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Aboalroub AA, Al Azzam KM. Protein S-Nitrosylation: A Chemical Modification with Ubiquitous Biological Activities. Protein J 2024; 43:639-655. [PMID: 39068633 DOI: 10.1007/s10930-024-10223-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2024] [Indexed: 07/30/2024]
Abstract
Nitric oxide (NO) induces protein posttranslational modification (PTM), known as S-nitrosylation, which has started to gain attention as a critical regulator of thousands of substrate proteins. However, our understanding of the biological consequences of this emerging PTM is incomplete because of the limited number of identified S-nitrosylated proteins (S-NO proteins). Recent advances in detection methods have effectively contributed to broadening the spectrum of discovered S-NO proteins. This article briefly reviews the progress in S-NO protein detection methods and discusses how these methods are involved in characterizing the biological consequences of this PTM. Additionally, we provide insight into S-NO protein-related diseases, focusing on the role of these proteins in mitigating the severity of infectious diseases.
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Affiliation(s)
- Adam A Aboalroub
- Pharmacological and Diagnostic Research Center (PDRC), Department of Pharmaceutical Sciences, Faculty of Pharmacy, Al-Ahliyya Amman University, Amman, 19328, Jordan.
| | - Khaldun M Al Azzam
- Department of Chemistry, School of Science, The University of Jordan, Amman, 11942, Jordan
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2
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Eberhage J, Bresch IP, Ramani R, Viohl N, Buchta T, Rehfeld CL, Hinse P, Reubold TF, Brinkmann MM, Eschenburg S. Crystal structure of the tegument protein UL82 (pp71) from human cytomegalovirus. Protein Sci 2024; 33:e4915. [PMID: 38358250 PMCID: PMC10868460 DOI: 10.1002/pro.4915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 01/16/2024] [Accepted: 01/17/2024] [Indexed: 02/16/2024]
Abstract
Human cytomegalovirus (HCMV) is an opportunistic pathogen that infects a majority of the world population. It may cause severe disease in immunocompromised people and lead to pregnancy loss or grave disabilities of the fetus upon congenital infection. For effective replication and lifelong persistence in its host, HCMV relies on diverse functions of its tegument protein UL82, also known as pp71. Up to now, little is known about the molecular mechanisms underlying the multiple functions of this crucial viral protein. Here, we describe the X-ray structure of full-length UL82 to a resolution of 2.7 Å. A single polypeptide chain of 559 amino acids mainly folds into three ß-barrels. We show that UL82 forms a dimer in the crystal as well as in solution. We identify point mutations that disturb the dimerization interface and show that the mutant protein is monomeric in solution and upon expression in human cells. On the basis of the three-dimensional structure, we identify structural homologs of UL82 from other herpesviruses and analyze whether their functions are preserved in UL82. We demonstrate that UL82, despite its structural homology to viral deoxyuridinetriphosphatases (dUTPases), does not possess dUTPase activity. Prompted by the structural homology of UL82 to the ORF10 protein of murine herpesvirus 68 (MHV68), which is known to interact with the RNA export factor ribonucleic acid export 1 (Rae1), we performed coimmunoprecipitations and demonstrated that UL82 indeed interacts with Rae1. This suggests that HCMV UL82 may play a role in mRNA export from the nucleus similar to ORF10 encoded by the gammaherpesviruses MHV68.
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Affiliation(s)
- Jan Eberhage
- Institute for Biophysical ChemistryHannover Medical SchoolHannoverGermany
- Cluster of Excellence RESIST (EXC 2155)Hannover Medical SchoolHannoverGermany
| | - Ian P. Bresch
- Institute for Biophysical ChemistryHannover Medical SchoolHannoverGermany
- Cluster of Excellence RESIST (EXC 2155)Hannover Medical SchoolHannoverGermany
| | - Ramya Ramani
- Institute of GeneticsTechnische Universität BraunschweigGermany
- Virology and Innate Immunity Research GroupHelmholtz Centre for Infection Research (HZI)BraunschweigGermany
| | - Niklas Viohl
- Institute for Biophysical ChemistryHannover Medical SchoolHannoverGermany
- Cluster of Excellence RESIST (EXC 2155)Hannover Medical SchoolHannoverGermany
| | - Thalea Buchta
- Institute of GeneticsTechnische Universität BraunschweigGermany
| | - Christopher L. Rehfeld
- Institute for Biophysical ChemistryHannover Medical SchoolHannoverGermany
- Cluster of Excellence RESIST (EXC 2155)Hannover Medical SchoolHannoverGermany
| | - Petra Hinse
- Institute for Biophysical ChemistryHannover Medical SchoolHannoverGermany
| | - Thomas F. Reubold
- Institute for Biophysical ChemistryHannover Medical SchoolHannoverGermany
| | - Melanie M. Brinkmann
- Institute of GeneticsTechnische Universität BraunschweigGermany
- Virology and Innate Immunity Research GroupHelmholtz Centre for Infection Research (HZI)BraunschweigGermany
| | - Susanne Eschenburg
- Institute for Biophysical ChemistryHannover Medical SchoolHannoverGermany
- Cluster of Excellence RESIST (EXC 2155)Hannover Medical SchoolHannoverGermany
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3
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Hu MM, Shu HB. Mitochondrial DNA-triggered innate immune response: mechanisms and diseases. Cell Mol Immunol 2023; 20:1403-1412. [PMID: 37932533 PMCID: PMC10687031 DOI: 10.1038/s41423-023-01086-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 09/12/2023] [Indexed: 11/08/2023] Open
Abstract
Various cellular stress conditions trigger mitochondrial DNA (mtDNA) release from mitochondria into the cytosol. The released mtDNA is sensed by the cGAS-MITA/STING pathway, resulting in the induced expression of type I interferon and other effector genes. These processes contribute to the innate immune response to viral infection and other stress factors. The deregulation of these processes causes autoimmune diseases, inflammatory metabolic disorders and cancer. Therefore, the cGAS-MITA/STING pathway is a potential target for intervention in infectious, inflammatory and autoimmune diseases as well as cancer. In this review, we focus on the mechanisms underlying the mtDNA-triggered activation of the cGAS-MITA/STING pathway, the effects of the pathway under various physiological and pathological conditions, and advances in the development of drugs that target cGAS and MITA/STING.
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Affiliation(s)
- Ming-Ming Hu
- Department of Infectious Diseases, Medical Research Institute, Zhongnan Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Taikang Center for Life and Medical Sciences, College of Life Sciences, Wuhan University, Research Unit of Innate Immune and Inflammatory Diseases, Chinese Academy of Medical Sciences, Wuhan, 430072, China.
- Research Unit of Innate Immune and Inflammatory Diseases, Chinese Academy of Medical Sciences, Wuhan, 430072, China.
| | - Hong-Bing Shu
- Department of Infectious Diseases, Medical Research Institute, Zhongnan Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Taikang Center for Life and Medical Sciences, College of Life Sciences, Wuhan University, Research Unit of Innate Immune and Inflammatory Diseases, Chinese Academy of Medical Sciences, Wuhan, 430072, China.
- Research Unit of Innate Immune and Inflammatory Diseases, Chinese Academy of Medical Sciences, Wuhan, 430072, China.
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4
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Wu X, Zhou X, Wang S, Mao G. DNA damage response(DDR): a link between cellular senescence and human cytomegalovirus. Virol J 2023; 20:250. [PMID: 37915066 PMCID: PMC10621139 DOI: 10.1186/s12985-023-02203-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 10/04/2023] [Indexed: 11/03/2023] Open
Abstract
The DNA damage response (DDR) is a signaling cascade that is triggered by DNA damage, involving the halting of cell cycle progression and repair. It is a key event leading to senescence, which is characterized by irreversible cell cycle arrest and the senescence-associated secretory phenotype (SASP) that includes the expression of inflammatory cytokines. Human cytomegalovirus (HCMV) is a ubiquitous pathogen that plays an important role in the senescence process. It has been established that DDR is necessary for HCMV to replicate effectively. This paper reviews the relationship between DDR, cellular senescence, and HCMV, providing new sights for virus-induced senescence (VIS).
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Affiliation(s)
- Xinna Wu
- Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, 310030, China
| | - Xuqiang Zhou
- College of Life Science, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Sanying Wang
- Zhejiang Provincial Key Lab of Geriatrics & Geriatrics Institute of Zhejiang Province, Department of Geriatrics, Zhejiang Hospital, Hangzhou, 310030, China.
| | - Genxiang Mao
- Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, 310030, China.
- Zhejiang Provincial Key Lab of Geriatrics & Geriatrics Institute of Zhejiang Province, Department of Geriatrics, Zhejiang Hospital, Hangzhou, 310030, China.
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Roche KL, Remiszewski S, Todd MJ, Kulp JL, Tang L, Welsh AV, Barry AP, De C, Reiley WW, Wahl A, Garcia JV, Luftig MA, Shenk T, Tonra JR, Murphy EA, Chiang LW. An allosteric inhibitor of sirtuin 2 deacetylase activity exhibits broad-spectrum antiviral activity. J Clin Invest 2023; 133:e158978. [PMID: 37317966 PMCID: PMC10266789 DOI: 10.1172/jci158978] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 05/02/2023] [Indexed: 06/16/2023] Open
Abstract
Most drugs used to treat viral disease target a virus-coded product. They inhibit a single virus or virus family, and the pathogen can readily evolve resistance. Host-targeted antivirals can overcome these limitations. The broad-spectrum activity achieved by host targeting can be especially useful in combating emerging viruses and for treatment of diseases caused by multiple viral pathogens, such as opportunistic agents in immunosuppressed patients. We have developed a family of compounds that modulate sirtuin 2, an NAD+-dependent deacylase, and now report the properties of a member of that family, FLS-359. Biochemical and x-ray structural studies show that the drug binds to sirtuin 2 and allosterically inhibits its deacetylase activity. FLS-359 inhibits the growth of RNA and DNA viruses, including members of the coronavirus, orthomyxovirus, flavivirus, hepadnavirus, and herpesvirus families. FLS-359 acts at multiple levels to antagonize cytomegalovirus replication in fibroblasts, causing modest reductions in viral RNAs and DNA, together with a much greater reduction in infectious progeny, and it exhibits antiviral activity in humanized mouse models of infection. Our results highlight the potential of sirtuin 2 inhibitors as broad-spectrum antivirals and set the stage for further understanding of how host epigenetic mechanisms impact the growth and spread of viral pathogens.
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Affiliation(s)
- Kathryn L. Roche
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - Stacy Remiszewski
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - Matthew J. Todd
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - John L. Kulp
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - Liudi Tang
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - Alison V. Welsh
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - Ashley P. Barry
- Department of Molecular Genetics and Microbiology, Duke Center for Virology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Chandrav De
- International Center for the Advancement of Translational Science, Division of Infectious Diseases, Center for AIDS Research, University of North Carolina, School of Medicine, Chapel Hill, North Carolina, USA
| | | | - Angela Wahl
- International Center for the Advancement of Translational Science, Division of Infectious Diseases, Center for AIDS Research, University of North Carolina, School of Medicine, Chapel Hill, North Carolina, USA
| | - J. Victor Garcia
- International Center for the Advancement of Translational Science, Division of Infectious Diseases, Center for AIDS Research, University of North Carolina, School of Medicine, Chapel Hill, North Carolina, USA
| | - Micah A. Luftig
- Department of Molecular Genetics and Microbiology, Duke Center for Virology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Thomas Shenk
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - James R. Tonra
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - Eain A. Murphy
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
- Microbiology and Immunology Department, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Lillian W. Chiang
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
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Post-Translational Modifications of cGAS-STING: A Critical Switch for Immune Regulation. Cells 2022; 11:cells11193043. [PMID: 36231006 PMCID: PMC9563579 DOI: 10.3390/cells11193043] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 09/13/2022] [Accepted: 09/24/2022] [Indexed: 12/02/2022] Open
Abstract
Innate immune mechanisms initiate immune responses via pattern-recognition receptors (PRRs). Cyclic GMP-AMP synthase (cGAS), a member of the PRRs, senses diverse pathogenic or endogenous DNA and activates innate immune signaling pathways, including the expression of stimulator of interferon genes (STING), type I interferon, and other inflammatory cytokines, which, in turn, instructs the adaptive immune response development. This groundbreaking discovery has rapidly advanced research on host defense, cancer biology, and autoimmune disorders. Since cGAS/STING has enormous potential in eliciting an innate immune response, understanding its functional regulation is critical. As the most widespread and efficient regulatory mode of the cGAS-STING pathway, post-translational modifications (PTMs), such as the covalent linkage of functional groups to amino acid chains, are generally considered a regulatory mechanism for protein destruction or renewal. In this review, we discuss cGAS-STING signaling transduction and its mechanism in related diseases and focus on the current different regulatory modalities of PTMs in the control of the cGAS-STING-triggered innate immune and inflammatory responses.
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Nitric Oxide Attenuates Human Cytomegalovirus Infection yet Disrupts Neural Cell Differentiation and Tissue Organization. J Virol 2022; 96:e0012622. [PMID: 35862705 PMCID: PMC9327702 DOI: 10.1128/jvi.00126-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a prevalent betaherpesvirus that is asymptomatic in healthy individuals but can cause serious disease in immunocompromised patients. HCMV is also the leading cause of virus-mediated birth defects. Many of these defects manifest within the central nervous system and include microcephaly, sensorineural hearing loss, and cognitive developmental delays. Nitric oxide is a critical effector molecule produced as a component of the innate immune response during infection. Congenitally infected fetal brains show regions of brain damage, including necrotic foci with infiltrating macrophages and microglia, cell types that produce nitric oxide during infection. Using a 3-dimensional cortical organoid model, we demonstrate that nitric oxide inhibits HCMV spread and simultaneously disrupts neural rosette structures, resulting in tissue disorganization. Nitric oxide also attenuates HCMV replication in 2-dimensional cultures of neural progenitor cells (NPCs), a prominent cell type in cortical organoids that differentiate into neurons and glial cells. The multipotency factor SOX2 was decreased during nitric oxide exposure, suggesting that early neural differentiation is affected. Nitric oxide also reduced maximal mitochondrial respiration in both uninfected and infected NPCs. We determined that this reduction likely influences neural differentiation, as neurons (Tuj1+ GFAP- Nestin-) and glial populations (Tuj1- GFAP+ Nestin-) were reduced following differentiation. Our studies indicate a prominent, immunopathogenic role of nitric oxide in promoting developmental defects within the brain despite its antiviral activity during congenital HCMV infection. IMPORTANCE Human cytomegalovirus (HCMV) is the leading cause of virus-mediated congenital birth defects. Congenitally infected infants can have a variety of symptoms manifesting within the central nervous system. The use of 3-dimensional (3-D) cortical organoids to model infection of the fetal brain has advanced the current understanding of development and allowed broader investigation of the mechanisms behind disease. However, the impact of the innate immune molecule nitric oxide during HCMV infection has not been explored in neural cells or cortical 3-D models. Here, we investigated the effect of nitric oxide on cortical development during HCMV infection. We demonstrate that nitric oxide plays an antiviral role during infection yet results in disorganized cortical tissue. Nitric oxide contributes to differentiation defects of neuron and glial cells from neural progenitor cells despite inhibiting viral replication. Our results indicate that immunopathogenic consequences of nitric oxide during congenital infection promote developmental defects that undermine its antiviral activity.
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Albright ER, Mickelson CK, Kalejta RF. Human Cytomegalovirus UL138 Protein Inhibits the STING Pathway and Reduces Interferon Beta mRNA Accumulation during Lytic and Latent Infections. mBio 2021; 12:e0226721. [PMID: 34903048 PMCID: PMC8669494 DOI: 10.1128/mbio.02267-21] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 11/05/2021] [Indexed: 11/20/2022] Open
Abstract
The cGAS/STING/TBK1 (cyclic guanine monophosphate-AMP synthase/stimulator of interferon genes/Tank-binding kinase 1) innate immunity pathway is activated during human cytomegalovirus (HCMV) productive (lytic) replication in fully differentiated cells and during latency within incompletely differentiated myeloid cells. While multiple lytic-phase HCMV proteins neutralize steps along this pathway, none of them are expressed during latency. Here, we show that the latency-associated protein UL138 inhibits the cGAS/STING/TBK1 innate immunity pathway during transfections and infections, in fully differentiated cells and incompletely differentiated myeloid cells, and with loss of function and restoration of function approaches. UL138 inhibits the pathway downstream of STING but upstream of interferon regulatory factor 3 (IRF3) phosphorylation and NF-κB function and reduces the accumulation of interferon beta mRNA during both lytic and latent infections. IMPORTANCE While a cellular restriction versus viral countermeasure arms race between innate immunity and viral latency is expected, few examples have been documented. Our identification of the first HCMV latency protein that inactivates the cGAS/STING/TBK1 innate immune pathway opens the door to understanding how innate immunity, or its neutralization, impacts long-term persistence by HCMV and other latent viruses.
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Affiliation(s)
- Emily R. Albright
- Institute for Molecular Virology, University of Wisconsin—Madison, Madison, Wisconsin, USA
- McArdle Laboratory for Cancer Research, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Clayton K. Mickelson
- Institute for Molecular Virology, University of Wisconsin—Madison, Madison, Wisconsin, USA
- McArdle Laboratory for Cancer Research, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Robert F. Kalejta
- Institute for Molecular Virology, University of Wisconsin—Madison, Madison, Wisconsin, USA
- McArdle Laboratory for Cancer Research, University of Wisconsin—Madison, Madison, Wisconsin, USA
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9
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O’Connor CM, Sen GC. Innate Immune Responses to Herpesvirus Infection. Cells 2021; 10:2122. [PMID: 34440891 PMCID: PMC8394705 DOI: 10.3390/cells10082122] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/13/2021] [Accepted: 08/15/2021] [Indexed: 12/24/2022] Open
Abstract
Infection of a host cell by an invading viral pathogen triggers a multifaceted antiviral response. One of the most potent defense mechanisms host cells possess is the interferon (IFN) system, which initiates a targeted, coordinated attack against various stages of viral infection. This immediate innate immune response provides the most proximal defense and includes the accumulation of antiviral proteins, such as IFN-stimulated genes (ISGs), as well as a variety of protective cytokines. However, viruses have co-evolved with their hosts, and as such, have devised distinct mechanisms to undermine host innate responses. As large, double-stranded DNA viruses, herpesviruses rely on a multitude of means by which to counter the antiviral attack. Herein, we review the various approaches the human herpesviruses employ as countermeasures to the host innate immune response.
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Affiliation(s)
- Christine M. O’Connor
- Department of Genomic Medicine, Infection Biology Program, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44106, USA
| | - Ganes C. Sen
- Department of Inflammation and Immunity, Infection Biology Program, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44106, USA
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Mokry RL, Schumacher ML, Hogg N, Terhune SS. Nitric Oxide Circumvents Virus-Mediated Metabolic Regulation during Human Cytomegalovirus Infection. mBio 2020; 11:e02630-20. [PMID: 33323506 PMCID: PMC7773989 DOI: 10.1128/mbio.02630-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 10/30/2020] [Indexed: 12/25/2022] Open
Abstract
Nitric oxide is a versatile and critical effector molecule that can modulate many cellular functions. Although recognized as a regulator of infections, the inhibitory mechanism of nitric oxide against human cytomegalovirus (HCMV) replication remains elusive. We demonstrate that nitric oxide attenuates viral replication by interfering with HCMV-mediated modulation of several cellular processes. Nitric oxide exposure reduced HCMV genome synthesis and infectious viral progeny with cell-type-dependent differences observed. Mitochondrial respiration was severely reduced in both uninfected and HCMV-infected cells during exposure with little impact on ATP levels indicating changes in cellular metabolism. Metabolomics identified significantly altered small molecules in multiple pathways during nitric oxide exposure including nucleotide biosynthesis, tricarboxylic acid (TCA) cycle, and glutamine metabolism. Glutathione metabolites were increased coinciding with a reduction in the glutathione precursor glutamine. This shift was accompanied by increased antioxidant enzymes. Glutamine deprivation mimicked defects in HCMV replication and mitochondrial respiration observed during nitric oxide exposure. These data suggest that nitric oxide limits glutaminolysis by shuttling glutamine to glutathione synthesis. In addition, lipid intermediates were severely altered, which likely contributes to the observed increase in defective viral particles. Nitric oxide disrupts multiple cellular processes, and we had limited success in rescuing replication defects by supplementing with metabolic intermediates. Our studies indicate that nitric oxide attenuation of HCMV is multifactorial with interference in viral manipulation of cellular metabolism playing a central role.IMPORTANCE Human cytomegalovirus is a prevalent pathogen that can cause serious disease in patients with compromised immune systems, including transplant patients and during congenital infection. HCMV lytic replication likely occurs in localized sites of infection with immune cells infiltrating and releasing nitric oxide with other effector molecules. This nonspecific immune response results in both uninfected and infected cells exposed to high levels of nitric oxide. The absence of nitric oxide synthase has been associated with lethal HCMV infection. We demonstrate that nitric oxide inhibition of HCMV replication is multifactorial and cell type dependent. Our results indicate that nitric oxide controls replication by interfering with viral modulation of cellular metabolism while also affecting proliferation and mitochondrial respiration of neighboring uninfected cells. These studies identify the mechanism and contribution of nitric oxide during immune control of HCMV infection and provide insight into its role in other viral infections.
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Affiliation(s)
- Rebekah L Mokry
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Megan L Schumacher
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Neil Hogg
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Scott S Terhune
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Marquette University and Medical College of Wisconsin Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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