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Carriere J, Rao Y, Liu Q, Lin X, Zhao J, Feng P. Post-translational Control of Innate Immune Signaling Pathways by Herpesviruses. Front Microbiol 2019; 10:2647. [PMID: 31798565 PMCID: PMC6868034 DOI: 10.3389/fmicb.2019.02647] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/30/2019] [Indexed: 12/21/2022] Open
Abstract
Herpesviruses constitute a large family of disease-causing DNA viruses. Each herpesvirus strain is capable of infecting particular organisms with a specific cell tropism. Upon infection, pattern recognition receptors (PRRs) recognize conserved viral features to trigger signaling cascades that culminate in the production of interferons and pro-inflammatory cytokines. To invoke a proper immune response while avoiding collateral tissue damage, signaling proteins involved in these cascades are tightly regulated by post-translational modifications (PTMs). Herpesviruses have developed strategies to subvert innate immune signaling pathways in order to ensure efficient viral replication and achieve persistent infection. The ability of these viruses to control the proteins involved in these signaling cascades post-translationally, either directly via virus-encoded enzymes or indirectly through the deregulation of cellular enzymes, has been widely reported. This ability provides herpesviruses with a powerful tool to shut off or restrict host antiviral and inflammatory responses. In this review, we highlight recent findings on the herpesvirus-mediated post-translational control along PRR-mediated signaling pathways.
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Affiliation(s)
| | | | | | | | | | - Pinghui Feng
- Section of Infection and Immunity, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, United States
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52
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Alandijany T. Host Intrinsic and Innate Intracellular Immunity During Herpes Simplex Virus Type 1 (HSV-1) Infection. Front Microbiol 2019; 10:2611. [PMID: 31781083 PMCID: PMC6856869 DOI: 10.3389/fmicb.2019.02611] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 10/28/2019] [Indexed: 12/20/2022] Open
Abstract
When host cells are invaded by viruses, they deploy multifaceted intracellular defense mechanisms to control infections and limit the damage they may cause. Host intracellular antiviral immunity can be classified into two main branches: (i) intrinsic immunity, an interferon (IFN)-independent antiviral response mediated by constitutively expressed cellular proteins (so-called intrinsic host restriction factors); and (ii) innate immunity, an IFN-dependent antiviral response conferred by IFN-stimulated gene (ISG) products, which are (as indicated by their name) upregulated in response to IFN secretion following the recognition of pathogen-associated molecular patterns (PAMPs) by host pattern recognition receptors (PRRs). Recent evidence has demonstrated temporal regulation and specific viral requirements for the induction of these two arms of immunity during herpes simplex virus type 1 (HSV-1) infection. Moreover, they exert differential antiviral effects to control viral replication. Although they are distinct from one another, the words "intrinsic" and "innate" have been interchangeably and/or simultaneously used in the field of virology. Hence, the aims of this review are to (1) elucidate the current knowledge about host intrinsic and innate immunity during HSV-1 infection, (2) clarify the recent advances in the understanding of their regulation and address the distinctions between them with respect to their induction requirements and effects on viral infection, and (3) highlight the key roles of the viral E3 ubiquitin ligase ICP0 in counteracting both aspects of immunity. This review emphasizes that intrinsic and innate immunity are temporally and functionally distinct arms of host intracellular immunity during HSV-1 infection; the findings are likely pertinent to other clinically important viral infections.
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Affiliation(s)
- Thamir Alandijany
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
- Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
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53
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Roy A, Ghosh A, Kumar B, Chandran B. IFI16, a nuclear innate immune DNA sensor, mediates epigenetic silencing of herpesvirus genomes by its association with H3K9 methyltransferases SUV39H1 and GLP. eLife 2019; 8:49500. [PMID: 31682228 PMCID: PMC6855800 DOI: 10.7554/elife.49500] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 11/01/2019] [Indexed: 12/25/2022] Open
Abstract
IFI16, an innate immune DNA sensor, recognizes the nuclear episomal herpes viral genomes and induces the inflammasome and interferon-β responses. IFI16 also regulates cellular transcription and act as a DNA virus restriction factor. IFI16 knockdown disrupted the latency of Kaposi’s sarcoma associated herpesvirus (KSHV) and induced lytic transcripts. However, the mechanism of IFI16’s transcription regulation is unknown. Here, we show that IFI16 is in complex with the H3K9 methyltransferase SUV39H1 and GLP and recruits them to the KSHV genome during de novo infection and latency. The resulting depositions of H3K9me2/me3 serve as a docking site for the heterochromatin-inducing HP1α protein leading into the IFI16-dependent epigenetic modifications and silencing of KSHV lytic genes. These studies suggest that IFI16’s interaction with H3K9MTases is one of the potential mechanisms by which IFI16 regulates transcription and establish an important paradigm of an innate immune sensor’s involvement in epigenetic silencing of foreign DNA.
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Affiliation(s)
- Arunava Roy
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, United States
| | - Anandita Ghosh
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, United States
| | - Binod Kumar
- Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, United States
| | - Bala Chandran
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, United States
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54
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Li D, Wu R, Guo W, Xie L, Qiao Z, Chen S, Zhu J, Huang C, Huang J, Chen B, Qin Y, Xu F, Ma F. STING-Mediated IFI16 Degradation Negatively Controls Type I Interferon Production. Cell Rep 2019; 29:1249-1260.e4. [PMID: 31665637 DOI: 10.1016/j.celrep.2019.09.069] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 07/22/2019] [Accepted: 09/20/2019] [Indexed: 12/17/2022] Open
Abstract
γ-interferon-inducible protein-16 (IFI16), a key DNA sensor, triggers downstream STING-dependent type I interferon (IFN-I) production and antiviral immunity. However, it is still unclear how to negatively regulate IFI16 to avoid excessive IFN-I production and autoimmunity. Here, we find that STING directly interacts with IFI16 and facilitates IFI16 degradation via the ubiquitin-proteasome pathway by recruiting the E3 ligase TRIM21. The 1-pyrin region of IFI16 is responsible for the IFI16-STING interaction, and the first three lysines in the N-terminal region of IFI16 are the key sites that lead to STING-mediated IFI16 ubiquitination and degradation. Compared to wild-type IFI16, a higher level of viral DNA triggered IFN-β and antiviral IFN-stimulated gene expression, and thus less HSV-1 infection, was observed in the cells transfected with IFI16-K3/4/6R, an IFI16 mutant that is resistant to degradation. STING-mediated negative feedback regulation of IFI16 restricts IFN-I overproduction during antiviral immunity to avoid autoimmune diseases.
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Affiliation(s)
- Dapei Li
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China; Suzhou Institute of Systems Medicine, Suzhou 215123, China
| | - Rongsheng Wu
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China; Suzhou Institute of Systems Medicine, Suzhou 215123, China
| | - Wen Guo
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China; Suzhou Institute of Systems Medicine, Suzhou 215123, China
| | - Lifen Xie
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China; Suzhou Institute of Systems Medicine, Suzhou 215123, China
| | - Zigang Qiao
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China; Suzhou Institute of Systems Medicine, Suzhou 215123, China
| | - Shengchuan Chen
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China; Suzhou Institute of Systems Medicine, Suzhou 215123, China; Department of Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Jingfei Zhu
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China; Suzhou Institute of Systems Medicine, Suzhou 215123, China
| | - Chaohao Huang
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China; Suzhou Institute of Systems Medicine, Suzhou 215123, China; Department of Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Jian Huang
- Department of Emergency, The First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Bicheng Chen
- Department of Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Yanghua Qin
- Department of Laboratory Diagnosis, Changhai Hospital of the Second Military Medical University, Shanghai 200433, China
| | - Feng Xu
- Department of Infectious Diseases, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Feng Ma
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China; Suzhou Institute of Systems Medicine, Suzhou 215123, China.
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Cadena C, Hur S. Filament-like Assemblies of Intracellular Nucleic Acid Sensors: Commonalities and Differences. Mol Cell 2019; 76:243-254. [PMID: 31626748 PMCID: PMC6880955 DOI: 10.1016/j.molcel.2019.09.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/13/2019] [Accepted: 09/19/2019] [Indexed: 12/25/2022]
Abstract
Self versus non-self discrimination by innate immune sensors is critical for mounting effective immune responses against pathogens while avoiding harmful auto-inflammatory reactions against the host. Foreign DNA and RNA sensors must discriminate between self versus non-self nucleic acids, despite their shared building blocks and similar physicochemical properties. Recent structural and biochemical studies suggest that multiple steps of filament-like assembly are required for the functions of several nucleic acid sensors. Here, we discuss ligand discrimination and oligomerization of RIG-I-like receptors, AIM2-like receptors, and cGAS. We discuss how filament-like assembly allows for robust and accurate discrimination of self versus non-self nucleic acids and how these assemblies enable sensing of multiple distinct features in foreign nucleic acids, including structure, length, and modifications. We also discuss how individual receptors differ in their assembly and disassembly mechanisms and how these differences contribute to the diversity in nucleic acid specificity and pathogen detection strategies.
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Affiliation(s)
- Cristhian Cadena
- Program in Virology, Division of Medical Sciences, Harvard Medical School, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA
| | - Sun Hur
- Program in Virology, Division of Medical Sciences, Harvard Medical School, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA.
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56
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Cao L, Ji Y, Zeng L, Liu Q, Zhang Z, Guo S, Guo X, Tong Y, Zhao X, Li CM, Chen Y, Guo D. P200 family protein IFI204 negatively regulates type I interferon responses by targeting IRF7 in nucleus. PLoS Pathog 2019; 15:e1008079. [PMID: 31603949 PMCID: PMC6818788 DOI: 10.1371/journal.ppat.1008079] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 10/29/2019] [Accepted: 09/12/2019] [Indexed: 01/19/2023] Open
Abstract
Interferon-inducible p200 family protein IFI204 was reported to be involved in DNA sensing, and subsequently induces the production of type I interferons and proinflammatory mediators. However, its function in the regulation of antiviral innate immune signaling pathway remains unclear. Here we reported a novel role of IFI204 that specifically inhibits the IRF7-mediated type I interferons response during viral infection. IFI204 and other p200 family proteins are highly expressed in mouse hepatitis coronavirus-infected bone marrow-derived dendritic cells. The abundant IFI204 could significantly interact with IRF7 in nucleus by its HIN domain and prevent the binding of IRF7 with its corresponding promoter. Moreover, other p200 family proteins that possess HIN domain could also inhibit the IRF7-mediated type I interferons. These results reveal that, besides the positive regulation function in type I interferon response at the early stage of DNA virus infection, the interferon-inducible p200 family proteins such as IFI204 could also negatively regulate the IRF7-mediated type I interferon response after RNA virus infection to avoid unnecessary host damage from hyper-inflammatory responses. The regulation of type I interferon signaling pathway is dynamic sequential processes and must be tightly regulated to keep balance between antiviral immune and hyper-inflammatory responses. The precise regulation mechanisms of the innate immune signaling pathway are still worth studying. Here, we found a novel role of the interferon-inducible p200 family protein IFI204 that specifically inhibits the IRF7-mediated type I interferon production by negative control of the transcriptional activity of IRF7 in the nucleus at the late stage of RNA virus infection. Previous studies showed that IFI204 is involved in DNA sensing during DNA virus infection to initiate antiviral immune responses. We demonstrate that IFI204 can inhibit IRF7-mediated activation of type I IFN responses induced by RNA virus infection, which is in contrast with its role in IRF3 activation in cGAS-STING DNA sensing pathway during DNA virus infection. Such negative regulation may help to avoid hyper-inflammatory responses induced by the over-activated IRF7-mediated type I interferons at late stage of the viral infection. Thus, the current study sheds light on the regulation roles of p200 family proteins and the accurate regulation system of type I interferons signaling pathway.
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Affiliation(s)
- Liu Cao
- State Key Laboratory of Virology, Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yanxi Ji
- State Key Laboratory of Virology, Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China
- School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Lanyi Zeng
- State Key Laboratory of Virology, Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Qianyun Liu
- State Key Laboratory of Virology, Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhen Zhang
- State Key Laboratory of Virology, Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Shuting Guo
- School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Xiaolong Guo
- College of Life Sciences, Wuhan University, Wuhan, China
| | - Yongjia Tong
- College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiaolu Zhao
- College of Life Sciences, Wuhan University, Wuhan, China
| | - Chun-Mei Li
- School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Yu Chen
- State Key Laboratory of Virology, Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China
- * E-mail: (YC); (DG)
| | - Deyin Guo
- School of Medicine, Sun Yat-sen University, Guangzhou, China
- * E-mail: (YC); (DG)
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57
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Amin I, Younas S, Afzal S, Shahid M, Idrees M. Herpes Simplex Virus Type 1 and Host Antiviral Immune Responses: An Update. Viral Immunol 2019; 32:424-429. [PMID: 31599707 DOI: 10.1089/vim.2019.0097] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Herpes simplex virus type 1 (HSV-1) infection activates a rapid stimulation of host innate immune responses and a delicate interplay between virus and host immune elements regulates the whole events. Although host immune elements play well in limiting the HSV-1 infection by interfering viral replication, they are still unable to remove the virus completely, because HSV-1 proteins are efficient enough to bypass the host antiviral immune responses and virus succeed to reactivate again from latency at opportune time. Type 1 interferon signaling pathway is the central point of innate immunity along with some of the activated neutrophils, monocytes, macrophages, and dendritic cells, and some natural killer cells play role, while the CD8+ T cells are crucial in adaptive immunity. In this review, the current knowledge of host and HSV-1 interaction has been described that how the host antiviral immune responses occur and what are the mechanisms of viral evasion adapted by virus to counteract with both arms of immunity.
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Affiliation(s)
- Iram Amin
- Division of Molecular Virology and Infectious Diseases, Centre of Excellence in Molecular Biology (CEMB), University of the Punjab, Lahore, Pakistan
| | - Saima Younas
- Molecular Diagnostic Lab, Centre for Applied Molecular Biology (CAMB), University of the Punjab, Lahore, Pakistan
| | - Samia Afzal
- Division of Molecular Virology and Infectious Diseases, Centre of Excellence in Molecular Biology (CEMB), University of the Punjab, Lahore, Pakistan
| | - Muhammad Shahid
- Division of Molecular Virology and Infectious Diseases, Centre of Excellence in Molecular Biology (CEMB), University of the Punjab, Lahore, Pakistan
| | - Muhammad Idrees
- Division of Molecular Virology and Infectious Diseases, Centre of Excellence in Molecular Biology (CEMB), University of the Punjab, Lahore, Pakistan
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58
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Full F, Ensser A. Early Nuclear Events after Herpesviral Infection. J Clin Med 2019; 8:jcm8091408. [PMID: 31500286 PMCID: PMC6780142 DOI: 10.3390/jcm8091408] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 08/29/2019] [Accepted: 09/03/2019] [Indexed: 12/18/2022] Open
Abstract
Herpesviruses are important pathogens that can cause significant morbidity and mortality in the human population. Herpesviruses have a double-stranded DNA genome, and viral genome replication takes place inside the nucleus. Upon entering the nucleus, herpesviruses have to overcome the obstacle of cellular proteins in order to enable viral gene expression and genome replication. In this review, we want to highlight cellular proteins that sense incoming viral genomes of the DNA-damage repair (DDR) pathway and of PML-nuclear bodies (PML-NBs) that all can act as antiviral restriction factors within the first hours after the viral genome is released into the nucleus. We show the function and significance of both nuclear DNA sensors, the DDR and PML-NBs, and demonstrate for three human herpesviruses of the alpha-, beta- and gamma-subfamilies, HSV-1, HCMV and KSHV respectively, how viral tegument proteins antagonize these pathways.
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Affiliation(s)
- Florian Full
- Institute for Clinical and Molecular Virology, University Hospital Erlangen, Friedrich Alexander University Erlangen-Nuremberg, 91054 Erlangen, Germany.
| | - Armin Ensser
- Institute for Clinical and Molecular Virology, University Hospital Erlangen, Friedrich Alexander University Erlangen-Nuremberg, 91054 Erlangen, Germany.
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59
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Coulon PG, Dhanushkodi N, Prakash S, Srivastava R, Roy S, Alomari NI, Nguyen AM, Warsi WR, Ye C, Carlos-Cruz EA, Mai UT, Cruel AC, Ekmekciyan KM, Pearlman E, BenMohamed L. NLRP3, NLRP12, and IFI16 Inflammasomes Induction and Caspase-1 Activation Triggered by Virulent HSV-1 Strains Are Associated With Severe Corneal Inflammatory Herpetic Disease. Front Immunol 2019; 10:1631. [PMID: 31367214 PMCID: PMC6644090 DOI: 10.3389/fimmu.2019.01631] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 07/01/2019] [Indexed: 12/15/2022] Open
Abstract
The crosstalk between the host's inflammasome system and the invading virulent/less-virulent viruses determines the outcome of the ensuing inflammatory response. An appropriate activation of inflammasomes triggers antiviral inflammatory responses that clear the virus and heal the inflamed tissue. However, an aberrant activation of inflammasomes can result in a harmful and overwhelming inflammation that could damage the infected tissue. The underlying host's immune mechanisms and the viral virulent factors that impact severe clinical inflammatory disease remain to be fully elucidated. In this study, we used herpes simplex virus type 1 (HSV-1), the causative agent of corneal inflammatory herpetic disease, as a model pathogen to determine: (i) Whether and how the virulence of a virus affects the type and the activation level of the inflammasomes; and (ii) How triggering specific inflammasomes translates into protective or damaging inflammatory response. We showed that, in contrast to the less-virulent HSV-1 strains (RE, F, KOS, and KOS63), corneal infection of B6 mice with the virulent HSV-1 strains (McKrae, 17 or KOS79): (i) Induced simultaneous expression of the NLRP3, NLRP12, and IFI16 inflammasomes; (ii) Increased production of the biologically active Caspase-1 and pro-inflammatory cytokines IL-1β and IL-18; (iii) Heightened recruitment into the inflamed cornea of CD45highLy6C+Ly6G-F4/80+CD11b+CD11c- inflammatory monocytes and CD45highCD11b+F4/80-Ly6GhiLy6Cmed neutrophils; and (iv) This intensified inflammatory response was associated with a severe corneal herpetic disease, irrespective of the level of virus replication in the cornea. Similarly, in vitro infection of human corneal epithelial cells and human monocytic THP-1 cells with the virulent HSV-1 strains triggered a synchronized early expression of NLRP3, NLRP12 and IFI16, 2 h post-infection, associated with formation of single and dense specks of the adapter molecule ASC in HSV(+) cells, but not in the neighboring bystander HSV(-) cells. This was associated with increased cleavages of Caspase-1, IL-1β, and IL-18. These findings suggest a previously unappreciated role of viral virulence in a synchronized early induction of the NLRP3, NLRP12, and IFI16 inflammasomes that lead to a damaging inflammatory response. A potential role of common virus virulent factors that stimulate this harmful inflammatory corneal disease is currently under investigation.
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Affiliation(s)
- Pierre-Gregoire Coulon
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Nisha Dhanushkodi
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Swayam Prakash
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Ruchi Srivastava
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Soumyabrata Roy
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Nuha I. Alomari
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Angela M. Nguyen
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Wasay R. Warsi
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Caitlin Ye
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Edgar A. Carlos-Cruz
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Uyen T. Mai
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Audrey C. Cruel
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Keysi M. Ekmekciyan
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Eric Pearlman
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
- School of Medicine, Institute for Immunology, University of California, Irvine, Irvine, CA, United States
| | - Lbachir BenMohamed
- Laboratory of Cellular and Molecular Immunology, School of Medicine, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
- School of Medicine, Institute for Immunology, University of California, Irvine, Irvine, CA, United States
- Department of Molecular Biology and Biochemistry, School of Medicine, University of California, Irvine, Irvine, CA, United States
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60
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Epstein-Barr Virus and Innate Immunity: Friends or Foes? Microorganisms 2019; 7:microorganisms7060183. [PMID: 31238570 PMCID: PMC6617214 DOI: 10.3390/microorganisms7060183] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 06/20/2019] [Accepted: 06/22/2019] [Indexed: 12/16/2022] Open
Abstract
Epstein–Barr virus (EBV) successfully persists in the vast majority of adults but causes lymphoid and epithelial malignancies in a small fraction of latently infected individuals. Innate immunity is the first-line antiviral defense, which EBV has to evade in favor of its own replication and infection. EBV uses multiple strategies to perturb innate immune signaling pathways activated by Toll-like, RIG-I-like, NOD-like, and AIM2-like receptors as well as cyclic GMP-AMP synthase. EBV also counteracts interferon production and signaling, including TBK1-IRF3 and JAK-STAT pathways. However, activation of innate immunity also triggers pro-inflammatory response and proteolytic cleavage of caspases, both of which exhibit proviral activity under some circumstances. Pathogenic inflammation also contributes to EBV oncogenesis. EBV activates NFκB signaling and induces pro-inflammatory cytokines. Through differential modulation of the proviral and antiviral roles of caspases and other host factors at different stages of infection, EBV usurps cellular programs for death and inflammation to its own benefits. The outcome of EBV infection is governed by a delicate interplay between innate immunity and EBV. A better understanding of this interplay will instruct prevention and intervention of EBV-associated cancers.
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61
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Inflammation research sails through the sea of immunology to reach immunometabolism. Int Immunopharmacol 2019; 73:128-145. [PMID: 31096130 DOI: 10.1016/j.intimp.2019.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 04/18/2019] [Accepted: 05/01/2019] [Indexed: 02/08/2023]
Abstract
Inflammation occurs as a result of acute trauma, invasion of the host by different pathogens, pathogen-associated molecular patterns (PAMPs) or chronic cellular stress generating damage-associated molecular patterns (DAMPs). Thus inflammation may occur under both sterile inflammatory conditions including certain cancers, autoimmune or autoinflammatory diseases (Rheumatic arthritis (RA)) and infectious diseases including sepsis, pneumonia-associated acute lung inflammation (ALI) or acute respiratory distress syndrome (ARDS). The pathogenesis of inflammation involves dysregulation of an otherwise protective immune response comprising of various innate and adaptive immune cells and humoral (cytokines and chemokines) mediators secreted by these immune cells upon the activation of signaling mechanisms regulated by the activation of different pattern recognition receptors (PRRs). However, the pro-inflammatory and anti-inflammatory action of these immune cells is determined by the metabolic stage of the immune cells. The metabolic process of immune cells is called immunometabolism and its shift determined by inflammatory stimuli is called immunometabolic reprogramming. The article focuses on the involvement of various immune cells generating the inflammation, their interaction, immunometabolic reprogramming, and the therapeutic targeting of the immunometabolism to manage inflammation.
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62
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Tognarelli EI, Palomino TF, Corrales N, Bueno SM, Kalergis AM, González PA. Herpes Simplex Virus Evasion of Early Host Antiviral Responses. Front Cell Infect Microbiol 2019; 9:127. [PMID: 31114761 PMCID: PMC6503643 DOI: 10.3389/fcimb.2019.00127] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 04/10/2019] [Indexed: 12/21/2022] Open
Abstract
Herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2) have co-evolved with humans for thousands of years and are present at a high prevalence in the population worldwide. HSV infections are responsible for several illnesses including skin and mucosal lesions, blindness and even life-threatening encephalitis in both, immunocompetent and immunocompromised individuals of all ages. Therefore, diseases caused by HSVs represent significant public health burdens. Similar to other herpesviruses, HSV-1 and HSV-2 produce lifelong infections in the host by establishing latency in neurons and sporadically reactivating from these cells, eliciting recurrences that are accompanied by viral shedding in both, symptomatic and asymptomatic individuals. The ability of HSVs to persist and recur in otherwise healthy individuals is likely given by the numerous virulence factors that these viruses have evolved to evade host antiviral responses. Here, we review and discuss molecular mechanisms used by HSVs to evade early innate antiviral responses, which are the first lines of defense against these viruses. A comprehensive understanding of how HSVs evade host early antiviral responses could contribute to the development of novel therapies and vaccines to counteract these viruses.
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Affiliation(s)
- Eduardo I Tognarelli
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Tomás F Palomino
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nicolás Corrales
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Susan M Bueno
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alexis M Kalergis
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Endocrinología, Facultad de Medicina, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo A González
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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63
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Coevolution pays off: Herpesviruses have the license to escape the DNA sensing pathway. Med Microbiol Immunol 2019; 208:495-512. [PMID: 30805724 DOI: 10.1007/s00430-019-00582-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 02/09/2019] [Indexed: 01/20/2023]
Abstract
Early detection of viral invasion by pattern recognition receptors (PRR) is crucial for the induction of a rapid and efficient immune response. Cytosolic DNA sensors are the most recently described class of PRR, and induce transcription of type I interferons (IFN) and proinflammatory cytokines via the key adaptor protein stimulator of interferon genes (STING). Herpesviruses are a family of large DNA viruses widely known for their immense arsenal of proteins dedicated to manipulating and evading host immune responses. Tantamount to the significant role played by DNA sensors and STING in innate immune responses, herpesviruses have in turn evolved a range of mechanisms targeting virtually every step of this key signaling pathway. Strikingly, some herpesviruses also take advantage of this pathway to promote their own replication. In this review, we will summarize the current understanding of DNA sensing and subsequent induction of signaling and transcription, and showcase the close adaptation of herpesviruses to their host reflected by the myriad of viral proteins dedicated to modulating this critical innate immune pathway.
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64
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Botto S, Abraham J, Mizuno N, Pryke K, Gall B, Landais I, Streblow DN, Fruh KJ, DeFilippis VR. Human Cytomegalovirus Immediate Early 86-kDa Protein Blocks Transcription and Induces Degradation of the Immature Interleukin-1β Protein during Virion-Mediated Activation of the AIM2 Inflammasome. mBio 2019; 10:e02510-18. [PMID: 30755509 PMCID: PMC6372796 DOI: 10.1128/mbio.02510-18] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 01/02/2019] [Indexed: 12/11/2022] Open
Abstract
Secretion of interleukin-1β (IL-1β) represents a fundamental innate immune response to microbial infection that, at the molecular level, occurs following activation of proteolytic caspases that cleave the immature protein into a secretable form. Human cytomegalovirus (HCMV) is the archetypal betaherpesvirus that is invariably capable of lifelong infection through the activity of numerous virally encoded immune evasion phenotypes. Innate immune pathways responsive to cytoplasmic double-stranded DNA (dsDNA) are known to be activated in response to contact between HCMV and host cells. Here, we used clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated protein 9 (Cas9) genome editing to demonstrate that the dsDNA receptor absent in melanoma 2 (AIM2) is required for secretion of IL-1β following HCMV infection. Furthermore, dsDNA-responsive innate signaling induced by HCMV infection that leads to activation of the type I interferon response is also shown, unexpectedly, to play a contributory role in IL-1β secretion. Importantly, we also show that rendering virus particles inactive by UV exposure leads to substantially increased IL-1β processing and secretion and that live HCMV can inhibit this, suggesting the virus encodes factors that confer an inhibitory effect on this response. Further examination revealed that ectopic expression of the immediate early (IE) 86-kDa protein (IE86) is actually associated with a block in transcription of the pro-IL-1β gene and, independently, diminishment of the immature protein. Overall, these results reveal two new and distinct phenotypes conferred by the HCMV IE86 protein, as well as an unusual circumstance in which a single herpesviral protein exhibits inhibitory effects on multiple molecular processes within the same innate immune response.IMPORTANCE Persistent infection with HCMV is associated with the operation of diverse evasion phenotypes directed at antiviral immunity. Obstruction of intrinsic and innate immune responses is typically conferred by viral proteins either associated with the viral particle or expressed immediately after entry. In line with this, numerous phenotypes are attributed to the HCMV IE86 protein that involve interference with innate immune processes via transcriptional and protein-directed mechanisms. We describe novel IE86-mediated phenotypes aimed at virus-induced secretion of IL-1β. Intriguingly, while many viruses target the function of the molecular scaffold required for IL-1β maturation to prevent this response, we find that HCMV and IE86 target the IL-1β protein specifically. Moreover, we show that IE86 impairs both the synthesis of the IL-1β transcript and the stability of the immature protein. This indicates an unusual phenomenon in which a single viral protein exhibits two molecularly separate evasion phenotypes directed at a single innate cytokine.
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Affiliation(s)
- Sara Botto
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Portland, Oregon, USA
| | - Jinu Abraham
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Portland, Oregon, USA
| | - Nobuyo Mizuno
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Portland, Oregon, USA
| | - Kara Pryke
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Portland, Oregon, USA
| | - Bryan Gall
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Portland, Oregon, USA
| | - Igor Landais
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Portland, Oregon, USA
| | - Daniel N Streblow
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Portland, Oregon, USA
| | - Klaus J Fruh
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Portland, Oregon, USA
| | - Victor R DeFilippis
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Portland, Oregon, USA
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65
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Meng W, Wang XJ, Wang HCR. Targeting nuclear proteins for control of viral replication. Crit Rev Microbiol 2019; 45:495-513. [DOI: 10.1080/1040841x.2018.1553848] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Wen Meng
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Xiao-Jia Wang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Hwa-Chain Robert Wang
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, The University of Tennessee, Knoxville, USA
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66
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Kumar S, Chera JS, Vats A, De S. Nature of selection varies on different domains of IFI16-like PYHIN genes in ruminants. BMC Evol Biol 2019; 19:26. [PMID: 30654734 PMCID: PMC6335826 DOI: 10.1186/s12862-018-1334-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 12/17/2018] [Indexed: 12/11/2022] Open
Abstract
Background ALRs (AIM2-like Receptors) are germline encoded PRRs that belong to PYHIN gene family of cytokines, which are having signature N-terminal PYD (Pyrin, PAAD or DAPIN) domain and C-terminal HIN-200 (hematopoietic, interferon-inducible nuclear protein with 200 amino acid repeat) domain joined by a linker region. The positively charged HIN-200 domain senses and binds with negatively charged phosphate groups of single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) purely through electrostatic attractions. On the other hand, PYD domain interacts homotypically with a PYD domain of other mediators to pass the signals to effector molecules downwards the pathways for inflammatory responses. There is remarkable inter-specific diversity in the numbers of functional PYHIN genes e.g. one in cow, five in human, thirteen in mice etc., while there is a unique loss of PYHIN genes in the bat genomes which was revealed by Ahn et al. (2016) by studying genomes of ten different bat species belonging to sub-orders yinpterochiroptera and yangochiroptera. The conflicts between host and pathogen interfaces are compared with “Red queen’s arms race” which is also described as binding seeking dynamics and binding avoidance dynamics. As a result of this never-ending rivalry, eukaryotes developed PRRs as antiviral mechanism while viruses developed counter mechanisms to evade host immune defense. The PYHIN receptors are directly engaged with pathogenic molecules, so these should have evolved under the influence of selection pressures. In the current study, we investigated the nature of selection pressure on different domain types of IFI16-like (IFI16-L) PYHIN genes in ruminants. Results Three transcript variants of the IFI16-like gene were found in PBMCs of ruminant animals-water buffalo, zebu cattle, goat, and sheep. The IFI16-like gene has one N-terminal PYD domain and one C-terminal HIN-200 domain, separated by an inter-domain linker region. HIN domain and inter-domain region are positively selected while the PYD domain is under the influence of purifying selection. Conclusion Herein, we conclude that the nature of selection pressure varies on different parts (PYD domain, HIN domain, and inter-domain linker region) of IFI16-like PYHIN genes in the ruminants. This data can be useful to predict the molecular determinants of pathogen interactions. Electronic supplementary material The online version of this article (10.1186/s12862-018-1334-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sushil Kumar
- Animal Genomics Laboratory, Animal Biotechnology Centre, National Dairy Research Institute, Karnal, Haryana, 132001, India
| | - Jatinder Singh Chera
- Animal Genomics Laboratory, Animal Biotechnology Centre, National Dairy Research Institute, Karnal, Haryana, 132001, India
| | - Ashutosh Vats
- Animal Genomics Laboratory, Animal Biotechnology Centre, National Dairy Research Institute, Karnal, Haryana, 132001, India
| | - Sachinandan De
- Animal Genomics Laboratory, Animal Biotechnology Centre, National Dairy Research Institute, Karnal, Haryana, 132001, India.
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67
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Lupfer CR, Rippee-Brooks MD, Anand PK. Common Differences: The Ability of Inflammasomes to Distinguish Between Self and Pathogen Nucleic Acids During Infection. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 344:139-172. [PMID: 30798987 DOI: 10.1016/bs.ircmb.2018.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The innate immune system detects the presence of pathogens based on detection of non-self. In other words, most pathogens possess intrinsic differences that can distinguish them from host cells. For example, bacteria and fungi have cell walls comprised of peptidoglycan and carbohydrates (like mannans), respectively. Germline encoded pattern recognition receptors (PRRs) of the Toll-like receptor (TLR) and C-type lectin receptor (CLR) family have the ability to detect such unique pathogen associated features. However, some TLRs and members of the RIG-I-like receptor (RLR), NOD-like receptor (NLR), or AIM2-like receptor (ALR) family can sense pathogen invasion based on pathogen nucleic acids. Nucleic acids are not unique to pathogens, thus raising the question of how such PRRs evolved to detect pathogens but not self. In this chapter, we will examine the PRRs that sense pathogen nucleic acids and subsequently activate the inflammasome signaling pathway. We will examine the selective mechanisms by which these receptors distinguish pathogens from "self" and discuss the importance of such pathways in disease development in animal models and human patients.
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Affiliation(s)
- Christopher R Lupfer
- Department of Biology, Missouri State University, Springfield, MO, United States.
| | | | - Paras K Anand
- Infectious Diseases and Immunity, Imperial College London, London, United Kingdom.
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68
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Khan S, Godfrey V, Zaki MH. Cytosolic Nucleic Acid Sensors in Inflammatory and Autoimmune Disorders. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 344:215-253. [PMID: 30798989 DOI: 10.1016/bs.ircmb.2018.10.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Innate immunity employs germline-encoded pattern recognition receptors (PRRs) to sense microbial pattern molecules. Recognition of pathogen-associated molecular patterns (PAMPs) by various PPRs located on the cell membrane or in the cytosol leads to the activation of cell signaling pathways and production of inflammatory mediators. Nucleic acids including DNA, RNA, and their derivatives are potent PAMPs which can be recognized by multiple PRRs to induce inflammatory responses. While nucleic acid sensors can also sense endogenous nucleic acids, they are capable of discriminating self from non-self. However, defects in nucleic acid sensing PRRs or dysregulation of nucleic acid sensing signaling pathways may cause excessive activation of the immune system resulting in the development of inflammatory and autoimmune diseases. This review will discuss the major pathways for sensing intracellular nucleic acids and how defects in these nucleic acid sensing are associated with different kinds of autoimmune and inflammatory disorders.
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Affiliation(s)
- Shahanshah Khan
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Victoria Godfrey
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Md Hasan Zaki
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, United States.
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69
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Wei X, Lan K. Activation and counteraction of antiviral innate immunity by KSHV: an Update. Sci Bull (Beijing) 2018; 63:1223-1234. [PMID: 30906617 PMCID: PMC6426151 DOI: 10.1016/j.scib.2018.07.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The innate immune responses triggering production of type I interferons and inflammatory cytokines constitute a nonspecific innate resistance that eliminates invading pathogens including viruses. The activation of innate immune signaling through pattern recognition receptors (PRRs) is by sensing pathogen-associated molecular patterns derived from viruses. According to their distribution within cells, PRRs are classified into three types of receptors: membrane, cytoplasmic, and nuclear. Kaposi's sarcoma-associated herpesvirus (KSHV), a large DNA virus, replicates in the nucleus. Its genome is protected by capsid proteins during transport in the cytosol. Multiple PRRs are involved in KSHV recognition. To successfully establish latent infection, KSHV has evolved to manipulate different aspects of the host antiviral innate immune responses. This review presents recent advances in our understanding about the activation of the innate immune signaling in response to infection of KSHV. It also reviews the evasion strategies used by KSHV to subvert host innate immune detection for establishing a persistent infection.
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Affiliation(s)
| | - Ke Lan
- Corresponding author. (K. Lan)
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70
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Cytosolic Recognition of Microbes and Pathogens: Inflammasomes in Action. Microbiol Mol Biol Rev 2018; 82:82/4/e00015-18. [PMID: 30209070 DOI: 10.1128/mmbr.00015-18] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Infection is a dynamic biological process underpinned by a complex interplay between the pathogen and the host. Microbes from all domains of life, including bacteria, viruses, fungi, and protozoan parasites, have the capacity to cause infection. Infection is sensed by the host, which often leads to activation of the inflammasome, a cytosolic macromolecular signaling platform that mediates the release of the proinflammatory cytokines interleukin-1β (IL-1β) and IL-18 and cleavage of the pore-forming protein gasdermin D, leading to pyroptosis. Host-mediated sensing of the infection occurs when pathogens inject or carry pathogen-associated molecular patterns (PAMPs) into the cytoplasm or induce damage that causes cytosolic liberation of danger-associated molecular patterns (DAMPs) in the host cell. Recognition of PAMPs and DAMPs by inflammasome sensors, including NLRP1, NLRP3, NLRC4, NAIP, AIM2, and Pyrin, initiates a cascade of events that culminate in inflammation and cell death. However, pathogens can deploy virulence factors capable of minimizing or evading host detection. This review presents a comprehensive overview of the mechanisms of microbe-induced activation of the inflammasome and the functional consequences of inflammasome activation in infectious diseases. We also explore the microbial strategies used in the evasion of inflammasome sensing at the host-microbe interaction interface.
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71
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Wang PH, Ye ZW, Deng JJ, Siu KL, Gao WW, Chaudhary V, Cheng Y, Fung SY, Yuen KS, Ho TH, Chan CP, Zhang Y, Kok KH, Yang W, Chan CP, Jin DY. Inhibition of AIM2 inflammasome activation by a novel transcript isoform of IFI16. EMBO Rep 2018; 19:embr.201845737. [PMID: 30104205 DOI: 10.15252/embr.201845737] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 07/13/2018] [Accepted: 07/23/2018] [Indexed: 12/28/2022] Open
Abstract
Mouse p202 is a disease locus for lupus and a dominant-negative inhibitor of AIM2 inflammasome activation. A human homolog of p202 has not been identified so far. Here, we report a novel transcript isoform of human IFI16-designated IFI16-β, which has a domain architecture similar to that of mouse p202. Like p202, IFI16-β contains two HIN domains, but lacks the pyrin domain. IFI16-β is ubiquitously expressed in various human tissues and cells. Its mRNA levels are also elevated in leukocytes of patients with lupus, virus-infected cells, and cells treated with interferon-β or phorbol ester. IFI16-β co-localizes with AIM2 in the cytoplasm, whereas IFI16-α is predominantly found in the nucleus. IFI16-β interacts with AIM2 to impede the formation of a functional AIM2-ASC complex. In addition, IFI16-β sequesters cytoplasmic dsDNA and renders it unavailable for AIM2 sensing. Enforced expression of IFI16-β inhibits the activation of AIM2 inflammasome, whereas knockdown of IFI16-β augments interleukin-1β secretion triggered by dsDNA but not dsRNA Thus, cytoplasm-localized IFI16-β is functionally equivalent to mouse p202 that exerts an inhibitory effect on AIM2 inflammasome.
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Affiliation(s)
- Pei-Hui Wang
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Zi-Wei Ye
- Department of Microbiology, The University of Hong Kong, Pokfulam, Hong Kong
| | - Jian-Jun Deng
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Kam-Leung Siu
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Wei-Wei Gao
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Vidyanath Chaudhary
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Yun Cheng
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Sin-Yee Fung
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Kit-San Yuen
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Ting-Hin Ho
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Ching-Ping Chan
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Yan Zhang
- Department of Pediatrics and Adolescent Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Kin-Hang Kok
- Department of Microbiology, The University of Hong Kong, Pokfulam, Hong Kong
| | - Wanling Yang
- Department of Pediatrics and Adolescent Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Chi-Ping Chan
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Dong-Yan Jin
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
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Mariggiò G, Koch S, Schulz TF. Kaposi sarcoma herpesvirus pathogenesis. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0275. [PMID: 28893942 PMCID: PMC5597742 DOI: 10.1098/rstb.2016.0275] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2017] [Indexed: 12/15/2022] Open
Abstract
Kaposi sarcoma herpesvirus (KSHV), taxonomical name human gammaherpesvirus 8, is a phylogenetically old human virus that co-evolved with human populations, but is now only common (seroprevalence greater than 10%) in sub-Saharan Africa, around the Mediterranean Sea, parts of South America and in a few ethnic communities. KSHV causes three human malignancies, Kaposi sarcoma, primary effusion lymphoma, and many cases of the plasmablastic form of multicentric Castleman's disease (MCD) as well as occasional cases of plasmablastic lymphoma arising from MCD; it has also been linked to rare cases of bone marrow failure and hepatitis. As it has colonized humans physiologically for many thousand years, cofactors are needed to allow it to unfold its pathogenic potential. In most cases, these include immune defects of genetic, iatrogenic or infectious origin, and inflammation appears to play an important role in disease development. Our much improved understanding of its life cycle and its role in pathogenesis should now allow us to develop new therapeutic strategies directed against key viral proteins or intracellular pathways that are crucial for virus replication or persistence. Likewise, its limited (for a herpesvirus) distribution and transmission should offer an opportunity for the development and use of a vaccine to prevent transmission. This article is part of the themed issue ‘Human oncogenic viruses’.
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Affiliation(s)
- Giuseppe Mariggiò
- Institute of Virology, Hannover Medical School, Carl Neuberg Strasse 1, 30625 Hannover, Germany.,German Centre for Infection Research, Hannover-Braunschweig site, Hannover, Germany
| | - Sandra Koch
- Institute of Virology, Hannover Medical School, Carl Neuberg Strasse 1, 30625 Hannover, Germany.,German Centre for Infection Research, Hannover-Braunschweig site, Hannover, Germany
| | - Thomas F Schulz
- Institute of Virology, Hannover Medical School, Carl Neuberg Strasse 1, 30625 Hannover, Germany .,German Centre for Infection Research, Hannover-Braunschweig site, Hannover, Germany
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73
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Abstract
Recognition of virus-derived nucleic acids by host pattern recognition receptors (PRRs) is crucial for early defense against viral infections. Recent studies revealed that PRRs also include several newly identified DNA sensors, most of which could activate the downstream adaptor stimulator of interferon genes (STING) and lead to the production of host antiviral factors. Herpes simplex virus 1 (HSV-1) is extremely successful in establishing effective infections, due to its capacity to counteract host innate antiviral responses. In this Gem, I summarize the most recent findings on the molecular mechanisms utilized by HSV-1 to target different steps of the cellular DNA-sensor-mediated antiviral signal pathway.
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Affiliation(s)
- Chunfu Zheng
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, Canada
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74
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p204 Is Required for Canonical Lipopolysaccharide-induced TLR4 Signaling in Mice. EBioMedicine 2018; 29:78-91. [PMID: 29472103 PMCID: PMC5925582 DOI: 10.1016/j.ebiom.2018.02.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 02/14/2018] [Accepted: 02/14/2018] [Indexed: 11/22/2022] Open
Abstract
p204, a murine member of an interferon-inducible p200 family, was reported to recognize intracellular viral and bacterial DNAs, however, its role in the innate immunity in vivo remains unknown due to the lack of p204-deficient animal models. In this study we first generated the p204−/− mice. Unexpectedly, p204 deficiency led to significant defect in extracellular LPS signaling in macrophages, as demonstrated by dramatic reductions of LPS-mediated IFN-β and pro-inflammatory cytokines. The serum levels of IFN-β and pro-inflammatory cytokines were also significantly reduced in p204−/− mice following LPS challenge. In addition, p204−/− mice were resistant to LPS-induced shock. LPS-activated NF-ĸB and IRF-3 pathways were all defective in p204-deficient macrophages. p204 binds to TLR4 through its Pyrin domain, and it is required for the dimerization of TLR4 following LPS-challenge. Collectively, p204 is a critical component of canonical LPS-TLR4 signaling pathway, and these studies also suggest that p204 could be a potential target to prevent and treat inflammatory and infectious diseases. p204 deficiency leads to significant defect in extracellular LPS signaling in macrophages. Serum levels of IFN-β and pro-inflammatory cytokines were also significantly reduced in p204-/- mice following LPS challenge. p204-/- mice were resistant to LPS-induced shock. p204 binds to TLR4 through its Pyrin domain, and it is required for the dimerization of TLR4 following LPS-challenge.
Effective anti-pathogenic responses, including production of type I IFNs and inflammatory response, are critical for host defense. p200 family members, including IFI16 and AIM2, have been reported to function as the sensors of pathogen components. However, investigation of their roles has largely focused on intracellular pathogen components, independent of extracellular pathogen receptors, such as TLRs. Here, we provide unexpected evidences demonstrating that p204, a murine counterpart of human IFI16, is required for extracellular but not intracellular LPS signaling. These results provide not only evidence of functional crosstalk and cooperation between intracellular p204 and extracellular LPS through TLR4 pathways in macrophage-mediated innate immunity, but also new insights into the mechanisms underlying p200 family proteins mediated antiviral and antibacterial infections.
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75
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Molecular requirements for sensing of intracellular microbial nucleic acids by the innate immune system. Cytokine 2017; 98:4-14. [DOI: 10.1016/j.cyto.2016.10.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 10/11/2016] [Indexed: 12/24/2022]
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The RNA helicase DDX46 inhibits innate immunity by entrapping m 6A-demethylated antiviral transcripts in the nucleus. Nat Immunol 2017; 18:1094-1103. [PMID: 28846086 DOI: 10.1038/ni.3830] [Citation(s) in RCA: 246] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 08/07/2017] [Indexed: 12/15/2022]
Abstract
DEAD-box (DDX) helicases are vital for the recognition of RNA and metabolism and are critical for the initiation of antiviral innate immunity. Modification of RNA is involved in many biological processes; however, its role in antiviral innate immunity has remained unclear. Here we found that nuclear DDX member DDX46 inhibited the production of type I interferons after viral infection. DDX46 bound Mavs, Traf3 and Traf6 transcripts (which encode signaling molecules involved in antiviral responses) via their conserved CCGGUU element. After viral infection, DDX46 recruited ALKBH5, an 'eraser' of the RNA modification N6-methyladenosine (m6A), via DDX46's DEAD helicase domain to demethylate those m6A-modified antiviral transcripts. It consequently enforced their retention in the nucleus and therefore prevented their translation and inhibited interferon production. DDX46 also suppressed antiviral innate immunity in vivo. Thus, DDX46 inhibits antiviral innate responses by entrapping selected antiviral transcripts in the nucleus by erasing their m6A modification, a modification normally required for export from the nucleus and translation.
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Baker PJ, De Nardo D, Moghaddas F, Tran LS, Bachem A, Nguyen T, Hayman T, Tye H, Vince JE, Bedoui S, Ferrero RL, Masters SL. Posttranslational Modification as a Critical Determinant of Cytoplasmic Innate Immune Recognition. Physiol Rev 2017; 97:1165-1209. [DOI: 10.1152/physrev.00026.2016] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 02/27/2017] [Accepted: 02/28/2017] [Indexed: 12/21/2022] Open
Abstract
Cell surface innate immune receptors can directly detect a variety of extracellular pathogens to which cytoplasmic innate immune sensors are rarely exposed. Instead, within the cytoplasm, the environment is rife with cellular machinery and signaling pathways that are indirectly perturbed by pathogenic microbes to activate intracellular sensors, such as pyrin, NLRP1, NLRP3, or NLRC4. Therefore, subtle changes in key intracellular processes such as phosphorylation, ubiquitination, and other pathways leading to posttranslational protein modification are key determinants of innate immune recognition in the cytoplasm. This concept is critical to establish the “guard hypothesis” whereby otherwise homeostatic pathways that keep innate immune sensors at bay are released in response to alterations in their posttranslational modification status. Originally identified in plants, evidence that a similar guardlike mechanism exists in humans has recently been identified, whereby a mutation that prevents phosphorylation of the innate immune sensor pyrin triggers a dominantly inherited autoinflammatory disease. It is also noteworthy that even when a cytoplasmic innate immune sensor has a direct ligand, such as bacterial peptidoglycan (NOD1 or NOD2), RNA (RIG-I or MDA5), or DNA (cGAS or IFI16), it can still be influenced by posttranslational modification to dramatically alter its response. Therefore, due to their existence in the cytoplasmic milieu, posttranslational modification is a key determinant of intracellular innate immune receptor functionality.
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Affiliation(s)
- Paul J. Baker
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Dominic De Nardo
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Fiona Moghaddas
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Le Son Tran
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Annabell Bachem
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Tan Nguyen
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Thomas Hayman
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Hazel Tye
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - James E. Vince
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Sammy Bedoui
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Richard L. Ferrero
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Seth L. Masters
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
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Chunfa L, Xin S, Qiang L, Sreevatsan S, Yang L, Zhao D, Zhou X. The Central Role of IFI204 in IFN-β Release and Autophagy Activation during Mycobacterium bovis Infection. Front Cell Infect Microbiol 2017; 7:169. [PMID: 28529930 PMCID: PMC5418236 DOI: 10.3389/fcimb.2017.00169] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 04/18/2017] [Indexed: 01/16/2023] Open
Abstract
Mycobacterium bovis (M. bovis) is the pathogen of animals and humans that can replicate in the phagosomes of myeloid cells. Cytosolic detection of bacterial products plays a crucial role in initiating the innate immune response, including autophagy activation and interferon-β (IFN-β) release. Although IFN-β release and autophagy activation have been reported during mycobacterium infection, the mechanisms underlying remains poorly defined. Here, we demonstrated that IFN-β release increases in macrophages exposed to M. bovis and this requires the activation of the DNA sensor of interferon-γ inducible protein 204 (IFI204). Knockdown of the IFI204 in immortalized and primary murine macrophages blocked IFN-β production and autophagy marker LC3 expression. Thus, our results indicate that the IFI204 is an important sensor for innate immune responses of M. bovis infection.
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Affiliation(s)
- Liu Chunfa
- State Key Laboratories for Agrobiotechnology, Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural UniversityBeijing, China
| | - Sun Xin
- State Key Laboratories for Agrobiotechnology, Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural UniversityBeijing, China
| | - Li Qiang
- Department of Veterinary Medicine, College of Agriculture, Ningxia UniversityYinchuan, China
| | - Srinand Sreevatsan
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of MinnesotaSaint Paul, MN, USA
| | - Lifeng Yang
- State Key Laboratories for Agrobiotechnology, Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural UniversityBeijing, China
| | - Deming Zhao
- State Key Laboratories for Agrobiotechnology, Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural UniversityBeijing, China
| | - Xiangmei Zhou
- State Key Laboratories for Agrobiotechnology, Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural UniversityBeijing, China
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79
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Torii Y, Kawada JI, Murata T, Yoshiyama H, Kimura H, Ito Y. Epstein-Barr virus infection-induced inflammasome activation in human monocytes. PLoS One 2017; 12:e0175053. [PMID: 28369146 PMCID: PMC5378412 DOI: 10.1371/journal.pone.0175053] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/20/2017] [Indexed: 01/15/2023] Open
Abstract
Inflammasomes are cytoplasmic sensors that regulate the activity of caspase-1 and the secretion of interleukin-1β (IL-1β) or interleukin-18 (IL-18) in response to foreign molecules, including viral pathogens. They are considered to be an important link between the innate and adaptive immune responses. However, the mechanism by which inflammasome activation occurs during primary Epstein-Barr virus (EBV) infection remains unknown. Human B lymphocytes and epithelial cells are major targets of EBV, although it can also infect a variety of other cell types. In this study, we found that EBV could infect primary human monocytes and the monocyte cell line, THP-1, inducing inflammasome activation. We incubated cell-free EBV with THP-1 cells or primary human monocytes, then confirmed EBV infection using confocal microscopy and flow cytometry. Lytic and latent EBV genes were detected by real-time RT-PCR in EBV-infected monocytes. EBV infection of THP-1 cells and primary human monocytes induced caspase-dependent IL-1β production, while EBV infection of B-cell or T-cell lines did not induce IL-1β production. To identify the sensor molecule responsible for inflammasome activation during EBV infection, we examined the mRNA and the protein levels of NLR family pyrin domain-containing 3 (NLRP3), absent in melanoma 2 (AIM2), and interferon-inducible protein 16 (IFI16). Increased AIM2 levels were observed in EBV-infected THP-1 cells and primary human monocytes, whereas levels of IFI16 and NLRP3 did not show remarkable change. Furthermore, knockdown of AIM2 by small interfering RNA attenuated caspase-1 activation. Taken together, our results suggest that EBV infection of human monocytes induces caspase-1-dependent IL-1β production, and that AIM2, acting as an inflammasome, is involved in this response.
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Affiliation(s)
- Yuka Torii
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Department of Virology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Jun-ichi Kawada
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
- * E-mail:
| | - Takayuki Murata
- Department of Virology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hironori Yoshiyama
- Department of Microbiology, Shimane University Faculty of Medicine, Izumo, Shimane
| | - Hiroshi Kimura
- Department of Virology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yoshinori Ito
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
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80
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Mariggiò G, Koch S, Zhang G, Weidner-Glunde M, Rückert J, Kati S, Santag S, Schulz TF. Kaposi Sarcoma Herpesvirus (KSHV) Latency-Associated Nuclear Antigen (LANA) recruits components of the MRN (Mre11-Rad50-NBS1) repair complex to modulate an innate immune signaling pathway and viral latency. PLoS Pathog 2017; 13:e1006335. [PMID: 28430817 PMCID: PMC5415203 DOI: 10.1371/journal.ppat.1006335] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 05/03/2017] [Accepted: 04/05/2017] [Indexed: 12/31/2022] Open
Abstract
Kaposi Sarcoma Herpesvirus (KSHV), a γ2-herpesvirus and class 1 carcinogen, is responsible for at least three human malignancies: Kaposi Sarcoma (KS), Primary Effusion Lymphoma (PEL) and Multicentric Castleman's Disease (MCD). Its major nuclear latency protein, LANA, is indispensable for the maintenance and replication of latent viral DNA in infected cells. Although LANA is mainly a nuclear protein, cytoplasmic isoforms of LANA exist and can act as antagonists of the cytoplasmic DNA sensor, cGAS. Here, we show that cytosolic LANA also recruits members of the MRN (Mre11-Rad50-NBS1) repair complex in the cytosol and thereby inhibits their recently reported role in the sensing of cytoplasmic DNA and activation of the NF-κB pathway. Inhibition of NF-κB activation by cytoplasmic LANA is accompanied by increased lytic replication in KSHV-infected cells, suggesting that MRN-dependent NF-κB activation contributes to KSHV latency. Cytoplasmic LANA may therefore support the activation of KSHV lytic replication in part by counteracting the activation of NF-κB in response to cytoplasmic DNA. This would complement the recently described role of cytoplasmic LANA in blocking an interferon response triggered by cGAS and thereby promoting lytic reactivation. Our findings highlight a second point at which cytoplasmic LANA interferes with the innate immune response, as well as the importance of the recently discovered role of cytoplasmic MRN complex members as innate sensors of cytoplasmic DNA for the control of KSHV replication.
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MESH Headings
- Acid Anhydride Hydrolases
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Antigens, Viral/metabolism
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cytoplasm/metabolism
- DNA Repair Enzymes/genetics
- DNA Repair Enzymes/metabolism
- DNA Replication
- DNA, Viral/genetics
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- HEK293 Cells
- Herpesvirus 8, Human/genetics
- Herpesvirus 8, Human/immunology
- Herpesvirus 8, Human/physiology
- Humans
- Immunity, Innate
- MRE11 Homologue Protein
- Models, Biological
- NF-kappa B/genetics
- NF-kappa B/metabolism
- Nuclear Proteins/genetics
- Nuclear Proteins/immunology
- Nuclear Proteins/metabolism
- Protein Isoforms
- Sarcoma, Kaposi/immunology
- Sarcoma, Kaposi/virology
- Signal Transduction
- Virus Latency
- Virus Replication
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Affiliation(s)
- Giuseppe Mariggiò
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Sandra Koch
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Guigen Zhang
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Magdalena Weidner-Glunde
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Jessica Rückert
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Semra Kati
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Susann Santag
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Thomas F. Schulz
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
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81
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Cai K, Wang B, Dou H, Luan R, Bao X, Chu J. IL-17A promotes the proliferation of human nasopharyngeal carcinoma cells through p300-mediated Akt1 acetylation. Oncol Lett 2017; 13:4238-4244. [PMID: 28588706 PMCID: PMC5452892 DOI: 10.3892/ol.2017.5962] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 02/07/2017] [Indexed: 12/12/2022] Open
Abstract
Interleukin (IL)-17A is a T helper (Th)17 cell-secreted cytokine that is able to induce various inflammatory responses. There is emerging evidence that IL-17A is generated in the cancer microenvironment of human nasopharyngeal carcinoma (NPC). However, the role of IL-17A in NPC remains unclear. Thus, the present study aimed to examine the direct influence of IL-17A stimulation on the proliferation of human NPC cells and identify the underlying molecular mechanisms. Furthermore, E1A binding protein p300 (p300)-mediated AKT serine/threonine kinase 1 (Akt1) acetylation and its role in regulating the proliferation of NPC cells was investigated. The results of the current study demonstrated that IL-17A stimulation in vitro increased the proliferation of human NPC cells. Furthermore, Akt1 acetylation was identified to be enhanced in human NPC cells induced by IL-17A. Additionally, p300 induction was demonstrated to be required for Akt1 acetylation in human NPC cells following exposure to IL-17A. Functionally, p300-mediated Akt1 acetylation contributed to the proliferation of human NPC cells stimulated by IL-17A. In conclusion, the results of the present demonstrate a novel activity of IL-17A that promotes human NPC cell proliferation via p300-mediated Akt1 acetylation. This may provide a potential strategy for the treatment of patients with NPC through the inhibition of IL-17A or its receptors.
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Affiliation(s)
- Kemin Cai
- Department of Otorhinolaryngology Head and Neck Surgery, Taizhou People's Hospital, Taizhou, Jiangsu 225300, P.R. China
| | - Bing Wang
- Department of Neurosurgery, Suzhou Kowloon Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, Suzhou, Jiangsu 215021, P.R. China
| | - Hongmei Dou
- Department of Otorhinolaryngology Head and Neck Surgery, Taizhou People's Hospital, Taizhou, Jiangsu 225300, P.R. China
| | - Ronglan Luan
- Department of Otorhinolaryngology Head and Neck Surgery, Taizhou People's Hospital, Taizhou, Jiangsu 225300, P.R. China
| | - Xueli Bao
- Department of Otorhinolaryngology Head and Neck Surgery, Taizhou People's Hospital, Taizhou, Jiangsu 225300, P.R. China
| | - Jiusheng Chu
- Department of Otorhinolaryngology Head and Neck Surgery, Taizhou People's Hospital, Taizhou, Jiangsu 225300, P.R. China
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82
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Abstract
The female reproductive tract (FRT) is a major site for human immunodeficiency virus (HIV) infection. There currently exists a poor understanding of how the innate immune system is activated upon HIV transmission and how this activation may affect systemic spread of HIV from the FRT. However, multiple mechanisms for how HIV is sensed have been deciphered using model systems with cell lines and peripheral blood-derived cells. The aim of this review is to summarize recent progress in the field of HIV innate immune sensing and place this in the context of the FRT. Because HIV is somewhat unique as an STD that thrives under inflammatory conditions, the response of cells upon sensing HIV gene products can either promote or limit HIV infection depending on the context. Future studies should include investigations into how FRT-derived primary cells sense and respond to HIV to confirm conclusions drawn from non-mucosal cells. Understanding how cells of the FRT participate in and effect innate immune sensing of HIV will provide a clearer picture of what parameters during the early stages of HIV exposure determine transmission success. Such knowledge could pave the way for novel approaches for preventing HIV acquisition in women.
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83
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Lee HR, Choi UY, Hwang SW, Kim S, Jung JU. Viral Inhibition of PRR-Mediated Innate Immune Response: Learning from KSHV Evasion Strategies. Mol Cells 2016; 39:777-782. [PMID: 27871174 PMCID: PMC5125932 DOI: 10.14348/molcells.2016.0232] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/04/2016] [Accepted: 11/07/2016] [Indexed: 12/18/2022] Open
Abstract
The innate immune system has evolved to detect and destroy invading pathogens before they can establish systemic infection. To successfully eradicate pathogens, including viruses, host innate immunity is activated through diverse pattern recognition receptors (PRRs) which detect conserved viral signatures and trigger the production of type I interferon (IFN) and pro-inflammatory cytokines to mediate viral clearance. Viral persistence requires that viruses co-opt cellular pathways and activities for their benefit. In particular, due to the potent antiviral activities of IFN and cytokines, viruses have developed various strategies to meticulously modulate intracellular innate immune sensing mechanisms to facilitate efficient viral replication and persistence. In this review, we highlight recent advances in the study of viral immune evasion strategies with a specific focus on how Kaposi's sarcoma-associated herpesvirus (KSHV) effectively targets host PRR signaling pathways.
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Affiliation(s)
- Hye-Ra Lee
- Department of Biotechnology and Bioinformatics, College of Science and Technology, Korea University, Sejong 30019,
Korea
| | - Un Yung Choi
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Harlyne J. Norris Cancer Research Tower, 1450 Biggy Street, Los Angeles, California 90033,
USA
| | - Sung-Woo Hwang
- Department of Biotechnology and Bioinformatics, College of Science and Technology, Korea University, Sejong 30019,
Korea
| | - Stephanie Kim
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Harlyne J. Norris Cancer Research Tower, 1450 Biggy Street, Los Angeles, California 90033,
USA
| | - Jae U. Jung
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Harlyne J. Norris Cancer Research Tower, 1450 Biggy Street, Los Angeles, California 90033,
USA
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84
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Fan YH, Roy S, Mukhopadhyay R, Kapoor A, Duggal P, Wojcik GL, Pass RF, Arav-Boger R. Role of nucleotide-binding oligomerization domain 1 (NOD1) and its variants in human cytomegalovirus control in vitro and in vivo. Proc Natl Acad Sci U S A 2016; 113:E7818-E7827. [PMID: 27856764 PMCID: PMC5137695 DOI: 10.1073/pnas.1611711113] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Induction of nucleotide-binding oligomerization domain 2 (NOD2) and downstream receptor-interacting serine/threonine-protein kinase 2 (RIPK2) by human cytomegalovirus (HCMV) is known to up-regulate antiviral responses and suppress virus replication. We investigated the role of nucleotide-binding oligomerization domain 1 (NOD1), which also signals through RIPK2, in HCMV control. NOD1 activation by Tri-DAP (NOD1 agonist) suppressed HCMV and induced IFN-β. Mouse CMV was also inhibited through NOD1 activation. NOD1 knockdown (KD) or inhibition of its activity with small molecule ML130 enhanced HCMV replication in vitro. NOD1 mutations displayed differential effects on HCMV replication and antiviral responses. In cells overexpressing the E56K mutation in the caspase activation and recruitment domain, virus replication was enhanced, but in cells overexpressing the E266K mutation in the nucleotide-binding domain or the wild-type NOD1, HCMV was inhibited, changes that correlated with IFN-β expression. The interaction of NOD1 and RIPK2 determined the outcome of virus replication, as evidenced by enhanced virus growth in NOD1 E56K mutant cells (which failed to interact with RIPK2). NOD1 activities were executed through IFN-β, given that IFN-β KD reduced the inhibitory effect of Tri-DAP on HCMV. Signaling through NOD1 resulting in HCMV suppression was IKKα-dependent and correlated with nuclear translocation and phosphorylation of IRF3. Finally, NOD1 polymorphisms were significantly associated with the risk of HCMV infection in women who were infected with HCMV during participation in a glycoprotein B vaccine trial. Collectively, our data indicate a role for NOD1 in HCMV control via RIPK2- IKKα-IRF3 and suggest that its polymorphisms predict the risk of infection.
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Affiliation(s)
- Yi-Hsin Fan
- Division of Infectious Diseases, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287
| | - Sujayita Roy
- Division of Infectious Diseases, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287
| | - Rupkatha Mukhopadhyay
- Division of Infectious Diseases, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287
| | - Arun Kapoor
- Division of Infectious Diseases, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287
| | - Priya Duggal
- Department of Genetic Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21231
| | - Genevieve L Wojcik
- Department of Genetic Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21231
| | - Robert F Pass
- Division of Infectious Diseases, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Ravit Arav-Boger
- Division of Infectious Diseases, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287;
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85
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Chiang C, Gack MU. Post-translational Control of Intracellular Pathogen Sensing Pathways. Trends Immunol 2016; 38:39-52. [PMID: 27863906 PMCID: PMC5580928 DOI: 10.1016/j.it.2016.10.008] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 01/15/2023]
Abstract
Mammalian cells recognize virus-derived nucleic acids using a defined set of intracellular sensors including the DNA sensors cyclic GMP–AMP (cGAMP) synthase (cGAS) and interferon gamma (IFNγ)-inducible protein 16 (IFI16) as well as viral RNA receptors of the retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) family. Following innate immune recognition, these sensors launch an immune response that is characterized by the transcriptional upregulation of many antiviral molecules, including proinflammatory cytokines, chemokines, and IFN-stimulated genes. Recent studies have demonstrated that the signal transduction initiated by these sensors is sophisticatedly regulated by post-translational modifications (PTMs) resulting in a robust yet ‘tunable’ cytokine response to maintain immune homeostasis. Here we summarize recent advances in our understanding of how PTMs and regulatory enzymes control the signaling activity of RLRs, cGAS, and IFI16 as well as their proximal adaptor proteins. Positive feedforward regulatory mechanisms serve as an important means of signal amplification to ensure an effective innate immune response. However, negative regulatory circuits are essential for the prevention of premature or overactive proinflammatory responses, which could have harmful consequences for the host organism. Phosphorylation and different types of polyubiquitin chains, particularly K63-linked ubiquitination, are important for fine-tuning signaling initiated by intracellular viral RNA and DNA receptors. Acetylation, glutamylation, and deamidation of innate immune sensors or components in their signaling pathways also dynamically modulate antiviral cytokine induction. Insight into the molecular mechanisms and regulatory enzymes that modulate innate sensing pathways may lead to therapeutics to boost antiviral immunity or dampen proinflammatory/autoimmune responses.
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Affiliation(s)
- Cindy Chiang
- Department of Microbiology, The University of Chicago, Chicago, IL 60637, USA
| | - Michaela U Gack
- Department of Microbiology, The University of Chicago, Chicago, IL 60637, USA.
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Kumar B, Chandran B. KSHV Entry and Trafficking in Target Cells-Hijacking of Cell Signal Pathways, Actin and Membrane Dynamics. Viruses 2016; 8:v8110305. [PMID: 27854239 PMCID: PMC5127019 DOI: 10.3390/v8110305] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/24/2016] [Accepted: 11/03/2016] [Indexed: 01/27/2023] Open
Abstract
Kaposi's sarcoma associated herpesvirus (KSHV) is etiologically associated with human endothelial cell hyperplastic Kaposi's sarcoma and B-cell primary effusion lymphoma. KSHV infection of adherent endothelial and fibroblast cells are used as in vitro models for infection and KSHV enters these cells by host membrane bleb and actin mediated macropinocytosis or clathrin endocytosis pathways, respectively. Infection in endothelial and fibroblast cells is initiated by the interactions between multiple viral envelope glycoproteins and cell surface associated heparan sulfate (HS), integrins (α3β1, αVβ3 and αVβ5), and EphA2 receptor tyrosine kinase (EphA2R). This review summarizes the accumulated studies demonstrating that KSHV manipulates the host signal pathways to enter and traffic in the cytoplasm of the target cells, to deliver the viral genome into the nucleus, and initiate viral gene expression. KSHV interactions with the cell surface receptors is the key platform for the manipulations of host signal pathways which results in the simultaneous induction of FAK, Src, PI3-K, Rho-GTPase, ROS, Dia-2, PKC ζ, c-Cbl, CIB1, Crk, p130Cas and GEF-C3G signal and adaptor molecules that play critical roles in the modulation of membrane and actin dynamics, and in the various steps of the early stages of infection such as entry and trafficking towards the nucleus. The Endosomal Sorting Complexes Required for Transport (ESCRT) proteins are also recruited to assist in viral entry and trafficking. In addition, KSHV interactions with the cell surface receptors also induces the host transcription factors NF-κB, ERK1/2, and Nrf2 early during infection to initiate and modulate viral and host gene expression. Nuclear delivery of the viral dsDNA genome is immediately followed by the host innate responses such as the DNA damage response (DDR), inflammasome and interferon responses. Overall, these studies form the initial framework for further studies of simultaneous targeting of KSHV glycoproteins, host receptor, signal molecules and trafficking machinery that would lead into novel therapeutic methods to prevent KSHV infection of target cells and consequently the associated malignancies.
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Affiliation(s)
- Binod Kumar
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA.
| | - Bala Chandran
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA.
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Abstract
Upon virus infection, host cells mount a concerted innate immune response involving type I interferon and pro-inflammatory cytokines to enable elimination of the pathogen. Recently, cGAS and STING have been identified as intracellular sensors that activate the interferon pathway in response to virus infection and thus mediate host defense against a range of DNA and RNA viruses. Here we review how viruses are sensed by the cGAS-STING signaling pathway as well as how viruses modulate this pathway. Mechanisms utilized by viral proteins to inhibit cGAS and/or STING are also discussed. On the flip side, host cells have also evolved strategies to thwart viral immune escape. The balance between host immune control and viral immune evasion is pivotal to viral pathogenesis, and we discuss this virus-host stand-off in the context of the cGAS-STING innate immune pathway.
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Affiliation(s)
- Zhe Ma
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Blossom Damania
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Kumar B, Dutta D, Iqbal J, Ansari MA, Roy A, Chikoti L, Pisano G, Veettil MV, Chandran B. ESCRT-I Protein Tsg101 Plays a Role in the Post-macropinocytic Trafficking and Infection of Endothelial Cells by Kaposi's Sarcoma-Associated Herpesvirus. PLoS Pathog 2016; 12:e1005960. [PMID: 27764233 PMCID: PMC5072609 DOI: 10.1371/journal.ppat.1005960] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 09/28/2016] [Indexed: 11/19/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) binding to the endothelial cell surface heparan sulfate is followed by sequential interactions with α3β1, αVβ3 and αVβ5 integrins and Ephrin A2 receptor tyrosine kinase (EphA2R). These interactions activate host cell pre-existing FAK, Src, PI3-K and RhoGTPase signaling cascades, c-Cbl mediated ubiquitination of receptors, recruitment of CIB1, p130Cas and Crk adaptor molecules, and membrane bleb formation leading to lipid raft dependent macropinocytosis of KSHV into human microvascular dermal endothelial (HMVEC-d) cells. The Endosomal Sorting Complexes Required for Transport (ESCRT) proteins, ESCRT-0, -I, -II, and-III, play a central role in clathrin-mediated internalized ubiquitinated receptor endosomal trafficking and sorting. ESCRT proteins have also been shown to play roles in viral egress. We have recently shown that ESCRT-0 component Hrs protein associates with the plasma membrane during macropinocytosis and mediates KSHV entry via ROCK1 mediated phosphorylation of NHE1 and local membrane pH change. Here, we demonstrate that the ESCRT-I complex Tsg101 protein also participates in the macropinocytosis of KSHV and plays a role in KSHV trafficking. Knockdown of Tsg101 did not affect virus entry in HMVEC-d and human umbilical vein endothelial (HUVEC) cells but significantly inhibited the KSHV genome entry into the nucleus and consequently viral gene expression in these cells. Double and triple immunofluorescence, proximity ligation immunofluorescence and co-immuoprecipitation studies revealed the association of Tsg101 with the KSHV containing macropinosomes, and increased levels of Tsg101 association/interactions with EphA2R, c-Cbl, p130Cas and Crk signal molecules, as well as with upstream and downstream ESCRT components such as Hrs (ESCRT-0), EAP45 (ESCRT-II), CHMP6 (ESCRT-III) and CHMP5 (ESCRT-III) in the KSHV infected cells. Tsg101 was also associated with early (Rab5) and late endosomal (Rab7) stages of KSHV intracellular trafficking, and CHMP5 (ESCRT-III) was also associated with Rab 5 and Rab 7. Knockdown of Tsg101 significantly inhibited the transition of virus from early to late endosomes. Collectively, our studies reveal that Tsg101 plays a role in the trafficking of macropinocytosed KSHV in the endothelial cells which is essential for the successful viral genome delivery into the nucleus, viral gene expression and infection. Thus, ESCRT molecules could serve as therapeutic targets to combat KSHV infection.
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Affiliation(s)
- Binod Kumar
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, United States Of America
| | - Dipanjan Dutta
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, United States Of America
| | - Jawed Iqbal
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, United States Of America
| | - Mairaj Ahmed Ansari
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, United States Of America
| | - Arunava Roy
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, United States Of America
| | - Leela Chikoti
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, United States Of America
| | - Gina Pisano
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, United States Of America
| | - Mohanan Valiya Veettil
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, United States Of America
| | - Bala Chandran
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, United States Of America
- * E-mail:
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89
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Iqbal J, Ansari MA, Kumar B, Dutta D, Roy A, Chikoti L, Pisano G, Dutta S, Vahedi S, Veettil MV, Chandran B. Histone H2B-IFI16 Recognition of Nuclear Herpesviral Genome Induces Cytoplasmic Interferon-β Responses. PLoS Pathog 2016; 12:e1005967. [PMID: 27764250 PMCID: PMC5072618 DOI: 10.1371/journal.ppat.1005967] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Accepted: 09/30/2016] [Indexed: 11/25/2022] Open
Abstract
IFI16 (gamma-interferon-inducible protein 16), a predominantly nuclear protein involved in transcriptional regulation, also functions as an innate immune response DNA sensor and induces the IL-1β and antiviral type-1 interferon-β (IFN-β) cytokines. We have shown that IFI16, in association with BRCA1, functions as a sequence independent nuclear sensor of episomal dsDNA genomes of KSHV, EBV and HSV-1. Recognition of these herpesvirus genomes resulted in IFI16 acetylation, BRCA1-IFI16-ASC-procaspase-1 inflammasome formation, cytoplasmic translocation, and IL-1β generation. Acetylated IFI16 also interacted with cytoplasmic STING and induced IFN-β. However, the identity of IFI16 associated nuclear proteins involved in STING activation and the mechanism is not known. Mass spectrometry of proteins precipitated by anti-IFI16 antibodies from uninfected endothelial cell nuclear lysate revealed that histone H2B interacts with IFI16. Single and double proximity ligation microscopy, immunoprecipitation, EdU-genome labeled virus infection, and chromatin immunoprecipitation studies demonstrated that H2B is associated with IFI16 and BRCA1 in the nucleus in physiological conditions. De novo KSHV and HSV-1 infection as well as latent KSHV and EBV infection induces the cytoplasmic distribution of H2B-IFI16, H2B-BRCA1 and IFI16-ASC complexes. Vaccinia virus (dsDNA) cytoplasmic replication didn’t induce the redistribution of nuclear H2B-IFI16 or H2B into the cytoplasm. H2B is critical in KSHV and HSV-1 genome recognition by IFI16 during de novo infection. Viral genome sensing by IFI16-H2B-BRCA1 leads to BRCA1 dependent recruitment of p300, and acetylation of H2B and IFI16. BRCA1 knockdown or inhibition of p300 abrogated the acetylation of H2B-IFI16 or H2B. Ran-GTP protein mediated the translocation of acetylated H2B and IFI16 to the cytoplasm along with BRCA1 that is independent of IFI16-ASC inflammasome. ASC knockdown didn’t affect the acetylation of H2B, its cytoplasmic transportation, and the association of STING with IFI16 and H2B during KSHV infection. Absence of H2B didn’t affect IFI16-ASC association and cytoplasmic distribution and thus demonstrating that IFI16-H2B complex is independent of IFI16-ASC-procaspase-1-inflammasome complex formed during infection. The H2B-IFI16-BRCA1 complex interacted with cGAS and STING in the cytoplasm leading to TBK1 and IRF3 phosphorylation, nuclear translocation of pIRF3 and IFN-β production. Silencing of H2B, cGAS and STING inhibited IFN-β induction but not IL-1β secretion, and cGAMP activity is significantly reduced by H2B and IFI16 knockdown during infection. Silencing of ASC inhibited IL-1β secretion but not IFN-β secretion during de novo KSHV and HSV-1 infection. These studies identify H2B as an innate nuclear sensor mediating a novel extra chromosomal function, and reveal that two IFI16 complexes mediate KSHV and HSV-1 genome recognition responses, with recognition by the IFI16-BRCA1-H2B complex resulting in IFN-β responses and recognition by IFI16-BRCA1 resulting in inflammasome responses. Eukaryotic cells elicit innate immune responses against invading microbes including viruses. IFI16, a predominantly nuclear protein, has emerged as an innate response nuclear DNA sensor. Recognition of nuclear KSHV, HSV-1 and EBV dsDNA genomes by IFI16-BRCA1 leads to IFI16 acetylation, cytoplasmic translocation of the BRCA1-IFI16-ASC-procaspase-1 inflammasome complex and IL-1β generation. Here, we demonstrate that histone H2B is associated with IFI16-BRCA1 in the nucleus under physiological conditions. Recognition of nuclear viral genomes by IFI16-H2B-BRCA1 leads to BRCA1-p300 mediated acetylation of H2B and IFI16, and cytoplasmic transport of H2B-IFI16-BRCA1 via Ran GTP protein. The inflammasome independent cytoplasmic IFI16-H2B-BRCA1 complex interacts with cGAS and STING resulting in TBK1 and IRF3 phosphorylation, and nuclear pIRF3-mediated IFN-β induction. H2B knockdown inhibits IFN-β production while ASC silencing doesn’t affect IFN-β induction. Our studies identify H2B as an innate nuclear sensor and reveal that two IFI16 complexes mediate nuclear herpesviral genome recognition responses, IFI16-BRCA1-H2B-IFN-β responses and IFI16-BRCA1-inflammasome responses.
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Affiliation(s)
- Jawed Iqbal
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Mairaj Ahmed Ansari
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Binod Kumar
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Dipanjan Dutta
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Arunava Roy
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Leela Chikoti
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Gina Pisano
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Sujoy Dutta
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Shahrooz Vahedi
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Mohanan Valiya Veettil
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Bala Chandran
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
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90
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Nuclear Innate Immune DNA Sensor IFI16 Is Degraded during Lytic Reactivation of Kaposi's Sarcoma-Associated Herpesvirus (KSHV): Role of IFI16 in Maintenance of KSHV Latency. J Virol 2016; 90:8822-41. [PMID: 27466416 PMCID: PMC5021400 DOI: 10.1128/jvi.01003-16] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 07/13/2016] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED IFI16 (interferon gamma-inducible protein 16) recognizes nuclear episomal herpesvirus (Kaposi's sarcoma-associated herpesvirus [KSHV], Epstein-Barr virus [EBV], and herpes simplex virus 1 [HSV-1]) genomes and induces the inflammasome and interferon beta responses. It also acts as a lytic replication restriction factor and inhibits viral DNA replication (human cytomegalovirus [HCMV] and human papillomavirus [HPV]) and transcription (HSV-1, HCMV, and HPV) through epigenetic modifications of the viral genomes. To date, the role of IFI16 in the biology of latent viruses is not known. Here, we demonstrate that knockdown of IFI16 in the latently KSHV-infected B-lymphoma BCBL-1 and BC-3 cell lines results in lytic reactivation and increases in levels of KSHV lytic transcripts, proteins, and viral genome replication. Similar results were also observed during KSHV lytic cycle induction in TREX-BCBL-1 cells with the doxycycline-inducible lytic cycle switch replication and transcription activator (RTA) gene. Overexpression of IFI16 reduced lytic gene induction by the chemical agent 12-O-tetradecoylphorbol-13-acetate (TPA). IFI16 protein levels were significantly reduced or absent in TPA- or doxycycline-induced cells expressing lytic KSHV proteins. IFI16 is polyubiquitinated and degraded via the proteasomal pathway. The degradation of IFI16 was absent in phosphonoacetic acid-treated cells, which blocks KSHV DNA replication and, consequently, late lytic gene expression. Chromatin immunoprecipitation assays of BCBL-1 and BC-3 cells demonstrated that IFI16 binds to KSHV gene promoters. Uninfected epithelial SLK and osteosarcoma U2OS cells transfected with KSHV luciferase promoter constructs confirmed that IFI16 functions as a transcriptional repressor. These results reveal that KSHV utilizes the innate immune nuclear DNA sensor IFI16 to maintain its latency and repression of lytic transcripts, and a late lytic KSHV gene product(s) targets IFI16 for degradation during lytic reactivation. IMPORTANCE Like all herpesviruses, latency is an integral part of the life cycle of Kaposi's sarcoma-associated herpesvirus (KSHV), an etiological agent for many human cancers. Herpesviruses utilize viral and host factors to successfully evade the host immune system to maintain latency. Reactivation is a complex event where the latent episomal viral genome springs back to active transcription of lytic cycle genes. Our studies reveal that KSHV has evolved to utilize the innate immune sensor IFI16 to keep lytic cycle transcription in dormancy. We demonstrate that IFI16 binds to the lytic gene promoter, acts as a transcriptional repressor, and thereby helps to maintain latency. We also discovered that during the late stage of lytic replication, KSHV selectively degrades IFI16, thus relieving transcriptional repression. This is the first report to demonstrate the role of IFI16 in latency maintenance of a herpesvirus, and further understanding will lead to the development of strategies to eliminate latent infection.
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91
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Lupfer C, Anand PK. Integrating Inflammasome Signaling in Sexually Transmitted Infections. Trends Immunol 2016; 37:703-714. [PMID: 27592079 PMCID: PMC5086000 DOI: 10.1016/j.it.2016.08.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 08/03/2016] [Accepted: 08/05/2016] [Indexed: 02/07/2023]
Abstract
Inflammasomes are cytosolic multiprotein platforms with pivotal roles in infectious diseases. Activation of inflammasomes results in proinflammatory cytokine signaling and pyroptosis. Sexually transmitted infections (STIs) are a major health problem worldwide, yet few studies have probed the impact of inflammasome signaling during these infections. Due to the dearth of appropriate infection models, our current understanding of inflammasomes in STIs is mostly drawn from results obtained in vitro, from distant infection sites, or from related microbial strains that are not sexually transmitted. Understanding how inflammasomes influence the outcome of STIs may lead to the development of novel and effective strategies to control disease and prevent transmission. Here we discuss and highlight the recent progress in this field.
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Affiliation(s)
- Christopher Lupfer
- Department of Biology, Missouri State University, Springfield, MO 65809, USA
| | - Paras K Anand
- Infectious Diseases and Immunity, Imperial College London, London W12 0NN, UK.
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92
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Regulatory Interaction between the Cellular Restriction Factor IFI16 and Viral pp65 (pUL83) Modulates Viral Gene Expression and IFI16 Protein Stability. J Virol 2016; 90:8238-50. [PMID: 27384655 DOI: 10.1128/jvi.00923-16] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 06/28/2016] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED A key player in the intrinsic resistance against human cytomegalovirus (HCMV) is the interferon-γ-inducible protein 16 (IFI16), which behaves as a viral DNA sensor in the first hours postinfection and as a repressor of viral gene transcription in the later stages. Previous studies on HCMV replication demonstrated that IFI16 binds to the viral protein kinase pUL97, undergoes phosphorylation, and relocalizes to the cytoplasm of infected cells. In this study, we demonstrate that the tegument protein pp65 (pUL83) recruits IFI16 to the promoter of the UL54 gene and downregulates viral replication, as shown by use of the HCMV mutant v65Stop, which lacks pp65 expression. Interestingly, at late time points of HCMV infection, IFI16 is stabilized by its interaction with pp65, which stood in contrast to IFI16 degradation, observed in herpes simplex virus 1 (HSV-1)-infected cells. Moreover, we found that its translocation to the cytoplasm, in addition to pUL97, strictly depends on pp65, as demonstrated with the HCMV mutant RV-VM1, which expresses a form of pp65 unable to translocate into the cytoplasm. Thus, these data reveal a dual role for pp65: during early infection, it modulates IFI16 activity at the promoter of immediate-early and early genes; subsequently, it delocalizes IFI16 from the nucleus into the cytoplasm, thereby stabilizing and protecting it from degradation. Overall, these data identify a novel activity of the pp65/IFI16 interactome involved in the regulation of UL54 gene expression and IFI16 stability during early and late phases of HCMV replication. IMPORTANCE The DNA sensor IFI16, a member of the PYHIN proteins, restricts HCMV replication by impairing viral DNA synthesis. Using a mutant virus lacking the tegument protein pp65 (v65Stop), we demonstrate that pp65 recruits IFI16 to the early UL54 gene promoter. As a putative counteraction to its restriction activity, pp65 supports the nucleocytoplasmic export of IFI16, which was demonstrated with the viral mutant RV-VM1 expressing a nuclearly retained pp65. These data reveal a dual role of pp65 in IFI16 regulation: in the early phase of HCMV infection, it contributes to viral evasion from IFI16 restriction activity, while at later time points, it promotes the nuclear delocalization of IFI16, thereby stabilizing and protecting it from degradation. In the present work, we further clarify the mechanisms HCMV relies on to overcome intracellular innate immune restriction and provide new insights into the relevance of DNA-sensing restriction factor IFI16 during HCMV infection.
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93
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The expanding regulatory network of STING-mediated signaling. Curr Opin Microbiol 2016; 32:144-150. [PMID: 27414485 PMCID: PMC4983512 DOI: 10.1016/j.mib.2016.05.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 05/20/2016] [Indexed: 01/07/2023]
Abstract
The identification and characterization of DNA-sensing pathways has been a subject of intensive investigation for the last decade. This interest, in part, is supported by the fact that the main outcome of DNA-responses is production of type I interferon (IFN-I), which, if produced in excessive amounts, leads to various pathologies. STING (stimulator of interferon genes) is positioned in the center of these responses and is activated either via direct sensing of second messengers or via interaction with upstream sensors of dsDNA. STING mediates responses to pathogens as well as host-derived DNA and is, therefore, linked to various autoimmune diseases, cancer predisposition and ageing. Recent mouse models of DNA damage showed the adaptor STING to be crucial for heightened resting levels of IFN-I. In this review, we will focus on recent advances in understanding the regulation of STING-signaling and identification of its novel components.
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94
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Choubey D, Panchanathan R. IFI16, an amplifier of DNA-damage response: Role in cellular senescence and aging-associated inflammatory diseases. Ageing Res Rev 2016; 28:27-36. [PMID: 27063514 DOI: 10.1016/j.arr.2016.04.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 03/30/2016] [Accepted: 04/04/2016] [Indexed: 12/22/2022]
Abstract
DNA-damage induces a DNA-damage response (DDR) in mammalian cells. The response, depending upon the cell-type and the extent of DNA-damage, ultimately results in cell death or cellular senescence. DDR-induced signaling in cells activates the ATM-p53 and ATM-IKKα/β-interferon (IFN)-β signaling pathways, thus leading to an induction of the p53 and IFN-inducible IFI16 gene. Further, upon DNA-damage, DNA accumulates in the cytoplasm, thereby inducing the IFI16 protein and STING-dependent IFN-β production and activation of the IFI16 inflammasome, resulting in the production of proinflammatory cytokines (e.g., IL-1β and IL-18). Increased expression of IFI16 protein in a variety of cell-types promotes cellular senescence. However, reduced expression of IFI16 in cells promotes cell proliferation. Because expression of the IFI16 gene is induced by activation of DNA-damage response in cells and increased levels of IFI16 protein in cells potentiate the p53-mediated transcriptional activation of genes and p53 and pRb-mediated cell cycle arrest, we discuss how an improved understanding of the role of IFI16 protein in cellular senescence and associated inflammatory secretory phenotype is likely to identify the molecular mechanisms that contribute to the development of aging-associated human inflammatory diseases and a failure to cancer therapy.
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Affiliation(s)
- Divaker Choubey
- Cincinnati VA Medical Center, 3200 Vine Street, Cincinnati, OH 45220, United States; Department of Environmental Health, University of Cincinnati, 160 Panzeca Way, P.O. Box-670056, Cincinnati, OH 45267, United States.
| | - Ravichandran Panchanathan
- Cincinnati VA Medical Center, 3200 Vine Street, Cincinnati, OH 45220, United States; Department of Environmental Health, University of Cincinnati, 160 Panzeca Way, P.O. Box-670056, Cincinnati, OH 45267, United States
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95
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Liem J, Liu J. Stress Beyond Translation: Poxviruses and More. Viruses 2016; 8:v8060169. [PMID: 27314378 PMCID: PMC4926189 DOI: 10.3390/v8060169] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/24/2016] [Accepted: 06/08/2016] [Indexed: 02/06/2023] Open
Abstract
Poxviruses are large double-stranded DNA viruses that form viral factories in the cytoplasm of host cells. These viruses encode their own transcription machinery, but rely on host translation for protein synthesis. Thus, poxviruses have to cope with and, in most cases, reprogram host translation regulation. Granule structures, called antiviral granules (AVGs), have been observed surrounding poxvirus viral factories. AVG formation is associated with abortive poxvirus infection, and AVGs contain proteins that are typically found in stress granules (SGs). With certain mutant poxviruses lack of immunoregulatory factor(s), we can specifically examine the mechanisms that drive the formation of these structures. In fact, cytoplasmic macromolecular complexes form during many viral infections and contain sensing molecules that can help reprogram transcription. More importantly, the similarity between AVGs and cytoplasmic structures formed during RNA and DNA sensing events prompts us to reconsider the cause and consequence of these AVGs. In this review, we first summarize recent findings regarding how poxvirus manipulates host translation. Next, we compare and contrast SGs and AVGs. Finally, we review recent findings regarding RNA- and especially DNA-sensing bodies observed during viral infection.
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Affiliation(s)
- Jason Liem
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
| | - Jia Liu
- Department of Microbiology and Immunology, Center for Microbial Pathogenesis and Host Inflammatory Responses, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
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ESCRT-0 Component Hrs Promotes Macropinocytosis of Kaposi's Sarcoma-Associated Herpesvirus in Human Dermal Microvascular Endothelial Cells. J Virol 2016; 90:3860-3872. [PMID: 26819309 DOI: 10.1128/jvi.02704-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 01/21/2016] [Indexed: 01/03/2023] Open
Abstract
UNLABELLED Kaposi's sarcoma-associated herpesvirus (KSHV) enters human dermal microvascular endothelial cells (HMVEC-d), its naturalin vivotarget cells, by lipid raft-dependent macropinocytosis. The internalized viral envelope fuses with the macropinocytic membrane, and released capsid is transported to the nuclear vicinity, resulting in the nuclear entry of viral DNA. The endosomal sorting complexes required for transport (ESCRT) proteins, which include ESCRT-0, -I, -II, and -III, play a central role in endosomal trafficking and sorting of internalized and ubiquitinated receptors. Here, we examined the role of ESCRT-0 component Hrs (hepatocyte growth factor-regulated tyrosine kinase substrate) in KSHV entry into HMVEC-d by macropinocytosis. Knockdown of Hrs by short hairpin RNA (shRNA) transduction resulted in significant decreases in KSHV entry and viral gene expression. Immunofluorescence analysis (IFA) and plasma membrane isolation and proximity ligation assay (PLA) demonstrated the translocation of Hrs from the cytosol to the plasma membrane of infected cells and association with α-actinin-4. In addition, infection induced the plasma membrane translocation and activation of the serine/threonine kinase ROCK1, a downstream target of the RhoA GTPase. Hrs knockdown reduced these associations, suggesting that the recruitment of ROCK1 is an Hrs-mediated event. Interaction between Hrs and ROCK1 is essential for the ROCK1-induced phosphorylation of NHE1 (Na(+)/H(+)exchanger 1), which is involved in the regulation of intracellular pH. Thus, our studies demonstrate the plasma membrane association of ESCRT protein Hrs during macropinocytosis and suggest that KSHV entry requires both Hrs- and ROCK1-dependent mechanisms and that ROCK1-mediated phosphorylation of NHE1 and pH change is an essential event required for the macropinocytosis of KSHV. IMPORTANCE Macropinocytosis is the major entry pathway of KSHV in human dermal microvascular endothelial cells, the natural target cells of KSHV. Although the role of ESCRT protein Hrs has been extensively studied with respect to endosomal movement and sorting of ubiquitinated proteins into lysosomes, its function in macropinocytosis is not known. In the present study, we demonstrate for the first time that upon KSHV infection, the endogenous Hrs localizes to the plasma membrane and the membrane-associated Hrs facilitates assembly of signaling molecules, macropinocytosis, and virus entry. Hrs recruits ROCK1 to the membrane, which is required for the activation of NHE1 and an increase in submembranous intracellular pH occurring during macropinocytosis. These studies demonstrate that the localization of Hrs from the cytosol to the plasma membrane is important for coupling membrane dynamics to the cytosolic signaling events during macropinocytosis of KSHV.
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Abstract
Although the replicative life cycle of HIV within CD4 T cells is understood in molecular detail, less is known about how this human retrovirus promotes the loss of CD4 T lymphocytes. It is this cell death process that drives clinical progression to acquired immune deficiency syndrome (AIDS). Recent studies have highlighted how abortive infection of resting and thus nonpermissive CD4 T cells in lymphoid tissues triggers a lethal innate immune response against the incomplete DNA products generated by inefficient viral reverse transcription in these cells. Sensing of these DNA fragments results in pyroptosis, a highly inflammatory form of programmed cell death, that potentially further perpetuates chronic inflammation and immune activation. As discussed here, these studies cast CD4 T cell death during HIV infection in a different light. Further, they identify drug targets that may be exploited to both block CD4 T cell demise and the chronic inflammatory response generated during pyroptosis.
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Affiliation(s)
- Gilad Doitsh
- Gladstone Institute of Virology and Immunology, 1650 Owens Street, San Francisco, CA 94158, USA.
| | - Warner C Greene
- Gladstone Institute of Virology and Immunology, 1650 Owens Street, San Francisco, CA 94158, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA.
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Su C, Zhan G, Zheng C. Evasion of host antiviral innate immunity by HSV-1, an update. Virol J 2016; 13:38. [PMID: 26952111 PMCID: PMC4782282 DOI: 10.1186/s12985-016-0495-5] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 02/26/2016] [Indexed: 12/20/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1) infection triggers a rapid induction of host innate immune responses. The type I interferon (IFN) signal pathway is a central aspect of host defense which induces a wide range of antiviral proteins to control infection of incoming pathogens. In some cases, viral invasion also induces DNA damage response, autophagy, endoplasmic reticulum stress, cytoplasmic stress granules and other innate immune responses, which in turn affect viral infection. However, HSV-1 has evolved multiple strategies to evade host innate responses and facilitate its infection. In this review, we summarize the most recent findings on the molecular mechanisms utilized by HSV-1 to counteract host antiviral innate immune responses with specific focus on the type I IFN signal pathway.
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Affiliation(s)
- Chenhe Su
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, 215123, China.
| | - Guoqing Zhan
- Department of Infectious Disease, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei, 442000, China.
| | - Chunfu Zheng
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, 215123, China. .,Department of Microbiology, Immunology and Infectious Deseases, University of Calgary, Calgary, AB, T2N 4N1, Canada.
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Rosen A, Casciola-Rosen L. Autoantigens as Partners in Initiation and Propagation of Autoimmune Rheumatic Diseases. Annu Rev Immunol 2016; 34:395-420. [PMID: 26907212 DOI: 10.1146/annurev-immunol-032414-112205] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Systemic autoimmune diseases are characterized by specific targeting of a limited group of ubiquitously expressed autoantigens by the immune system. This review examines the mechanisms underlying their selection as immune targets. Initiation of autoimmune responses likely reflects the presentation of antigens with a distinct structure not previously encountered by the immune system, in a proimmune context (injury, malignancy, or infection). Causes of modified structure include somatic mutation and posttranslational modifications (including citrullination and proteolysis). Many autoantigens are components of multimolecular complexes, and some of the other components may provide adjuvant activity. Propagation of autoimmune responses appears to reflect a bidirectional interaction between the immune response and the target tissues in a mutually reinforcing cycle: Immune effector pathways generate additional autoantigen, which feeds further immune response. We propose that this resonance may be a critical principle underlying disease propagation, with specific autoantigens functioning as the hubs around which amplification occurs.
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Affiliation(s)
- Antony Rosen
- Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21224; ,
| | - Livia Casciola-Rosen
- Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21224; ,
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Chang PC, Campbell M, Robertson ES. Human Oncogenic Herpesvirus and Post-translational Modifications - Phosphorylation and SUMOylation. Front Microbiol 2016; 7:962. [PMID: 27379086 PMCID: PMC4911386 DOI: 10.3389/fmicb.2016.00962] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 06/03/2016] [Indexed: 01/05/2023] Open
Abstract
Pathogens, especially viruses, evolve abilities to utilize cellular machineries to facilitate their survival and propagation. Post-translational modifications (PTMs), especially phosphorylation and SUMOylation, that reversibly modulate the function and interactions of target proteins are among the most important features in cell signaling pathways. PTM-dependent events also serve as one of the favorite targets for viruses. Among the seven unambiguous human oncogenic viruses, hepatitis B virus (HBV), hepatitis C virus (HCV), Epstein-Barr virus (EBV), Kaposi's sarcoma-associated herpesvirus (KSHV), human papillomavirus (HPV), Human T lymphotrophic virus-1 (HTLV-1), and Merkel cell polyomavirus (MCPyV), two are herpesviruses. The life cycle of herpesviruses consists of latent and lytic phases and the rapid switch between these states includes global remodeling of the viral genome from heterochromatin-to-euchromatin. The balance between lytic replication and latency is essential for herpesvirus to maintain a persistent infection through a combination of viral propagation and evasion of the host immune response, which consequently may contribute to tumorigenesis. It is no surprise that the swift reversibility of PTMs, especially SUMOylation, a modification that epigenetically regulates chromatin structure, is a major hijack target of the host for oncogenic herpesviruses. In this brief review, we summarize the varied ways in which herpesviruses engage the host immune components through PTMs, focusing on phosphorylation and SUMOylation.
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Affiliation(s)
- Pei-Ching Chang
- Institute of Microbiology and Immunology, National Yang-Ming UniversityTaipei, China
- *Correspondence: Pei-Ching Chang, ; Erle S. Robertson,
| | - Mel Campbell
- UC Davis Cancer Center, University of California, Davis, DavisCA, USA
| | - Erle S. Robertson
- Department of Otorhinolaryngology and Tumor Virology Program, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, PhiladelphiaPA, USA
- *Correspondence: Pei-Ching Chang, ; Erle S. Robertson,
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