1
|
Collados Rodríguez M, Maillard P, Journeaux A, Komarova AV, Najburg V, David RYS, Helynck O, Guo M, Zhong J, Baize S, Tangy F, Jacob Y, Munier-Lehmann H, Meurs EF. Novel Antiviral Molecules against Ebola Virus Infection. Int J Mol Sci 2023; 24:14791. [PMID: 37834238 PMCID: PMC10573436 DOI: 10.3390/ijms241914791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/19/2023] [Accepted: 09/22/2023] [Indexed: 10/15/2023] Open
Abstract
Infection with Ebola virus (EBOV) is responsible for hemorrhagic fever in humans with a high mortality rate. Combined efforts of prevention and therapeutic intervention are required to tackle highly variable RNA viruses, whose infections often lead to outbreaks. Here, we have screened the 2P2I3D chemical library using a nanoluciferase-based protein complementation assay (NPCA) and isolated two compounds that disrupt the interaction of the EBOV protein fragment VP35IID with the N-terminus of the dsRNA-binding proteins PKR and PACT, involved in IFN response and/or intrinsic immunity, respectively. The two compounds inhibited EBOV infection in cell culture as well as infection by measles virus (MV) independently of IFN induction. Consequently, we propose that the compounds are antiviral by restoring intrinsic immunity driven by PACT. Given that PACT is highly conserved across mammals, our data support further testing of the compounds in other species, as well as against other negative-sense RNA viruses.
Collapse
Affiliation(s)
- Mila Collados Rodríguez
- School of Infection & Immunity (SII), College of Medical, Veterinary and Life Sciences (MVLS), Sir Michael Stoker Building, MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow G61 1QH, UK
- Unité Hépacivirus et Immunité Innée, CNRS, UMR 3569, Département de Virologie, Institut Pasteur, 75015 Paris, France; (P.M.); (E.F.M.)
| | - Patrick Maillard
- Unité Hépacivirus et Immunité Innée, CNRS, UMR 3569, Département de Virologie, Institut Pasteur, 75015 Paris, France; (P.M.); (E.F.M.)
| | - Alexandra Journeaux
- Unit of Biology of Emerging Viral Infections, Institut Pasteur, 69007 Lyon, France; (A.J.); (S.B.)
| | - Anastassia V. Komarova
- Interactomics, RNA and Immunity Laboratory, Institut Pasteur, 75015 Paris, France;
- Unité de Génomique Virale et Vaccination, Institut Pasteur, 75015 Paris, France; (V.N.); (R.-Y.S.D.); (F.T.)
- Université Paris Cité, 75013 Paris, France;
| | - Valérie Najburg
- Unité de Génomique Virale et Vaccination, Institut Pasteur, 75015 Paris, France; (V.N.); (R.-Y.S.D.); (F.T.)
- Université Paris Cité, 75013 Paris, France;
| | - Raul-Yusef Sanchez David
- Unité de Génomique Virale et Vaccination, Institut Pasteur, 75015 Paris, France; (V.N.); (R.-Y.S.D.); (F.T.)
- Blizard Institute—Faculty of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
| | - Olivier Helynck
- Unité de Chimie et Biocatalyse, CNRS, UMR 3523, Institut Pasteur, Université de Paris, 75015 Paris, France; (O.H.); (H.M.-L.)
| | - Mingzhe Guo
- CAS Key Laboratory of Molecular Virology and Immunology, Unit of Viral Hepatitis, Shanghai Institute of Immunity and Infection, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Shanghai 200023, China; (M.G.); (J.Z.)
| | - Jin Zhong
- CAS Key Laboratory of Molecular Virology and Immunology, Unit of Viral Hepatitis, Shanghai Institute of Immunity and Infection, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Shanghai 200023, China; (M.G.); (J.Z.)
| | - Sylvain Baize
- Unit of Biology of Emerging Viral Infections, Institut Pasteur, 69007 Lyon, France; (A.J.); (S.B.)
| | - Frédéric Tangy
- Unité de Génomique Virale et Vaccination, Institut Pasteur, 75015 Paris, France; (V.N.); (R.-Y.S.D.); (F.T.)
- Université Paris Cité, 75013 Paris, France;
| | - Yves Jacob
- Université Paris Cité, 75013 Paris, France;
- Unité Génétique Moléculaire des Virus à ARN, CNRS, UMR 3569, Département de Virologie, Institut Pasteur, 75015 Paris, France
| | - Hélène Munier-Lehmann
- Unité de Chimie et Biocatalyse, CNRS, UMR 3523, Institut Pasteur, Université de Paris, 75015 Paris, France; (O.H.); (H.M.-L.)
| | - Eliane F. Meurs
- Unité Hépacivirus et Immunité Innée, CNRS, UMR 3569, Département de Virologie, Institut Pasteur, 75015 Paris, France; (P.M.); (E.F.M.)
| |
Collapse
|
2
|
Huang J, Yu Z, Li X, Yang M, Fang Q, Li Z, Wang C, Chen T, Cao X. E3 ligase HECTD3 promotes RNA virus replication and virus-induced inflammation via K33-linked polyubiquitination of PKR. Cell Death Dis 2023; 14:396. [PMID: 37402711 DOI: 10.1038/s41419-023-05923-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 06/17/2023] [Accepted: 06/23/2023] [Indexed: 07/06/2023]
Abstract
Uncontrolled viral replication and excessive inflammation are the main causes of death in the host infected with virus. Hence inhibition of intracellular viral replication and production of innate cytokines, which are the key strategies of hosts to fight virus infections, need to be finely tuned to eliminate viruses while avoid harmful inflammation. The E3 ligases in regulating virus replication and subsequent innate cytokines production remain to be fully characterized. Here we report that the deficiency of the E3 ubiquitin-protein ligase HECTD3 results in accelerated RNA virus clearance and reduced inflammatory response both in vitro and in vivo. Mechanistically, HECTD3 interacts with dsRNA-dependent protein kinase R (PKR) and mediates Lys33-linkage of PKR, which is the first non-proteolytic ubiquitin modification for PKR. This process disrupts the dimerization and phosphorylation of PKR and subsequent EIF2α activation, which results in the acceleration of virus replication, but promotes the formation of PKR-IKK complex and subsequent inflammatory response. The finding suggests HECTD3 is the potential therapeutic target for simultaneously restraining RNA virus replication and virus-induced inflammation once pharmacologically inhibited.
Collapse
Affiliation(s)
- Jiaying Huang
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Zhou Yu
- National Key Laboratory of Immunity and Inflammation, Suzhou Institute of Systems Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Suzhou, 215123, Jiangsu, China.
- National Key Laboratory of Immunity and Inflammation & Institute of Immunology, Navy Medical University, Shanghai, 200433, China.
| | - Xuelian Li
- National Key Laboratory of Immunity and Inflammation, Suzhou Institute of Systems Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Suzhou, 215123, Jiangsu, China
| | - Mingjin Yang
- National Key Laboratory of Immunity and Inflammation & Institute of Immunology, Navy Medical University, Shanghai, 200433, China
| | - Qian Fang
- National Key Laboratory of Immunity and Inflammation & Institute of Immunology, Navy Medical University, Shanghai, 200433, China
| | - Zheng Li
- National Key Laboratory of Immunity and Inflammation & Institute of Immunology, Navy Medical University, Shanghai, 200433, China
| | - Chunmei Wang
- National Key Laboratory of Immunity and Inflammation, Suzhou Institute of Systems Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Suzhou, 215123, Jiangsu, China
| | - Taoyong Chen
- National Key Laboratory of Immunity and Inflammation & Institute of Immunology, Navy Medical University, Shanghai, 200433, China
| | - Xuetao Cao
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, 310058, China.
- National Key Laboratory of Immunity and Inflammation, Suzhou Institute of Systems Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Suzhou, 215123, Jiangsu, China.
- National Key Laboratory of Immunity and Inflammation & Institute of Immunology, Navy Medical University, Shanghai, 200433, China.
- Institute of Immunology, College of Life Science, Nankai University, Tianjin, 300071, China.
| |
Collapse
|
3
|
Andlovic B, Heilmann G, Ninck S, Andrei SA, Centorrino F, Higuchi Y, Kato N, Brunsveld L, Arkin M, Menninger S, Choidas A, Wolf A, Klebl B, Kaschani F, Kaiser M, Eickhoff J, Ottmann C. IFNα primes cancer cells for Fusicoccin-induced cell death via 14-3-3 PPI stabilization. Cell Chem Biol 2023; 30:573-590.e6. [PMID: 37130519 DOI: 10.1016/j.chembiol.2023.04.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 02/02/2023] [Accepted: 04/06/2023] [Indexed: 05/04/2023]
Abstract
The natural product family of the fusicoccanes (FCs) has been shown to display anti-cancer activity, especially when combined with established therapeutic agents. FCs stabilize 14-3-3 protein-protein interactions (PPIs). Here, we tested combinations of a small library of FCs with interferon α (IFNα) on different cancer cell lines and report a proteomics approach to identify the specific 14-3-3 PPIs that are induced by IFNα and stabilized by FCs in OVCAR-3 cells. Among the identified 14-3-3 target proteins are THEMIS2, receptor interacting protein kinase 2 (RIPK2), EIF2AK2, and several members of the LDB1 complex. Biophysical and structural biology studies confirm these 14-3-3 PPIs as physical targets of FC stabilization, and transcriptome as well as pathway analyses suggest possible explanations for the observed synergistic effect of IFNα/FC treatment on cancer cells. This study elucidates the polypharmacological effects of FCs in cancer cells and identifies potential targets from the vast interactome of 14-3-3s for therapeutic intervention in oncology.
Collapse
Affiliation(s)
- Blaž Andlovic
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, the Netherlands; Lead Discovery Center GmbH, 44227 Dortmund, Germany
| | - Geronimo Heilmann
- Chemical Biology, Center of Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 2, 45117 Essen, Germany
| | - Sabrina Ninck
- Chemical Biology, Center of Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 2, 45117 Essen, Germany
| | - Sebastian A Andrei
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, the Netherlands
| | - Federica Centorrino
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, the Netherlands
| | - Yusuke Higuchi
- The Institute of Scientific and Industrial Research, Osaka University, Osaka, Ibaraki, Japan
| | - Nobuo Kato
- The Institute of Scientific and Industrial Research, Osaka University, Osaka, Ibaraki, Japan
| | - Luc Brunsveld
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, the Netherlands
| | - Michelle Arkin
- Small Molecule Discovery Center and Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94143, USA
| | | | - Axel Choidas
- Lead Discovery Center GmbH, 44227 Dortmund, Germany
| | | | - Bert Klebl
- Lead Discovery Center GmbH, 44227 Dortmund, Germany
| | - Farnusch Kaschani
- Chemical Biology, Center of Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 2, 45117 Essen, Germany
| | - Markus Kaiser
- Chemical Biology, Center of Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 2, 45117 Essen, Germany
| | - Jan Eickhoff
- Lead Discovery Center GmbH, 44227 Dortmund, Germany
| | - Christian Ottmann
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, the Netherlands.
| |
Collapse
|
4
|
Chen S, Harris M. NS5A domain I antagonises PKR to facilitate the assembly of infectious hepatitis C virus particles. PLoS Pathog 2023; 19:e1010812. [PMID: 36795772 PMCID: PMC9977016 DOI: 10.1371/journal.ppat.1010812] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 03/01/2023] [Accepted: 02/02/2023] [Indexed: 02/17/2023] Open
Abstract
Hepatitis C virus NS5A is a multifunctional phosphoprotein comprised of three domains (DI, DII and DIII). DI and DII have been shown to function in genome replication, whereas DIII has a role in virus assembly. We previously demonstrated that DI in genotype 2a (JFH1) also plays a role in virus assembly, exemplified by the P145A mutant which blocked infectious virus production. Here we extend this analysis to identify two other conserved and surface exposed residues proximal to P145 (C142 and E191) that exhibited no defect in genome replication but impaired virus production. Further analysis revealed changes in the abundance of dsRNA, the size and distribution of lipid droplets (LD) and the co-localisation between NS5A and LDs in cells infected with these mutants, compared to wildtype. In parallel, to investigate the mechanism(s) underpinning this role of DI, we assessed the involvement of the interferon-induced double-stranded RNA-dependent protein kinase (PKR). In PKR-silenced cells, C142A and E191A exhibited levels of infectious virus production, LD size and co-localisation between NS5A and LD that were indistinguishable from wildtype. Co-immunoprecipitation and in vitro pulldown experiments confirmed that wildtype NS5A domain I (but not C142A or E191A) interacted with PKR. We further showed that the assembly phenotype of C142A and E191A was restored by ablation of interferon regulatory factor-1 (IRF1), a downstream effector of PKR. These data suggest a novel interaction between NS5A DI and PKR that functions to evade an antiviral pathway that blocks virus assembly through IRF1.
Collapse
Affiliation(s)
- Shucheng Chen
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Mark Harris
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
- * E-mail:
| |
Collapse
|
5
|
Carvajal P, Bahamondes V, Jara D, Castro I, Matus S, Aguilera S, Molina C, González S, Hermoso M, Barrera MJ, González MJ. The integrated stress response is activated in the salivary glands of Sjögren's syndrome patients. Front Med (Lausanne) 2023; 10:1118703. [PMID: 37035319 PMCID: PMC10079080 DOI: 10.3389/fmed.2023.1118703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/08/2023] [Indexed: 04/11/2023] Open
Abstract
Introduction Primary Sjögren's syndrome (SS) is an autoimmune exocrinopathy that affects the structure and function of salivary and lachrymal glands. Labial salivary gland (LSG) acinar cells from SS patients lose cellular homeostasis and experience endoplasmic reticulum and oxidative stress. The integrated cellular stress response (ISR) is an adaptive pathway essential for restoring homeostasis against various stress-inducing factors, including pro-inflammatory cytokines, and endoplasmic reticulum and oxidative stress. ISR activation leads eIF2α phosphorylation, which transiently blocks protein synthesis while allowing the ATF4 expression, which induces a gene expression program that seeks to optimize cellular recovery. PKR, HRI, GCN2, and PERK are the four sentinel stress kinases that control eIF2α phosphorylation. Dysregulation and chronic activation of ISR signaling have pathologic consequences associated with inflammation. Methods Here, we analyzed the activation of the ISR in LSGs of SS-patients and non-SS sicca controls, determining the mRNA, protein, and phosphorylated-protein levels of key ISR components, as well as the expression of some of ATF4 targets. Moreover, we performed a qualitative characterization of the distribution of ISR components in LSGs from both groups and evaluated if their levels correlate with clinical parameters. Results We observed that the four ISR sensors are expressed in LSGs of both groups. However, only PKR and PERK showed increased expression and/or activation in LSGs from SS-patients. eIF2α and p-eIF2α protein levels significantly increased in SS-patients; meanwhile components of the PP1c complex responsible for eIF2α dephosphorylation decreased. ATF4 mRNA levels were decreased in LSGs from SS-patients along with hypermethylation of the ATF4 promoter. Despite low mRNA levels, SS-patients showed increased levels of ATF4 protein and ATF4-target genes involved in the antioxidant response. The acinar cells of SS-patients showed increased staining intensity for PKR, p-PKR, p-PERK, p-eIF2α, ATF4, xCT, CHOP, and NRF2. Autoantibodies, focus score, and ESSDAI were correlated with p-PERK/PERK ratio and ATF4 protein levels. Discussion In summary, the results showed an increased ISR activation in LSGs of SS-patients. The increased protein levels of ATF4 and ATF4-target genes involved in the redox homeostasis could be part of a rescue response against the various stressful conditions to which the LSGs of SS-patients are subjected and promote cell survival.
Collapse
Affiliation(s)
- Patricia Carvajal
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Verónica Bahamondes
- Departamento de Tecnología Médica, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Edison Biotechnology Institute, Ohio University, Athens, OH, United States
| | - Daniela Jara
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Isabel Castro
- Departamento de Tecnología Médica, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Soledad Matus
- Fundación Ciencia and Vida, Santiago, Chile
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Providencia, Santiago, Chile
| | - Sergio Aguilera
- Departamento de Reumatología, Clínica INDISA, Santiago, Chile
| | - Claudio Molina
- Facultad de Odontología y Ciencias de la Rehabilitación, Universidad San Sebastián, Bellavista, Santiago, Chile
| | - Sergio González
- Escuela de Odontología, Facultad de Medicina y Ciencias de la Salud, Universidad Mayor, Santiago, Chile
| | - Marcela Hermoso
- Programa de Inmunología, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - María-José Barrera
- Facultad de Odontología y Ciencias de la Rehabilitación, Universidad San Sebastián, Bellavista, Santiago, Chile
- María-José Barrera,
| | - María-Julieta González
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
- *Correspondence: María-Julieta González,
| |
Collapse
|
6
|
Wu B, Song M, Dong Q, Xiang G, Li J, Ma X, Wei F. UBR5 promotes tumor immune evasion through enhancing IFN-γ-induced PDL1 transcription in triple negative breast cancer. Am J Cancer Res 2022; 12:5086-5102. [PMID: 35836797 PMCID: PMC9274738 DOI: 10.7150/thno.74989] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/07/2022] [Indexed: 01/12/2023] Open
Abstract
Background: The up-regulation of PD-L1 is recognized as an adaption of cancer cells to evade immune surveillance and attack. However, the intrinsic mechanisms of the induction of PD-L1 by interferon-γ (IFN-γ) in tumor microenvironment remain incompletely characterized. Ubiquitin ligase E3 component N-recognition protein 5 (UBR5) has a critical role in tumorigenesis of triple negative breast cancer (TNBC) by triggering specific immune responses to the tumor. Dual targeting of UBR5 and PD-L1 exhibited superior therapeutic benefits in a preclinical TNBC model in short term. Methods: The regulation of UBR5 to PD-L1 upon IFN-γ stimulation was evaluated through in UBR5 deficiency, reconstitution or overexpression cell line models by quantitative PCR, immunohistochemistry and RNA-seq. The effects of PD-L1 regulation by UBR5 and double blockade of both genes were evaluated in mouse TNBC model. Luciferase reporter assay, chromatin immunoprecipitation-qPCR and bioinformatics analysis were performed to explore the transcription factors involved in the regulation of UBR5 to PD-L1. Results: E3 ubiquitin ligase UBR5 plays a key role in IFN-γ-induced PDL1 transcription in TNBC in an E3 ubiquitination activity-independent manner. RNA-seq-based transcriptomic analyses reveal that UBR5 globally affects the genes in the IFN-γ-induced signaling pathway. Through its poly adenylate binding (PABC) domain, UBR5 enhances the transactivation of PDL1 by upregulating protein kinase RNA-activated (PKR), and PKR's downstream factors including signal transducers and activators of transcription 1 (STAT1) and interferon regulatory factor 1 (IRF1). Restoration of PD-L1 expression in UBR5-deficient tumor cells recoups their malignancy in vivo, whereas CRISPR/Cas9-mediated simultaneous abrogation of UBR5 and PD-L1 expression yields synergistic therapeutic benefits than either blockade alone, with a strong impact on the tumor microenvironment. Conclusions: This study identifies a novel regulator of PDL1 transcription, elucidates the underlying molecular mechanisms and provides a strong rationale for combination cancer immunotherapies targeting UBR5 and PD-L1.
Collapse
Affiliation(s)
- Bingbing Wu
- Sheng Yushou Center of Cell Biology and Immunology, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Mei Song
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, New York
| | - Qun Dong
- Department of Bioinformatics and Biostatistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Gang Xiang
- Sheng Yushou Center of Cell Biology and Immunology, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jing Li
- Department of Bioinformatics and Biostatistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaojing Ma
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, New York.,✉ Corresponding author: Fang Wei, 800 Dongchuan Road, Minghang, Shanghai 200240, China. Phone: 86-21-34205287; Fax: 86-21-34205287; E-mail: ; Xiaojing Ma,
| | - Fang Wei
- Sheng Yushou Center of Cell Biology and Immunology, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.,✉ Corresponding author: Fang Wei, 800 Dongchuan Road, Minghang, Shanghai 200240, China. Phone: 86-21-34205287; Fax: 86-21-34205287; E-mail: ; Xiaojing Ma,
| |
Collapse
|
7
|
Mamatis JE, Pellizzari-Delano IE, Gallardo-Flores CE, Colpitts CC. Emerging Roles of Cyclophilin A in Regulating Viral Cloaking. Front Microbiol 2022; 13:828078. [PMID: 35242122 PMCID: PMC8886124 DOI: 10.3389/fmicb.2022.828078] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/26/2022] [Indexed: 12/24/2022] Open
Abstract
Cellular cyclophilins (Cyps) such as cyclophilin A (CypA) have emerged as key players at the virus-host interface. As host factors required for the replication of many unrelated viruses, including human immunodeficiency virus (HIV), hepatitis C virus (HCV) and coronaviruses (CoVs), Cyps are attractive targets for antiviral therapy. However, a clear understanding of how these viruses exploit Cyps to promote their replication has yet to be elucidated. Recent findings suggest that CypA contributes to cloaking of viral replication intermediates, an evasion strategy that prevents detection of viral nucleic acid by innate immune sensors. Furthermore, Cyps are emerging to have roles in regulation of cellular antiviral signaling pathways. Recruitment of Cyps by viral proteins may interfere with their ability to regulate these signaling factors. Consistent with disruption of viral cloaking and innate immune evasion, treatment with Cyp inhibitors such as cyclosporine A (CsA) restores antiviral innate immunity and induces expression of a subset of antiviral genes that restrict viral infection, which may help to explain the broad antiviral spectrum of CsA. In this review, we provide an overview of the roles of CypA in viral cloaking and evasion of innate immunity, focusing on the underlying mechanisms and new perspectives for antiviral therapies.
Collapse
Affiliation(s)
- John E Mamatis
- Department of Biomedical and Molecular Sciences, Faculty of Health Sciences, Queen's University, Kingston, ON, Canada
| | - Isabella E Pellizzari-Delano
- Department of Biomedical and Molecular Sciences, Faculty of Health Sciences, Queen's University, Kingston, ON, Canada
| | - Carla E Gallardo-Flores
- Department of Biomedical and Molecular Sciences, Faculty of Health Sciences, Queen's University, Kingston, ON, Canada
| | - Che C Colpitts
- Department of Biomedical and Molecular Sciences, Faculty of Health Sciences, Queen's University, Kingston, ON, Canada
| |
Collapse
|
8
|
Chukwurah E, Farabaugh KT, Guan BJ, Ramakrishnan P, Hatzoglou M. A tale of two proteins: PACT and PKR and their roles in inflammation. FEBS J 2021; 288:6365-6391. [PMID: 33387379 PMCID: PMC9248962 DOI: 10.1111/febs.15691] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/14/2020] [Accepted: 12/29/2020] [Indexed: 12/12/2022]
Abstract
Inflammation is a pathological hallmark associated with bacterial and viral infections, autoimmune diseases, genetic disorders, obesity and diabetes, as well as environmental stresses including physical and chemical trauma. Among numerous proteins regulating proinflammatory signaling, very few such as Protein kinase R (PKR), have been shown to play an all-pervading role in inflammation induced by varied stimuli. PKR was initially characterized as an interferon-inducible gene activated by viral double-stranded RNA with a role in protein translation inhibition. However, it has become increasingly clear that PKR is involved in multiple pathways that promote inflammation in response to stress activation, both dependent on and independent of its cellular protein activator of PKR (PACT). In this review, we discuss the signaling pathways that contribute to the initiation of inflammation, including Toll-like receptor, interferon, and RIG-I-like receptor signaling, as well as inflammasome activation. We go on to discuss the specific roles that PKR and PACT play in such proinflammatory signaling, as well as in metabolic syndrome- and environmental stress-induced inflammation.
Collapse
Affiliation(s)
- Evelyn Chukwurah
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106
| | - Kenneth T. Farabaugh
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106
| | - Bo-Jhih Guan
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106
| | | | - Maria Hatzoglou
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106
| |
Collapse
|
9
|
Kehrer T, García-Sastre A, Miorin L. Control of Innate Immune Activation by Severe Acute Respiratory Syndrome Coronavirus 2 and Other Coronaviruses. J Interferon Cytokine Res 2021; 41:205-219. [PMID: 34161170 PMCID: PMC8336211 DOI: 10.1089/jir.2021.0060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 05/07/2021] [Indexed: 12/25/2022] Open
Abstract
The ongoing coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), represents a public health crisis of unprecedented proportions. After the emergence of SARS-CoV-1 in 2002, and Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012, this is the third outbreak of a highly pathogenic zoonotic coronavirus (CoV) that the world has witnessed in the last 2 decades. Infection with highly pathogenic human CoVs often results in a severe respiratory disease characterized by a delayed and blunted interferon (IFN) response, accompanied by an excessive production of proinflammatory cytokines. This indicates that CoVs developed effective mechanisms to overcome the host innate immune response and promote viral replication and pathogenesis. In this review, we describe the key innate immune signaling pathways that are activated during infection with SARS-CoV-2 and other well studied pathogenic CoVs. In addition, we summarize the main strategies that these viruses employ to modulate the host immune responses through the antagonism of IFN induction and effector pathways.
Collapse
Affiliation(s)
- Thomas Kehrer
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Global Health Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Global Health Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Lisa Miorin
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Global Health Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| |
Collapse
|
10
|
Beauclair G, Streicher F, Chazal M, Bruni D, Lesage S, Gracias S, Bourgeau S, Sinigaglia L, Fujita T, Meurs EF, Tangy F, Jouvenet N. Retinoic Acid Inducible Gene I and Protein Kinase R, but Not Stress Granules, Mediate the Proinflammatory Response to Yellow Fever Virus. J Virol 2020; 94:e00403-20. [PMID: 32878892 PMCID: PMC7592215 DOI: 10.1128/jvi.00403-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 08/27/2020] [Indexed: 12/21/2022] Open
Abstract
Yellow fever virus (YFV) is an RNA virus primarily targeting the liver. Severe YF cases are responsible for hemorrhagic fever, plausibly precipitated by excessive proinflammatory cytokine response. Pathogen recognition receptors (PRRs), such as the cytoplasmic retinoic acid inducible gene I (RIG-I)-like receptors (RLRs), and the viral RNA sensor protein kinase R (PKR), are known to initiate a proinflammatory response upon recognition of viral genomes. Here, we sought to reveal the main determinants responsible for the acute cytokine expression occurring in human hepatocytes following YFV infection. Using a RIG-I-defective human hepatoma cell line, we found that RIG-I largely contributes to cytokine secretion upon YFV infection. In infected RIG-I-proficient hepatoma cells, RIG-I was localized in stress granules. These granules are large aggregates of stalled translation preinitiation complexes known to concentrate RLRs and PKR and are so far recognized as hubs orchestrating RNA virus sensing. Stable knockdown of PKR in hepatoma cells revealed that PKR contributes to both stress granule formation and cytokine induction upon YFV infection. However, stress granule disruption did not affect the cytokine response to YFV infection, as assessed by small interfering RNA (siRNA)-knockdown-mediated inhibition of stress granule assembly. Finally, no viral RNA was detected in stress granules using a fluorescence in situ hybridization approach coupled with immunofluorescence. Our findings suggest that both RIG-I and PKR mediate proinflammatory cytokine induction in YFV-infected hepatocytes, in a stress granule-independent manner. Therefore, by showing the uncoupling of the cytokine response from the stress granule formation, our model challenges the current view in which stress granules are required for the mounting of the acute antiviral response.IMPORTANCE Yellow fever is a mosquito-borne acute hemorrhagic disease caused by yellow fever virus (YFV). The mechanisms responsible for its pathogenesis remain largely unknown, although increased inflammation has been linked to worsened outcome. YFV targets the liver, where it primarily infects hepatocytes. We found that two RNA-sensing proteins, RIG-I and PKR, participate in the induction of proinflammatory mediators in human hepatocytes infected with YFV. We show that YFV infection promotes the formation of cytoplasmic structures, termed stress granules, in a PKR- but not RIG-I-dependent manner. While stress granules were previously postulated to be essential platforms for immune activation, we found that they are not required for the production of proinflammatory mediators upon YFV infection. Collectively, our work uncovered molecular events triggered by the replication of YFV, which could prove instrumental in clarifying the pathogenesis of the disease, with possible repercussions for disease management.
Collapse
Affiliation(s)
| | - Felix Streicher
- Department of Virology, Institut Pasteur, UMR3569 CNRS, Paris, France
| | - Maxime Chazal
- Department of Virology, Institut Pasteur, UMR3569 CNRS, Paris, France
| | - Daniela Bruni
- Department of Virology, Institut Pasteur, UMR3569 CNRS, Paris, France
| | - Sarah Lesage
- Department of Virology, Institut Pasteur, UMR3569 CNRS, Paris, France
- Université de Paris, Paris, France
| | - Ségolène Gracias
- Department of Virology, Institut Pasteur, UMR3569 CNRS, Paris, France
| | - Salomé Bourgeau
- Department of Virology, Institut Pasteur, UMR3569 CNRS, Paris, France
| | - Laura Sinigaglia
- Department of Virology, Institut Pasteur, UMR3569 CNRS, Paris, France
| | - Takashi Fujita
- Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Eliane F Meurs
- Department of Virology, Institut Pasteur, UMR3569 CNRS, Paris, France
| | - Frédéric Tangy
- Department of Virology, Institut Pasteur, UMR3569 CNRS, Paris, France
| | - Nolwenn Jouvenet
- Department of Virology, Institut Pasteur, UMR3569 CNRS, Paris, France
| |
Collapse
|
11
|
Eiermann N, Haneke K, Sun Z, Stoecklin G, Ruggieri A. Dance with the Devil: Stress Granules and Signaling in Antiviral Responses. Viruses 2020; 12:v12090984. [PMID: 32899736 PMCID: PMC7552005 DOI: 10.3390/v12090984] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/31/2020] [Accepted: 08/31/2020] [Indexed: 02/07/2023] Open
Abstract
Cells have evolved highly specialized sentinels that detect viral infection and elicit an antiviral response. Among these, the stress-sensing protein kinase R, which is activated by double-stranded RNA, mediates suppression of the host translation machinery as a strategy to limit viral replication. Non-translating mRNAs rapidly condensate by phase separation into cytosolic stress granules, together with numerous RNA-binding proteins and components of signal transduction pathways. Growing evidence suggests that the integrated stress response, and stress granules in particular, contribute to antiviral defense. This review summarizes the current understanding of how stress and innate immune signaling act in concert to mount an effective response against virus infection, with a particular focus on the potential role of stress granules in the coordination of antiviral signaling cascades.
Collapse
Affiliation(s)
- Nina Eiermann
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Katharina Haneke
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Zhaozhi Sun
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research (CIID), University of Heidelberg, 69120 Heidelberg, Germany;
| | - Georg Stoecklin
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Alessia Ruggieri
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research (CIID), University of Heidelberg, 69120 Heidelberg, Germany;
- Correspondence:
| |
Collapse
|
12
|
Hu Z, Du H, Lin G, Han K, Cheng X, Feng Z, Mao H, Hu C. Grass carp (Ctenopharyngodon idella) PACT induces cell apoptosis and activates NF-кB via PKR. FISH & SHELLFISH IMMUNOLOGY 2020; 103:377-384. [PMID: 32454210 DOI: 10.1016/j.fsi.2020.05.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/17/2020] [Accepted: 05/12/2020] [Indexed: 06/11/2023]
Abstract
As a dsRNA-dependent and interferon-induced protein kinase, PKR is involved in antiviral immune response and apoptosis mediated by various cytokines. In mammalian cells, PKR can also be activated in the absence of dsRNA. A PKR activator, PACT (PKR activating protein), also referred to as RAX (PKR-associated protein X) plays an important role. In recent years, with the increasing recognition of fish interferon system, PKR and PACT have been gradually revealed in fish. However, the function of fish PACT is unclear. In our previous work, we suggested that grass carp (Ctenopharyngodon idella) PACT must be involved in IRF2 and ATF4-mediated stress response pathways. In the present study, we found that the expression of C. idella PACT (CiPACT) and CiPKR were significantly up-regulated under the stimulation of LPS. It indicated that CiPACT and CiPKR may play an important role in response to LPS stimulation. In addition, the response time of CiPACT to LPS is earlier than that of CiPKR. It has also shown that overexpression of CiPACT in CIK cells can significantly enhance the level of p-eIF2α, induces apoptosis and translocation of Cip65 to nucleus from cytoplasm. To further understand the mechanism, we carried out the co-immunoprecipitation assay. It proved that the interaction of CiPACT and CiPKR made the phosphorylation of CiPKR. Overexpression of CiPACT induced the down-regulation of intracellular expression of bcl-2 and up-regulation of bax. However, in CiPKR knocked-down cells the expression of bcl-2 and bax were just the opposite. Therefore, the mechanism of fish PACT induces apoptosis and activates NF-кB is dependent on PKR.
Collapse
Affiliation(s)
- Zhizhen Hu
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Hailing Du
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Gang Lin
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Kun Han
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Xining Cheng
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Zhiqing Feng
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Huiling Mao
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Chengyu Hu
- School of Life Science, Nanchang University, Nanchang, 330031, China.
| |
Collapse
|
13
|
Colpitts CC, Ridewood S, Schneiderman B, Warne J, Tabata K, Ng CF, Bartenschlager R, Selwood DL, Towers GJ. Hepatitis C virus exploits cyclophilin A to evade PKR. eLife 2020; 9:e52237. [PMID: 32539931 PMCID: PMC7297535 DOI: 10.7554/elife.52237] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 05/28/2020] [Indexed: 12/12/2022] Open
Abstract
Counteracting innate immunity is essential for successful viral replication. Host cyclophilins (Cyps) have been implicated in viral evasion of host antiviral responses, although the mechanisms are still unclear. Here, we show that hepatitis C virus (HCV) co-opts the host protein CypA to aid evasion of antiviral responses dependent on the effector protein kinase R (PKR). Pharmacological inhibition of CypA rescues PKR from antagonism by HCV NS5A, leading to activation of an interferon regulatory factor-1 (IRF1)-driven cell intrinsic antiviral program that inhibits viral replication. These findings further the understanding of the complexity of Cyp-virus interactions, provide mechanistic insight into the remarkably broad antiviral spectrum of Cyp inhibitors, and uncover novel aspects of PKR activity and regulation. Collectively, our study identifies a novel antiviral mechanism that harnesses cellular antiviral immunity to suppress viral replication.
Collapse
Affiliation(s)
- Che C Colpitts
- Department of Biomedical and Molecular Sciences, Queen’s UniversityKingstonCanada
- Division of Infection and Immunity, University College LondonLondonUnited Kingdom
| | - Sophie Ridewood
- Division of Infection and Immunity, University College LondonLondonUnited Kingdom
| | - Bethany Schneiderman
- Division of Infection and Immunity, University College LondonLondonUnited Kingdom
| | - Justin Warne
- Wolfson Institute for Biomedical Research, UCLLondonUnited Kingdom
| | - Keisuke Tabata
- Department of Infectious Diseases, Molecular Virology, Heidelberg UniversityHeidelbergGermany
| | - Caitlin F Ng
- Division of Infection and Immunity, University College LondonLondonUnited Kingdom
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, Heidelberg UniversityHeidelbergGermany
- Division Virus-Associated Carcinogenesis, German Cancer Research CenterHeidelbergGermany
- German Center for Infection Research (DZIF), Heidelberg Partner SiteHeidelbergGermany
| | - David L Selwood
- Department of Medicine, Imperial College LondonLondonUnited Kingdom
| | - Greg J Towers
- Division of Infection and Immunity, University College LondonLondonUnited Kingdom
| |
Collapse
|
14
|
Piazzi M, Bavelloni A, Faenza I, Blalock W. Glycogen synthase kinase (GSK)-3 and the double-strand RNA-dependent kinase, PKR: When two kinases for the common good turn bad. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118769. [PMID: 32512016 PMCID: PMC7273171 DOI: 10.1016/j.bbamcr.2020.118769] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/29/2020] [Accepted: 05/31/2020] [Indexed: 01/08/2023]
Abstract
Glycogen synthase kinase (GSK)-3α/β and the double-stranded RNA-dependent kinase PKR are two sentinel kinases that carry-out multiple similar yet distinct functions in both the cytosol and the nucleus. While these kinases belong to separate signal transduction cascades, they demonstrate an uncanny propensity to regulate many of the same proteins either through direct phosphorylation or by altering transcription/translation, including: c-MYC, NF-κB, p53 and TAU, as well as each another. A significant number of studies centered on the GSK3 kinases have led to the identification of the GSK3 interactome and a number of substrates, which link GSK3 activity to metabolic control, translation, RNA splicing, ribosome biogenesis, cellular division, DNA repair and stress/inflammatory signaling. Interestingly, many of these same pathways and processes are controlled by PKR, but unlike the GSK3 kinases, a clear picture of proteins interacting with PKR and a complete listing of its substrates is still missing. In this review, we take a detailed look at what is known about the PKR and GSK3 kinases, how these kinases interact to influence common cellular processes (innate immunity, alternative splicing, translation, glucose metabolism) and how aberrant activation of these kinases leads to diseases such as Alzheimer's disease (AD), diabetes mellitus (DM) and cancer. GSK3α/β and PKR are major regulators of cellular homeostasis and the response to stress/inflammation and infection. GSK3α/β and PKR interact with and/or modify many of the same proteins and affect the expression of similar genes. A balance between AKT and PKR nuclear signaling may be responsible for regulating the activation of nuclear GSK3β. GSK3α/β- and PKR-dependent signaling influence major molecular mechanisms of the cell through similar intermediates. Aberrant activation of GSK3α/β and PKR is highly involved in cancer, metabolic disorders, and neurodegenerative diseases.
Collapse
Affiliation(s)
- Manuela Piazzi
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", Consiglio Nazionale delle Ricerche (IGM-CNR), Bologna, Italy; IRCCS, Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Alberto Bavelloni
- Laboratoria di Oncologia Sperimentale, IRCCS, Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Irene Faenza
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - William Blalock
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", Consiglio Nazionale delle Ricerche (IGM-CNR), Bologna, Italy; IRCCS, Istituto Ortopedico Rizzoli, Bologna, Italy.
| |
Collapse
|
15
|
Xu X, Li M, Wu C, Li D, Jiang Z, Liu C, Cheng B, Mao H, Hu C. The Fish-Specific Protein Kinase (PKZ) Initiates Innate Immune Responses via IRF3- and ISGF3-Like Mediated Pathways. Front Immunol 2019; 10:582. [PMID: 30984174 PMCID: PMC6447671 DOI: 10.3389/fimmu.2019.00582] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 03/04/2019] [Indexed: 11/13/2022] Open
Abstract
PKZ is a fish-specific protein kinase containing Zα domains. PKZ is known to induce apoptosis through phosphorylating eukaryotic initiation factor 2α kinase (eIF2α) in the same way as double-stranded RNA-dependent protein kinase (PKR), but its exact role in detecting pathogens remains to be fully elucidated. Herein, we have found that PKZ acts as a fish-specific DNA sensor by initiating IFN expression through IRF3- or ISGF3-like mediated pathways. The expression pattern of PKZ is similar to those of innate immunity mediators stimulated by poly (dA:dT) and poly (dG:dC). DNA-PKZ interaction can enhance PKZ phosphorylation and dimerization in vitro. These findings indicate that PKZ participates in cytoplasmic DNA-mediated signaling. Subcellular localization assays have also shown that PKZ is located in the cytoplasm, which suggests that PKZ acts as a cytoplasmic PRR. Meanwhile, co-IP assays have shown that PKZ can separately interact with IRF3, STING, ZDHHC1, eIF2α, IRF9, and STAT2. Further investigations have revealed that PKZ can activate IRF3 and STAT2; and that IRF3-dependent and ISGF3-like dependent mediators are critical for PKZ-induced IFN expression. These results demonstrate that PKZ acts as a special DNA pattern-recognition receptor, and that PKZ can trigger immune responses through IRF3-mediated or ISGF3-like mediated pathways in fish.
Collapse
Affiliation(s)
- Xiaowen Xu
- College of Life Science, Nanchang University, Nanchang, China
| | - Meifeng Li
- College of Life Science, Nanchang University, Nanchang, China
| | - Chuxin Wu
- College of Life Science, Nanchang University, Nanchang, China
| | - Dongming Li
- Fuzhou Medical College, Nanchang University, Fuzhou, China
| | - Zeyin Jiang
- College of Life Science, Nanchang University, Nanchang, China
| | - Changxin Liu
- College of Life Science, Nanchang University, Nanchang, China
| | - Bo Cheng
- College of Life Science, Nanchang University, Nanchang, China
| | - Huiling Mao
- College of Life Science, Nanchang University, Nanchang, China
| | - Chengyu Hu
- College of Life Science, Nanchang University, Nanchang, China
| |
Collapse
|
16
|
Gal-Ben-Ari S, Barrera I, Ehrlich M, Rosenblum K. PKR: A Kinase to Remember. Front Mol Neurosci 2019; 11:480. [PMID: 30686999 PMCID: PMC6333748 DOI: 10.3389/fnmol.2018.00480] [Citation(s) in RCA: 166] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/10/2018] [Indexed: 12/26/2022] Open
Abstract
Aging is a major risk factor for many diseases including metabolic syndrome, cancer, inflammation, and neurodegeneration. Identifying mechanistic common denominators underlying the impact of aging is essential for our fundamental understanding of age-related diseases and the possibility to propose new ways to fight them. One can define aging biochemically as prolonged metabolic stress, the innate cellular and molecular programs responding to it, and the new stable or unstable state of equilibrium between the two. A candidate to play a role in the process is protein kinase R (PKR), first identified as a cellular protector against viral infection and today known as a major regulator of central cellular processes including mRNA translation, transcriptional control, regulation of apoptosis, and cell proliferation. Prolonged imbalance in PKR activation is both affected by biochemical and metabolic parameters and affects them in turn to create a feedforward loop. Here, we portray the central role of PKR in transferring metabolic information and regulating cellular function with a focus on cancer, inflammation, and brain function. Later, we integrate information from open data sources and discuss current knowledge and gaps in the literature about the signaling cascades upstream and downstream of PKR in different cell types and function. Finally, we summarize current major points and biological means to manipulate PKR expression and/or activation and propose PKR as a therapeutic target to shift age/metabolic-dependent undesired steady states.
Collapse
Affiliation(s)
- Shunit Gal-Ben-Ari
- Laboratory of Molecular and Cellular Mechanisms Underlying Learning and Memory, Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Iliana Barrera
- Laboratory of Molecular and Cellular Mechanisms Underlying Learning and Memory, Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Marcelo Ehrlich
- Laboratory of Intracellular Trafficking and Signaling, School of Molecular Cell Biology & Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Kobi Rosenblum
- Laboratory of Molecular and Cellular Mechanisms Underlying Learning and Memory, Sagol Department of Neurobiology, University of Haifa, Haifa, Israel.,Center for Gene Manipulation in the Brain, University of Haifa, Haifa, Israel
| |
Collapse
|
17
|
Sarkis S, Dabo S, Lise MC, Neuveut C, Meurs EF, Lacoste V, Lavergne A. A potential robust antiviral defense state in the common vampire bat: Expression, induction and molecular characterization of the three interferon-stimulated genes -OAS1, ADAR1 and PKR. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 85:95-107. [PMID: 29635006 DOI: 10.1016/j.dci.2018.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/06/2018] [Accepted: 04/06/2018] [Indexed: 06/08/2023]
Abstract
Bats are known to harbor many zoonotic viruses, some of which are pathogenic to other mammals while they seem to be harmless in bats. As the interferon (IFN) response represents the first line of defense against viral infections in mammals, it is hypothesized that activation of the IFN system is one of the mechanisms enabling bats to co-exist with viruses. We have previously reported induction of type I IFN in a cell line from the common vampire bat, Desmodus rotundus, upon polyinosinic:polycytidylic acid (poly(I:C)) stimulation. To deepen our knowledge on D. rotundus' IFN-I antiviral response, we molecularly characterized three interferon-stimulated genes (ISGs), OAS1, PKR and ADAR1, closely implicated in the IFN-I antiviral response, and tested their functionality in our cellular model. We first found that D. rotundus encoded two OAS1 paralogs, OAS1a and OAS1b, and that the functional domains of the four ISGs characterized were highly conserved with those of other mammals. Despite their significant transcription level in the absence of stimulation, the transcription of the four ISGs characterized was enhanced by poly(I:C). In addition, the transcription of OAS1a and OAS1b appears to be differentially regulated. These findings demonstrate an active ISG antiviral response in D. rotundus in which OAS1b may play an important role.
Collapse
Affiliation(s)
- Sarkis Sarkis
- Laboratoire des Interactions Virus-Hôtes, Institut Pasteur de la Guyane, Cayenne, French Guiana.
| | - Stéphanie Dabo
- Hepacivirus and Innate Immunity, Institut Pasteur, 75015 Paris, France
| | - Marie-Claude Lise
- Laboratoire des Interactions Virus-Hôtes, Institut Pasteur de la Guyane, Cayenne, French Guiana
| | - Christine Neuveut
- Hepacivirus and Innate Immunity, Institut Pasteur, 75015 Paris, France
| | - Eliane F Meurs
- Hepacivirus and Innate Immunity, Institut Pasteur, 75015 Paris, France
| | - Vincent Lacoste
- Laboratoire des Interactions Virus-Hôtes, Institut Pasteur de la Guyane, Cayenne, French Guiana
| | - Anne Lavergne
- Laboratoire des Interactions Virus-Hôtes, Institut Pasteur de la Guyane, Cayenne, French Guiana.
| |
Collapse
|
18
|
Dabo S, Maillard P, Collados Rodriguez M, Hansen MD, Mazouz S, Bigot DJ, Tible M, Janvier G, Helynck O, Cassonnet P, Jacob Y, Bellalou J, Gatignol A, Patel RC, Hugon J, Munier-Lehmann H, Meurs EF. Inhibition of the inflammatory response to stress by targeting interaction between PKR and its cellular activator PACT. Sci Rep 2017; 7:16129. [PMID: 29170442 PMCID: PMC5701060 DOI: 10.1038/s41598-017-16089-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 11/07/2017] [Indexed: 02/07/2023] Open
Abstract
PKR is a cellular kinase involved in the regulation of the integrative stress response (ISR) and pro-inflammatory pathways. Two N-terminal dsRNA Binding Domains (DRBD) are required for activation of PKR, by interaction with either dsRNA or PACT, another cellular DRBD-containing protein. A role for PKR and PACT in inflammatory processes linked to neurodegenerative diseases has been proposed and raised interest for pharmacological PKR inhibitors. However, the role of PKR in inflammation is subject to controversy. We identified the flavonoid luteolin as an inhibitor of the PKR/PACT interaction at the level of their DRBDs using high-throughput screening of chemical libraries by homogeneous time-resolved fluorescence. This was further validated using NanoLuc-Based Protein Complementation Assay. Luteolin inhibits PKR phosphorylation, the ISR and the induction of pro-inflammatory cytokines in human THP1 macrophages submitted to oxidative stress and toll-like receptor (TLR) agonist. Similarly, luteolin inhibits induction of pro-inflammatory cytokines in murine microglial macrophages. In contrast, luteolin increased activation of the inflammasome, in a PKR-independent manner. Collectively, these data delineate the importance of PKR in the inflammation process to the ISR and induction of pro-inflammatory cytokines. Pharmacological inhibitors of PKR should be used in combination with drugs targeting directly the inflammasome.
Collapse
Affiliation(s)
- Stephanie Dabo
- Unité Hepacivirus and Innate Immunity, Institut Pasteur, 75015, Paris, France.,CNRS, UMR 3569, Paris, France
| | - Patrick Maillard
- Unité Hepacivirus and Innate Immunity, Institut Pasteur, 75015, Paris, France.,CNRS, UMR 3569, Paris, France
| | - Milagros Collados Rodriguez
- Unité Hepacivirus and Innate Immunity, Institut Pasteur, 75015, Paris, France.,CNRS, UMR 3569, Paris, France
| | - Marianne Doré Hansen
- Unité Hepacivirus and Innate Immunity, Institut Pasteur, 75015, Paris, France.,CNRS, UMR 3569, Paris, France.,Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, 7006, Trondheim, Norway
| | - Sabrina Mazouz
- Unité Hepacivirus and Innate Immunity, Institut Pasteur, 75015, Paris, France.,CNRS, UMR 3569, Paris, France
| | - Donna-Joe Bigot
- Unité Hepacivirus and Innate Immunity, Institut Pasteur, 75015, Paris, France.,CNRS, UMR 3569, Paris, France
| | - Marion Tible
- Center of Cognitive Neurology, Lariboisière Hospital AP-HP University Paris Diderot, Paris, France.,Inserm, U942, Paris, France
| | - Geneviève Janvier
- Unité Hepacivirus and Innate Immunity, Institut Pasteur, 75015, Paris, France.,CNRS, UMR 3569, Paris, France
| | - Olivier Helynck
- Unité de Chimie et Biocatalyse, Institut Pasteur, 75015, Paris, France.,CNRS, UMR3523, Paris, France
| | - Patricia Cassonnet
- CNRS, UMR 3569, Paris, France.,Unité de Génétique Moléculaire des Virus à ARN, Institut Pasteur, Université Paris Diderot, Paris, France
| | - Yves Jacob
- CNRS, UMR 3569, Paris, France.,Unité de Génétique Moléculaire des Virus à ARN, Institut Pasteur, Université Paris Diderot, Paris, France
| | - Jacques Bellalou
- Plate-forme des protéines recombinantes, Institut Pasteur, 75015, CNRS UMR 3528, Paris, France
| | - Anne Gatignol
- Virus-Cell Interactions Laboratory, Lady Davis Institute for Medical Research, Department of Medicine, department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Rekha C Patel
- University of South Carolina, Department of Biological Sciences, Columbia, South Carolina, 29208, USA
| | - Jacques Hugon
- Center of Cognitive Neurology, Lariboisière Hospital AP-HP University Paris Diderot, Paris, France.,Inserm, U942, Paris, France
| | - Hélène Munier-Lehmann
- Unité de Chimie et Biocatalyse, Institut Pasteur, 75015, Paris, France.,CNRS, UMR3523, Paris, France
| | - Eliane F Meurs
- Unité Hepacivirus and Innate Immunity, Institut Pasteur, 75015, Paris, France. .,CNRS, UMR 3569, Paris, France.
| |
Collapse
|
19
|
Nichols DB, De Martini W, Cottrell J. Poxviruses Utilize Multiple Strategies to Inhibit Apoptosis. Viruses 2017; 9:v9080215. [PMID: 28786952 PMCID: PMC5580472 DOI: 10.3390/v9080215] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 07/31/2017] [Accepted: 08/02/2017] [Indexed: 12/11/2022] Open
Abstract
Cells have multiple means to induce apoptosis in response to viral infection. Poxviruses must prevent activation of cellular apoptosis to ensure successful replication. These viruses devote a substantial portion of their genome to immune evasion. Many of these immune evasion products expressed during infection antagonize cellular apoptotic pathways. Poxvirus products target multiple points in both the extrinsic and intrinsic apoptotic pathways, thereby mitigating apoptosis during infection. Interestingly, recent evidence indicates that poxviruses also hijack cellular means of eliminating apoptotic bodies as a means to spread cell to cell through a process called apoptotic mimicry. Poxviruses are the causative agent of many human and veterinary diseases. Further, there is substantial interest in developing these viruses as vectors for a variety of uses including vaccine delivery and as oncolytic viruses to treat certain human cancers. Therefore, an understanding of the molecular mechanisms through which poxviruses regulate the cellular apoptotic pathways remains a top research priority. In this review, we consider anti-apoptotic strategies of poxviruses focusing on three relevant poxvirus genera: Orthopoxvirus, Molluscipoxvirus, and Leporipoxvirus. All three genera express multiple products to inhibit both extrinsic and intrinsic apoptotic pathways with many of these products required for virulence.
Collapse
Affiliation(s)
- Daniel Brian Nichols
- Department of Biological Sciences, Seton Hall University, South Orange, NJ 07039, USA.
| | - William De Martini
- Department of Biological Sciences, Seton Hall University, South Orange, NJ 07039, USA.
| | - Jessica Cottrell
- Department of Biological Sciences, Seton Hall University, South Orange, NJ 07039, USA.
| |
Collapse
|
20
|
Wang H, Xu Q, Xu X, Hu Y, Hou Q, Zhu Y, Hu C. Ctenopharyngodon idella IKKβ interacts with PKR and IκBα. Acta Biochim Biophys Sin (Shanghai) 2017; 49:729-736. [PMID: 28673044 DOI: 10.1093/abbs/gmx065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 04/13/2017] [Indexed: 02/06/2023] Open
Abstract
Inhibitor of nuclear factor kappa-B kinase β (IKKβ) is a subunit of the IKK complex. It can activate the NF-κB pathway through phosphorylating IκB in response to a wide range of stimuli. In the present study, an IKKβ gene from grass carp (Ctenopharyngodon idella; KT282114) was cloned and identified by homologous cloning and rapid-amplification of cDNA ends (RACE) technique. The complete CiIKKβ cDNA is 3428 bp in length, with the longest open reading frame (ORF) of 2337 bp encoding a polypeptide of 778 amino acids. The deduced amino acid sequence of CiIKKβ has similar domain distribution to those of mammalian. For example, CiIKKβ consists of a serine/threonine kinase domain at the N-terminal, a basic region leucin zipper (BRLZ) domain in the middle, a homeobox associated leucin zipper (HALZ) domain and an IKKβ NEMO (NF-κB essential modulator) binding domain at the C-terminal. Phylogenetic tree analysis also showed that CiIKKβ is highly homologous to zebrafish IKKβ (DrIKKβ) and clearly distinct from the mammalian and amphibian counterparts. The expression of CiIKKβ was ubiquitously found in the liver, intestine, kidney, gill, spleen, heart, and brain tissues of grass carp and significantly up-regulated in CIK cells under the stimulation with Poly I:C and UV-inactivated grass carp hemorrhagic virus. To investigate the activation mechanism of NF-κB pathway in fish and the role of CiIKKβ in the pathway, we explored the protein interactions of protein kinase R (PKR) with IKKβ and IKKβ with IκBα by co-immunoprecipitation and GST-pull down assays. The interaction between each pair was confirmed. The results suggest that CiIKKβ may be a primary member in the activation of NF-κB pathway in fish.
Collapse
Affiliation(s)
- Haizhou Wang
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang 330031, China
- College of Materials and Chemical Engineering, Pingxiang University, Pingxiang 337055, China
| | - Qun Xu
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang 330031, China
| | - Xiaowen Xu
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang 330031, China
| | - Yousheng Hu
- Medical College, Jinggangshan University, Ji'an 343009, China
| | - Qunhao Hou
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang 330031, China
| | - Youlin Zhu
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang 330031, China
| | - Chengyu Hu
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang 330031, China
| |
Collapse
|
21
|
Chang YH, Lau KS, Kuo RL, Horng JT. dsRNA Binding Domain of PKR Is Proteolytically Released by Enterovirus A71 to Facilitate Viral Replication. Front Cell Infect Microbiol 2017; 7:284. [PMID: 28702377 PMCID: PMC5487429 DOI: 10.3389/fcimb.2017.00284] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 06/12/2017] [Indexed: 01/18/2023] Open
Abstract
Enterovirus 71 (EV-A71) causes hand, foot and mouth disease in young children and infants, but can also cause severe neurological complications or even death. The double-stranded RNA (dsRNA)-dependent protein kinase R (PKR), an interferon-induced antiviral protein, phosphorylates the regulatory α-subunit of the eukaryotic translation initiation factor 2 in response to viral infection, thereby blocking the translation of cellular and viral mRNA and promoting apoptosis. The cleavage of PKR after infection with poliovirus, a prototype enterovirus, has been reported by others, but the underlying mechanism of this cleavage and its role in viral replication remain unclear. In the present study, we show that viral 3C protease cleaves PKR at a site, Q188, which differs from the site cleaved during apoptosis, D251. In contrast to the conventional phosphorylation of PKR by dsRNA, EV-A71 3C physically interacts with PKR to mediate the phosphorylation of PKR; this effect is dependent on 3C protease activity. Overexpression of a catalytically inactive PKR mutant (K296H) accelerates viral protein accumulation and increases virus titer, whereas a K64E substitution in the dsRNA binding site abolishes this advantage. We also demonstrate that PKR cleavage mediated by EV-A71 3C protease produces a short N-terminal PKR fragment that can enhance EV-A71 replication, in terms of viral RNA, viral protein, and viral titers. We conclude that PKR is co-opted by EV-A71 via viral protease 3C-mediated proteolytic activation to facilitate viral replication.
Collapse
Affiliation(s)
- Yu-Hsiu Chang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung UniversityTaoyuan, Taiwan.,National Defense Medical Center, Institute of Preventive MedicineTaipei, Taiwan
| | - Kean Seng Lau
- Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung UniversityTaoyuan, Taiwan
| | - Rei-Lin Kuo
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung UniversityTaoyuan, Taiwan.,Molecular Infectious Disease Research Center, Chang Gung Memorial HospitalTaoyuan, Taiwan
| | - Jim-Tong Horng
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung UniversityTaoyuan, Taiwan.,Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung UniversityTaoyuan, Taiwan.,Research Center for Emerging Viral Infections, College of Medicine, Chang Gung UniversityTaoyuan, Taiwan.,Molecular Infectious Disease Research Center, Chang Gung Memorial HospitalTaoyuan, Taiwan.,Research Center for Chinese Herbal Medicine and Research Center for Food and Cosmetic Safety, College of Human Ecology, Chang Gung University of Science and TechnologyTaoyuan, Taiwan
| |
Collapse
|
22
|
The kinase activity of PKR represses inflammasome activity. Cell Res 2016; 26:367-79. [PMID: 26794869 DOI: 10.1038/cr.2016.11] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 10/24/2015] [Accepted: 11/04/2015] [Indexed: 12/16/2022] Open
Abstract
The protein kinase R (PKR) functions in the antiviral response by controlling protein translation and inflammatory cell signaling pathways. We generated a transgenic, knock-in mouse in which the endogenous PKR is expressed with a point mutation that ablates its kinase activity. This novel animal allows us to probe the kinase-dependent and -independent functions of PKR. We used this animal together with a previously generated transgenic mouse that is ablated for PKR expression to determine the role of PKR in regulating the activity of the cryopyrin inflammasome. Our data demonstrate that, in contradiction to earlier reports, PKR represses cryopyrin inflammasome activity. We demonstrate that this control is mediated through the established function of PKR to inhibit protein translation of constituents of the inflammasome to prevent initial priming during innate immune signaling. These findings identify an important role for PKR to dampen inflammation during the innate immune response and caution against the previously proposed therapeutic strategy to inhibit PKR to treat inflammation.
Collapse
|
23
|
Neuroinflammation and Aβ accumulation linked to systemic inflammation are decreased by genetic PKR down-regulation. Sci Rep 2015; 5:8489. [PMID: 25687824 DOI: 10.1038/srep08489] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 01/15/2015] [Indexed: 12/18/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder, marked by senile plaques composed of amyloid-β (Aβ) peptide, neurofibrillary tangles, neuronal loss and neuroinflammation. Previous works have suggested that systemic inflammation could contribute to neuroinflammation and enhanced Aβ cerebral concentrations. The molecular pathways leading to these events are not fully understood. PKR is a pro-apoptotic kinase that can trigger inflammation and accumulates in the brain and cerebrospinal fluid of AD patients. The goal of the present study was to assess if LPS-induced neuroinflammation and Aβ production could be altered by genetic PKR down regulation. The results show that, in the hippocampus of LPS-injected wild type mice, neuroinflammation, cytokine release and Aβ production are significantly increased and not in LPS-treated PKR knock-out mice. In addition BACE1 and activated STAT3 levels, a putative transcriptional regulator of BACE1, were not found increased in the brain of PKR knock-out mice as observed in wild type mice. Using PET imaging, the decrease of hippocampal metabolism induced by systemic LPS was not observed in LPS-treated PKR knock-out mice. Altogether, these findings demonstrate that PKR plays a major role in brain changes induced by LPS and could be a valid target to modulate neuroinflammation and Aβ production.
Collapse
|
24
|
Cachat A, Alais S, Chevalier SA, Journo C, Fusil F, Dutartre H, Boniface A, Ko NL, Gessain A, Cosset FL, Suspène R, Vartanian JP, Mahieux R. ADAR1 enhances HTLV-1 and HTLV-2 replication through inhibition of PKR activity. Retrovirology 2014; 11:93. [PMID: 25389016 PMCID: PMC4245799 DOI: 10.1186/s12977-014-0093-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 10/16/2014] [Indexed: 11/25/2022] Open
Abstract
Background The role of innate immunity in general and of type I interferon
(IFN-I) in particular in HTLV-1 pathogenesis is still a matter of debate.
ADAR1-p150 is an Interferon Stimulated Gene (ISG) induced by IFN-I that can edit
viral RNAs. We therefore investigated whether it could play the role of an
anti-HTLV factor. Results We demonstrate here that ADAR1 is also expressed in the absence of
IFN stimulation in activated primary T-lymphocytes that are the natural target of
this virus and in HTLV-1 or HTLV-2 chronically infected T-cells. ADAR1 expression
is also increased in primary lymphocytes obtained from HTLV-1 infected
individuals. We show that ADAR1 enhances HTLV-1 and HTLV-2 infection in
T-lymphocytes and that this proviral effect is independent from its editing
activity. ADAR1 expression suppresses IFN-α inhibitory effect on HTLV-1 and HTLV-2
and acts through the repression of PKR phosphorylation. Discussion This study demonstrates that two interferon stimulated genes, i.e.
PKR and ADAR1 have opposite effects on HTLV replication in
vivo. The balanced expression of those proteins could determine the
fate of the viral cycle in the course of infection. Electronic supplementary material The online version of this article (doi:10.1186/s12977-014-0093-9) contains supplementary material, which is available to authorized
users.
Collapse
Affiliation(s)
- Anne Cachat
- Equipe Oncogenèse Rétrovirale, Lyon, Cedex 07, France. .,Equipe labellisée "Ligue Nationale Contre le Cancer", Lyon, Cedex 07, France. .,Centre international de recherche en infectiologie, INSERM U1111 - CNRS UMR5308, Lyon, Cedex 07, France. .,Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364, Lyon, Cedex 07, France. .,Université Lyon 1, LabEx ECOFECT - Eco-evolutionary dynamics of infectious diseases, 69364, Lyon, Cedex 07, France.
| | - Sandrine Alais
- Equipe Oncogenèse Rétrovirale, Lyon, Cedex 07, France. .,Equipe labellisée "Ligue Nationale Contre le Cancer", Lyon, Cedex 07, France. .,Centre international de recherche en infectiologie, INSERM U1111 - CNRS UMR5308, Lyon, Cedex 07, France. .,Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364, Lyon, Cedex 07, France. .,Université Lyon 1, LabEx ECOFECT - Eco-evolutionary dynamics of infectious diseases, 69364, Lyon, Cedex 07, France.
| | - Sébastien Alain Chevalier
- Equipe Oncogenèse Rétrovirale, Lyon, Cedex 07, France. .,Equipe labellisée "Ligue Nationale Contre le Cancer", Lyon, Cedex 07, France. .,Centre international de recherche en infectiologie, INSERM U1111 - CNRS UMR5308, Lyon, Cedex 07, France. .,Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364, Lyon, Cedex 07, France. .,Université Lyon 1, LabEx ECOFECT - Eco-evolutionary dynamics of infectious diseases, 69364, Lyon, Cedex 07, France.
| | - Chloé Journo
- Equipe Oncogenèse Rétrovirale, Lyon, Cedex 07, France. .,Equipe labellisée "Ligue Nationale Contre le Cancer", Lyon, Cedex 07, France. .,Centre international de recherche en infectiologie, INSERM U1111 - CNRS UMR5308, Lyon, Cedex 07, France. .,Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364, Lyon, Cedex 07, France. .,Université Lyon 1, LabEx ECOFECT - Eco-evolutionary dynamics of infectious diseases, 69364, Lyon, Cedex 07, France.
| | - Floriane Fusil
- Centre international de recherche en infectiologie, INSERM U1111 - CNRS UMR5308, Lyon, Cedex 07, France. .,Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364, Lyon, Cedex 07, France. .,Université Lyon 1, LabEx ECOFECT - Eco-evolutionary dynamics of infectious diseases, 69364, Lyon, Cedex 07, France. .,Equipe virus enveloppés, Lyon, Cedex 07, France.
| | - Hélène Dutartre
- Equipe Oncogenèse Rétrovirale, Lyon, Cedex 07, France. .,Equipe labellisée "Ligue Nationale Contre le Cancer", Lyon, Cedex 07, France. .,Centre international de recherche en infectiologie, INSERM U1111 - CNRS UMR5308, Lyon, Cedex 07, France. .,Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364, Lyon, Cedex 07, France. .,Université Lyon 1, LabEx ECOFECT - Eco-evolutionary dynamics of infectious diseases, 69364, Lyon, Cedex 07, France.
| | - Adrien Boniface
- Equipe Oncogenèse Rétrovirale, Lyon, Cedex 07, France. .,Equipe labellisée "Ligue Nationale Contre le Cancer", Lyon, Cedex 07, France. .,Centre international de recherche en infectiologie, INSERM U1111 - CNRS UMR5308, Lyon, Cedex 07, France. .,Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364, Lyon, Cedex 07, France. .,Université Lyon 1, LabEx ECOFECT - Eco-evolutionary dynamics of infectious diseases, 69364, Lyon, Cedex 07, France. .,Biology Department, Master Biosciences, Lyon, Cedex 07, France.
| | - Nga Ling Ko
- Unité d'épidémiologie et physiopathoglogie des virus oncogènes, Institut Pasteur, Paris, 75015, France.
| | - Antoine Gessain
- Unité d'épidémiologie et physiopathoglogie des virus oncogènes, Institut Pasteur, Paris, 75015, France.
| | - François-Loïc Cosset
- Centre international de recherche en infectiologie, INSERM U1111 - CNRS UMR5308, Lyon, Cedex 07, France. .,Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364, Lyon, Cedex 07, France. .,Université Lyon 1, LabEx ECOFECT - Eco-evolutionary dynamics of infectious diseases, 69364, Lyon, Cedex 07, France. .,Equipe virus enveloppés, Lyon, Cedex 07, France.
| | - Rodolphe Suspène
- Unité de rétrovirologie moléculaire, Institut Pasteur, Paris, 75015, France.
| | | | - Renaud Mahieux
- Equipe Oncogenèse Rétrovirale, Lyon, Cedex 07, France. .,Equipe labellisée "Ligue Nationale Contre le Cancer", Lyon, Cedex 07, France. .,Centre international de recherche en infectiologie, INSERM U1111 - CNRS UMR5308, Lyon, Cedex 07, France. .,Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364, Lyon, Cedex 07, France. .,Université Lyon 1, LabEx ECOFECT - Eco-evolutionary dynamics of infectious diseases, 69364, Lyon, Cedex 07, France.
| |
Collapse
|
25
|
de la Cruz-Herrera CF, Campagna M, García MA, Marcos-Villar L, Lang V, Baz-Martínez M, Gutiérrez S, Vidal A, Rodríguez MS, Esteban M, Rivas C. Activation of the double-stranded RNA-dependent protein kinase PKR by small ubiquitin-like modifier (SUMO). J Biol Chem 2014; 289:26357-26367. [PMID: 25074923 PMCID: PMC4176227 DOI: 10.1074/jbc.m114.560961] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 07/11/2014] [Indexed: 01/07/2023] Open
Abstract
The dsRNA-dependent kinase PKR is an interferon-inducible protein with ability to phosphorylate the α subunit of the eukaryotic initiation factor (eIF)-2 complex, resulting in a shut-off of general translation, induction of apoptosis, and inhibition of virus replication. Here we analyzed the modification of PKR by the small ubiquitin-like modifiers SUMO1 and SUMO2 and evaluated the consequences of PKR SUMOylation. Our results indicate that PKR is modified by both SUMO1 and SUMO2, in vitro and in vivo. We identified lysine residues Lys-60, Lys-150, and Lys-440 as SUMOylation sites in PKR. We show that SUMO is required for efficient PKR-dsRNA binding, PKR dimerization, and eIF2α phosphorylation. Furthermore, we demonstrate that SUMO potentiates the inhibition of protein synthesis induced by PKR in response to dsRNA, whereas a PKR SUMOylation mutant is impaired in its ability to inhibit protein synthesis and shows reduced capability to control vesicular stomatitis virus replication and to induce apoptosis in response to vesicular stomatitis virus infection. In summary, our data demonstrate the important role of SUMO in processes mediated by the activation of PKR.
Collapse
Affiliation(s)
- Carlos F de la Cruz-Herrera
- Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Darwin 3, Madrid 28049
| | - Michela Campagna
- Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Darwin 3, Madrid 28049
| | - Maria A García
- Unidad de Investigación, Hospital Universitario Virgen de las Nieves, 18014 Granada
| | - Laura Marcos-Villar
- Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Darwin 3, Madrid 28049
| | - Valerie Lang
- Ubiquitylation and Cancer Molecular Biology Laboratory, Inbiomed, San Sebastian-Donostia, 20009 Gipuzkoa, Spain
| | - Maite Baz-Martínez
- Centro de Investigación en Medicina Molecular (CIMUS), Universidade de Santiago de Compostela, Instituto de Investigaciones Sanitarias (IDIS), Santiago de Compostela E15782
| | - Sylvia Gutiérrez
- Confocal Service of Centro Nacional de Biotecnología-CSIC, Darwin 3, Madrid 28049, and
| | - Anxo Vidal
- Departamento de Fisioloxía and Centro de Investigación en Medicina Molecular (CIMUS), Universidade de Santiago de Compostela, Instituto de Investigaciones Sanitarias (IDIS), Santiago de Compostela E15782, Spain
| | - Manuel S Rodríguez
- Ubiquitylation and Cancer Molecular Biology Laboratory, Inbiomed, San Sebastian-Donostia, 20009 Gipuzkoa, Spain
| | - Mariano Esteban
- Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Darwin 3, Madrid 28049
| | - Carmen Rivas
- Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Darwin 3, Madrid 28049,; Centro de Investigación en Medicina Molecular (CIMUS), Universidade de Santiago de Compostela, Instituto de Investigaciones Sanitarias (IDIS), Santiago de Compostela E15782,.
| |
Collapse
|
26
|
Feng Q, Langereis MA, van Kuppeveld FJM. Induction and suppression of innate antiviral responses by picornaviruses. Cytokine Growth Factor Rev 2014; 25:577-85. [PMID: 25086453 PMCID: PMC7172595 DOI: 10.1016/j.cytogfr.2014.07.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 07/03/2014] [Indexed: 12/24/2022]
Abstract
The family Picornaviridae comprises of small, non-enveloped, positive-strand RNA viruses and contains many human and animal pathogens including enteroviruses (e.g. poliovirus, coxsackievirus, enterovirus 71 and rhinovirus), cardioviruses (e.g. encephalomyocarditis virus), hepatitis A virus and foot-and-mouth disease virus. Picornavirus infections activate a cytosolic RNA sensor, MDA5, which in turn, induces a type I interferon response, a crucial component of antiviral immunity. Moreover, picornaviruses activate the formation of stress granules (SGs), large aggregates of preassembled mRNPs (messenger ribonucleoprotein particles) to temporarily store these molecules upon cellular stress. Meanwhile, picornaviruses actively suppress these antiviral responses to ensure efficient replication. In this review we provide an overview of the induction and suppression of the MDA5-mediated IFN-α/β response and the cellular stress pathway by picornaviruses.
Collapse
Affiliation(s)
- Qian Feng
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, University of Utrecht, 3584CL Utrecht, The Netherlands
| | - Martijn A Langereis
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, University of Utrecht, 3584CL Utrecht, The Netherlands
| | - Frank J M van Kuppeveld
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, University of Utrecht, 3584CL Utrecht, The Netherlands.
| |
Collapse
|
27
|
Clerzius G, Shaw E, Daher A, Burugu S, Gélinas JF, Ear T, Sinck L, Routy JP, Mouland AJ, Patel RC, Gatignol A. The PKR activator, PACT, becomes a PKR inhibitor during HIV-1 replication. Retrovirology 2013; 10:96. [PMID: 24020926 PMCID: PMC3848765 DOI: 10.1186/1742-4690-10-96] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 09/06/2013] [Indexed: 11/29/2022] Open
Abstract
Background HIV-1 translation is modulated by the activation of the interferon (IFN)-inducible Protein Kinase RNA-activated (PKR). PKR phosphorylates its downstream targets, including the alpha subunit of the eukaryotic translation Initiation Factor 2 (eIF2α), which decreases viral replication. The PKR Activator (PACT) is known to activate PKR after a cellular stress. In lymphocytic cell lines, HIV-1 activates PKR only transiently and not when cells replicate the virus at high levels. The regulation of this activation is due to a combination of viral and cellular factors that have been only partially identified. Results PKR is transiently induced and activated in peripheral blood mononuclear cells after HIV-1 infection. The addition of IFN reduces viral replication, and induces both the production and phosphorylation of PKR. In lymphocytic Jurkat cells infected by HIV-1, a multiprotein complex around PKR contains the double-stranded RNA binding proteins (dsRBPs), adenosine deaminase acting on RNA (ADAR)1 and PACT. In HEK 293T cells transfected with an HIV-1 molecular clone, PACT unexpectedly inhibited PKR and eIF2α phosphorylation and increased HIV-1 protein expression and virion production in the presence of either endogenous PKR alone or overexpressed PKR. The comparison between different dsRBPs showed that ADAR1, TAR RNA Binding Protein (TRBP) and PACT inhibit PKR and eIF2α phosphorylation in HIV-infected cells, whereas Staufen1 did not. Individual or a combination of short hairpin RNAs against PACT or ADAR1 decreased HIV-1 protein expression. In the astrocytic cell line U251MG, which weakly expresses TRBP, PACT mediated an increased HIV-1 protein expression and a decreased PKR phosphorylation. In these cells, a truncated PACT, which constitutively activates PKR in non-infected cells showed no activity on either PKR or HIV-1 protein expression. Finally, PACT and ADAR1 interact with each other in the absence of RNAs. Conclusion In contrast to its previously described activity, PACT contributes to PKR dephosphorylation during HIV-1 replication. This activity is in addition to its heterodimer formation with TRBP and could be due to its binding to ADAR1. HIV-1 has evolved to replicate in cells with high levels of TRBP, to induce the expression of ADAR1 and to change the function of PACT for PKR inhibition and increased replication.
Collapse
Affiliation(s)
- Guerline Clerzius
- Lady Davis Institute for Medical Research, 3999 Côte Ste Catherine, Montréal, QC H3T 1E2, Canada.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Bai H, Chen T, Ming J, Sun H, Cao P, Fusco DN, Chung RT, Chorev M, Jin Q, Aktas BH. Dual activators of protein kinase R (PKR) and protein kinase R-like kinase PERK identify common and divergent catalytic targets. Chembiochem 2013; 14:1255-62. [PMID: 23784735 PMCID: PMC3808843 DOI: 10.1002/cbic.201300177] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Indexed: 01/18/2023]
Abstract
Chemical genetics has evolved into a powerful tool for studying gene function in normal and pathobiology. PKR and PERK, two eukaryotic translation initiation factor 2 alpha (eIF2α) kinases, play critical roles in the maintenance of cellular hemostasis, metabolic stability, and anti-viral defenses. Both kinases interact with and phosphorylate additional substrates including tumor suppressor p53 and nuclear protein 90. Loss of function of both kinases has been studied by reverse genetics and with recently identified inhibitors. In contrast, no activating probes for studying the catalytic activity of these kinases are available. We identified 3-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-5,7-dihydroxy-4H-chromen-4-one (DHBDC) as a specific dual activator of PKR and PERK by screening a chemical library of 20 000 small molecules in a dual luciferase surrogate eIF2α phosphorylation assay. We present here extensive biological characterization and a preliminary structure-activity relationship of DHBDC, which phosphorylates eIF2α by activating PKR and PERK but no other eIF2α kinases. These agents also activate downstream effectors of eIF2α phosphorylation by inducing CEBP homologue protein, suppressing cyclin D1 expression, and inhibiting cancer cell proliferation, all in a manner dependent on PKR and PERK. Consistent with the role of eIF2α phosphorylation in viral infection, DHBDC inhibits the proliferation of human hepatitis C virus. Finally, DHBDC induces the phosphorylation of IκBα and activates the NF-κB pathway. Surprisingly, activation of the NF-κB pathway is dependent on PERK but independent of PKR activity. These data indicate that DHBDC is an invaluable probe for elucidating the role of PKR and PERK in normal and pathobiology.
Collapse
Affiliation(s)
- Huijun Bai
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, 6 Rong Jing Jie, Beijing 100176, China
- Hematology Laboratory for Translational Research, Department of Medicine. Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
| | - Ting Chen
- Hematology Laboratory for Translational Research, Department of Medicine. Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
| | - Jie Ming
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
| | - Hong Sun
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
- Basic Medical College, Hebei United University, Tangshan, Hebei, 063000, China
| | - Peng Cao
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
| | - Dahlene N. Fusco
- Gastrointestinal Unit, Massachusetts General Hospital Boston MA 02114
| | - Raymond T. Chung
- Gastrointestinal Unit, Massachusetts General Hospital Boston MA 02114
| | - Michael Chorev
- Hematology Laboratory for Translational Research, Department of Medicine. Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
| | - Qi Jin
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, 6 Rong Jing Jie, Beijing 100176, China
| | - Bertal H. Aktas
- Hematology Laboratory for Translational Research, Department of Medicine. Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
| |
Collapse
|
29
|
Liu Y, Lou G, Wu W, Shi Y, Zheng M, Chen Z. Interferon-α sensitizes HBx-expressing hepatocarcinoma cells to chemotherapeutic drugs through inhibition of HBx-mediated NF-κB activation. Virol J 2013; 10:168. [PMID: 23718853 PMCID: PMC3680016 DOI: 10.1186/1743-422x-10-168] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Accepted: 04/11/2013] [Indexed: 01/15/2023] Open
Abstract
Background Hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) is characterized by high chemotherapy resistance; however, the underlying mechanism has not been fully clarified. In addition, HBx protein has been reported to play a key role in virus-mediated hepatocarcinogenesis. Therefore, the present study aims to investigate the role of HBx in the drug-resistance of HBV-related HCC and examine whether such drug-resistance can be reversed by IFN-α treatment. Methods We established HBx-expressing cells by liposome-mediated transfection of HBx into the Huh7 cell line. MTT, Annexin V/PI, and cell cycle assay were used for determining the cellular growth inhibition, apoptosis, and growth arrest, respectively, after treatment with chemical drug. We further used tumor-bearing mice model to compare the tumor growth inhibition efficacy of ADM and 5-FU between the Huh7-HBx group and the control group, as well as the ADM + IFN-α or ADM + IMD treated group and the ADM treated group. SQ-Real time-PCR was performed to analyze the expression of MDR-associated genes and anti-apoptotic genes. Moreover, immunofluorescence and Western blotting were used to determine the subcellular localization of p65 and the phosphorylation of IκBα. Results The IC50 values of Huh7-HBx cells against ADM and Amn were 2.317 and 1.828-folds higher than those of Huh7-3.1 cells, respectively. The apoptosis ratio and growth arrest was significantly lower in Huh7-HBx cells after treatment with ADM. The in vivo experiment also confirmed that the Huh7-HBx group was much more resistant to ADM or 5-FU than the control. Furthermore, the expression of MDR-associated genes, such as MDR1, MRP1, LRP1, and ABCG2, were significantly up-regulated in Huh7-HBx cells, and the NF-κB pathway was activated after HBx gene transfection in Huh7 cells. However, combined with IFN-α in ADM treatment, the HBx induced drug-resistance in Huh7-HBx cells can be partly abolished in in vitro and in vivo models. Moreover, we found that the NF-κB canonical pathway was affected by IFN-α treatment, and the expression of anti-apoptotic genes, such as Gadd45β, Survivin, and c-IAP-1 was down-regulated by IFN-α treatment in a dose-dependent manner. Conclusions HBx protein can induce MDR of HBV-related HCC by activating the NF-κB pathway, which can be partly abolished by IFN-α treatment.
Collapse
Affiliation(s)
- Yanning Liu
- State Key Laboratory of Infectious Disease Diagnosis and Treatment, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China
| | | | | | | | | | | |
Collapse
|
30
|
Liu Y, Lou G, Wu W, Shi Y, Zheng M, Chen Z. Interferon-α sensitizes HBx-expressing hepatocarcinoma cells to chemotherapeutic drugs through inhibition of HBx-mediated NF-κB activation. Virol J 2013. [PMID: 23718853 DOI: 10.1186/1743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) is characterized by high chemotherapy resistance; however, the underlying mechanism has not been fully clarified. In addition, HBx protein has been reported to play a key role in virus-mediated hepatocarcinogenesis. Therefore, the present study aims to investigate the role of HBx in the drug-resistance of HBV-related HCC and examine whether such drug-resistance can be reversed by IFN-α treatment. METHODS We established HBx-expressing cells by liposome-mediated transfection of HBx into the Huh7 cell line. MTT, Annexin V/PI, and cell cycle assay were used for determining the cellular growth inhibition, apoptosis, and growth arrest, respectively, after treatment with chemical drug. We further used tumor-bearing mice model to compare the tumor growth inhibition efficacy of ADM and 5-FU between the Huh7-HBx group and the control group, as well as the ADM + IFN-α or ADM + IMD treated group and the ADM treated group. SQ-Real time-PCR was performed to analyze the expression of MDR-associated genes and anti-apoptotic genes. Moreover, immunofluorescence and Western blotting were used to determine the subcellular localization of p65 and the phosphorylation of IκBα. RESULTS The IC₅₀ values of Huh7-HBx cells against ADM and Amn were 2.317 and 1.828-folds higher than those of Huh7-3.1 cells, respectively. The apoptosis ratio and growth arrest was significantly lower in Huh7-HBx cells after treatment with ADM. The in vivo experiment also confirmed that the Huh7-HBx group was much more resistant to ADM or 5-FU than the control. Furthermore, the expression of MDR-associated genes, such as MDR1, MRP1, LRP1, and ABCG2, were significantly up-regulated in Huh7-HBx cells, and the NF-κB pathway was activated after HBx gene transfection in Huh7 cells. However, combined with IFN-α in ADM treatment, the HBx induced drug-resistance in Huh7-HBx cells can be partly abolished in in vitro and in vivo models. Moreover, we found that the NF-κB canonical pathway was affected by IFN-α treatment, and the expression of anti-apoptotic genes, such as Gadd45β, Survivin, and c-IAP-1 was down-regulated by IFN-α treatment in a dose-dependent manner. CONCLUSIONS HBx protein can induce MDR of HBV-related HCC by activating the NF-κB pathway, which can be partly abolished by IFN-α treatment.
Collapse
Affiliation(s)
- Yanning Liu
- State Key Laboratory of Infectious Disease Diagnosis and Treatment, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China
| | | | | | | | | | | |
Collapse
|
31
|
Chemical genetics reveals a kinase-independent role for protein kinase R in pyroptosis. Nat Chem Biol 2013; 9:398-405. [PMID: 23603659 DOI: 10.1038/nchembio.1236] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 03/21/2013] [Indexed: 12/15/2022]
Abstract
Formation of the inflammasome, a scaffolding complex that activates caspase-1, is important in numerous diseases. Pyroptotic cell death induced by anthrax lethal toxin (LT) is a model for inflammasome-mediated caspase-1 activation. We discovered 7-desacetoxy-6,7-dehydrogedunin (7DG) in a phenotypic screen as a small molecule that protects macrophages from LT-induced death. Using chemical proteomics, we identified protein kinase R (PKR) as the target of 7DG and show that RNAi knockdown of PKR phenocopies treatment with 7DG. Further, we show that PKR's role in ASC assembly and caspase-1 activation induced by several different inflammasome stimuli is independent of PKR's kinase activity, demonstrating that PKR has a previously uncharacterized role in caspase-1 activation and pyroptosis that is distinct from its reported kinase-dependent roles in apoptosis and inflammasome formation in lipopolysaccharide-primed cells. Remarkably, PKR has different roles in two distinct cell death pathways and has a broad role in inflammasome function relevant in other diseases.
Collapse
|
32
|
MDA5 localizes to stress granules, but this localization is not required for the induction of type I interferon. J Virol 2013; 87:6314-25. [PMID: 23536668 DOI: 10.1128/jvi.03213-12] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Virus infection can initiate a type I interferon (IFN-α/β) response via activation of the cytosolic RNA sensors retinoic acid-inducible gene-I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5). Furthermore, it can activate kinases that phosphorylate eukaryotic translation initiation factor 2α (eIF2α), which leads to inhibition of (viral) protein translation and formation of stress granules (SG). Most viruses have evolved mechanisms to suppress these cellular responses. Here, we show that a mutant mengovirus expressing an inactive leader (L) protein, which we have previously shown to be unable to suppress IFN-α/β, triggered SG formation in a protein kinase R (PKR)-dependent manner. Furthermore, we show that infection of cells that are defective in SG formation yielded higher viral RNA levels, suggesting that SG formation acts as an antiviral defense mechanism. Since the induction of both IFN-α/β and SG is suppressed by mengovirus L, we set out to investigate a potential link between these pathways. We observed that MDA5, the intracellular RNA sensor that recognizes picornaviruses, localized to SG. However, activation of the MDA5 signaling pathway did not trigger and was not required for SG formation. Moreover, cells that were unable to form SG-by protein kinase R (PKR) depletion, using cells expressing a nonphosphorylatable eIF2α protein, or by drug treatment that inhibits SG formation-displayed a normal IFN-α/β response. Thus, although MDA5 localizes to SG, this localization seems to be dispensable for induction of the IFN-α/β pathway.
Collapse
|
33
|
Li Y, Xie J, Wu S, Xia J, Zhang P, Liu C, Zhang P, Huang X. Protein kinase regulated by dsRNA downregulates the interferon production in dengue virus- and dsRNA-stimulated human lung epithelial cells. PLoS One 2013; 8:e55108. [PMID: 23372823 PMCID: PMC3555826 DOI: 10.1371/journal.pone.0055108] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 12/18/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Dengue virus (DENV) is found in the tropical and subtropical regions and affects millions of people annually. Currently, no specific vaccine or antiviral treatment against dengue virus is available. Innate immunity has been shown to be important for host resistance to DENV infection. Although protein kinase regulated by double-stranded RNA (PKR) has been found to promote the innate signaling in response to infection by several viruses, its role in the innate response to DENV infection is still unclear. Our study aimed to investigate the role of PKR in DENV-induced innate immune responses. METHODOLOGY/PRINCIPAL FINDINGS By RNAi, silencing of PKR significantly enhanced the expression of interferon (IFN)-β in DENV infected human lung epithelial A549 cells. Western blot and immunofluorescence microscopy data showed that PKR knockdown upregulated the activation of innate signaling cascades including p38 and JNK mitogen-activated protein kinases (MAPKs), interferon regulatory factor-3 and NF-κB, following DENV2 infection. Likewise, a negative regulatory effect of PKR on the IFN production was also observed in poly(IC) challenged cells. Moreover, the PKR knockdown-mediated IFN induction was attenuated by RIG-I or IPS-1 silencing. Finally, overexpression of a catalytically inactive PKR mutant (K296R), but not of a mutant lacking dsRNA binding activity (K64E) or the double mutant (K64EK296R), reversed the IFN induction mediated by PKR knockdown, suggesting that the dsRNA binding activity is required for PKR to downregulate IFN production. CONCLUSIONS/SIGNIFICANCE PKR acts as a negative regulator of IFN induction triggered by DENVs and poly(IC), and this regulation relies on its dsRNA binding activity. These findings reveal a novel regulatory role for PKR in innate immunity, suggesting that PKR might be a promising target for anti-DENV treatments.
Collapse
Affiliation(s)
- Yuye Li
- Department of Immunology, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Jiong Xie
- Department of Immunology, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Siyu Wu
- Department of Immunology, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Jun Xia
- Department of Immunology, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Peifen Zhang
- Department of Immunology, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Chao Liu
- Department of Immunology, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Ping Zhang
- Department of Immunology, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Xi Huang
- Department of Immunology, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| |
Collapse
|
34
|
The virion host shutoff RNase plays a key role in blocking the activation of protein kinase R in cells infected with herpes simplex virus 1. J Virol 2013; 87:3271-6. [PMID: 23302873 DOI: 10.1128/jvi.03049-12] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Earlier studies have shown that active MEK blocks the activation of protein kinase R (PKR), a component of antiviral innate immune responses. In this report we show that the herpes simplex virus 1 virion host shutoff (VHS) RNase protein and MEK (mitogen-activated protein kinase kinase) act cooperatively in blocking the activation of PKR. This conclusion is based on the following. (i) In contrast to viral gene expression in the parental cell line or a cell line expressing a constitutively active MEK, the replication of a VHS mutant is particularly impaired in cells expressing dominant negative MEK. In this cell line PKR is activated by phosphorylation, and the accumulation of several viral proteins is delayed. (ii) In transfected cells, wild-type VHS blocked the activation of PKR, whereas PKR was activated in cells transfected with a mutant VHS or with plasmids encoding the VHS RNase and VP16 and VP22, the two viral proteins that neutralize the RNase activity of VHS. The results suggest that early in infection the VHS RNase degrades RNAs that activate PKR. Coupled with published data, the results suggest that inhibition of activation of PKR or its effect on viral replication is staged early in infection by VHS, postsynthesis of VP16 and VP22 by the γ(1)34.5 protein, and very late in infection by the U(S)11 protein.
Collapse
|
35
|
Abstract
The double-stranded RNA-dependent protein kinase PKR plays multiple roles in cells, in response to different stress situations. As a member of the interferon (IFN)‑Stimulated Genes, PKR was initially recognized as an actor in the antiviral action of IFN, due to its ability to control translation, through phosphorylation, of the alpha subunit of eukaryotic initiation factor 2 (eIF2α). As such, PKR participates in the generation of stress granules, or autophagy and a number of viruses have designed strategies to inhibit its action. However, PKR deficient mice resist most viral infections, indicating that PKR may play other roles in the cell other than just acting as an antiviral agent. Indeed, PKR regulates several signaling pathways, either as an adapter protein and/or using its kinase activity. Here we review the role of PKR as an eIF2α kinase, its participation in the regulation of the NF-κB, p38MAPK and insulin pathways, and we focus on its role during infection with the hepatitis C virus (HCV). PKR binds the HCV IRES RNA, cooperates with some functions of the HCV core protein and may represent a target for NS5A or E2. Novel data points out for a role of PKR as a pro-HCV agent, both as an adapter protein and as an eIF2α-kinase, and in cooperation with the di-ubiquitin-like protein ISG15. Developing pharmaceutical inhibitors of PKR may help in resolving some viral infections as well as stress-related damages.
Collapse
Affiliation(s)
- Stéphanie Dabo
- Unit Hepacivirus and Innate Immunity, Department Virology, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris Cedex 15, France.
| | | |
Collapse
|
36
|
McAllister CS, Taghavi N, Samuel CE. Protein kinase PKR amplification of interferon β induction occurs through initiation factor eIF-2α-mediated translational control. J Biol Chem 2012; 287:36384-92. [PMID: 22948139 PMCID: PMC3476304 DOI: 10.1074/jbc.m112.390039] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 08/31/2012] [Indexed: 12/24/2022] Open
Abstract
The protein kinase PKR is activated by RNA with double-stranded (ds) structure and subsequently impairs translation through phosphorylation of protein synthesis initiation factor eIF-2α. PKR also mediates activation of signal transduction pathways leading to interferon beta (IFN-β) gene induction following virus-infection or RNA transfection. We previously demonstrated in measles virus-infected cells that PKR is required for the maximal induction of IFN-β gene expression by the interferon promoter stimulator gene 1 (IPS-1) adaptor-dependent cytosolic RNA sensor pathway. While both IPS-1 and PKR are important mediators of IFN-β induction, with PKR contributing to an enhanced NF-κB activation, the mechanism by which PKR enhances NF-κB activity and amplifies IFN-β induction is unresolved. Herein we tested the possibility that PKR could activate signal transduction pathways indirectly through translational control responses. Following transfection with synthetic or natural dsRNAs or infection with measles virus, we observed increased mRNA but decreased protein levels for the inhibitor of NF-κB signaling, IκB-α, that correlated with PKR activation and eIF-2α phosphorylation. Importantly, knockdown of PKR increased IκB-α protein levels and impaired IFN-β induction. Additionally, inhibition of translation by cycloheximide treatment rescued IFN-β induction following PKR knockdown but not IPS-1 knockdown. Mutation of eIF-2α to prevent phosphorylation also impaired IFN-β induction in PKR-sufficient virus-infected cells. These results suggest that an eIF-2α-dependent translation inhibition mechanism is sufficient to explain the PKR-mediated amplification of IPS-1-dependent IFN-β induction by foreign RNA.
Collapse
Affiliation(s)
- Christopher S. McAllister
- From the Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California 93106
| | - Nora Taghavi
- From the Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California 93106
| | - Charles E. Samuel
- From the Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California 93106
| |
Collapse
|
37
|
Ling J, Kumar R. Crosstalk between NFkB and glucocorticoid signaling: a potential target of breast cancer therapy. Cancer Lett 2012; 322:119-26. [PMID: 22433713 DOI: 10.1016/j.canlet.2012.02.033] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 02/26/2012] [Accepted: 02/27/2012] [Indexed: 11/24/2022]
Abstract
Breast cancer (BC) is an aggressive and high mortality cancer that can be classified into five molecular subtypes, based on gene expression profiling. The extreme heterogeneity poses difficulties for understanding and treating BC. Among many risk factors, inflammation plays a causal role in BC progression and recurrence, wherein NFkB and glucocorticoid receptor (GR) are critical transcription factors in regulating inflammation. NFkB is generally pro-inflammatory, and GR is anti-inflammatory, constituting a Yin-Yang mode in regulation. Thus, the crosstalk between these two transcription factors exerts even more important functions in determining the survival or apoptosis of BC cells. NFkB is widely involved in the initiation and progression of BC; its inhibitors are emerging as a potent primary or adjuvant therapy. On the other hand, glucocorticoids (GCs) are already used as neo-adjuvant and adjuvant therapies to treat various cancers with remarkable effects to induce apoptosis in leukemia and lymphoma. However, GCs unexpectedly promote cancer cell survival and induce chemo-resistance in BC. To understand this unique transcriptional interplay in BC, in this review we discuss the functions of NFkB and GR in BC development and progression by emphasizing their cross talk at cell signaling and protein interaction levels; and the future perspectives are proposed for the development of new therapeutic approaches for BC based on these signaling pathways.
Collapse
Affiliation(s)
- Jun Ling
- Department of Basic Sciences, The Commonwealth Medical College, Scranton, PA 18509, USA.
| | | |
Collapse
|
38
|
Taghavi N, Samuel CE. Protein kinase PKR catalytic activity is required for the PKR-dependent activation of mitogen-activated protein kinases and amplification of interferon beta induction following virus infection. Virology 2012; 427:208-16. [PMID: 22381929 DOI: 10.1016/j.virol.2012.01.029] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 12/08/2011] [Accepted: 01/25/2012] [Indexed: 12/24/2022]
Abstract
The protein kinase regulated by RNA (PKR) enhances both activation of mitogen-activated protein kinases and the induction of interferon beta (IFN-β) by measles virus defective in C-protein expression (C(ko)). Here we used complementation of human cell lines stably deficient in PKR (PKR(kd)) to probe the basis of these PKR-mediated responses. We found that PKR(kd) HeLa and amnion U cell lines were defective for virus-mediated activation of IFN induction signaling components compared to PKR-sufficient control cells. Complementation of PKR(kd) cells with wildtype PKR, but not with PKR mutants defective in either catalytic activity or dsRNA-binding activity, restored JNK, p38 and ATF-2 phosphorylation and enhanced IFN-β induction following infection. By contrast to mammalian PKR, the Z-DNA binding domain-containing fish homologue of PKR, PKZ, lacked the capacity to enhance C(ko) virus-mediated IFN-β induction. Furthermore, inhibition of virus growth was observed with C(ko)-infected PKR(kd) cells complemented with PKR but not with PKZ.
Collapse
Affiliation(s)
- Nora Taghavi
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | | |
Collapse
|
39
|
Dalton LE, Healey E, Irving J, Marciniak SJ. Phosphoproteins in stress-induced disease. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 106:189-221. [PMID: 22340719 DOI: 10.1016/b978-0-12-396456-4.00003-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The integrated stress response (ISR) is an evolutionarily conserved homeostatic program activated by specific pathological states. These include amino acid deprivation, viral infection, iron deficiency, and the misfolding of proteins within the endoplasmic reticulum (ER), the so-called ER stress. Although apparently disparate, each of these stresses induces phosphorylation of a translation initiation factor, eIF2α, to attenuate new protein translation while simultaneously triggering a transcriptional program. This is achieved by four homologous stress-sensing kinases: GCN2, PKR, HRI, and PERK. In addition to these kinases, mammals possess two specific eIF2α phosphatases, GADD34 and CReP, which play crucial roles in the recovery of protein synthesis following the initial insult. They are not only important in embryonic development but also appear to play important roles in disease, particularly cancer. In this chapter, we discuss each of the eIF2α kinases, in turn, with particular emphasis on their regulation and the new insights provided by recent structural studies. We also discuss the potential for developing novel drug therapies that target the ISR.
Collapse
Affiliation(s)
- Lucy E Dalton
- Division of Respiratory Medicine, Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | | | | | | |
Collapse
|
40
|
Arnaud N, Dabo S, Akazawa D, Fukasawa M, Shinkai-Ouchi F, Hugon J, Wakita T, Meurs EF. Hepatitis C virus reveals a novel early control in acute immune response. PLoS Pathog 2011; 7:e1002289. [PMID: 22022264 PMCID: PMC3192838 DOI: 10.1371/journal.ppat.1002289] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 08/13/2011] [Indexed: 11/19/2022] Open
Abstract
Recognition of viral RNA structures by the intracytosolic RNA helicase RIG-I triggers induction of innate immunity. Efficient induction requires RIG-I ubiquitination by the E3 ligase TRIM25, its interaction with the mitochondria-bound MAVS protein, recruitment of TRAF3, IRF3- and NF-κB-kinases and transcription of Interferon (IFN). In addition, IRF3 alone induces some of the Interferon-Stimulated Genes (ISGs), referred to as early ISGs. Infection of hepatocytes with Hepatitis C virus (HCV) results in poor production of IFN despite recognition of the viral RNA by RIG-I but can lead to induction of early ISGs. HCV was shown to inhibit IFN production by cleaving MAVS through its NS3/4A protease and by controlling cellular translation through activation of PKR, an eIF2α-kinase containing dsRNA-binding domains (DRBD). Here, we have identified a third mode of control of IFN induction by HCV. Using HCVcc and the Huh7.25.CD81 cells, we found that HCV controls RIG-I ubiquitination through the di-ubiquitine-like protein ISG15, one of the early ISGs. A transcriptome analysis performed on Huh7.25.CD81 cells silenced or not for PKR and infected with JFH1 revealed that HCV infection leads to induction of 49 PKR-dependent genes, including ISG15 and several early ISGs. Silencing experiments revealed that this novel PKR-dependent pathway involves MAVS, TRAF3 and IRF3 but not RIG-I, and that it does not induce IFN. Use of PKR inhibitors showed that this pathway requires the DRBD but not the kinase activity of PKR. We then demonstrated that PKR interacts with HCV RNA and MAVS prior to RIG-I. In conclusion, HCV recruits PKR early in infection as a sensor to trigger induction of several IRF3-dependent genes. Among those, ISG15 acts to negatively control the RIG-I/MAVS pathway, at the level of RIG-I ubiquitination.These data give novel insights in the machinery involved in the early events of innate immune response. Hepatitis C Virus (HCV) is a poor interferon (IFN) inducer, despite recognition of its RNA by the cytosolic RNA helicase RIG-I. This is due in part through cleavage of MAVS, a downstream adapter of RIG-I, by the HCV NS3/4A protease and through activation of the eIF2α-kinase PKR to control IFN translation. Here, we show that HCV also inhibits RIG-I activation through the ubiquitin-like protein ISG15 and that HCV triggers rapid induction of 49 genes, including ISG15, through a novel signaling pathway that precedes RIG-I and involves PKR as an adapter to recruit MAVS. Hence, we propose to divide the acute response to HCV infection into one early (PKR) and one late (RIG-I) phase, with the former controlling the latter. Furthermore, these data emphazise the need to check compounds designed as immune adjuvants for activation of the early acute phase before using them to sustain innate immunity.
Collapse
Affiliation(s)
- Noëlla Arnaud
- Institut Pasteur, Hepacivirus and Innate Immunity, Paris, France
| | - Stéphanie Dabo
- Institut Pasteur, Hepacivirus and Innate Immunity, Paris, France
| | - Daisuke Akazawa
- National Institute of Infectious Diseases, Department of Virology II, Tokyo, Japan
| | - Masayoshi Fukasawa
- National Institute of Infectious Diseases, Department of Biochemistry and Cell Biology, Tokyo, Japan
| | - Fumiko Shinkai-Ouchi
- National Institute of Infectious Diseases, Department of Biochemistry and Cell Biology, Tokyo, Japan
| | - Jacques Hugon
- Institut du Fer à Moulin, INSERM UMRS 839, Paris, France
| | - Takaji Wakita
- National Institute of Infectious Diseases, Department of Virology II, Tokyo, Japan
| | - Eliane F. Meurs
- Institut Pasteur, Hepacivirus and Innate Immunity, Paris, France
- * E-mail:
| |
Collapse
|
41
|
Pfaller CK, Li Z, George CX, Samuel CE. Protein kinase PKR and RNA adenosine deaminase ADAR1: new roles for old players as modulators of the interferon response. Curr Opin Immunol 2011; 23:573-82. [PMID: 21924887 PMCID: PMC3190076 DOI: 10.1016/j.coi.2011.08.009] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 08/24/2011] [Indexed: 12/20/2022]
Abstract
Double-stranded RNA (dsRNA) plays a centrally important role in antiviral innate immunity, both for the production of interferon (IFN) and also in the actions of IFN. Among the IFN-inducible gene products are the protein kinase regulated by RNA (PKR) and the adenosine deaminase acting on RNA 1 (ADAR1). PKR is an established key player in the antiviral actions of IFN, through dsRNA-dependent activation and subsequent phosphorylation of protein synthesis initiation factor eIF2α thereby altering the translational pattern in cells. In addition, PKR plays an important role as a positive effector that amplifies the production of IFN. ADAR1 catalyzes the deamination of adenosine (A) in RNA with double-stranded (ds) character, leading to the destabilization of RNA duplex structures and genetic recoding. By contrast to the antiviral and proapoptotic functions associated with PKR, the actions of ADAR1 in some instances are proviral and cell protective as ADAR1 functions as a suppressor of dsRNA-mediated antiviral responses including activation of PKR and interferon regulatory factor 3.
Collapse
Affiliation(s)
- Christian K Pfaller
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | | | | | | |
Collapse
|
42
|
Myskiw C, Arsenio J, Booy EP, Hammett C, Deschambault Y, Gibson SB, Cao J. RNA species generated in vaccinia virus infected cells activate cell type-specific MDA5 or RIG-I dependent interferon gene transcription and PKR dependent apoptosis. Virology 2011; 413:183-93. [PMID: 21354589 DOI: 10.1016/j.virol.2011.01.034] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 01/08/2011] [Accepted: 01/28/2011] [Indexed: 10/18/2022]
Abstract
RNA species produced during virus replication are pathogen-associated molecular patterns (PAMPs) triggering cellular innate immune responses including induction of type I interferon expression and apoptosis. Pattern recognition receptors (PRRs) for these RNAs include the retinoic acid-inducible gene I (RIG-I) like receptors (RLRs) RIG-I and melanoma differentiation associated gene 5 (MDA5) and the dsRNA dependent protein kinase (PKR). Currently, poxvirus PAMPs and their associated PRRs are not well characterized. We report that RNA species generated in vaccinia infected cells can activate MDA5 or RIG-I dependent interferon-β (IFN-β) gene transcription in a cell type-specific manner. These RNA species also induce the activation of apoptosis in a PKR dependent, but MDA5 and RIG-I independent, manner. Collectively our results demonstrate that RNA species generated during vaccinia virus replication are major PAMPs activating apoptosis and IFN-β gene transcription. Moreover, our results delineate the signaling pathways involved in the recognition of RNA-based poxvirus PAMPs.
Collapse
Affiliation(s)
- Chad Myskiw
- Department of Medical Microbiology, University of Manitoba, Winnipeg, Canada R3T 2N2
| | | | | | | | | | | | | |
Collapse
|
43
|
Yang X, Nath A, Opperman MJ, Chan C. The double-stranded RNA-dependent protein kinase differentially regulates insulin receptor substrates 1 and 2 in HepG2 cells. Mol Biol Cell 2010; 21:3449-58. [PMID: 20685959 PMCID: PMC2947480 DOI: 10.1091/mbc.e10-06-0481] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The RNA-dependent protein kinase (PKR), initially known as a virus infection response protein, is found to differentially regulate two major players in the insulin signaling pathway, IRS1 and IRS2. PKR up-regulates the inhibitory phosphorylation of IRS1 and the expression of IRS2 at the transcriptional level. Initially identified to be activated upon virus infection, the double-stranded RNA–dependent protein kinase (PKR) is best known for triggering cell defense responses by phosphorylating eIF-2α, thus suppressing RNA translation. We as well as others showed that the phosphorylation of PKR is down-regulated by insulin. In the present study, we further uncovered a novel function of PKR in regulating the IRS proteins. We found that PKR up-regulates the inhibitory phosphorylation of IRS1 at Ser312, which suppresses the tyrosine phosphorylation of IRS1. This effect of PKR on the phosphorylation of IRS1 is mediated by two other protein kinases, JNK and IKK. In contrast, PKR regulates IRS2, another major IRS family protein in the liver, at the transcriptional rather than the posttranslational level, and this effect is mediated by the transcription factor, FoxO1, which has been previously shown to be regulated by insulin and plays a significant role in glucose homeostasis and energy metabolism. In summary, we found for the first time that initially known as a virus infection response gene, PKR regulates the upstream central transmitters of insulin signaling, IRS1 and IRS2, through different mechanisms.
Collapse
Affiliation(s)
- Xuerui Yang
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824, USA
| | | | | | | |
Collapse
|
44
|
Blalock WL, Bavelloni A, Piazzi M, Faenza I, Cocco L. A role for PKR in hematologic malignancies. J Cell Physiol 2010; 223:572-91. [PMID: 20232306 DOI: 10.1002/jcp.22092] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The double-stranded RNA-dependent kinase PKR has been described for many years as strictly a pro-apoptotic kinase. Recent data suggest that the main purpose of this kinase is damage control and repair following stress and, if all else fails, apoptosis. Aberrant activation of PKR has been reported in numerous neurodegenerative diseases and cancer. Although a subset of myelodysplastic syndromes (MDS) and chronic lymphocytic leukemia contain low levels of PKR expression and activity, elevated PKR activity and/or expression have been detected in a wide range of hematologic malignancies, from bone marrow failure disorders to acute leukemia. With the recent findings that cancers containing elevated PKR activity are highly sensitive to PKR inhibition, we explore the role of PKR in hematologic malignancies, signal transduction pathways affected by PKR, and how PKR may contribute to leukemic transformation.
Collapse
Affiliation(s)
- William L Blalock
- Department of Human Anatomical Sciences, University of Bologna, Bologna, Italy
| | | | | | | | | |
Collapse
|
45
|
Qin Z, Kearney P, Plaisance K, Parsons CH. Pivotal advance: Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded microRNA specifically induce IL-6 and IL-10 secretion by macrophages and monocytes. J Leukoc Biol 2010; 87:25-34. [PMID: 20052801 DOI: 10.1189/jlb.0409251] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Macrophages are an important source of inflammatory cytokines generated during the innate immune response,but in the microenvironment of certain tumors,macrophages promote tumor progression through their preferential secretion of cytokines that support tumor cell growth and suppress antitumoral immune responses. KSHV is the causative agent of KS and lymphomas preferentially arising in immuno compromised patients, and specific cytokines, including IL-6 and IL-10, have been implicated in KSHV-associated cancer pathogenesis. However, the contribution of KSHV-infected macrophages to the cytokine milieu within KSHV-related tumors is unclear. We found that individual KSHV-encoded miRNA induce IL-6 and IL-10 secretion independently and additively by murine macrophages and human myelomonocytic cells. Bioinformatics analysis identified KSHV miRNA binding sites formiR-K12-3 and miR-K12-7 within the 3'UTR of the basic region/leucine zipper motif transcription factor C/EBPbeta, a known regulator of IL-6 and IL-10 transcriptional activation.Subsequent immunoblot analyses revealed that miR-K12-3 and miR-K12-7 preferentially reduce expression of C/EBPbeta p20 (LIP), an isoform of C/EBPbeta known to function as a negative transcription regulator. In addition,RNA interference specifically targeting LIP induced basal secretion of IL-6 and IL-10 by macrophages.Taken together, these data support a role for KSHV miRNA in the programming of macrophage cytokine responses in favor of KSHV-related tumor progression.
Collapse
Affiliation(s)
- Zhiqiang Qin
- Department of Medicine, Hollings Cancer Center, Medical University of South Carolina,Charleston, South Carolina, USA
| | | | | | | |
Collapse
|
46
|
The NS segment of an H5N1 highly pathogenic avian influenza virus (HPAIV) is sufficient to alter replication efficiency, cell tropism, and host range of an H7N1 HPAIV. J Virol 2009; 84:2122-33. [PMID: 20007264 DOI: 10.1128/jvi.01668-09] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
A reassortant avian influenza virus (designated FPV NS GD), carrying the NS-segment of the highly pathogenic avian influenza virus (HPAIV) strain A/Goose/Guangdong/1/96 (GD; H5N1) in the genetic background of the HPAIV strain A/FPV/Rostock/34 (FPV; H7N1), was rescued by reverse genetics. Remarkably, in contrast to the recombinant wild-type FPV (rFPV), the reassortant virus was able to replicate more efficiently in different human cell lines and primary mouse epithelia cells without prior adaptation. Moreover, FPV NS GD caused disease and death in experimentally infected mice and was detected in mouse lungs; in contrast, rFPV was not able to replicate in mice effectively. These results indicated an altered host range and increased virulence. Furthermore FPV NS GD showed pronounced pathogenicity in chicken embryos. In an attempt to define the molecular basis for the apparent differences, we determined that NS1 proteins of the H5N1 and H7N1 strains bound the antiviral kinase PKR and the F2F3 domain of cleavage and polyadenylation specificity factor 30 (CPSF30) with comparable efficiencies in vitro. However, FPV NS GD infection resulted in (i) increased expression of NS1, (ii) faster and stronger PKR inhibition, and (iii) stronger beta interferon promoter inhibition than rFPV. Taken together, the results shed further light on the importance of the NS segment of an H5N1 strain for viral replication, molecular pathogenicity, and host range of HPAIVs and the possible consequences of a reassortment between naturally occurring H7 and H5 type HPAIVs.
Collapse
|
47
|
Morel M, Couturier J, Lafay-Chebassier C, Paccalin M, Page G. PKR, the double stranded RNA-dependent protein kinase as a critical target in Alzheimer's disease. J Cell Mol Med 2009; 13:1476-88. [PMID: 19602051 PMCID: PMC3828860 DOI: 10.1111/j.1582-4934.2009.00849.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Amyloid β-peptide (Aβ) deposits and neurofibrillary tangles are key hallmarks in Alzheimer's disease (AD). Aβ stimulates many signal transducers involved in the neuronal death. However, many mechanisms remain to be elucidated because no definitive therapy of AD exists. Some studies have focused on the control of translation which involves eIF2 and eIF4E, main eukaryotic factors of initiation. The availability of these factors depends on the activation of the double-stranded RNA-dependent protein kinase (PKR) and the mammalian target of rapamycin (mTOR), respectively. mTOR positively regulates the translation while PKR results in a protein synthesis shutdown. Many studies demonstrated that the PKR signalling pathway is up-regulated in cellular and animal models of AD and in the brain of AD patients. Interestingly, our results showed that phosphorylated PKR and eIF2α levels were significantly increased in lymphocytes of AD patients. These modifications were significantly correlated with cognitive and memory test scores performed in AD patients. On the contrary, the mTOR signalling pathway is down-regulated in cellular and animal models of AD. Recently, we showed that p53, regulated protein in development and DNA damage response 1 and tuberous sclerosis complex 2 could represent molecular links between PKR and mTOR signalling pathways. PKR could be an early biomarker of the neuronal death and a critical target for a therapeutic programme in AD.
Collapse
Affiliation(s)
- Milena Morel
- Research Group on Brain Aging (EA 3808) University of Poitiers, Poitiers Cedex, France
| | | | | | | | | |
Collapse
|
48
|
Vaccinia virus E3 suppresses expression of diverse cytokines through inhibition of the PKR, NF-kappaB, and IRF3 pathways. J Virol 2009; 83:6757-68. [PMID: 19369349 DOI: 10.1128/jvi.02570-08] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The vaccinia virus double-stranded RNA binding protein E3 has been demonstrated to inhibit the expression of cytokines, including beta interferon (IFN-beta) and tumor necrosis factor alpha (TNF-alpha). However, few details regarding the molecular mechanisms of this inhibition have been described. Using real-time PCR arrays, we found that E3 suppressed the induction of a diverse array of cytokines representing members of the IFN, interleukin (IL), TNF, and transforming growth factor cytokine families. We discovered that the factor(s) responsible for the induction of IL-6, TNF-alpha, and inhibin beta A (INHBA) was associated with the early and late phases of virus infection. In contrast, the factor(s) which regulates IFN-beta induction was associated with the late phase of replication. We have found that expression of these cytokines can be induced by transfection of cells with RNA isolated from vaccinia virus-infected cells. Moreover, we provide evidence that E3 antagonizes both PKR-dependent and PKR-independent pathways to regulate cytokine expression. PKR-dependent activation of p38 and NF-kappaB was required for vaccinia virus-induced INHBA expression, whereas induction of TNF-alpha required only PKR-dependent NF-kappaB activation. In contrast, induction of IL-6 and IFN-beta was largely PKR independent. IL-6 induction is regulated by NF-kappaB, while IFN-beta induction is mediated by IFN-beta promoter stimulator 1 and IFN regulatory factor 3/NF-kappaB. Collectively, these results indicate that E3 suppresses distinct but interlinked host signaling pathways to inhibit the expression of a diverse array of cytokines.
Collapse
|
49
|
Errington F, Steele L, Prestwich R, Harrington KJ, Pandha HS, Vidal L, de Bono J, Selby P, Coffey M, Vile R, Melcher A. Reovirus activates human dendritic cells to promote innate antitumor immunity. THE JOURNAL OF IMMUNOLOGY 2008; 180:6018-26. [PMID: 18424722 DOI: 10.4049/jimmunol.180.9.6018] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Oncolytic viruses can exert their antitumor activity via direct oncolysis or activation of antitumor immunity. Although reovirus is currently under clinical investigation for the treatment of localized or disseminated cancer, any potential immune contribution to its efficacy has not been addressed. This is the first study to investigate the ability of reovirus to activate human dendritic cells (DC), key regulators of both innate and adaptive immune responses. Reovirus induced DC maturation and stimulated the production of the proinflammatory cytokines IFN-alpha, TNF-alpha, IL-12p70, and IL-6. Activation of DC by reovirus was not dependent on viral replication, while cytokine production (but not phenotypic maturation) was inhibited by blockade of PKR and NF-kappaB signaling. Upon coculture with autologous NK cells, reovirus-activated DC up-regulated IFN-gamma production and increased NK cytolytic activity. Moreover, short-term coculture of reovirus-activated DC with autologous T cells also enhanced T cell cytokine secretion (IL-2 and IFN-gamma) and induced non-Ag restricted tumor cell killing. These data demonstrate for the first time that reovirus directly activates human DC and that reovirus-activated DC stimulate innate killing by not only NK cells, but also T cells, suggesting a novel potential role for T cells in oncolytic virus-induced local tumor cell death. Hence reovirus recognition by DC may trigger innate effector mechanisms to complement the virus's direct cytotoxicity, potentially enhancing the efficacy of reovirus as a therapeutic agent.
Collapse
Affiliation(s)
- Fiona Errington
- Cancer Research U.K., St. James's University Hospital, Beckett Street, Leeds
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Park HR, Cockrell LM, Du Y, Kasinski A, Havel J, Zhao J, Reyes-Turcu F, Wilkinson KD, Fu H. Protein–Protein Interactions. SPRINGER PROTOCOLS HANDBOOKS 2008. [DOI: 10.1007/978-1-60327-375-6_30] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|