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Xi J, Snieckute G, Martínez JF, Arendrup FSW, Asthana A, Gaughan C, Lund AH, Bekker-Jensen S, Silverman RH. Initiation of a ZAKα-dependent ribotoxic stress response by the innate immunity endoribonuclease RNase L. Cell Rep 2024; 43:113998. [PMID: 38551960 PMCID: PMC11090160 DOI: 10.1016/j.celrep.2024.113998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 02/13/2024] [Accepted: 03/08/2024] [Indexed: 04/09/2024] Open
Abstract
RNase L is an endoribonuclease of higher vertebrates that functions in antiviral innate immunity. Interferons induce oligoadenylate synthetase enzymes that sense double-stranded RNA of viral origin leading to the synthesis of 2',5'-oligoadenylate (2-5A) activators of RNase L. However, it is unknown precisely how RNase L remodels the host cell transcriptome. To isolate effects of RNase L from other effects of double-stranded RNA or virus, 2-5A is directly introduced into cells. Here, we report that RNase L activation by 2-5A causes a ribotoxic stress response involving the MAP kinase kinase kinase (MAP3K) ZAKα, MAP2Ks, and the stress-activated protein kinases JNK and p38α. RNase L activation profoundly alters the transcriptome by widespread depletion of mRNAs associated with different cellular functions but also by JNK/p38α-stimulated induction of inflammatory genes. These results show that the 2-5A/RNase L system triggers a protein kinase cascade leading to proinflammatory signaling and apoptosis.
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Affiliation(s)
- Jiajia Xi
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH 44195, USA.
| | - Goda Snieckute
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark; Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - José Francisco Martínez
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark; Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | | | - Abhishek Asthana
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH 44195, USA
| | - Christina Gaughan
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH 44195, USA
| | - Anders H Lund
- Biotech Research and Innovation Center, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
| | - Simon Bekker-Jensen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark; Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark.
| | - Robert H Silverman
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH 44195, USA.
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2
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Watkins JM, Burke JM. RNase L-induced bodies sequester subgenomic flavivirus RNAs and re-establish host RNA decay. bioRxiv 2024:2024.03.25.586660. [PMID: 38585896 PMCID: PMC10996650 DOI: 10.1101/2024.03.25.586660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Subgenomic flavivirus RNAs (sfRNAs) are structured RNA elements encoded in the 3'-UTR of flaviviruses that promote viral infection by inhibiting cellular RNA decay machinery. Herein, we analyze the production of sfRNAs using single-molecule RNA fluorescence in situ hybridization (smRNA-FISH) and super-resolution microscopy during West Nile virus, Zika virus, or Dengue virus serotype 2 infection. We show that sfRNAs are initially localized diffusely in the cytosol or in processing bodies (P-bodies). However, upon activation of the host antiviral endoribonuclease, Ribonuclease L (RNase L), nearly all sfRNAs re-localize to antiviral biological condensates known as RNase L-induced bodies (RLBs). RLB-mediated sequestration of sfRNAs reduces sfRNA association with RNA decay machinery in P-bodies, which coincides with increased viral RNA decay. These findings establish a role of RLBs in promoting viral RNA decay, demonstrating the complex host-pathogen interactions at the level of RNA decay and biological condensation.
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Affiliation(s)
- J. Monty Watkins
- Department of Molecular Medicine, The Herbert Wertheim University of Florida Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL, United States of America
- Department of Immunology and Microbiology, The Herbert Wertheim University of Florida Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL, United States of America
- Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, FL, USA
| | - James M. Burke
- Department of Molecular Medicine, The Herbert Wertheim University of Florida Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL, United States of America
- Department of Immunology and Microbiology, The Herbert Wertheim University of Florida Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL, United States of America
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Witwit H, Khafaji R, Salaniwal A, Kim AS, Cubitt B, Jackson N, Ye C, Weiss SR, Martinez-Sobrido L, de la Torre JC. Activation of protein kinase receptor (PKR) plays a pro-viral role in mammarenavirus-infected cells. J Virol 2024; 98:e0188323. [PMID: 38376197 PMCID: PMC10949842 DOI: 10.1128/jvi.01883-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 01/26/2024] [Indexed: 02/21/2024] Open
Abstract
Many viruses, including mammarenaviruses, have evolved mechanisms to counteract different components of the host cell innate immunity, which is required to facilitate robust virus multiplication. The double-stranded RNA (dsRNA) sensor protein kinase receptor (PKR) pathway plays a critical role in the cell anti-viral response. Whether PKR can restrict the multiplication of the Old World mammarenavirus lymphocytic choriomeningitis virus (LCMV) and the mechanisms by which LCMV may counteract the anti-viral functions of PKR have not yet been investigated. Here we present evidence that LCMV infection results in very limited levels of PKR activation, but LCMV multiplication is enhanced in the absence of PKR. In contrast, infection with a recombinant LCMV with a mutation affecting the 3'-5' exonuclease (ExoN) activity of the viral nucleoprotein resulted in robust PKR activation in the absence of detectable levels of dsRNA, which was associated with severely restricted virus multiplication that was alleviated in the absence of PKR. However, pharmacological inhibition of PKR activation resulted in reduced levels of LCMV multiplication. These findings uncovered a complex role of the PKR pathway in LCMV-infected cells involving both pro- and anti-viral activities.IMPORTANCEAs with many other viruses, the prototypic Old World mammarenavirus LCMV can interfere with the host cell innate immune response to infection, which includes the dsRNA sensor PKR pathway. A detailed understanding of LCMV-PKR interactions can provide novel insights about mammarenavirus-host cell interactions and facilitate the development of effective anti-viral strategies against human pathogenic mammarenaviruses. In the present work, we present evidence that LCMV multiplication is enhanced in PKR-deficient cells, but pharmacological inhibition of PKR activation unexpectedly resulted in severely restricted propagation of LCMV. Likewise, we document a robust PKR activation in LCMV-infected cells in the absence of detectable levels of dsRNA. Our findings have revealed a complex role of the PKR pathway during LCMV infection and uncovered the activation of PKR as a druggable target for the development of anti-viral drugs against human pathogenic mammarenaviruses.
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Affiliation(s)
- Haydar Witwit
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, California, USA
| | - Roaa Khafaji
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, California, USA
| | - Arul Salaniwal
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, California, USA
| | - Arthur S. Kim
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, California, USA
- Department of Chemistry, The Scripps Research Institute, La Jolla, California, USA
| | - Beatrice Cubitt
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, California, USA
| | | | - Chengjin Ye
- Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Susan R. Weiss
- Department of Microbiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | - Juan Carlos de la Torre
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, California, USA
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4
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Chen CL, Tseng TC, Liu CJ, Kao JH, Chen PJ, Yang WS. Serum RNase L levels in patients with chronic hepatitis B virus infection. Hepatol Res 2024; 54:244-251. [PMID: 37861347 DOI: 10.1111/hepr.13977] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 09/11/2023] [Accepted: 10/02/2023] [Indexed: 10/21/2023]
Abstract
BACKGROUND/AIMS Chronic hepatitis B virus (HBV) infection still poses a major threat to global health. Oligoadenylate synthetase-ribonuclease L (RNase L) antiviral pathway is one of interferon-induced antiviral effectors. The relationship between RNase L and HBV has never been investigated and we aim to examine the serum RNase L levels in patients with different stages of chronic HBV infection. METHODS The patients were enrolled from 1985 to 2000, who had been HBsAg positive for longer than 6 months, at the National Taiwan University Hospital. In total, 426 patients with chronic HBV infection were included in this study, including 135 inactive carriers, 148 cirrhosis, and 143 hepatocellular carcinoma (HCC) cases. RESULTS The RNase L levels increase as the disease severity increases. Higher RNase L levels were associated with higher HBV viral load, and the HBV-RNase L relationship was replaced by the disease severity status when adding disease status into the model. Compared with inactive carriers, the risk of liver cirrhosis was 60-fold (odds ratio = 60.8, 95% confidence interval = 3.49-1061) with the highest quintile of RNase L levels, after the adjustment of HBV DNA. The dose-response trend was statistically significant with quintiles and one increment of RNase L level in relation to liver cirrhosis. Similar results were found when HCC was compared with inactive carriers, while there was no association when compared between liver cirrhosis and HCC. CONCLUSIONS A positive relationship between serum RNase L and HBV viral titers or advanced disease status is uncovered in this study. Further investigation in this area may provide more details of an innate immune response for HBV and opportunity for novel therapeutic strategy.
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Affiliation(s)
- Chi-Ling Chen
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan
- Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
- Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan
| | - Tai-Chung Tseng
- Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Chun-Jen Liu
- Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Jia-Horng Kao
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
- Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Pei-Jer Chen
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
- Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Wei-Shiung Yang
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
- Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
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Ding K, Li H, Tai F, Duan J, Wang Q, Zhai R, Fu H, Ge C, Zheng X. Unraveling the Role of RNase L Knockout in Alleviating Immune Response Activation in Mice Bone Marrow after Irradiation. Int J Mol Sci 2024; 25:2722. [PMID: 38473966 DOI: 10.3390/ijms25052722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 02/09/2024] [Accepted: 02/21/2024] [Indexed: 03/14/2024] Open
Abstract
Ionizing radiation (IR) induces severe hematopoietic injury by causing DNA and RNA damage as well as activating the immune responses, necessitating the development of effective therapeutic strategies. Ribonuclease L (RNase L) as an innate immune response pathway is triggered by exogenous and endogenous abnormal dsRNA under viral infection and dyshomeostasis, thereby activating the immune responses. Thus, we investigated the effect of RNase L on irradiation-induced bone marrow damage using RNase L knockout (RNase L-/-) mice. Phenotypic analysis revealed that RNase L knockout mitigates irradiation-induced injury in the bone marrow. Further investigation into the mechanism of RNase L by RNA-seq, qRT-PCR, and CBA analysis demonstrated that RNase L deficiency counteracts the upregulation of genes related to immune responses induced by irradiation, including cytokines and interferon-stimulated genes. Moreover, RNase L deficiency inhibits the increased levels of immunoglobulins in serum induced by irradiation. These findings indicate that RNase L plays a role in the immune response induced by irradiation in the bone marrow. This study further enhances our understanding of the biological functions of RNase L in the immune response induced by irradiation and offers a novel approach for managing irradiation-induced bone marrow injury through the regulation of RNase L activation.
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Affiliation(s)
- Kexin Ding
- Beijing Key Laboratory for Radiobiology, Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Hujie Li
- Beijing Key Laboratory for Radiobiology, Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Fumin Tai
- Beijing Key Laboratory for Radiobiology, Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Junzhao Duan
- Beijing Key Laboratory for Radiobiology, Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Qiong Wang
- Beijing Key Laboratory for Radiobiology, Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Rui Zhai
- Beijing Key Laboratory for Radiobiology, Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Hanjiang Fu
- Beijing Key Laboratory for Radiobiology, Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Changhui Ge
- Beijing Key Laboratory for Radiobiology, Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Xiaofei Zheng
- Beijing Key Laboratory for Radiobiology, Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
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6
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Xi J, Snieckute G, Asthana A, Gaughan C, Bekker-Jensen S, Silverman RH. Initiation of a ZAKα-dependent Ribotoxic Stress Response by the Innate Immunity Endoribonuclease RNase L. bioRxiv 2023:2023.10.12.562082. [PMID: 37873202 PMCID: PMC10592832 DOI: 10.1101/2023.10.12.562082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
RNase L is a regulated endoribonuclease in higher vertebrates that functions in antiviral innate immunity. Interferons induce OAS enzymes that sense double-stranded RNA of viral origin leading to synthesis of 2',5'-oligoadenylate (2-5A) activators of RNase L. However, it is unknown precisely how RNase L inhibits viral infections. To isolate effects of RNase L from other effects of double-stranded RNA or virus, 2-5A was directly introduced into cells. Here we report that RNase L activation by 2-5A causes a ribotoxic stress response that requires the ribosome-associated MAP3K, ZAKα. Subsequently, the stress-activated protein kinases (SAPK) JNK and p38α are phosphorylated. RNase L activation profoundly altered the transcriptome by widespread depletion of mRNAs associated with different cellular functions, but also by SAPK-dependent induction of inflammatory genes. Our findings show that 2-5A is a ribotoxic stressor that causes RNA damage through RNase L triggering a ZAKα kinase cascade leading to proinflammatory signaling and apoptosis.
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Affiliation(s)
- Jiajia Xi
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH, 44195, USA
| | - Goda Snieckute
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
- Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Abhishek Asthana
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH, 44195, USA
| | - Christina Gaughan
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH, 44195, USA
| | - Simon Bekker-Jensen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
- Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Robert H Silverman
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH, 44195, USA
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Karasik A, Lorenzi HA, DePass AV, Guydosh NR. Endonucleolytic RNA cleavage drives changes in gene expression during the innate immune response. bioRxiv 2023:2023.09.01.555507. [PMID: 37693516 PMCID: PMC10491309 DOI: 10.1101/2023.09.01.555507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Viral infection triggers several dsRNA sensors that lead to changes in gene expression in the cell. One of these sensors activates an endonuclease, RNase L, that cleaves single stranded RNA. However, how the resultant widespread RNA fragmentation affects gene expression is not fully understood. Here we show that this fragmentation induces the Ribotoxic Stress Response via ZAKα, potentially through ribosome collisions. The p38 and JNK pathways that are activated as part of this response promote outcomes that inhibit the virus, such as programmed cell death. We also show that RNase L limits the translation of stress-responsive genes, including antiviral IFIT mRNAs and GADD34 that encodes an antagonist of the Integrated Stress Response. Intriguingly, we found the activity of the generic endonuclease, RNase A, recapitulates many of the same molecular phenotypes as activated RNase L, demonstrating how widespread RNA cleavage can evoke an antiviral program.
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Affiliation(s)
- Agnes Karasik
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Hernan A Lorenzi
- TriLab Bioinformatics Group, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Andrew V DePass
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Nicholas R Guydosh
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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Chen G, Zhao X, Dankovskyy M, Ansah-Zame A, Alghamdi U, Liu D, Wei R, Zhao J, Zhou A. A novel role of RNase L in the development of nonalcoholic steatohepatitis. FASEB J 2023; 37:e23158. [PMID: 37615181 DOI: 10.1096/fj.202300621r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/29/2023] [Accepted: 08/10/2023] [Indexed: 08/25/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and affects about 25% of the population globally. NAFLD has the potential to cause significant liver damage in many patients because it can progress to nonalcoholic steatohepatitis (NASH) and cirrhosis, which substantially increases disease morbidity and mortality. Despite the key role of innate immunity in the disease progression, the underlying molecular and pathogenic mechanisms remain to be elucidated. RNase L is a key enzyme in interferon action against viral infection and displays pleiotropic biological functions such as control of cell proliferation, apoptosis, and autophagy. Recent studies have demonstrated that RNase L is involved in innate immunity. In this study, we revealed that RNase L contributed to the development of NAFLD, which further progressed to NASH in a time-dependent fashion after RNase L wild-type (WT) and knockout mice were fed with a high-fat and high-cholesterol diet. RNase L WT mice showed significantly more severe NASH, evidenced by widespread macro-vesicular steatosis, hepatocyte ballooning degeneration, inflammation, and fibrosis, although physiological and biochemical data indicated that both types of mice developed obesity, hyperglycemia, hypercholesterolemia, dysfunction of the liver, and systemic inflammation at different extents. Further investigation demonstrated that RNase L was responsible for the expression of some key genes in lipid metabolism, inflammation, and fibrosis signaling. Taken together, our results suggest that a novel therapeutic intervention for NAFLD may be developed based on regulating the expression and activity of RNase L.
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Affiliation(s)
- Guanmin Chen
- Department of Chemistry, Cleveland State University, Cleveland, Ohio, USA
| | - Xiaotong Zhao
- Department of Chemistry, Cleveland State University, Cleveland, Ohio, USA
| | - Maksym Dankovskyy
- Department of Chemistry, Cleveland State University, Cleveland, Ohio, USA
| | - Abigail Ansah-Zame
- Department of Chemistry, Cleveland State University, Cleveland, Ohio, USA
| | - Uthman Alghamdi
- Department of Chemistry, Cleveland State University, Cleveland, Ohio, USA
| | - Danting Liu
- Department of Chemistry, Cleveland State University, Cleveland, Ohio, USA
| | - Ruhan Wei
- Department of Chemistry, Cleveland State University, Cleveland, Ohio, USA
| | - Jianjun Zhao
- Department of Cancer Biology, Cleveland Clinic, Cleveland, Ohio, USA
| | - Aimin Zhou
- Department of Chemistry, Cleveland State University, Cleveland, Ohio, USA
- Center for Gene Regulation in Health and Diseases, Cleveland State University, Cleveland, Ohio, USA
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9
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LeBlanc K, Lynch J, Layne C, Vendramelli R, Sloan A, Tailor N, Deschambault Y, Zhang F, Kobasa D, Safronetz D, Xiang Y, Cao J. The Nucleocapsid Proteins of SARS-CoV-2 and Its Close Relative Bat Coronavirus RaTG13 Are Capable of Inhibiting PKR- and RNase L-Mediated Antiviral Pathways. Microbiol Spectr 2023; 11:e0099423. [PMID: 37154717 PMCID: PMC10269842 DOI: 10.1128/spectrum.00994-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 04/11/2023] [Indexed: 05/10/2023] Open
Abstract
Coronaviruses (CoVs), including severe acute respiratory syndrome CoV (SARS-CoV), Middle East respiratory syndrome CoV (MERS-CoV), and SARS-CoV-2, produce double-stranded RNA (dsRNA) that activates antiviral pathways such as PKR and OAS/RNase L. To successfully replicate in hosts, viruses must evade such antiviral pathways. Currently, the mechanism of how SARS-CoV-2 antagonizes dsRNA-activated antiviral pathways is unknown. In this study, we demonstrate that the SARS-CoV-2 nucleocapsid (N) protein, the most abundant viral structural protein, is capable of binding to dsRNA and phosphorylated PKR, inhibiting both the PKR and OAS/RNase L pathways. The N protein of the bat coronavirus (bat-CoV) RaTG13, the closest relative of SARS-CoV-2, has a similar ability to inhibit the human PKR and RNase L antiviral pathways. Via mutagenic analysis, we found that the C-terminal domain (CTD) of the N protein is sufficient for binding dsRNA and inhibiting RNase L activity. Interestingly, while the CTD is also sufficient for binding phosphorylated PKR, the inhibition of PKR antiviral activity requires not only the CTD but also the central linker region (LKR). Thus, our findings demonstrate that the SARS-CoV-2 N protein is capable of antagonizing the two critical antiviral pathways activated by viral dsRNA and that its inhibition of PKR activities requires more than dsRNA binding mediated by the CTD. IMPORTANCE The high transmissibility of SARS-CoV-2 is an important viral factor defining the coronavirus disease 2019 (COVID-19) pandemic. To transmit efficiently, SARS-CoV-2 must be capable of disarming the innate immune response of its host efficiently. Here, we describe that the nucleocapsid protein of SARS-CoV-2 is capable of inhibiting two critical innate antiviral pathways, PKR and OAS/RNase L. Moreover, the counterpart of the closest animal coronavirus relative of SARS-CoV-2, bat-CoV RaTG13, can also inhibit human PKR and OAS/RNase L antiviral activities. Thus, the importance of our discovery for understanding the COVID-19 pandemic is 2-fold. First, the ability of SARS-CoV-2 N to inhibit innate antiviral activity is likely a factor contributing to the transmissibility and pathogenicity of the virus. Second, the bat relative of SARS-CoV-2 has the capacity to inhibit human innate immunity, which thus likely contributed to the establishment of infection in humans. The findings described in this study are valuable for developing novel antivirals and vaccines.
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Affiliation(s)
- Kyle LeBlanc
- Poxviruses and Vaccine Design, Division of Viral Diseases, Directorate of Science Reference and Surveillance, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Jessie Lynch
- Poxviruses and Vaccine Design, Division of Viral Diseases, Directorate of Science Reference and Surveillance, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Christine Layne
- Poxviruses and Vaccine Design, Division of Viral Diseases, Directorate of Science Reference and Surveillance, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Robert Vendramelli
- Special Pathogens, Division of Health Security and Response, Directorate of Scientific Operations and Response, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Angela Sloan
- Special Pathogens, Division of Health Security and Response, Directorate of Scientific Operations and Response, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Nikesh Tailor
- Special Pathogens, Division of Health Security and Response, Directorate of Scientific Operations and Response, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Yvon Deschambault
- Special Pathogens, Division of Health Security and Response, Directorate of Scientific Operations and Response, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Fushun Zhang
- Department of Microbiology and Immunology, The University of Texas Health Science Center, San Antonio, Texas, USA
| | - Darwyn Kobasa
- Special Pathogens, Division of Health Security and Response, Directorate of Scientific Operations and Response, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - David Safronetz
- Special Pathogens, Division of Health Security and Response, Directorate of Scientific Operations and Response, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Yan Xiang
- Department of Microbiology and Immunology, The University of Texas Health Science Center, San Antonio, Texas, USA
| | - Jingxin Cao
- Poxviruses and Vaccine Design, Division of Viral Diseases, Directorate of Science Reference and Surveillance, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
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10
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Dai J, Yi G, Philip AA, Patton JT. Rotavirus NSP1 Subverts the Antiviral Oligoadenylate Synthetase- RNase L Pathway by Inducing RNase L Degradation. mBio 2022; 13:e0299522. [PMID: 36413023 DOI: 10.1128/mbio.02995-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The interferon (IFN)-inducible 2',5'-oligoadenylate synthetase (OAS)-RNase L pathway plays a critical role in antiviral immunity. Group A rotaviruses, including the simian SA11 strain, inhibit this pathway through two activities: an E3-ligase related activity of NSP1 that degrades proteins necessary for IFN signaling, and a phosphodiesterase (PDE) activity of VP3 that hydrolyzes the RNase L-activator 2',5'-oligoadenylate. Unexpectedly, we found that a recombinant (r) SA11 double mutant virus deficient in both activities (rSA11-VP3H797R-NSP1ΔC17) retained the ability to prevent RNase L activation. Mass spectrometry led to the discovery that NSP1 interacts with RNase L in rSA11-infected HT29 cells. This interaction was confirmed through copulldown assay of cells transiently expressing NSP1 and RNase L. Immunoblot analysis showed that infection with wild-type rSA11 virus, rSA11-VP3H797R-NSP1ΔC17 double mutant virus, or single mutant forms of the latter virus all resulted in the depletion of endogenous RNase L. The loss of RNase L was reversed by addition of the neddylation inhibitor MLN4924, but not the proteasome inhibitor MG132. Analysis of additional mutant forms of rSA11 showed that RNase L degradation no longer occurred when either the N-terminal RING domain of NSP1 was mutated or the C-terminal 98 amino acids of NSP1 were deleted. The C-terminal RNase L degradation domain is positioned upstream and is functionally independent of the NSP1 domain necessary for inhibiting IFN expression. Our studies reveal a new role for NSP1 and its E3-ligase related activity as an antagonist of RNase L and uncover a novel virus-mediated strategy of inhibiting the OAS-RNase L pathway. IMPORTANCE For productive infection, rotavirus and other RNA viruses must suppress interferon (IFN) signaling and the expression of IFN-stimulated antiviral gene products. Particularly important is inhibiting the interferon (IFN)-inducible 2',5'-oligoadenylate synthetase (OAS)-RNase L pathway, as activated RNase L can direct the nonspecific degradation of viral and cellular RNAs, thereby blocking viral replication and triggering cell death pathways. In this study, we have discovered that the simian SA11 strain of rotavirus employs a novel strategy of inhibiting the OAS-RNase L pathway. This strategy is mediated by SA11 NSP1, a nonstructural protein that hijacks E3 cullin-RING ligases, causing the ubiquitination and degradation of host proteins essential for IFN induction. Our analysis shows that SA11 NSP1 also recognizes and causes the ubiquitination of RNase L, an activity resulting in depletion of endogenous RNase L. These data raise the possibility of using therapeutics targeting cellular E3 ligases to control rotavirus infections.
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11
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Burke JM. Regulation of ribonucleoprotein condensates by RNase L during viral infection. Wiley Interdiscip Rev RNA 2022:e1770. [PMID: 36479619 DOI: 10.1002/wrna.1770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/10/2022] [Accepted: 11/22/2022] [Indexed: 12/12/2022]
Abstract
In response to viral infection, mammalian cells activate several innate immune pathways to antagonize viral gene expression. Upon recognition of viral double-stranded RNA, protein kinase R (PKR) phosphorylates the alpha subunit of eukaryotic initiation factor 2 (eIF2α) on serine 51. This inhibits canonical translation initiation, which broadly antagonizes viral protein synthesis. It also promotes the assembly of cytoplasmic ribonucleoprotein complexes termed stress granules (SGs). SGs are widely thought to promote cell survival and antiviral signaling. However, co-activation of the OAS/RNase L antiviral pathway inhibits the assembly of SGs and promotes the assembly of an alternative ribonucleoprotein complex termed an RNase L-dependent body (RLB). The formation of RLBs has been observed in response to double-stranded RNA, dengue virus infection, or SARS-CoV-2 infection. Herein, we review the distinct biogenesis pathways and properties of SGs and RLBs, and we provide perspective on their potential functions during the antiviral response. This article is categorized under: RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Turnover and Surveillance > Regulation of RNA Stability RNA Export and Localization > RNA Localization.
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Affiliation(s)
- James M Burke
- Department of Molecular Medicine, University of Florida Scripps Biomedical Research, Jupiter, Florida, USA
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12
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Banerjee S, Smith C, Geballe AP, Rothenburg S, Kitzman JO, Brennan G. Gene amplification acts as a molecular foothold to facilitate cross-species adaptation and evasion of multiple antiviral pathways. Virus Evol 2022; 8:veac105. [PMID: 36483110 PMCID: PMC9724558 DOI: 10.1093/ve/veac105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 10/06/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
Cross-species spillover events are responsible for many of the pandemics in human history including COVID-19; however, the evolutionary mechanisms that enable these events are poorly understood. We have previously modeled this process using a chimeric vaccinia virus expressing the rhesus cytomegalovirus-derived protein kinase R (PKR) antagonist RhTRS1 in place of its native PKR antagonists: E3L and K3L (VACVΔEΔK + RhTRS1). Using this virus, we demonstrated that gene amplification of rhtrs1 occurred early during experimental evolution and was sufficient to fully rescue virus replication in partially resistant African green monkey (AGM) fibroblasts. Notably, this rapid gene amplification also allowed limited virus replication in otherwise completely non-permissive human fibroblasts, suggesting that gene amplification may act as a 'molecular foothold' to facilitate viral adaptation to multiple species. In this study, we demonstrate that there are multiple barriers to VACVΔEΔK + RhTRS1 replication in human cells, mediated by both PKR and ribonuclease L (RNase L). We experimentally evolved three AGM-adapted virus populations in human fibroblasts. Each population adapted to human cells bimodally, via an initial 10-fold increase in replication after only two passages followed by a second 10-fold increase in replication by passage 9. Using our Illumina-based pipeline, we found that some single nucleotide polymorphisms (SNPs) which had evolved during the prior AGM adaptation were rapidly lost, while thirteen single-base substitutions and short indels increased over time, including two SNPs unique to human foreskin fibroblast (HFF)-adapted populations. Many of these changes were associated with components of the viral RNA polymerase, although no variant was shared between all three populations. Taken together, our results demonstrate that rhtrs1 amplification was sufficient to increase viral tropism after passage in an 'intermediate species' and subsequently enabled the virus to adopt different, species-specific adaptive mechanisms to overcome distinct barriers to viral replication in AGM and human cells.
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Affiliation(s)
- Shefali Banerjee
- †Current address for SB: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | | | - Adam P Geballe
- Departments of Human Genetics and Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA,Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | | | - Jacob O Kitzman
- Departments of Microbiology and Medicine, University of Washington, Seattle, WA 98195, USA
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13
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Prangley E, Korennykh A. 2-5A-Mediated decay (2-5AMD): from antiviral defense to control of host RNA. Crit Rev Biochem Mol Biol 2022; 57:477-491. [PMID: 36939319 PMCID: PMC10576847 DOI: 10.1080/10409238.2023.2181308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 10/18/2022] [Accepted: 02/13/2023] [Indexed: 03/21/2023]
Abstract
Mammalian cells are exquisitely sensitive to the presence of double-stranded RNA (dsRNA), a molecule that they interpret as a signal of viral presence requiring immediate attention. Upon sensing dsRNA cells activate the innate immune response, which involves transcriptional mechanisms driving inflammation and secretion of interferons (IFNs) and interferon-stimulated genes (ISGs), as well as synthesis of RNA-like signaling molecules comprised of three or more 2'-5'-linked adenylates (2-5As). 2-5As were discovered some forty years ago and described as IFN-induced inhibitors of protein synthesis. The efforts of many laboratories, aimed at elucidating the molecular mechanism and function of these mysterious RNA-like signaling oligonucleotides, revealed that 2-5A is a specific ligand for the kinase-family endonuclease RNase L. RNase L decays single-stranded RNA (ssRNA) from viruses and mRNAs (as well as other RNAs) from hosts in a process we proposed to call 2-5A-mediated decay (2-5AMD). During recent years it has become increasingly recognized that 2-5AMD is more than a blunt tool of viral RNA destruction, but a pathway deeply integrated into sensing and regulation of endogenous RNAs. Here we present an overview of recently emerged roles of 2-5AMD in host RNA regulation.
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Affiliation(s)
- Eliza Prangley
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Alexei Korennykh
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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14
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Comar CE, Otter CJ, Pfannenstiel J, Doerger E, Renner DM, Tan LH, Perlman S, Cohen NA, Fehr AR, Weiss SR. MERS-CoV endoribonuclease and accessory proteins jointly evade host innate immunity during infection of lung and nasal epithelial cells. Proc Natl Acad Sci U S A 2022; 119:e2123208119. [PMID: 35594398 PMCID: PMC9173776 DOI: 10.1073/pnas.2123208119] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 04/13/2022] [Indexed: 12/25/2022] Open
Abstract
Middle East respiratory syndrome coronavirus (MERS-CoV) emerged into humans in 2012, causing highly lethal respiratory disease. The severity of disease may be, in part, because MERS-CoV is adept at antagonizing early innate immune pathways—interferon (IFN) production and signaling, protein kinase R (PKR), and oligoadenylate synthetase/ribonuclease L (OAS/RNase L)—activated in response to viral double-stranded RNA (dsRNA) generated during genome replication. This is in contrast to severe acute respiratory syndrome CoV-2 (SARS-CoV-2), which we recently reported to activate PKR and RNase L and, to some extent, IFN signaling. We previously found that MERS-CoV accessory proteins NS4a (dsRNA binding protein) and NS4b (phosphodiesterase) could weakly suppress these pathways, but ablation of each had minimal effect on virus replication. Here we investigated the antagonist effects of the conserved coronavirus endoribonuclease (EndoU), in combination with NS4a or NS4b. Inactivation of EndoU catalytic activity alone in a recombinant MERS-CoV caused little if any effect on activation of the innate immune pathways during infection. However, infection with recombinant viruses containing combined mutations with inactivation of EndoU and deletion of NS4a or inactivation of the NS4b phosphodiesterase promoted robust activation of dsRNA-induced innate immune pathways. This resulted in at least tenfold attenuation of replication in human lung–derived A549 and primary nasal cells. Furthermore, replication of these recombinant viruses could be rescued to the level of wild-type MERS-CoV by knockout of host immune mediators MAVS, PKR, or RNase L. Thus, EndoU and accessory proteins NS4a and NS4b together suppress dsRNA-induced innate immunity during MERS-CoV infection in order to optimize viral replication.
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Affiliation(s)
- Courtney E. Comar
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104
- Penn Center for Research on Coronaviruses and Other Emerging Pathogens, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Clayton J. Otter
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104
- Penn Center for Research on Coronaviruses and Other Emerging Pathogens, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Ethan Doerger
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045
| | - David M. Renner
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104
- Penn Center for Research on Coronaviruses and Other Emerging Pathogens, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Li Hui Tan
- Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Philadelphia, PA 19104
| | - Stanley Perlman
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA 52242
| | - Noam A. Cohen
- Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Philadelphia, PA 19104
- Department of Surgery, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA 19104
| | - Anthony R. Fehr
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA 52242
| | - Susan R. Weiss
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104
- Penn Center for Research on Coronaviruses and Other Emerging Pathogens, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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15
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Decker CJ, Burke JM, Mulvaney PK, Parker R. RNA is required for the integrity of multiple nuclear and cytoplasmic membrane-less RNP granules. EMBO J 2022; 41:e110137. [PMID: 35355287 PMCID: PMC9058542 DOI: 10.15252/embj.2021110137] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 03/03/2022] [Accepted: 03/14/2022] [Indexed: 12/22/2022] Open
Abstract
Numerous membrane‐less organelles, composed of a combination of RNA and proteins, are observed in the nucleus and cytoplasm of eukaryotic cells. These RNP granules include stress granules (SGs), processing bodies (PBs), Cajal bodies, and nuclear speckles. An unresolved question is how frequently RNA molecules are required for the integrity of RNP granules in either the nucleus or cytosol. To address this issue, we degraded intracellular RNA in either the cytosol or the nucleus by the activation of RNase L and examined the impact of RNA loss on several RNP granules. We find the majority of RNP granules, including SGs, Cajal bodies, nuclear speckles, and the nucleolus, are altered by the degradation of their RNA components. In contrast, PBs and super‐enhancer complexes were largely not affected by RNA degradation in their respective compartments. RNA degradation overall led to the apparent dissolution of some membrane‐less organelles, whereas others reorganized into structures with altered morphology. These findings highlight a critical and widespread role of RNA in the organization of several RNP granules.
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Affiliation(s)
- Carolyn J Decker
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA
| | - James M Burke
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Patrick K Mulvaney
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Roy Parker
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA.,BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA
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16
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Chitrakar A, Solorio-Kirpichyan K, Prangley E, Rath S, Du J, Korennykh A. Introns encode dsRNAs undetected by RIG-I/MDA5/interferons and sensed via RNase L. Proc Natl Acad Sci U S A 2021; 118:e2102134118. [PMID: 34772806 PMCID: PMC8609619 DOI: 10.1073/pnas.2102134118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2021] [Indexed: 12/24/2022] Open
Abstract
Double-stranded RNA (dsRNA), a hallmark viral material that activates antiviral interferon (IFN) responses, can appear in human cells also in the absence of viruses. We identify phosphorothioate DNAs (PS DNAs) as triggers of such endogenous dsRNA (endo-dsRNA). PS DNAs inhibit decay of nuclear RNAs and induce endo-dsRNA via accumulation of high levels of intronic and intergenic inverted retroelements (IIIR). IIIRs activate endo-dsRNA responses distinct from antiviral defense programs. IIIRs do not turn on transcriptional RIG-I/MDA5/IFN signaling, but they trigger the dsRNA-sensing pathways of OAS3/RNase L and PKR. Thus, nuclear RNA decay and nuclear-cytosolic RNA sorting actively protect from these innate immune responses to self. Our data suggest that the OAS3/RNase L and PKR arms of innate immunity diverge from antiviral IFN responses and monitor nuclear RNA decay by sensing cytosolic escape of IIIRs. OAS3 provides a receptor for IIIRs, whereas RNase L cleaves IIIR-carrying introns and intergenic RNAs.
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Affiliation(s)
- Alisha Chitrakar
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | | | - Eliza Prangley
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Sneha Rath
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Jin Du
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Alexei Korennykh
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
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17
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Burke JM, St Clair LA, Perera R, Parker R. SARS-CoV-2 infection triggers widespread host mRNA decay leading to an mRNA export block. RNA 2021; 27:1318-1329. [PMID: 34315815 PMCID: PMC8522697 DOI: 10.1261/rna.078923.121] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 07/21/2021] [Indexed: 05/16/2023]
Abstract
The transcriptional induction of interferon (IFN) genes is a key feature of the mammalian antiviral response that limits viral replication and dissemination. A hallmark of severe COVID-19 disease caused by SARS-CoV-2 is the low presence of IFN proteins in patient serum despite elevated levels of IFN-encoding mRNAs, indicative of post-transcriptional inhibition of IFN protein production. Here, we performed single-molecule RNA visualization to examine the expression and localization of host mRNAs during SARS-CoV-2 infection. Our data show that the biogenesis of type I and type III IFN mRNAs is inhibited at multiple steps during SARS-CoV-2 infection. First, translocation of the interferon regulatory factor 3 (IRF3) transcription factor to the nucleus is limited in response to SARS-CoV-2, indicating that SARS-CoV-2 inhibits RLR-MAVS signaling and thus weakens transcriptional induction of IFN genes. Second, we observed that IFN mRNAs primarily localize to the site of transcription in most SARS-CoV-2 infected cells, suggesting that SARS-CoV-2 either inhibits the release of IFN mRNAs from their sites of transcription and/or triggers decay of IFN mRNAs in the nucleus upon exiting the site of transcription. Lastly, nuclear-cytoplasmic transport of IFN mRNAs is inhibited during SARS-CoV-2 infection, which we propose is a consequence of widespread degradation of host cytoplasmic basal mRNAs in the early stages of SARS-CoV-2 replication by the SARS-CoV-2 Nsp1 protein, as well as the host antiviral endoribonuclease, RNase L. Importantly, IFN mRNAs can escape SARS-CoV-2-mediated degradation if they reach the cytoplasm, making rescue of mRNA export a viable means for promoting the immune response to SARS-CoV-2.
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Affiliation(s)
- James M Burke
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - Laura A St Clair
- Center for Vector-Borne and Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, USA
- Center for Metabolism of Infectious Diseases, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Rushika Perera
- Center for Vector-Borne and Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, USA
- Center for Metabolism of Infectious Diseases, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Roy Parker
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado 80303, USA
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
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18
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Asthana A, Gaughan C, Dong B, Weiss SR, Silverman RH. Specificity and Mechanism of Coronavirus, Rotavirus, and Mammalian Two-Histidine Phosphoesterases That Antagonize Antiviral Innate Immunity. mBio 2021; 12:e0178121. [PMID: 34372695 DOI: 10.1128/mBio.01781-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The 2′,5′-oligoadenylate (2-5A)-dependent endoribonuclease, RNase L, is a principal mediator of the interferon (IFN) antiviral response. Therefore, the regulation of cellular levels of 2-5A is a key point of control in antiviral innate immunity. Cellular 2-5A levels are determined by IFN-inducible 2′,5′-oligoadenylate synthetases (OASs) and by enzymes that degrade 2-5A. Importantly, many coronaviruses (CoVs) and rotaviruses encode 2-5A-degrading enzymes, thereby antagonizing RNase L and its antiviral effects. A-kinase-anchoring protein 7 (AKAP7), a mammalian counterpart, could possibly limit tissue damage from excessive or prolonged RNase L activation during viral infections or from self-double-stranded RNAs that activate OAS. We show that these enzymes, members of the two-histidine phosphoesterase (2H-PE) superfamily, constitute a subfamily referred here as 2′,5′-PEs. 2′,5′-PEs from the mouse CoV mouse hepatitis virus (MHV) (NS2), Middle East respiratory syndrome coronavirus (MERS-CoV) (NS4b), group A rotavirus (VP3), and mouse (AKAP7) were investigated for their evolutionary relationships and activities. While there was no activity against 3′,5′-oligoribonucleotides, they all cleaved 2′,5′-oligoadenylates efficiently but with variable activity against other 2′,5′-oligonucleotides. The 2′,5′-PEs are shown to be metal ion-independent enzymes that cleave trimer 2-5A (2′,5′-p3A3) producing mono- or diadenylates with 2′,3′-cyclic phosphate termini. Our results suggest that the elimination of 2-5A might be the sole function of viral 2′,5′-PEs, thereby promoting viral escape from innate immunity by preventing or limiting the activation of RNase L.
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19
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Pedersen K, Haupt-Jorgensen M, Krogvold L, Kaur S, Gerling IC, Pociot F, Dahl-Jørgensen K, Buschard K. Genetic predisposition in the 2'-5'A pathway in the development of type 1 diabetes: potential contribution to dysregulation of innate antiviral immunity. Diabetologia 2021; 64:1805-1815. [PMID: 33973017 PMCID: PMC8245375 DOI: 10.1007/s00125-021-05469-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 03/04/2021] [Indexed: 12/14/2022]
Abstract
AIMS/HYPOTHESIS The incidence of type 1 diabetes is increasing more rapidly than can be explained by genetic drift. Viruses may play an important role in the disease, as they seem to activate the 2'-5'-linked oligoadenylate (2'-5'A) pathway of the innate antiviral immune system. Our aim was to investigate this possibility. METHODS Innate antiviral immune pathways were searched for type 1 diabetes-associated polymorphisms using genome-wide association study data. SNPs within ±250kb flanking regions of the transcription start site of 64 genes were examined. These pathways were also investigated for type 1 diabetes-associated RNA expression profiles using laser-dissected islets from two to five tissue sections per donor from the Diabetes Virus Detection (DiViD) study and the network of Pancreatic Organ Donors (nPOD). RESULTS We found 27 novel SNPs in genes nominally associated with type 1 diabetes. Three of those SNPs were located upstream of the 2'-5'A pathway, namely SNP rs4767000 (p = 1.03 × 10-9, OR 1.123), rs1034687 (p = 2.16 × 10-7, OR 0.869) and rs739744 (p = 1.03 × 10-9, OR 1.123). We also identified a large group of dysregulated islet genes in relation to type 1 diabetes, of which two were novel. The most aberrant genes were a group of IFN-stimulated genes. Of those, the following distinct pathways were targeted by the dysregulation (compared with the non-diabetic control group): OAS1 increased by 111% (p < 1.00 × 10-4, 95% CI -0.43, -0.15); MX1 increased by 142% (p < 1.00 × 10-4, 95% CI -0.52, -0.22); and ISG15 increased by 197% (p = 2.00 × 10-4, 95% CI -0.68, -0.18). CONCLUSIONS/INTERPRETATION We identified a genetic predisposition in the 2'-5'A pathway that potentially contributes to dysregulation of the innate antiviral immune system in type 1 diabetes. This study describes a potential role for the 2'-5'A pathway and other components of the innate antiviral immune system in beta cell autoimmunity.
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Affiliation(s)
- Kristina Pedersen
- The Bartholin Institute, Department of Pathology, Rigshospitalet, Copenhagen, Denmark.
| | | | - Lars Krogvold
- Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
- Faculty of Dentistry, University of Oslo, Oslo, Norway
| | | | - Ivan C Gerling
- Department of Medicine, University of Tennessee, Memphis, TN, USA
| | - Flemming Pociot
- Steno Diabetes Center Copenhagen, Gentofte, Denmark
- Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Knut Dahl-Jørgensen
- Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Karsten Buschard
- The Bartholin Institute, Department of Pathology, Rigshospitalet, Copenhagen, Denmark
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20
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Sui C, Jiang D, Wu X, Liu S, Li F, Pan L, Cong X, Li J, Yoo D, Rock DL, Miller LC, Lee C, Du Y, Qi J. Inhibition of Antiviral Innate Immunity by Foot-and-Mouth Disease Virus L pro through Interaction with the N-Terminal Domain of Swine RNase L. J Virol 2021; 95:e0036121. [PMID: 33980594 DOI: 10.1128/JVI.00361-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Foot-and-mouth disease virus (FMDV) is the pathogen of foot-and-mouth disease (FMD), which is a highly contagious disease in cloven-hoofed animals. To survive in the host, FMDV has evolved multiple strategies to antagonize host innate immune responses. In this study, we showed that the leader protease (Lpro) of FMDV, a papain-like proteinase, promoted viral replication by evading the antiviral interferon response through counteracting the 2',5'-oligoadenylate synthetase (OAS)/RNase L system. Specifically, we observed that the titers of Lpro deletion virus were significantly lower than those of wild-type FMDV (FMDV-WT) in cultured cells. Our mechanistic studies demonstrated that Lpro interfered with the OAS/RNase L pathway by interacting with the N-terminal domain of swine RNase L (sRNase L). Remarkably, Lpro of FMDV exhibited species-specific binding to RNase L in that the interaction was observed only in swine cells, not human, monkey, or canine cells. Lastly, we presented evidence that by interacting with sRNase L, FMDV Lpro inhibited cellular apoptosis. Taken together, these results demonstrate a novel mechanism that Lpro utilizes to escape the OAS/RNase L-mediated antiviral defense pathway. IMPORTANCE FMDV is a picornavirus that causes a significant disease in agricultural animals. FMDV has developed diverse strategies to escape the host interferon response. Here, we show that Lpro of FMDV antagonizes the OAS/RNase L pathway, an important interferon effector pathway, by interacting with the N-terminal domain of sRNase L. Interestingly, such a virus-host interaction is species-specific because the interaction is detected only in swine cells, not in human, monkey, or canine cells. Furthermore, Lpro inhibits apoptosis through interacting with sRNase L. This study demonstrates a novel mechanism by which FMDV has evolved to inhibit host innate immune responses.
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Yu H, Bruneau RC, Brennan G, Rothenburg S. Battle Royale: Innate Recognition of Poxviruses and Viral Immune Evasion. Biomedicines 2021; 9:biomedicines9070765. [PMID: 34356829 PMCID: PMC8301327 DOI: 10.3390/biomedicines9070765] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/25/2021] [Accepted: 06/26/2021] [Indexed: 12/17/2022] Open
Abstract
Host pattern recognition receptors (PRRs) sense pathogen-associated molecular patterns (PAMPs), which are molecular signatures shared by different pathogens. Recognition of PAMPs by PRRs initiate innate immune responses via diverse signaling pathways. Over recent decades, advances in our knowledge of innate immune sensing have enhanced our understanding of the host immune response to poxviruses. Multiple PRR families have been implicated in poxvirus detection, mediating the initiation of signaling cascades, activation of transcription factors, and, ultimately, the expression of antiviral effectors. To counteract the host immune defense, poxviruses have evolved a variety of immunomodulators that have diverse strategies to disrupt or circumvent host antiviral responses triggered by PRRs. These interactions influence the outcomes of poxvirus infections. This review focuses on our current knowledge of the roles of PRRs in the recognition of poxviruses, their elicited antiviral effector functions, and how poxviral immunomodulators antagonize PRR-mediated host immune responses.
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Mustafa DAM, Saida L, Latifi D, Wismans LV, de Koning W, Zeneyedpour L, Luider TM, van den Hoogen B, van Eijck CHJ. Rintatolimod Induces Antiviral Activities in Human Pancreatic Cancer Cells: Opening for an Anti-COVID-19 Opportunity in Cancer Patients? Cancers (Basel) 2021; 13:cancers13122896. [PMID: 34207861 PMCID: PMC8227153 DOI: 10.3390/cancers13122896] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 01/08/2023] Open
Abstract
Simple Summary Specific treatment for COVID-19 infections in cancer patients is lacking while the demand for treatment is increasing. Therefore, we explored the effect of Rintatolimod, a Toll-like receptor 3 (TLR3) agonist, on human epithelial cancerous cells. Our results demonstrated that Rintatolimod stimulated an anti-viral effect by producing RNase L that blocks virus replication. Moreover, Rintatolimod activated the innate and the adaptive immune systems by activating a cascade of actions in human cancerous cells. We believe that Rintatolimod should be considered in the treatment regimens of cancer patients who suffer from SARS-CoV-2 infection. Abstract Severe acute respiratory virus-2 (SARS-CoV-2) has spread globally leading to a devastating loss of life. Large registry studies have begun to shed light on the epidemiological and clinical vulnerabilities of cancer patients who succumb to or endure poor outcomes of SARS-CoV-2. Specific treatment for COVID-19 infections in cancer patients is lacking while the demand for treatment is increasing. Therefore, we explored the effect of Rintatolimod (Ampligen®) (AIM ImmunoTech, Ocala, FL, USA), a Toll-like receptor 3 (TLR3) agonist, to treat uninfected human pancreatic cancer cells (HPACs). The direct effect of Rintatolimod was measured by targeted gene expression profiling and by proteomics measurements. Our results show that Rintatolimod induces an antiviral effect in HPACs by inducing RNase-L-dependent and independent pathways of the innate immune system. Treatment with Rintatolimod activated the interferon signaling pathway, leading to the overexpression of several cytokines and chemokines in epithelial cells. Furthermore, Rintatolimod treatment increased the expression of angiogenesis-related genes without promoting fibrosis, which is the main cause of death in patients with COVID-19. We conclude that Rintatolimod could be considered an early additional treatment option for cancer patients who are infected with SARS-CoV-2 to prevent the complicated severity of the disease.
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Affiliation(s)
- Dana A. M. Mustafa
- Department of Pathology, The Tumor Immuno-Pathology (TIP) Laboratory, Erasmus University Medical Center, 3015 Rotterdam, The Netherlands;
| | - Lawlaw Saida
- Department of Surgery, The Tumor Immuno-Pathology (TIP) Laboratory, Erasmus University Medical Center, 3015 Rotterdam, The Netherlands; (L.S.); (D.L.); (L.V.W.)
| | - Diba Latifi
- Department of Surgery, The Tumor Immuno-Pathology (TIP) Laboratory, Erasmus University Medical Center, 3015 Rotterdam, The Netherlands; (L.S.); (D.L.); (L.V.W.)
| | - Leonoor V. Wismans
- Department of Surgery, The Tumor Immuno-Pathology (TIP) Laboratory, Erasmus University Medical Center, 3015 Rotterdam, The Netherlands; (L.S.); (D.L.); (L.V.W.)
| | - Willem de Koning
- Clinical Bioinformatics Unit, Department of Pathology, The Tumor Immuno-Pathology (TIP) Laboratory, Erasmus University Medical Center, 3015 Rotterdam, The Netherlands;
| | - Lona Zeneyedpour
- Department of Neurology, Clinical and Cancer Proteomics, Erasmus University Medical Center, 3015 Rotterdam, The Netherlands; (L.Z.); (T.M.L.)
| | - Theo M. Luider
- Department of Neurology, Clinical and Cancer Proteomics, Erasmus University Medical Center, 3015 Rotterdam, The Netherlands; (L.Z.); (T.M.L.)
| | | | - Casper H. J. van Eijck
- Department of Surgery, The Tumor Immuno-Pathology (TIP) Laboratory, Erasmus University Medical Center, 3015 Rotterdam, The Netherlands; (L.S.); (D.L.); (L.V.W.)
- Correspondence: ; Tel.: +31-1-7044329
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Whelan JN, Parenti NA, Hatterschide J, Renner DM, Li Y, Reyes HM, Dong B, Perez ER, Silverman RH, Weiss SR. Zika virus employs the host antiviral RNase L protein to support replication factory assembly. Proc Natl Acad Sci U S A 2021; 118:e2101713118. [PMID: 34031250 DOI: 10.1073/pnas.2101713118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Infection with the flavivirus Zika virus (ZIKV) can result in tissue tropism, disease outcome, and route of transmission distinct from those of other flaviviruses; therefore, we aimed to identify host machinery that exclusively promotes the ZIKV replication cycle, which can inform on differences at the organismal level. We previously reported that deletion of the host antiviral ribonuclease L (RNase L) protein decreases ZIKV production. Canonical RNase L catalytic activity typically restricts viral infection, including that of the flavivirus dengue virus (DENV), suggesting an unconventional, proviral RNase L function during ZIKV infection. In this study, we reveal that an inactive form of RNase L supports assembly of ZIKV replication factories (RFs) to enhance infectious virus production. Compared with the densely concentrated ZIKV RFs generated with RNase L present, deletion of RNase L induced broader subcellular distribution of ZIKV replication intermediate double-stranded RNA (dsRNA) and NS3 protease, two constituents of ZIKV RFs. An inactive form of RNase L was sufficient to contain ZIKV genome and dsRNA within a smaller RF area, which subsequently increased infectious ZIKV release from the cell. Inactive RNase L can interact with cytoskeleton, and flaviviruses remodel cytoskeleton to construct RFs. Thus, we used the microtubule-stabilization drug paclitaxel to demonstrate that ZIKV repurposes RNase L to facilitate the cytoskeleton rearrangements required for proper generation of RFs. During infection with flaviviruses DENV or West Nile Kunjin virus, inactive RNase L did not improve virus production, suggesting that a proviral RNase L role is not a general feature of all flavivirus infections.
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Ramnani B, Manivannan P, Jaggernauth S, Malathi K. ABCE1 Regulates RNase L-Induced Autophagy during Viral Infections. Viruses 2021; 13:v13020315. [PMID: 33670646 PMCID: PMC7922175 DOI: 10.3390/v13020315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/14/2021] [Accepted: 02/16/2021] [Indexed: 12/15/2022] Open
Abstract
Host response to a viral infection includes the production of type I interferon (IFN) and the induction of interferon-stimulated genes that have broad antiviral effects. One of the key antiviral effectors is the IFN-inducible oligoadenylate synthetase/ribonuclease L (OAS/RNase L) pathway, which is activated by double-stranded RNA to synthesize unique oligoadenylates, 2-5A, to activate RNase L. RNase L exerts an antiviral effect by cleaving diverse RNA substrates, limiting viral replication; many viruses have evolved mechanisms to counteract the OAS/RNase L pathway. Here, we show that the ATP-binding cassette E1 (ABCE1) transporter, identified as an inhibitor of RNase L, regulates RNase L activity and RNase L-induced autophagy during viral infections. ABCE1 knockdown cells show increased RNase L activity when activated by 2-5A. Compared to parental cells, the autophagy-inducing activity of RNase L in ABCE1-depleted cells is enhanced with early onset. RNase L activation in ABCE1-depleted cells inhibits cellular proliferation and sensitizes cells to apoptosis. Increased activity of caspase-3 causes premature cleavage of autophagy protein, Beclin-1, promoting a switch from autophagy to apoptosis. ABCE1 regulates autophagy during EMCV infection, and enhanced autophagy in ABCE1 knockdown cells promotes EMCV replication. We identify ABCE1 as a host protein that inhibits the OAS/RNase L pathway by regulating RNase L activity, potentially affecting antiviral effects.
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Guo Y, Parker JSL. The Paradoxes of Viral mRNA Translation during Mammalian Orthoreovirus Infection. Viruses 2021; 13:275. [PMID: 33670092 DOI: 10.3390/v13020275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 02/06/2023] Open
Abstract
De novo viral protein synthesis following entry into host cells is essential for viral replication. As a consequence, viruses have evolved mechanisms to engage the host translational machinery while at the same time avoiding or counteracting host defenses that act to repress translation. Mammalian orthoreoviruses are dsRNA-containing viruses whose mRNAs were used as models for early investigations into the mechanisms that underpin the recognition and engagement of eukaryotic mRNAs by host cell ribosomes. However, there remain many unanswered questions and paradoxes regarding translation of reoviral mRNAs in the context of infection. This review summarizes the current state of knowledge about reovirus translation, identifies key unanswered questions, and proposes possible pathways toward a better understanding of reovirus translation.
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Daou S, Talukdar M, Tang J, Dong B, Banerjee S, Li Y, Duffy NM, Ogunjimi AA, Gaughan C, Jha BK, Gish G, Tavernier N, Mao D, Weiss SR, Huang H, Silverman RH, Sicheri F. A phenolic small molecule inhibitor of RNase L prevents cell death from ADAR1 deficiency. Proc Natl Acad Sci U S A 2020; 117:24802-12. [PMID: 32958664 DOI: 10.1073/pnas.2006883117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The OAS–RNase L system is an innate immunity pathway activated by viral infection. Viral dsRNA stimulates OAS enzymes to produce short 2′,5′-oligoadenylates (2-5A) that activate RNase L, resulting in cleavage of single-stranded (ss) RNA. We discovered a small-molecule inhibitor of RNase L that rescues the toxic phenotype of cells deficient in the dsRNA-editing enzyme ADAR1. ADAR1 destabilizes dsRNA to prevent OAS activity. ADAR1 mutations are responsible for a subset of cases of Aicardi-Goutières syndrome (AGS), a severe neurodevelopmental and inflammatory genetic disease of children with no effective medical therapy. We posit that an RNase L inhibitor may have utility against cases of AGS in which RNase L is activated and other indications where overactivation of RNase L is harmful. The oligoadenylate synthetase (OAS)–RNase L system is an IFN-inducible antiviral pathway activated by viral infection. Viral double-stranded (ds) RNA activates OAS isoforms that synthesize the second messenger 2-5A, which binds and activates the pseudokinase-endoribonuclease RNase L. In cells, OAS activation is tamped down by ADAR1, an adenosine deaminase that destabilizes dsRNA. Mutation of ADAR1 is one cause of Aicardi-Goutières syndrome (AGS), an interferonopathy in children. ADAR1 deficiency in human cells can lead to RNase L activation and subsequent cell death. To evaluate RNase L as a possible therapeutic target for AGS, we sought to identify small-molecule inhibitors of RNase L. A 500-compound library of protein kinase inhibitors was screened for modulators of RNase L activity in vitro. We identified ellagic acid (EA) as a hit with 10-fold higher selectivity against RNase L compared with its nearest paralog, IRE1. SAR analysis identified valoneic acid dilactone (VAL) as a superior inhibitor of RNase L, with 100-fold selectivity over IRE1. Mechanism-of-action analysis indicated that EA and VAL do not bind to the pseudokinase domain of RNase L despite acting as ATP competitive inhibitors of the protein kinase CK2. VAL is nontoxic and functional in cells, although with a 1,000-fold decrease in potency, as measured by RNA cleavage activity in response to treatment with dsRNA activator or by rescue of cell lethality resulting from self dsRNA induced by ADAR1 deficiency. These studies lay the foundation for understanding novel modes of regulating RNase L function using small-molecule inhibitors and avenues of therapeutic potential.
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Nakahama T, Kawahara Y. Adenosine-to-inosine RNA editing in the immune system: friend or foe? Cell Mol Life Sci 2020; 77:2931-2948. [PMID: 31996954 DOI: 10.1007/s00018-020-03466-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 12/27/2019] [Accepted: 01/14/2020] [Indexed: 12/19/2022]
Abstract
Our body expresses sensors to detect pathogens through the recognition of expressed molecules, including nucleic acids, lipids, and proteins, while immune tolerance prevents an overreaction with self and the development of autoimmune disease. Adenosine (A)-to-inosine (I) RNA editing, catalyzed by adenosine deaminases acting on RNA (ADARs), is a post-transcriptional modification that can potentially occur at over 100 million sites in the human genome, mainly in Alu repetitive elements that preferentially form a double-stranded RNA (dsRNA) structure. A-to-I conversion within dsRNA, which may induce a structural change, is required to escape from the host immune system, given that endogenous dsRNAs transcribed from Alu repetitive elements are potentially recognized by melanoma differentiation-associated protein 5 (MDA5) as non-self. Of note, loss-of-function mutations in the ADAR1 gene cause Aicardi-Goutières syndrome, a congenital autoimmune disease characterized by encephalopathy and a type I interferon (IFN) signature. However, the loss of ADAR1 in cancer cells with an IFN signature induces lethality via the activation of protein kinase R in addition to MDA5. This makes cells more sensitive to immunotherapy, highlighting the opposing immune status of autoimmune diseases (overreaction) and cancer (tolerance). In this review, we provide an overview of insights into two opposing aspects of RNA editing that functions as a modulator of the immune system in autoimmune diseases and 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
| | - Yukio Kawahara
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan.
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Manivannan P, Siddiqui MA, Malathi K. RNase L Amplifies Interferon Signaling by Inducing Protein Kinase R-Mediated Antiviral Stress Granules. J Virol 2020; 94:e00205-20. [PMID: 32295917 DOI: 10.1128/JVI.00205-20] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 04/08/2020] [Indexed: 02/07/2023] Open
Abstract
Double-stranded RNAs produced during viral infections serve as pathogen-associated molecular patterns (PAMPs) and bind pattern recognition receptors to stimulate IFN production. RNase L is an IFN-regulated endoribonuclease that is activated in virus-infected cells and cleaves single-stranded viral and cellular RNAs. The RNase L-cleaved dsRNAs signal to Rig-like helicases to amplify IFN production. This study identifies a novel role of antiviral stress granules induced by RNase L as an antiviral signaling hub to coordinate the RNA ligands with cognate receptors to mount an effective host response during viral infections. Virus infection leads to activation of the interferon (IFN)-induced endoribonuclease RNase L, which results in degradation of viral and cellular RNAs. Both cellular and viral RNA cleavage products of RNase L bind pattern recognition receptors (PRRs), like retinoic acid-inducible I (Rig-I) and melanoma differentiation-associated protein 5 (MDA5), to further amplify IFN production and antiviral response. Although much is known about the mechanics of ligand binding and PRR activation, how cells coordinate RNA sensing with signaling response and interferon production remains unclear. We show that RNA cleavage products of RNase L activity induce the formation of antiviral stress granules (avSGs) by regulating activation of double-stranded RNA (dsRNA)-dependent protein kinase R (PKR) and recruit the antiviral proteins Rig-I, PKR, OAS, and RNase L to avSGs. Biochemical analysis of purified avSGs showed interaction of a key stress granule protein, G3BP1, with only PKR and Rig-I and not with OAS or RNase L. AvSG assembly during RNase L activation is required for IRF3-mediated IFN production, but not IFN signaling or proinflammatory cytokine induction. Consequently, cells lacking avSG formation or RNase L signaling produced less IFN and showed higher susceptibility during Sendai virus infection, demonstrating the importance of avSGs in RNase L-mediated host defense. We propose a role during viral infection for RNase L-cleaved RNAs in inducing avSGs containing antiviral proteins to provide a platform for efficient interaction of RNA ligands with pattern recognition receptors to enhance IFN production to mount an effective antiviral response. IMPORTANCE Double-stranded RNAs produced during viral infections serve as pathogen-associated molecular patterns (PAMPs) and bind pattern recognition receptors to stimulate IFN production. RNase L is an IFN-regulated endoribonuclease that is activated in virus-infected cells and cleaves single-stranded viral and cellular RNAs. The RNase L-cleaved dsRNAs signal to Rig-like helicases to amplify IFN production. This study identifies a novel role of antiviral stress granules induced by RNase L as an antiviral signaling hub to coordinate the RNA ligands with cognate receptors to mount an effective host response during viral infections.
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29
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Wei R, Chen G, Algehainy N, Zeng C, Liu C, Liu H, Liu W, Stacey D, Zhou A. RNase L Is Involved in Liposaccharide-Induced Lung Inflammation. Viruses 2020; 12:v12010073. [PMID: 31936150 PMCID: PMC7019736 DOI: 10.3390/v12010073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 12/30/2019] [Accepted: 01/01/2020] [Indexed: 01/11/2023] Open
Abstract
RNase L mediates interferon (IFN) function during viral infection and cell proliferation. Furthermore, the role of RNase L in the regulation of gene expression, cell apoptosis, autophagy, and innate immunity has been well established in the last decade. Tissue distribution reveals that RNase L is highly expressed in the lung and other organs. However, the physiological roles of RNase L in the lung are largely unknown. In this study, we found that polysaccharide (LPS)-induced acute lung injury (ALI) was remarkably intensified in mice deficient in RNase L compared to wild type mice under the same condition. Furthermore, we found that RNase L mediated the TLR4 signaling pathway, and regulated the expression of various pro- and anti-inflammatory genes in the lung tissue and blood. Most importantly, RNase L function in macrophages during LPS stimulation may be independent of the 2-5A system. These findings demonstrate a novel role of RNase L in the immune response via an atypical molecular mechanism.
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Affiliation(s)
- Ruhan Wei
- Clinical Chemistry Program, Department of Chemistry, Cleveland State University, Cleveland, OH 44115, USA; (R.W.); (G.C.); (N.A.); (C.Z.); (H.L.)
| | - Guanmin Chen
- Clinical Chemistry Program, Department of Chemistry, Cleveland State University, Cleveland, OH 44115, USA; (R.W.); (G.C.); (N.A.); (C.Z.); (H.L.)
| | - Naseh Algehainy
- Clinical Chemistry Program, Department of Chemistry, Cleveland State University, Cleveland, OH 44115, USA; (R.W.); (G.C.); (N.A.); (C.Z.); (H.L.)
| | - Chun Zeng
- Clinical Chemistry Program, Department of Chemistry, Cleveland State University, Cleveland, OH 44115, USA; (R.W.); (G.C.); (N.A.); (C.Z.); (H.L.)
| | - Chunfang Liu
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China;
| | - Hongli Liu
- Clinical Chemistry Program, Department of Chemistry, Cleveland State University, Cleveland, OH 44115, USA; (R.W.); (G.C.); (N.A.); (C.Z.); (H.L.)
| | - Wendy Liu
- Department of Pathology, University Hospitals Cleveland Medical Center, Cleveland, OH 44115, USA;
| | - Dennis Stacey
- Department of BGES, Cleveland State University, Cleveland, OH 44115, USA;
| | - Aimin Zhou
- Clinical Chemistry Program, Department of Chemistry, Cleveland State University, Cleveland, OH 44115, USA; (R.W.); (G.C.); (N.A.); (C.Z.); (H.L.)
- Center for Gene Regulation in Health and Diseases, Cleveland State University, Cleveland, OH 44115, USA
- Correspondence: ; Tel.: +1-216-687-2416; Fax: +1-216-687-9298
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Madden JC Jr, Cui D, Brinton MA. RNase L Antiviral Activity Is Not a Critical Component of the Oas1b-Mediated Flavivirus Resistance Phenotype. J Virol 2019; 93:e00946-19. [PMID: 31462564 DOI: 10.1128/JVI.00946-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/21/2019] [Indexed: 01/09/2023] Open
Abstract
In mice, resistance to central nervous system (CNS) disease induced by members of the genus Flavivirus is conferred by an allele of the 2'-5' oligoadenylate synthetase 1b gene that encodes the inactive full-length protein (Oas1b-FL). The susceptibility allele encodes a C-terminally truncated protein (Oas1b-tr). We show that the efficiency of neuron infection in the brains of resistant and susceptible mice is similar after an intracranial inoculation of two flaviviruses, but amplification of viral proteins and double-stranded RNA (dsRNA) is inhibited in infected neurons in resistant mouse brains at later times. Active OAS proteins detect cytoplasmic dsRNA and synthesize short 2'-5'-linked oligoadenylates (2'-5'A) that interact with the latent endonuclease RNase L, causing it to dimerize and cleave single-stranded RNAs. To evaluate the contribution of RNase L to the resistance phenotype in vivo, we created a line of resistant RNase L-/- mice. Evidence of RNase L activation in infected RNase L+/+ mice was indicated by higher levels of viral RNA in the brains of infected RNase L-/- mice. Activation of type I interferon (IFN) signaling was detected in both resistant and susceptible brains, but Oas1a and Oas1b mRNA levels were lower in RNase L+/+ mice of both types, suggesting that activated RNase L also has a proflaviviral effect. Inhibition of virus replication was robust in resistant RNase L-/- mice, indicating that activated RNase L is not a critical factor in mediating this phenotype.IMPORTANCE The mouse genome encodes a family of Oas proteins that synthesize 2'-5'A in response to dsRNA. 2'-5'A activates the endonuclease RNase L to cleave single-stranded viral and cellular RNAs. The inactive, full-length Oas1b protein confers flavivirus-specific disease resistance. Although similar numbers of neurons were infected in resistant and susceptible brains after an intracranial virus infection, viral components amplified only in susceptible brains at later times. A line of resistant RNase L-/- mice was used to evaluate the contribution of RNase L to the resistance phenotype in vivo Activation of RNase L antiviral activity by flavivirus infection was indicated by increased viral RNA levels in the brains of RNase L-/- mice. Oas1a and Oas1b mRNA levels were higher in infected RNase L-/- mice, indicating that activated RNase L also have a proflaviviral affect. However, the resistance phenotype was equally robust in RNase L-/- and RNase L+/+ mice.
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Yin H, Jiang Z, Wang S, Zhang P. Actinomycin D-Activated RNase L Promotes H2A.X/H2B-Mediated DNA Damage and Apoptosis in Lung Cancer Cells. Front Oncol 2019; 9:1086. [PMID: 31750234 PMCID: PMC6842983 DOI: 10.3389/fonc.2019.01086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 10/02/2019] [Indexed: 01/24/2023] Open
Abstract
Background: Chemotherapy is an essential component for comprehensive cancer treatment, while drug resistance usually fails therapy. DNA repair mechanism of cancer cells restrains the efficacy of therapeutics targeting DNA damage. Investigating target-inducing irreversible cell death of cancer cells may be promising. Methods: The present study used lung cancer cell lines, transplanted tumor model of lung cancers derived from patients with lung adenocarcinoma, and molecular experiments to investigate the effects and mechanism of Actinomycin D (Act D)-activated RNase L in lung canceers. Results: We report that RNase L, when activated by Act D, induces Caspase-3/PARP activation. The latter further enables ROCK-1 to initiate subsequent membrane blebbing and, meanwhile, result in DNA cleavage and cell cycle arrest mediated by H2A.X/H2B-p21 axis, leading to irreversible DNA damage, and apoptosis of lung cancer cells. The present study highlighted the crucial role of RNase L in triggering apoptosis mechanism through the Caspase-3/ROCK-1/PARP/H2A.X+H2B/p21 axis during Act D treatment. Moreover, activation of RNase L suppressed the tumor formation and the induction of lung cancer stem cells. Conclusion: This study unveiled the regulatory function and related mechanism of RNase L and implied the promising application of therapeutics targeting RNase L in lung cancer.
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Affiliation(s)
- Huijing Yin
- Cancer Institute, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical School, Fudan University, Shanghai, China.,Department of Immunology, Tongji University School of Medicine, Shanghai, China
| | - Zhengyu Jiang
- Faculty of Anesthesiology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Shuoer Wang
- Cancer Institute, Fudan University Shanghai Cancer Center, Shanghai, China.,Central Laboratory, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China
| | - Ping Zhang
- Cancer Institute, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical School, Fudan University, Shanghai, China
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Burke JM, Moon SL, Matheny T, Parker R. RNase L Reprograms Translation by Widespread mRNA Turnover Escaped by Antiviral mRNAs. Mol Cell 2019; 75:1203-1217.e5. [PMID: 31494035 DOI: 10.1016/j.molcel.2019.07.029] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 06/13/2019] [Accepted: 07/18/2019] [Indexed: 12/27/2022]
Abstract
In response to foreign and endogenous double-stranded RNA (dsRNA), protein kinase R (PKR) and ribonuclease L (RNase L) reprogram translation in mammalian cells. PKR inhibits translation initiation through eIF2α phosphorylation, which triggers stress granule (SG) formation and promotes translation of stress responsive mRNAs. The mechanisms of RNase L-driven translation repression, its contribution to SG assembly, and its regulation of dsRNA stress-induced mRNAs are unknown. We demonstrate that RNase L drives translational shut-off in response to dsRNA by promoting widespread turnover of mRNAs. This alters stress granule assembly and reprograms translation by allowing translation of mRNAs resistant to RNase L degradation, including numerous antiviral mRNAs such as interferon (IFN)-β. Individual cells differentially activate dsRNA responses revealing variation that can affect cellular outcomes. This identifies bulk mRNA degradation and the resistance of antiviral mRNAs as the mechanism by which RNase L reprograms translation in response to dsRNA.
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Rath S, Prangley E, Donovan J, Demarest K, Wingreen NS, Meir Y, Korennykh A. Concerted 2-5A-Mediated mRNA Decay and Transcription Reprogram Protein Synthesis in the dsRNA Response. Mol Cell 2019; 75:1218-1228.e6. [PMID: 31494033 DOI: 10.1016/j.molcel.2019.07.027] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 06/13/2019] [Accepted: 07/16/2019] [Indexed: 01/09/2023]
Abstract
Viral and endogenous double-stranded RNA (dsRNA) is a potent trigger for programmed RNA degradation by the 2-5A/RNase L complex in cells of all mammals. This 2-5A-mediated decay (2-5AMD) is a conserved stress response switching global protein synthesis from homeostasis to production of interferons (IFNs). To understand this mechanism, we examined 2-5AMD in human cells and found that it triggers polysome collapse characteristic of inhibited translation initiation. We determined that translation initiation complexes and ribosomes purified from translation-arrested cells remain functional. However, spike-in RNA sequencing (RNA-seq) revealed cell-wide decay of basal mRNAs accompanied by rapid accumulation of mRNAs encoding innate immune proteins. Our data attribute this 2-5AMD evasion to better stability of defense mRNAs and positive feedback in the IFN response amplified by RNase L-resistant molecules. We conclude that 2-5AMD and transcription act in concert to refill mammalian cells with defense mRNAs, thereby "prioritizing" the synthesis of innate immune proteins.
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Affiliation(s)
- Sneha Rath
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Eliza Prangley
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Jesse Donovan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Kaitlin Demarest
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Ned S Wingreen
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Yigal Meir
- Department of Physics, Ben Gurion University, Beer-Sheva 84105, Israel
| | - Alexei Korennykh
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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Whelan JN, Li Y, Silverman RH, Weiss SR. Zika Virus Production Is Resistant to RNase L Antiviral Activity. J Virol 2019; 93:e00313-19. [PMID: 31142667 DOI: 10.1128/JVI.00313-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/24/2019] [Indexed: 12/18/2022] Open
Abstract
There is currently no knowledge of how the emerging human pathogen Zika virus (ZIKV) interacts with the antiviral endoribonuclease L (RNase L) pathway during infection. Since activation of RNase L during infection typically limits virus production dramatically, we used CRISPR-Cas9 gene editing technology to knockout (KO) targeted host genes involved in the RNase L pathway to evaluate the effects of RNase L on ZIKV infection in human A549 cells. RNase L was activated in response to ZIKV infection, which degraded ZIKV genomic RNA. Surprisingly, despite viral genome reduction, RNase L activity did not reduce ZIKV infectious titers. In contrast, both the flavivirus dengue virus and the alphavirus Sindbis virus replicated to significantly higher titers in RNase L KO cells compared to wild-type (WT) cells. Using MAVS/RNase L double KO cells, we demonstrated that the absence of increased ZIKV production in RNase L KO cells was not due to compensation by enhanced type I interferon transcripts to thus inhibit virus production. Finally, when synthetic double-stranded RNA was detected by OAS3 to induce RNase L antiviral activity prior to ZIKV infection, we observed reduced ZIKV replication factory formation, as well as a 42-fold reduction in virus yield in WT but not RNase L KO cells. This study proposes that ZIKV evades RNase L antiviral activity by generating a viral genome reservoir protected from RNase L cleavage during early infection, allowing for sufficient virus production before RNase L activation is detectable.IMPORTANCE With the onset of the 2015 ZIKV outbreak, ZIKV pathogenesis has been of extreme global public health interest, and a better understanding of interactions with the host would provide insight into molecular mechanisms driving the severe neurological outcomes of ZIKV disease. Here is the initial report on the relationship between ZIKV and the host oligoadenylate synthetase-RNase L (OAS-RNase L) system, a potent antiviral pathway effective at restricting replication of diverse viruses. Our study elucidated a unique mechanism whereby ZIKV production is impervious to antiviral RNase L activity, through a mechanism of viral RNA protection that is not mimicked during infection with numerous other RNase L-activating viruses, thus identifying a distinct replication strategy potentially important for ZIKV pathogenesis.
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35
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Manivannan P, Reddy V, Mukherjee S, Clark KN, Malathi K. RNase L Induces Expression of A Novel Serine/Threonine Protein Kinase, DRAK1, to Promote Apoptosis. Int J Mol Sci 2019; 20:E3535. [PMID: 31330998 PMCID: PMC6679093 DOI: 10.3390/ijms20143535] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 07/12/2019] [Accepted: 07/17/2019] [Indexed: 11/28/2022] Open
Abstract
Apoptosis of virus-infected cells is an effective antiviral mechanism in addition to interferon induction to establish antiviral state to restrict virus spread. The interferon-inducible 2'-5' oligoadenylate synthetase/RNase L pathway results in activation of RNase L in response to double stranded RNA and cleaves diverse RNA substrates to amplify interferon induction and promote apoptosis. Here we show that RNase L induces expression of Death-associated protein kinase-Related Apoptosis-inducing protein Kinase 1 (DRAK1), a member of the death-associated protein kinase family and interferon-signaling pathway is required for induction. Overexpression of DRAK1 triggers apoptosis in the absence of RNase L activation by activating c-Jun N-terminal kinase (JNK), translocation of BCL2 Associated X (Bax) to the mitochondria accompanied by cytochrome C release and loss of mitochondrial membrane potential promoting cleavage of caspase 3 and Poly(ADP-Ribose) Polymerase 1 (PARP). Inhibitors of JNK and caspase 3 promote survival of DRAK1 overexpressing cells demonstrating an important role of JNK signaling pathway in DRAK1-mediated apoptosis. DRAK1 mutant proteins that lack kinase activity or nuclear localization fail to induce apoptosis highlighting the importance of cellular localization and kinase function in promoting cell death. Our studies identify DRAK1 as a mediator of RNase L-induced apoptosis.
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Affiliation(s)
- Praveen Manivannan
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
| | - Vidita Reddy
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
| | - Sushovita Mukherjee
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
| | - Kirsten Neytania Clark
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
| | - Krishnamurthy Malathi
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA.
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36
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Wiatrek DM, Candela ME, Sedmík J, Oppelt J, Keegan LP, O'Connell MA. Activation of innate immunity by mitochondrial dsRNA in mouse cells lacking p53 protein. RNA 2019; 25:713-726. [PMID: 30894411 PMCID: PMC6521600 DOI: 10.1261/rna.069625.118] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 03/16/2019] [Indexed: 05/27/2023]
Abstract
Viral and cellular double-stranded RNA (dsRNA) is recognized by cytosolic innate immune sensors, including RIG-I-like receptors. Some cytoplasmic dsRNA is commonly present in cells, and one source is mitochondrial dsRNA, which results from bidirectional transcription of mitochondrial DNA (mtDNA). Here we demonstrate that Trp53 mutant mouse embryonic fibroblasts contain immune-stimulating endogenous dsRNA of mitochondrial origin. We show that the immune response induced by this dsRNA is mediated via RIG-I-like receptors and leads to the expression of type I interferon and proinflammatory cytokine genes. The mitochondrial dsRNA is cleaved by RNase L, which cleaves all cellular RNA including mitochondrial mRNAs, increasing activation of RIG-I-like receptors. When mitochondrial transcription is interrupted there is a subsequent decrease in this immune-stimulatory dsRNA. Our results reveal that the role of p53 in innate immunity is even more versatile and complex than previously anticipated. Our study, therefore, sheds new light on the role of endogenous RNA in diseases featuring aberrant immune responses.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Adenosine Deaminase/deficiency
- Adenosine Deaminase/genetics
- Adenosine Deaminase/immunology
- Animals
- Carrier Proteins/genetics
- Carrier Proteins/immunology
- DEAD Box Protein 58/genetics
- DEAD Box Protein 58/immunology
- Embryo, Mammalian
- Endoribonucleases/genetics
- Endoribonucleases/immunology
- Fibroblasts/cytology
- Fibroblasts/immunology
- Immunity, Innate/genetics
- Interferon Regulatory Factor-7/genetics
- Interferon Regulatory Factor-7/immunology
- Interferon-Induced Helicase, IFIH1/genetics
- Interferon-Induced Helicase, IFIH1/immunology
- Intracellular Signaling Peptides and Proteins
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Proteins/genetics
- Proteins/immunology
- RNA, Double-Stranded/genetics
- RNA, Double-Stranded/immunology
- RNA, Mitochondrial/genetics
- RNA, Mitochondrial/immunology
- RNA-Binding Proteins
- Transcription, Genetic
- Transfection
- Tumor Suppressor Protein p53/deficiency
- Tumor Suppressor Protein p53/genetics
- Tumor Suppressor Protein p53/immunology
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Affiliation(s)
| | | | - Jiří Sedmík
- CEITEC Masaryk University, 625 00 Brno, Czech Republic
| | - Jan Oppelt
- CEITEC Masaryk University, 625 00 Brno, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, 625 00 Brno, Czech Republic
| | - Liam P Keegan
- CEITEC Masaryk University, 625 00 Brno, Czech Republic
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Abstract
Circular RNAs (circRNAs) from back-splicing have been found in every cell and tissue. By binding to miRNAs and proteins or even by encoding small proteins, circRNAs are now emerging as important regulators in modulating transcription, RNA splicing and interference. The highlighted discovery reports an important role of circRNAs in antiviral innate immunity by binding PKR as PKR inhibitors. Rapid degradation of circRNAs by activated RNase L from virus infection or poly I:C stimulation is required to free PKR for its activation. Systemic lupus erythematosus patients remark with circRNA reduction and aberrant PKR activation.
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Affiliation(s)
- Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD USA
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38
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Zhong Y, Pan B, Zhu J, Fu H, Zheng X. RNase L facilitates the repair of DNA double-strand breaks through the nonhomologous end-joining pathway. FEBS Lett 2019; 593:1190-1200. [PMID: 31062340 DOI: 10.1002/1873-3468.13426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 03/18/2019] [Accepted: 03/24/2019] [Indexed: 11/08/2022]
Abstract
RNA molecules have been found to play important roles in DNA double-strand break (DSB) repair, but the exact underlying mechanism remains unclear. Here, we aimed to clarify the function of RNase L, an important ribonuclease in the immune system of vertebrates, in DSB repair. Knockdown of RNase L reduces cell survival after induction of DSBs by ionizing radiation or camptothecin and causes a significant decrease in DSB repair, as evidenced by an increase in the extent of phosphorylation of histone H2AX on Ser139 (γH2AX) and γH2AX nuclear foci formation. Thus, our findings indicate that RNase L interacts with the core factors involved in DNA end joining, such as XRCC4 and Lig4, and facilitates DSB repair through the nonhomologous end-joining pathway.
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Affiliation(s)
- Yiran Zhong
- Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, China
| | - Bingxin Pan
- Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, China.,Anhui Medical University, Hefei, China
| | - Jie Zhu
- Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, China
| | - Hanjiang Fu
- Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, China
| | - Xiaofei Zheng
- Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, China
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39
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Banerjee S, Gusho E, Gaughan C, Dong B, Gu X, Holvey-Bates E, Talukdar M, Li Y, Weiss SR, Sicheri F, Saunthararajah Y, Stark GR, Silverman RH. OAS- RNase L innate immune pathway mediates the cytotoxicity of a DNA-demethylating drug. Proc Natl Acad Sci U S A 2019; 116:5071-6. [PMID: 30814222 DOI: 10.1073/pnas.1815071116] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Drugs that cause epigenetic modification of DNA, such as 5-azacytidine (AZA), are used clinically to treat myelodysplastic syndromes and acute myeloid leukemia. In addition, AZA is being investigated for use against a range of different types of solid tumors, including lung and colorectal cancers. Treatment with AZA causes demethylation of DNA, thus increasing RNA synthesis, including the synthesis of double-stranded RNA, which is otherwise produced in virus-infected cells. We determined that cell death in response to AZA requires the antiviral enzyme RNase L. The results identify a drug target for enhancing the anticancer activity and reducing the toxicity of AZA and related drugs. Drugs that reverse epigenetic silencing, such as the DNA methyltransferase inhibitor (DNMTi) 5-azacytidine (AZA), have profound effects on transcription and tumor cell survival. AZA is an approved drug for myelodysplastic syndromes and acute myeloid leukemia, and is under investigation for different solid malignant tumors. AZA treatment generates self, double-stranded RNA (dsRNA), transcribed from hypomethylated repetitive elements. Self dsRNA accumulation in DNMTi-treated cells leads to type I IFN production and IFN-stimulated gene expression. Here we report that cell death in response to AZA treatment occurs through the 2′,5′-oligoadenylate synthetase (OAS)-RNase L pathway. OASs are IFN-induced enzymes that synthesize the RNase L activator 2-5A in response to dsRNA. Cells deficient in RNase L or OAS1 to 3 are highly resistant to AZA, as are wild-type cells treated with a small-molecule inhibitor of RNase L. A small-molecule inhibitor of c-Jun NH2-terminal kinases (JNKs) also antagonizes RNase L-dependent cell death in response to AZA, consistent with a role for JNK in RNase L-induced apoptosis. In contrast, the rates of AZA-induced and RNase L-dependent cell death were increased by transfection of 2-5A, by deficiencies in ADAR1 (which edits and destabilizes dsRNA), PDE12 or AKAP7 (which degrade 2-5A), or by ionizing radiation (which induces IFN-dependent signaling). Finally, OAS1 expression correlates with AZA sensitivity in the NCI-60 set of tumor cell lines, suggesting that the level of OAS1 can be a biomarker for predicting AZA sensitivity of tumor cells. These studies may eventually lead to pharmacologic strategies for regulating the antitumor activity and toxicity of AZA and related drugs.
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40
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Nogimori T, Furutachi K, Ogami K, Hosoda N, Hoshino SI. A novel method for stabilizing microRNA mimics. Biochem Biophys Res Commun 2019; 511:422-426. [PMID: 30799083 DOI: 10.1016/j.bbrc.2019.02.075] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 02/14/2019] [Indexed: 11/27/2022]
Abstract
MicroRNAs (miRNAs) are a class of small non-coding RNAs that negatively regulate gene expression at post-transcriptional level via translational repression and/or mRNA degradation. miRNAs are associated with many cellular processes, and down-regulation of miRNAs causes numerous diseases including cancer, neurological disorders, inflammation, and cardiovascular diseases, for which miRNA replacement therapy has emerged as a promising approach. This approach aims to restore down-regulated miRNAs using synthetic miRNA mimics. However, it remains a critical issue that miRNA mimics are unstable and transient in cells. Here, we first show that miRNA mimics are rapidly degraded by a mechanism different from Tudor-staphylococcal/micrococcal-like nuclease (TSN)-mediated miRNA decay, which degrades endogenous miRNAs, and newly identified 2'-5'-oligoadenylate synthetase (OAS)/RNase L as key factors responsible for the degradation of miRNA mimics in human cells. Our results suggest that the OAS1 recognizes miRNA mimics and produces 2'-5'-oligoadenylates (2-5A), which leads to the activation of latent endoribonuclease RNase L to degrade miRNA mimics. A small-molecule inhibitor that blocks RNase L can stabilize miRNA mimics. These findings provide a promising method for the stabilization of miRNA mimics, as well as for the efficient miRNA replacement therapy.
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Affiliation(s)
- Takuto Nogimori
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Kazuya Furutachi
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Koichi Ogami
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Nao Hosoda
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Shin-Ichi Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan.
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41
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Wang R, Kang Y, Li H, Ma H, Wang W, Cheng Y, Ji P, Zhang E, Zhao M. Molecular cloning and functional characterization of porcine 2',5'-oligoadenylate synthetase 1b and its effect on infection with porcine reproductive and respiratory syndrome virus. Vet Immunol Immunopathol 2019; 209:22-30. [PMID: 30885302 DOI: 10.1016/j.vetimm.2019.01.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 01/10/2019] [Accepted: 01/21/2019] [Indexed: 01/29/2023]
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) has previously been shown to increase porcine 2'-5'-oligoadenylate synthase (OAS) 1a expression, but the specific role of porcine OAS1b (pOAS1b) in PRRSV replication remains unknown. In this study, we conducted sequence analysis of the porcine OAS1b gene and studied the effects of its overexpression or silencing on PRRSV replication. OAS1b, localized mainly in the cytoplasm, was found to contain conserved protein domains, such as the P-Loop and D-Box, indicating that its nucleotidyl transferase activity was complete and the antiviral effect depended on ribonuclease L (RNase L). OAS1b overexpression inhibited PRRSV replication, whereas small-interfering-RNA silencing of OAS1b resulted in increased virus titers. Additionally, OAS1b promoted expression of interferons as well as interferon-β promoter activity. These results lay the theoretical foundation for the development of new anti-PRRSV strategies.
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Affiliation(s)
- Ruining Wang
- School of Pharmaceutical Engineering, Henan University of Animal Husbandry and Economy, Zhengzhou 450046, People's Republic of China
| | - Yinfeng Kang
- State Key Laboratory of Oncology in South China, Department of Experimental Research, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 467500, People's Republic of China
| | - Huawei Li
- College of Biology Engineering, Henan University of Animal Husbandry and Economy, Zhengzhou 450046, People's Republic of China
| | - Hongfang Ma
- College of Animal Husbandry and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, People's Republic of China
| | - Wenjia Wang
- School of Pharmaceutical Engineering, Henan University of Animal Husbandry and Economy, Zhengzhou 450046, People's Republic of China
| | - Yanfen Cheng
- College of Food Science and Engineering, Shanxi Agricultural University, Taigu 030801, People's Republic of China
| | - Pengchao Ji
- College of Animal Husbandry and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, People's Republic of China
| | - Erqin Zhang
- College of Animal Husbandry and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, People's Republic of China
| | - Mengmeng Zhao
- College of Animal Husbandry and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, People's Republic of China.
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42
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Carey CM, Govande AA, Cooper JM, Hartley MK, Kranzusch PJ, Elde NC. Recurrent Loss-of-Function Mutations Reveal Costs to OAS1 Antiviral Activity in Primates. Cell Host Microbe 2019; 25:336-343.e4. [PMID: 30713099 DOI: 10.1016/j.chom.2019.01.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 10/07/2018] [Accepted: 12/28/2018] [Indexed: 11/16/2022]
Abstract
Immune responses counteract infections but also cause collateral damage to hosts. Oligoadenylate synthetase 1 (OAS1) binds double-stranded RNA from invading viruses and produces 2'-5' linked oligoadenylate (2-5A) to activate ribonuclease L (RNase L), which cleaves RNA to inhibit virus replication. OAS1 can also undergo autoactivation by host RNAs, a potential trade-off to antiviral activity. We investigated functional variation in primate OAS1 as a model for how immune pathways evolve to mitigate costs and observed a surprising frequency of loss-of-function variation. In gorillas, we identified a polymorphism that severely decreases catalytic function, mirroring a common variant in humans that impairs 2-5A synthesis through alternative splicing. OAS1 loss-of-function variation is also common in monkeys, including complete loss of 2-5A synthesis in tamarins. The frequency of loss-of-function alleles suggests that costs associated with OAS1 activation can be so detrimental to host fitness that pathogen-protective effects are repeatedly forfeited.
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Affiliation(s)
- Clayton M Carey
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Apurva A Govande
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Juliane M Cooper
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Melissa K Hartley
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Philip J Kranzusch
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Nels C Elde
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
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43
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Chitrakar A, Rath S, Donovan J, Demarest K, Li Y, Sridhar RR, Weiss SR, Kotenko SV, Wingreen NS, Korennykh A. Real-time 2-5A kinetics suggest that interferons β and λ evade global arrest of translation by RNase L. Proc Natl Acad Sci U S A 2019; 116:2103-11. [PMID: 30655338 DOI: 10.1073/pnas.1818363116] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cells of all mammals recognize double-stranded RNA (dsRNA) as a foreign material. In response, they release interferons (IFNs) and activate a ubiquitously expressed pseudokinase/endoribonuclease RNase L. RNase L executes regulated RNA decay and halts global translation. Here, we developed a biosensor for 2',5'-oligoadenylate (2-5A), the natural activator of RNase L. Using this biosensor, we found that 2-5A was acutely synthesized by cells in response to dsRNA sensing, which immediately triggered cellular RNA cleavage by RNase L and arrested host protein synthesis. However, translation-arrested cells still transcribed IFN-stimulated genes and secreted IFNs of types I and III (IFN-β and IFN-λ). Our data suggest that IFNs escape from the action of RNase L on translation. We propose that the 2-5A/RNase L pathway serves to rapidly and accurately suppress basal protein synthesis, preserving privileged production of defense proteins of the innate immune system.
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44
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Freundt EC, Drappier M, Michiels T. Innate Immune Detection of Cardioviruses and Viral Disruption of Interferon Signaling. Front Microbiol 2018; 9:2448. [PMID: 30369921 PMCID: PMC6194174 DOI: 10.3389/fmicb.2018.02448] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 09/25/2018] [Indexed: 12/24/2022] Open
Abstract
Cardioviruses are members of the Picornaviridae family and infect a variety of mammals, from mice to humans. Replication of cardioviruses produces double stranded RNA that is detected by helicases in the RIG-I-like receptor family and leads to a signaling cascade to produce type I interferon. Like other viruses within Picornaviridae, however, cardioviruses have evolved several mechanisms to inhibit interferon production. In this review, we summarize recent findings that have uncovered several proteins enabling efficient detection of cardiovirus dsRNA and discuss which cell types may be most important for interferon production in vivo. Additionally, we describe how cardiovirus proteins L, 3C and L∗ disrupt interferon production and antagonize the antiviral activity of interferon effector molecules.
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Affiliation(s)
- Eric C Freundt
- Department of Biology, The University of Tampa, Tampa, FL, United States
| | - Melissa Drappier
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Thomas Michiels
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
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45
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Wang R, Ma H, Kang Y, Li C, Li H, Zhang E, Ji P, He J, Zhao M. Molecular Cloning and Identification of the 2'-5' Oligoadenylate Synthetase 2 Gene in Chinese Domestic Pigs Through Bioinformatics Analysis, and Determination of Its Antiviral Activity Against Porcine Reproductive and Respiratory Syndrome Virus Infection. Indian J Microbiol 2018; 58:332-344. [PMID: 30013278 DOI: 10.1007/s12088-018-0731-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/20/2018] [Indexed: 01/09/2023] Open
Abstract
An interferon-mediated antiviral protein, 2'-5' oligoadenylate synthetase 2, plays an important role in the antiviral response of interferons. In this study, 2'-5' oligoadenylate synthetase 2 genes were cloned from Chinese domestic pigs. Bioinformatics analysis revealed that the 2024-bp long open reading fame encodes 707 amino acids. There are two conserved regions in this protein: the nucleotidyltransferase domain, and the 2'-5' oligoadenylate synthetase domain (OAS). Genetic evolution analysis showed that the 2'-5' oligoadenylate synthetase 2 gene in domestic pigs is closely related to that of cattle. There are multiple antigenic sites, no signal peptide, and no transmembrane region in the gene, which is predicted to be a hydrophilic protein. Secondary structures were found to be mainly alpha helix-based; its tertiary structure is close to that of humans and cattle, but not that of mice. Tissue distribution results indicated that this protein is distributed in multiple organs, with high distribution in the liver; it is mainly localized in the cytoplasm. PRRSV infection, interferon-beta, and Poly(I: C) treatment all promoted 2'-5' oligoadenylate synthetase 2 gene expression. Overexpression and RNA silencing of porcine OAS2 inhibited and promoted PRRSV replication in cells, respectively. The inhibitory effect of porcine OAS2 was mainly dependent on RNase L, similar to what was predicted. This study has laid the foundation for future antiviral studies in pig, and provided a new way of preventing and treating PRRSV in the future.
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Affiliation(s)
- Ruining Wang
- 1School of Pharmaceutical Engineering, Henan University of Animal Husbandry and Economy, Zhengzhou, 450046 People's Republic of China
| | - Hongfang Ma
- 2College of Animal Husbandry and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002 People's Republic of China
| | - Yinfeng Kang
- 3State Key Laboratory of Oncology in South China, Department of Experimental Research, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou, 467500 People's Republic of China
| | - Cunfa Li
- 1School of Pharmaceutical Engineering, Henan University of Animal Husbandry and Economy, Zhengzhou, 450046 People's Republic of China
| | - Huawei Li
- 4College of Biology Engineering, Henan University of Animal Husbandry and Economy, Zhengzhou, 450046 People's Republic of China
| | - Erqin Zhang
- 2College of Animal Husbandry and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002 People's Republic of China
| | - Pengchao Ji
- 2College of Animal Husbandry and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002 People's Republic of China
| | - Jian He
- 2College of Animal Husbandry and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002 People's Republic of China
| | - Mengmeng Zhao
- 2College of Animal Husbandry and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002 People's Republic of China
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Donovan J, Rath S, Kolet-Mandrikov D, Korennykh A. Rapid RNase L-driven arrest of protein synthesis in the dsRNA response without degradation of translation machinery. RNA 2017; 23:1660-1671. [PMID: 28808124 PMCID: PMC5648034 DOI: 10.1261/rna.062000.117] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 08/06/2017] [Indexed: 05/20/2023]
Abstract
Mammalian cells respond to double-stranded RNA (dsRNA) by activating a translation-inhibiting endoribonuclease, RNase L. Consensus in the field indicates that RNase L arrests protein synthesis by degrading ribosomal RNAs (rRNAs) and messenger RNAs (mRNAs). However, here we provide evidence for a different and far more efficient mechanism. By sequencing abundant RNA fragments generated by RNase L in human cells, we identify site-specific cleavage of two groups of noncoding RNAs: Y-RNAs, whose function is poorly understood, and cytosolic tRNAs, which are essential for translation. Quantitative analysis of human RNA cleavage versus nascent protein synthesis in lung carcinoma cells shows that RNase L stops global translation when tRNAs, as well as rRNAs and mRNAs, are still intact. Therefore, RNase L does not have to degrade the translation machinery to stop protein synthesis. Our data point to a rapid mechanism that transforms a subtle RNA cleavage into a cell-wide translation arrest.
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Affiliation(s)
- Jesse Donovan
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - Sneha Rath
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - David Kolet-Mandrikov
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - Alexei Korennykh
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
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Pillon MC, Stanley RE. Nuclease integrated kinase super assemblies (NiKs) and their role in RNA processing. Curr Genet 2017; 64:183-190. [PMID: 28929238 DOI: 10.1007/s00294-017-0749-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 01/24/2023]
Abstract
Here we highlight the Grc3/Las1 complex, an essential RNA processing machine that is well conserved across eukaryotes and required for processing the pre-ribosomal RNA (pre-rRNA). Las1 is an endoribonuclease that cleaves the pre-rRNA while Grc3 is a polynucleotide kinase that phosphorylates the Las1-cleaved RNA product. Recently we showed that Grc3 and Las1 assemble into a higher-order complex composed of a dimer of Grc3/Las1 heterodimers that is required for nuclease and kinase activity. Unexpectedly, we found that the Grc3/Las1 complex draws numerous parallels with two other eukaryotic nucleases, Ire1 and RNase L. In this perspective we explore the similarities and differences between this family of nuclease integrated kinase super assemblies (NiKs) and their distinct roles in RNA cleavage.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA.
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Zhao M, Wan B, Li H, He J, Chen X, Wang L, Wang Y, Xie S, Qiao S, Zhang G. Porcine 2', 5'-oligoadenylate synthetase 2 inhibits porcine reproductive and respiratory syndrome virus replication in vitro. Microb Pathog 2017; 111:14-21. [PMID: 28804020 DOI: 10.1016/j.micpath.2017.08.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 12/21/2022]
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is acknowledged a fulminating infectious pathogen affecting the pig farming industry, and current vaccines and drugs could hardly inhibit this virus. The 2', 5'-oligoadenylate synthetase (OASs) have antiviral activities, but the role(s) played by porcine OAS2 in protection against PRRSV infection are unknown. Here we found that endogenous expression of the porcine OAS2 gene could be promoted by interferon (IFN)-beta or PRRSV infection in porcine alveolar macrophages. Knockdown of porcine OAS2 led to increases in PRRSV replication, and OAS2 expression suppressed replication of PRRSV in a retinoic acid inducible gene I (RIG-I)-dependent manner, anti-PRRSV activity of porcine OAS2 would be lost if RNase L and OAS2 were both silenced. This discovery illustrates a pathway that porcine OAS2 responses to host anti-PRRSV function.
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Affiliation(s)
- Mengmeng Zhao
- College of Animal Husbandry and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, People's Republic of China
| | - Bo Wan
- College of Animal Husbandry and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, People's Republic of China
| | - Huawei Li
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, People's Republic of China
| | - Jian He
- College of Animal Husbandry and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, People's Republic of China
| | - Xinxin Chen
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, People's Republic of China
| | - Linjian Wang
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, People's Republic of China
| | - Yinbiao Wang
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, People's Republic of China
| | - Sha Xie
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, People's Republic of China
| | - Songlin Qiao
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, People's Republic of China.
| | - Gaiping Zhang
- College of Animal Husbandry and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, People's Republic of China; Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, People's Republic of China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China.
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Drappier M, Opperdoes FR, Michiels T. Nonstructural Protein L* Species Specificity Supports a Mouse Origin for Vilyuisk Human Encephalitis Virus. J Virol 2017; 91:e00573-17. [PMID: 28446680 DOI: 10.1128/JVI.00573-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 04/21/2017] [Indexed: 11/20/2022] Open
Abstract
Vilyuisk human encephalitis virus (VHEV) is a picornavirus related to Theiler's murine encephalomyelitis virus (TMEV). VHEV was isolated from human material passaged in mice. Whether this VHEV is of human or mouse origin is therefore unclear. We took advantage of the species-specific activity of the nonstructural L* protein of theiloviruses to track the origin of TMEV isolates. TMEV L* inhibits RNase L, the effector enzyme of the interferon pathway. By using coimmunoprecipitation and functional RNase L assays, the species specificity of RNase L antagonism was tested for L* from mouse (DA) and rat (RTV-1) TMEV strains as well as for VHEV. Coimmunoprecipitation and functional assay data confirmed the species specificity of L* activity and showed that L* from rat strain RTV-1 inhibited rat but not mouse or human RNase L. Next, we showed that the VHEV L* protein was phylogenetically related to L* of mouse viruses and that it failed to inhibit human RNase L but readily antagonized mouse RNase L, unambiguously showing the mouse origin of VHEV.IMPORTANCE Defining the natural host of a virus can be a thorny issue, especially when the virus was isolated only once or when the isolation story is complex. The species Theilovirus includes Theiler's murine encephalomyelitis virus (TMEV), infecting mice and rats, and Saffold virus (SAFV), infecting humans. One TMEV strain, Vilyuisk human encephalitis virus (VHEV), however, was isolated from mice that were inoculated with cerebrospinal fluid of a patient presenting with chronic encephalitis. It is therefore unclear whether VHEV was derived from the human sample or from the inoculated mouse. The L* protein encoded by TMEV inhibits RNase L, a cellular enzyme involved in innate immunity, in a species-specific manner. Using binding and functional assays, we show that this species specificity even allows discrimination between TMEV strains of mouse and of rat origins. The VHEV L* protein clearly inhibited mouse but not human RNase L, indicating that this virus originates from mice.
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Dayal S, Zhou J, Manivannan P, Siddiqui MA, Ahmad OF, Clark M, Awadia S, Garcia-Mata R, Shemshedini L, Malathi K. RNase L Suppresses Androgen Receptor Signaling, Cell Migration and Matrix Metalloproteinase Activity in Prostate Cancer Cells. Int J Mol Sci 2017; 18:ijms18030529. [PMID: 28257035 PMCID: PMC5372545 DOI: 10.3390/ijms18030529] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 02/15/2017] [Accepted: 02/20/2017] [Indexed: 01/20/2023] Open
Abstract
The interferon antiviral pathways and prostate cancer genetics converge on a regulated endoribonuclease, RNase L. Positional cloning and linkage studies mapped Hereditary Prostate Cancer 1 (HPC1) to RNASEL. To date, there is no correlation of viral infections with prostate cancer, suggesting that RNase L may play additional roles in tumor suppression. Here, we demonstrate a role of RNase L as a suppressor of androgen receptor (AR) signaling, cell migration and matrix metalloproteinase activity. Using RNase L mutants, we show that its nucleolytic activity is dispensable for both AR signaling and migration. The most prevalent HPC1-associated mutations in RNase L, R462Q and E265X, enhance AR signaling and cell migration. RNase L negatively regulates cell migration and attachment on various extracellular matrices. We demonstrate that RNase L knockdown cells promote increased cell surface expression of integrin β1 which activates Focal Adhesion Kinase-Sarcoma (FAK-Src) pathway and Ras-related C3 botulinum toxin substrate 1-guanosine triphosphatase (Rac1-GTPase) activity to increase cell migration. Activity of matrix metalloproteinase (MMP)-2 and -9 is significantly increased in cells where RNase L levels are ablated. We show that mutations in RNase L found in HPC patients may promote prostate cancer by increasing expression of AR-responsive genes and cell motility and identify novel roles of RNase L as a prostate cancer susceptibility gene.
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Affiliation(s)
- Shubham Dayal
- Department of Biological Sciences, 2801 W. Bancroft St., University of Toledo, Toledo, OH 43606, USA.
| | - Jun Zhou
- Department of Biological Sciences, 2801 W. Bancroft St., University of Toledo, Toledo, OH 43606, USA.
| | - Praveen Manivannan
- Department of Biological Sciences, 2801 W. Bancroft St., University of Toledo, Toledo, OH 43606, USA.
| | - Mohammad Adnan Siddiqui
- Department of Biological Sciences, 2801 W. Bancroft St., University of Toledo, Toledo, OH 43606, USA.
| | - Omaima Farid Ahmad
- Department of Biological Sciences, 2801 W. Bancroft St., University of Toledo, Toledo, OH 43606, USA.
| | - Matthew Clark
- Department of Biological Sciences, 2801 W. Bancroft St., University of Toledo, Toledo, OH 43606, USA.
| | - Sahezeel Awadia
- Department of Biological Sciences, 2801 W. Bancroft St., University of Toledo, Toledo, OH 43606, USA.
| | - Rafael Garcia-Mata
- Department of Biological Sciences, 2801 W. Bancroft St., University of Toledo, Toledo, OH 43606, USA.
| | - Lirim Shemshedini
- Department of Biological Sciences, 2801 W. Bancroft St., University of Toledo, Toledo, OH 43606, USA.
| | - Krishnamurthy Malathi
- Department of Biological Sciences, 2801 W. Bancroft St., University of Toledo, Toledo, OH 43606, USA.
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