scholarly journals The transcription factors TFEB and TFE3 link the FLCN-AMPK signaling axis to innate immune response and pathogen resistance

2018 ◽  
Author(s):  
Leeanna El-Houjeiri ◽  
Elite Possik ◽  
Tarika Vijayaraghavan ◽  
Mathieu Paquette ◽  
José A Martina ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immune Response ◽  
Mammalian Cells ◽  
Pathogen Resistance ◽  
Innate Immune ◽  
Negative Regulator ◽  
Energy Status ◽  
Rapid Reduction ◽  
Coupling Energy ◽  
Mtorc1 Signaling

AbstractTFEB and TFE3 are transcriptional regulators of the innate immune response, but the mechanisms regulating their activation upon pathogen infection are poorly elucidated. UsingC. elegansand mammalian models, we report that the master metabolic modulator 5’-AMP-activated protein kinase (AMPK) and its negative regulator Folliculin (FLCN) act upstream of TFEB/TFE3 in the innate immune response, independently of the mTORC1 signaling pathway. In nematodes, loss of FLCN or overexpression of AMPK conferred pathogen resistanceviaactivation of TFEB/TFE3-dependent antimicrobial genes, while ablation of total AMPK activity abolished this phenotype. Similarly, in mammalian cells, loss of FLCN or pharmacological activation of AMPK induced TFEB/TFE3-dependent pro-inflammatory cytokine expression. Importantly, a rapid reduction in cellular ATP levels in murine macrophages was observed upon lipopolysaccharide (LPS) treatment accompanied by an acute AMPK activation and TFEB nuclear localization. These results uncover an ancient, highly conserved and pharmacologically actionable mechanism coupling energy status with innate immunity.

Role of miRNA-146a in the regulation of the innate immune response and cancer

2008 ◽  
Vol 36 (6) ◽  
pp. 1211-1215 ◽  
Author(s):  
Andrew E. Williams ◽  
Mark M. Perry ◽  
Sterghios A. Moschos ◽  
Hanna M. Larner-Svensson ◽  
Mark A. Lindsay
Keyword(s):  
Immune Response ◽  
Innate Immune Response ◽  
Mammalian Cells ◽  
Mrna Translation ◽  
Nuclear Factor Κb ◽  
Causal Link ◽  
Innate Immune ◽  
Major Function ◽  
Biological Responses

In mammalian cells, miRNAs (microRNAs) are the most abundant family of small non-coding RNAs that regulate mRNA translation through the RNA interference pathway. In general, it appears that the major function of miRNAs is in development, differentiation and homoeostasis, which is indicated by studies showing aberrant miRNA expression during the development of cancer. Interestingly, changes in the expression of miR-146a have been implicated in both the development of multiple cancers and in the negative regulation of inflammation induced via the innate immune response. Furthermore, miR-146a expression is driven by the transcription factor NF-κB (nuclear factor κB), which has been implicated as an important causal link between inflammation and carcinogenesis. In the present article, we review the evidence for a role of miR-146a in innate immunity and cancer and assess whether changes in miR-146a might link these two biological responses.

scholarly journals TRAF6 and TAK1 contribute to SAMHD1-mediated negative regulation of NF-κB signaling

2020 ◽  
Author(s):  
Constanza E. Espada ◽  
Corine St. Gelais ◽  
Serena Bonifati ◽  
Victoria V. Maksimova ◽  
Michael P. Cahill ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immune Response ◽  
Transforming Growth Factor ◽  
Negative Regulation ◽  
Innate Immune ◽  
Negative Regulator ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Intracellular Dntp ◽  
Hiv 1

Sterile alpha motif and HD-domain-containing protein 1 (SAMHD1) restricts HIV-1 replication by limiting the intracellular dNTP pool. SAMHD1 also suppresses the activation of NF-κB in response to viral infections and inflammatory stimuli. However, the mechanisms by which SAMHD1 negatively regulates this pathway remain unclear. Here we show that SAMHD1-mediated suppression of NF-κB activation is modulated by two key mediators of NF-κB signaling, tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) and transforming growth factor-ß-activated kinase-1 (TAK1). We compared NF-κB activation stimulated by interleukin (IL)-1ß in monocytic THP-1 control and SAMHD1 knockout (KO) cells with and without partial TRAF6 knockdown (KD), or in cells treated with TAK1 inhibitors. Relative to control cells, IL-1ß-treated SAMHD1 KO cells showed increased phosphorylation of the inhibitor of NF-κB (IκBα), an indication of pathway activation, and elevated levels of TNF-α mRNA. Moreover, SAMHD1 KO combined with TRAF6 KD or pharmacological TAK1 inhibition reduced IκBα phosphorylation and TNF-α mRNA to the level of control cells. SAMHD1 KO cells infected with single-cycle HIV-1 showed elevated infection and TNF-α mRNA levels compared to control cells, and the effects were significantly reduced by TRAF6 KD or TAK1 inhibition. We further demonstrated that overexpressed SAMHD1 inhibited TRAF6-stimulated NF-κB reporter activity in HEK293T cells in a dose-dependent manner. SAMHD1 contains a nuclear localization signal (NLS), but an NLS-defective SAMHD1 exhibited a suppressive effect similar to the wild-type protein. Our data suggest that the TRAF6-TAK1 axis contributes to SAMHD1-mediated suppression of NF-κB activation and HIV-1 infection. Importance Cells respond to pathogen infection by activating a complex innate immune signaling pathway, which culminates in the activation of transcription factors and secretion of a family of functionally and genetically related cytokines. However, excessive immune activation may cause tissue damage and detrimental effects on the host. Therefore, in order to maintain host homeostasis, the innate immune response is tightly regulated during viral infection. We have reported SAMHD1 as a novel negative regulator of the innate immune response. Here, we provide new insights into SAMHD1-mediated negative regulation of the NF-κB pathway at the TRAF6-TAK1 checkpoint. We show that SAMHD1 inhibits TAK1 activation and TRAF6 signaling in response to proinflammatory stimuli. Interestingly, TRAF6 knockdown in SAMHD1-deficient cells significantly inhibited HIV-1 infection and activation of NF-κB induced by virus infection. Our research reveals a new negative regulatory mechanism by which SAMHD1 participates in the maintenance of cellular homeostasis during HIV-1 infection and inflammation.

Cytotoxicity of, and innate immune response to, size-controlled polypyrrole nanoparticles in mammalian cells

Biomaterials ◽  
2011 ◽  
Vol 32 (9) ◽  
pp. 2342-2350 ◽  
Author(s):  
Sojin Kim ◽  
Wan-Kyu Oh ◽  
Yoon Seon Jeong ◽  
Jin-Yong Hong ◽  
Bo-Ram Cho ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immune Response ◽  
Mammalian Cells ◽  
Innate Immune ◽  
Polypyrrole Nanoparticles ◽  
Size Controlled

scholarly journals Vaccinia virus immune evasion: mechanisms, virulence and immunogenicity

2013 ◽  
Vol 94 (11) ◽  
pp. 2367-2392 ◽  
Author(s):  
Geoffrey L. Smith ◽  
Camilla T. O. Benfield ◽  
Carlos Maluquer de Motes ◽  
Michela Mazzon ◽  
Stuart W. J. Ember ◽  
...  
Keyword(s):  
Immune Response ◽  
Vaccinia Virus ◽  
Innate Immune Response ◽  
Immune Evasion ◽  
Mammalian Cells ◽  
Innate Immune ◽  
Gene Encoding ◽  
Cytokines And Chemokines ◽  
Host Innate Immune Response ◽  
New Hosts

Virus infection of mammalian cells is sensed by pattern recognition receptors and leads to an innate immune response that restricts virus replication and induces adaptive immunity. In response, viruses have evolved many countermeasures that enable them to replicate and be transmitted to new hosts, despite the host innate immune response. Poxviruses, such as vaccinia virus (VACV), have large DNA genomes and encode many proteins that are dedicated to host immune evasion. Some of these proteins are secreted from the infected cell, where they bind and neutralize complement factors, interferons, cytokines and chemokines. Other VACV proteins function inside cells to inhibit apoptosis or signalling pathways that lead to the production of interferons and pro-inflammatory cytokines and chemokines. In this review, these VACV immunomodulatory proteins are described and the potential to create more immunogenic VACV strains by manipulation of the gene encoding these proteins is discussed.

scholarly journals The PB1 protein of influenza A virus inhibits the innate immune response by targeting MAVS for NBR1-mediated selective autophagic degradation

2021 ◽  
Vol 17 (2) ◽  
pp. e1009300
Author(s):  
Yan Zeng ◽  
Shuai Xu ◽  
Yanli Wei ◽  
Xuegang Zhang ◽  
Qian Wang ◽  
...  
Keyword(s):  
Immune Response ◽  
Influenza A Virus ◽  
Innate Immune Response ◽  
Influenza A ◽  
Innate Immune ◽  
Negative Regulator ◽  
Poly I:C ◽  
H7n9 Virus ◽  
Autophagic Degradation ◽  
Negative Regulatory Mechanism

Influenza A virus (IAV) has evolved various strategies to counteract the innate immune response using different viral proteins. However, the mechanism is not fully elucidated. In this study, we identified the PB1 protein of H7N9 virus as a new negative regulator of virus- or poly(I:C)-stimulated IFN induction and specifically interacted with and destabilized MAVS. A subsequent study revealed that PB1 promoted E3 ligase RNF5 to catalyze K27-linked polyubiquitination of MAVS at Lys362 and Lys461. Moreover, we found that PB1 preferentially associated with a selective autophagic receptor neighbor of BRCA1 (NBR1) that recognizes ubiquitinated MAVS and delivers it to autophagosomes for degradation. The degradation cascade mediated by PB1 facilitates H7N9 virus infection by blocking the RIG-I-MAVS-mediated innate signaling pathway. Taken together, these data uncover a negative regulatory mechanism involving the PB1-RNF5-MAVS-NBR1 axis and provide insights into an evasion strategy employed by influenza virus that involves selective autophagy and innate signaling pathways.

scholarly journals Deficiency in Translesion DNA Polymerase ζ Induces an Innate Immune Response

2020 ◽  
Author(s):  
Sara K. Martin ◽  
Junya Tomida ◽  
Richard D. Wood
Keyword(s):  
Immune Response ◽  
Dna Polymerase ◽  
Innate Immune Response ◽  
Mammalian Cells ◽  
Dna Lesions ◽  
Innate Immune ◽  
Protective Function ◽  
Interferon Stimulated Genes ◽  
Protein Levels ◽  
Genomic Stress

ABSTRACTDNA polymerase pol ζ is regarded as a specialized DNA polymerase for bypass of DNA lesions. In mammalian cells, pol ζ also contributes to genomic stability during normal DNA replication. Disruption of Rev3l (the catalytic subunit of pol ζ) is toxic to cells and mice, with increased constitutive chromosome damage, including micronuclei. As the cellular manifestations of this genomic stress have remained unexplored, we measured genome-wide transcriptional changes by RNA-seq in pol ζ-defective cells. Expression of 1117 transcripts was altered by 4-fold or more in Rev3l knockout mouse embryonic fibroblasts (MEFs), with a pattern showing an induction of an innate immune response. We validated the increased expression of known interferon-stimulated genes (ISG) at the mRNA and protein levels. We found that the cGAS-STING axis, which senses cytosolic DNA, drives ISG expression in Rev3l knockout MEFs. These results reveal a new genome protective function of pol ζ and indicate that inhibition of pol ζ may be therapeutically useful by simultaneously increasing sensitivity to genotoxins and inducing a cytotoxic innate immune response.

scholarly journals Transcriptome Profiling of the Virus-Induced Innate Immune Response in Pteropus vampyrus and Its Attenuation by Nipah Virus Interferon Antagonist Functions

2015 ◽  
Vol 89 (15) ◽  
pp. 7550-7566 ◽  
Author(s):  
Nicole B. Glennon ◽  
Omar Jabado ◽  
Michael K. Lo ◽  
Megan L. Shaw
Keyword(s):  
Immune Response ◽  
Innate Immune Response ◽  
Mammalian Cells ◽  
Nipah Virus ◽  
A549 Cells ◽  
Hendra Virus ◽  
Innate Immune ◽  
Viral Control ◽  
Content Type ◽  
Pteropus Vampyrus

ABSTRACTBats are important reservoirs for several viruses, many of which cause lethal infections in humans but have reduced pathogenicity in bats. As the innate immune response is critical for controlling viruses, the nature of this response in bats and how it may differ from that in other mammals are of great interest. Using next-generation transcriptome sequencing (mRNA-seq), we profiled the transcriptional response ofPteropus vampyrusbat kidney (PVK) cells to Newcastle disease virus (NDV), an avian paramyxovirus known to elicit a strong innate immune response in mammalian cells. ThePteropusgenus is a known reservoir of Nipah virus (NiV) and Hendra virus (HeV). Analysis of the 200 to 300 regulated genes showed that genes for interferon (IFN) and antiviral pathways are highly upregulated in NDV-infected PVK cells, including genes for beta IFN, RIG-I, MDA5, ISG15, and IRF1. NDV-infected cells also upregulated several genes not previously characterized to be antiviral, such as RND1, SERTAD1, CHAC1, and MORC3. In fact, we show that MORC3 is induced by both IFN and NDV infection in PVK cells but is not induced by either stimulus in human A549 cells. In contrast to NDV infection, HeV and NiV infection of PVK cells failed to induce these innate immune response genes. Likewise, an attenuated response was observed in PVK cells infected with recombinant NDVs expressing the NiV IFN antagonist proteins V and W. This study provides the first global profile of a robust virus-induced innate immune response in bats and indicates that henipavirus IFN antagonist mechanisms are likely active in bat cells.IMPORTANCEBats are the reservoir host for many highly pathogenic human viruses, including henipaviruses, lyssaviruses, severe acute respiratory syndrome coronavirus, and filoviruses, and many other viruses have also been isolated from bats. Viral infections are reportedly asymptomatic or heavily attenuated in bat populations. Despite their ecological importance to viral maintenance, research into their immune system and mechanisms for viral control has only recently begun. Nipah virus and Hendra virus are two paramyxoviruses associated with high mortality rates in humans and whose reservoir is thePteropusgenus of bats. Greater knowledge of the innate immune response ofP. vampyrusbats to viral infection may elucidate how bats serve as a reservoir for so many viruses.

CYLD is a crucial negative regulator of innate immune response inEscherichia colipneumonia

2008 ◽  
Vol 10 (11) ◽  
pp. 2247-2256 ◽  
Author(s):  
Jae Hyang Lim ◽  
Un-Hwan Ha ◽  
Chang-Hoon Woo ◽  
Haidong Xu ◽  
Jian-Dong Li
Keyword(s):  
Immune Response ◽  
Innate Immune Response ◽  
Innate Immune ◽  
Negative Regulator

scholarly journals Inhibition of LPS- and CpG DNA-induced TNF-α response by oxidized phospholipids

2004 ◽  
Vol 286 (4) ◽  
pp. L808-L816 ◽  
Author(s):  
Zheng Ma ◽  
Jiang Li ◽  
Lijuan Yang ◽  
Ying Mu ◽  
Wen Xie ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immune Response ◽  
Mechanisms Of Action ◽  
Innate Immune ◽  
Negative Regulator ◽  
Oxidation Products ◽  
Oxidized Phospholipids ◽  
Oxygen Intermediates ◽  
Cpg Dna ◽  
Tnf Α

Lipid oxidation is commonly seen in the innate immune response, in which reactive oxygen intermediates are generated to kill pathogenic microorganisms. Although oxidation products of phospholipids have generally been regarded to play a role in a number of chronic inflammatory processes, several studies have shown that oxidized phospholipids inhibit the LPS-induced acute proinflammatory response in cultured macrophages and endothelial cells. We report in this study that oxidized 1-palmitoyl-2-arachidonoyl- sn-glycero-3-phosphorylcholine (PAPC), but not nonoxidized PAPC, significantly inhibits the LPS-induced TNF-α response in intact mice. Oxidized PAPC also inhibits the 2′-deoxyribo(cytidine-phosphate-guanosine) (CpG) DNA-induced TNF-α response in cultured macrophages and intact mice. To elucidate the mechanisms of action, we show that oxidized PAPC, but not nonoxidized PAPC, inhibits the LPS- and CpG-induced activation of p38 MAPK and the NF-κB cascade. These results suggest a role for oxidized lipids as a negative regulator in controlling the magnitude of the innate immune response. Further studies on the mechanisms of action may lead to development of a new type of anti-inflammatory drug for treatment of acute inflammatory diseases such as sepsis.

scholarly journals SARS-CoV-2 membrane glycoprotein M antagonizes the MAVS-mediated innate antiviral response

2020 ◽  
Author(s):  
Yu-Zhi Fu ◽  
Su-Yun Wang ◽  
Zhou-Qin Zheng ◽  
Yi Huang ◽  
Wei-Wei Li ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immune Response ◽  
Adaptor Protein ◽  
Antiviral Response ◽  
Innate Immune ◽  
Negative Regulator ◽  
M Protein ◽  
High Morbidity ◽  
Membrane Glycoprotein ◽  
Innate Antiviral Response

Abstract A novel SARS-related coronavirus (SARS-CoV-2) has recently emerged as a serious pathogen that causes high morbidity and substantial mortality. However, the mechanisms by which SARS-CoV-2 evades host immunity remain poorly understood. Here, we identified SARS-CoV-2 membrane glycoprotein M as a negative regulator of the innate immune response. We found that the M protein interacted with the central adaptor protein MAVS in the innate immune response pathways. This interaction impaired MAVS aggregation and its recruitment of downstream TRAF3, TBK1, and IRF3, leading to attenuation of the innate antiviral response. Our findings reveal a mechanism by which SARS-CoV-2 evades the innate immune response and suggest that the M protein of SARS-CoV-2 is a potential target for the development of SARS-CoV-2 interventions.

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