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Upregulated Proteasome Subunits in COVID-19 Patients: A Link with Hypoxemia, Lymphopenia and Inflammation. Biomolecules 2022; 12:biom12030442. [PMID: 35327634 PMCID: PMC8946050 DOI: 10.3390/biom12030442] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/07/2022] [Accepted: 03/11/2022] [Indexed: 02/01/2023] Open
Abstract
Severe COVID-19 disease leads to hypoxemia, inflammation and lymphopenia. Viral infection induces cellular stress and causes the activation of the innate immune response. The ubiquitin-proteasome system (UPS) is highly implicated in viral immune response regulation. The main function of the proteasome is protein degradation in its active form, which recognises and binds to ubiquitylated proteins. Some proteasome subunits have been reported to be upregulated under hypoxic and hyperinflammatory conditions. Here, we conducted a prospective cohort study of COVID-19 patients (n = 44) and age-and sex-matched controls (n = 20). In this study, we suggested that hypoxia could induce the overexpression of certain genes encoding for subunits from the α and β core of the 20S proteasome and from regulatory particles (19S and 11S) in COVID-19 patients. Furthermore, the gene expression of proteasome subunits was associated with lymphocyte count reduction and positively correlated with inflammatory molecular and clinical markers. Given the importance of the proteasome in maintaining cellular homeostasis, including the regulation of the apoptotic and pyroptotic pathways, these results provide a potential link between COVID-19 complications and proteasome gene expression.
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2
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Mehrzadi S, Karimi MY, Fatemi A, Reiter RJ, Hosseinzadeh A. SARS-CoV-2 and other coronaviruses negatively influence mitochondrial quality control: beneficial effects of melatonin. Pharmacol Ther 2021; 224:107825. [PMID: 33662449 PMCID: PMC7919585 DOI: 10.1016/j.pharmthera.2021.107825] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 12/25/2020] [Accepted: 02/22/2021] [Indexed: 12/19/2022]
Abstract
Coronaviruses (CoVs) are a group of single stranded RNA viruses, of which some of them such as SARS-CoV, MERS-CoV, and SARS-CoV-2 are associated with deadly worldwide human diseases. Coronavirus disease-2019 (COVID-19), a condition caused by SARS-CoV-2, results in acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) associated with high mortality in the elderly and in people with underlying comorbidities. Results from several studies suggest that CoVs localize in mitochondria and interact with mitochondrial protein translocation machinery to target their encoded products to mitochondria. Coronaviruses encode a number of proteins; this process is essential for viral replication through inhibiting degradation of viral proteins and host misfolded proteins including those in mitochondria. These viruses seem to maintain their replication by altering mitochondrial dynamics and targeting mitochondrial-associated antiviral signaling (MAVS), allowing them to evade host innate immunity. Coronaviruses infections such as COVID-19 are more severe in aging patients. Since endogenous melatonin levels are often dramatically reduced in the aged and because it is a potent anti-inflammatory agent, melatonin has been proposed to be useful in CoVs infections by altering proteasomal and mitochondrial activities. Melatonin inhibits mitochondrial fission due to its antioxidant and inhibitory effects on cytosolic calcium overload. The collective data suggests that melatonin may mediate mitochondrial adaptations through regulating both mitochondrial dynamics and biogenesis. We propose that melatonin may inhibit SARS-CoV-2-induced cell damage by regulating mitochondrial physiology.
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Affiliation(s)
- Saeed Mehrzadi
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran
| | | | - Alireza Fatemi
- Functional Neurosurgery Research Center, Shohada Tajrish Comprehensive Neurosurgical Center of Excellence, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Russel J Reiter
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Azam Hosseinzadeh
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran.
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3
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Vega-Valdez IR, Melvin N. R, José M. SQ, D. FGE, Marvin A. SU. Docking Simulations Exhibit Bortezomib and other Boron-containing Peptidomimetics as Potential Inhibitors of SARS-CoV-2 Main Protease. CURRENT CHEMICAL BIOLOGY 2021. [DOI: 10.2174/2212796814999201102195651] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Background::
Treatment of the COVID19 pandemic requires drug development.
Boron- containing compounds are attractive chemical agents, some
of them act as proteases inhibitors.
Objective::
The present study explores the role of boronic moieties in molecules
interacting on the binding site of the SARS-CoV-2 main protease.
Methods::
Conventional docking procedure was applied by assaying boron-free
and boron-containing compounds on the recently reported crystal structure of
SARS-CoV-2 main protease (PDB code: 6LU7). The set of 150 ligands includes
bortezomib and inhibitors of coronavirus proteases.
Results::
Most of the tested compounds share contact with key residues and pose
on the cleavage pocket. The compounds with a boron atom in their structure are
often estimated to have higher affinity than boron-free analogues.
Conclusion::
Interactions and the affinity of boron-containing peptidomimetics
strongly suggest that boron-moieties increase affinity on the main protease,
which is tested by in vitro assays. A Bis-boron-containing compound previously
tested active on SARS-virus protease and bortezomib were identified as potent ligands.
These advances may be relevant to drug designing, in addition to testing
available boron-containing drugs in patients with COVID19 infection.
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Affiliation(s)
- Iván R Vega-Valdez
- Seccion de Estudios de Posgrado e Investigacion, Escuela Superior de Medicina, Instituto Politecnico Nacional, Plan de San Luis y Diaz Miron s/n, Mexico City, 11340, Mexico
| | - Rosalez Melvin N.
- Seccion de Estudios de Posgrado e Investigacion, Escuela Superior de Medicina, Instituto Politecnico Nacional, Plan de San Luis y Diaz Miron s/n, Mexico City, 11340, Mexico
| | - Santiago-Quintana José M.
- Seccion de Estudios de Posgrado e Investigacion, Escuela Superior de Medicina, Instituto Politecnico Nacional, Plan de San Luis y Diaz Miron s/n, Mexico City, 11340, Mexico
| | - Farfán-García Eunice D.
- Seccion de Estudios de Posgrado e Investigacion, Escuela Superior de Medicina, Instituto Politecnico Nacional, Plan de San Luis y Diaz Miron s/n, Mexico City, 11340, Mexico
| | - Soriano-Ursúa Marvin A.
- Seccion de Estudios de Posgrado e Investigacion, Escuela Superior de Medicina, Instituto Politecnico Nacional, Plan de San Luis y Diaz Miron s/n, Mexico City, 11340, Mexico
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4
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Dehdashtian E, Pourhanifeh MH, Hemati K, Mehrzadi S, Hosseinzadeh A. Therapeutic application of nutraceuticals in diabetic nephropathy: Current evidence and future implications. Diabetes Metab Res Rev 2020; 36:e3336. [PMID: 32415805 DOI: 10.1002/dmrr.3336] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 05/06/2020] [Accepted: 05/08/2020] [Indexed: 12/11/2022]
Abstract
Diabetes mellitus (DM) is a common metabolic disease which may cause several complications, such as diabetic nephropathy (DN). The routine medical treatments used for DM are not effective enough and have many undesirable side effects. Moreover, the global increased prevalence of DM makes researchers try to explore potential complementary or alternative treatments. Nutraceuticals, as natural products with pharmaceutical agents, have a wide range of therapeutic properties in various pathologic conditions such as DN. However, the exact underlying mechanisms have not been fully understood. The purpose of this review is to summarize recent findings on the effect of nutraceuticals on DN.
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Affiliation(s)
- Ehsan Dehdashtian
- School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Hossein Pourhanifeh
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran
| | - Karim Hemati
- Department of Anesthesiology, Iran University of Medical Sciences, Tehran, Iran
| | - Saeed Mehrzadi
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Azam Hosseinzadeh
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran
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5
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Tundo GR, Sbardella D, Santoro AM, Coletta A, Oddone F, Grasso G, Milardi D, Lacal PM, Marini S, Purrello R, Graziani G, Coletta M. The proteasome as a druggable target with multiple therapeutic potentialities: Cutting and non-cutting edges. Pharmacol Ther 2020; 213:107579. [PMID: 32442437 PMCID: PMC7236745 DOI: 10.1016/j.pharmthera.2020.107579] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 05/05/2020] [Indexed: 01/10/2023]
Abstract
Ubiquitin Proteasome System (UPS) is an adaptable and finely tuned system that sustains proteostasis network under a large variety of physiopathological conditions. Its dysregulation is often associated with the onset and progression of human diseases; hence, UPS modulation has emerged as a promising new avenue for the development of treatments of several relevant pathologies, such as cancer and neurodegeneration. The clinical interest in proteasome inhibition has considerably increased after the FDA approval in 2003 of bortezomib for relapsed/refractory multiple myeloma, which is now used in the front-line setting. Thereafter, two other proteasome inhibitors (carfilzomib and ixazomib), designed to overcome resistance to bortezomib, have been approved for treatment-experienced patients, and a variety of novel inhibitors are currently under preclinical and clinical investigation not only for haematological malignancies but also for solid tumours. However, since UPS collapse leads to toxic misfolded proteins accumulation, proteasome is attracting even more interest as a target for the care of neurodegenerative diseases, which are sustained by UPS impairment. Thus, conceptually, proteasome activation represents an innovative and largely unexplored target for drug development. According to a multidisciplinary approach, spanning from chemistry, biochemistry, molecular biology to pharmacology, this review will summarize the most recent available literature regarding different aspects of proteasome biology, focusing on structure, function and regulation of proteasome in physiological and pathological processes, mostly cancer and neurodegenerative diseases, connecting biochemical features and clinical studies of proteasome targeting drugs.
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Affiliation(s)
- G R Tundo
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy.
| | | | - A M Santoro
- CNR, Institute of Crystallography, Catania, Italy
| | - A Coletta
- Department of Chemistry, University of Aarhus, Aarhus, Denmark
| | - F Oddone
- IRCCS-Fondazione Bietti, Rome, Italy
| | - G Grasso
- Department of Chemical Sciences, University of Catania, Catania, Italy
| | - D Milardi
- CNR, Institute of Crystallography, Catania, Italy
| | - P M Lacal
- Laboratory of Molecular Oncology, IDI-IRCCS, Rome, Italy
| | - S Marini
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | - R Purrello
- Department of Chemical Sciences, University of Catania, Catania, Italy
| | - G Graziani
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy.
| | - M Coletta
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy.
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6
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Curran CS, Rivera DR, Kopp JB. COVID-19 Usurps Host Regulatory Networks. Front Pharmacol 2020; 11:1278. [PMID: 32922297 PMCID: PMC7456869 DOI: 10.3389/fphar.2020.01278] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/03/2020] [Indexed: 01/08/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes coronavirus disease 2019 (COVID-19). SARS-CoV-2 binds the angiotensin-converting enzyme 2 (ACE2) on the cell surface and this complex is internalized. ACE2 serves as an endogenous inhibitor of inflammatory signals associated with four major regulator systems: the renin-angiotensin-aldosterone system (RAAS), the complement system, the coagulation cascade, and the kallikrein-kinin system (KKS). Understanding the pathophysiological effects of SARS-CoV-2 on these pathways is needed, particularly given the current lack of proven, effective treatments. The vasoconstrictive, prothrombotic and pro-inflammatory conditions induced by SARS-CoV-2 can be ascribed, at least in part, to the activation of these intersecting physiological networks. Moreover, patients with immune deficiencies, hypertension, diabetes, coronary heart disease, and kidney disease often have altered activation of these pathways, either due to underlying disease or to medications, and may be more susceptible to SARS-CoV-2 infection. Certain characteristic COVID-associated skin, sensory, and central nervous system manifestations may also be linked to viral activation of the RAAS, complement, coagulation, and KKS pathways. Pharmacological interventions that target molecules along these pathways may be useful in mitigating symptoms and preventing organ or tissue damage. While effective anti-viral therapies are critically needed, further study of these pathways may identify effective adjunctive treatments and patients most likely to benefit.
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Affiliation(s)
- Colleen S Curran
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Donna R Rivera
- Surveillance Research Program, Division of Cancer Control and Population Sciences, National Cancer Institute, National Institutes of Health, Rockville, MD, United States
| | - Jeffrey B Kopp
- Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
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7
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Becker T, Le-Trilling VTK, Trilling M. Cellular Cullin RING Ubiquitin Ligases: Druggable Host Dependency Factors of Cytomegaloviruses. Int J Mol Sci 2019; 20:E1636. [PMID: 30986950 PMCID: PMC6479302 DOI: 10.3390/ijms20071636] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 03/27/2019] [Accepted: 03/28/2019] [Indexed: 12/20/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a ubiquitous betaherpesvirus that frequently causes morbidity and mortality in individuals with insufficient immunity, such as transplant recipients, AIDS patients, and congenitally infected newborns. Several antiviral drugs are approved to treat HCMV infections. However, resistant HCMV mutants can arise in patients receiving long-term therapy. Additionally, side effects and the risk to cause birth defects limit the use of currently approved antivirals against HCMV. Therefore, the identification of new drug targets is of clinical relevance. Recent work identified DNA-damage binding protein 1 (DDB1) and the family of the cellular cullin (Cul) RING ubiquitin (Ub) ligases (CRLs) as host-derived factors that are relevant for the replication of human and mouse cytomegaloviruses. The first-in-class CRL inhibitory compound Pevonedistat (also called MLN4924) is currently under investigation as an anti-tumor drug in several clinical trials. Cytomegaloviruses exploit CRLs to regulate the abundance of viral proteins, and to induce the proteasomal degradation of host restriction factors involved in innate and intrinsic immunity. Accordingly, pharmacological blockade of CRL activity diminishes viral replication in cell culture. In this review, we summarize the current knowledge concerning the relevance of DDB1 and CRLs during cytomegalovirus replication and discuss chances and drawbacks of CRL inhibitory drugs as potential antiviral treatment against HCMV.
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Affiliation(s)
- Tanja Becker
- Institute for Virology, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany.
| | | | - Mirko Trilling
- Institute for Virology, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany.
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8
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V'kovski P, Gerber M, Kelly J, Pfaender S, Ebert N, Braga Lagache S, Simillion C, Portmann J, Stalder H, Gaschen V, Bruggmann R, Stoffel MH, Heller M, Dijkman R, Thiel V. Determination of host proteins composing the microenvironment of coronavirus replicase complexes by proximity-labeling. eLife 2019; 8:42037. [PMID: 30632963 PMCID: PMC6372286 DOI: 10.7554/elife.42037] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 01/11/2019] [Indexed: 12/31/2022] Open
Abstract
Positive-sense RNA viruses hijack intracellular membranes that provide niches for viral RNA synthesis and a platform for interactions with host proteins. However, little is known about host factors at the interface between replicase complexes and the host cytoplasm. We engineered a biotin ligase into a coronaviral replication/transcription complex (RTC) and identified >500 host proteins constituting the RTC microenvironment. siRNA-silencing of each RTC-proximal host factor demonstrated importance of vesicular trafficking pathways, ubiquitin-dependent and autophagy-related processes, and translation initiation factors. Notably, detection of translation initiation factors at the RTC was instrumental to visualize and demonstrate active translation proximal to replication complexes of several coronaviruses. Collectively, we establish a spatial link between viral RNA synthesis and diverse host factors of unprecedented breadth. Our data may serve as a paradigm for other positive-strand RNA viruses and provide a starting point for a comprehensive analysis of critical virus-host interactions that represent targets for therapeutic intervention. Coronaviruses can infect the nose and throat and are a main cause of the common cold. Infections are usually mild and short-lived, but sometimes they can turn nasty. In 2002 and 2012, two dangerous new coronaviruses emerged and caused diseases known as SARS and MERS. These viruses caused much more serious symptoms and in some cases proved deadly. The question is, why are some coronaviruses more dangerous than others? Scientists know that the body's response to virus infection can make a difference to whether someone had mild or severe disease. So, to understand why some coronaviruses cause a cold and others kill, they also need to learn how people react to virus infection. Coronaviruses hijack membranes inside cells and turn them into virus factories. Within these factories, the viruses build molecular machinery called replicase complexes to copy their genetic code, which is needed for the next generation of virus particles. The viruses steal and repurpose proteins from their host cell that will assist in the copying process. However, scientists do not yet know which host proteins are essential for the virus to multiply. So, to find out, V’kovski et al. developed a way to tag any host protein that came near the virus factories. The new technique involved attaching an enzyme called a biotin ligase to the replicase complex. This enzyme acts as a molecular label gun, attaching a chemical tag to any protein that comes within ten nanometres. The label gun revealed that more than 500 different proteins come into contact with the replicase complex. To find out what these proteins were doing, the next step was to switch off their genes one by one. This revealed the key cell machinery that coronaviruses hijack when they are replicating. It included the cell's cargo transport system, the waste disposal system, and the protein production system. Using these systems allows the viruses to copy their genetic code next to machines that can turn it straight into viral proteins. These new results provide clues about which proteins viruses actually need from their host cells. They also do not just apply to coronaviruses. Other viruses use similar strategies to complete their infection cycle. These findings could help researchers to understand more generally about how viruses multiply. In the future, this knowledge could lead to new ways to combat virus infections.
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Affiliation(s)
- Philip V'kovski
- Institute of Virology and Immunology IVI, Bern, Switzerland.,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.,Graduate School for Biomedical Science, University of Bern, Bern, Switzerland
| | - Markus Gerber
- Institute of Virology and Immunology IVI, Bern, Switzerland.,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Jenna Kelly
- Institute of Virology and Immunology IVI, Bern, Switzerland.,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.,Interfaculty Bioinformatics Unit, SIB Swiss Institute of Bioinformatics, University of Bern, Bern, Switzerland
| | - Stephanie Pfaender
- Institute of Virology and Immunology IVI, Bern, Switzerland.,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Nadine Ebert
- Institute of Virology and Immunology IVI, Bern, Switzerland.,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Sophie Braga Lagache
- Mass Spectrometry and Proteomics Core Facility, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Cedric Simillion
- Mass Spectrometry and Proteomics Core Facility, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland.,Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Jasmine Portmann
- Institute of Virology and Immunology IVI, Bern, Switzerland.,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Hanspeter Stalder
- Institute of Virology and Immunology IVI, Bern, Switzerland.,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Véronique Gaschen
- Division of Veterinary Anatomy, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Rémy Bruggmann
- Interfaculty Bioinformatics Unit, SIB Swiss Institute of Bioinformatics, University of Bern, Bern, Switzerland
| | - Michael H Stoffel
- Division of Veterinary Anatomy, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Manfred Heller
- Mass Spectrometry and Proteomics Core Facility, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Ronald Dijkman
- Institute of Virology and Immunology IVI, Bern, Switzerland.,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Volker Thiel
- Institute of Virology and Immunology IVI, Bern, Switzerland.,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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Huang X, Wei S, Ni S, Huang Y, Qin Q. Ubiquitin-Proteasome System Is Required for Efficient Replication of Singapore Grouper Iridovirus. Front Microbiol 2018; 9:2798. [PMID: 30534113 PMCID: PMC6275174 DOI: 10.3389/fmicb.2018.02798] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 10/31/2018] [Indexed: 12/20/2022] Open
Abstract
The ubiquitin-proteasome system (UPS) serves as the major intracellular pathway for protein degradation and plays crucial roles in several cellular processes. However, little is known about the potential actions of the UPS during fish virus infection. In this study, we elucidated the possible roles of UPS in the life cycle of Singapore grouper iridovirus (SGIV); a large DNA virus that usually causes serious systemic diseases with high mortality in groupers. Data from transcriptomic analysis of differentially expressed genes illustrated that expression of 65 genes within the UPS pathway, including ubiquitin encoding, ubiquitination, deubiquitination, and proteasome, were up- or down-regulated during SGIV infection. Using different proteasome inhibitors, inhibition of the proteasome decreased SGIV replication in vitro, accompanied by inhibition of virus assembly site formation, and viral gene transcription and protein transportation. Over-expression of ubiquitin partly rescued the inhibitory effect of ubiquitin inhibitor on SGIV replication, suggesting that UPS was required for fish iridovirus infection in vitro. Viral or host proteins regulated by proteasome inhibition during SGIV infection were investigated with two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Sixty-two differentially expressed proteins, including 15 viral and 47 host proteins, were identified after SGIV infection. The host proteins were involved in ubiquitin-mediated protein degradation, metabolism, cytoskeleton, macromolecular biosynthesis, and signal transduction. Among them, 11 proteins were negatively regulated upon MG132 treatment during SGIV infection. This is believed to be the first study to provide evidence that UPS was essential for fish virus infection and replication.
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Affiliation(s)
- Xiaohong Huang
- College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Shina Wei
- College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Songwei Ni
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Youhua Huang
- College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Qiwei Qin
- College of Marine Sciences, South China Agricultural University, Guangzhou, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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10
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Boldescu V, Behnam MAM, Vasilakis N, Klein CD. Broad-spectrum agents for flaviviral infections: dengue, Zika and beyond. Nat Rev Drug Discov 2017; 16:565-586. [PMID: 28473729 PMCID: PMC5925760 DOI: 10.1038/nrd.2017.33] [Citation(s) in RCA: 198] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Infections with flaviviruses, such as dengue, West Nile virus and the recently re-emerging Zika virus, are an increasing and probably lasting global risk. This Review summarizes and comments on the opportunities for broad-spectrum agents that are active against multiple flaviviruses. Broad-spectrum activity is particularly desirable to prepare for the next flaviviral epidemic, which could emerge from as-yet unknown or neglected viruses. Potential molecular targets for broad-spectrum antiflaviviral compounds include viral proteins, such as the viral protease or polymerase, and host targets that are exploited by these viruses during entry and replication, including α-glucosidase and proteins involved in nucleoside biosynthesis. Numerous compounds with broad-spectrum antiviral activity have already been identified by target-specific or phenotypic assays. For other compounds, broad-spectrum activity can be anticipated because of their mode of action and molecular targets.
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Affiliation(s)
- Veaceslav Boldescu
- Medicinal Chemistry, Institute of Pharmacy and Molecular Biotechnology IPMB, Heidelberg University, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
- Laboratory of Organic Synthesis and Biopharmaceuticals, Institute of Chemistry of the Academy of Sciences of Moldova, Academiei 3, 2028 Chisinau, Moldova
| | - Mira A. M. Behnam
- Medicinal Chemistry, Institute of Pharmacy and Molecular Biotechnology IPMB, Heidelberg University, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Nikos Vasilakis
- Dept. of Pathology and Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases and Institute for Human Infections and Immunity, 2.138D Keiller Bldg, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555–0609, USA
| | - Christian D. Klein
- Medicinal Chemistry, Institute of Pharmacy and Molecular Biotechnology IPMB, Heidelberg University, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
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11
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Yuan C, Liu W, Wang Y, Hou J, Zhang L, Wang G. Homologous recombination is a force in the evolution of canine distemper virus. PLoS One 2017; 12:e0175416. [PMID: 28394936 PMCID: PMC5386261 DOI: 10.1371/journal.pone.0175416] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 03/24/2017] [Indexed: 11/22/2022] Open
Abstract
Canine distemper virus (CDV) is the causative agent of canine distemper (CD) that is a highly contagious, lethal, multisystemic viral disease of receptive carnivores. The prevalence of CDV is a major concern in susceptible animals. Presently, it is unclear whether intragenic recombination can contribute to gene mutations and segment reassortment in the virus. In this study, 25 full-length CDV genome sequences were subjected to phylogenetic and recombinational analyses. The results of phylogenetic analysis, intragenic recombination, and nucleotide selection pressure indicated that mutation and recombination occurred in the six individual genes segment (H, F, P, N, L, M) of the CDV genome. The analysis also revealed pronounced genetic diversity in the CDV genome according to the geographically distinct lineages (genotypes), namely Asia-1, Asia-2, Asia-3, Europe, America-1, and America-2. The six recombination events were detected using SimPlot and RDP programs. The analysis of selection pressure demonstrated that a majority of the nucleotides in the CDV individual gene were under negative selection. Collectively, these data suggested that homologous recombination acts as a key force driving the genetic diversity and evolution of canine distemper virus.
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Affiliation(s)
- Chaowen Yuan
- College of life and health sciences, Northeastern University, Shenyang, Liaoning, China
| | - Wenxin Liu
- Laboratory of Hematology, Affiliated hospital of Guangdong Medical College, Zhanjiang, Guangzhou, China
| | - Yingbo Wang
- College of life and health sciences, Northeastern University, Shenyang, Liaoning, China
| | - Jinlong Hou
- College of life and health sciences, Northeastern University, Shenyang, Liaoning, China
| | - Liguo Zhang
- Center for Animal Disease Emergency of Liaoning province, Shenyang, Liaoning, China
| | - Guoqing Wang
- College of life and health sciences, Northeastern University, Shenyang, Liaoning, China
- * E-mail:
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Lu J, Chen WM, Geng CY, Durie BG, Huang XJ. Efficacy and Safety of Bortezomib in Multiple Myeloma Patients with Hepatitis B: A Multicenter Retrospective Study. Chin Med J (Engl) 2017; 129:274-8. [PMID: 26831227 PMCID: PMC4799569 DOI: 10.4103/0366-6999.174508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Background: The efficacy and safety evidence of bortezomib in multiple myeloma (MM) patients with hepatitis B is vacant. This study aimed to investigate the efficacy and safety of bortezomib in MM patients with hepatitis B in China. Methods: From 2006 to 2011, 739 newly diagnosed MM patients were screened for serum hepatitis B virus (HBV) biomarkers. HBV-infected patients were followed for HBV reactivation by monitoring of serum alanine transaminase (ALT) and HBV DNA load. The pattern of HBV reactivation in relation to bortezomib was evaluated. Seven hundred thirty-nine MM patients were included in this study. Results: The prevalence of MM patients infected with HBV was 3.4% (n = 25), of which 17 cases were treated with bortezomib. Bortezomib had no significant influence on liver function (ALT before and after treatment: 36.69 ± 8.90 U/L vs. 11.31 ± 2.74 U/L, P = 0.19) and HBV DNA of MM patients with HBV (detectable HBV DNA percentage: 5.9% vs. 11.8%, P = 0.12). Conclusions: Bortezomib can be used safely and effectively in MM patients with hepatitis B. HBV prophylaxis and surveillance are recommended during the MM treatment.
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Affiliation(s)
| | | | | | | | - Xiao-Jun Huang
- Department of Hematology, Peking University People's Hospital and Peking University Institute of Hematology, Beijing 100044, China
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13
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Cullin E3 ligases and their rewiring by viral factors. Biomolecules 2014; 4:897-930. [PMID: 25314029 PMCID: PMC4279162 DOI: 10.3390/biom4040897] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 08/20/2014] [Accepted: 09/15/2014] [Indexed: 02/06/2023] Open
Abstract
The ability of viruses to subvert host pathways is central in disease pathogenesis. Over the past decade, a critical role for the Ubiquitin Proteasome System (UPS) in counteracting host immune factors during viral infection has emerged. This counteraction is commonly achieved by the expression of viral proteins capable of sequestering host ubiquitin E3 ligases and their regulators. In particular, many viruses hijack members of the Cullin-RING E3 Ligase (CRL) family. Viruses interact in many ways with CRLs in order to impact their ligase activity; one key recurring interaction involves re-directing CRL complexes to degrade host targets that are otherwise not degraded within host cells. Removal of host immune factors by this mechanism creates a more amenable cellular environment for viral propagation. To date, a small number of target host factors have been identified, many of which are degraded via a CRL-proteasome pathway. Substantial effort within the field is ongoing to uncover the identities of further host proteins targeted in this fashion and the underlying mechanisms driving their turnover by the UPS. Elucidation of these targets and mechanisms will provide appealing anti-viral therapeutic opportunities. This review is focused on the many methods used by viruses to perturb host CRLs, focusing on substrate sequestration and viral regulation of E3 activity.
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Lei D, Li F, Su H, Liu J, Wei N, Wang X. Hepatic deficiency of COP9 signalosome subunit 8 induces ubiquitin-proteasome system impairment and Bim-mediated apoptosis in murine livers. PLoS One 2013; 8:e67793. [PMID: 23840878 PMCID: PMC3698095 DOI: 10.1371/journal.pone.0067793] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 05/27/2013] [Indexed: 11/19/2022] Open
Abstract
The COP9 signalosome (CSN), an evolutionally highly conserved protein complex composed of 8 unique subunits (CSN1 through CSN8) in higher eukaryotes, is purported to modulate protein degradation mediated by the ubiquitin-proteasome system (UPS) but this has not been demonstrated in a critical mitotic parenchymal organ of vertebrates. Hepatocyte-specific knockout of the Cops8 gene (HS-Csn8KO) was shown to cause massive hepatocyte apoptosis and liver malfunction but the underlying mechanism remains unclear. Here, we report that Csn8/CSN exerts profound impacts on hepatic UPS function and is critical to the stability of the pro-apoptotic protein Bim. Significant decreases in CIS (cytokine-inducible Src homology 2 domain-containing protein), a Bim receptor of a cullin2-based ubiquitin ligase, were found to co-exist with a marked increase of Bim proteins. Csn8 deficiency also significantly decreased 19S proteasome subunit Rpt5 and markedly increased high molecular weight neddylated and ubiquitinated proteins. The use of a surrogate UPS substrate further reveals severe impairment of UPS-mediated proteolysis in HS-Csn8KO livers. Inclusion body-like materials were accumulated in Csn8 deficient hepatocytes. In addition to Bim, massive hepatocyte apoptosis in HS-Csn8KO livers is also associated with elevated expression of other members of the Bcl2 family, including pro-apoptotic Bax as well as anti-apoptotic Bcl2 and Bcl-XL. Increased interaction between Bcl2 and Bim, but not between Bcl2 and Bax, was detected. Hence, it is concluded that hepatic CSN8 deficiency impairs the UPS in the liver and the resultant Bim upregulation likely plays an important role in triggering hepatocyte apoptosis via sequestering Bcl2 away from Bax.
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Affiliation(s)
- Daoxiong Lei
- Division of Basic Biomedical Sciences, The University of South Dakota Sanford School of Medicine, Vermillion, South Dakota, United States of America
- Department of Hepatobiliary Surgery, Tianjin 4th Central Hospital and The 4th Central Clinical College of Tianjin Medical University, Tianjin, China
| | - Faqian Li
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Huabo Su
- Division of Basic Biomedical Sciences, The University of South Dakota Sanford School of Medicine, Vermillion, South Dakota, United States of America
- Vascular Biology Center and Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States of America
| | - Jinbao Liu
- Division of Basic Biomedical Sciences, The University of South Dakota Sanford School of Medicine, Vermillion, South Dakota, United States of America
- Department of Pathophysiology, Guangzhou Medical College, Guangzhou, Guangdong, China
| | - Ning Wei
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Xuejun Wang
- Division of Basic Biomedical Sciences, The University of South Dakota Sanford School of Medicine, Vermillion, South Dakota, United States of America
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15
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Severe acute respiratory syndrome coronavirus replication is severely impaired by MG132 due to proteasome-independent inhibition of M-calpain. J Virol 2012; 86:10112-22. [PMID: 22787216 DOI: 10.1128/jvi.01001-12] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The ubiquitin-proteasome system (UPS) is involved in the replication of a broad range of viruses. Since replication of the murine hepatitis virus (MHV) is impaired upon proteasomal inhibition, the relevance of the UPS for the replication of the severe acute respiratory syndrome coronavirus (SARS-CoV) was investigated in this study. We demonstrate that the proteasomal inhibitor MG132 strongly inhibits SARS-CoV replication by interfering with early steps of the viral life cycle. Surprisingly, other proteasomal inhibitors (e.g., lactacystin and bortezomib) only marginally affected viral replication, indicating that the effect of MG132 is independent of proteasomal impairment. Induction of autophagy by MG132 treatment was excluded from playing a role, and no changes in SARS-CoV titers were observed during infection of wild-type or autophagy-deficient ATG5(-/-) mouse embryonic fibroblasts overexpressing the human SARS-CoV receptor, angiotensin-converting enzyme 2 (ACE2). Since MG132 also inhibits the cysteine protease m-calpain, we addressed the role of calpains in the early SARS-CoV life cycle using calpain inhibitors III (MDL28170) and VI (SJA6017). In fact, m-calpain inhibition with MDL28170 resulted in an even more pronounced inhibition of SARS-CoV replication (>7 orders of magnitude) than did MG132. Additional m-calpain knockdown experiments confirmed the dependence of SARS-CoV replication on the activity of the cysteine protease m-calpain. Taken together, we provide strong experimental evidence that SARS-CoV has unique replication requirements which are independent of functional UPS or autophagy pathways compared to other coronaviruses. Additionally, this work highlights an important role for m-calpain during early steps of the SARS-CoV life cycle.
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16
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Karnam G, Rygiel TP, Raaben M, Grinwis GCM, Coenjaerts FE, Ressing ME, Rottier PJM, de Haan CAM, Meyaard L. CD200 receptor controls sex-specific TLR7 responses to viral infection. PLoS Pathog 2012; 8:e1002710. [PMID: 22615569 PMCID: PMC3355091 DOI: 10.1371/journal.ppat.1002710] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 04/04/2012] [Indexed: 11/18/2022] Open
Abstract
Immunological checkpoints, such as the inhibitory CD200 receptor (CD200R), play a dual role in balancing the immune system during microbial infection. On the one hand these inhibitory signals prevent excessive immune mediated pathology but on the other hand they may impair clearance of the pathogen. We studied the influence of the inhibitory CD200-CD200R axis on clearance and pathology in two different virus infection models. We find that lack of CD200R signaling strongly enhances type I interferon (IFN) production and viral clearance and improves the outcome of mouse hepatitis corona virus (MHV) infection, particularly in female mice. MHV clearance is known to be dependent on Toll like receptor 7 (TLR7)-mediated type I IFN production and sex differences in TLR7 responses previously have been reported for humans. We therefore hypothesize that CD200R ligation suppresses TLR7 responses and that release of this inhibition enlarges sex differences in TLR7 signaling. This hypothesis is supported by our findings that in vivo administration of synthetic TLR7 ligand leads to enhanced type I IFN production, particularly in female Cd200(-/-) mice and that CD200R ligation inhibits TLR7 signaling in vitro. In influenza A virus infection we show that viral clearance is determined by sex but not by CD200R signaling. However, absence of CD200R in influenza A virus infection results in enhanced lung neutrophil influx and pathology in females. Thus, CD200-CD200R and sex are host factors that together determine the outcome of viral infection. Our data predict a sex bias in both beneficial and pathological immune responses to virus infection upon therapeutic targeting of CD200-CD200R.
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Affiliation(s)
- Guruswamy Karnam
- Department of Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Tomasz P. Rygiel
- Department of Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Matthijs Raaben
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Guy C. M. Grinwis
- Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Frank E. Coenjaerts
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Maaike E. Ressing
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Peter J. M. Rottier
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Cornelis A. M. de Haan
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Linde Meyaard
- Department of Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail:
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HIV-1 coinfection and morphine coexposure severely dysregulate hepatitis C virus-induced hepatic proinflammatory cytokine release and free radical production: increased pathogenesis coincides with uncoordinated host defenses. J Virol 2011; 85:11601-14. [PMID: 21900165 DOI: 10.1128/jvi.05239-11] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Coinfection with human immunodeficiency virus type-1 (HIV-1) and hepatitis C virus (HCV) is a global problem that is more prevalent in injection drug users because they have a higher risk for acquiring both viruses. The roles of inflammatory cytokines and oxidative stress were examined in HIV-1- and HCV-coinfected human hepatic cells. Morphine (the bioactive product of heroin), HIV-1 Tat and the MN strain gp120 (gp120(MN)) proteins, and X4 HIV-1(LAI/IIIB) and R5 HIV-1(SF162) isolates were used to study the mechanisms of disease progression in HCV (JFH1)-infected Huh7.5.1 cell populations. HCV increased tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) release and augmented production of reactive oxygen species (ROS), nitric oxide (NO), and 3-nitrotyrosine (3-NT) in Huh7.5.1 cells. Morphine preferentially affected R5-tropic, but not X4-tropic, HIV-1 interactions with Huh7.5.1 cells. HIV-1 proteins or isolates increased cytokine release in HCV-infected cells, while adding morphine to coinfected cells caused complex imbalances, significantly disrupting cytokine secretion depending on the cytokine, morphine concentration, exposure duration, and particular pathogen involved. Production of ROS, NO, and 3-NT increased significantly in HCV- and HIV-1-coexposed cells while exposure to morphine further increased ROS. The proteasome inhibitor MG132 significantly decreased oxyradicals, cytokine levels, and HCV protein levels. Our findings indicate that hepatic inflammation is increased by combined exposure to HCV and HIV-1, that the ubiquitin-proteasome system and NF-κB contribute to key aspects of the response, and that morphine further exacerbates the disruption of host defenses. The results suggest that opioid abuse and HIV-1 coinfection each further accelerate HCV-mediated liver disease by dysregulating immune defenses.
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Gustin JK, Moses AV, Früh K, Douglas JL. Viral takeover of the host ubiquitin system. Front Microbiol 2011; 2:161. [PMID: 21847386 PMCID: PMC3147166 DOI: 10.3389/fmicb.2011.00161] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 07/14/2011] [Indexed: 01/29/2023] Open
Abstract
Like the other more well-characterized post-translational modifications (phosphorylation, methylation, acetylation, acylation, etc.), the attachment of the 76 amino acid ubiquitin (Ub) protein to substrates has been shown to govern countless cellular processes. As obligate intracellular parasites, viruses have evolved the capability to commandeer many host processes in order to maximize their own survival, whether it be to increase viral production or to ensure the long-term survival of latently infected host cells. The first evidence that viruses could usurp the Ub system came from the DNA tumor viruses and Adenoviruses, each of which use Ub to dysregulate the host cell cycle (Scheffner et al., 1990; Querido et al., 2001). Today, the list of viruses that utilize Ub includes members from almost every viral class, encompassing both RNA and DNA viruses. Among these, there are examples of Ub usage at every stage of the viral life cycle, involving both ubiquitination and de-ubiquitination. In addition to viruses that merely modify the host Ub system, many of the large DNA viruses encode their own Ub modifying machinery. In this review, we highlight the latest discoveries regarding the myriad ways that viruses utilize Ub to their advantage.
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Affiliation(s)
- Jean K Gustin
- Vaccine and Gene Therapy Institute, Oregon Health & Science University Beaverton, OR, USA
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19
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Rotavirus replication requires a functional proteasome for effective assembly of viroplasms. J Virol 2011; 85:2781-92. [PMID: 21228236 DOI: 10.1128/jvi.01631-10] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The ubiquitin-proteasome system has been shown to play an important role in the replication cycle of different viruses. In this study, we describe a strong impairment of rotavirus replication upon inhibition of proteasomal activity. The effect was evidenced at the level of accumulation of viral proteins, viral RNA, and yield of infective particles. Kinetic studies revealed that the early steps of the replicative cycle following attachment, entry, and uncoating were clearly more sensitive to proteasome inhibition. We ruled out a direct inhibition of the viral polymerase activities and stability of viral proteins and found that the crucial step that was impaired by blocking proteasome activity was the assembly of new viroplasms. This was demonstrated by using chemical inhibitors of proteasome and by gene silencing using small interfering RNAs (siRNAs) specific for different proteasomal subunits and for the ubiquitin precursor RPS27A. In addition, we show that the effect of proteasome inhibition on virus infection is not due to increased levels of beta interferon (IFN-β).
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Proteasome inhibition in vivo promotes survival in a lethal murine model of severe acute respiratory syndrome. J Virol 2010; 84:12419-28. [PMID: 20861244 DOI: 10.1128/jvi.01219-10] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Ubiquitination is a critical regulator of the host immune response to viral infection, and many viruses, including coronaviruses, encode proteins that target the ubiquitination system. To explore the link between coronavirus infection and the ubiquitin system, we asked whether protein degradation by the 26S proteasome plays a role in severe coronavirus infections using a murine model of SARS-like pneumonitis induced by murine hepatitis virus strain 1 (MHV-1). In vitro, the pretreatment of peritoneal macrophages with inhibitors of the proteasome (pyrrolidine dithiocarbamate [PDTC], MG132, and PS-341) markedly inhibited MHV-1 replication at an early step in its replication cycle, as evidenced by inhibition of viral RNA production. Proteasome inhibition also blocked viral cytotoxicity in macrophages, as well as the induction of inflammatory mediators such as IP-10, gamma interferon (IFN-γ), and monocyte chemoattractant protein 1 (MCP-1). In vivo, intranasal inoculation of MHV-1 results in a lethal pneumonitis in A/J mice. Treatment of A/J mice with the proteasome inhibitor PDTC, MG132, or PS-341 led to 40% survival (P < 0.01), with a concomitant improvement of lung histology, reduced pulmonary viral replication, decreased pulmonary STAT phosphorylation, and reduced pulmonary inflammatory cytokine expression. These data demonstrate that inhibition of the cellular proteasome attenuates pneumonitis and cytokine gene expression in vivo by reducing MHV-1 replication and the resulting inflammatory response. The results further suggest that targeting the proteasome may be an effective new treatment for severe coronavirus infections.
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The ubiquitin-proteasome system plays an important role during various stages of the coronavirus infection cycle. J Virol 2010; 84:7869-79. [PMID: 20484504 DOI: 10.1128/jvi.00485-10] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ubiquitin-proteasome system (UPS) is a key player in regulating the intracellular sorting and degradation of proteins. In this study we investigated the role of the UPS in different steps of the coronavirus (CoV) infection cycle. Inhibition of the proteasome by different chemical compounds (i.e., MG132, epoxomicin, and Velcade) appeared to not only impair entry but also RNA synthesis and subsequent protein expression of different CoVs (i.e., mouse hepatitis virus [MHV], feline infectious peritonitis virus, and severe acute respiratory syndrome CoV). MHV assembly and release were, however, not appreciably affected by these compounds. The inhibitory effect on CoV protein expression did not appear to result from a general inhibition of translation due to induction of a cellular stress response by the inhibitors. Stress-induced phosphorylation of eukaryotic translation initiation factor 2alpha (eIF2alpha) generally results in impaired initiation of protein synthesis, but the sensitivity of MHV infection to proteasome inhibitors was unchanged in cells lacking a phosphorylatable eIF2alpha. MHV infection was affected not only by inhibition of the proteasome but also by interfering with protein ubiquitination. Viral protein expression was reduced in cells expressing a temperature-sensitive ubiquitin-activating enzyme E1 at the restrictive temperature, as well as in cells in which ubiquitin was depleted by using small interfering RNAs. Under these conditions, the susceptibility of the cells to virus infection was, however, not affected, excluding an important role of ubiquitination in virus entry. Our observations reveal an important role of the UPS in multiple steps of the CoV infection cycle and identify the UPS as a potential drug target to modulate the impact of CoV infection.
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