scholarly journals USP21 negatively regulates antiviral response by acting as a RIG-I deubiquitinase

2014 ◽  
Vol 211 (2) ◽  
pp. 313-328 ◽  
Author(s):  
Yihui Fan ◽  
Renfang Mao ◽  
Yang Yu ◽  
Shangfeng Liu ◽  
Zhongcheng Shi ◽  
...  
Keyword(s):  
Rna Virus ◽  
Peritoneal Macrophages ◽  
Antiviral Response ◽  
Negative Regulation ◽  
Immune Defense ◽  
Negative Regulator ◽  
Chimeric Mice ◽  
Antiviral Responses ◽  
Bona Fide ◽  
Deficient Mice

Lys63-linked polyubiquitination of RIG-I is essential in antiviral immune defense, yet the molecular mechanism that negatively regulates this critical step is poorly understood. Here, we report that USP21 acts as a novel negative regulator in antiviral responses through its ability to bind to and deubiquitinate RIG-I. Overexpression of USP21 inhibited RNA virus–induced RIG-I polyubiquitination and RIG-I–mediated interferon (IFN) signaling, whereas deletion of USP21 resulted in elevated RIG-I polyubiquitination, IRF3 phosphorylation, IFN-α/β production, and antiviral responses in MEFs in response to RNA virus infection. USP21 also restricted antiviral responses in peritoneal macrophages (PMs) and bone marrow–derived dendritic cells (BMDCs). USP21-deficient mice spontaneously developed splenomegaly and were more resistant to VSV infection with elevated production of IFNs. Chimeric mice with USP21-deficient hematopoietic cells developed virus-induced splenomegaly and were more resistant to VSV infection. Functional comparison of three deubiquitinases (USP21, A20, and CYLD) demonstrated that USP21 acts as a bona fide RIG-I deubiquitinase to down-regulate antiviral response independent of the A20 ubiquitin-editing complex. Our studies identify a previously unrecognized role for USP21 in the negative regulation of antiviral response through deubiquitinating RIG-I.

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.

scholarly journals C4b binding protein negatively regulates TLR1/2 response

2016 ◽  
Vol 23 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Naoko Morita ◽  
Ikuko Yamai ◽  
Koichiro Takahashi ◽  
Yutaka Kusumoto ◽  
Takuma Shibata ◽  
...  
Keyword(s):  
Inflammatory Cytokine ◽  
Cytokine Production ◽  
Binding Protein ◽  
Negative Regulation ◽  
Negative Regulator ◽  
Wild Type ◽  
Inflammatory Cytokine Production ◽  
Inflammatory Signals ◽  
Deficient Mice

TLR2 associates with TLR1 and recognizes microbial lipoproteins. Pam3CSK4, a triacylated lipoprotein, is anchored to the extracellular domain of TLR1 and TLR2 and induces pro-inflammatory signals. Here we show that C4b binding protein (C4BP), which is a complement pathway inhibitor, is a TLR2-associated molecule. Immunoprecipitation assay using anti-TLR2 mAb shows that C4BP binds to TLR2. In C4BP-deficient mice, Pam3CSK4-induced IL-6 levels were increased compared with wild type mice. In C4BP-expressing cells, Pam3CSK4-induced IL-8 production was reduced depending on the C4BP expression levels. These results reveal the important role of C4BP in negative regulation of TLR1/2-dependent pro-inflammatory cytokine production. Furthermore, using a fluorescent conjugated Pam3CSK4, we show that C4BP blocks the binding of Pam3CSK4 to TLR1/2. Finally, we show that exogenous C4BP also inhibits Pam3CSK4-induced signaling leading to IL-8 production. Our results indicate C4BP binding to TLR2 and consequent neutralization of its activity otherwise inducing pro-inflammatory cytokine production. C4BP is a negative regulator of TLR1/2 activity.

scholarly journals Bcl6 Sets a Threshold for Antiviral Signaling by Restraining IRF7 Transcriptional Program

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Feng Xu ◽  
Yanhua Kang ◽  
Ningtong Zhuang ◽  
Zhe Lu ◽  
Hang Zhang ◽  
...  
Keyword(s):  
Cell Lymphoma ◽  
Rna Virus ◽  
B Cell Lymphoma ◽  
Negative Regulator ◽  
Fundamental Aspect ◽  
Antiviral Signaling ◽  
Antiviral Responses ◽  
Molecular Events ◽  
Antiviral Innate Immunity

Abstract The coordination of restraining and priming of antiviral signaling constitute a fundamental aspect of immunological functions. However, we currently know little about the molecular events that can translate the pathogenic cues into the appropriate code for antiviral defense. Our present study reports a specific role of B cell lymphoma (Bcl)6 as a checkpoint in the initiation of the host response to cytosolic RNA viruses. Remarkably, Bcl6 specifically binds to the interferon-regulatory factor (IRF)7 loci and restrains its transcription, thereby functioning as a negative regulator for interferon (IFN)-β production and antiviral responses. The signal-controlled turnover of the Bcl6, most likely mediated by microRNA-127, coordinates the antiviral response and inflammatory sequelae. Accordingly, de-repression of Bcl6 resulted in a phenotypic conversion of macrophages into highly potent IFN-producing cells and rendered mice more resistant to pathogenic RNA virus infection. The failure to remove the Bcl6 regulator, however, impedes the antiviral signaling and exaggerates viral pneumonia in mice. We thus reveal a novel key molecular checkpoint to orchestrate antiviral innate immunity.

scholarly journals HIPK2 is necessary for type I interferon–mediated antiviral immunity

2019 ◽  
Vol 12 (573) ◽  
pp. eaau4604 ◽  
Author(s):  
Lili Cao ◽  
Guang Yang ◽  
Shandian Gao ◽  
Chunxia Jing ◽  
Ruth R. Montgomery ◽  
...  
Keyword(s):  
Rna Virus ◽  
Antiviral Immunity ◽  
Type I ◽  
Wild Type ◽  
Interacting Protein ◽  
Precise Control ◽  
Antiviral Responses ◽  
Type I Ifns ◽  
Vesicular Stomatitis ◽  
Deficient Mice

Precise control of interferons (IFNs) is crucial to maintain immune homeostasis. Here, we demonstrated that homeodomain-interacting protein kinase 2 (HIPK2) was required for the production of type I IFNs in response to RNA virus infection. HIPK2 deficiency markedly impaired IFN production in macrophages after vesicular stomatitis virus (VSV) infection, and HIPK2-deficient mice were more susceptible to lethal VSV disease than were wild-type mice. After VSV infection, HIPK2 was cleaved by active caspases, which released a hyperactive, N-terminal fragment that translocated to the nucleus and further augmented antiviral responses. In part, HIPK2 interacted with ELF4 and promoted its phosphorylation at Ser369, which enabledIfn-b transcription. In addition, HIPK2 production was stimulated by type I IFNs to further enhance antiviral immunity. These data suggest that the kinase activity and nuclear localization of HIPK2 are essential for the production of type I IFNs.

scholarly journals TRAF-interacting protein (TRIP) negatively regulates IFN-β production and antiviral response by promoting proteasomal degradation of TANK-binding kinase 1

2012 ◽  
Vol 209 (10) ◽  
pp. 1703-1711 ◽  
Author(s):  
Meng Zhang ◽  
Lijuan Wang ◽  
Xueying Zhao ◽  
Kai Zhao ◽  
Hong Meng ◽  
...  
Keyword(s):  
Sendai Virus ◽  
Proteasomal Degradation ◽  
Peritoneal Macrophages ◽  
Negative Regulator ◽  
Type I ◽  
Interacting Protein ◽  
Antiviral Responses ◽  
Enhanced Expression ◽  
Vesicular Stomatitis ◽  
Irf3 Activation

TANK-binding kinase 1 (TBK1) plays an essential role in Toll-like receptor (TLR)– and retinoic acid–inducible gene I (RIG-I)–mediated induction of type I interferon (IFN; IFN-α/β) and host antiviral responses. How TBK1 activity is negatively regulated remains largely unknown. We report that TNF receptor-associated factor (TRAF)–interacting protein (TRIP) promotes proteasomal degradation of TBK1 and inhibits TLR3/4- and RIG-I–induced IFN-β signaling. TRIP knockdown resulted in augmented activation of IFN regulatory factor 3 (IRF3) and enhanced expression of IFN-β in TLR3/4- and RIG-I–activated primary peritoneal macrophages, whereas overexpression of TRIP had opposite effects. Consistently, TRIP impaired Sendai virus (SeV) infection–induced IRF3 activation and IFN-β production and promoted vesicular stomatitis virus (VSV) replication. As an E3 ubiquitin ligase, TRIP negatively regulated the cellular levels of TBK1 by directly binding to and promoting K48-linked polyubiquitination of TBK1. Therefore, we identified TRIP as a negative regulator in TLR3/4- and RIG-I–triggered antiviral responses and suggested TRIP as a potential target for the intervention of diseases with uncontrolled IFN-β production.

scholarly journals N6-methyladenosine RNA modification suppresses antiviral innate sensing pathways via reshaping double-stranded RNA

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Weinan Qiu ◽  
Qingyang Zhang ◽  
Rui Zhang ◽  
Yangxu Lu ◽  
Xin Wang ◽  
...  
Keyword(s):  
Rna Virus ◽  
Negative Regulator ◽  
Rna Modification ◽  
Type I ◽  
Viral Immunity ◽  
Potential Therapeutic Target ◽  
Viral Dsrna ◽  
Double Stranded Rna ◽  
Genetic Ablation ◽  
Vesicular Stomatitis

AbstractDouble-stranded RNA (dsRNA) is a virus-encoded signature capable of triggering intracellular Rig-like receptors (RLR) to activate antiviral signaling, but whether intercellular dsRNA structural reshaping mediated by the N6-methyladenosine (m6A) modification modulates this process remains largely unknown. Here, we show that, in response to infection by the RNA virus Vesicular Stomatitis Virus (VSV), the m6A methyltransferase METTL3 translocates into the cytoplasm to increase m6A modification on virus-derived transcripts and decrease viral dsRNA formation, thereby reducing virus-sensing efficacy by RLRs such as RIG-I and MDA5 and dampening antiviral immune signaling. Meanwhile, the genetic ablation of METTL3 in monocyte or hepatocyte causes enhanced type I IFN expression and accelerates VSV clearance. Our findings thus implicate METTL3-mediated m6A RNA modification on viral RNAs as a negative regulator for innate sensing pathways of dsRNA, and also hint METTL3 as a potential therapeutic target for the modulation of anti-viral immunity.

scholarly journals Intermittent rolling is a defect of the extravasation cascade caused by Myosin1e-deficiency in neutrophils

2019 ◽  
Vol 116 (52) ◽  
pp. 26752-26758 ◽  
Author(s):  
Eduardo Vadillo ◽  
Sandra Chánez-Paredes ◽  
Hilda Vargas-Robles ◽  
Idaira María Guerrero-Fonseca ◽  
Ramón Castellanos-Martínez ◽  
...  
Keyword(s):  
Vascular Endothelium ◽  
Actin Polymerization ◽  
Inflammatory Diseases ◽  
Chimeric Mice ◽  
Rolling Velocity ◽  
Chronic Inflammatory Diseases ◽  
Neutrophil Extravasation ◽  
Cytoskeletal Dynamics ◽  
Adhesive Interactions ◽  
Deficient Mice

Neutrophil extravasation is a migratory event in response to inflammation that depends on cytoskeletal dynamics regulated by myosins. Myosin-1e (Myo1e) is a long-tailed class-I myosin that has not yet been studied in the context of neutrophil–endothelial interactions and neutrophil extravasation. Intravital microscopy of TNFα-inflamed cremaster muscles in Myo1e-deficient mice revealed that Myo1e is required for efficient neutrophil extravasation. Specifically, Myo1e deficiency caused increased rolling velocity, decreased firm adhesion, aberrant crawling, and strongly reduced transmigration. Interestingly, we observed a striking discontinuous rolling behavior termed “intermittent rolling,” during which Myo1e-deficient neutrophils showed alternating rolling and jumping movements. Surprisingly, chimeric mice revealed that these effects were due to Myo1e deficiency in leukocytes. Vascular permeability was not significantly altered in Myo1e KO mice. Myo1e-deficient neutrophils showed diminished arrest, spreading, uropod formation, and chemotaxis due to defective actin polymerization and integrin activation. In conclusion, Myo1e critically regulates adhesive interactions of neutrophils with the vascular endothelium and neutrophil extravasation. Myo1e may therefore be an interesting target in chronic inflammatory diseases characterized by excessive neutrophil recruitment.

scholarly journals Effects of Muclin (Dmbt1) deficiency on the gastrointestinal system

2008 ◽  
Vol 294 (3) ◽  
pp. G717-G727 ◽  
Author(s):  
Robert C. De Lisle ◽  
Weihong Xu ◽  
Bruce A. Roe ◽  
Donna Ziemer
Keyword(s):  
Tumor Suppressor ◽  
Disease Severity ◽  
Exocrine Pancreas ◽  
Body Weight Gain ◽  
Exocrine Pancreatic Function ◽  
Immune Defense ◽  
Amylase Release ◽  
Releasable Pool ◽  
Significant Difference ◽  
Deficient Mice

The Dmbt1 gene encodes alternatively spliced glycoproteins that are either membrane-associated or secreted epithelial products. Functions proposed for Dmbt1 include it being a tumor suppressor, having roles in innate immune defense and inflammation, and being a Golgi-sorting receptor in the exocrine pancreas. The heavily sulfated membrane glycoprotein mucin-like glycoprotein (Muclin) is a Dmbt1 product that is strongly expressed in organs of the gastrointestinal (GI) system. To explore Muclin's functions in the GI system, the Dmbt1 gene was targeted to produce Muclin-deficient mice. Muclin-deficient mice have normal body weight gain and are fertile. The Muclin-deficient mice did not develop GI tumors, even when crossed with mice lacking the known tumor suppressor p53. When colitis was induced by dextran sulfate sodium, there was no significant difference in disease severity in Muclin-deficient mice. Also, when acute pancreatitis was induced with supraphysiological caerulein, there was no difference in disease severity in the Muclin-deficient mice. Exocrine pancreatic function was impaired, as measured by attenuated neurohormonal-stimulated amylase release from Muclin-deficient acinar cells. Also, by [35S]Met/Cys pulse-chase analysis, traffic of newly synthesized protein to the stimulus-releasable pool was significantly retarded in Muclin-deficient cells compared with wild type. Thus Muclin deficiency impairs trafficking of regulated proteins to a stimulus-releasable pool in the exocrine pancreas.

scholarly journals Genetic background-dependent abnormalities of the enteric nervous system and intestinal function in Kif26a-deficient mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yukiko Ohara ◽  
Lisa Fujimura ◽  
Akemi Sakamoto ◽  
Youichi Teratake ◽  
Shuichi Hiraoka ◽  
...  
Keyword(s):  
Genetic Background ◽  
Survival Rates ◽  
Gastrointestinal Diseases ◽  
Negative Regulator ◽  
Enteric Neurons ◽  
Enteric Neuron ◽  
Protein Coding ◽  
Underlying Mechanisms ◽  
Functional Gastrointestinal Diseases ◽  
Deficient Mice

AbstractThe Kif26a protein-coding gene has been identified as a negative regulator of the GDNF-Ret signaling pathway in enteric neurons. The aim of this study was to investigate the influence of genetic background on the phenotype of Kif26a-deficient (KO, −/−) mice. KO mice with both C57BL/6 and BALB/c genetic backgrounds were established. Survival rates and megacolon development were compared between these two strains of KO mice. Functional bowel assessments and enteric neuron histopathology were performed in the deficient mice. KO mice with the BALB/c genetic background survived more than 400 days without evidence of megacolon, while all C57BL/6 KO mice developed megacolon and died within 30 days. Local enteric neuron hyperplasia in the colon and functional bowel abnormalities were observed in BALB/c KO mice. These results indicated that megacolon and enteric neuron hyperplasia in KO mice are influenced by the genetic background. BALB/c KO mice may represent a viable model for functional gastrointestinal diseases such as chronic constipation, facilitating studies on the underlying mechanisms and providing a foundation for the development of treatments.

Sign in / Sign up

Export Citation Format

Share Document