1
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Solotchi M, Patel SS. Proofreading mechanisms of the innate immune receptor RIG-I: distinguishing self and viral RNA. Biochem Soc Trans 2024; 52:1131-1148. [PMID: 38884803 DOI: 10.1042/bst20230724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2024] [Revised: 06/02/2024] [Accepted: 06/04/2024] [Indexed: 06/18/2024]
Abstract
The RIG-I-like receptors (RLRs), comprising retinoic acid-inducible gene I (RIG-I), melanoma differentiation-associated gene 5 (MDA5), and laboratory of genetics and physiology 2 (LGP2), are pattern recognition receptors belonging to the DExD/H-box RNA helicase family of proteins. RLRs detect viral RNAs in the cytoplasm and respond by initiating a robust antiviral response that up-regulates interferon and cytokine production. RIG-I and MDA5 complement each other by recognizing different RNA features, and LGP2 regulates their activation. RIG-I's multilayered RNA recognition and proofreading mechanisms ensure accurate viral RNA detection while averting harmful responses to host RNAs. RIG-I's C-terminal domain targets 5'-triphosphate double-stranded RNA (dsRNA) blunt ends, while an intrinsic gating mechanism prevents the helicase domains from non-specifically engaging with host RNAs. The ATPase and RNA translocation activity of RIG-I adds another layer of selectivity by minimizing the lifetime of RIG-I on non-specific RNAs, preventing off-target activation. The versatility of RIG-I's ATPase function also amplifies downstream signaling by enhancing the signaling domain (CARDs) exposure on 5'-triphosphate dsRNA and promoting oligomerization. In this review, we offer an in-depth understanding of the mechanisms RIG-I uses to facilitate viral RNA sensing and regulate downstream activation of the immune system.
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Affiliation(s)
- Mihai Solotchi
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ 08854, U.S.A
- Graduate School of Biomedical Sciences, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, U.S.A
| | - Smita S Patel
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ 08854, U.S.A
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2
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Son S, Park M, Kim J, Lee K. ACE mRNA (Additional Chimeric Element incorporated IVT mRNA) for Enhancing Protein Expression by Modulating Immunogenicity. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2307541. [PMID: 38447169 PMCID: PMC11095206 DOI: 10.1002/advs.202307541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 02/19/2024] [Indexed: 03/08/2024]
Abstract
The development of in vitro transcribed mRNA (IVT mRNA)-based therapeutics/vaccines depends on the management of IVT mRNA immunogenicity. IVT mRNA, which is used for intracellular protein translation, often triggers unwanted immune responses, interfering with protein expression and leading to reduced therapeutic efficacy. Currently, the predominant approach for mitigating immune responses involves the incorporation of costly chemically modified nucleotides like pseudouridine (Ψ) or N1-methylpseudouridine (m1Ψ) into IVT mRNA, raising concerns about expense and the potential misincorporation of amino acids into chemically modified codon sequences. Here, an Additional Chimeric Element incorporated mRNA (ACE mRNA), a novel approach incorporating two segments within a single IVT mRNA structure, is introduced. The first segment retains conventional IVT mRNA components prepared with unmodified nucleotides, while the second, comprised of RNA/DNA chimeric elements, aims to modulate immunogenicity. Notably, ACE mRNA demonstrates a noteworthy reduction in immunogenicity of unmodified IVT mRNA, concurrently demonstrating enhanced protein expression efficiency. The reduced immune responses are based on the ability of RNA/DNA chimeric elements to restrict retinoic acid-inducible gene I (RIG-I) and stimulator of interferon genes (STING)-mediated immune activation. The developed ACE mRNA shows great potential in modulating the immunogenicity of IVT mRNA without the need for chemically modified nucleotides, thereby advancing the safety and efficacy of mRNA-based therapeutics/vaccines.
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Affiliation(s)
- Sora Son
- College of Pharmacy and Research Institute of Pharmaceutical SciencesGyeongsang National UniversityJinjuGyeongsangnam‐do52828Republic of Korea
| | - Minsa Park
- College of Pharmacy and Research Institute of Pharmaceutical SciencesGyeongsang National UniversityJinjuGyeongsangnam‐do52828Republic of Korea
| | - Jin Kim
- College of Pharmacy and Research Institute of Pharmaceutical SciencesGyeongsang National UniversityJinjuGyeongsangnam‐do52828Republic of Korea
| | - Kyuri Lee
- College of Pharmacy and Research Institute of Pharmaceutical SciencesGyeongsang National UniversityJinjuGyeongsangnam‐do52828Republic of Korea
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3
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Muslimov A, Tereshchenko V, Shevyrev D, Rogova A, Lepik K, Reshetnikov V, Ivanov R. The Dual Role of the Innate Immune System in the Effectiveness of mRNA Therapeutics. Int J Mol Sci 2023; 24:14820. [PMID: 37834268 PMCID: PMC10573212 DOI: 10.3390/ijms241914820] [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: 07/13/2023] [Revised: 09/24/2023] [Accepted: 09/28/2023] [Indexed: 10/15/2023] Open
Abstract
Advances in molecular biology have revolutionized the use of messenger RNA (mRNA) as a therapeutic. The concept of nucleic acid therapy with mRNA originated in 1990 when Wolff et al. reported successful expression of proteins in target organs by direct injection of either plasmid DNA or mRNA. It took decades to bring the transfection efficiency of mRNA closer to that of DNA. The next few decades were dedicated to turning in vitro-transcribed (IVT) mRNA from a promising delivery tool for gene therapy into a full-blown therapeutic modality, which changed the biotech market rapidly. Hundreds of clinical trials are currently underway using mRNA for prophylaxis and therapy of infectious diseases and cancers, in regenerative medicine, and genome editing. The potential of IVT mRNA to induce an innate immune response favors its use for vaccination and immunotherapy. Nonetheless, in non-immunotherapy applications, the intrinsic immunostimulatory activity of mRNA directly hinders the desired therapeutic effect since it can seriously impair the target protein expression. Targeting the same innate immune factors can increase the effectiveness of mRNA therapeutics for some indications and decrease it for others, and vice versa. The review aims to present the innate immunity-related 'barriers' or 'springboards' that may affect the development of immunotherapies and non-immunotherapy applications of mRNA medicines.
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Affiliation(s)
- Albert Muslimov
- Scientific Center for Translational Medicine, Sirius University of Science and Technology, Olympic Ave 1, 354340 Sirius, Russia; (V.T.); (D.S.); (V.R.); (R.I.)
- Laboratory of Nano- and Microencapsulation of Biologically Active Substances, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, 195251 St. Petersburg, Russia;
- RM Gorbacheva Research Institute, Pavlov University, L’va Tolstogo 6-8, 197022 St. Petersburg, Russia;
| | - Valeriy Tereshchenko
- Scientific Center for Translational Medicine, Sirius University of Science and Technology, Olympic Ave 1, 354340 Sirius, Russia; (V.T.); (D.S.); (V.R.); (R.I.)
| | - Daniil Shevyrev
- Scientific Center for Translational Medicine, Sirius University of Science and Technology, Olympic Ave 1, 354340 Sirius, Russia; (V.T.); (D.S.); (V.R.); (R.I.)
| | - Anna Rogova
- Laboratory of Nano- and Microencapsulation of Biologically Active Substances, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, 195251 St. Petersburg, Russia;
- Saint-Petersburg Chemical-Pharmaceutical University, Professora Popova 14, 197376 St. Petersburg, Russia
- School of Physics and Engineering, ITMO University, Lomonosova 9, 191002 St. Petersburg, Russia
| | - Kirill Lepik
- RM Gorbacheva Research Institute, Pavlov University, L’va Tolstogo 6-8, 197022 St. Petersburg, Russia;
| | - Vasiliy Reshetnikov
- Scientific Center for Translational Medicine, Sirius University of Science and Technology, Olympic Ave 1, 354340 Sirius, Russia; (V.T.); (D.S.); (V.R.); (R.I.)
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Prospekt Akad. Lavrentyeva 10, 630090 Novosibirsk, Russia
| | - Roman Ivanov
- Scientific Center for Translational Medicine, Sirius University of Science and Technology, Olympic Ave 1, 354340 Sirius, Russia; (V.T.); (D.S.); (V.R.); (R.I.)
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4
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Sato H, Hara T, Otsuka C, Arao Y, Tsuji Y, Hamano Y, Ogita M, di Luccio E, Hirotsu T, Vecchione A, Ishii H. m6 RNA methylation: an emerging common target in the immune response to cancer and severe acute respiratory syndrome-coronavirus-2 infection. EXPLORATION OF MEDICINE 2023. [DOI: 10.37349/emed.2023.00127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
m6A RNA methylation, a predominant type of RNA modification, is involved in regulating mRNA splicing, stability, and translation as well as the interaction between nucleoproteins and noncoding RNAs. Recent studies have revealed that m6A RNA methylation plays a critical role in the self-to-non-self-recognition of immune cells against endogenous mutations in cancer and exogenous organism-related infections. As an epigenetic mechanism, m6A RNA modification induces immune cell signal transduction, which is altered in the tumor microenvironment, as detected in liquid biopsy. Furthermore, m6A RNA methylation-related inflammation is involved in the cellular response to viral infections, including the emerging severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection. Given the importance of the immune response in maintaining homeostasis in higher eukaryotes, m6A RNA methylation could be useful not only for the early detection of cancer but also for SARS-CoV-2 screening during a global pandemic.
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Affiliation(s)
- Hiromichi Sato
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan; Department of Gastrointestinal Surgery, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan
| | - Tomoaki Hara
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan
| | - Chihiro Otsuka
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan
| | - Yasuko Arao
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan
| | - Yoshiko Tsuji
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan
| | - Yumiko Hamano
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan
| | - Mirei Ogita
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan
| | - Eric di Luccio
- Hirotsu Bio Science Inc., Chiyoda-Ku, Tokyo 102-0094, Japan
| | | | - Andrea Vecchione
- Department of Clinical and Molecular Medicine, Sapienza University of Rome, Santo Andrea Hospital, Via di Grottarossa, 1035-00189 Rome, Italy
| | - Hideshi Ishii
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan
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5
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Nguyen LL, Watson ZL, Ortega R, Woodruff ER, Jordan KR, Iwanaga R, Yamamoto TM, Bailey CA, Jeong AD, Guntupalli SR, Behbakht K, Gbaja V, Arnoult N, Chuong EB, Bitler BG. Combinatory EHMT and PARP inhibition induces an interferon response and a CD8 T cell-dependent tumor regression in PARP inhibitor-resistant models. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.23.529773. [PMID: 36865165 PMCID: PMC9980116 DOI: 10.1101/2023.02.23.529773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Euchromatic histone lysine methyltransferases 1 and 2 (EHMT1/2), which catalyze demethylation of histone H3 lysine 9 (H3K9me2), contribute to tumorigenesis and therapy resistance through unknown mechanisms of action. In ovarian cancer, EHMT1/2 and H3K9me2 are directly linked to acquired resistance to poly-ADP-ribose polymerase (PARP) inhibitors and are correlated with poor clinical outcomes. Using a combination of experimental and bioinformatic analyses in several PARP inhibitor resistant ovarian cancer models, we demonstrate that combinatory inhibition of EHMT and PARP is effective in treating PARP inhibitor resistant ovarian cancers. Our in vitro studies show that combinatory therapy reactivates transposable elements, increases immunostimulatory dsRNA formation, and elicits several immune signaling pathways. Our in vivo studies show that both single inhibition of EHMT and combinatory inhibition of EHMT and PARP reduces tumor burden, and that this reduction is dependent on CD8 T cells. Together, our results uncover a direct mechanism by which EHMT inhibition helps to overcome PARP inhibitor resistance and shows how an epigenetic therapy can be used to enhance anti-tumor immunity and address therapy resistance.
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Affiliation(s)
- Lily L. Nguyen
- Molecular Cellular Developmental Biology, The University of Colorado Boulder, Boulder, CO 80309, USA
| | - Zachary L. Watson
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO, 80045
| | - Raquel Ortega
- Molecular Cellular Developmental Biology, The University of Colorado Boulder, Boulder, CO 80309, USA
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO, 80045
| | - Elizabeth R. Woodruff
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO, 80045
| | - Kimberly R. Jordan
- Department of Immunology and Microbiology, The University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ritsuko Iwanaga
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO, 80045
| | - Tomomi M. Yamamoto
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO, 80045
| | - Courtney A. Bailey
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO, 80045
| | - Abigail D. Jeong
- Molecular Cellular Developmental Biology, The University of Colorado Boulder, Boulder, CO 80309, USA
| | - Saketh R. Guntupalli
- Department of Obstetrics & Gynecology, Division of Gynecologic Oncology, The University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Kian Behbakht
- Department of Obstetrics & Gynecology, Division of Gynecologic Oncology, The University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | | | - Nausica Arnoult
- Molecular Cellular Developmental Biology, The University of Colorado Boulder, Boulder, CO 80309, USA
| | - Edward B. Chuong
- Molecular Cellular Developmental Biology, The University of Colorado Boulder, Boulder, CO 80309, USA
| | - Benjamin G. Bitler
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO, 80045
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6
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Miyamoto M, Himeda T, Ishihara K, Okuwa T, Kobayashi D, Nameta M, Karasawa Y, Chunhaphinyokul B, Yoshida Y, Tanaka N, Higuchi M, Komuro A. Theilovirus 3C Protease Cleaves the C-Terminal Domain of the Innate Immune RNA Sensor, Melanoma Differentiation-Associated Gene 5, and Impairs Double-Stranded RNA-Mediated IFN Response. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 210:335-347. [PMID: 36525065 DOI: 10.4049/jimmunol.2200565] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 11/09/2022] [Indexed: 01/04/2023]
Abstract
Melanoma differentiation-associated gene 5 (MDA5), a member of the retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs), has pivotal roles in innate immune responses against many positive-stranded RNA viruses, including picornavirus and coronavirus. Upon engagement with dsRNA derived from viral infection, MDA5 initiates coordinated signal transduction leading to type I IFN induction to restrict viral replication. In this study, we describe a targeted cleavage events of MDA5 by the 3C protease from Theilovirus. Upon ectopic expression of theilovirus 3C protease from Saffold virus or Theiler's murine encephalomyelitis virus but not encephalomyocarditis virus, fragments of cleaved MDA5 were observed in a dose-dependent manner. When enzymatically inactive Theilovirus 3C protease was expressed, MDA5 cleavage was completely abrogated. Mass spectrometric analysis identified two cleavage sites at the C terminus of MDA5, cleaving off one of the RNA-binding domains. The same cleavage pattern was observed during Theilovirus infection. The cleavage of MDA5 by Theilovirus protease impaired ATP hydrolysis, RNA binding, and filament assembly on RNA, resulting in dysfunction of MDA5 as an innate immune RNA sensor for IFN induction. Furthermore, the cleavage-resistant MDA5 mutant against the 3C protease showed an enhanced IFN response during Saffold virus infection, indicating that Theilovirus has a strategy to circumvent the antiviral immune response by cleaving MDA5 using 3C protease. In summary, these data suggest MDA5 cleavage by 3C protease as a novel immune evasive strategy of Theilovirus.
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Affiliation(s)
- Masahiko Miyamoto
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
| | - Toshiki Himeda
- Department of Microbiology, Kanazawa Medical University School of Medicine, Ishikawa, Japan
| | - Kazuki Ishihara
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
| | - Takako Okuwa
- Department of Microbiology, Kanazawa Medical University School of Medicine, Ishikawa, Japan
| | - Daiki Kobayashi
- Omics Unit, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Masaaki Nameta
- Electron Microscope Core Facility, Niigata University, Niigata, Japan
| | - Yu Karasawa
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
| | - Benyapa Chunhaphinyokul
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
| | - Yutaka Yoshida
- Department of Structural Pathology, Kidney Research Center, Niigata University, Niigata, Japan; and
| | - Nobuyuki Tanaka
- Division of Tumor Immunology, Miyagi Cancer Center Research Institute, Medeshima-Shiode, Natori, Miyagi, Japan
| | - Masaya Higuchi
- Department of Microbiology, Kanazawa Medical University School of Medicine, Ishikawa, Japan
| | - Akihiko Komuro
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
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7
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Wang H, Yin J, Gu X, Shao W, Jia Z, Chen H, Xia W. Immune Regulator Retinoic Acid-Inducible Gene I (RIG-I) in the Pathogenesis of Cardiovascular Disease. Front Immunol 2022; 13:893204. [PMID: 35693778 PMCID: PMC9178270 DOI: 10.3389/fimmu.2022.893204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/28/2022] [Indexed: 11/24/2022] Open
Abstract
Retinoic acid-inducible gene I (RIG-I) is a cytosolic pattern recognition receptor that contains two CARD domains, an RNA helicase domain, and a C-terminal domain. RIG-I initiates antiviral innate immunity by recognizing exogenous viral RNAs/DNAs. However, some studies have reported that RIG-I activation leads to damage in various organs and tissues in diverse circumstances. Recent studies have shown that RIG-I is involved in cancer, lupus nephritis, immunoglobulin A nephropathy, Crohn’s disease, and atherosclerosis. These reports indicate that RIG-I not only participates in antiviral signaling pathways but also exerts an influence on non-viral infectious diseases. RIG-I is widely expressed in immune and non-immune cells including smooth muscle cells, endothelial cells, and cardiomyocytes. A succinct overview of RIG-I and its signaling pathways, with respect to the cardiovascular system, will aid in the development of novel therapeutics for cardiovascular diseases. In this review, we summarize the structure, activation, signaling pathways, and role of RIG-I in cardiovascular diseases.
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Affiliation(s)
- Hao Wang
- Department of Clinical Laboratory, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Jie Yin
- Department of Cardiology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Xinyan Gu
- School of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Wenhui Shao
- School of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Zhanjun Jia
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
- Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
- *Correspondence: Weiwei Xia, ; Zhanjun Jia, ; Hongbing Chen,
| | - Hongbing Chen
- Department of Clinical Laboratory, Children’s Hospital of Nanjing Medical University, Nanjing, China
- *Correspondence: Weiwei Xia, ; Zhanjun Jia, ; Hongbing Chen,
| | - Weiwei Xia
- Department of Clinical Laboratory, Children’s Hospital of Nanjing Medical University, Nanjing, China
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
- Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
- *Correspondence: Weiwei Xia, ; Zhanjun Jia, ; Hongbing Chen,
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8
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Schweibenz BD, Devarkar SC, Solotchi M, Craig C, Zheng J, Pascal BD, Gokhale S, Xie P, Griffin PR, Patel SS. The intrinsically disordered CARDs-Helicase linker in RIG-I is a molecular gate for RNA proofreading. EMBO J 2022; 41:e109782. [PMID: 35437807 PMCID: PMC9108607 DOI: 10.15252/embj.2021109782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 03/28/2022] [Accepted: 04/04/2022] [Indexed: 01/22/2023] Open
Abstract
The innate immune receptor RIG-I provides a first line of defense against viral infections. Viral RNAs are recognized by RIG-I's C-terminal domain (CTD), but the RNA must engage the helicase domain to release the signaling CARD (Caspase Activation and Recruitment Domain) domains from their autoinhibitory CARD2:Hel2i interactions. Because the helicase itself lacks RNA specificity, mechanisms to proofread RNAs entering the helicase domain must exist. Although such mechanisms would be crucial in preventing aberrant immune responses by non-specific RNAs, they remain largely uncharacterized to date. This study reveals a previously unknown proofreading mechanism through which RIG-I ensures that the helicase engages RNAs explicitly recognized by the CTD. A crucial part of this mechanism involves the intrinsically disordered CARDs-Helicase Linker (CHL), which connects the CARDs to the helicase subdomain Hel1. CHL uses its negatively charged regions to antagonize incoming RNAs electrostatically. In addition to this RNA gating function, CHL is essential for stabilization of the CARD2:Hel2i interface. Overall, we uncover that the CHL and CARD2:Hel2i interface work together to establish a tunable gating mechanism that allows CTD-chosen RNAs to bind the helicase domain, while at the same time blocking non-specific RNAs. These findings also indicate that CHL could represent a novel target for RIG-I-based therapeutics.
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Affiliation(s)
- Brandon D Schweibenz
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA.,Graduate Program in Biochemistry, Rutgers University, Piscataway, NJ, USA
| | - Swapnil C Devarkar
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA.,Graduate Program in Biochemistry, Rutgers University, Piscataway, NJ, USA
| | - Mihai Solotchi
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA.,Cell and Development Biology, Rutgers University, Piscataway, NJ, USA
| | - Candice Craig
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA.,Graduate Program in Biochemistry, Rutgers University, Piscataway, NJ, USA
| | - Jie Zheng
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL, USA
| | - Bruce D Pascal
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL, USA
| | - Samantha Gokhale
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA.,Cellular and Molecular Pharmacology, Rutgers University, Piscataway, NJ, USA
| | - Ping Xie
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA.,Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
| | - Patrick R Griffin
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL, USA.,Department of Integrative Structural and Computational Biology, Jupiter, FL, USA
| | - Smita S Patel
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA.,Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
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9
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Activation of Innate Immunity by Therapeutic Nucleic Acids. Int J Mol Sci 2021; 22:ijms222413360. [PMID: 34948156 PMCID: PMC8704878 DOI: 10.3390/ijms222413360] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 12/24/2022] Open
Abstract
Nucleic acid-based therapeutics have gained increased attention during recent decades because of their wide range of application prospects. Immunostimulatory nucleic acids represent a promising class of potential drugs for the treatment of tumoral and viral diseases due to their low toxicity and stimulation of the body’s own innate immunity by acting on the natural mechanisms of its activation. The repertoire of nucleic acids that directly interact with the components of the immune system is expanding with the improvement of both analytical methods and methods for the synthesis of nucleic acids and their derivatives. Despite the obvious progress in this area, the problem of delivering therapeutic acids to target cells as well as the unresolved issue of achieving a specific therapeutic effect based on activating the mechanism of interferon and anti-inflammatory cytokine synthesis. Minimizing the undesirable effects of excessive secretion of inflammatory cytokines remains an unsolved task. This review examines recent data on the types of immunostimulatory nucleic acids, the receptors interacting with them, and the mechanisms of immunity activation under the action of these molecules. Finally, data on immunostimulatory nucleic acids in ongoing and completed clinical trials will be summarized.
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10
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Takeda Y, Chijimatsu R, Vecchione A, Arai T, Kitagawa T, Ofusa K, Yabumoto M, Hirotsu T, Eguchi H, Doki Y, Ishii H. Impact of One-Carbon Metabolism-Driving Epitranscriptome as a Therapeutic Target for Gastrointestinal Cancer. Int J Mol Sci 2021; 22:ijms22147278. [PMID: 34298902 PMCID: PMC8306097 DOI: 10.3390/ijms22147278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 12/22/2022] Open
Abstract
One-carbon (1C) metabolism plays a key role in biological functions linked to the folate cycle. These include nucleotide synthesis; the methylation of DNA, RNA, and proteins in the methionine cycle; and transsulfuration to maintain the redox condition of cancer stem cells in the tumor microenvironment. Recent studies have indicated that small therapeutic compounds affect the mitochondrial folate cycle, epitranscriptome (RNA methylation), and reactive oxygen species reactions in cancer cells. The epitranscriptome controls cellular biochemical reactions, but is also a platform for cell-to-cell interaction and cell transformation. We present an update of recent advances in the study of 1C metabolism related to cancer and demonstrate the areas where further research is needed. We also discuss approaches to therapeutic drug discovery using animal models and propose further steps toward developing precision cancer medicine.
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Affiliation(s)
- Yu Takeda
- Center of Medical Innovation and Translational Research, Department of Medical Data Science, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan; (Y.T.); (R.C.); (T.A.); (T.K.); (K.O.); (M.Y.); (T.H.)
- Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan; (H.E.); (Y.D.)
| | - Ryota Chijimatsu
- Center of Medical Innovation and Translational Research, Department of Medical Data Science, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan; (Y.T.); (R.C.); (T.A.); (T.K.); (K.O.); (M.Y.); (T.H.)
| | - Andrea Vecchione
- Department of Clinical and Molecular Medicine, University of Rome “Sapienza”, Santo Andrea Hospital, Via di Grottarossa, 1035-00189 Rome, Italy;
| | - Takahiro Arai
- Center of Medical Innovation and Translational Research, Department of Medical Data Science, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan; (Y.T.); (R.C.); (T.A.); (T.K.); (K.O.); (M.Y.); (T.H.)
- Unitech Co., Ltd., Kashiwa 277-0005, Japan
| | - Toru Kitagawa
- Center of Medical Innovation and Translational Research, Department of Medical Data Science, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan; (Y.T.); (R.C.); (T.A.); (T.K.); (K.O.); (M.Y.); (T.H.)
- Kyowa-kai Medical Corporation, Osaka 540-0008, Japan
| | - Ken Ofusa
- Center of Medical Innovation and Translational Research, Department of Medical Data Science, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan; (Y.T.); (R.C.); (T.A.); (T.K.); (K.O.); (M.Y.); (T.H.)
- Food and Life-Science Laboratory, Prophoenix Division, Idea Consultants, Inc., Osaka 559-8519, Japan
| | - Masami Yabumoto
- Center of Medical Innovation and Translational Research, Department of Medical Data Science, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan; (Y.T.); (R.C.); (T.A.); (T.K.); (K.O.); (M.Y.); (T.H.)
- Kinshu-kai Medical Corporation, Osaka 558-0041, Japan
| | - Takaaki Hirotsu
- Center of Medical Innovation and Translational Research, Department of Medical Data Science, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan; (Y.T.); (R.C.); (T.A.); (T.K.); (K.O.); (M.Y.); (T.H.)
- Hirotsu Bio Science Inc., Tokyo 107-0062, Japan
| | - Hidetoshi Eguchi
- Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan; (H.E.); (Y.D.)
| | - Yuichiro Doki
- Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan; (H.E.); (Y.D.)
| | - Hideshi Ishii
- Center of Medical Innovation and Translational Research, Department of Medical Data Science, Osaka University Graduate School of Medicine, Suita, Yamadaoka 2-2, Osaka 565-0871, Japan; (Y.T.); (R.C.); (T.A.); (T.K.); (K.O.); (M.Y.); (T.H.)
- Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan; (H.E.); (Y.D.)
- Correspondence: ; Tel.: +81-(0)6-6210-8406 (ext. 8405); Fax: +81-(0)6-6210-8407
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11
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Khan MI, Nur SM, Adhami V, Mukhtar H. Epigenetic regulation of RNA sensors: Sentinels of immune response. Semin Cancer Biol 2021; 83:413-421. [PMID: 33484869 DOI: 10.1016/j.semcancer.2020.12.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/11/2022]
Abstract
Living host system possess mechanisms like innate immune system to combat against inflammation, stress singling, and cancer. These mechanisms are initiated by PAMP and DAMP mediated recognition by PRR. PRR is consist of variety of nucleic acid sensors like-RNA sensors. They play crucial role in identifying exogenous and endogenous RNA molecules, which subsequently mediate pro/inflammatory cytokine, IFN and ISGs response in traumatized or tumorigenic conditions. The sensors can sensitize wide range of nucleic acid particle in term of size and structure, while each category sensors belongs subclasses with differentially expressed in cell and distinguished functioning mechanisms. They are also able to make comparison between self and non-self-nucleic acid molecules through specific mechanisms. Besides exhibiting anti-inflammatory and anti-tumorigenic responses, RNA sensors cover the broad spectrum of response mechanisms. Transcriptionally RNA sensors undergo with tight epigenetic regulations. In this review study, we will be going to discuss about the details of RNA sensors, their functional mechanisms and epi-transactional regulations.
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Affiliation(s)
- Mohammad Imran Khan
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
| | - Suza Mohammad Nur
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Vaqar Adhami
- Department of Dermatology, School of Medicine and Public Health, University of Wisconsin, Madison, USA
| | - Hasan Mukhtar
- Department of Dermatology, School of Medicine and Public Health, University of Wisconsin, Madison, USA.
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12
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Blum SI, Tse HM. Innate Viral Sensor MDA5 and Coxsackievirus Interplay in Type 1 Diabetes Development. Microorganisms 2020; 8:microorganisms8070993. [PMID: 32635205 PMCID: PMC7409145 DOI: 10.3390/microorganisms8070993] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/01/2020] [Accepted: 07/01/2020] [Indexed: 12/12/2022] Open
Abstract
Type 1 diabetes (T1D) is a polygenic autoimmune disease characterized by immune-mediated destruction of insulin-producing β-cells. The concordance rate for T1D in monozygotic twins is ≈30-50%, indicating that environmental factors also play a role in T1D development. Previous studies have demonstrated that enterovirus infections such as coxsackievirus type B (CVB) are associated with triggering T1D. Prior to autoantibody development in T1D, viral RNA and antibodies against CVB can be detected within the blood, stool, and pancreata. An innate pathogen recognition receptor, melanoma differentiation-associated protein 5 (MDA5), which is encoded by the IFIH1 gene, has been associated with T1D onset. It is unclear how single nucleotide polymorphisms in IFIH1 alter the structure and function of MDA5 that may lead to exacerbated antiviral responses contributing to increased T1D-susceptibility. Binding of viral dsRNA via MDA5 induces synthesis of antiviral proteins such as interferon-alpha and -beta (IFN-α/β). Viral infection and subsequent IFN-α/β synthesis can lead to ER stress within insulin-producing β-cells causing neo-epitope generation, activation of β-cell-specific autoreactive T cells, and β-cell destruction. Therefore, an interplay between genetics, enteroviral infections, and antiviral responses may be critical for T1D development.
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13
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Lin H, Cao X. Nuclear innate sensors for nucleic acids in immunity and inflammation. Immunol Rev 2020; 297:162-173. [PMID: 32564422 DOI: 10.1111/imr.12893] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/26/2020] [Accepted: 05/28/2020] [Indexed: 12/19/2022]
Abstract
Innate sensors recognize pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs) to initiate innate immune response by activating downstream signaling. These evolutionarily conserved innate sensors usually locate in the plasma membrane or cytoplasm. However, the nucleus-localized innate sensors are recently found to detect pathogenic nucleic acids for initiating innate response, demonstrating a complicated crosstalk with cytoplasmic sensors and signaling molecules to form an elaborate tiered innate signaling network between nucleus and cytoplasm. Furthermore, these nuclear innate sensors evolve varied mechanisms for discriminating self from non-self nucleic acids to maintain immune homeostasis and avoid autoinflammatory immune response. In this review, we summarize the recent findings on the identification of nuclear innate sensors for nucleic acids, such as hnRNPA2B1, IFI16, SAFA, and their roles in host defense and inflammatory response.
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Affiliation(s)
- Hongyu Lin
- Center for Immunotherapy, Institute of Basic Medical Sciences, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Xuetao Cao
- Center for Immunotherapy, Institute of Basic Medical Sciences, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.,Laboratory of Immunity and Inflammation, College of Life Science, Nankai University, Tianjin, China
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14
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Adar RNA editing-dependent and -independent effects are required for brain and innate immune functions in Drosophila. Nat Commun 2020; 11:1580. [PMID: 32221286 PMCID: PMC7101428 DOI: 10.1038/s41467-020-15435-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 02/24/2020] [Indexed: 12/31/2022] Open
Abstract
ADAR RNA editing enzymes are high-affinity dsRNA-binding proteins that deaminate adenosines to inosines in pre-mRNA hairpins and also exert editing-independent effects. We generated a Drosophila AdarE374A mutant strain encoding a catalytically inactive Adar with CRISPR/Cas9. We demonstrate that Adar adenosine deamination activity is necessary for normal locomotion and prevents age-dependent neurodegeneration. The catalytically inactive protein, when expressed at a higher than physiological level, can rescue neurodegeneration in Adar mutants, suggesting also editing-independent effects. Furthermore, loss of Adar RNA editing activity leads to innate immune induction, indicating that Drosophila Adar, despite being the homolog of mammalian ADAR2, also has functions similar to mammalian ADAR1. The innate immune induction in fly Adar mutants is suppressed by silencing of Dicer-2, which has a RNA helicase domain similar to MDA5 that senses unedited dsRNAs in mammalian Adar1 mutants. Our work demonstrates that the single Adar enzyme in Drosophila unexpectedly has dual functions.
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15
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Brisse M, Ly H. Comparative Structure and Function Analysis of the RIG-I-Like Receptors: RIG-I and MDA5. Front Immunol 2019; 10:1586. [PMID: 31379819 PMCID: PMC6652118 DOI: 10.3389/fimmu.2019.01586] [Citation(s) in RCA: 218] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 06/25/2019] [Indexed: 12/12/2022] Open
Abstract
RIG-I (Retinoic acid-inducible gene I) and MDA5 (Melanoma Differentiation-Associated protein 5), collectively known as the RIG-I-like receptors (RLRs), are key protein sensors of the pathogen-associated molecular patterns (PAMPs) in the form of viral double-stranded RNA (dsRNA) motifs to induce expression of type 1 interferons (IFN1) (IFNα and IFNβ) and other pro-inflammatory cytokines during the early stage of viral infection. While RIG-I and MDA5 share many genetic, structural and functional similarities, there is increasing evidence that they can have significantly different strategies to recognize different pathogens, PAMPs, and in different host species. This review article discusses the similarities and differences between RIG-I and MDA5 from multiple perspectives, including their structures, evolution and functional relationships with other cellular proteins, their differential mechanisms of distinguishing between host and viral dsRNAs and interactions with host and viral protein factors, and their immunogenic signaling. A comprehensive comparative analysis can help inform future studies of RIG-I and MDA5 in order to fully understand their functions in order to optimize potential therapeutic approaches targeting them.
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Affiliation(s)
- Morgan Brisse
- Biochemistry, Molecular Biology, and Biophysics Graduate Program, University of Minnesota, Twin Cities, St. Paul, MN, United States
- Department of Veterinary & Biomedical Sciences, University of Minnesota, Twin Cities, St. Paul, MN, United States
| | - Hinh Ly
- Department of Veterinary & Biomedical Sciences, University of Minnesota, Twin Cities, St. Paul, MN, United States
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16
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Mechanisms of Non-segmented Negative Sense RNA Viral Antagonism of Host RIG-I-Like Receptors. J Mol Biol 2019; 431:4281-4289. [PMID: 31202887 DOI: 10.1016/j.jmb.2019.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 05/29/2019] [Accepted: 06/05/2019] [Indexed: 12/25/2022]
Abstract
The pattern recognition receptors RIG-I-like receptors (RLRs) are critical molecules for cytosolic viral recognition and for subsequent activation of type I interferon production. The interferon signaling pathway plays a key role in viral detection and generating antiviral responses. Among the many pathogens, the non-segmented negative sense RNA viruses target the RLR pathway using a variety of mechanisms. Here, I review the current state of knowledge on the molecular mechanisms that allow non-segmented negative sense RNA virus recognition and antagonism of RLRs.
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17
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Lässig C, Lammens K, Gorenflos López JL, Michalski S, Fettscher O, Hopfner KP. Unified mechanisms for self-RNA recognition by RIG-I Singleton-Merten syndrome variants. eLife 2018; 7:e38958. [PMID: 30047865 PMCID: PMC6086658 DOI: 10.7554/elife.38958] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 07/24/2018] [Indexed: 12/13/2022] Open
Abstract
The innate immune sensor retinoic acid-inducible gene I (RIG-I) detects cytosolic viral RNA and requires a conformational change caused by both ATP and RNA binding to induce an active signaling state and to trigger an immune response. Previously, we showed that ATP hydrolysis removes RIG-I from lower-affinity self-RNAs (Lässig et al., 2015), revealing how ATP turnover helps RIG-I distinguish viral from self-RNA and explaining why a mutation in a motif that slows down ATP hydrolysis causes the autoimmune disease Singleton-Merten syndrome (SMS). Here we show that a different, mechanistically unexplained SMS variant, C268F, which is localized in the ATP-binding P-loop, can signal independently of ATP but is still dependent on RNA. The structure of RIG-I C268F in complex with double-stranded RNA reveals that C268F helps induce a structural conformation in RIG-I that is similar to that induced by ATP. Our results uncover an unexpected mechanism to explain how a mutation in a P-loop ATPase can induce a gain-of-function ATP state in the absence of ATP.
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Affiliation(s)
- Charlotte Lässig
- Department of BiochemistryLudwig-Maximilians-Universität MünchenMunichGermany
- Gene Center, Ludwig-Maximilians-Universität MünchenMunichGermany
| | - Katja Lammens
- Department of BiochemistryLudwig-Maximilians-Universität MünchenMunichGermany
- Gene Center, Ludwig-Maximilians-Universität MünchenMunichGermany
| | - Jacob Lucián Gorenflos López
- Department of BiochemistryLudwig-Maximilians-Universität MünchenMunichGermany
- Gene Center, Ludwig-Maximilians-Universität MünchenMunichGermany
| | - Sebastian Michalski
- Department of BiochemistryLudwig-Maximilians-Universität MünchenMunichGermany
- Gene Center, Ludwig-Maximilians-Universität MünchenMunichGermany
| | - Olga Fettscher
- Department of BiochemistryLudwig-Maximilians-Universität MünchenMunichGermany
- Gene Center, Ludwig-Maximilians-Universität MünchenMunichGermany
| | - Karl-Peter Hopfner
- Department of BiochemistryLudwig-Maximilians-Universität MünchenMunichGermany
- Gene Center, Ludwig-Maximilians-Universität MünchenMunichGermany
- Center for Integrated Protein Science MunichMunichGermany
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18
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Abstract
In a recent Cell paper, Jiang et al. (2018) have shown that lnc-Lsm3b, a long non-coding RNA induced by type I IFN late in the infection in mouse macrophages, prevents further activation of RIG-I acting as a decoy for RIG-I.
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Affiliation(s)
- Dominique Garcin
- Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, 1 rue Michel Servet, 1211, Geneva 4, Switzerland.
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19
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Arenaviral Nucleoproteins Suppress PACT-Induced Augmentation of RIG-I Function To Inhibit Type I Interferon Production. J Virol 2018; 92:JVI.00482-18. [PMID: 29669840 DOI: 10.1128/jvi.00482-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 04/13/2018] [Indexed: 12/28/2022] Open
Abstract
RIG-I is a major cytoplasmic sensor of viral pathogen-associated molecular pattern (PAMP) RNA and induces type I interferon (IFN) production upon viral infection. A double-stranded RNA (dsRNA)-binding protein, PACT, plays an important role in potentiating RIG-I function. We have shown previously that arenaviral nucleoproteins (NPs) suppress type I IFN production via their RNase activity to degrade PAMP RNA. We report here that NPs of arenaviruses block the PACT-induced enhancement of RIG-I function to mediate type I IFN production and that this inhibition is dependent on the RNase function of NPs, which is different from that of a known mechanism of other viral proteins to abolish the interaction between PACT and RIG-I. To understand the biological roles of PACT and RIG-I in authentic arenavirus infection, we analyze growth kinetics of recombinant Pichinde virus (PICV), a prototypical arenavirus, in RIG-I knockout (KO) and PACT KO mouse embryonic fibroblast (MEF) cells. Wild-type (WT) PICV grew at higher titers in both KO MEF lines than in normal MEFs, suggesting the important roles of these cellular proteins in restricting virus replication. PICV carrying the NP RNase catalytically inactive mutation could not grow in normal MEFs but could replicate to some extent in both KO MEF lines. The level of virus growth was inversely correlated with the amount of type I IFNs produced. These results suggest that PACT plays an important role in potentiating RIG-I function to produce type I IFNs in order to restrict arenavirus replication and that viral NP RNase activity is essential for optimal viral replication by suppressing PACT-induced RIG-I activation.IMPORTANCE We report here a new role of the nucleoproteins of arenaviruses that can block type I IFN production via their specific inhibition of the cellular protein sensors of virus infection (RIG-I and PACT). Our results suggest that PACT plays an important role in potentiating RIG-I function to produce type I IFNs in order to restrict arenavirus replication. This new knowledge can be exploited for the development of novel antiviral treatments and/or vaccines against some arenaviruses that can cause severe and lethal hemorrhagic fever diseases in humans.
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20
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Jiang M, Zhang S, Yang Z, Lin H, Zhu J, Liu L, Wang W, Liu S, Liu W, Ma Y, Zhang L, Cao X. Self-Recognition of an Inducible Host lncRNA by RIG-I Feedback Restricts Innate Immune Response. Cell 2018; 173:906-919.e13. [DOI: 10.1016/j.cell.2018.03.064] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 02/17/2018] [Accepted: 03/26/2018] [Indexed: 12/25/2022]
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21
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Lee W, Lee SH, Kim M, Moon JS, Kim GW, Jung HG, Kim IH, Oh JE, Jung HE, Lee HK, Ku KB, Ahn DG, Kim SJ, Kim KS, Oh JW. Vibrio vulnificus quorum-sensing molecule cyclo(Phe-Pro) inhibits RIG-I-mediated antiviral innate immunity. Nat Commun 2018; 9:1606. [PMID: 29686409 PMCID: PMC5913291 DOI: 10.1038/s41467-018-04075-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 04/03/2018] [Indexed: 02/06/2023] Open
Abstract
The recognition of pathogen-derived ligands by pattern recognition receptors activates the innate immune response, but the potential interaction of quorum-sensing (QS) signaling molecules with host anti-viral defenses remains largely unknown. Here we show that the Vibrio vulnificus QS molecule cyclo(Phe-Pro) (cFP) inhibits interferon (IFN)-β production by interfering with retinoic-acid-inducible gene-I (RIG-I) activation. Binding of cFP to the RIG-I 2CARD domain induces a conformational change in RIG-I, preventing the TRIM25-mediated ubiquitination to abrogate IFN production. cFP enhances susceptibility to hepatitis C virus (HCV), as well as Sendai and influenza viruses, each known to be sensed by RIG-I but did not affect the melanoma-differentiation-associated gene 5 (MDA5)-recognition of norovirus. Our results reveal an inter-kingdom network between bacteria, viruses and host that dysregulates host innate responses via a microbial quorum-sensing molecule modulating the response to viral infection.
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Affiliation(s)
- Wooseong Lee
- Department of Biotechnology, Yonsei University, Seoul, 03722, Korea
| | - Seung-Hoon Lee
- Department of Biotechnology, Yonsei University, Seoul, 03722, Korea
| | - Minwoo Kim
- Department of Biotechnology, Yonsei University, Seoul, 03722, Korea
| | - Jae-Su Moon
- Department of Biotechnology, Yonsei University, Seoul, 03722, Korea
| | - Geon-Woo Kim
- Department of Biotechnology, Yonsei University, Seoul, 03722, Korea
| | - Hae-Gwang Jung
- Department of Biotechnology, Yonsei University, Seoul, 03722, Korea
| | - In Hwang Kim
- Department of Life Science, Sogang University, Seoul, 04107, Korea
| | - Ji Eun Oh
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea
| | - Hi Eun Jung
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea
| | - Heung Kyu Lee
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea
| | - Keun Bon Ku
- Center for Convergent Research of Emerging Virus Infection, Korea Research Institute of Chemical Technology, Daejeon, 34114, Korea
| | - Dae-Gyun Ahn
- Center for Convergent Research of Emerging Virus Infection, Korea Research Institute of Chemical Technology, Daejeon, 34114, Korea
| | - Seong-Jun Kim
- Center for Convergent Research of Emerging Virus Infection, Korea Research Institute of Chemical Technology, Daejeon, 34114, Korea
| | - Kun-Soo Kim
- Department of Life Science, Sogang University, Seoul, 04107, Korea
| | - Jong-Won Oh
- Department of Biotechnology, Yonsei University, Seoul, 03722, Korea.
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22
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Royston L, Essaidi-Laziosi M, Pérez-Rodríguez FJ, Piuz I, Geiser J, Krause KH, Huang S, Constant S, Kaiser L, Garcin D, Tapparel C. Viral chimeras decrypt the role of enterovirus capsid proteins in viral tropism, acid sensitivity and optimal growth temperature. PLoS Pathog 2018; 14:e1006962. [PMID: 29630666 PMCID: PMC5908207 DOI: 10.1371/journal.ppat.1006962] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 04/19/2018] [Accepted: 03/08/2018] [Indexed: 11/19/2022] Open
Abstract
Despite their genetic similarities, enteric and respiratory enteroviruses (EVs) have highly heterogeneous biophysical properties and cause a vast diversity of human pathologies. In vitro differences include acid sensitivity, optimal growth temperature and tissue tropism, which reflect a preferential in vivo replication in the respiratory or gastrointestinal tract and are thus key determinants of EV virulence. To investigate the underlying cause of these differences, we generated chimeras at the capsid-level between EV-D68 (a respiratory EV) and EV-D94 (an enteric EV). Although some chimeras were nonfunctional, EV-D94 with both the capsid and 2A protease or the capsid only of EV-D68 were both viable. Using this latter construct, we performed several functional assays, which indicated that capsid proteins determine acid sensitivity and tropism in cell lines and in respiratory, intestinal and neural tissues. Additionally, capsid genes were shown to also participate in determining the optimal growth temperature, since EV-D94 temperature adaptation relied on single mutations in VP1, while constructs with EV-D68 capsid could not adapt to higher temperatures. Finally, we demonstrate that EV-D68 maintains residual binding-capacity after acid-treatment despite a loss of infectivity. In contrast, non-structural rather than capsid proteins modulate the innate immune response in tissues. These unique biophysical insights expose another layer in the phenotypic diversity of one of world's most prevalent pathogens and could aid target selection for vaccine or antiviral development.
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Affiliation(s)
- Léna Royston
- University of Geneva Faculty of Medicine, Department of Microbiology and Molecular Medicine, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Manel Essaidi-Laziosi
- University of Geneva Faculty of Medicine, Department of Microbiology and Molecular Medicine, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Francisco J. Pérez-Rodríguez
- University of Geneva Faculty of Medicine, Department of Microbiology and Molecular Medicine, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Isabelle Piuz
- University of Geneva Faculty of Medicine, Department of Microbiology and Molecular Medicine, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Johan Geiser
- University of Geneva Faculty of Medicine, Department of Microbiology and Molecular Medicine, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Karl-Heinz Krause
- University of Geneva Faculty of Medicine, Department of Pathology and Immunology, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Song Huang
- Epithelix Sàrl, 18 Chemin des Aulx, Geneva, Switzerland
| | | | - Laurent Kaiser
- Laboratory of Virology, Division of Infectious Diseases, University of Geneva Hospitals, 4 Rue Gabrielle Perret-Gentil, Geneva 14, Switzerland
| | - Dominique Garcin
- University of Geneva Faculty of Medicine, Department of Microbiology and Molecular Medicine, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Caroline Tapparel
- University of Geneva Faculty of Medicine, Department of Microbiology and Molecular Medicine, 1 Rue Michel-Servet, Geneva, Switzerland
- * E-mail:
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23
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Miyamoto M, Komuro A. PACT is required for MDA5-mediated immunoresponses triggered by Cardiovirus infection via interaction with LGP2. Biochem Biophys Res Commun 2017; 494:227-233. [PMID: 29032202 DOI: 10.1016/j.bbrc.2017.10.048] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 10/10/2017] [Indexed: 12/21/2022]
Abstract
Laboratory of genetics and physiology 2 (LGP2) and melanoma differentiation-associated gene 5 (MDA5) cooperatively detect viral RNA in the cytoplasm of Cardiovirus-infected cells and activate innate immune responses. Here, we evaluated whether the double-stranded RNA-binding protein PACT plays a role in this anti-viral response to further elucidate the mechanism. Immunoprecipitation experiments demonstrated that PACT interacts with LGP2 and that this interaction is enhanced by encephalomyocarditis virus (EMCV) infection. In vitro interaction analyses using purified recombinant proteins confirmed that the single-stranded Theiler's murine encephalitis virus genome enhanced the interaction between LGP2 and PACT. Small interfering RNA knockdown experiments further indicated that PACT is required for Cardiovirus-triggered interferon responses. To support this functional interaction with LGP2, overexpressed PACT was shown to enhance EMCV-triggered interferon promoter activity only when LGP2 and MDA5 were co-expressed but not when MDA5 is expressed alone. Together, our findings indicate a possible role of PACT in regulating the Cardiovirus-triggered immune responses mediated by MDA5 and LGP2, which opens the door to novel therapeutic strategies in interferon-related autoimmune diseases and cancer.
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Affiliation(s)
- Masahiko Miyamoto
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | - Akihiko Komuro
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan.
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24
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Uchikawa E, Lethier M, Malet H, Brunel J, Gerlier D, Cusack S. Structural Analysis of dsRNA Binding to Anti-viral Pattern Recognition Receptors LGP2 and MDA5. Mol Cell 2017; 62:586-602. [PMID: 27203181 PMCID: PMC4885022 DOI: 10.1016/j.molcel.2016.04.021] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 03/21/2016] [Accepted: 04/19/2016] [Indexed: 12/14/2022]
Abstract
RIG-I and MDA5 sense virus-derived short 5′ppp blunt-ended or long dsRNA, respectively, causing interferon production. Non-signaling LGP2 appears to positively and negatively regulate MDA5 and RIG-I signaling, respectively. Co-crystal structures of chicken (ch) LGP2 with dsRNA display a fully or semi-closed conformation depending on the presence or absence of nucleotide. LGP2 caps blunt, 3′ or 5′ overhang dsRNA ends with 1 bp longer overall footprint than RIG-I. Structures of 1:1 and 2:1 complexes of chMDA5 with short dsRNA reveal head-to-head packing rather than the polar head-to-tail orientation described for long filaments. chLGP2 and chMDA5 make filaments with a similar axial repeat, although less co-operatively for chLGP2. Overall, LGP2 resembles a chimera combining a MDA5-like helicase domain and RIG-I like CTD supporting both stem and end binding. Functionally, RNA binding is required for LGP2-mediated enhancement of MDA5 activation. We propose that LGP2 end-binding may promote nucleation of MDA5 oligomerization on dsRNA. chLPG2-dsRNA structures reveal RIG-I like end binding, but overhangs are possible chMDA5-dsRNA complex structures show head-to-head packing on short dsRNAs LGP2 also has MDA5-like behavior, coating dsRNA but with less cooperativity Both human and chicken LGP2 enhance MDA5 signaling in an RNA-dependent manner
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MESH Headings
- Adenosine Diphosphate/metabolism
- Adenosine Triphosphatases/chemistry
- Adenosine Triphosphatases/genetics
- Adenosine Triphosphatases/metabolism
- Adenosine Triphosphate/metabolism
- Animals
- Avian Proteins/chemistry
- Avian Proteins/genetics
- Avian Proteins/metabolism
- Binding Sites
- Cell Line
- Chickens
- DEAD Box Protein 58/chemistry
- DEAD Box Protein 58/genetics
- DEAD Box Protein 58/metabolism
- Humans
- Hydrolysis
- Interferon-Induced Helicase, IFIH1/chemistry
- Interferon-Induced Helicase, IFIH1/genetics
- Interferon-Induced Helicase, IFIH1/metabolism
- Models, Molecular
- Nucleic Acid Conformation
- Protein Binding
- Protein Interaction Domains and Motifs
- RNA, Double-Stranded/chemistry
- RNA, Double-Stranded/genetics
- RNA, Double-Stranded/metabolism
- RNA-Binding Proteins/chemistry
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Receptors, Pattern Recognition/chemistry
- Receptors, Pattern Recognition/genetics
- Receptors, Pattern Recognition/metabolism
- Structure-Activity Relationship
- Transfection
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Affiliation(s)
- Emiko Uchikawa
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France; University Grenoble Alpes, Centre National de la Recherche Scientifique, EMBL Unit of Virus Host-Cell Interactions, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Mathilde Lethier
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France; University Grenoble Alpes, Centre National de la Recherche Scientifique, EMBL Unit of Virus Host-Cell Interactions, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Hélène Malet
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France; University Grenoble Alpes, Centre National de la Recherche Scientifique, EMBL Unit of Virus Host-Cell Interactions, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Joanna Brunel
- CIRI, International Center for Infectiology Research, Université de Lyon, 69007 Lyon, France; Inserm, U1111, 69007 Lyon, France; CNRS, UMR5308, 69007 Lyon, France; Ecole Normale Supérieure de Lyon, 69007 Lyon, France; Université Lyon 1, Centre International de Recherche en Infectiologie, 69007 Lyon, France
| | - Denis Gerlier
- CIRI, International Center for Infectiology Research, Université de Lyon, 69007 Lyon, France; Inserm, U1111, 69007 Lyon, France; CNRS, UMR5308, 69007 Lyon, France; Ecole Normale Supérieure de Lyon, 69007 Lyon, France; Université Lyon 1, Centre International de Recherche en Infectiologie, 69007 Lyon, France
| | - Stephen Cusack
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France; University Grenoble Alpes, Centre National de la Recherche Scientifique, EMBL Unit of Virus Host-Cell Interactions, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France.
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25
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Abstract
RIG-I-like receptors (RLRs) are cytosolic innate immune sensors that detect pathogenic RNA and induce a systemic antiviral response. During the last decade, many studies focused on their molecular characterization and the identification of RNA agonists. Therefore, it became more and more clear that RLR activation needs to be carefully regulated, because constitutive signaling or detection of endogenous RNA through loss of specificity is detrimental. Here, we review the current understanding of RLR activation and selectivity. We specifically focus upon recent findings on the function of the helicase domain in discriminating between different RNAs, and whose malfunctioning causes serious autoimmune diseases.
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Affiliation(s)
- Charlotte Lässig
- From the Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität, 81377 Munich and
| | - Karl-Peter Hopfner
- From the Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität, 81377 Munich and
- the Center for Integrated Protein Sciences, 81377 Munich, Germany
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26
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Liu X, Yang C, Hu Y, Lei E, Lin X, Zhao L, Zou Z, Zhang A, Zhou H, Chen H, Qian P, Jin M. HIST1H1C Regulates Interferon-β and Inhibits Influenza Virus Replication by Interacting with IRF3. Front Immunol 2017; 8:350. [PMID: 28392790 PMCID: PMC5364133 DOI: 10.3389/fimmu.2017.00350] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 03/10/2017] [Indexed: 01/26/2023] Open
Abstract
Influenza virus NS2 is well known for its role in viral ribonucleoprotein nuclear export; however, its function has not been fully understood. A recent study showed that NS2 might interact with HIST1H1C (H1C, H1.2). Histones have been found to affect influenza virus replication, such as the H2A, H2B, H3, and H4, but H1 has not been detected. Here, we found that H1C interacts with NS2 via its C-terminal in the nucleus and that H1C affects influenza virus replication. The H1N1 influenza virus replicates better in H1C knockout A549 cells compared to wild-type A549 cells, primarily because of the regulation of H1C on interferon-β (IFN-β). Further studies showed that the H1C phosphorylation mutant (T146A) decreases IFN-β, while H1C methylation mutants (K34A, K187A) increases IFN-β by releasing the nucleosome and promoting IRF3 binding to the IFN-β promoter. Interestingly, NS2 interacts with H1C, which reduces H1C-IRF3 interaction and results in the inhibition of IFN-β enhanced by H1C. In summary, our study reveals a novel function of H1C to regulate IFN-β and uncovers an underlying mechanism, which suggests H1C plays a role in epigenetic regulation. Moreover, our results suggest a novel mechanism for the influenza virus to antagonize the innate immune response by NS2.
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Affiliation(s)
- Xiaokun Liu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University , Wuhan , China
| | - Cha Yang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University , Wuhan , China
| | - Yong Hu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China; Hubei Collaborative Innovation Center for Industrial Fermentation, Hubei University of Technology, Wuhan, China
| | - Erming Lei
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University , Wuhan , China
| | - Xian Lin
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University , Wuhan , China
| | - Lianzhong Zhao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University , Wuhan , China
| | - Zhong Zou
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University , Wuhan , China
| | - Anding Zhang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China; State Key Laboratory of Agricultural Microbiology, Key Laboratory of Agro-Microbiology Resources Development, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Hongbo Zhou
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China; State Key Laboratory of Agricultural Microbiology, Key Laboratory of Agro-Microbiology Resources Development, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China; State Key Laboratory of Agricultural Microbiology, Key Laboratory of Agro-Microbiology Resources Development, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Ping Qian
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China; State Key Laboratory of Agricultural Microbiology, Key Laboratory of Agro-Microbiology Resources Development, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Meilin Jin
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China; State Key Laboratory of Agricultural Microbiology, Key Laboratory of Agro-Microbiology Resources Development, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
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27
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Liu Y, Olagnier D, Lin R. Host and Viral Modulation of RIG-I-Mediated Antiviral Immunity. Front Immunol 2017; 7:662. [PMID: 28096803 PMCID: PMC5206486 DOI: 10.3389/fimmu.2016.00662] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 12/16/2016] [Indexed: 12/21/2022] Open
Abstract
Innate immunity is the first line of defense against invading pathogens. Rapid and efficient detection of pathogen-associated molecular patterns via pattern-recognition receptors is essential for the host to mount defensive and protective responses. Retinoic acid-inducible gene-I (RIG-I) is critical in triggering antiviral and inflammatory responses for the control of viral replication in response to cytoplasmic virus-specific RNA structures. Upon viral RNA recognition, RIG-I recruits the mitochondrial adaptor protein mitochondrial antiviral signaling protein, which leads to a signaling cascade that coordinates the induction of type I interferons (IFNs), as well as a large variety of antiviral interferon-stimulated genes. The RIG-I activation is tightly regulated via various posttranslational modifications for the prevention of aberrant innate immune signaling. By contrast, viruses have evolved mechanisms of evasion, such as sequestrating viral structures from RIG-I detections and targeting receptor or signaling molecules for degradation. These virus–host interactions have broadened our understanding of viral pathogenesis and provided insights into the function of the RIG-I pathway. In this review, we summarize the recent advances regarding RIG-I pathogen recognition and signaling transduction, cell-intrinsic control of RIG-I activation, and the viral antagonism of RIG-I signaling.
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Affiliation(s)
- Yiliu Liu
- Jewish General Hospital, Lady Davis Institute, McGill University, Montreal, QC, Canada; Division of Experimental Medicine, McGill University, Montreal, QC, Canada
| | - David Olagnier
- Jewish General Hospital, Lady Davis Institute, McGill University, Montreal, QC, Canada; Division of Experimental Medicine, McGill University, Montreal, QC, Canada
| | - Rongtuan Lin
- Jewish General Hospital, Lady Davis Institute, McGill University, Montreal, QC, Canada; Division of Experimental Medicine, McGill University, Montreal, QC, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
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28
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Zhao J, Zeng Y, Xu S, Chen J, Shen G, Yu C, Knipe D, Yuan W, Peng J, Xu W, Zhang C, Xia Z, Feng P. A Viral Deamidase Targets the Helicase Domain of RIG-I to Block RNA-Induced Activation. Cell Host Microbe 2016; 20:770-784. [PMID: 27866900 DOI: 10.1016/j.chom.2016.10.011] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 09/08/2016] [Accepted: 10/07/2016] [Indexed: 12/31/2022]
Abstract
RIG-I detects double-stranded RNA (dsRNA) to trigger antiviral cytokine production. Protein deamidation is emerging as a post-translational modification that chiefly regulates protein function. We report here that UL37 of herpes simplex virus 1 (HSV-1) is a protein deamidase that targets RIG-I to block RNA-induced activation. Mass spectrometry analysis identified two asparagine residues in the helicase 2i domain of RIG-I that were deamidated upon UL37 expression or HSV-1 infection. Deamidation rendered RIG-I unable to sense viral dsRNA, thus blocking its ability to trigger antiviral immune responses and restrict viral replication. Purified full-length UL37 and its carboxyl-terminal fragment were sufficient to deamidate RIG-I in vitro. Uncoupling RIG-I deamidation from HSV-1 infection, by engineering deamidation-resistant RIG-I or introducing deamidase-deficient UL37 into the HSV-1 genome, restored RIG-I activation and antiviral immune signaling. Our work identifies a viral deamidase and extends the paradigm of deamidation-mediated suppression of innate immunity by microbial pathogens.
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Affiliation(s)
- Jun Zhao
- Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center, University of Southern California, 1441 Eastlake Street, Los Angeles, CA 90033, USA
| | - Yi Zeng
- Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center, University of Southern California, 1441 Eastlake Street, Los Angeles, CA 90033, USA
| | - Simin Xu
- Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center, University of Southern California, 1441 Eastlake Street, Los Angeles, CA 90033, USA
| | - Jie Chen
- Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center, University of Southern California, 1441 Eastlake Street, Los Angeles, CA 90033, USA; Division of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Guobo Shen
- Department of Biological Structure, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Caiqun Yu
- Department of Chemistry, Dornsife College of Arts, Letters, and Sciences, University of Southern California, LJS 369, 840 Downey Way, Los Angeles, CA 90089, USA
| | - David Knipe
- Department of Microbiology and Molecular Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Weiming Yuan
- Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center, University of Southern California, 1441 Eastlake Street, Los Angeles, CA 90033, USA
| | - Jian Peng
- Division of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Wenqing Xu
- Department of Biological Structure, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Chao Zhang
- Department of Chemistry, Dornsife College of Arts, Letters, and Sciences, University of Southern California, LJS 369, 840 Downey Way, Los Angeles, CA 90089, USA
| | - Zanxian Xia
- State Key Laboratory of Medical Genetics and School of Life Sciences, Central South University, Changsha, Hunan 410008, China
| | - Pinghui Feng
- Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center, University of Southern California, 1441 Eastlake Street, Los Angeles, CA 90033, USA.
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29
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RNAs Containing Modified Nucleotides Fail To Trigger RIG-I Conformational Changes for Innate Immune Signaling. mBio 2016; 7:mBio.00833-16. [PMID: 27651356 PMCID: PMC5030355 DOI: 10.1128/mbio.00833-16] [Citation(s) in RCA: 158] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Invading pathogen nucleic acids are recognized and bound by cytoplasmic (retinoic acid-inducible gene I [RIG-I]-like) and membrane-bound (Toll-like) pattern recognition receptors to activate innate immune signaling. Modified nucleotides, when present in RNA molecules, diminish the magnitude of these signaling responses. However, mechanisms explaining the blunted signaling have not been elucidated. In this study, we used several independent biological assays, including inhibition of virus replication, RIG-I:RNA binding assays, and limited trypsin digestion of RIG-I:RNA complexes, to begin to understand how RNAs containing modified nucleotides avoid or suppress innate immune signaling. The experiments were based on a model innate immune activating RNA molecule, the polyU/UC RNA domain of hepatitis C virus, which was transcribed in vitro with canonical nucleotides or with one of eight modified nucleotides. The approach revealed signature assay responses associated with individual modified nucleotides or classes of modified nucleotides. For example, while both N-6-methyladenosine (m6A) and pseudouridine nucleotides correlate with diminished signaling, RNA containing m6A modifications bound RIG-I poorly, while RNA containing pseudouridine bound RIG-I with high affinity but failed to trigger the canonical RIG-I conformational changes associated with robust signaling. These data advance understanding of RNA-mediated innate immune signaling, with additional relevance for applying nucleotide modifications to RNA therapeutics. The innate immune system provides the first response to virus infections and must distinguish between host and pathogen nucleic acids to mount a protective immune response without activating autoimmune responses. While the presence of nucleotide modifications in RNA is known to correlate with diminished innate immune signaling, the underlying mechanisms have not been explored. The data reported here are important for defining mechanistic details to explain signaling suppression by RNAs containing modified nucleotides. The results suggest that RNAs containing modified nucleotides interrupt signaling at early steps of the RIG-I-like innate immune activation pathway and also that nucleotide modifications with similar chemical structures can be organized into classes that suppress or evade innate immune signaling steps. These data contribute to defining the molecular basis for innate immune signaling suppression by RNAs containing modified nucleotides. The results have important implications for designing therapeutic RNAs that evade innate immune detection.
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30
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Sohn J, Hur S. Filament assemblies in foreign nucleic acid sensors. Curr Opin Struct Biol 2016; 37:134-44. [PMID: 26859869 DOI: 10.1016/j.sbi.2016.01.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 01/20/2016] [Accepted: 01/21/2016] [Indexed: 12/24/2022]
Abstract
Helical filamentous assembly is ubiquitous in biology, but was only recently realized to be broadly employed in the innate immune system of vertebrates. Accumulating evidence suggests that the filamentous assemblies and helical oligomerization play important roles in detection of foreign nucleic acids and activation of the signaling pathways to produce antiviral and inflammatory mediators. In this review, we focus on the helical assemblies observed in the signaling pathways of RIG-I-like receptors (RLRs) and AIM2-like receptors (ALRs). We describe ligand-dependent oligomerization of receptor, receptor-dependent oligomerization of signaling adaptor molecules, and their functional implications and regulations.
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Affiliation(s)
- Jungsan Sohn
- Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Sun Hur
- Harvard Medical School, Boston, MA, USA.
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31
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Leung DW, Amarasinghe GK. When your cap matters: structural insights into self vs non-self recognition of 5' RNA by immunomodulatory host proteins. Curr Opin Struct Biol 2016; 36:133-41. [PMID: 26916433 PMCID: PMC5218996 DOI: 10.1016/j.sbi.2016.02.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 02/04/2016] [Indexed: 12/13/2022]
Abstract
Cytosolic recognition of viral RNA is important for host innate immune responses. Differential recognition of self vs non-self RNA is a considerable challenge as the inability to differentiate may trigger aberrant immune responses. Recent work identified the composition of the RNA 5', including the 5' cap and its methylation state, as an important determinant of recognition by the host. Recent studies have advanced our understanding of the modified 5' RNA recognition and viral antagonism of RNA receptors. Here, we will discuss RIG-I and IFIT proteins as examples of host proteins that detect dsRNA and ssRNA, respectively.
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Affiliation(s)
- Daisy W Leung
- Department of Pathology and Immunology, Washington University School of Medicine, Campus Box 8118, 660 South Euclid Avenue, St Louis, MO 63110, United States.
| | - Gaya K Amarasinghe
- Department of Pathology and Immunology, Washington University School of Medicine, Campus Box 8118, 660 South Euclid Avenue, St Louis, MO 63110, United States.
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32
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Ramanathan A, Devarkar SC, Jiang F, Miller MT, Khan AG, Marcotrigiano J, Patel SS. The autoinhibitory CARD2-Hel2i Interface of RIG-I governs RNA selection. Nucleic Acids Res 2016; 44:896-909. [PMID: 26612866 PMCID: PMC4737149 DOI: 10.1093/nar/gkv1299] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 10/30/2015] [Accepted: 11/05/2015] [Indexed: 12/24/2022] Open
Abstract
RIG-I (Retinoic Acid Inducible Gene-I) is a cytosolic innate immune receptor that detects atypical features in viral RNAs as foreign to initiate a Type I interferon signaling response. RIG-I is present in an autoinhibited state in the cytoplasm and activated by blunt-ended double-stranded (ds)RNAs carrying a 5' triphosphate (ppp) moiety. These features found in many pathogenic RNAs are absent in cellular RNAs due to post-transcriptional modifications of RNA ends. Although RIG-I is structurally well characterized, the mechanistic basis for RIG-I's remarkable ability to discriminate between cellular and pathogenic RNAs is not completely understood. We show that RIG-I's selectivity for blunt-ended 5'-ppp dsRNAs is ≈3000 times higher than non-blunt ended dsRNAs commonly found in cellular RNAs. Discrimination occurs at multiple stages and signaling RNAs have high affinity and ATPase turnover rate and thus a high katpase/Kd. We show that RIG-I uses its autoinhibitory CARD2-Hel2i (second CARD-helicase insertion domain) interface as a barrier to select against non-blunt ended dsRNAs. Accordingly, deletion of CARDs or point mutations in the CARD2-Hel2i interface decreases the selectivity from ≈3000 to 150 and 750, respectively. We propose that the CARD2-Hel2i interface is a 'gate' that prevents cellular RNAs from generating productive complexes that can signal.
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Affiliation(s)
- Anand Ramanathan
- Robert Wood Johnson Medical School, Department of Biochemistry and Molecular Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Swapnil C Devarkar
- Robert Wood Johnson Medical School, Department of Biochemistry and Molecular Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Fuguo Jiang
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Matthew T Miller
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Abdul G Khan
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Joseph Marcotrigiano
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Smita S Patel
- Robert Wood Johnson Medical School, Department of Biochemistry and Molecular Biology, Rutgers University, Piscataway, NJ 08854, USA
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33
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Anchisi S, Guerra J, Mottet-Osman G, Garcin D. Mismatches in the Influenza A Virus RNA Panhandle Prevent Retinoic Acid-Inducible Gene I (RIG-I) Sensing by Impairing RNA/RIG-I Complex Formation. J Virol 2016; 90:586-90. [PMID: 26446607 PMCID: PMC4702558 DOI: 10.1128/jvi.01671-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 10/05/2015] [Indexed: 11/20/2022] Open
Abstract
Influenza virus RNA (vRNA) promoter panhandle structures are believed to be sensed by retinoic acid-inducible gene I (RIG-I). The occurrence of mismatches in this double-stranded RNA structure raises questions about their effect on innate sensing. Our results suggest that mismatches in vRNA promoters decrease binding to RIG-I in vivo, affecting RNA/RIG-I complex formation and preventing RIG-I activation. These results can be inferred to apply to other viruses and suggest that mismatches may represent a general viral strategy to escape RIG-I sensing.
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Affiliation(s)
- Stéphanie Anchisi
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Jessica Guerra
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Geneviève Mottet-Osman
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Dominique Garcin
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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34
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Lässig C, Matheisl S, Sparrer KMJ, de Oliveira Mann CC, Moldt M, Patel JR, Goldeck M, Hartmann G, García-Sastre A, Hornung V, Conzelmann KK, Beckmann R, Hopfner KP. ATP hydrolysis by the viral RNA sensor RIG-I prevents unintentional recognition of self-RNA. eLife 2015; 4:e10859. [PMID: 26609812 PMCID: PMC4733034 DOI: 10.7554/elife.10859] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 11/25/2015] [Indexed: 12/24/2022] Open
Abstract
The cytosolic antiviral innate immune sensor RIG-I distinguishes 5' tri- or diphosphate containing viral double-stranded (ds) RNA from self-RNA by an incompletely understood mechanism that involves ATP hydrolysis by RIG-I's RNA translocase domain. Recently discovered mutations in ATPase motifs can lead to the multi-system disorder Singleton-Merten Syndrome (SMS) and increased interferon levels, suggesting misregulated signaling by RIG-I. Here we report that SMS mutations phenocopy a mutation that allows ATP binding but prevents hydrolysis. ATPase deficient RIG-I constitutively signals through endogenous RNA and co-purifies with self-RNA even from virus infected cells. Biochemical studies and cryo-electron microscopy identify a 60S ribosomal expansion segment as a dominant self-RNA that is stably bound by ATPase deficient RIG-I. ATP hydrolysis displaces wild-type RIG-I from this self-RNA but not from 5' triphosphate dsRNA. Our results indicate that ATP-hydrolysis prevents recognition of self-RNA and suggest that SMS mutations lead to unintentional signaling through prolonged RNA binding.
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Affiliation(s)
- Charlotte Lässig
- Gene Center, Department of Biochemistry, Ludwig Maximilian University of Munich, Munich, Germany
| | - Sarah Matheisl
- Gene Center, Department of Biochemistry, Ludwig Maximilian University of Munich, Munich, Germany
| | - Konstantin MJ Sparrer
- Max von Pettenkofer-Institute, Gene Center, Ludwig Maximilian University of Munich, Munich, Germany
| | | | - Manuela Moldt
- Gene Center, Department of Biochemistry, Ludwig Maximilian University of Munich, Munich, Germany
| | - Jenish R Patel
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, United States
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Marion Goldeck
- Institute for Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Gunther Hartmann
- Institute for Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, United States
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, United States
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Veit Hornung
- Institute of Molecular Medicine, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Karl-Klaus Conzelmann
- Max von Pettenkofer-Institute, Gene Center, Ludwig Maximilian University of Munich, Munich, Germany
| | - Roland Beckmann
- Gene Center, Department of Biochemistry, Ludwig Maximilian University of Munich, Munich, Germany
- Center for Integrated Protein Science Munich, Munich, Germany
| | - Karl-Peter Hopfner
- Gene Center, Department of Biochemistry, Ludwig Maximilian University of Munich, Munich, Germany
- Center for Integrated Protein Science Munich, Munich, Germany
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35
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Abstract
Retinoic-acid inducible gene I (RIG-I) is a major pattern recognition receptor of the innate immune system. RIG-I is a cytoplasmic RNA helicase that is able to bind virus-specific RNA structures. Activated RIG-I switches into a conformation that locks the ligand RNA and signals via the MAVS-IRF-3 axis, resulting in the upregulation of antiviral interferons. Recent evidence suggests that the binding of RIG-I to regulatory RNA structures of two major human pathogens, influenza A virus and hepatitis B virus, can inhibit viral replication independent of the subsequent signal transduction. Thus, RIG-I rides a two-pronged attack, with an early-hitting, direct inhibition via occupancy of viral regulatory RNA structures, and a delayed response via signaling and induction of interferons.
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Affiliation(s)
- Friedemann Weber
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, D-35392 Giessen, Germany.
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36
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Abstract
The innate immune sensor RIG-I recognizes viral RNA while avoiding unwanted activation by self RNA. In this issue of Immunity, Schuberth-Wagner et al. (2015) show that a histidine residue in the RNA binding pocket of RIG-I sterically excludes the cap1 structure of self RNA, thereby preventing downstream activation.
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37
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Xu J, Mercado-López X, Grier JT, Kim WK, Chun LF, Irvine EB, Del Toro Duany Y, Kell A, Hur S, Gale M, Raj A, López CB. Identification of a Natural Viral RNA Motif That Optimizes Sensing of Viral RNA by RIG-I. mBio 2015; 6:e01265-15. [PMID: 26443454 PMCID: PMC4611036 DOI: 10.1128/mbio.01265-15] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 09/11/2015] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED Stimulation of the antiviral response depends on the sensing of viral pathogen-associated molecular patterns (PAMPs) by specialized cellular proteins. During infection with RNA viruses, 5'-di- or -triphosphates accompanying specific single or double-stranded RNA motifs trigger signaling of intracellular RIG-I-like receptors (RLRs) and initiate the antiviral response. Although these molecular signatures are present during the replication of many viruses, it is unknown whether they are sufficient for strong activation of RLRs during infection. Immunostimulatory defective viral genomes (iDVGs) from Sendai virus (SeV) are among the most potent natural viral triggers of antiviral immunity. Here we describe an RNA motif (DVG(70-114)) that is essential for the potent immunostimulatory activity of 5'-triphosphate-containing SeV iDVGs. DVG(70-114) enhances viral sensing by the host cell independently of the long stretches of complementary RNA flanking the iDVGs, and it retains its stimulatory potential when transferred to otherwise inert viral RNA. In vitro analysis showed that DVG(70-114) augments the binding of RIG-I to viral RNA and promotes enhanced RIG-I polymerization, thereby facilitating the onset of the antiviral response. Together, our results define a new natural viral PAMP enhancer motif that promotes viral recognition by RLRs and confers potent immunostimulatory activity to viral RNA. IMPORTANCE A discrete group of molecular motifs, including 5'-triphosphates associated with double-stranded RNA, have been identified as essential for the triggering of antiviral immunity. Most RNA viruses expose these motifs during their replication; however, successful viruses normally evade immune recognition and replicate to high levels before detection, indicating that unknown factors drive antiviral immunity. DVGs from SeV are among the most potent natural viral stimuli of the antiviral response known to date. These studies define a new natural viral motif present in DVGs that maximizes viral recognition by the intracellular sensor RIG-I, allowing fast and strong antiviral responses even in the presence of viral-encoded immune antagonists. This motif can be harnessed to increase the immunostimulatory potential of otherwise inert viral RNAs and represents a novel immunostimulatory enhancer that could be used in the development of vaccine adjuvants and antivirals.
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Affiliation(s)
- Jie Xu
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Xiomara Mercado-López
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jennifer T Grier
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Won-keun Kim
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Lauren F Chun
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Edward B Irvine
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yoandris Del Toro Duany
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Alison Kell
- Department of Immunology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Sun Hur
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Michael Gale
- Department of Immunology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Arjun Raj
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Carolina B López
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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38
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Louber J, Brunel J, Uchikawa E, Cusack S, Gerlier D. Kinetic discrimination of self/non-self RNA by the ATPase activity of RIG-I and MDA5. BMC Biol 2015; 13:54. [PMID: 26215161 PMCID: PMC4517655 DOI: 10.1186/s12915-015-0166-9] [Citation(s) in RCA: 42] [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: 03/31/2015] [Accepted: 07/11/2015] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND The cytoplasmic RIG-like receptors are responsible for the early detection of viruses and other intracellular microbes by activating the innate immune response mediated by type I interferons (IFNs). RIG-I and MDA5 detect virus-specific RNA motifs with short 5'-tri/diphosphorylated, blunt-end double-stranded RNA (dsRNA) and >0.5-2 kb long dsRNA as canonical agonists, respectively. However, in vitro, they can bind to many RNA species, while in cells there is an activation threshold. As SF2 helicase/ATPase family members, ATP hydrolysis is dependent on co-operative RNA and ATP binding. Whereas simultaneous ATP and cognate RNA binding is sufficient to activate RIG-I by releasing autoinhibition of the signaling domains, the physiological role of the ATPase activity of RIG-I and MDA5 remains controversial. RESULTS A cross-analysis of a rationally designed panel of RNA binding and ATPase mutants and truncated receptors, using type I IFN promoter activation as readout, allows us to refine our understanding of the structure-function relationships of RIG-I and MDA5. RNA activation of RIG-I depends on multiple critical RNA binding sites in its helicase domain as confirmed by functional evidence using novel mutations. We found that RIG-I or MDA5 mutants with low ATP hydrolysis activity exhibit constitutive activity but this was fully reverted when associated with mutations preventing RNA binding to the helicase domain. We propose that the turnover kinetics of the ATPase domain enables the discrimination of self/non-self RNA by both RIG-I and MDA5. Non-cognate, possibly self, RNA binding would lead to fast ATP turnover and RNA disassociation and thus insufficient time for the caspase activation and recruitment domains (CARDs) to promote downstream signaling, whereas tighter cognate RNA binding provides a longer time window for downstream events to be engaged. CONCLUSIONS The exquisite fine-tuning of RIG-I and MDA5 RNA-dependent ATPase activity coupled to CARD release allows a robust IFN response from a minor subset of non-self RNAs within a sea of cellular self RNAs. This avoids the eventuality of deleterious autoimmunity effects as have been recently described to arise from natural gain-of-function alleles of RIG-I and MDA5.
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Affiliation(s)
- Jade Louber
- CIRI, International Center for Infectiology Research, Université de Lyon, Lyon, France.
- INSERM, U1111, Lyon, France.
- Ecole Normale Supérieure de Lyon, Lyon, France.
- Université Claude Bernard Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France.
- CNRS, UMR5308, Lyon, France.
| | - Joanna Brunel
- CIRI, International Center for Infectiology Research, Université de Lyon, Lyon, France.
- INSERM, U1111, Lyon, France.
- Ecole Normale Supérieure de Lyon, Lyon, France.
- Université Claude Bernard Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France.
- CNRS, UMR5308, Lyon, France.
| | - Emiko Uchikawa
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, BP 181, 38042, Grenoble, Cedex 9, France.
- Unit of Virus Host Cell Interactions, UJF-EMBL-CNRS, UMI 3265, 71 Avenue des Martyrs, BP 181, 38042, Grenoble, Cedex 9, France.
| | - Stephen Cusack
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, BP 181, 38042, Grenoble, Cedex 9, France.
- Unit of Virus Host Cell Interactions, UJF-EMBL-CNRS, UMI 3265, 71 Avenue des Martyrs, BP 181, 38042, Grenoble, Cedex 9, France.
| | - Denis Gerlier
- CIRI, International Center for Infectiology Research, Université de Lyon, Lyon, France.
- INSERM, U1111, Lyon, France.
- Ecole Normale Supérieure de Lyon, Lyon, France.
- Université Claude Bernard Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France.
- CNRS, UMR5308, Lyon, France.
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39
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Abstract
In this issue, He et al. (2015) show how herpes virus usurps a cellular metabolic enzyme to induce RIG-I deamidation and RNA-independent activation, likely to better prevent further innate immune responses.
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Affiliation(s)
- Daniel Kolakofsky
- Department of Microbiology and Molecular Medicine, University of Geneva, 1211 Geneva 4, Switzerland
| | - Dominique Garcin
- Department of Microbiology and Molecular Medicine, University of Geneva, 1211 Geneva 4, Switzerland.
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