and STAT1 into Inclusion Bodies

2015 ◽  
Vol 89 (8) ◽  
pp. 4227-4236 ◽  
Author(s):  
Yun-Jia Ning ◽  
Kuan Feng ◽  
Yuan-Qin Min ◽  
Wu-Chun Cao ◽  
Manli Wang ◽  
...  
Keyword(s):  
Inclusion Bodies ◽  
Viral Suppression ◽  
Type I Interferon ◽  
Nonstructural Protein ◽  
General Mechanism ◽  
Type I ◽  
Type I Ifn ◽  
Host Interactions ◽  
Severe Fever

ABSTRACTThe type I interferon (IFN) system, including IFN induction and signaling, is the critical component of the host defense line against viral infection, which, in turn, is also a vulnerable target for viral immune evasion. Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging bunyavirus. Previous data have shown that SFTSV can interfere with the early induction of type I IFNs through targeting host kinases TBK1/IKKε. In this study, we demonstrated that SFTSV also can suppress type I IFN-triggered signaling and interferon-stimulated gene (ISG) expression. Interestingly, we observed the significant inhibition of IFN signaling in cells transfected with the plasmids encoding the nonstructural protein (NSs) but not the nucleocapsid protein (NP), indicating the role of NSs as an antagonist of IFN signaling. Furthermore, coimmunoprecipitation (Co-IP) and pulldown assays indicated that NSs interacts with the cellular signal transducer and activator of transcription 2 (STAT2), and the DNA-binding domain of STAT2 may contribute to the NSs-STAT2 interaction. Combined with confocal microscopy analyses, we demonstrated that NSs sequesters STAT2 and STAT1 into viral inclusion bodies (IBs) and impairs IFN-induced STAT2 phosphorylation and nuclear translocation of both STATs, resulting in the inhibition of IFN signaling and ISG expression. SFTSV NSs-mediated hijacking of STATs in IBs represents a novel mechanism of viral suppression of IFN signaling, highlighting the role of viral IBs as the virus-built “jail” sequestering some crucial host factors and interfering with the corresponding cellular processes.IMPORTANCESFTSV is an emerging bunyavirus which can cause a severe hemorrhagic fever-like disease with high case fatality rates in humans, posing a serious health threat. However, there are no specific antivirals available, and the pathogenesis and virus-host interactions are largely unclear. Here, we demonstrated that SFTSV can inhibit type I IFN antiviral signaling by the NSs-mediated hijacking of STAT2 and STAT1 into viral IBs, highlighting the interesting role of viral IBs in virus-host interactions as the virus-built jail. Sequestering signaling molecules into IBs represents a novel and, perhaps, also a general mechanism of viral suppression of IFN signaling, the understanding of which may benefit the study of viral pathogenesis and the development of antiviral therapies.

Isoform-Selective PI3K Inhibitors for Various Diseases

2020 ◽  
Vol 20 (12) ◽  
pp. 1074-1092 ◽  
Author(s):  
Rammohan R.Y. Bheemanaboina
Keyword(s):  
Intracellular Signaling ◽  
Kinase Inhibitors ◽  
Therapeutic Potential ◽  
Type I ◽  
Selective Inhibitors ◽  
Pi3k Inhibitors ◽  
Wide Range ◽  
Lipid Kinases ◽  
Isoform Selectivity

Phosphoinositide 3-kinases (PI3Ks) are a family of ubiquitously distributed lipid kinases that control a wide variety of intracellular signaling pathways. Over the years, PI3K has emerged as an attractive target for the development of novel pharmaceuticals to treat cancer and various other diseases. In the last five years, four of the PI3K inhibitors viz. Idelalisib, Copanlisib, Duvelisib, and Alpelisib were approved by the FDA for the treatment of different types of cancer and several other PI3K inhibitors are currently under active clinical development. So far clinical candidates are non-selective kinase inhibitors with various off-target liabilities due to cross-reactivities. Hence, there is a need for the discovery of isoform-selective inhibitors with improved efficacy and fewer side-effects. The development of isoform-selective inhibitors is essential to reveal the unique functions of each isoform and its corresponding therapeutic potential. Although the clinical effect and relative benefit of pan and isoformselective inhibition will ultimately be determined, with the development of drug resistance and the demand for next-generation inhibitors, it will continue to be of great significance to understand the potential mechanism of isoform-selectivity. Because of the important role of type I PI3K family members in various pathophysiological processes, isoform-selective PI3K inhibitors may ultimately have considerable efficacy in a wide range of human diseases. This review summarizes the progress of isoformselective PI3K inhibitors in preclinical and early clinical studies for anticancer and other various diseases.

scholarly journals Role of the Innate Immunity Signaling Pathway in the Pathogenesis of Sjögren’s Syndrome

2021 ◽  
Vol 22 (6) ◽  
pp. 3090
Author(s):  
Toshimasa Shimizu ◽  
Hideki Nakamura ◽  
Atsushi Kawakami
Keyword(s):  
Immune Responses ◽  
Sjögren's Syndrome ◽  
Sjogren’S Syndrome ◽  
Sjogren's Syndrome ◽  
Innate Immune ◽  
Type I ◽  
Type I Ifn ◽  
Adaptive Immune ◽  
Sjögren‘S Syndrome

Sjögren’s syndrome (SS) is a systemic autoimmune disease characterized by chronic inflammation of the salivary and lacrimal glands and extra-glandular lesions. Adaptive immune response including T- and B-cell activation contributes to the development of SS. However, its pathogenesis has not yet been elucidated. In addition, several patients with SS present with the type I interferon (IFN) signature, which is the upregulation of the IFN-stimulated genes induced by type I IFN. Thus, innate immune responses including type I IFN activity are associated with SS pathogenesis. Recent studies have revealed the presence of activation pattern recognition receptors (PRRs) including Toll-like receptors, RNA sensor retinoic acid-inducible gene I and melanoma differentiation-associated gene 5, and inflammasomes in infiltrating and epithelial cells of the salivary glands among patients with SS. In addition, the activation of PRRs via the downstream pathway such as the type I IFN signature and nuclear factor kappa B can directly cause organ inflammation, and it is correlated with the activation of adaptive immune responses. Therefore, this study assessed the role of the innate immune signal pathway in the development of inflammation and immune abnormalities in SS.

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.

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