1
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Liu Q, Huang C, Chen S, Zhu Y, Huang X, Zhao G, Xu Q, Shi Y, Li W, Wang R, Yin X. ADAR1 promotes cisplatin resistance in intrahepatic cholangiocarcinoma by regulating BRCA2 expression through A-to-I editing manner. Cell Prolif 2024; 57:e13659. [PMID: 38773866 PMCID: PMC11471395 DOI: 10.1111/cpr.13659] [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: 03/22/2024] [Revised: 04/20/2024] [Accepted: 05/03/2024] [Indexed: 05/24/2024] Open
Abstract
Aberrant A-to-I RNA editing, mediated by ADAR1 has been found to be associated with increased tumourigenesis and the development of chemotherapy resistance in various types of cancer. Intrahepatic cholangiocarcinoma (iCCA) is a highly aggressive malignancy with a poor prognosis, and overcoming chemotherapy resistance poses a significant clinical challenge. This study aimed to clarify the roles of ADAR1 in tumour resistance to cisplatin in iCCA. We discovered that ADAR1 expression is elevated in iCCA patients, particularly in those resistant to cisplatin, and associated with poor clinical outcomes. Downregulation of ADAR1 can increase the sensitivity of iCCA cells to cisplatin treatment, whereas its overexpression has the inverse effect. By integrating RNA sequencing and Sanger sequencing, we identified BRCA2, a critical DNA damage repair gene, as a downstream target of ADAR1 in iCCA. ADAR1 mediates the A-to-I editing in BRCA2 3'UTR, inhibiting miR-3157-5p binding, consequently increasing BRCA2 mRNA and protein levels. Furthermore, ADAR1 enhances cellular DNA damage repair ability and facilitates cisplatin resistance in iCCA cells. Combining ADAR1 targeting with cisplatin treatment markedly enhances the anticancer efficacy of cisplatin. In conclusion, ADAR1 promotes tumour progression and cisplatin resistance of iCCA. ADAR1 targeting could inform the development of innovative combination therapies for iCCA.
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Affiliation(s)
- Qi Liu
- Department of Pancreato‐Biliary SurgeryThe First Affiliated Hospital of Sun Yat‐sen UniversityGuangzhouChina
| | - Chen‐Song Huang
- Department of Pancreato‐Biliary SurgeryThe First Affiliated Hospital of Sun Yat‐sen UniversityGuangzhouChina
| | - Siyun Chen
- Key Laboratory of Stem Cells and Tissue Engineering (Sun Yat‐sen University)Ministry of EducationGuangzhouChina
| | - Ying‐Qin Zhu
- Department of Pancreato‐Biliary SurgeryThe First Affiliated Hospital of Sun Yat‐sen UniversityGuangzhouChina
| | - Xi‐Tai Huang
- Department of Pancreato‐Biliary SurgeryThe First Affiliated Hospital of Sun Yat‐sen UniversityGuangzhouChina
| | - Guang‐Yin Zhao
- Department of Animal Experiment Center, The First Affiliated HospitalSun Yat‐sen UniversityGuangzhouChina
| | - Qiong‐Cong Xu
- Department of Pancreato‐Biliary SurgeryThe First Affiliated Hospital of Sun Yat‐sen UniversityGuangzhouChina
| | - Yin‐Hao Shi
- Department of Pancreato‐Biliary SurgeryThe First Affiliated Hospital of Sun Yat‐sen UniversityGuangzhouChina
| | - Wen Li
- Laboratory of General Surgery, The First Affiliated HospitalSun Yat‐sen UniversityGuangzhouChina
| | - Ruizhi Wang
- Department of Laboratory Medicine, The First Affiliated HospitalSun Yat‐sen UniversityGuangzhouChina
- Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Xiao‐Yu Yin
- Department of Pancreato‐Biliary SurgeryThe First Affiliated Hospital of Sun Yat‐sen UniversityGuangzhouChina
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2
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Sharma D, Chakraborty S. RNA editing sites and triplet usage in exomes of bat RNA virus genomes of the family Paramyxoviridae. Microb Pathog 2024; 194:106796. [PMID: 39025379 DOI: 10.1016/j.micpath.2024.106796] [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: 02/29/2024] [Revised: 07/09/2024] [Accepted: 07/15/2024] [Indexed: 07/20/2024]
Abstract
Bats contain a diverse spectrum of viral species in their bodies. The RNA virus family Paramyxoviridae tends to infect several vertebrate species, which are accountable for a variety of devastating infections in both humans and animals. Viruses of this kind include measles, mumps, and Hendra. Some synonymous codons are favoured over others in mRNAs during gene-to-protein synthesis process. Such phenomenon is termed as codon usage bias (CUB). Our research emphasized many aspects that shape the CUB of genes in the Paramyxoviridae family found in bats. Here, the nitrogenous base A occurred the most. AT was found to be abundant in the coding sequences of the Paramyxoviridae family. RSCU data revealed that A or T ending codons occurred more frequently than predicted. Furthermore, 3 overrepresented codons (CAT, AGA, and GCA) and 7 underrepresented codons (CCG, TCG, CGC, CGG, CGT, GCG and ACG) were detected in the viral genomes. Correspondence analysis, neutrality plot, and parity plots highlight the combined impact of mutational pressure and natural selection on CUB. The neutrality plot of GC12 against GC3 yielded a regression coefficient value of 0.366, indicating that natural selection had a significant (63.4 %) impact. Moreover, RNA editing analysis was done, which revealed the highest frequency of C to T mutations. The results of our research revealed the pattern of codon usage and RNA editing sites in Paramyxoviridae genomes.
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Affiliation(s)
- Deepika Sharma
- Department of Biotechnology, Assam University, Silchar, 788011, Assam, India.
| | - Supriyo Chakraborty
- Department of Biotechnology, Assam University, Silchar, 788011, Assam, India.
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3
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He Q, Liu C, Liu Q, Wang L, Song L. CgADAR1 involved in regulating the synthesis of interferon-like protein in Crassostrea gigas. FISH & SHELLFISH IMMUNOLOGY 2024; 150:109620. [PMID: 38740229 DOI: 10.1016/j.fsi.2024.109620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 04/24/2024] [Accepted: 05/10/2024] [Indexed: 05/16/2024]
Abstract
Adenosine deaminases acting on RNA 1 (ADAR1) is a dsRNA adenosine (A)-to-inosine (I) editing enzyme that regulates the innate immune response against virus invasion. In the present study, a novel CgADAR1 was identified from the oyster Crassostrea gigas. The open reading frame (ORF) of CgADAR1 was of 3444 bp encoding a peptide of 1147 amino acid residues with two Zα domains, one dsRNA binding motif (DSRM) and one RNA adenosine deaminase domain (ADEAMc). The mRNA transcripts of CgADAR1 were detected in all the examined tissues, with higher expression levels in mantle and gill, which were 7.11-fold and 4.90-fold (p < 0.05) of that in labial palp, respectively. The mRNA transcripts of CgADAR1 in haemocytes were significantly induced at 24 h and 36 h after Poly (A: U) stimulation, which were 6.03-fold (p < 0.01) and 1.37-fold (p < 0.001) of that in control group, respectively. At 48 h after Poly (A:U) stimulation, the mRNA expression of CgRIG-Ⅰ, CgIRF8 and CgIFNLP significantly increased, which were 4.36-fold (p < 0.001), 1.82-fold (p < 0.05) and 1.92-fold (p < 0.05) of that in control group. After CgADAR1 expression was inhibited by RNA interference (RNAi), the mRNA expression levels of CgMDA5, CgRIG-Ⅰ, CgTBK1, CgIRF8 and CgIFNLP were significantly increased, which were 11.88-fold, 11.51-fold, 2.22-fold, 2.85-fold and 2.52-fold of that in control group (p < 0.001), and the phosphorylation level of CgTBK1 was also significantly increased. These results suggested that CgADAR1 played a regulation role in the early stages of viral infection by inhibiting the synthesis of interferon-like protein.
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Affiliation(s)
- Qianqian He
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Dalian Key Laboratory of Aquatic Animal Disease Prevention and Control, Dalian Ocean University, Dalian, 116023, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China
| | - Chang Liu
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Dalian Key Laboratory of Aquatic Animal Disease Prevention and Control, Dalian Ocean University, Dalian, 116023, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China.
| | - Qian Liu
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Dalian Key Laboratory of Aquatic Animal Disease Prevention and Control, Dalian Ocean University, Dalian, 116023, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China
| | - Lingling Wang
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Dalian Key Laboratory of Aquatic Animal Disease Prevention and Control, Dalian Ocean University, Dalian, 116023, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China; Southern Laboratory of Ocean Science and Engineering, Guangdong, Zhuhai, 519000, China
| | - Linsheng Song
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Dalian Key Laboratory of Aquatic Animal Disease Prevention and Control, Dalian Ocean University, Dalian, 116023, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China; Southern Laboratory of Ocean Science and Engineering, Guangdong, Zhuhai, 519000, China.
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4
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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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5
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Song J, Liu Y, Yin Y, Wang H, Zhang X, Li Y, Zhao X, Zhang G, Meng X, Jin Y, Lu D, Yin Y. PTIR1 acts as an isoform of DDX58 and promotes tumor immune resistance through activation of UCHL5. Cell Rep 2023; 42:113388. [PMID: 37934668 DOI: 10.1016/j.celrep.2023.113388] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 09/22/2023] [Accepted: 10/20/2023] [Indexed: 11/09/2023] Open
Abstract
Cancer evades host immune surveillance by virtue of poor immunogenicity. Here, we report an immune suppressor, designated as PTIR1, that acts as a promotor of tumor immune resistance. PTIR1 is selectively induced in human cancers via alternative splicing of DDX58 (RIG-I), and its induction is closely related to poor outcome in patients with cancer. Through blocking the recruitment of leukocytes, PTIR1 facilitates cancer immune escape and tumor-intrinsic resistance to immunotherapeutic treatments. Unlike RIG-I, PTIR1 is capable of binding to the C terminus of UCHL5 and activates its ubiquitinating function, which in turn inhibits immunoproteasome activity and limits neoantigen processing and presentation, consequently blocking T cell recognition and attack against cancer. Moreover, we find that the adenosine deaminase ADAR1 induces A-to-I RNA editing on DDX58 transcript, thus triggering PTIR1 production. Collectively, our data uncover the immunosuppressive role of PTIR1 in tumorigenesis and propose that ADAR1-PTIR1-UCHL5 signaling is a potential cancer immunotherapeutic target.
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Affiliation(s)
- Jia Song
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, Peking University Health Science Center, Beijing 100191, P.R. China
| | - Yang Liu
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, Peking University Health Science Center, Beijing 100191, P.R. China
| | - Yue Yin
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, Peking University Health Science Center, Beijing 100191, P.R. China
| | - Hui Wang
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, Peking University Health Science Center, Beijing 100191, P.R. China
| | - Xin Zhang
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, Peking University Health Science Center, Beijing 100191, P.R. China
| | - Yang Li
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, Peking University Health Science Center, Beijing 100191, P.R. China
| | - Xuyang Zhao
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, Peking University Health Science Center, Beijing 100191, P.R. China
| | - Guangze Zhang
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, Peking University Health Science Center, Beijing 100191, P.R. China
| | - Xiangyan Meng
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, Peking University Health Science Center, Beijing 100191, P.R. China
| | - Yan Jin
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, Peking University Health Science Center, Beijing 100191, P.R. China
| | - Dan Lu
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, Peking University Health Science Center, Beijing 100191, P.R. China.
| | - Yuxin Yin
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, Peking University Health Science Center, Beijing 100191, P.R. China; Institute of Precision Medicine, Peking University Shenzhen Hospital, Shenzhen 518036, P.R. China.
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6
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Cai D, Fraunfelder M, Fujise K, Chen SY. ADAR1 exacerbates ischemic brain injury via astrocyte-mediated neuron apoptosis. Redox Biol 2023; 67:102903. [PMID: 37801857 PMCID: PMC10570147 DOI: 10.1016/j.redox.2023.102903] [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: 09/04/2023] [Revised: 09/19/2023] [Accepted: 09/22/2023] [Indexed: 10/08/2023] Open
Abstract
Astrocytes affect stroke outcomes by acquiring functionally dominant phenotypes. Understanding molecular mechanisms dictating astrocyte functional status after brain ischemia/reperfusion may reveal new therapeutic strategies. Adenosine deaminase acting on RNA (ADAR1), an RNA editing enzyme, is not normally expressed in astrocytes, but highly induced in astrocytes in ischemic stroke lesions. The expression of ADAR1 steeply increased from day 1 to day 7 after middle cerebral artery occlusion (MCAO) for 1 h followed by reperfusion. ADAR1 deficiency markedly ameliorated the volume of the cerebral infarction and neurological deficits as shown by the rotarod and cylinder tests, which was due to the reduction of the numbers of activated astrocytes and microglia. Surprisingly, ADAR1 was mainly expressed in astrocytes while only marginally in microglia. In primary cultured astrocytes, ADAR1 promoted astrocyte proliferation via phosphatidylinositol 3-kinase (PI3K)/Akt pathway. Furthermore, ADAR1 deficiency inhibited brain cell apoptosis in mice with MCAO as well as in activated astrocyte-conditioned medium-induced neurons in vitro. It appeared that ADAR1 induces neuron apoptosis by secretion of IL-1β, IL-6 and TNF-α from astrocytes through the production of reactive oxygen species. These results indicated that ADAR1 is a novel regulator promoting the proliferation of the activated astrocytes following ischemic stroke, which produce various inflammatory cytokines, leading to neuron apoptosis and worsened ischemic stroke outcome.
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Affiliation(s)
- Dunpeng Cai
- Departments of Surgery, University of Missouri School of Medicine, Columbia, MO, USA
| | - Mikayla Fraunfelder
- Departments of Surgery, University of Missouri School of Medicine, Columbia, MO, USA
| | - Ken Fujise
- Harborview Medical Center, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Shi-You Chen
- Departments of Surgery, University of Missouri School of Medicine, Columbia, MO, USA; The Research Service, Harry S. Truman Memorial Veterans Hospital, Columbia, MO, USA.
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7
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Shen S, Zhang LS. The regulation of antiviral innate immunity through non-m 6A RNA modifications. Front Immunol 2023; 14:1286820. [PMID: 37915585 PMCID: PMC10616867 DOI: 10.3389/fimmu.2023.1286820] [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: 08/31/2023] [Accepted: 10/04/2023] [Indexed: 11/03/2023] Open
Abstract
The post-transcriptional RNA modifications impact the dynamic regulation of gene expression in diverse biological and physiological processes. Host RNA modifications play an indispensable role in regulating innate immune responses against virus infection in mammals. Meanwhile, the viral RNAs can be deposited with RNA modifications to interfere with the host immune responses. The N6-methyladenosine (m6A) has boosted the recent emergence of RNA epigenetics, due to its high abundance and a transcriptome-wide widespread distribution in mammalian cells, proven to impact antiviral innate immunity. However, the other types of RNA modifications are also involved in regulating antiviral responses, and the functional roles of these non-m6A RNA modifications have not been comprehensively summarized. In this Review, we conclude the regulatory roles of 2'-O-methylation (Nm), 5-methylcytidine (m5C), adenosine-inosine editing (A-to-I editing), pseudouridine (Ψ), N1-methyladenosine (m1A), N7-methylguanosine (m7G), N6,2'-O-dimethyladenosine (m6Am), and N4-acetylcytidine (ac4C) in antiviral innate immunity. We provide a systematic introduction to the biogenesis and functions of these non-m6A RNA modifications in viral RNA, host RNA, and during virus-host interactions, emphasizing the biological functions of RNA modification regulators in antiviral responses. Furthermore, we discussed the recent research progress in the development of antiviral drugs through non-m6A RNA modifications. Collectively, this Review conveys knowledge and inspiration to researchers in multiple disciplines, highlighting the challenges and future directions in RNA epitranscriptome, immunology, and virology.
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Affiliation(s)
- Shenghai Shen
- Division of Life Science, The Hong Kong University of Science and Technology (HKUST), Kowloon, Hong Kong SAR, China
| | - Li-Sheng Zhang
- Division of Life Science, The Hong Kong University of Science and Technology (HKUST), Kowloon, Hong Kong SAR, China
- Department of Chemistry, The Hong Kong University of Science and Technology (HKUST), Kowloon, Hong Kong SAR, China
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8
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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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9
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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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10
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Uhl S, Jang C, Frere JJ, Jordan TX, Simon AE, tenOever BR. ADAR1 Biology Can Hinder Effective Antiviral RNA Interference. J Virol 2023; 97:e0024523. [PMID: 37017521 PMCID: PMC10134826 DOI: 10.1128/jvi.00245-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 03/10/2023] [Indexed: 04/06/2023] Open
Abstract
Viruses constantly evolve and adapt to the antiviral defenses of their hosts. The biology of viral circumvention of these selective pressures can often be attributed to the acquisition of novel antagonistic gene products or by rapid genome change that prevents host recognition. To study viral evasion of RNA interference (RNAi)-based defenses, we established a robust antiviral system in mammalian cells using recombinant Sendai virus designed to be targeted by endogenous host microRNAs (miRNAs) with perfect complementarity. Using this system, we previously demonstrated the intrinsic ability of positive-strand RNA viruses to escape this selective pressure via homologous recombination, which was not observed in negative-strand RNA viruses. Here, we show that given extensive time, escape of miRNA-targeted Sendai virus was enabled by host adenosine deaminase acting on RNA 1 (ADAR1). Independent of the viral transcript targeted, ADAR1 editing resulted in disruption of the miRNA-silencing motif, suggesting an intolerance for extensive RNA-RNA interactions necessary for antiviral RNAi. This was further supported in Nicotiana benthamiana, where exogenous expression of ADAR1 interfered with endogenous RNAi. Together, these results suggest that ADAR1 diminishes the effectiveness of RNAi and may explain why it is absent in species that utilize this antiviral defense system. IMPORTANCE All life at the cellular level has the capacity to induce an antiviral response. Here, we examine the result of imposing the antiviral response of one branch of life onto another and find evidence for conflict. To determine the consequences of eliciting an RNAi-like defense in mammals, we applied this pressure to a recombinant Sendai virus in cell culture. We find that ADAR1, a host gene involved in regulation of the mammalian response to virus, prevented RNAi-mediated silencing and subsequently allowed for viral replication. In addition, the expression of ADAR1 in Nicotiana benthamiana, which lacks ADARs and has an endogenous RNAi system, suppresses gene silencing. These data indicate that ADAR1 is disruptive to RNAi biology and provide insight into the evolutionary relationship between ADARs and antiviral defenses in eukaryotic life.
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Affiliation(s)
- Skyler Uhl
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Department of Microbiology | Medicine, New York University, New York, New York, USA
| | - Chanyong Jang
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, College Park, Maryland, USA
| | - Justin J. Frere
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Department of Microbiology | Medicine, New York University, New York, New York, USA
| | - Tristan X. Jordan
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Anne E. Simon
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, College Park, Maryland, USA
| | - Benjamin R. tenOever
- Department of Microbiology | Medicine, New York University, New York, New York, USA
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11
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Zhu T, Niu G, Zhang Y, Chen M, Li CY, Hao L, Zhang Z. Host-mediated RNA editing in viruses. Biol Direct 2023; 18:12. [PMID: 36978112 PMCID: PMC10043548 DOI: 10.1186/s13062-023-00366-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Viruses rely on hosts for life and reproduction, cause a variety of symptoms from common cold to AIDS to COVID-19 and provoke public health threats claiming millions of lives around the globe. RNA editing, as a crucial co-/post-transcriptional modification inducing nucleotide alterations on both endogenous and exogenous RNA sequences, exerts significant influences on virus replication, protein synthesis, infectivity and toxicity. Hitherto, a number of host-mediated RNA editing sites have been identified in diverse viruses, yet lacking a full picture of RNA editing-associated mechanisms and effects in different classes of viruses. Here we synthesize the current knowledge of host-mediated RNA editing in a variety of viruses by considering two enzyme families, viz., ADARs and APOBECs, thereby presenting a landscape of diverse editing mechanisms and effects between viruses and hosts. In the ongoing pandemic, our study promises to provide potentially valuable insights for better understanding host-mediated RNA editing on ever-reported and newly-emerging viruses.
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Affiliation(s)
- Tongtong Zhu
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guangyi Niu
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuansheng Zhang
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ming Chen
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chuan-Yun Li
- Laboratory of Bioinformatics and Genomic Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, 100871, China
| | - Lili Hao
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
- China National Center for Bioinformation, Beijing, 100101, China.
| | - Zhang Zhang
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
- China National Center for Bioinformation, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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12
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Herbert A, Balachandran S. Z-DNA enhances immunotherapy by triggering death of inflammatory cancer-associated fibroblasts. J Immunother Cancer 2022; 10:jitc-2022-005704. [PMID: 36450382 PMCID: PMC9716847 DOI: 10.1136/jitc-2022-005704] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2022] [Indexed: 12/05/2022] Open
Abstract
Cancer-associated fibroblasts (CAFs) are a heterogeneous population of cells. At one end of the spectrum are alpha-smooth muscle actin expressing myoCAFs (myofibroblast CAFs) and at the other end are the interferon (IFN) and Janus Kinase/Signal Transducer and Activator of Transcription responsive iCAFs (inflammatory CAFs). Both types of CAFs promote tumor growth. While myoCAFs foster immune exclusion and limit tumor spread, iCAFs create a highly immunosuppressive environment and foster the seeding of distant metastases. However, iCAFs also represent a tumor vulnerability. They are competent to undergo necroptosis, a highly immunogenic form of cell death that is triggered when Z-DNA or Z-RNA (collectively called ZNA) is sensed by the IFN-induced ZNA binding protein 1 (ZBP1). The sequestering of ZNA ligands by the p150 isoform of the double-stranded RNA-specific deaminase ADAR1 protects iCAFs from cell death. ZBP1-dependent necroptosis in iCAFs can be triggered by administering an orally available small molecule that generates sufficient amounts of ZNA to bypass ADAR1 inhibition. The therapeutic approach of targeting Z-prone sequences (called flipons) is agnostic to the mutations driving cancer progression. By exploiting the tumor vulnerability posed by expression of ZBP1-dependent immunogenic cell death pathways in iCAFs, flipon therapeutics offer new hope for improved clinical outcomes.
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Affiliation(s)
- Alan Herbert
- Discovery, InsideOutBio Inc, Charlestown, Massachusetts, USA
| | - Siddharth Balachandran
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA
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13
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Diallo MA, Pirotte S, Hu Y, Morvan L, Rakus K, Suárez NM, PoTsang L, Saneyoshi H, Xu Y, Davison A, Tompa P, Sussman J, Vanderplasschen A. A fish herpesvirus highlights functional diversities among Zα domains related to phase separation induction and A-to-Z conversion. Nucleic Acids Res 2022; 51:806-830. [PMID: 36130731 PMCID: PMC9881149 DOI: 10.1093/nar/gkac761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 08/18/2022] [Accepted: 08/25/2022] [Indexed: 02/06/2023] Open
Abstract
Zalpha (Zα) domains bind to left-handed Z-DNA and Z-RNA. The Zα domain protein family includes cellular (ADAR1, ZBP1 and PKZ) and viral (vaccinia virus E3 and cyprinid herpesvirus 3 (CyHV-3) ORF112) proteins. We studied CyHV-3 ORF112, which contains an intrinsically disordered region and a Zα domain. Genome editing of CyHV-3 indicated that the expression of only the Zα domain of ORF112 was sufficient for normal viral replication in cell culture and virulence in carp. In contrast, its deletion was lethal for the virus. These observations revealed the potential of the CyHV-3 model as a unique platform to compare the exchangeability of Zα domains expressed alone in living cells. Attempts to rescue the ORF112 deletion by a broad spectrum of cellular, viral, and artificial Zα domains showed that only those expressing Z-binding activity, the capacity to induce liquid-liquid phase separation (LLPS), and A-to-Z conversion, could rescue viral replication. For the first time, this study reports the ability of some Zα domains to induce LLPS and supports the biological relevance of dsRNA A-to-Z conversion mediated by Zα domains. This study expands the functional diversity of Zα domains and stimulates new hypotheses concerning the mechanisms of action of proteins containing Zα domains.
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Affiliation(s)
| | | | - Yunlong Hu
- Department of Infectious and Parasitic Diseases, Immunology-Vaccinology, University of Liège, Liège B-4000, Belgium
| | - Léa Morvan
- Department of Infectious and Parasitic Diseases, Immunology-Vaccinology, University of Liège, Liège B-4000, Belgium
| | - Krzysztof Rakus
- Department of Infectious and Parasitic Diseases, Immunology-Vaccinology, University of Liège, Liège B-4000, Belgium,Department of Evolutionary Immunology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow 30387, Poland
| | - Nicolás M Suárez
- MRC-University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
| | - Lee PoTsang
- Department of Infectious and Parasitic Diseases, Immunology-Vaccinology, University of Liège, Liège B-4000, Belgium,Department of Aquaculture, National Taiwan Ocean University, Keelung 202, Taiwan
| | - Hisao Saneyoshi
- Department of Medical Sciences, Division of Chemistry, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Yan Xu
- Department of Medical Sciences, Division of Chemistry, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Andrew J Davison
- MRC-University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
| | - Peter Tompa
- VIB-VUB Center for Structural Biology, Vrije Universiteit Brussel, Brussel B-1050, Belgium
| | - Joel L Sussman
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
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14
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Peng X, Luo Y, Li H, Guo X, Chen H, Ji X, Liang H. RNA editing increases the nucleotide diversity of SARS-CoV-2 in human host cells. PLoS Genet 2022; 18:e1010130. [PMID: 35353808 PMCID: PMC9000099 DOI: 10.1371/journal.pgen.1010130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 04/11/2022] [Accepted: 03/02/2022] [Indexed: 11/18/2022] Open
Abstract
SARS-CoV-2 is a positive-sense, single-stranded RNA virus responsible for the COVID-19 pandemic. It remains unclear whether and to what extent the virus in human host cells undergoes RNA editing, a major RNA modification mechanism. Here we perform a robust bioinformatic analysis of metatranscriptomic data from multiple bronchoalveolar lavage fluid samples of COVID-19 patients, revealing an appreciable number of A-to-I RNA editing candidate sites in SARS-CoV-2. We confirm the enrichment of A-to-I RNA editing signals at these candidate sites through evaluating four characteristics specific to RNA editing: the inferred RNA editing sites exhibit (i) stronger ADAR1 binding affinity predicted by a deep-learning model built from ADAR1 CLIP-seq data, (ii) decreased editing levels in ADAR1-inhibited human lung cells, (iii) local clustering patterns, and (iv) higher RNA secondary structure propensity. Our results have critical implications in understanding the evolution of SARS-CoV-2 as well as in COVID-19 research, such as phylogenetic analysis and vaccine development. The COVID-19 pandemic is caused by SARS-CoV-2, an RNA virus. In the cells of COVID-19 patients, SARS-CoV-2 interacts with human proteins and is potentially subjected to their enzymatic activities. Here we investigated whether human protein enzymes can change the nucleotide sequence of SARS-CoV-2, thereby leaving a unique molecular footprint. We developed a robust computational algorithm to analyze the sequence data of SARS-CoV-2 obtained from lung fluid samples of COVID-19 patients and found that the virus contains new nucleotide changes that are likely induced by ADAR1, a powerful human protein that can modify specific nucleotide positions in many human transcripts. We further confirmed that the characteristics of the nucleotide changes detected in SARS-CoV-2 are similar to those observed in the human genes. Thus, these ADAR1-induced nucleotide changes may represent an under-appreciated force that can affect the evolution of SARS-CoV-2. Our study helps researchers better understand the evolutionary trajectory of SARS-CoV-2.
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Affiliation(s)
- Xinxin Peng
- Precision Scientific (Beijing) Co., Ltd., Beijing, China
| | - Yikai Luo
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
- Graduate Program in Quantitative and Computational Biosciences, Baylor College of Medicine, Houston, Texas, United States of America
| | - Hongyue Li
- Precision Scientific (Beijing) Co., Ltd., Beijing, China
| | - Xuejiao Guo
- Precision Scientific (Beijing) Co., Ltd., Beijing, China
| | - Hu Chen
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Xuwo Ji
- Precision Scientific (Beijing) Co., Ltd., Beijing, China
| | - Han Liang
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
- Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
- * E-mail:
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15
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Yu Z, Luo R, Li Y, Li X, Yang Z, Peng J, Huang K. ADAR1 inhibits adipogenesis and obesity by interacting with dicer to promote the maturation of miR-155-5P. J Cell Sci 2022; 135:274090. [PMID: 35067718 DOI: 10.1242/jcs.259333] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 01/08/2022] [Indexed: 11/20/2022] Open
Abstract
Adipogenesis is closely related to various metabolic diseases, such as obesity, type 2 diabetes, cardiovascular diseases, and cancer. This cellular process is highly dependent on the expression and sequential activation of a diverse group of transcription factors. Here, we report that ADAR1 could inhibit adipogenesis through binding with Dicer, resulting in enhanced production of miR-155-5p, which downregulates the adipogenic early transcription factor C/EBPβ. Consequently, the expression levels of late transcription factors (C/ebpα and PPARγ) are reduced and adipogenesis is inhibited. More importantly, in vivo studies reveal that overexpression of ADAR1 suppresses white adipose tissue expansion in high fat diet-induced obese mice, leading to improved metabolic phenotypes such as insulin sensitivity and glucose tolerance.
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Affiliation(s)
- Zuying Yu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ruijie Luo
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yutian Li
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, USA
| | - Xiaoguang Li
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhengrui Yang
- Department of Cardiology, The 2nd people's Hospital of Lincang city, Lincang, China
| | - Jiangtong Peng
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Cardiology, The 2nd people's Hospital of Lincang city, Lincang, China
| | - Kai Huang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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16
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Guillemin A, Kumar A, Wencker M, Ricci EP. Shaping the Innate Immune Response Through Post-Transcriptional Regulation of Gene Expression Mediated by RNA-Binding Proteins. Front Immunol 2022; 12:796012. [PMID: 35087521 PMCID: PMC8787094 DOI: 10.3389/fimmu.2021.796012] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/13/2021] [Indexed: 12/20/2022] Open
Abstract
Innate immunity is the frontline of defense against infections and tissue damage. It is a fast and semi-specific response involving a myriad of processes essential for protecting the organism. These reactions promote the clearance of danger by activating, among others, an inflammatory response, the complement cascade and by recruiting the adaptive immunity. Any disequilibrium in this functional balance can lead to either inflammation-mediated tissue damage or defense inefficiency. A dynamic and coordinated gene expression program lies at the heart of the innate immune response. This expression program varies depending on the cell-type and the specific danger signal encountered by the cell and involves multiple layers of regulation. While these are achieved mainly via transcriptional control of gene expression, numerous post-transcriptional regulatory pathways involving RNA-binding proteins (RBPs) and other effectors play a critical role in its fine-tuning. Alternative splicing, translational control and mRNA stability have been shown to be tightly regulated during the innate immune response and participate in modulating gene expression in a global or gene specific manner. More recently, microRNAs assisting RBPs and post-transcriptional modification of RNA bases are also emerging as essential players of the innate immune process. In this review, we highlight the numerous roles played by specific RNA-binding effectors in mediating post-transcriptional control of gene expression to shape innate immunity.
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Affiliation(s)
- Anissa Guillemin
- LBMC, Laboratoire de Biologie et Modelisation de la Cellule, Université de Lyon, ENS de Lyon, Universite Claude Bernard Lyon 1, CNRS, UMR 5239, INSERM, U1293, Lyon, France
| | - Anuj Kumar
- CRCL, Centre de Recherche en Cancérologie de Lyon, INSERM U1052, CNRS UMR 5286, Lyon, France
| | - Mélanie Wencker
- LBMC, Laboratoire de Biologie et Modelisation de la Cellule, Université de Lyon, ENS de Lyon, Universite Claude Bernard Lyon 1, CNRS, UMR 5239, INSERM, U1293, Lyon, France
- CIRI, Centre International de Recherche en Infectiologie, Université de Lyon, ENS de Lyon, CNRS, UMR 5308, INSERM, Lyon, France
| | - Emiliano P. Ricci
- LBMC, Laboratoire de Biologie et Modelisation de la Cellule, Université de Lyon, ENS de Lyon, Universite Claude Bernard Lyon 1, CNRS, UMR 5239, INSERM, U1293, Lyon, France
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17
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Liao Y, Guo S, Liu G, Qiu Z, Wang J, Yang D, Tian X, Qiao Z, Ma Z, Liu Z. Host Non-Coding RNA Regulates Influenza A Virus Replication. Viruses 2021; 14:v14010051. [PMID: 35062254 PMCID: PMC8779696 DOI: 10.3390/v14010051] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 12/21/2021] [Accepted: 12/21/2021] [Indexed: 12/12/2022] Open
Abstract
Outbreaks of influenza, caused by the influenza A virus (IAV), occur almost every year in various regions worldwide, seriously endangering human health. Studies have shown that host non-coding RNA is an important regulator of host-virus interactions in the process of IAV infection. In this paper, we comprehensively analyzed the research progress on host non-coding RNAs with regard to the regulation of IAV replication. According to the regulation mode of host non-coding RNAs, the signal pathways involved, and the specific target genes, we found that a large number of host non-coding RNAs directly targeted the PB1 and PB2 proteins of IAV. Nonstructural protein 1 and other key genes regulate the replication of IAV and indirectly participate in the regulation of the retinoic acid-induced gene I-like receptor signaling pathway, toll-like receptor signaling pathway, Janus kinase signal transducer and activator of transcription signaling pathway, and other major intracellular viral response signaling pathways to regulate the replication of IAV. Based on the above findings, we mapped the regulatory network of host non-coding RNAs in the innate immune response to the influenza virus. These findings will provide a more comprehensive understanding of the function and mechanism of host non-coding RNAs in the cellular anti-virus response as well as clues to the mechanism of cell-virus interactions and the discovery of antiviral drug targets.
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Affiliation(s)
- Yuejiao Liao
- Gansu Tech Innovation Center of Animal Cell, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China; (Y.L.); (S.G.); (G.L.); (Z.Q.); (J.W.); (D.Y.); (Z.Q.); (Z.M.)
- Life Science and Engineering College, Northwest Minzu University, Lanzhou 730030, China;
| | - Shouqing Guo
- Gansu Tech Innovation Center of Animal Cell, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China; (Y.L.); (S.G.); (G.L.); (Z.Q.); (J.W.); (D.Y.); (Z.Q.); (Z.M.)
- Life Science and Engineering College, Northwest Minzu University, Lanzhou 730030, China;
| | - Geng Liu
- Gansu Tech Innovation Center of Animal Cell, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China; (Y.L.); (S.G.); (G.L.); (Z.Q.); (J.W.); (D.Y.); (Z.Q.); (Z.M.)
- Life Science and Engineering College, Northwest Minzu University, Lanzhou 730030, China;
| | - Zhenyu Qiu
- Gansu Tech Innovation Center of Animal Cell, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China; (Y.L.); (S.G.); (G.L.); (Z.Q.); (J.W.); (D.Y.); (Z.Q.); (Z.M.)
- Life Science and Engineering College, Northwest Minzu University, Lanzhou 730030, China;
| | - Jiamin Wang
- Gansu Tech Innovation Center of Animal Cell, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China; (Y.L.); (S.G.); (G.L.); (Z.Q.); (J.W.); (D.Y.); (Z.Q.); (Z.M.)
- Key Laboratory of Biotechnology & Bioengineering of State Ethnic Affairs Commission, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China
| | - Di Yang
- Gansu Tech Innovation Center of Animal Cell, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China; (Y.L.); (S.G.); (G.L.); (Z.Q.); (J.W.); (D.Y.); (Z.Q.); (Z.M.)
- Key Laboratory of Biotechnology & Bioengineering of State Ethnic Affairs Commission, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China
| | - Xiaojing Tian
- Life Science and Engineering College, Northwest Minzu University, Lanzhou 730030, China;
- Key Laboratory of Biotechnology & Bioengineering of State Ethnic Affairs Commission, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China
| | - Ziling Qiao
- Gansu Tech Innovation Center of Animal Cell, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China; (Y.L.); (S.G.); (G.L.); (Z.Q.); (J.W.); (D.Y.); (Z.Q.); (Z.M.)
- Key Laboratory of Biotechnology & Bioengineering of State Ethnic Affairs Commission, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China
| | - Zhongren Ma
- Gansu Tech Innovation Center of Animal Cell, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China; (Y.L.); (S.G.); (G.L.); (Z.Q.); (J.W.); (D.Y.); (Z.Q.); (Z.M.)
- Key Laboratory of Biotechnology & Bioengineering of State Ethnic Affairs Commission, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China
| | - Zhenbin Liu
- Gansu Tech Innovation Center of Animal Cell, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China; (Y.L.); (S.G.); (G.L.); (Z.Q.); (J.W.); (D.Y.); (Z.Q.); (Z.M.)
- Key Laboratory of Biotechnology & Bioengineering of State Ethnic Affairs Commission, Biomedical Research Center, Northwest Minzu University, Lanzhou 730030, China
- Correspondence:
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18
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Piontkivska H, Wales-McGrath B, Miyamoto M, Wayne ML. ADAR Editing in Viruses: An Evolutionary Force to Reckon with. Genome Biol Evol 2021; 13:evab240. [PMID: 34694399 PMCID: PMC8586724 DOI: 10.1093/gbe/evab240] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2021] [Indexed: 02/06/2023] Open
Abstract
Adenosine Deaminases that Act on RNA (ADARs) are RNA editing enzymes that play a dynamic and nuanced role in regulating transcriptome and proteome diversity. This editing can be highly selective, affecting a specific site within a transcript, or nonselective, resulting in hyperediting. ADAR editing is important for regulating neural functions and autoimmunity, and has a key role in the innate immune response to viral infections, where editing can have a range of pro- or antiviral effects and can contribute to viral evolution. Here we examine the role of ADAR editing across a broad range of viral groups. We propose that the effect of ADAR editing on viral replication, whether pro- or antiviral, is better viewed as an axis rather than a binary, and that the specific position of a given virus on this axis is highly dependent on virus- and host-specific factors, and can change over the course of infection. However, more research needs to be devoted to understanding these dynamic factors and how they affect virus-ADAR interactions and viral evolution. Another area that warrants significant attention is the effect of virus-ADAR interactions on host-ADAR interactions, particularly in light of the crucial role of ADAR in regulating neural functions. Answering these questions will be essential to developing our understanding of the relationship between ADAR editing and viral infection. In turn, this will further our understanding of the effects of viruses such as SARS-CoV-2, as well as many others, and thereby influence our approach to treating these deadly diseases.
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Affiliation(s)
- Helen Piontkivska
- Department of Biological Sciences, Kent State University, Ohio, USA
- School of Biomedical Sciences, Kent State University, Ohio, USA
- Brain Health Research Institute, Kent State University, Ohio, USA
| | | | - Michael Miyamoto
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Marta L Wayne
- Department of Biology, University of Florida, Gainesville, Florida, USA
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19
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Tang Q, Rigby RE, Young GR, Hvidt AK, Davis T, Tan TK, Bridgeman A, Townsend AR, Kassiotis G, Rehwinkel J. Adenosine-to-inosine editing of endogenous Z-form RNA by the deaminase ADAR1 prevents spontaneous MAVS-dependent type I interferon responses. Immunity 2021; 54:1961-1975.e5. [PMID: 34525337 PMCID: PMC8459395 DOI: 10.1016/j.immuni.2021.08.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 05/13/2021] [Accepted: 08/11/2021] [Indexed: 01/05/2023]
Abstract
Nucleic acids are powerful triggers of innate immunity and can adopt the Z-conformation, an unusual left-handed double helix. Here, we studied the biological function(s) of Z-RNA recognition by the adenosine deaminase ADAR1, mutations in which cause Aicardi-Goutières syndrome. Adar1mZα/mZα mice, bearing two point mutations in the Z-nucleic acid binding (Zα) domain that abolish Z-RNA binding, displayed spontaneous induction of type I interferons (IFNs) in multiple organs, including in the lung, where both stromal and hematopoietic cells showed IFN-stimulated gene (ISG) induction. Lung neutrophils expressed ISGs induced by the transcription factor IRF3, indicating an initiating role for neutrophils in this IFN response. The IFN response in Adar1mZα/mZα mice required the adaptor MAVS, implicating cytosolic RNA sensing. Adenosine-to-inosine changes were enriched in transposable elements and revealed a specific requirement of ADAR1's Zα domain in editing of a subset of RNAs. Thus, endogenous RNAs in Z-conformation have immunostimulatory potential curtailed by ADAR1, with relevance to autoinflammatory disease in humans.
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Affiliation(s)
- Qiannan Tang
- Medical Research Council Human Immunology Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Rachel E Rigby
- Medical Research Council Human Immunology Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - George R Young
- Bioinformatics and Biostatistics STP, The Francis Crick Institute, London, NW1 1AT, UK
| | - Astrid Korning Hvidt
- Medical Research Council Human Immunology Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Tanja Davis
- Medical Research Council Human Immunology Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Tiong Kit Tan
- Medical Research Council Human Immunology Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Anne Bridgeman
- Medical Research Council Human Immunology Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Alain R Townsend
- Medical Research Council Human Immunology Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DS, UK; Centre for Translational Immunology, Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, OX3 7FZ, UK
| | - George Kassiotis
- Retroviral Immunology, The Francis Crick Institute, London, NW 1AT, UK; Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, W2 1NY, UK
| | - Jan Rehwinkel
- Medical Research Council Human Immunology Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DS, UK.
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Corbet GA, Burke JM, Parker R. ADAR1 limits stress granule formation through both translation-dependent and translation-independent mechanisms. J Cell Sci 2021; 134:272063. [PMID: 34397095 DOI: 10.1242/jcs.258783] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 08/05/2021] [Indexed: 11/20/2022] Open
Abstract
Stress granules (SGs) are cytoplasmic assemblies of RNA and protein that form when translation is repressed during the integrated stress response. SGs assemble from the combination of RNA-RNA, RNA-protein and protein-protein interactions between messenger ribonucleoprotein complexes (mRNPs). The protein adenosine deaminase acting on RNA 1 (ADAR1, also known as ADAR) recognizes and modifies double-stranded RNAs (dsRNAs) within cells to prevent an aberrant innate immune response. ADAR1 localizes to SGs, and since RNA-RNA interactions contribute to SG assembly and dsRNA induces SGs, we examined how ADAR1 affects SG formation. First, we demonstrate that ADAR1 depletion triggers SGs by allowing endogenous dsRNA to activate the integrated stress response through activation of PKR (also known as EIF2AK2) and translation repression. However, we also show that ADAR1 limits SG formation independently of translation inhibition. ADAR1 repression of SGs is independent of deaminase activity but is dependent on dsRNA-binding activity, suggesting a model where ADAR1 binding limits RNA-RNA and/or RNA-protein interactions necessary for recruitment to SGs. Given that ADAR1 expression is induced during viral infection, these findings have implications for the role of ADAR1 in the antiviral response. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Giulia A Corbet
- Department of Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - James M Burke
- Department of Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - Roy Parker
- Department of Biochemistry, University of Colorado, Boulder, CO 80303, USA.,Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA
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21
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de Reuver R, Dierick E, Wiernicki B, Staes K, Seys L, De Meester E, Muyldermans T, Botzki A, Lambrecht BN, Van Nieuwerburgh F, Vandenabeele P, Maelfait J. ADAR1 interaction with Z-RNA promotes editing of endogenous double-stranded RNA and prevents MDA5-dependent immune activation. Cell Rep 2021; 36:109500. [PMID: 34380029 DOI: 10.1016/j.celrep.2021.109500] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 05/14/2021] [Accepted: 07/15/2021] [Indexed: 02/06/2023] Open
Abstract
Loss of function of adenosine deaminase acting on double-stranded RNA (dsRNA)-1 (ADAR1) causes the severe autoinflammatory disease Aicardi-Goutières syndrome (AGS). ADAR1 converts adenosines into inosines within dsRNA. This process called A-to-I editing masks self-dsRNA from detection by the antiviral dsRNA sensor MDA5. ADAR1 binds to dsRNA in both the canonical A-form and the poorly defined Z conformation (Z-RNA). Mutations in the Z-RNA-binding Zα domain of ADAR1 are common in patients with AGS. How loss of ADAR1/Z-RNA interaction contributes to disease development is unknown. We demonstrate that abrogated binding of ADAR1 to Z-RNA leads to reduced A-to-I editing of dsRNA structures formed by base pairing of inversely oriented short interspersed nuclear elements. Preventing ADAR1 binding to Z-RNA triggers an MDA5/MAVS-mediated type I interferon response and leads to the development of lethal autoinflammation in mice. This shows that the interaction between ADAR1 and Z-RNA restricts sensing of self-dsRNA and prevents AGS development.
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Affiliation(s)
- Richard de Reuver
- VIB-UGent Center for Inflammation Research, 9052 Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium
| | - Evelien Dierick
- VIB-UGent Center for Inflammation Research, 9052 Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium
| | - Bartosz Wiernicki
- VIB-UGent Center for Inflammation Research, 9052 Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium
| | - Katrien Staes
- VIB-UGent Center for Inflammation Research, 9052 Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium
| | - Leen Seys
- VIB-UGent Center for Inflammation Research, 9052 Ghent, Belgium; Department of Internal Medicine and Pediatrics, Ghent University, 9000 Ghent, Belgium
| | - Ellen De Meester
- Department of Internal Medicine and Pediatrics, Ghent University, 9000 Ghent, Belgium
| | | | | | - Bart N Lambrecht
- VIB-UGent Center for Inflammation Research, 9052 Ghent, Belgium; Department of Internal Medicine and Pediatrics, Ghent University, 9000 Ghent, Belgium; Department of Pulmonary Medicine, Erasmus University Medical Center Rotterdam, 3015 GJ Rotterdam, the Netherlands
| | - Filip Van Nieuwerburgh
- NXTGNT, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Laboratory of Pharmaceutical Biotechnology, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Peter Vandenabeele
- VIB-UGent Center for Inflammation Research, 9052 Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium
| | - Jonathan Maelfait
- VIB-UGent Center for Inflammation Research, 9052 Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium.
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22
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Kim JI, Nakahama T, Yamasaki R, Costa Cruz PH, Vongpipatana T, Inoue M, Kanou N, Xing Y, Todo H, Shibuya T, Kato Y, Kawahara Y. RNA editing at a limited number of sites is sufficient to prevent MDA5 activation in the mouse brain. PLoS Genet 2021; 17:e1009516. [PMID: 33983932 PMCID: PMC8118328 DOI: 10.1371/journal.pgen.1009516] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/28/2021] [Indexed: 12/22/2022] Open
Abstract
Adenosine deaminase acting on RNA 1 (ADAR1), an enzyme responsible for adenosine-to-inosine RNA editing, is composed of two isoforms: nuclear p110 and cytoplasmic p150. Deletion of Adar1 or Adar1 p150 genes in mice results in embryonic lethality with overexpression of interferon-stimulating genes (ISGs), caused by the aberrant recognition of unedited endogenous transcripts by melanoma differentiation-associated protein 5 (MDA5). However, among numerous RNA editing sites, how many RNA sites require editing, especially by ADAR1 p150, to avoid MDA5 activation and whether ADAR1 p110 contributes to this function remains elusive. In particular, ADAR1 p110 is abundant in the mouse brain where a subtle amount of ADAR1 p150 is expressed, whereas ADAR1 mutations cause Aicardi-Goutières syndrome, in which the brain is one of the most affected organs accompanied by the elevated expression of ISGs. Therefore, understanding RNA editing-mediated prevention of MDA5 activation in the brain is especially important. Here, we established Adar1 p110-specific knockout mice, in which the upregulated expression of ISGs was not observed. This result suggests that ADAR1 p150-mediated RNA editing is enough to suppress MDA5 activation. Therefore, we further created Adar1 p110/Adar2 double knockout mice to identify ADAR1 p150-mediated editing sites. This analysis demonstrated that although the elevated expression of ISGs was not observed, only less than 2% of editing sites were preserved in the brains of Adar1 p110/Adar2 double knockout mice. Of note, we found that some sites were highly edited, which was comparable to those found in wild-type mice, indicating the presence of ADAR1 p150-specific sites. These data suggest that RNA editing at a very limited sites, which is mediated by a subtle amount of ADAR1 p150, is sufficient to prevents MDA5 activation, at least in the mouse brain.
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Affiliation(s)
- Jung In Kim
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Taisuke Nakahama
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Ryuichiro Yamasaki
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Pedro Henrique Costa Cruz
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Tuangtong Vongpipatana
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Maal Inoue
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Nao Kanou
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yanfang Xing
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Hiroyuki Todo
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Toshiharu Shibuya
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yuki Kato
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
- Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Japan
| | - Yukio Kawahara
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
- Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Japan
- Genome Editing Research and Development Center, Graduate School of Medicine, Osaka University, Suita, Japan
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23
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Abstract
C6 deamination of adenosine (A) to inosine (I) in double-stranded RNA (dsRNA) is catalyzed by a family of enzymes known as ADARs (adenosine deaminases acting on RNA) encoded by three genes in mammals. Alternative promoters and splicing produce two ADAR1 proteins, an interferon-inducible cytoplasmic p150 and a constitutively expressed p110 that like ADAR2 is a nuclear enzyme. ADAR3 lacks deaminase activity. A-to-I editing occurs with both viral and cellular RNAs. Deamination activity is dependent on dsRNA substrate structure and regulatory RNA-binding proteins and ranges from highly site selective with hepatitis D RNA and glutamate receptor precursor messenger RNA (pre-mRNA) to hyperediting of measles virus and polyomavirus transcripts and cellular inverted Alu elements. Because I base-pairs as guanosine instead of A, editing can alter mRNA decoding, pre-mRNA splicing, and microRNA silencing. Editing also alters dsRNA structure, thereby suppressing innate immune responses including interferon production and action. Expected final online publication date for the Annual Review of Virology, Volume 8 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Christian K Pfaller
- Division of Veterinary Medicine, Paul-Ehrlich-Institute, Langen 63225, Germany
| | - Cyril X George
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California 93106, USA;
| | - Charles E Samuel
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California 93106, USA;
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24
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Transcriptional and Non-Transcriptional Activation, Posttranslational Modifications, and Antiviral Functions of Interferon Regulatory Factor 3 and Viral Antagonism by the SARS-Coronavirus. Viruses 2021; 13:v13040575. [PMID: 33805458 PMCID: PMC8066409 DOI: 10.3390/v13040575] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 12/12/2022] Open
Abstract
The immune system defends against invading pathogens through the rapid activation of innate immune signaling pathways. Interferon regulatory factor 3 (IRF3) is a key transcription factor activated in response to virus infection and is largely responsible for establishing an antiviral state in the infected host. Studies in Irf3−/− mice have demonstrated the absence of IRF3 imparts a high degree of susceptibility to a wide range of viral infections. Virus infection causes the activation of IRF3 to transcribe type-I interferon (e.g., IFNβ), which is responsible for inducing the interferon-stimulated genes (ISGs), which act at specific stages to limit virus replication. In addition to its transcriptional function, IRF3 is also activated to trigger apoptosis of virus-infected cells, as a mechanism to restrict virus spread within the host, in a pathway called RIG-I-like receptor-induced IRF3 mediated pathway of apoptosis (RIPA). These dual functions of IRF3 work in concert to mediate protective immunity against virus infection. These two pathways are activated differentially by the posttranslational modifications (PTMs) of IRF3. Moreover, PTMs regulate not only IRF3 activation and function, but also protein stability. Consequently, many viruses utilize viral proteins or hijack cellular enzymes to inhibit IRF3 functions. This review will describe the PTMs that regulate IRF3′s RIPA and transcriptional activities and use coronavirus as a model virus capable of antagonizing IRF3-mediated innate immune responses. A thorough understanding of the cellular control of IRF3 and the mechanisms that viruses use to subvert this system is critical for developing novel therapies for virus-induced pathologies.
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