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Nowicka H, Sekrecka A, Blaszczyk K, Kluzek K, Chang CY, Wesoly J, Lee CK, Bluyssen HAR. ISGF3 and STAT2/IRF9 Control Basal and IFN-Induced Transcription through Genome-Wide Binding of Phosphorylated and Unphosphorylated Complexes to Common ISRE-Containing ISGs. Int J Mol Sci 2023; 24:17635. [PMID: 38139463 PMCID: PMC10743977 DOI: 10.3390/ijms242417635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/14/2023] [Accepted: 12/17/2023] [Indexed: 12/24/2023] Open
Abstract
In addition to the canonical ISGF3 and non-canonical STAT2/IRF9 complexes, evidence is emerging of the role of their unphosphorylated counterparts in IFN-dependent and -independent ISG transcription. To better understand the relation between ISGF3 and U-ISGF3 and STAT2/IRF9 and U-STAT2/IRF9 in IFN-I-stimulated transcriptional responses, we performed RNA-Seq and ChIP-Seq, in combination with phosphorylation inhibition and antiviral experiments. First, we identified a group of ISRE-containing ISGs that were commonly regulated in IFNα-treated WT and STAT1-KO cells. Thus, in 2fTGH and Huh7.5 WT cells, early and long-term IFNα-inducible transcription and antiviral activity relied on the DNA recruitment of the ISGF3 components STAT1, STAT2 and IRF9 in a phosphorylation- and time-dependent manner. Likewise, in ST2-U3C and Huh-STAT1KO cells lacking STAT1, delayed IFN responses correlated with DNA binding of phosphorylated STAT2/IRF9 but not U-STAT2/IRF9. In addition, comparative experiments in U3C (STAT1-KO) cells overexpressing all the ISGF3 components (ST1-ST2-IRF9-U3C) revealed U-ISGF3 (and possibly U-STAT2/IRF9) chromatin interactions to correlate with phosphorylation-independent ISG transcription and antiviral activity. Together, our data point to the dominant role of the canonical ISGF3 and non-canonical STAT2/IRF9, without a shift to U-ISGF3 or U-STAT2/IRF9, in the regulation of early and prolonged ISG expression and viral protection. At the same time, they suggest the threshold-dependent role of U-ISFG3, and potentially U-STAT2/IRF9, in the regulation of constitutive and possibly long-term IFNα-dependent responses.
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Affiliation(s)
- Hanna Nowicka
- Human Molecular Genetics Research Unit, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, 61-614 Poznan, Poland
| | - Agata Sekrecka
- Human Molecular Genetics Research Unit, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, 61-614 Poznan, Poland
| | - Katarzyna Blaszczyk
- Human Molecular Genetics Research Unit, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, 61-614 Poznan, Poland
| | - Katarzyna Kluzek
- Human Molecular Genetics Research Unit, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, 61-614 Poznan, Poland
| | - Chan-Yu Chang
- Graduate Institute of Immunology, National Taiwan University College of Medicine, Taipei 100, Taiwan
| | - Joanna Wesoly
- Laboratory of High Throughput Technologies, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznan, Poland
| | - Chien-Kuo Lee
- Graduate Institute of Immunology, National Taiwan University College of Medicine, Taipei 100, Taiwan
| | - Hans A. R. Bluyssen
- Human Molecular Genetics Research Unit, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, 61-614 Poznan, Poland
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Expression of Concern: SH2 Modified STAT1 Induces HLA-I Expression and Improves IFN-γ Signaling in IFN-α Resistant HCV Replicon Cells. PLoS One 2022; 17:e0266497. [PMID: 35358284 PMCID: PMC8970497 DOI: 10.1371/journal.pone.0266497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Ashley CL, Abendroth A, McSharry BP, Slobedman B. Interferon-Independent Innate Responses to Cytomegalovirus. Front Immunol 2019; 10:2751. [PMID: 31921100 PMCID: PMC6917592 DOI: 10.3389/fimmu.2019.02751] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 11/11/2019] [Indexed: 12/28/2022] Open
Abstract
The critical role of interferons (IFNs) in mediating the innate immune response to cytomegalovirus (CMV) infection is well established. However, in recent years the functional importance of the IFN-independent antiviral response has become clearer. IFN-independent, IFN regulatory factor 3 (IRF3)-dependent interferon-stimulated gene (ISG) regulation in the context of CMV infection was first documented 20 years ago. Since then several IFN-independent, IRF3-dependent ISGs have been characterized and found to be among the most influential in the innate response to CMV. These include virus inhibitory protein, endoplasmic reticulum-associated IFN-inducible (viperin), ISG15, members of the interferon inducible protein with tetratricopeptide repeats (IFIT) family, interferon-inducible transmembrane (IFITM) proteins and myxovirus resistance proteins A and B (MxA, MxB). IRF3-independent, IFN-independent activation of canonically IFN-dependent signaling pathways has also been documented, such as IFN-independent biphasic activation of signal transducer and activator of transcription 1 (STAT1) during infection of monocytes, differential roles of mitochondrial and peroxisomal mitochondrial antiviral-signaling protein (MAVS), and the ability of human CMV (HCMV) immediate early protein 1 (IE1) protein to reroute IL-6 signaling and activation of STAT1 and its associated ISGs. This review examines the role of identified IFN-independent ISGs in the antiviral response to CMV and describes pathways of IFN-independent innate immune response induction by CMV.
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Affiliation(s)
- Caroline L Ashley
- Discipline of Infectious Diseases and Immunology, Faculty of Medicine and Health, Charles Perkins Centre, University of Sydney, Camperdown, NSW, Australia
| | - Allison Abendroth
- Discipline of Infectious Diseases and Immunology, Faculty of Medicine and Health, Charles Perkins Centre, University of Sydney, Camperdown, NSW, Australia
| | - Brian P McSharry
- Discipline of Infectious Diseases and Immunology, Faculty of Medicine and Health, Charles Perkins Centre, University of Sydney, Camperdown, NSW, Australia.,School of Microbiology, University College Cork, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Barry Slobedman
- Discipline of Infectious Diseases and Immunology, Faculty of Medicine and Health, Charles Perkins Centre, University of Sydney, Camperdown, NSW, Australia
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Antonczyk A, Krist B, Sajek M, Michalska A, Piaszyk-Borychowska A, Plens-Galaska M, Wesoly J, Bluyssen HAR. Direct Inhibition of IRF-Dependent Transcriptional Regulatory Mechanisms Associated With Disease. Front Immunol 2019; 10:1176. [PMID: 31178872 PMCID: PMC6543449 DOI: 10.3389/fimmu.2019.01176] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 05/09/2019] [Indexed: 12/24/2022] Open
Abstract
Interferon regulatory factors (IRFs) are a family of homologous proteins that regulate the transcription of interferons (IFNs) and IFN-induced gene expression. As such they are important modulating proteins in the Toll-like receptor (TLR) and IFN signaling pathways, which are vital elements of the innate immune system. IRFs have a multi-domain structure, with the N-terminal part acting as a DNA binding domain (DBD) that recognizes a DNA-binding motif similar to the IFN-stimulated response element (ISRE). The C-terminal part contains the IRF-association domain (IAD), with which they can self-associate, bind to IRF family members or interact with other transcription factors. This complex formation is crucial for DNA binding and the commencing of target-gene expression. IRFs bind DNA and exert their activating potential as homo or heterodimers with other IRFs. Moreover, they can form complexes (e.g., with Signal transducers and activators of transcription, STATs) and collaborate with other co-acting transcription factors such as Nuclear factor-κB (NF-κB) and PU.1. In time, more of these IRF co-activating mechanisms have been discovered, which may play a key role in the pathogenesis of many diseases, such as acute and chronic inflammation, autoimmune diseases, and cancer. Detailed knowledge of IRFs structure and activating mechanisms predisposes IRFs as potential targets for inhibition in therapeutic strategies connected to numerous immune system-originated diseases. Until now only indirect IRF modulation has been studied in terms of antiviral response regulation and cancer treatment, using mainly antisense oligonucleotides and siRNA knockdown strategies. However, none of these approaches so far entered clinical trials. Moreover, no direct IRF-inhibitory strategies have been reported. In this review, we summarize current knowledge of the different IRF-mediated transcriptional regulatory mechanisms and how they reflect the diverse functions of IRFs in homeostasis and in TLR and IFN signaling. Moreover, we present IRFs as promising inhibitory targets and propose a novel direct IRF-modulating strategy employing a pipeline approach that combines comparative in silico docking to the IRF-DBD with in vitro validation of IRF inhibition. We hypothesize that our methodology will enable the efficient identification of IRF-specific and pan-IRF inhibitors that can be used for the treatment of IRF-dependent disorders and malignancies.
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Affiliation(s)
- Aleksandra Antonczyk
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
| | - Bart Krist
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
| | - Malgorzata Sajek
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
| | - Agata Michalska
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
| | - Anna Piaszyk-Borychowska
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
| | - Martyna Plens-Galaska
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
| | - Joanna Wesoly
- Laboratory of High Throughput Technologies, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
| | - Hans A R Bluyssen
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
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Michalska A, Blaszczyk K, Wesoly J, Bluyssen HAR. A Positive Feedback Amplifier Circuit That Regulates Interferon (IFN)-Stimulated Gene Expression and Controls Type I and Type II IFN Responses. Front Immunol 2018; 9:1135. [PMID: 29892288 PMCID: PMC5985295 DOI: 10.3389/fimmu.2018.01135] [Citation(s) in RCA: 198] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 05/07/2018] [Indexed: 12/14/2022] Open
Abstract
Interferon (IFN)-I and IFN-II both induce IFN-stimulated gene (ISG) expression through Janus kinase (JAK)-dependent phosphorylation of signal transducer and activator of transcription (STAT) 1 and STAT2. STAT1 homodimers, known as γ-activated factor (GAF), activate transcription in response to all types of IFNs by direct binding to IFN-II activation site (γ-activated sequence)-containing genes. Association of interferon regulatory factor (IRF) 9 with STAT1–STAT2 heterodimers [known as interferon-stimulated gene factor 3 (ISGF3)] or with STAT2 homodimers (STAT2/IRF9) in response to IFN-I, redirects these complexes to a distinct group of target genes harboring the interferon-stimulated response element (ISRE). Similarly, IRF1 regulates expression of ISGs in response to IFN-I and IFN-II by directly binding the ISRE or IRF-responsive element. In addition, evidence is accumulating for an IFN-independent and -dependent role of unphosphorylated STAT1 and STAT2, with or without IRF9, and IRF1 in basal as well as long-term ISG expression. This review provides insight into the existence of an intracellular amplifier circuit regulating ISG expression and controlling long-term cellular responsiveness to IFN-I and IFN-II. The exact timely steps that take place during IFN-activated feedback regulation and the control of ISG transcription and long-term cellular responsiveness to IFN-I and IFN-II is currently not clear. Based on existing literature and our novel data, we predict the existence of a multifaceted intracellular amplifier circuit that depends on unphosphorylated and phosphorylated ISGF3 and GAF complexes and IRF1. In a combinatorial and timely fashion, these complexes mediate prolonged ISG expression and control cellular responsiveness to IFN-I and IFN-II. This proposed intracellular amplifier circuit also provides a molecular explanation for the existing overlap between IFN-I and IFN-II activated ISG expression.
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Affiliation(s)
- Agata Michalska
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Katarzyna Blaszczyk
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Joanna Wesoly
- Laboratory of High Throughput Technologies, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Hans A R Bluyssen
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
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Huang CJ, Chou CM, Lien HW, Chu CY, Ho JY, Wu Y, Cheng CH. IRF9-Stat2 Fusion Protein as an Innate Immune Inducer to Activate Mx and Interferon-Stimulated Gene Expression in Zebrafish Larvae. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2017; 19:310-319. [PMID: 28500614 DOI: 10.1007/s10126-017-9752-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 04/24/2017] [Indexed: 06/07/2023]
Abstract
Virus infection often causes large amounts of mortality during teleost larvae stage. Strong induction of innate immunity to increase survival rates of teleost larvae has been less reported. In this study, we present a zebrafish IRF9-Stat2 fusion protein (zIRF9-S2C) as a strong innate immunity inducer and characterized induction of interferon-stimulated genes (ISGs) in zebrafish larvae. zIRF9-S2C could mimic IFN-stimulated gene factor 3 (ISGF3) complex to constitutively activate transcription of Mx promoter through IFN-stimulatory element (ISRE) sites. Mutation of two ISRE sites on Mx promoter reduced transactivation activities of Mx promoter induced by zIRF9-S2C. An electrophoretic mobility shift assay experiment shows that zIRF9-S2C could directly bind to two ISRE sites of Mx promoter. Induction of transactivation of Mx promoter by zIRF9-S2C shows significantly higher activity than by zebrafish IFN1 (zIFN1), IFNγ (zIFNγ), and Tetraodon IRF9-S2C (TnIRF9-S2C). zIRF9-S2C raises transcription of Mxa, Mxb, Mxc, Ifnφ1, Ifnφ2, and Ifnφ3 in zebrafish liver ((ZFL) cell line) cells and zebrafish larvae. Collectively, we suggest that IRF9-S2C could activate transcription of ISGs with species-specific recognition and could be an innate immunity inducer in teleost larvae.
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Affiliation(s)
- Chang-Jen Huang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chih-Ming Chou
- Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, 250, Wuxing St, Taipei 110, Taiwan
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Huang-Wei Lien
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Cheng-Ying Chu
- Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan
| | - Jhih-Yun Ho
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yimin Wu
- Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, 250, Wuxing St, Taipei 110, Taiwan
| | - Chia-Hsiung Cheng
- Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, 250, Wuxing St, Taipei 110, Taiwan.
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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STAT1 is essential for the inhibition of hepatitis C virus replication by interferon-λ but not by interferon-α. Sci Rep 2016; 6:38336. [PMID: 27929099 PMCID: PMC5144079 DOI: 10.1038/srep38336] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 11/08/2016] [Indexed: 12/21/2022] Open
Abstract
Interferon-α (IFN-α) and IFN-λ are structurally distinct cytokines that bind to different receptors, but induce expression of similar sets of genes through Janus kinase (JAK)-signal transducers and activators of transcription (STAT) pathways. The difference between IFN-α and IFN-λ signaling remains poorly understood. Here, using the CRISPR/Cas9 system, we examine the role of STAT1 and STAT2 in the inhibition of hepatitis C virus (HCV) replication by IFN-α and IFN-λ. Treatment with IFN-α increases expression of IFN-stimulated genes (ISGs) such as double-stranded RNA-activated protein kinase (PKR) and decreases viral RNA and protein levels in HCV-infected Huh-7.5 human hepatoma cells. These responses are only partially attenuated by knockout of STAT1 but are abolished by knockout of STAT2. In contrast, the inhibition of HCV replication by IFN-λ is abolished by knockout of STAT1 or STAT2. Microarray analysis reveals that IFN-α but not IFN-λ can induce expression of the majority of ISGs in STAT1 knockout cells. These findings suggest that IFN-α can inhibit HCV replication through a STAT2-dependent but STAT1-independent pathway, whereas IFN-λ induces ISG expression and inhibits HCV replication exclusively through a STAT1- and STAT2-dependent pathway.
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Hepatitis C Virus Infection Induces Autophagy as a Prosurvival Mechanism to Alleviate Hepatic ER-Stress Response. Viruses 2016; 8:v8050150. [PMID: 27223299 PMCID: PMC4885105 DOI: 10.3390/v8050150] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/04/2016] [Accepted: 05/18/2016] [Indexed: 12/17/2022] Open
Abstract
Hepatitis C virus (HCV) infection frequently leads to chronic liver disease, liver cirrhosis and hepatocellular carcinoma (HCC). The molecular mechanisms by which HCV infection leads to chronic liver disease and HCC are not well understood. The infection cycle of HCV is initiated by the attachment and entry of virus particles into a hepatocyte. Replication of the HCV genome inside hepatocytes leads to accumulation of large amounts of viral proteins and RNA replication intermediates in the endoplasmic reticulum (ER), resulting in production of thousands of new virus particles. HCV-infected hepatocytes mount a substantial stress response. How the infected hepatocyte integrates the viral-induced stress response with chronic infection is unknown. The unfolded protein response (UPR), an ER-associated cellular transcriptional response, is activated in HCV infected hepatocytes. Over the past several years, research performed by a number of laboratories, including ours, has shown that HCV induced UPR robustly activates autophagy to sustain viral replication in the infected hepatocyte. Induction of the cellular autophagy response is required to improve survival of infected cells by inhibition of cellular apoptosis. The autophagy response also inhibits the cellular innate antiviral program that usually inhibits HCV replication. In this review, we discuss the physiological implications of the HCV-induced chronic ER-stress response in the liver disease progression.
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Ferraris P, Chandra PK, Panigrahi R, Aboulnasr F, Chava S, Kurt R, Pawlotsky JM, Wilkens L, Osterlund P, Hartmann R, Balart LA, Wu T, Dash S. Cellular Mechanism for Impaired Hepatitis C Virus Clearance by Interferon Associated with IFNL3 Gene Polymorphisms Relates to Intrahepatic Interferon-λ Expression. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:938-51. [PMID: 26896692 PMCID: PMC5807932 DOI: 10.1016/j.ajpath.2015.11.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/13/2015] [Accepted: 11/24/2015] [Indexed: 12/12/2022]
Abstract
The single nucleotide polymorphism located within the IFNL3 (also known as IL28B) promoter is one of the host factors associated with hepatitis C virus (HCV) clearance by interferon (IFN)-α therapy; however the mechanism remains unknown. We investigated how IL28B gene polymorphism influences HCV clearance with infected primary human hepatocytes, liver biopsies, and hepatoma cell lines. Our study confirms that the rs12979860-T/T genotype has a strong correlation with ss469415590-ΔG/ΔG single nucleotide polymorphism that produces IFN-λ4 protein. We found that IFN-α and IFN-λ1 antiviral activity against HCV was impaired in IL28B T/T infected hepatocytes compared with C/C genotype. Western blot analysis showed that IL28B TT genotype hepatocytes expressed higher levels of IFN-λ proteins (IL28B, IL-29), preactivated IFN-stimulated gene (ISG) expression, and impaired Stat phosphorylation when stimulated with either IFN-α or IFN-λ1. Furthermore, we showed that silencing IFN-λ1 in T/T cell line reduced basal ISG expression and improved antiviral activity. Likewise, overexpression of IFN-λ (1 to 4) in C/C cells induced basal ISG expression and prevented IFN-α antiviral activity. We showed that IFN-λ4, produced at low level only in T/T cells induced expression of IL28B and IL-29 and prevented IFN-α antiviral activity in HCV cell culture. Our results suggest that IFN-λ4 protein expression associated with the IL28B-T/T variant preactivates the Janus kinase-Stat signaling, leading to impaired HCV clearance by both IFN-α and IFN-λ.
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Affiliation(s)
- Pauline Ferraris
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana
| | - Partha K Chandra
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana
| | - Rajesh Panigrahi
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana
| | - Fatma Aboulnasr
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana
| | - Srinivas Chava
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana
| | - Ramazan Kurt
- Department of Medicine, Gastroenterology, and Hepatology, Tulane University Health Sciences Center, New Orleans, Louisiana
| | - Jean-Michel Pawlotsky
- Department of Molecular Virology and Immunology, Institut Mondor de la Recherche, Creteil, France
| | - Ludwig Wilkens
- Institute of Pathology, University of Bern, Bern, Switzerland
| | - Pamela Osterlund
- Department of Vaccination and Immune Protection Viral Infections, National Institute for Health and Welfare, Helsinki, Finland
| | - Rune Hartmann
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Luis A Balart
- Department of Medicine, Gastroenterology, and Hepatology, Tulane University Health Sciences Center, New Orleans, Louisiana
| | - Tong Wu
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana
| | - Srikanta Dash
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana; Department of Medicine, Gastroenterology, and Hepatology, Tulane University Health Sciences Center, New Orleans, Louisiana.
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The unique role of STAT2 in constitutive and IFN-induced transcription and antiviral responses. Cytokine Growth Factor Rev 2016; 29:71-81. [PMID: 27053489 DOI: 10.1016/j.cytogfr.2016.02.010] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 02/27/2016] [Indexed: 11/20/2022]
Abstract
In the canonical pathway of IFN-I-mediated signaling, phosphorylation of STAT1 and STAT2 leads to heterodimerization and interaction with IRF9. This complex, also known as IFN-stimulated gene factor 3 (ISGF3), then translocates into the nucleus and binds the IFN-I-stimulated response element (ISRE) leading to the activation of transcription of over 300 interferon stimulated genes (ISGs). In addition, STAT1 homodimers [known as γ-activated factor (GAF)] are formed and translocate to the nucleus, where they target genes containing the γ-activated sequence (GAS). The primary function of ISGF3 is to mediate a rapid and robust IFN-I activated response by regulating transient transcription of antiviral ISGs. This requires the quick assembly of ISGF3 from its pre-existing components STAT1, STAT2 and IRF9 and transport to the nucleus to bind ISRE-containing ISGs. The exact events that take place in formation, nuclear translocation and DNA-binding of active ISGF3 are still not clear. Over the years many studies have provided evidence for the existence of a multitude of alternative STAT2-containing (ISRE or GAS-binding) complexes involved in IFN-I signaling, emphasizing the importance of STAT2 in the regulation of specific IFN-I-induced transcriptional programs, independent of its involvement in the classical ISGF3 complex. This review describes the unique role of STAT2 in differential complex formation of unphosphorylated and phosphorylated ISGF3 components that direct constitutive and IFN-I-stimulated transcriptional responses. In addition, we highlight the existence of a STAT1-independent IFN-I signaling pathway, where STAT2/IRF9 can potentially substitute for the role of ISGF3 and offer a back-up response against viral infection.
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STAT2/IRF9 directs a prolonged ISGF3-like transcriptional response and antiviral activity in the absence of STAT1. Biochem J 2015; 466:511-24. [PMID: 25564224 PMCID: PMC4403947 DOI: 10.1042/bj20140644] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Evidence is accumulating for the existence of a signal transducer and activator of transcription 2 (STAT2)/interferon regulatory factor 9 (IRF9)-dependent, STAT1-independent interferon alpha (IFNα) signalling pathway. However, no detailed insight exists into the genome-wide transcriptional regulation and the biological implications of STAT2/IRF9-dependent IFNα signalling as compared with interferon-stimulated gene factor 3 (ISGF3). In STAT1-defeicient U3C cells stably overexpressing human STAT2 (hST2-U3C) and STAT1-deficient murine embryonic fibroblast cells stably overexpressing mouse STAT2 (mST2-MS1KO) we observed that the IFNα-induced expression of 2'-5'-oligoadenylate synthase 2 (OAS2) and interferon-induced protein with tetratricopeptide repeats 1 (Ifit1) correlated with the kinetics of STAT2 phosphorylation, and the presence of a STAT2/IRF9 complex requiring STAT2 phosphorylation and the STAT2 transactivation domain. Subsequent microarray analysis of IFNα-treated wild-type (WT) and STAT1 KO cells overexpressing STAT2 extended our observations and identified ∼120 known antiviral ISRE-containing interferon-stimulated genes (ISGs) commonly up-regulated by STAT2/IRF9 and ISGF3. The STAT2/IRF9-directed expression profile of these IFN-stimulated genes (ISGs) was prolonged as compared with the early and transient response mediated by ISGF3. In addition, we identified a group of 'STAT2/IRF9-specific' ISGs, whose response to IFNα was ISGF3-independent. Finally, STAT2/IRF9 was able to trigger an antiviral response upon encephalomyocarditis virus (EMCV) and vesicular stomatitis Indiana virus (VSV). Our results further prove that IFNα-activated STAT2/IRF9 induces a prolonged ISGF3-like transcriptome and generates an antiviral response in the absence of STAT1. Moreover, the existence of 'STAT2/IRF9-specific' target genes predicts a novel role of STAT2 in IFNα signalling.
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Cheng CH, Chou CM, Chu CY, Chen GD, Lien HW, Hwang PP, Chang MS, Huang CJ. Differential regulation of Tetraodon nigroviridis Mx gene promoter activity by constitutively-active forms of STAT1, STAT2, and IRF9. FISH & SHELLFISH IMMUNOLOGY 2014; 38:230-243. [PMID: 24680831 DOI: 10.1016/j.fsi.2014.03.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 03/03/2014] [Accepted: 03/12/2014] [Indexed: 06/03/2023]
Abstract
Induction of interferons (IFNs) produces an innate immune response through activation of the JAK-STAT signaling pathway. Type I IFN signaling activates downstream gene expression through the IFN-stimulated gene factor 3 (ISGF3) complex, while type II IFN (IFN-γ) signaling is mediated through active STAT1 protein. The IFN target gene Mx is involved in the defense against viral infection. However, the mechanism by which Tetraodon (pufferfish) Mx is regulated by IFN signaling has not been identified. In this study, we describe the cloning and expression of Tetraodon STAT1, STAT2, and IFN regulatory factor 9 (IRF9). By combining constitutively-active STAT1 (STAT1-JH1) and STAT2 (STA2-JH1) fusion proteins with IRF9, we demonstrate that a constitutively-active ISGF3 complex increases the transcriptional activity of the Tetraodon Mx promoter via direct binding to two IFN-stimulated response element (ISRE) sites. In addition, a constitutively-active TnIRF9-S2C containing a fusion of the C-terminal region of STAT2 and IRF9 also activated the Mx promoter through binding to the ISRE sites. Furthermore, constitutively-active STAT1-JH1 elevates Mx promoter activity through two IFN gamma-activated sequence (GAS) elements. The Mx promoter is also activated by constitutively-active TnIRF9-S2C and STAT1-JH1 protein, as determined using an in vivo luciferase assay. We conclude that the Tetraodon Mx gene is activated via Type I (IFN-1) and Type II (IFN-γ) signaling. These results provide mechanistic insights into the role of IFN signaling in teleosts, and the in vivo luciferase assay may be suitable as a tool for studying induction and regulation by IFNs in teleost fish.
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Affiliation(s)
- Chia-Hsiung Cheng
- Department of Biochemistry, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
| | - Chih-Ming Chou
- Department of Biochemistry, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - Cheng-Ying Chu
- The Center of Translational Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - Gen-Der Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Huang-Wei Lien
- Institute of Fisheries Sciences, National Taiwan University, Taipei 106, Taiwan
| | - Pung-Pung Hwang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
| | - Mau-Sun Chang
- Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan
| | - Chang-Jen Huang
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan.
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13
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Chandra PK, Bao L, Song K, Aboulnasr FM, Baker DP, Shores N, Wimley WC, Liu S, Hagedorn CH, Fuchs SY, Wu T, Balart LA, Dash S. HCV infection selectively impairs type I but not type III IFN signaling. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 184:214-29. [PMID: 24215913 DOI: 10.1016/j.ajpath.2013.10.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 09/26/2013] [Accepted: 10/01/2013] [Indexed: 02/07/2023]
Abstract
A stable and persistent Hepatitis C virus (HCV) replication cell culture model was developed to examine clearance of viral replication during long-term treatment using interferon-α (IFN-α), IFN-λ, and ribavirin (RBV). Persistently HCV-infected cell culture exhibited an impaired antiviral response to IFN-α+RBV combination treatment, whereas IFN-λ treatment produced a strong and sustained antiviral response that cleared HCV replication. HCV replication in persistently infected cells induced chronic endoplasmic reticulum (ER) stress and an autophagy response that selectively down-regulated the functional IFN-α receptor-1 chain of type I, but not type II (IFN-γ) or type III (IFN-λ) IFN receptors. Down-regulation of IFN-α receptor-1 resulted in defective JAK-STAT signaling, impaired STAT phosphorylation, and impaired nuclear translocation of STAT. Furthermore, HCV replication impaired RBV uptake, because of reduced expression of the nucleoside transporters ENT1 and CNT1. Silencing ER stress and the autophagy response using chemical inhibitors or siRNA additively inhibited HCV replication and induced viral clearance by the IFN-α+RBV combination treatment. These results indicate that HCV induces ER stress and that the autophagy response selectively impairs type I (but not type III) IFN signaling, which explains why IFN-λ (but not IFN-α) produced a sustained antiviral response against HCV. The results also indicate that inhibition of ER stress and of the autophagy response overcomes IFN-α+RBV resistance mechanisms associated with HCV infection.
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Affiliation(s)
- Partha K Chandra
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana
| | - Lili Bao
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana
| | - Kyoungsub Song
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana
| | - Fatma M Aboulnasr
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana
| | | | - Nathan Shores
- Department of Gastroenterology and Hepatology, Tulane University School of Medicine, New Orleans, Louisiana
| | - William C Wimley
- Department of Biochemistry, Tulane University School of Medicine, New Orleans, Louisiana
| | - Shuanghu Liu
- Department of Medicine and Pathology, University of Utah School of Medicine, Salt Lake City, Utah
| | - Curt H Hagedorn
- Department of Medicine and Pathology, University of Utah School of Medicine, Salt Lake City, Utah
| | - Serge Y Fuchs
- Department of Animal Biology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Tong Wu
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana
| | - Luis A Balart
- Department of Gastroenterology and Hepatology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Srikanta Dash
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana.
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14
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Kong L, Liu K, Zhang YZ, Jin M, Wu BR, Wang WZ, Li W, Nan YM, Chen YH. Downregulation of TIPE2 mRNA expression in peripheral blood mononuclear cells from patients with chronic hepatitis C. Hepatol Int 2013. [DOI: 10.1007/s12072-013-9435-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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