1
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Rehwinkel J, Mehdipour P. ADAR1: from basic mechanisms to inhibitors. Trends Cell Biol 2024:S0962-8924(24)00120-X. [PMID: 39030076 DOI: 10.1016/j.tcb.2024.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 06/17/2024] [Accepted: 06/20/2024] [Indexed: 07/21/2024]
Abstract
Adenosine deaminase acting on RNA 1 (ADAR1) converts adenosine to inosine in double-stranded RNA (dsRNA) molecules, a process known as A-to-I editing. ADAR1 deficiency in humans and mice results in profound inflammatory diseases characterised by the spontaneous induction of innate immunity. In cells lacking ADAR1, unedited RNAs activate RNA sensors. These include melanoma differentiation-associated gene 5 (MDA5) that induces the expression of cytokines, particularly type I interferons (IFNs), protein kinase R (PKR), oligoadenylate synthase (OAS), and Z-DNA/RNA binding protein 1 (ZBP1). Immunogenic RNAs 'defused' by ADAR1 may include transcripts from repetitive elements and other long duplex RNAs. Here, we review these recent fundamental discoveries and discuss implications for human diseases. Some tumours depend on ADAR1 to escape immune surveillance, opening the possibility of unleashing anticancer therapies with ADAR1 inhibitors.
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Affiliation(s)
- Jan Rehwinkel
- Medical Research Council Translational Immune Discovery Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DS, UK.
| | - Parinaz Mehdipour
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, UK.
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2
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Hu SB, Li JB. RNA editing and immune control: from mechanism to therapy. Curr Opin Genet Dev 2024; 86:102195. [PMID: 38643591 PMCID: PMC11162905 DOI: 10.1016/j.gde.2024.102195] [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: 01/18/2024] [Revised: 04/02/2024] [Accepted: 04/02/2024] [Indexed: 04/23/2024]
Abstract
Adenosine-to-inosine RNA editing, catalyzed by the enzymes ADAR1 and ADAR2, stands as a pervasive RNA modification. A primary function of ADAR1-mediated RNA editing lies in labeling endogenous double-stranded RNAs (dsRNAs) as 'self', thereby averting their potential to activate innate immune responses. Recent findings have highlighted additional roles of ADAR1, independent of RNA editing, that are crucial for immune control. Here, we focus on recent progress in understanding ADAR1's RNA editing-dependent and -independent roles in immune control. We describe how ADAR1 regulates various dsRNA innate immune receptors through distinct mechanisms. Furthermore, we discuss the implications of ADAR1 and RNA editing in diseases, including autoimmune diseases and cancers.
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Affiliation(s)
- Shi-Bin Hu
- Department of Genetics, Stanford University, Stanford, CA 94305, USA.
| | - Jin Billy Li
- Department of Genetics, Stanford University, Stanford, CA 94305, USA.
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3
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Lee K, Ku J, Ku D, Kim Y. Inverted Alu repeats: friends or foes in the human transcriptome. Exp Mol Med 2024; 56:1250-1262. [PMID: 38871814 PMCID: PMC11263572 DOI: 10.1038/s12276-024-01177-3] [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: 10/09/2023] [Revised: 12/07/2023] [Accepted: 12/08/2023] [Indexed: 06/15/2024] Open
Abstract
Alu elements are highly abundant primate-specific short interspersed nuclear elements that account for ~10% of the human genome. Due to their preferential location in gene-rich regions, especially in introns and 3' UTRs, Alu elements can exert regulatory effects on the expression of both host and neighboring genes. When two Alu elements with inverse orientations are positioned in close proximity, their transcription results in the generation of distinct double-stranded RNAs (dsRNAs), known as inverted Alu repeats (IRAlus). IRAlus are key immunogenic self-dsRNAs and post-transcriptional cis-regulatory elements that play a role in circular RNA biogenesis, as well as RNA transport and stability. Recently, IRAlus dsRNAs have emerged as regulators of transcription and activators of Z-DNA-binding proteins. The formation and activity of IRAlus can be modulated through RNA editing and interactions with RNA-binding proteins, and misregulation of IRAlus has been implicated in several immune-associated disorders. In this review, we summarize the emerging functions of IRAlus dsRNAs, the regulatory mechanisms governing IRAlus activity, and their relevance in the pathogenesis of human diseases.
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Affiliation(s)
- Keonyong Lee
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Jayoung Ku
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Doyeong Ku
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Yoosik Kim
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
- Graduate School of Engineering Biology, KAIST, Daejeon, 34141, Republic of Korea.
- KAIST Institute for BioCentury (KIB), Daejeon, 34141, Republic of Korea.
- KAIST Institute for Health Science and Technology (KIHST), Daejeon, 34141, Republic of Korea.
- BioProcess Engineering Research Center and BioInformatics Research Center, KAIST, Daejeon, 34141, Republic of Korea.
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4
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Cai ZY, Wu P, Liang H, Xie YZ, Zhang BX, He CL, Yang CR, Li H, Mo W, Yang ZH. A ZBP1 isoform blocks ZBP1-mediated cell death. Cell Rep 2024; 43:114221. [PMID: 38748877 DOI: 10.1016/j.celrep.2024.114221] [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: 01/08/2024] [Revised: 02/10/2024] [Accepted: 04/25/2024] [Indexed: 06/01/2024] Open
Abstract
ZBP1 is an interferon (IFN)-induced nucleic acid (NA) sensor that senses unusual Z-form NA (Z-NA) to promote cell death and inflammation. However, the mechanisms that dampen ZBP1 activation to fine-tune inflammatory responses are unclear. Here, we characterize a short isoform of ZBP1 (referred to as ZBP1-S) as an intrinsic suppressor of the inflammatory signaling mediated by full-length ZBP1. Mechanistically, ZBP1-S depresses ZBP1-mediated cell death by competitive binding with Z-NA for Zα domains of ZBP1. Cells from mice (Ripk1D325A/D325A) with cleavage-resistant RIPK1-induced autoinflammatory (CRIA) syndrome are alive but sensitive to IFN-induced and ZBP1-dependent cell death. Intriguingly, Ripk1D325A/D325A cells die spontaneously when ZBP1-S is deleted, indicating that cell death driven by ZBP1 is under the control of ZBP1-S. Thus, our findings reveal that alternative splicing of Zbp1 represents autogenic inhibition for regulating ZBP1 signaling and indicate that uncoupling of Z-NA with ZBP1 could be an effective strategy against autoinflammations.
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Affiliation(s)
- Zhi-Yu Cai
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China; Department of Gastroenterology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Liangzhu Laboratory, Zhejiang University, Hangzhou 310012, China
| | - Puqi Wu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Hao Liang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Yu-Ze Xie
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Bo-Xin Zhang
- Department of Gastroenterology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Liangzhu Laboratory, Zhejiang University, Hangzhou 310012, China
| | - Cai-Ling He
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Cong-Rong Yang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Hongda Li
- Institute for Brain Science and Disease, Key Laboratory of Major Brain Disease and Aging Research (Ministry of Education), Chongqing Medical University, Chongqing 400016, China
| | - Wei Mo
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China; Department of Gastroenterology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Liangzhu Laboratory, Zhejiang University, Hangzhou 310012, China; Department of Immunology, School of Basic Medical Science, Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310012, China; Institute for Brain Science and Disease, Key Laboratory of Major Brain Disease and Aging Research (Ministry of Education), Chongqing Medical University, Chongqing 400016, China.
| | - Zhang-Hua Yang
- Department of Gastroenterology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Liangzhu Laboratory, Zhejiang University, Hangzhou 310012, China.
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5
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Huang Y, Jiang W, Zhou R. DAMP sensing and sterile inflammation: intracellular, intercellular and inter-organ pathways. Nat Rev Immunol 2024:10.1038/s41577-024-01027-3. [PMID: 38684933 DOI: 10.1038/s41577-024-01027-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2024] [Indexed: 05/02/2024]
Abstract
Damage-associated molecular patterns (DAMPs) are endogenous molecules that are released from host cells as a result of cell death or damage. The release of DAMPs in tissues is associated with loss of tissue homeostasis. Sensing of DAMPs by innate immune receptors triggers inflammation, which can be beneficial in initiating the processes that restore tissue homeostasis but can also drive inflammatory diseases. In recent years, the sensing of intracellular DAMPs has received extensive attention in the field of sterile inflammation. However, emerging studies have shown that DAMPs that originate from neighbouring cells, and even from distal tissues or organs, also mediate sterile inflammatory responses. This multi-level sensing of DAMPs is crucial for intercellular, trans-tissue and trans-organ communication. Here, we summarize how DAMP-sensing receptors detect DAMPs from intracellular, intercellular or distal tissue and organ sources to mediate sterile inflammation. We also discuss the possibility of targeting DAMPs or their corresponding receptors to treat inflammatory diseases.
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Affiliation(s)
- Yi Huang
- Key Laboratory of Immune Response and Immunotherapy, Institute of Health and Medicine, Hefei Comprehensive National Science Center, Hefei, China
| | - Wei Jiang
- Key Laboratory of Immune Response and Immunotherapy, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
| | - Rongbin Zhou
- Key Laboratory of Immune Response and Immunotherapy, Institute of Health and Medicine, Hefei Comprehensive National Science Center, Hefei, China.
- Key Laboratory of Immune Response and Immunotherapy, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
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6
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Ashley CN, Broni E, Miller WA. ADAR Family Proteins: A Structural Review. Curr Issues Mol Biol 2024; 46:3919-3945. [PMID: 38785511 PMCID: PMC11120146 DOI: 10.3390/cimb46050243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024] Open
Abstract
This review aims to highlight the structures of ADAR proteins that have been crucial in the discernment of their functions and are relevant to future therapeutic development. ADAR proteins can correct or diversify genetic information, underscoring their pivotal contribution to protein diversity and the sophistication of neuronal networks. ADAR proteins have numerous functions in RNA editing independent roles and through the mechanisms of A-I RNA editing that continue to be revealed. Provided is a detailed examination of the ADAR family members-ADAR1, ADAR2, and ADAR3-each characterized by distinct isoforms that offer both structural diversity and functional variability, significantly affecting RNA editing mechanisms and exhibiting tissue-specific regulatory patterns, highlighting their shared features, such as double-stranded RNA binding domains (dsRBD) and a catalytic deaminase domain (CDD). Moreover, it explores ADARs' extensive roles in immunity, RNA interference, and disease modulation, demonstrating their ambivalent nature in both the advancement and inhibition of diseases. Through this comprehensive analysis, the review seeks to underline the potential of targeting ADAR proteins in therapeutic strategies, urging continued investigation into their biological mechanisms and health implications.
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Affiliation(s)
- Carolyn N. Ashley
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA; (C.N.A.); (E.B.)
| | - Emmanuel Broni
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA; (C.N.A.); (E.B.)
| | - Whelton A. Miller
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA; (C.N.A.); (E.B.)
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
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7
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Jarmoskaite I, Li JB. Multifaceted roles of RNA editing enzyme ADAR1 in innate immunity. RNA (NEW YORK, N.Y.) 2024; 30:500-511. [PMID: 38531645 PMCID: PMC11019752 DOI: 10.1261/rna.079953.124] [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: 01/16/2024] [Accepted: 02/09/2024] [Indexed: 03/28/2024]
Abstract
Innate immunity must be tightly regulated to enable sensitive pathogen detection while averting autoimmunity triggered by pathogen-like host molecules. A hallmark of viral infection, double-stranded RNAs (dsRNAs) are also abundantly encoded in mammalian genomes, necessitating surveillance mechanisms to distinguish "self" from "nonself." ADAR1, an RNA editing enzyme, has emerged as an essential safeguard against dsRNA-induced autoimmunity. By converting adenosines to inosines (A-to-I) in long dsRNAs, ADAR1 covalently marks endogenous dsRNAs, thereby blocking the activation of the cytoplasmic dsRNA sensor MDA5. Moreover, beyond its editing function, ADAR1 binding to dsRNA impedes the activation of innate immune sensors PKR and ZBP1. Recent landmark studies underscore the utility of silencing ADAR1 for cancer immunotherapy, by exploiting the ADAR1-dependence developed by certain tumors to unleash an antitumor immune response. In this perspective, we summarize the genetic and mechanistic evidence for ADAR1's multipronged role in suppressing dsRNA-mediated autoimmunity and explore the evolving roles of ADAR1 as an immuno-oncology target.
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Affiliation(s)
- Inga Jarmoskaite
- Department of Genetics, Stanford University, Stanford, California 94305, USA
- AIRNA Corporation, Cambridge, Massachusetts 02142, USA
| | - Jin Billy Li
- Department of Genetics, Stanford University, Stanford, California 94305, USA
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8
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Helbrecht I, Heiter D, Yang W, Vincze T, Hanneman A, Lutz T, Ettwiller L, Bochtler M, Xu SY. Characterization of winged helix domain fusion endonucleases as N6-methyladenine-dependent type IV restriction systems. Front Microbiol 2024; 15:1286822. [PMID: 38655080 PMCID: PMC11037411 DOI: 10.3389/fmicb.2024.1286822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 02/08/2024] [Indexed: 04/26/2024] Open
Abstract
Winged helix (wH) domains, also termed winged helix-turn-helix (wHTH) domains, are widespread in all kingdoms of life and have diverse roles. In the context of DNA binding and DNA modification sensing, some eukaryotic wH domains are known as sensors of non-methylated CpG. In contrast, the prokaryotic wH domains in DpnI and HhiV4I act as sensors of adenine methylation in the 6mApT (N6-methyladenine, 6mA, or N6mA) context. DNA-binding modes and interactions with the probed dinucleotide are vastly different in the two cases. Here, we show that the role of the wH domain as a sensor of adenine methylation is widespread in prokaryotes. We present previously uncharacterized examples of PD-(D/E)XK-wH (FcyTI, Psp4BI), PUA-wH-HNH (HtuIII), wH-GIY-YIG (Ahi29725I, Apa233I), and PLD-wH (Aba4572I, CbaI) fusion endonucleases that sense adenine methylation in the Dam+ Gm6ATC sequence contexts. Representatives of the wH domain endonuclease fusion families with the exception of the PLD-wH family could be purified, and an in vitro preference for adenine methylation in the Dam context could be demonstrated. Like most other modification-dependent restriction endonucleases (MDREs, also called type IV restriction systems), the new fusion endonucleases except those in the PD-(D/E)XK-wH family cleave close to but outside the recognition sequence. Taken together, our data illustrate the widespread combinatorial use of prokaryotic wH domains as adenine methylation readers. Other potential 6mA sensors in modified DNA are also discussed.
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Affiliation(s)
- Igor Helbrecht
- New England Biolabs, Inc., Ipswich, MA, United States
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Daniel Heiter
- New England Biolabs, Inc., Ipswich, MA, United States
| | - Weiwei Yang
- New England Biolabs, Inc., Ipswich, MA, United States
| | - Tamas Vincze
- New England Biolabs, Inc., Ipswich, MA, United States
| | | | - Thomas Lutz
- New England Biolabs, Inc., Ipswich, MA, United States
| | | | - Matthias Bochtler
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- International Institute of Molecular and Cell Biology, Warsaw, Poland
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9
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Ma M, Jiang W, Zhou R. DAMPs and DAMP-sensing receptors in inflammation and diseases. Immunity 2024; 57:752-771. [PMID: 38599169 DOI: 10.1016/j.immuni.2024.03.002] [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: 12/18/2023] [Revised: 02/17/2024] [Accepted: 03/01/2024] [Indexed: 04/12/2024]
Abstract
Damage-associated molecular patterns (DAMPs) are endogenous danger molecules produced in cellular damage or stress, and they can activate the innate immune system. DAMPs contain multiple types of molecules, including nucleic acids, proteins, ions, glycans, and metabolites. Although these endogenous molecules do not trigger immune response under steady-state condition, they may undergo changes in distribution, physical or chemical property, or concentration upon cellular damage or stress, and then they become DAMPs that can be sensed by innate immune receptors to induce inflammatory response. Thus, DAMPs play an important role in inflammation and inflammatory diseases. In this review, we summarize the conversion of homeostatic molecules into DAMPs; the diverse nature and classification, cellular origin, and sensing of DAMPs; and their role in inflammation and related diseases. Furthermore, we discuss the clinical strategies to treat DAMP-associated diseases via targeting DAMP-sensing receptors.
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Affiliation(s)
- Ming Ma
- Key Laboratory of Immune Response and Immunotherapy, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, Anhui, China
| | - Wei Jiang
- Key Laboratory of Immune Response and Immunotherapy, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, Anhui, China
| | - Rongbin Zhou
- Key Laboratory of Immune Response and Immunotherapy, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, Anhui, China; Department of Geriatrics, Gerontology Institute of Anhui Province, The First Affiliated Hospital of University of Science and Technology of China, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China.
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10
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de Reuver R, Maelfait J. Novel insights into double-stranded RNA-mediated immunopathology. Nat Rev Immunol 2024; 24:235-249. [PMID: 37752355 DOI: 10.1038/s41577-023-00940-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2023] [Indexed: 09/28/2023]
Abstract
Recent progress in human and mouse genetics has transformed our understanding of the molecular mechanisms by which recognition of self double-stranded RNA (self-dsRNA) causes immunopathology. Novel mouse models recapitulate loss-of-function mutations in the RNA editing enzyme ADAR1 that are found in patients with Aicardi-Goutières syndrome (AGS) - a monogenic inflammatory disease associated with increased levels of type I interferon. Extensive analyses of the genotype-phenotype relationships in these mice have now firmly established a causal relationship between increased intracellular concentrations of endogenous immunostimulatory dsRNA and type I interferon-driven immunopathology. Activation of the dsRNA-specific immune sensor MDA5 perpetuates the overproduction of type I interferons, and chronic engagement of the interferon-inducible innate immune receptors PKR and ZBP1 by dsRNA drives immunopathology by activating an integrated stress response or by inducing excessive cell death. Biochemical and genetic data support a role for the p150 isoform of ADAR1 in the cytosol in suppressing the spontaneous, pathological response to self-dsRNA.
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Affiliation(s)
- Richard de Reuver
- VIB-UGent Center for Inflammation Research, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Jonathan Maelfait
- VIB-UGent Center for Inflammation Research, Ghent, Belgium.
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
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11
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Bhatt U, Cucchiarini A, Luo Y, Evans CW, Mergny JL, Iyer KS, Smith NM. Preferential formation of Z-RNA over intercalated motifs in long noncoding RNA. Genome Res 2024; 34:217-230. [PMID: 38355305 PMCID: PMC10984386 DOI: 10.1101/gr.278236.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 01/31/2024] [Indexed: 02/16/2024]
Abstract
Secondary structure is a principal determinant of lncRNA function, predominantly regarding scaffold formation and interfaces with target molecules. Noncanonical secondary structures that form in nucleic acids have known roles in regulating gene expression and include G-quadruplexes (G4s), intercalated motifs (iMs), and R-loops (RLs). In this paper, we used the computational tools G4-iM Grinder and QmRLFS-finder to predict the formation of each of these structures throughout the lncRNA transcriptome in comparison to protein-coding transcripts. The importance of the predicted structures in lncRNAs in biological contexts was assessed by combining our results with publicly available lncRNA tissue expression data followed by pathway analysis. The formation of predicted G4 (pG4) and iM (piM) structures in select lncRNA sequences was confirmed in vitro using biophysical experiments under near-physiological conditions. We find that the majority of the tested pG4s form highly stable G4 structures, and identify many previously unreported G4s in biologically important lncRNAs. In contrast, none of the piM sequences are able to form iM structures, consistent with the idea that RNA is unable to form stable iMs. Unexpectedly, these C-rich sequences instead form Z-RNA structures, which have not been previously observed in regions containing cytosine repeats and represent an interesting and underexplored target for protein-RNA interactions. Our results highlight the prevalence and potential structure-associated functions of noncanonical secondary structures in lncRNAs, and show G4 and Z-RNA structure formation in many lncRNA sequences for the first time, furthering the understanding of the structure-function relationship in lncRNAs.
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Affiliation(s)
- Uditi Bhatt
- School of Molecular Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Anne Cucchiarini
- Laboratoire d'Optique et Biosciences, École Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91120 Palaiseau, France
| | - Yu Luo
- Laboratoire d'Optique et Biosciences, École Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91120 Palaiseau, France
| | - Cameron W Evans
- School of Molecular Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Jean-Louis Mergny
- Laboratoire d'Optique et Biosciences, École Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91120 Palaiseau, France
| | - K Swaminathan Iyer
- School of Molecular Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Nicole M Smith
- School of Molecular Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia;
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12
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Zhang D, Zhu L, Gao Y, Wang Y, Li P. RNA editing enzymes: structure, biological functions and applications. Cell Biosci 2024; 14:34. [PMID: 38493171 PMCID: PMC10944622 DOI: 10.1186/s13578-024-01216-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Accepted: 03/06/2024] [Indexed: 03/18/2024] Open
Abstract
With the advancement of sequencing technologies and bioinformatics, over than 170 different RNA modifications have been identified. However, only a few of these modifications can lead to base pair changes, which are called RNA editing. RNA editing is a ubiquitous modification in mammalian transcriptomes and is an important co/posttranscriptional modification that plays a crucial role in various cellular processes. There are two main types of RNA editing events: adenosine to inosine (A-to-I) editing, catalyzed by ADARs on double-stranded RNA or ADATs on tRNA, and cytosine to uridine (C-to-U) editing catalyzed by APOBECs. This article provides an overview of the structure, function, and applications of RNA editing enzymes. We discuss the structural characteristics of three RNA editing enzyme families and their catalytic mechanisms in RNA editing. We also explain the biological role of RNA editing, particularly in innate immunity, cancer biogenesis, and antiviral activity. Additionally, this article describes RNA editing tools for manipulating RNA to correct disease-causing mutations, as well as the potential applications of RNA editing enzymes in the field of biotechnology and therapy.
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Affiliation(s)
- Dejiu Zhang
- Institute for Translational Medicine, College of Medicine, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China.
| | - Lei Zhu
- College of Basic Medical, Qingdao Binhai University, Qingdao, China
| | - Yanyan Gao
- Institute for Translational Medicine, College of Medicine, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Yin Wang
- Institute for Translational Medicine, College of Medicine, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Peifeng Li
- Institute for Translational Medicine, College of Medicine, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China.
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13
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Rivera M, Zhang H, Pham J, Isquith J, Zhou QJ, Balaian L, Sasik R, Enlund S, Mark A, Ma W, Holm F, Fisch KM, Kuo DJ, Jamieson C, Jiang Q. Malignant A-to-I RNA editing by ADAR1 drives T cell acute lymphoblastic leukemia relapse via attenuating dsRNA sensing. Cell Rep 2024; 43:113704. [PMID: 38265938 PMCID: PMC10962356 DOI: 10.1016/j.celrep.2024.113704] [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: 06/02/2023] [Revised: 10/24/2023] [Accepted: 01/09/2024] [Indexed: 01/26/2024] Open
Abstract
Leukemia-initiating cells (LICs) are regarded as the origin of leukemia relapse and therapeutic resistance. Identifying direct stemness determinants that fuel LIC self-renewal is critical for developing targeted approaches. Here, we show that the RNA-editing enzyme ADAR1 is a crucial stemness factor that promotes LIC self-renewal by attenuating aberrant double-stranded RNA (dsRNA) sensing. Elevated adenosine-to-inosine editing is a common attribute of relapsed T cell acute lymphoblastic leukemia (T-ALL) regardless of molecular subtype. Consequently, knockdown of ADAR1 severely inhibits LIC self-renewal capacity and prolongs survival in T-ALL patient-derived xenograft models. Mechanistically, ADAR1 directs hyper-editing of immunogenic dsRNA to avoid detection by the innate immune sensor melanoma differentiation-associated protein 5 (MDA5). Moreover, we uncover that the cell-intrinsic level of MDA5 dictates the dependency on the ADAR1-MDA5 axis in T-ALL. Collectively, our results show that ADAR1 functions as a self-renewal factor that limits the sensing of endogenous dsRNA. Thus, targeting ADAR1 presents an effective therapeutic strategy for eliminating T-ALL LICs.
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Affiliation(s)
- Maria Rivera
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Moores Cancer Center, La Jolla, CA 92037, USA
| | - Haoran Zhang
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Moores Cancer Center, La Jolla, CA 92037, USA
| | - Jessica Pham
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jane Isquith
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Qingchen Jenny Zhou
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Moores Cancer Center, La Jolla, CA 92037, USA
| | - Larisa Balaian
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Roman Sasik
- Center for Computational Biology & Bioinformatics (CCBB), University of California, San Diego, La Jolla, CA 92093-0681, USA
| | - Sabina Enlund
- Department of Women's and Children's Health, Division of Pediatric Oncology and Pediatric Surgery, Karolinska Institutet, Solna, Sweden
| | - Adam Mark
- Center for Computational Biology & Bioinformatics (CCBB), University of California, San Diego, La Jolla, CA 92093-0681, USA
| | - Wenxue Ma
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Frida Holm
- Department of Women's and Children's Health, Division of Pediatric Oncology and Pediatric Surgery, Karolinska Institutet, Solna, Sweden
| | - Kathleen M Fisch
- Center for Computational Biology & Bioinformatics (CCBB), University of California, San Diego, La Jolla, CA 92093-0681, USA; Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, San Diego, La Jolla, CA 92037, USA
| | - Dennis John Kuo
- Moores Cancer Center, La Jolla, CA 92037, USA; Division of Pediatric Hematology-Oncology, Rady Children's Hospital San Diego, University of California, San Diego, San Diego, CA 92123, USA
| | - Catriona Jamieson
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Moores Cancer Center, La Jolla, CA 92037, USA
| | - Qingfei Jiang
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Moores Cancer Center, La Jolla, CA 92037, USA.
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14
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Luan X, Wang L, Song G, Zhou W. Innate immune responses to RNA: sensing and signaling. Front Immunol 2024; 15:1287940. [PMID: 38343534 PMCID: PMC10854198 DOI: 10.3389/fimmu.2024.1287940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 01/11/2024] [Indexed: 02/15/2024] Open
Abstract
Nucleic acids are among the most essential PAMPs (pathogen-associated molecular patterns). Animals have evolved numerous sensors to recognize nucleic acids and trigger immune signaling against pathogen replication, cellular stress and cancer. Many sensor proteins (e.g., cGAS, AIM2, and TLR9) recognize the molecular signature of infection or stress and are responsible for the innate immune response to DNA. Remarkably, recent evidence demonstrates that cGAS-like receptors acquire the ability to sense RNA in some forms of life. Compared with the nucleic-acid sensing by cGAS, innate immune responses to RNA are based on various RNA sensors, including RIG-I, MDA5, ADAR1, TLR3/7/8, OAS1, PKR, NLRP1/6, and ZBP1, via a broad-spectrum signaling axis. Importantly, new advances have brought to light the potential clinical application of targeting these signaling pathways. Here, we highlight the latest discoveries in the field. We also summarize the activation and regulatory mechanisms of RNA-sensing signaling. In addition, we discuss how RNA sensing is tightly controlled in cells and why the disruption of immune homeostasis is linked to disease.
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Affiliation(s)
- Xiaohan Luan
- Shenzhen Key Laboratory of Biomolecular Assembling and Regulation, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Lei Wang
- Department of Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Guangji Song
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Wen Zhou
- Shenzhen Key Laboratory of Biomolecular Assembling and Regulation, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
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15
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Cottrell KA, Andrews RJ, Bass BL. The competitive landscape of the dsRNA world. Mol Cell 2024; 84:107-119. [PMID: 38118451 PMCID: PMC10843539 DOI: 10.1016/j.molcel.2023.11.033] [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: 10/16/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/22/2023]
Abstract
The ability to sense and respond to infection is essential for life. Viral infection produces double-stranded RNAs (dsRNAs) that are sensed by proteins that recognize the structure of dsRNA. This structure-based recognition of viral dsRNA allows dsRNA sensors to recognize infection by many viruses, but it comes at a cost-the dsRNA sensors cannot always distinguish between "self" and "nonself" dsRNAs. "Self" RNAs often contain dsRNA regions, and not surprisingly, mechanisms have evolved to prevent aberrant activation of dsRNA sensors by "self" RNA. Here, we review current knowledge about the life of endogenous dsRNAs in mammals-the biosynthesis and processing of dsRNAs, the proteins they encounter, and their ultimate degradation. We highlight mechanisms that evolved to prevent aberrant dsRNA sensor activation and the importance of competition in the regulation of dsRNA sensors and other dsRNA-binding proteins.
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Affiliation(s)
- Kyle A Cottrell
- Department of Biochemistry, Purdue University, West Lafayette, IN, USA.
| | - Ryan J Andrews
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Brenda L Bass
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA.
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16
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Li J, Tang M, Ke RX, Li PL, Sheng ZG, Zhu BZ. The anti-cancer drug candidate CBL0137 induced necroptosis via forming left-handed Z-DNA and its binding protein ZBP1 in liver cells. Toxicol Appl Pharmacol 2024; 482:116765. [PMID: 37995810 DOI: 10.1016/j.taap.2023.116765] [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: 03/10/2023] [Revised: 11/13/2023] [Accepted: 11/16/2023] [Indexed: 11/25/2023]
Abstract
CBL0137, a promising small molecular anti-cancer drug candidate, has been found to effectively induce apoptosis via activating p53 and suppressing nuclear factor-kappa B (NF-κB). However, it is still not clear whether CBL0137 can induce necroptosis in liver cancer; and if so, what is the underlying molecular mechanism. Here we found that CBL0137 could significantly induce left-handed double helix structure Z-DNA formation in HepG2 cells as shown by Z-DNA specific antibody assay, which was further confirmed by observing the expression of Z-DNA binding protein 1 (ZBP1) and adenosine deaminase acting on RNA 1 (ADAR1). Interestingly, we found that caspase inhibition significantly promoted CBL0137-induced necroptosis, which was further supported with the increase of the late apoptosis and necrosis assessed by the flow cytometry. Furthermore, we found that CBL0137 can also induce the expression of the three necroptosis-related proteins: receptor interacting serine/threonine kinase 1 (RIPK1), receptor interacting serine/threonine kinase 3 (RIPK3), and mixed lineage kinase domain-like (MLKL). Taken together, it was assumed that CBL0137-indued necroptosis in liver cells was due to induction of Z-DNA and ZBP1, which activated RIPK1/RIPK3/MLKL pathway. This represents the first report on the induction of the Z-DNA-mediated necroptosis by CBL0137 in the liver cancer cells, which should provide new perspectives for CBL0137 treatment of liver cancer.
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Affiliation(s)
- Jun Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, University of Chinese Academy of Sciences, The Chinese Academy of Sciences, Beijing 100085, PR China; College of Environment and Resources, University of Chinese Academy of Sciences, Beijing 101408, PR China
| | - Miao Tang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, University of Chinese Academy of Sciences, The Chinese Academy of Sciences, Beijing 100085, PR China; College of Environment and Resources, University of Chinese Academy of Sciences, Beijing 101408, PR China
| | - Ruo-Xian Ke
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, University of Chinese Academy of Sciences, The Chinese Academy of Sciences, Beijing 100085, PR China; College of Environment and Resources, University of Chinese Academy of Sciences, Beijing 101408, PR China
| | - Pei-Lin Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, University of Chinese Academy of Sciences, The Chinese Academy of Sciences, Beijing 100085, PR China; College of Environment and Resources, University of Chinese Academy of Sciences, Beijing 101408, PR China
| | - Zhi-Guo Sheng
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, University of Chinese Academy of Sciences, The Chinese Academy of Sciences, Beijing 100085, PR China; College of Environment and Resources, University of Chinese Academy of Sciences, Beijing 101408, PR China.
| | - Ben-Zhan Zhu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, University of Chinese Academy of Sciences, The Chinese Academy of Sciences, Beijing 100085, PR China; College of Environment and Resources, University of Chinese Academy of Sciences, Beijing 101408, PR China; Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA.
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17
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Weng S, Yang X, Yu N, Wang PC, Xiong S, Ruan H. Harnessing ADAR-Mediated Site-Specific RNA Editing in Immune-Related Disease: Prediction and Therapeutic Implications. Int J Mol Sci 2023; 25:351. [PMID: 38203521 PMCID: PMC10779106 DOI: 10.3390/ijms25010351] [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: 10/31/2023] [Revised: 12/15/2023] [Accepted: 12/23/2023] [Indexed: 01/12/2024] Open
Abstract
ADAR (Adenosine Deaminases Acting on RNA) proteins are a group of enzymes that play a vital role in RNA editing by converting adenosine to inosine in RNAs. This process is a frequent post-transcriptional event observed in metazoan transcripts. Recent studies indicate widespread dysregulation of ADAR-mediated RNA editing across many immune-related diseases, such as human cancer. We comprehensively review ADARs' function as pattern recognizers and their capability to contribute to mediating immune-related pathways. We also highlight the potential role of site-specific RNA editing in maintaining homeostasis and its relationship to various diseases, such as human cancers. More importantly, we summarize the latest cutting-edge computational approaches and data resources for predicting and analyzing RNA editing sites. Lastly, we cover the recent advancement in site-directed ADAR editing tool development. This review presents an up-to-date overview of ADAR-mediated RNA editing, how site-specific RNA editing could potentially impact disease pathology, and how they could be harnessed for therapeutic applications.
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Affiliation(s)
- Shenghui Weng
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, China; (S.W.); (P.-C.W.)
| | - Xinyi Yang
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, China; (S.W.); (P.-C.W.)
| | - Nannan Yu
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, China; (S.W.); (P.-C.W.)
| | - Peng-Cheng Wang
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, China; (S.W.); (P.-C.W.)
| | - Sidong Xiong
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, China; (S.W.); (P.-C.W.)
| | - Hang Ruan
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, China; (S.W.); (P.-C.W.)
- MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Medical College of Soochow University, Suzhou 215123, China
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18
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Yang T, Wang G, Zhang M, Hu X, Li Q, Yun F, Xing Y, Song X, Zhang H, Hu G, Qian Y. Triggering endogenous Z-RNA sensing for anti-tumor therapy through ZBP1-dependent necroptosis. Cell Rep 2023; 42:113377. [PMID: 37922310 DOI: 10.1016/j.celrep.2023.113377] [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: 01/13/2022] [Revised: 08/15/2023] [Accepted: 10/19/2023] [Indexed: 11/05/2023] Open
Abstract
ZBP1 senses viral Z-RNAs to induce necroptotic cell death to restrain viral infection. ZBP1 is also thought to recognize host cell-derived Z-RNAs to regulate organ development and tissue inflammation in mice. However, it remains unknown how the host-derived Z-RNAs are formed and how these endogenous Z-RNAs are sensed by ZBP1. Here, we report that oxidative stress strongly induces host cell endogenous Z-RNAs, and the Z-RNAs then localize to stress granules for direct sensing by ZBP1 to trigger necroptosis. Oxidative stress triggers dramatically increase Z-RNA levels in tumor cells, and the Z-RNAs then directly trigger tumor cell necroptosis through ZBP1. Localization of the induced Z-RNAs to stress granules is essential for ZBP1 sensing. Oxidative stress-induced Z-RNAs significantly promote tumor chemotherapy via ZBP1-driven necroptosis. Thus, our study identifies oxidative stress as a critical trigger for Z-RNA formation and demonstrates how Z-RNAs are directly sensed by ZBP1 to trigger anti-tumor necroptotic cell death.
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Affiliation(s)
- Tao Yang
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Guodong Wang
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Mingxiang Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Xiaohu Hu
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Qi Li
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Fenglin Yun
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yingying Xing
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xinyang Song
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Haibing Zhang
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Guohong Hu
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Youcun Qian
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China.
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19
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de Regt AK, Anand K, Ciupka K, Bender F, Gatterdam K, Putschli B, Fusshöller D, Hilbig D, Kirchhoff A, Hunkler C, Wolter S, Grünewald A, Wallerath C, Schuberth-Wagner C, Ludwig J, Paeschke K, Bartok E, Hagelueken G, Hartmann G, Zillinger T, Geyer M, Schlee M. A conserved isoleucine in the binding pocket of RIG-I controls immune tolerance to mitochondrial RNA. Nucleic Acids Res 2023; 51:11893-11910. [PMID: 37831086 PMCID: PMC10681732 DOI: 10.1093/nar/gkad835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 09/01/2023] [Accepted: 09/21/2023] [Indexed: 10/14/2023] Open
Abstract
RIG-I is a cytosolic receptor of viral RNA essential for the immune response to numerous RNA viruses. Accordingly, RIG-I must sensitively detect viral RNA yet tolerate abundant self-RNA species. The basic binding cleft and an aromatic amino acid of the RIG-I C-terminal domain(CTD) mediate high-affinity recognition of 5'triphosphorylated and 5'base-paired RNA(dsRNA). Here, we found that, while 5'unmodified hydroxyl(OH)-dsRNA demonstrated residual activation potential, 5'-monophosphate(5'p)-termini, present on most cellular RNAs, prevented RIG-I activation. Determination of CTD/dsRNA co-crystal structures and mutant activation studies revealed that the evolutionarily conserved I875 within the CTD sterically inhibits 5'p-dsRNA binding. RIG-I(I875A) was activated by both synthetic 5'p-dsRNA and endogenous long dsRNA within the polyA-rich fraction of total cellular RNA. RIG-I(I875A) specifically interacted with long, polyA-bearing, mitochondrial(mt) RNA, and depletion of mtRNA from total RNA abolished its activation. Altogether, our study demonstrates that avoidance of 5'p-RNA recognition is crucial to prevent mtRNA-triggered RIG-I-mediated autoinflammation.
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Affiliation(s)
- Ann Kristin de Regt
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Kanchan Anand
- Institute of Structural Biology, University Hospital Bonn, Bonn, Germany
| | - Katrin Ciupka
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Felix Bender
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Karl Gatterdam
- Institute of Structural Biology, University Hospital Bonn, Bonn, Germany
| | - Bastian Putschli
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - David Fusshöller
- Institute of Structural Biology, University Hospital Bonn, Bonn, Germany
| | - Daniel Hilbig
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Bonn, Germany
| | - Alexander Kirchhoff
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Charlotte Hunkler
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Steven Wolter
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Agathe Grünewald
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Christina Wallerath
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | | | - Janos Ludwig
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Katrin Paeschke
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Bonn, Germany
| | - Eva Bartok
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
- Institute of Experimental Haematology and Transfusion Medicine, University Hospital Bonn, Bonn, Germany
- Unit of Experimental Immunology, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Gregor Hagelueken
- Institute of Structural Biology, University Hospital Bonn, Bonn, Germany
| | - Gunther Hartmann
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Thomas Zillinger
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Matthias Geyer
- Institute of Structural Biology, University Hospital Bonn, Bonn, Germany
| | - Martin Schlee
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
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20
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Hu SB, Heraud-Farlow J, Sun T, Liang Z, Goradia A, Taylor S, Walkley CR, Li JB. ADAR1p150 prevents MDA5 and PKR activation via distinct mechanisms to avert fatal autoinflammation. Mol Cell 2023; 83:3869-3884.e7. [PMID: 37797622 DOI: 10.1016/j.molcel.2023.09.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 07/14/2023] [Accepted: 09/12/2023] [Indexed: 10/07/2023]
Abstract
Effective immunity requires the innate immune system to distinguish foreign nucleic acids from cellular ones. Cellular double-stranded RNAs (dsRNAs) are edited by the RNA-editing enzyme ADAR1 to evade being recognized as viral dsRNA by cytoplasmic dsRNA sensors, including MDA5 and PKR. The loss of ADAR1-mediated RNA editing of cellular dsRNA activates MDA5. Additional RNA-editing-independent functions of ADAR1 have been proposed, but a specific mechanism has not been delineated. We now demonstrate that the loss of ADAR1-mediated RNA editing specifically activates MDA5, whereas loss of the cytoplasmic ADAR1p150 isoform or its dsRNA-binding activity enabled PKR activation. Deleting both MDA5 and PKR resulted in complete rescue of the embryonic lethality of Adar1p150-/- mice to adulthood, contrasting with the limited or no rescue by removing MDA5 or PKR alone. Our findings demonstrate that MDA5 and PKR are the primary in vivo effectors of fatal autoinflammation following the loss of ADAR1p150.
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Affiliation(s)
- Shi-Bin Hu
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Jacki Heraud-Farlow
- St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia; Department of Medicine, Eastern Hill Precinct, Melbourne Medical School, University of Melbourne, Fitzroy, VIC 3065, Australia
| | - Tao Sun
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Zhen Liang
- St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia; Department of Medicine, Eastern Hill Precinct, Melbourne Medical School, University of Melbourne, Fitzroy, VIC 3065, Australia
| | - Ankita Goradia
- St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Scott Taylor
- St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Carl R Walkley
- St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia; Department of Medicine, Eastern Hill Precinct, Melbourne Medical School, University of Melbourne, Fitzroy, VIC 3065, Australia.
| | - Jin Billy Li
- Department of Genetics, Stanford University, Stanford, CA 94305, USA.
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21
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Pfeiffer LS, Stafforst T. Precision RNA base editing with engineered and endogenous effectors. Nat Biotechnol 2023; 41:1526-1542. [PMID: 37735261 DOI: 10.1038/s41587-023-01927-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 07/26/2023] [Indexed: 09/23/2023]
Abstract
RNA base editing refers to the rewriting of genetic information within an intact RNA molecule and serves various functions, such as evasion of the endogenous immune system and regulation of protein function. To achieve this, certain enzymes have been discovered in human cells that catalyze the conversion of one nucleobase into another. This natural process could be exploited to manipulate and recode any base in a target transcript. In contrast to DNA base editing, analogous changes introduced in RNA are not permanent or inheritable but rather allow reversible and doseable effects that appeal to various therapeutic applications. The current practice of RNA base editing involves the deamination of adenosines and cytidines, which are converted to inosines and uridines, respectively. In this Review, we summarize current site-directed RNA base-editing strategies and highlight recent achievements to improve editing efficiency, precision, codon-targeting scope and in vivo delivery into disease-relevant tissues. Besides engineered editing effectors, we focus on strategies to harness endogenous adenosine deaminases acting on RNA (ADAR) enzymes and discuss limitations and future perspectives to apply the tools in basic research and as a therapeutic modality. We expect the field to realize the first RNA base-editing drug soon, likely on a well-defined genetic disease. However, the long-term challenge will be to carve out the sweet spot of the technology where its unique ability is exploited to modulate signaling cues, metabolism or other clinically relevant processes in a safe and doseable manner.
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Affiliation(s)
- Laura S Pfeiffer
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Thorsten Stafforst
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany.
- Gene and RNA Therapy Center, Faculty of Medicine, University of Tübingen, Tübingen, Germany.
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22
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Sarkar SN, Harioudh MK, Shao L, Perez J, Ghosh A. The Many Faces of Oligoadenylate Synthetases. J Interferon Cytokine Res 2023; 43:487-494. [PMID: 37751211 PMCID: PMC10654648 DOI: 10.1089/jir.2023.0098] [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: 07/17/2023] [Accepted: 08/13/2023] [Indexed: 09/27/2023] Open
Abstract
2'-5' Oligoadenylate synthetases (OAS) are interferon-stimulated genes that are most well-known to protect hosts from viral infections. They are evolutionarily related to an ancient family of Nucleotidyltransferases, which are primarily involved in pathogen-sensing and innate immune response. Classical function of OAS proteins involves double-stranded RNA-stimulated polymerization of adenosine triphosphate in 2'-5' oligoadenylates (2-5A), which can activate the latent RNase (RNase L) to degrade RNA. However, accumulated evidence over the years have suggested alternative mode of antiviral function of several OAS family proteins. Furthermore, recent studies have connected some OAS proteins with wider function beyond viral infection. Here, we review some of the canonical and noncanonical functions of OAS proteins and their mechanisms.
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Affiliation(s)
- Saumendra N. Sarkar
- Cancer Virology Program, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Munesh K. Harioudh
- Cancer Virology Program, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Lulu Shao
- Cancer Virology Program, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Joseph Perez
- Cancer Virology Program, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Arundhati Ghosh
- Cancer Virology Program, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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23
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Jacobsen CS, Salvador P, Yung JF, Kragness S, Mendoza HG, Mandel G, Beal PA. Library Screening Reveals Sequence Motifs That Enable ADAR2 Editing at Recalcitrant Sites. ACS Chem Biol 2023; 18:2188-2199. [PMID: 37040436 PMCID: PMC10581013 DOI: 10.1021/acschembio.3c00107] [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] [Indexed: 04/13/2023]
Abstract
Adenosine deaminases acting on RNA (ADARs) catalyze the hydrolytic deamination of adenosine to inosine in duplex RNA. The inosine product preferentially base pairs with cytidine resulting in an effective A-to-G edit in RNA. ADAR editing can result in a recoding event alongside other alterations to RNA function. A consequence of ADARs' selective activity on duplex RNA is that guide RNAs (gRNAs) can be designed to target an adenosine of interest and promote a desired recoding event. One of ADAR's main limitations is its preference to edit adenosines with specific 5' and 3' nearest neighbor nucleotides (e.g., 5' U, 3' G). Current rational design approaches are well-suited for this ideal sequence context, but limited when applied to difficult-to-edit sites. Here we describe a strategy for the in vitro evaluation of very large libraries of ADAR substrates (En Masse Evaluation of RNA Guides, EMERGe). EMERGe allows for a comprehensive screening of ADAR substrate RNAs that complements current design approaches. We used this approach to identify sequence motifs for gRNAs that enable editing in otherwise difficult-to-edit target sites. A guide RNA bearing one of these sequence motifs enabled the cellular repair of a premature termination codon arising from mutation of the MECP2 gene associated with Rett Syndrome. EMERGe provides an advancement in screening that not only allows for novel gRNA design, but also furthers our understanding of ADARs' specific RNA-protein interactions.
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Affiliation(s)
- Casey S. Jacobsen
- Department of Chemistry, University of California, Davis, Davis, CA, USA, 95616
| | - Prince Salvador
- Department of Chemistry, University of California, Davis, Davis, CA, USA, 95616
| | - John F. Yung
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA, 97239
| | - Sabrina Kragness
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA, 97239
| | - Herra G. Mendoza
- Department of Chemistry, University of California, Davis, Davis, CA, USA, 95616
| | - Gail Mandel
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA, 97239
| | - Peter A. Beal
- Department of Chemistry, University of California, Davis, Davis, CA, USA, 95616
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24
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Datta R, Adamska JZ, Bhate A, Li JB. A-to-I RNA editing by ADAR and its therapeutic applications: From viral infections to cancer immunotherapy. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 15:e1817. [PMID: 37718249 PMCID: PMC10947335 DOI: 10.1002/wrna.1817] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/19/2023]
Abstract
ADAR deaminases catalyze adenosine-to-inosine (A-to-I) editing on double-stranded RNA (dsRNA) substrates that regulate an umbrella of biological processes. One of the two catalytically active ADAR enzymes, ADAR1, plays a major role in innate immune responses by suppression of RNA sensing pathways which are orchestrated through the ADAR1-dsRNA-MDA5 axis. Unedited immunogenic dsRNA substrates are potent ligands for the cellular sensor MDA5. Upon activation, MDA5 leads to the induction of interferons and expression of hundreds of interferon-stimulated genes with potent antiviral activity. In this way, ADAR1 acts as a gatekeeper of the RNA sensing pathway by striking a fine balance between innate antiviral responses and prevention of autoimmunity. Reduced editing of immunogenic dsRNA by ADAR1 is strongly linked to the development of common autoimmune and inflammatory diseases. In viral infections, ADAR1 exhibits both antiviral and proviral effects. This is modulated by both editing-dependent and editing-independent functions, such as PKR antagonism. Several A-to-I RNA editing events have been identified in viruses, including in the insidious viral pathogen, SARS-CoV-2 which regulates viral fitness and infectivity, and could play a role in shaping viral evolution. Furthermore, ADAR1 is an attractive target for immuno-oncology therapy. Overexpression of ADAR1 and increased dsRNA editing have been observed in several human cancers. Silencing ADAR1, especially in cancers that are refractory to immune checkpoint inhibitors, is a promising therapeutic strategy for cancer immunotherapy in conjunction with epigenetic therapy. The mechanistic understanding of dsRNA editing by ADAR1 and dsRNA sensing by MDA5 and PKR holds great potential for therapeutic applications. This article is categorized under: RNA Processing > RNA Editing and Modification RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Rohini Datta
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Julia Z Adamska
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Amruta Bhate
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Jin Billy Li
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
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25
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Zhong Y, Zhong X, Qiao L, Wu H, Liu C, Zhang T. Zα domain proteins mediate the immune response. Front Immunol 2023; 14:1241694. [PMID: 37771585 PMCID: PMC10523160 DOI: 10.3389/fimmu.2023.1241694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 08/23/2023] [Indexed: 09/30/2023] Open
Abstract
The Zα domain has a compact α/β architecture containing a three-helix bundle flanked on one side by a twisted antiparallel β sheet. This domain displays a specific affinity for double-stranded nucleic acids that adopt a left-handed helical conformation. Currently, only three Zα-domain proteins have been identified in eukaryotes, specifically ADAR1, ZBP1, and PKZ. ADAR1 is a double-stranded RNA (dsRNA) binding protein that catalyzes the conversion of adenosine residues to inosine, resulting in changes in RNA structure, function, and expression. In addition to its editing function, ADAR1 has been shown to play a role in antiviral defense, gene regulation, and cellular differentiation. Dysregulation of ADAR1 expression and activity has been associated with various disease states, including cancer, autoimmune disorders, and neurological disorders. As a sensing molecule, ZBP1 exhibits the ability to recognize nucleic acids with a left-handed conformation. ZBP1 harbors a RIP homotypic interaction motif (RHIM), composed of a highly charged surface region and a leucine-rich hydrophobic core, enabling the formation of homotypic interactions between proteins with similar structure. Upon activation, ZBP1 initiates a downstream signaling cascade leading to programmed cell death, a process mediated by RIPK3 via the RHIM motif. PKZ was identified in fish, and contains two Zα domains at the N-terminus. PKZ is essential for normal growth and development and may contribute to the regulation of immune system function in fish. Interestingly, some pathogenic microorganisms also encode Zα domain proteins, such as, Vaccinia virus and Cyprinid Herpesvirus. Zα domain proteins derived from pathogenic microorganisms have been demonstrated to be pivotal contributors in impeding the host immune response and promoting virus replication and spread. This review focuses on the mammalian Zα domain proteins: ADAR1 and ZBP1, and thoroughly elucidates their functions in the immune response.
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Affiliation(s)
- Yuhan Zhong
- Laboratory of Liver Transplantation, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Xiao Zhong
- Laboratory of Liver Transplantation, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Liangjun Qiao
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Hong Wu
- Laboratory of Liver Transplantation, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Chang Liu
- Division of Liver, Department of General Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Ting Zhang
- Laboratory of Liver Transplantation, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
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26
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Herbert A. Flipons and small RNAs accentuate the asymmetries of pervasive transcription by the reset and sequence-specific microcoding of promoter conformation. J Biol Chem 2023; 299:105140. [PMID: 37544644 PMCID: PMC10474125 DOI: 10.1016/j.jbc.2023.105140] [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: 05/11/2023] [Revised: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023] Open
Abstract
The role of alternate DNA conformations such as Z-DNA in the regulation of transcription is currently underappreciated. These structures are encoded by sequences called flipons, many of which are enriched in promoter and enhancer regions. Through a change in their conformation, flipons provide a tunable mechanism to mechanically reset promoters for the next round of transcription. They act as actuators that capture and release energy to ensure that the turnover of the proteins at promoters is optimized to cell state. Likewise, the single-stranded DNA formed as flipons cycle facilitates the docking of RNAs that are able to microcode promoter conformations and canalize the pervasive transcription commonly observed in metazoan genomes. The strand-specific nature of the interaction between RNA and DNA likely accounts for the known asymmetry of epigenetic marks present on the histone tetramers that pair to form nucleosomes. The role of these supercoil-dependent processes in promoter choice and transcriptional interference is reviewed. The evolutionary implications are examined: the resilience and canalization of flipon-dependent gene regulation is contrasted with the rapid adaptation enabled by the spread of flipon repeats throughout the genome. Overall, the current findings underscore the important role of flipons in modulating the readout of genetic information and how little we know about their biology.
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Affiliation(s)
- Alan Herbert
- Discovery Division, InsideOutBio, Charlestown, Massachusetts, USA.
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27
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Lamichhane PP, Samir P. Cellular Stress: Modulator of Regulated Cell Death. BIOLOGY 2023; 12:1172. [PMID: 37759572 PMCID: PMC10525759 DOI: 10.3390/biology12091172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/22/2023] [Accepted: 08/22/2023] [Indexed: 09/29/2023]
Abstract
Cellular stress response activates a complex program of an adaptive response called integrated stress response (ISR) that can allow a cell to survive in the presence of stressors. ISR reprograms gene expression to increase the transcription and translation of stress response genes while repressing the translation of most proteins to reduce the metabolic burden. In some cases, ISR activation can lead to the assembly of a cytoplasmic membraneless compartment called stress granules (SGs). ISR and SGs can inhibit apoptosis, pyroptosis, and necroptosis, suggesting that they guard against uncontrolled regulated cell death (RCD) to promote organismal homeostasis. However, ISR and SGs also allow cancer cells to survive in stressful environments, including hypoxia and during chemotherapy. Therefore, there is a great need to understand the molecular mechanism of the crosstalk between ISR and RCD. This is an active area of research and is expected to be relevant to a range of human diseases. In this review, we provided an overview of the interplay between different cellular stress responses and RCD pathways and their modulation in health and disease.
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Affiliation(s)
| | - Parimal Samir
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
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28
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DeAntoneo C, Herbert A, Balachandran S. Z-form nucleic acid-binding protein 1 (ZBP1) as a sensor of viral and cellular Z-RNAs: walking the razor's edge. Curr Opin Immunol 2023; 83:102347. [PMID: 37276820 PMCID: PMC10526625 DOI: 10.1016/j.coi.2023.102347] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/01/2023] [Accepted: 05/02/2023] [Indexed: 06/07/2023]
Abstract
Z-form nucleic acid-binding protein 1 (ZBP1) detects viral Z-form RNAs (Z-RNAs), activates receptor-interacting protein kinase 3, and triggers cell death during both RNA and DNA virus infections. Such cell death promotes virus clearance by eliminating infected cells and galvanizing antiviral immunity, and is thus often targeted for evasion by virus-encoded suppressors. Recent evidence demonstrates that ZBP1 can also be activated by cellular Z-RNAs transcribed from endogenous retroelements within mammalian genomes. These cellular Z-RNAs, if not edited and neutralized by adenosine deaminase RNA-specific 1, trigger ZBP1-dependent cell death and inflammation, which may drive disease in Aicardi-Goutière's syndrome and related interferonopathies. Thus, while well-controlled activation of ZBP1 by viral Z-RNAs during infections is beneficial, the same pathway can have harmful consequences when inappropriately triggered by cellular Z-RNAs in other disease settings.
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Affiliation(s)
- Carly DeAntoneo
- Drexel University College of Medicine, 2900 W. Queen Lane, Philadelphia, PA 19129, USA; Center for Immunology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Alan Herbert
- InsideOutBio, 42 8th Street, Charlestown, MA, USA
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29
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Guo X, Liu S, Sheng Y, Zenati M, Billiar T, Herbert A, Wang Q. ADAR1 Zα domain P195A mutation activates the MDA5-dependent RNA-sensing signaling pathway in brain without decreasing overall RNA editing. Cell Rep 2023; 42:112733. [PMID: 37421629 PMCID: PMC10691306 DOI: 10.1016/j.celrep.2023.112733] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 05/03/2023] [Accepted: 06/16/2023] [Indexed: 07/10/2023] Open
Abstract
Variants of the RNA-editing enzyme ADAR1 cause Aicardi-Goutières syndrome (AGS), in which severe inflammation occurs in the brain due to innate immune activation. Here, we analyze the RNA-editing status and innate immune activation in an AGS mouse model that carries the Adar P195A mutation in the N terminus of the ADAR1 p150 isoform, the equivalent of the P193A human Zα variant causal for disease. This mutation alone can cause interferon-stimulated gene (ISG) expression in the brain, especially in the periventricular areas, reflecting the pathologic feature of AGS. However, in these mice, ISG expression does not correlate with an overall decrease in RNA editing. Rather, the enhanced ISG expression in the brain due to the P195A mutant is dose dependent. Our findings indicate that ADAR1 can regulate innate immune responses through Z-RNA binding without changing overall RNA editing.
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Affiliation(s)
- Xinfeng Guo
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Silvia Liu
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Yi Sheng
- Magee-Women's Research Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Mazen Zenati
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Timothy Billiar
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | | | - Qingde Wang
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; VA Pittsburgh Healthcare System, Pittsburgh, PA 15240, USA.
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30
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Rivera M, Zhang H, Pham J, Isquith J, Zhou QJ, Sasik R, Mark A, Ma W, Holm F, Fisch KM, Kuo DJ, Jamieson C, Jiang Q. Malignant A-to-I RNA editing by ADAR1 drives T-cell acute lymphoblastic leukemia relapse via attenuating dsRNA sensing. RESEARCH SQUARE 2023:rs.3.rs-2444524. [PMID: 37398458 PMCID: PMC10312963 DOI: 10.21203/rs.3.rs-2444524/v2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Leukemia initiating cells (LICs) are regarded as the origin of leukemia relapse and therapeutic resistance. Identifying direct stemness determinants that fuel LIC self-renewal is critical for developing targeted approaches to eliminate LICs and prevent relapse. Here, we show that the RNA editing enzyme ADAR1 is a crucial stemness factor that promotes LIC self-renewal by attenuating aberrant double-stranded RNA (dsRNA) sensing. Elevated adenosine-to-inosine (A-to-I) editing is a common attribute of relapsed T-ALL regardless of molecular subtypes. Consequently, knockdown of ADAR1 severely inhibits LIC self-renewal capacity and prolongs survival in T-ALL PDX models. Mechanistically, ADAR1 directs hyper-editing of immunogenic dsRNA and retains unedited nuclear dsRNA to avoid detection by the innate immune sensor MDA5. Moreover, we uncovered that the cell intrinsic level of MDA5 dictates the dependency on ADAR1-MDA5 axis in T-ALL. Collectively, our results show that ADAR1 functions as a self-renewal factor that limits the sensing of endogenous dsRNA. Thus, targeting ADAR1 presents a safe and effective therapeutic strategy for eliminating T-ALL LICs.
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Affiliation(s)
- Maria Rivera
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Moores Cancer Center, La Jolla, CA 92037, USA
| | - Haoran Zhang
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Moores Cancer Center, La Jolla, CA 92037, USA
| | - Jessica Pham
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Jane Isquith
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Qingchen Jenny Zhou
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Moores Cancer Center, La Jolla, CA 92037, USA
| | - Roman Sasik
- Center for Computational Biology & Bioinformatics (CCBB), University of California, San Diego, La Jolla, 92093-0681
| | - Adam Mark
- Center for Computational Biology & Bioinformatics (CCBB), University of California, San Diego, La Jolla, 92093-0681
| | - Wenxue Ma
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Frida Holm
- Department of Women’s and Children’s Health, Division of Pediatric Oncology and Surgery, Karolinska Institutet, Sweden
| | - Kathleen M Fisch
- Center for Computational Biology & Bioinformatics (CCBB), University of California, San Diego, La Jolla, 92093-0681
- Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, San Diego, La Jolla, CA
| | - Dennis John Kuo
- Moores Cancer Center, La Jolla, CA 92037, USA
- Division of Pediatric Hematology-Oncology, Rady Children’s Hospital San Diego, University of California, San Diego, CA
| | - Catriona Jamieson
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Moores Cancer Center, La Jolla, CA 92037, USA
| | - Qingfei Jiang
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Moores Cancer Center, La Jolla, CA 92037, USA
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31
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Mendez Ruiz S, Chalk AM, Goradia A, Heraud-Farlow J, Walkley C. Over-expression of ADAR1 in mice does not initiate or accelerate cancer formation in vivo. NAR Cancer 2023; 5:zcad023. [PMID: 37275274 PMCID: PMC10233902 DOI: 10.1093/narcan/zcad023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/27/2023] [Accepted: 05/16/2023] [Indexed: 06/07/2023] Open
Abstract
Adenosine to inosine editing (A-to-I) in regions of double stranded RNA (dsRNA) is mediated by adenosine deaminase acting on RNA 1 (ADAR1) or ADAR2. ADAR1 and A-to-I editing levels are increased in many human cancers. Inhibition of ADAR1 has emerged as a high priority oncology target, however, whether ADAR1 overexpression enables cancer initiation or progression has not been directly tested. We established a series of in vivo models to allow overexpression of full-length ADAR1, or its individual isoforms, to test if increased ADAR1 expression was oncogenic. Widespread over-expression of ADAR1 or the p110 or p150 isoforms individually as sole lesions was well tolerated and did not result in cancer initiation. Therefore, ADAR1 overexpression alone is not sufficient to initiate cancer. We demonstrate that endogenous ADAR1 and A-to-I editing increased upon immortalization in murine cells, consistent with the observations from human cancers. We tested if ADAR1 over-expression could co-operate with cancer initiated by loss of tumour suppressors using a model of osteosarcoma. We did not see a disease potentiating or modifying effect of overexpressing ADAR1 or its isoforms in the models assessed. We conclude that increased ADAR1 expression and A-to-I editing in cancers is most likely a consequence of tumor formation.
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Affiliation(s)
- Shannon Mendez Ruiz
- St Vincent's Institute of Medical Research, Fitzroy, Victoria 3065, Australia
- Department of Medicine, Eastern Hill Precinct, Melbourne Medical School, University of Melbourne, Fitzroy, Victoria 3065, Australia
| | - Alistair M Chalk
- St Vincent's Institute of Medical Research, Fitzroy, Victoria 3065, Australia
- Department of Medicine, Eastern Hill Precinct, Melbourne Medical School, University of Melbourne, Fitzroy, Victoria 3065, Australia
| | - Ankita Goradia
- St Vincent's Institute of Medical Research, Fitzroy, Victoria 3065, Australia
| | | | - Carl R Walkley
- To whom correspondence should be addressed. Tel: +61 3 9231 2480;
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32
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Straub S, Sampaio NG. Activation of cytosolic RNA sensors by endogenous ligands: roles in disease pathogenesis. Front Immunol 2023; 14:1092790. [PMID: 37292201 PMCID: PMC10244536 DOI: 10.3389/fimmu.2023.1092790] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 05/15/2023] [Indexed: 06/10/2023] Open
Abstract
Early detection of infection is a central and critical component of our innate immune system. Mammalian cells have developed specialized receptors that detect RNA with unusual structures or of foreign origin - a hallmark of many virus infections. Activation of these receptors induces inflammatory responses and an antiviral state. However, it is increasingly appreciated that these RNA sensors can also be activated in the absence of infection, and that this 'self-activation' can be pathogenic and promote disease. Here, we review recent discoveries in sterile activation of the cytosolic innate immune receptors that bind RNA. We focus on new aspects of endogenous ligand recognition uncovered in these studies, and their roles in disease pathogenesis.
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Affiliation(s)
- Sarah Straub
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular and Translational Sciences, School of Clinical Sciences, Monash University, Clayton, VIC, Australia
| | - Natalia G. Sampaio
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular and Translational Sciences, School of Clinical Sciences, Monash University, Clayton, VIC, Australia
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33
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Kleinova R, Rajendra V, Leuchtenberger AF, Lo Giudice C, Vesely C, Kapoor U, Tanzer A, Derdak S, Picardi E, Jantsch MF. The ADAR1 editome reveals drivers of editing-specificity for ADAR1-isoforms. Nucleic Acids Res 2023; 51:4191-4207. [PMID: 37026479 PMCID: PMC10201426 DOI: 10.1093/nar/gkad265] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 03/10/2023] [Accepted: 04/06/2023] [Indexed: 04/08/2023] Open
Abstract
Adenosine deaminase acting on RNA ADAR1 promotes A-to-I conversion in double-stranded and structured RNAs. ADAR1 has two isoforms transcribed from different promoters: cytoplasmic ADAR1p150 is interferon-inducible while ADAR1p110 is constitutively expressed and primarily localized in the nucleus. Mutations in ADAR1 cause Aicardi - Goutières syndrome (AGS), a severe autoinflammatory disease associated with aberrant IFN production. In mice, deletion of ADAR1 or the p150 isoform leads to embryonic lethality driven by overexpression of interferon-stimulated genes. This phenotype is rescued by deletion of the cytoplasmic dsRNA-sensor MDA5 indicating that the p150 isoform is indispensable and cannot be rescued by ADAR1p110. Nevertheless, editing sites uniquely targeted by ADAR1p150 remain elusive. Here, by transfection of ADAR1 isoforms into ADAR-less mouse cells we detect isoform-specific editing patterns. Using mutated ADAR variants, we test how intracellular localization and the presence of a Z-DNA binding domain-α affect editing preferences. These data show that ZBDα only minimally contributes to p150 editing-specificity while isoform-specific editing is primarily directed by the intracellular localization of ADAR1 isoforms. Our study is complemented by RIP-seq on human cells ectopically expressing tagged-ADAR1 isoforms. Both datasets reveal enrichment of intronic editing and binding by ADAR1p110 while ADAR1p150 preferentially binds and edits 3'UTRs.
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Affiliation(s)
- Renata Kleinova
- Center for Anatomy and Cell Biology, Division of Cell and Developmental Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
| | - Vinod Rajendra
- Center for Anatomy and Cell Biology, Division of Cell and Developmental Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
| | - Alina F Leuchtenberger
- Center for Integrative Bioinformatics Vienna (CIBIV) Max Perutz Labs, University of Vienna and Medical University of Vienna, Campus Vienna Biocenter 5, A-1030 Vienna, Austria
| | - Claudio Lo Giudice
- Department of Bioscience, Biotechnology and Biopharmaceutics, University of Bari Aldo Moro, University Campus “Ernesto Quagliariello”, Via Orabona 4, Bari, Italy
| | - Cornelia Vesely
- Center for Anatomy and Cell Biology, Division of Cell and Developmental Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
| | - Utkarsh Kapoor
- Center for Anatomy and Cell Biology, Division of Cell and Developmental Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
| | - Andrea Tanzer
- Center for Anatomy and Cell Biology, Division of Cell and Developmental Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
| | - Sophia Derdak
- Core Facilities Medical University of Vienna, Spitalgasse 23, A-1090 Vienna, Austria
| | - Ernesto Picardi
- Department of Bioscience, Biotechnology and Biopharmaceutics, University of Bari Aldo Moro, University Campus “Ernesto Quagliariello”, Via Orabona 4, Bari, Italy
- Institute of Biomembranes and Bioenergetics (IBBE), National Research Council (CNR), Via Amendola 122, Bari, Italy
| | - Michael F Jantsch
- Center for Anatomy and Cell Biology, Division of Cell and Developmental Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
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Sun S, Hong J, You E, Tsanov KM, Chacon-Barahona J, Gioacchino AD, Hoyos D, Li H, Jiang H, Ly H, Marhon S, Murali R, Chanda P, Karacay A, Vabret N, De Carvalho DD, LaCava J, Lowe SW, Ting DT, Iacobuzio-Donahue CA, Solovyov A, Greenbaum BD. Cancer cells co-evolve with retrotransposons to mitigate viral mimicry. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.19.541456. [PMID: 37292765 PMCID: PMC10245669 DOI: 10.1101/2023.05.19.541456] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Overexpression of repetitive elements is an emerging hallmark of human cancers 1 . Diverse repeats can mimic viruses by replicating within the cancer genome through retrotransposition, or presenting pathogen-associated molecular patterns (PAMPs) to the pattern recognition receptors (PRRs) of the innate immune system 2-5 . Yet, how specific repeats affect tumor evolution and shape the tumor immune microenvironment (TME) in a pro- or anti-tumorigenic manner remains poorly defined. Here, we integrate whole genome and total transcriptome data from a unique autopsy cohort of multiregional samples collected in pancreatic ductal adenocarcinoma (PDAC) patients, into a comprehensive evolutionary analysis. We find that more recently evolved S hort I nterspersed N uclear E lements (SINE), a family of retrotransposable repeats, are more likely to form immunostimulatory double-strand RNAs (dsRNAs). Consequently, younger SINEs are strongly co-regulated with RIG-I like receptor associated type-I interferon genes but anti-correlated with pro-tumorigenic macrophage infiltration. We discover that immunostimulatory SINE expression in tumors is regulated by either L ong I nterspersed N uclear E lements 1 (LINE1/L1) mobility or ADAR1 activity in a TP53 mutation dependent manner. Moreover, L1 retrotransposition activity tracks with tumor evolution and is associated with TP53 mutation status. Altogether, our results suggest pancreatic tumors actively evolve to modulate immunogenic SINE stress and induce pro-tumorigenic inflammation. Our integrative, evolutionary analysis therefore illustrates, for the first time, how dark matter genomic repeats enable tumors to co-evolve with the TME by actively regulating viral mimicry to their selective advantage.
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Liang Z, Chalk AM, Taylor S, Goradia A, Heraud‐Farlow JE, Walkley CR. The phenotype of the most common human ADAR1p150 Zα mutation P193A in mice is partially penetrant. EMBO Rep 2023; 24:e55835. [PMID: 36975179 PMCID: PMC10157378 DOI: 10.15252/embr.202255835] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 02/13/2023] [Accepted: 02/28/2023] [Indexed: 03/29/2023] Open
Abstract
ADAR1 -mediated A-to-I RNA editing is a self-/non-self-discrimination mechanism for cellular double-stranded RNAs. ADAR mutations are one cause of Aicardi-Goutières Syndrome, an inherited paediatric encephalopathy, classed as a "Type I interferonopathy." The most common ADAR1 mutation is a proline 193 alanine (p.P193A) mutation, mapping to the ADAR1p150 isoform-specific Zα domain. Here, we report the development of an independent murine P195A knock-in mouse, homologous to human P193A. The Adar1P195A/P195A mice are largely normal and the mutation is well tolerated. When the P195A mutation is compounded with an Adar1 null allele (Adar1P195A/- ), approximately half the animals are runted with a shortened lifespan while the remaining Adar1P195A/- animals are normal, contrasting with previous reports. The phenotype of the Adar1P195A/- animals is both associated with the parental genotype and partly non-genetic/environmental. Complementation with an editing-deficient ADAR1 (Adar1P195A/E861A ), or the loss of MDA5, rescues phenotypes in the Adar1P195A/- mice.
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Affiliation(s)
- Zhen Liang
- St Vincent's Institute of Medical ResearchFitzroyVic.Australia
- Department of Medicine, Eastern Hill Precinct, Melbourne Medical SchoolUniversity of MelbourneFitzroyVic.Australia
| | - Alistair M Chalk
- St Vincent's Institute of Medical ResearchFitzroyVic.Australia
- Department of Medicine, Eastern Hill Precinct, Melbourne Medical SchoolUniversity of MelbourneFitzroyVic.Australia
| | - Scott Taylor
- St Vincent's Institute of Medical ResearchFitzroyVic.Australia
| | - Ankita Goradia
- St Vincent's Institute of Medical ResearchFitzroyVic.Australia
| | - Jacki E Heraud‐Farlow
- St Vincent's Institute of Medical ResearchFitzroyVic.Australia
- Department of Medicine, Eastern Hill Precinct, Melbourne Medical SchoolUniversity of MelbourneFitzroyVic.Australia
| | - Carl R Walkley
- St Vincent's Institute of Medical ResearchFitzroyVic.Australia
- Department of Medicine, Eastern Hill Precinct, Melbourne Medical SchoolUniversity of MelbourneFitzroyVic.Australia
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Abstract
Our defenses against infection rely on the ability of the immune system to distinguish invading pathogens from self. This task is exceptionally challenging, if not seemingly impossible, in the case of retroviruses that have integrated almost seamlessly into the host. This review examines the limits of innate and adaptive immune responses elicited by endogenous retroviruses and other retroelements, the targets of immune recognition, and the consequences for host health and disease. Contrary to theoretical expectation, endogenous retroelements retain substantial immunogenicity, which manifests most profoundly when their epigenetic repression is compromised, contributing to autoinflammatory and autoimmune disease and age-related inflammation. Nevertheless, recent evidence suggests that regulated immune reactivity to endogenous retroelements is integral to immune system development and function, underpinning cancer immunosurveillance, resistance to infection, and responses to the microbiota. Elucidation of the interaction points with endogenous retroelements will therefore deepen our understanding of immune system function and contribution to disease.
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Affiliation(s)
- George Kassiotis
- Retroviral Immunology Laboratory, The Francis Crick Institute, London, United Kingdom;
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, United Kingdom
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37
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Nakahama T, Kawahara Y. The RNA-editing enzyme ADAR1: a regulatory hub that tunes multiple dsRNA-sensing pathways. Int Immunol 2023; 35:123-133. [PMID: 36469491 DOI: 10.1093/intimm/dxac056] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
Adenosine deaminase acting on RNA 1 (ADAR1) is an RNA-editing enzyme that catalyzes adenosine-to-inosine conversions in double-stranded RNAs (dsRNAs). In mammals, ADAR1 is composed of two isoforms: a nuclear short p110 isoform and a cytoplasmic long p150 isoform. Whereas both isoforms contain right-handed dsRNA-binding and deaminase domains, ADAR1 p150 harbors a Zα domain that binds to left-handed dsRNAs, termed Z-RNAs. Myeloma differentiation-associated gene 5 (MDA5) sensing of endogenous dsRNAs as non-self leads to the induction of type I interferon (IFN)-stimulated genes, but recent studies revealed that ADAR1 p150-mediated RNA editing, but not ADAR1 p110, prevents this MDA5-mediated sensing. ADAR1 p150-specific RNA-editing sites are present and at least a Zα domain-Z-RNA interaction is required for this specificity. Mutations in the ADAR1 gene cause Aicardi-Goutières syndrome (AGS), an infant encephalopathy with type I IFN overproduction. Insertion of a point mutation in the Zα domain of the Adar1 gene induces AGS-like encephalopathy in mice, which is rescued by concurrent deletion of MDA5. This finding indicates that impaired ADAR1 p150-mediated RNA-editing is a mechanism underlying AGS caused by an ADAR1 mutation. ADAR1 p150 also prevents ZBP1 sensing of endogenous Z-RNA, which leads to programmed cell death, via the Zα domain and its RNA-editing activity. Furthermore, ADAR1 prevents protein kinase R (PKR) sensing of endogenous right-handed dsRNAs, which leads to translational shutdown and growth arrest. Thus, ADAR1 acts as a regulatory hub that blocks sensing of endogenous dsRNAs as non-self by multiple sensor proteins, both in RNA editing-dependent and -independent manners, and is a potential therapeutic target for diseases, especially cancer.
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Affiliation(s)
- Taisuke Nakahama
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan.,Integrated Frontier Research for Medical Science Division and RNA Frontier Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Osaka 565-0871, Japan.,Division of Microbiology and Immunology, Center for Infectious Disease Education and Research (CiDER), Osaka University, Suita, Osaka 565-0871, Japan
| | - Yukio Kawahara
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan.,Integrated Frontier Research for Medical Science Division and RNA Frontier Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Osaka 565-0871, Japan.,Division of Microbiology and Immunology, Center for Infectious Disease Education and Research (CiDER), Osaka University, Suita, Osaka 565-0871, Japan
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38
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Nichols PJ, Krall JB, Henen MA, Vögeli B, Vicens Q. Z-RNA biology: a central role in the innate immune response? RNA (NEW YORK, N.Y.) 2023; 29:273-281. [PMID: 36596670 PMCID: PMC9945438 DOI: 10.1261/rna.079429.122] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Z-RNA is a higher-energy, left-handed conformation of RNA, whose function has remained elusive. A growing body of work alludes to regulatory roles for Z-RNA in the immune response. Here, we review how Z-RNA features present in cellular RNAs-especially containing retroelements-could be recognized by a family of winged helix proteins, with an impact on host defense. We also discuss how mutations to specific Z-contacting amino acids disrupt their ability to stabilize Z-RNA, resulting in functional losses. We end by highlighting knowledge gaps in the field, which, if addressed, would significantly advance this active area of research.
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Affiliation(s)
- Parker J Nichols
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Jeffrey B Krall
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Morkos A Henen
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
- Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt
| | - Beat Vögeli
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
- RNA Bioscience Initiative, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Quentin Vicens
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
- RNA Bioscience Initiative, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
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Karki R, Kanneganti TD. ADAR1 and ZBP1 in innate immunity, cell death, and disease. Trends Immunol 2023; 44:201-216. [PMID: 36710220 PMCID: PMC9974732 DOI: 10.1016/j.it.2023.01.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 12/28/2022] [Accepted: 01/04/2023] [Indexed: 01/28/2023]
Abstract
ADAR1 and ZBP1 are the only two mammalian proteins that contain Zα domains, which are thought to bind to nucleic acids in the Z-conformation. These two molecules are crucial in regulating diverse biological processes. While ADAR1-mediated RNA editing supports host survival and development, ZBP1-mediated immune responses provide host defense against infection and disease. Recent studies have expanded our understanding of the functions of ADAR1 and ZBP1 beyond their classical roles and established their fundamental regulation of innate immune responses, including NLRP3 inflammasome activation, inflammation, and cell death. Their roles in these processes have physiological impacts across development, infectious and inflammatory diseases, and cancer. In this review, we discuss the functions of ADAR1 and ZBP1 in regulating innate immune responses in development and disease.
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Affiliation(s)
- Rajendra Karki
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
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40
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Jiang Y, Zhang H, Wang J, Chen J, Guo Z, Liu Y, Hua H. Exploiting RIG-I-like receptor pathway for cancer immunotherapy. J Hematol Oncol 2023; 16:8. [PMID: 36755342 PMCID: PMC9906624 DOI: 10.1186/s13045-023-01405-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/30/2023] [Indexed: 02/10/2023] Open
Abstract
RIG-I-like receptors (RLRs) are intracellular pattern recognition receptors that detect viral or bacterial infection and induce host innate immune responses. The RLRs family comprises retinoic acid-inducible gene 1 (RIG-I), melanoma differentiation-associated gene 5 (MDA5) and laboratory of genetics and physiology 2 (LGP2) that have distinctive features. These receptors not only recognize RNA intermediates from viruses and bacteria, but also interact with endogenous RNA such as the mislocalized mitochondrial RNA, the aberrantly reactivated repetitive or transposable elements in the human genome. Evasion of RLRs-mediated immune response may lead to sustained infection, defective host immunity and carcinogenesis. Therapeutic targeting RLRs may not only provoke anti-infection effects, but also induce anticancer immunity or sensitize "immune-cold" tumors to immune checkpoint blockade. In this review, we summarize the current knowledge of RLRs signaling and discuss the rationale for therapeutic targeting RLRs in cancer. We describe how RLRs can be activated by synthetic RNA, oncolytic viruses, viral mimicry and radio-chemotherapy, and how the RNA agonists of RLRs can be systemically delivered in vivo. The integration of RLRs agonism with RNA interference or CAR-T cells provides new dimensions that complement cancer immunotherapy. Moreover, we update the progress of recent clinical trials for cancer therapy involving RLRs activation and immune modulation. Further studies of the mechanisms underlying RLRs signaling will shed new light on the development of cancer therapeutics. Manipulation of RLRs signaling represents an opportunity for clinically relevant cancer therapy. Addressing the challenges in this field will help develop future generations of cancer immunotherapy.
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Affiliation(s)
- Yangfu Jiang
- Laboratory of Oncogene, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Hongying Zhang
- Laboratory of Oncogene, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Jiao Wang
- School of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
| | - Jinzhu Chen
- Laboratory of Oncogene, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Zeyu Guo
- Laboratory of Oncogene, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Yongliang Liu
- Laboratory of Oncogene, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Hui Hua
- Laboratory of Stem Cell Biology, West China Hospital, Sichuan University, Chengdu, 610041, China.
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41
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RBP-RNA interactions in the control of autoimmunity and autoinflammation. Cell Res 2023; 33:97-115. [PMID: 36599968 PMCID: PMC9892603 DOI: 10.1038/s41422-022-00752-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 11/07/2022] [Indexed: 01/06/2023] Open
Abstract
Autoimmunity and autoinflammation arise from aberrant immunological and inflammatory responses toward self-components, contributing to various autoimmune diseases and autoinflammatory diseases. RNA-binding proteins (RBPs) are essential for immune cell development and function, mainly via exerting post-transcriptional regulation of RNA metabolism and function. Functional dysregulation of RBPs and abnormities in RNA metabolism are closely associated with multiple autoimmune or autoinflammatory disorders. Distinct RBPs play critical roles in aberrant autoreactive inflammatory responses via orchestrating a complex regulatory network consisting of DNAs, RNAs and proteins within immune cells. In-depth characterizations of RBP-RNA interactomes during autoimmunity and autoinflammation will lead to a better understanding of autoimmune pathogenesis and facilitate the development of effective therapeutic strategies. In this review, we summarize and discuss the functions of RBP-RNA interactions in controlling aberrant autoimmune inflammation and their potential as biomarkers and therapeutic targets.
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42
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Adamska JZ, Verma R, Gupta S, Hagan T, Wimmers F, Floyd K, Li Q, Valore EV, Wang Y, Trisal M, Vilches-Moure JG, Subramaniam S, Walkley CR, Suthar MS, Li JB, Pulendran B. Ablation of Adar1 in myeloid cells imprints a global antiviral state in the lung and heightens early immunity against SARS-CoV-2. Cell Rep 2023; 42:112038. [PMID: 36732946 PMCID: PMC9842623 DOI: 10.1016/j.celrep.2023.112038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/25/2022] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Under normal homeostatic conditions, self-double-stranded RNA (self-dsRNA) is modified by adenosine deaminase acting on RNA 1 (ADAR1) to prevent the induction of a type I interferon-mediated inflammatory cascade. Antigen-presenting cells (APCs) sense pathogen-associated molecular patterns, such as dsRNA, to activate the immune response. The impact of ADAR1 on the function of APCs and the consequences to immunity are poorly understood. Here, we show that ADAR1 deletion in CD11c+ APCs leads to (1) a skewed myeloid cell compartment enriched in inflammatory cDC2-like cells, (2) enhanced numbers of activated tissue resident memory T cells in the lung, and (3) the imprinting of a broad antiviral transcriptional signature across both immune and non-immune cells. The resulting changes can be partially reversed by blocking IFNAR1 signaling and promote early resistance against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Our study provides insight into the consequences of self-dsRNA sensing in APCs on the immune system.
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Affiliation(s)
- Julia Z Adamska
- Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford University, Stanford, CA 94304, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Rohit Verma
- Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford University, Stanford, CA 94304, USA
| | - Shakti Gupta
- Department of Bioengineering, University of California, San Diego, San Diego, CA 92093, USA
| | - Thomas Hagan
- Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Florian Wimmers
- Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford University, Stanford, CA 94304, USA
| | - Katharine Floyd
- Department of Pediatrics, Department of Microbiology and Immunology, Emory Vaccine Center, Emory National Primate Center, Emory School of Medicine, Atlanta, GA 30329, USA
| | - Qin Li
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Erika V Valore
- Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford University, Stanford, CA 94304, USA
| | - Yanli Wang
- Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford University, Stanford, CA 94304, USA
| | - Meera Trisal
- Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford University, Stanford, CA 94304, USA
| | - José G Vilches-Moure
- Department of Comparative Medicine, Stanford University, Stanford, CA 94305, USA
| | - Shankar Subramaniam
- Department of Bioengineering, University of California, San Diego, San Diego, CA 92093, USA
| | - Carl R Walkley
- St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia; Department of Medicine, St. Vincent's Hospital, University of Melbourne, Fitzroy, VIC 3065, Australia
| | - Mehul S Suthar
- Department of Pediatrics, Department of Microbiology and Immunology, Emory Vaccine Center, Emory National Primate Center, Emory School of Medicine, Atlanta, GA 30329, USA
| | - Jin Billy Li
- Department of Bioengineering, University of California, San Diego, San Diego, CA 92093, USA
| | - Bali Pulendran
- Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford University, Stanford, CA 94304, USA; Department of Pathology, Stanford University, Stanford, CA 94305, USA; Department of Microbiology & Immunology, Stanford University, Stanford, CA 94305, USA.
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Hu SB, Heraud-Farlow J, Sun T, Liang Z, Goradia A, Taylor S, Walkley CR, Li JB. ADAR1p150 Prevents MDA5 and PKR Activation via Distinct Mechanisms to Avert Fatal Autoinflammation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.25.525475. [PMID: 36747811 PMCID: PMC9900771 DOI: 10.1101/2023.01.25.525475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Effective immunity requires the innate immune system to distinguish foreign (non-self) nucleic acids from cellular (self) nucleic acids. Cellular double-stranded RNAs (dsRNAs) are edited by the RNA editing enzyme ADAR1 to prevent their dsRNA structure pattern being recognized as viral dsRNA by cytoplasmic dsRNA sensors including MDA5, PKR and ZBP1. A loss of ADAR1-mediated RNA editing of cellular dsRNA activates MDA5. However, additional RNA editing-independent functions of ADAR1 have been proposed, but a specific mechanism has not been delineated. We now demonstrate that the loss of ADAR1-mediated RNA editing specifically activates MDA5, while loss of the cytoplasmic ADAR1p150 isoform or its dsRNA binding activity enabled PKR activation. Deleting both MDA5 and PKR resulted in complete rescue of the embryonic lethality of Adar1p150 -/- mice to adulthood, contrasting with the limited or no rescue by removing MDA5, PKR or ZBP1 alone, demonstrating that this is a species conserved function of ADAR1p150. Our findings demonstrate that MDA5 and PKR are the primary in vivo effectors of fatal autoinflammation following the loss of ADAR1p150.
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Z-DNA and Z-RNA: Methods-Past and Future. Methods Mol Biol 2023; 2651:295-329. [PMID: 36892776 DOI: 10.1007/978-1-0716-3084-6_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
A quote attributed to Yogi Berra makes the observation that "It's tough to make predictions, especially about the future," highlighting the difficulties posed to an author writing a manuscript like the present. The history of Z-DNA shows that earlier postulates about its biology have failed the test of time, both those from proponents who were wildly enthusiastic in enunciating roles that till this day still remain elusive to experimental validation and those from skeptics within the larger community who considered the field a folly, presumably because of the limitations in the methods available at that time. If anything, the biological roles we now know for Z-DNA and Z-RNA were not anticipated by anyone, even when those early predictions are interpreted in the most favorable way possible. The breakthroughs in the field were made using a combination of methods, especially those based on human and mouse genetic approaches informed by the biochemical and biophysical characterization of the Zα family of proteins. The first success was with the p150 Zα isoform of ADAR1 (adenosine deaminase RNA specific), with insights into the functions of ZBP1 (Z-DNA-binding protein 1) following soon after from the cell death community. Just as the replacement of mechanical clocks by more accurate designs changed expectations about navigation, the discovery of the roles assigned by nature to alternative conformations like Z-DNA has forever altered our view of how the genome operates. These recent advances have been driven by better methodology and by better analytical approaches. This article will briefly describe the methods that were key to these discoveries and highlight areas where new method development is likely to further advance our knowledge.
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45
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Mocarski ES. Programmed Necrosis in Host Defense. Curr Top Microbiol Immunol 2023; 442:1-40. [PMID: 37563336 DOI: 10.1007/82_2023_264] [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] [Indexed: 08/12/2023]
Abstract
Host control over infectious disease relies on the ability of cells in multicellular organisms to detect and defend against pathogens to prevent disease. Evolution affords mammals with a wide variety of independent immune mechanisms to control or eliminate invading infectious agents. Many pathogens acquire functions to deflect these immune mechanisms and promote infection. Following successful invasion of a host, cell autonomous signaling pathways drive the production of inflammatory cytokines, deployment of restriction factors and induction of cell death. Combined, these innate immune mechanisms attract dendritic cells, neutrophils and macrophages as well as innate lymphoid cells such as natural killer cells that all help control infection. Eventually, the development of adaptive pathogen-specific immunity clears infection and provides immune memory of the encounter. For obligate intracellular pathogens such as viruses, diverse cell death pathways make a pivotal contribution to early control by eliminating host cells before progeny are produced. Pro-apoptotic caspase-8 activity (along with caspase-10 in humans) executes extrinsic apoptosis, a nonlytic form of cell death triggered by TNF family death receptors (DRs). Over the past two decades, alternate extrinsic apoptosis and necroptosis outcomes have been described. Programmed necrosis, or necroptosis, occurs when receptor interacting protein kinase 3 (RIPK3) activates mixed lineage kinase-like (MLKL), causing cell leakage. Thus, activation of DRs, toll-like receptors (TLRs) or pathogen sensor Z-nucleic acid binding protein 1 (ZBP1) initiates apoptosis as well as necroptosis if not blocked by virus-encoded inhibitors. Mammalian cell death pathways are blocked by herpesvirus- and poxvirus-encoded cell death suppressors. Growing evidence has revealed the importance of Z-nucleic acid sensor, ZBP1, in the cell autonomous recognition of both DNA and RNA virus infection. This volume will explore the detente between viruses and cells to manage death machinery and avoid elimination to support dissemination within the host animal.
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Affiliation(s)
- Edward S Mocarski
- Robert W. Woodruff Professor Emeritus, Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, 30322, USA.
- Professor Emeritus, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
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Guo X, Steinman RA, Sheng Y, Cao G, Wiley CA, Wang Q. An AGS-associated mutation in ADAR1 catalytic domain results in early-onset and MDA5-dependent encephalopathy with IFN pathway activation in the brain. J Neuroinflammation 2022; 19:285. [PMID: 36457126 PMCID: PMC9714073 DOI: 10.1186/s12974-022-02646-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 11/15/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Aicardi-Goutières syndrome (AGS) is a severe neurodegenerative disease with clinical features of early-onset encephalopathy and progressive loss of intellectual abilities and motor control. Gene mutations in seven protein-coding genes have been found to be associated with AGS. However, the causative role of these mutations in the early-onset neuropathogenesis has not been demonstrated in animal models, and the mechanism of neurodegeneration of AGS remains ambiguous. METHODS Via CRISPR/Cas-9 technology, we established a mutant mouse model in which a genetic mutation found in AGS patients at the ADAR1 coding gene (Adar) loci was introduced into the mouse genome. A mouse model carrying double gene mutations encoding ADAR1 and MDA-5 was prepared using a breeding strategy. Phenotype, gene expression, RNA sequencing, innate immune pathway activation, and pathologic studies including RNA in situ hybridization (ISH) and immunohistochemistry were used for characterization of the mouse models to determine potential disease mechanisms. RESULTS We established a mouse model bearing a mutation in the catalytic domain of ADAR1, the D1113H mutation found in AGS patients. With this mouse model, we demonstrated a causative role of this mutation for the early-onset brain injuries in AGS and determined the signaling pathway underlying the neuropathogenesis. First, this mutation altered the RNA editing profile in neural transcripts and led to robust IFN-stimulated gene (ISG) expression in the brain. By ISH, the brains of mutant mice showed an unusual, multifocal increased expression of ISGs that was cell-type dependent. Early-onset astrocytosis and microgliosis and later stage calcification in the deep white matter areas were observed in the mutant mice. Brain ISG activation and neuroglial reaction were completely prevented in the Adar D1113H mutant mice by blocking RNA sensing through deletion of the cytosolic RNA receptor MDA-5. CONCLUSIONS The Adar D1113H mutation in the ADAR1 catalytic domain results in early-onset and MDA5-dependent encephalopathy with IFN pathway activation in the mouse brain.
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Affiliation(s)
- Xinfeng Guo
- Department of Surgery, University of Pittsburgh School of Medicine, 200 Lothrop Street, Pittsburgh, PA 15213 USA
| | - Richard A. Steinman
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Yi Sheng
- Magee Women Research Institute, University of Pittsburgh, Pittsburgh, PA USA
| | - Guodong Cao
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Clayton A. Wiley
- Department of Pathology, School of Medicine, University of Pittsburgh, Scaife Hall, 200 Lothrop Street, Pittsburgh, PA 15213 USA
| | - Qingde Wang
- Department of Surgery, University of Pittsburgh School of Medicine, 200 Lothrop Street, Pittsburgh, PA 15213 USA
- V.A. Pittsburgh Health System, Pittsburgh, PA USA
- Pittsburgh Liver Research Center, University of Pittsburgh Medical Center and University of Pittsburgh School of Medicine, Pittsburgh, PA USA
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Naesens L, Muppala S, Acharya D, Nemegeer J, Bogaert D, Lee JH, Staes K, Debacker V, De Bleser P, De Bruyne M, De Baere E, van Gent M, Liu G, Lambrecht BN, Staal J, Kerre T, Beyaert R, Maelfait J, Tavernier SJ, Gack MU, Haerynck F. GTF3A mutations predispose to herpes simplex encephalitis by disrupting biogenesis of the host-derived RIG-I ligand RNA5SP141. Sci Immunol 2022; 7:eabq4531. [PMID: 36399538 PMCID: PMC10075094 DOI: 10.1126/sciimmunol.abq4531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Herpes simplex virus 1 (HSV-1) infects several billion people worldwide and can cause life-threatening herpes simplex encephalitis (HSE) in some patients. Monogenic defects in components of the type I interferon system have been identified in patients with HSE, emphasizing the role of inborn errors of immunity underlying HSE pathogenesis. Here, we identify compound heterozygous loss-of-function mutations in the gene GTF3A encoding for transcription factor IIIA (TFIIIA), a component of the RNA polymerase III complex, in a patient with common variable immunodeficiency and HSE. Patient fibroblasts and GTF3A gene-edited cells displayed impaired HSV-1-induced innate immune responses and enhanced HSV-1 replication. Chromatin immunoprecipitation sequencing analysis identified the 5S ribosomal RNA pseudogene 141 (RNA5SP141), an endogenous ligand of the RNA sensor RIG-I, as a transcriptional target of TFIIIA. GTF3A mutant cells exhibited diminished RNA5SP141 expression and abrogated RIG-I activation upon HSV-1 infection. Our work unveils a crucial role for TFIIIA in transcriptional regulation of a cellular RIG-I agonist and shows that GTF3A genetic defects lead to impaired cell-intrinsic anti-HSV-1 responses and can predispose to HSE.
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Affiliation(s)
- Leslie Naesens
- Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
- Primary Immunodeficiency Research Lab, Center for Primary Immunodeficiency, Jeffrey Modell Diagnosis and Research Center, Ghent University Hospital, Ghent, Belgium
- Florida Research and Innovation Center, Cleveland Clinic, Port St Lucie, FL, USA
| | - Santoshi Muppala
- Florida Research and Innovation Center, Cleveland Clinic, Port St Lucie, FL, USA
| | - Dhiraj Acharya
- Florida Research and Innovation Center, Cleveland Clinic, Port St Lucie, FL, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Josephine Nemegeer
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- Laboratory of Molecular Signaling and Cell death, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Delfien Bogaert
- Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
- Primary Immunodeficiency Research Lab, Center for Primary Immunodeficiency, Jeffrey Modell Diagnosis and Research Center, Ghent University Hospital, Ghent, Belgium
| | - Jung-Hyun Lee
- Florida Research and Innovation Center, Cleveland Clinic, Port St Lucie, FL, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Katrien Staes
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Veronique Debacker
- Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
- Primary Immunodeficiency Research Lab, Center for Primary Immunodeficiency, Jeffrey Modell Diagnosis and Research Center, Ghent University Hospital, Ghent, Belgium
| | - Pieter De Bleser
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- Laboratory of Data Mining and Modeling for Biomedicine, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Marieke De Bruyne
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Elfride De Baere
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Michiel van Gent
- Florida Research and Innovation Center, Cleveland Clinic, Port St Lucie, FL, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - GuanQun Liu
- Florida Research and Innovation Center, Cleveland Clinic, Port St Lucie, FL, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Bart N. Lambrecht
- Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
- Laboratory of Immunoregulation and Mucosal Immunology, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Jens Staal
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- Laboratory of Molecular Signal Transduction in Inflammation, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Tessa Kerre
- Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
- Department of Hematology, Jeffrey Modell Diagnosis and Research Center, Ghent University Hospital, Ghent, Belgium
| | - Rudi Beyaert
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- Laboratory of Molecular Signal Transduction in Inflammation, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Jonathan Maelfait
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- Laboratory of Molecular Signaling and Cell death, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Simon J. Tavernier
- Primary Immunodeficiency Research Lab, Center for Primary Immunodeficiency, Jeffrey Modell Diagnosis and Research Center, Ghent University Hospital, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
- Laboratory of Molecular Signal Transduction in Inflammation, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Michaela U. Gack
- Florida Research and Innovation Center, Cleveland Clinic, Port St Lucie, FL, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Filomeen Haerynck
- Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
- Primary Immunodeficiency Research Lab, Center for Primary Immunodeficiency, Jeffrey Modell Diagnosis and Research Center, Ghent University Hospital, Ghent, Belgium
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Tang Q. Z-nucleic acids: Uncovering the functions from past to present. Eur J Immunol 2022; 52:1700-1711. [PMID: 36165274 PMCID: PMC9827954 DOI: 10.1002/eji.202249968] [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: 04/28/2022] [Revised: 08/15/2022] [Accepted: 09/23/2022] [Indexed: 01/12/2023]
Abstract
Since Z-nucleic acid was identified in the 1970s, much is still unknown about its biological functions and nature in vivo. Recent studies on adenosine deaminase acting on RNA 1 (ADAR1) and Z-DNA-binding protein 1 (ZBP1) have highlighted its function in immune responses. Specifically, Z-RNAs, either endogenous or induced by viral infection, are sensed by ZBP1 and activate necroptosis. Z-RNAs act as the stimuli that induce innate immune responses through various pathways, including melanoma differentiation-associated protein 5 (MAD5)-mitochondrial antiviral-signaling protein (MAVS)-mediated type I IFN activation and proteinase kinase R (PKR)-dependent integrated stress response, and their immunostimulatory potential is curtailed by RNA editing conducted by ADAR1. Aberrant immune responses induced by Z-RNAs are associated with human diseases. They also induce pathogenesis in mice. Unlike Z-RNAs, the biological functions of Z-DNAs were barely studied, especially in mammals. Moreover, the origin or sequence preference of Z-nucleic acids requires further investigation. Such knowledge will expand our understanding of Z-nucleic acids, including from which genomic loci and under which circumstances they form, and the mechanisms by which they participate in the physiological activities. In this review, we provide insights in Z-nucleic acid research and highlight the unsolved puzzles.
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Affiliation(s)
- Qiannan Tang
- Shanghai Institute of ImmunologyDepartment of Immunology and MicrobiologyShanghai Jiao Tong University School of MedicineShanghaiChina,Centre for Immune‐Related Diseases at Shanghai Institute of ImmunologyRuijin Hospital, Shanghai Jiao Tong University School of MedicineShanghaiChina
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49
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Chen W, Li Y, Ruan GX, Huang H, Zhang R, Wang J, Ouyang Y, Li Y, Xu S, Ou X. Adenosine deaminase acting on RNA-1 is essential for early B lymphopoiesis. Cell Rep 2022; 41:111687. [DOI: 10.1016/j.celrep.2022.111687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 09/07/2022] [Accepted: 10/27/2022] [Indexed: 11/23/2022] Open
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50
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Li M, Yan C, Jiao Y, Xu Y, Bai C, Miao R, Jiang J, Liu J. Site-directed RNA editing by harnessing ADARs: advances and challenges. Funct Integr Genomics 2022; 22:1089-1103. [DOI: 10.1007/s10142-022-00910-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 11/04/2022]
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