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Tidu A, Martin F. The interplay between cis- and trans-acting factors drives selective mRNA translation initiation in eukaryotes. Biochimie 2024; 217:20-30. [PMID: 37741547 DOI: 10.1016/j.biochi.2023.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/20/2023] [Accepted: 09/14/2023] [Indexed: 09/25/2023]
Abstract
Translation initiation consists in the assembly of the small and large ribosomal subunits on the start codon. This important step directly modulates the general proteome in living cells. Recently, genome wide studies revealed unexpected translation initiation events from unsuspected novel open reading frames resulting in the synthesis of a so-called 'dark proteome'. Indeed, the identification of the start codon by the translation machinery is a critical step that defines the translational landscape of the cell. Therefore, translation initiation is a highly regulated process in all organisms. In this review, we focus on the various cis- and trans-acting factors that rule the regulation of translation initiation in eukaryotes. Recent discoveries have shown that the guidance of the translation machinery for the choice of the start codon require sophisticated molecular mechanisms. In particular, the 5'UTR and the coding sequences contain cis-acting elements that trigger the use of AUG codons but also non-AUG codons to initiate protein synthesis. The use of these alternative start codons is also largely influenced by numerous trans-acting elements that drive selective mRNA translation in response to environmental changes.
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Affiliation(s)
- Antonin Tidu
- Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l'ARN, CNRS UPR9002, 2, allée Konrad Roentgen, F-67084 Strasbourg, France
| | - Franck Martin
- Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l'ARN, CNRS UPR9002, 2, allée Konrad Roentgen, F-67084 Strasbourg, France.
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2
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Grindheim AK, Patil SS, Nebigil CG, Désaubry L, Vedeler A. The flavagline FL3 interferes with the association of Annexin A2 with the eIF4F initiation complex and transiently stimulates the translation of annexin A2 mRNA. Front Cell Dev Biol 2023; 11:1094941. [PMID: 37250892 PMCID: PMC10214161 DOI: 10.3389/fcell.2023.1094941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 04/28/2023] [Indexed: 05/31/2023] Open
Abstract
Introduction: Annexin A2 (AnxA2) plays a critical role in cell transformation, immune response, and resistance to cancer therapy. Besides functioning as a calcium- and lipidbinding protein, AnxA2 also acts as an mRNA-binding protein, for instance, by interacting with regulatory regions of specific cytoskeleton-associated mRNAs. Methods and Results: Nanomolar concentrations of FL3, an inhibitor of the translation factor eIF4A, transiently increases the expression of AnxA2 in PC12 cells and stimulates shortterm transcription/translation of anxA2 mRNA in the rabbit reticulocyte lysate. AnxA2 regulates the translation of its cognate mRNA by a feed-back mechanism, which can partly be relieved by FL3. Results obtained using the holdup chromatographic retention assay results suggest that AnxA2 interacts transiently with eIF4E (possibly eIF4G) and PABP in an RNA-independent manner while cap pulldown experiments indicate a more stable RNA-dependent interaction. Short-term (2 h) treatment of PC12 cells with FL3 increases the amount of eIF4A in cap pulldown complexes of total lysates, but not of the cytoskeletal fraction. AnxA2 is only present in cap analogue-purified initiation complexes from the cytoskeletal fraction and not total lysates confirming that AnxA2 binds to a specific subpopulation of mRNAs. Discussion: Thus, AnxA2 interacts with PABP1 and subunits of the initiation complex eIF4F, explaining its inhibitory effect on translation by preventing the formation of the full eIF4F complex. This interaction appears to be modulated by FL3. These novel findings shed light on the regulation of translation by AnxA2 and contribute to a better understanding of the mechanism of action of eIF4A inhibitors.
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Affiliation(s)
- Ann Kari Grindheim
- Department of Biomedicine, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Sudarshan S. Patil
- Department of Biomedicine, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Canan G. Nebigil
- Regenerative Nanomedicine Laboratory (UMR1260), Faculty of Medicine, FMTS, INSERM-University of Strasbourg, Strasbourg, France
| | - Laurent Désaubry
- Regenerative Nanomedicine Laboratory (UMR1260), Faculty of Medicine, FMTS, INSERM-University of Strasbourg, Strasbourg, France
| | - Anni Vedeler
- Department of Biomedicine, Faculty of Medicine, University of Bergen, Bergen, Norway
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3
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Hong PP, Li C, Niu GJ, Zhao XF, Wang JX. White spot syndrome virus directly activates mTORC1 signaling to facilitate its replication via polymeric immunoglobulin receptor-mediated infection in shrimp. PLoS Pathog 2022; 18:e1010808. [PMID: 36067252 PMCID: PMC9481175 DOI: 10.1371/journal.ppat.1010808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 09/16/2022] [Accepted: 08/11/2022] [Indexed: 11/19/2022] Open
Abstract
Previous studies have shown that the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway has antiviral functions or is beneficial for viral replication, however, the detail mechanisms by which mTORC1 enhances viral infection remain unclear. Here, we found that proliferation of white spot syndrome virus (WSSV) was decreased after knockdown of mTor (mechanistic target of rapamycin) or injection inhibitor of mTORC1, rapamycin, in Marsupenaeus japonicus, which suggests that mTORC1 is utilized by WSSV for its replication in shrimp. Mechanistically, WSSV infects shrimp by binding to its receptor, polymeric immunoglobulin receptor (pIgR), and induces the interaction of its intracellular domain with Calmodulin. Calmodulin then promotes the activation of protein kinase B (AKT) by interaction with the pleckstrin homology (PH) domain of AKT. Activated AKT phosphorylates mTOR and results in the activation of the mTORC1 signaling pathway to promote its downstream effectors, ribosomal protein S6 kinase (S6Ks), for viral protein translation. Moreover, mTORC1 also phosphorylates eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1), which will result in the separation of 4EBP1 from eukaryotic translation initiation factor 4E (eIF4E) for the translation of viral proteins in shrimp. Our data revealed a novel pathway for WSSV proliferation in shrimp and indicated that mTORC1 may represent a potential clinical target for WSSV control in shrimp aquaculture. White spot syndrome virus (WSSV) is the causative pathogen of white spot disease (WSD) and represents the most destructive viral disease of shrimp. The virus has evolved various strategies to escape from host defenses or exploit host biological pathways for its reproduction. Studies on viral immune-escape mechanisms can provide new strategies for disease prevention and control in shrimp aquaculture. Mechanistic target of rapamycin (mTOR) plays a central role in the regulation of cell growth and metabolism, which nucleates two distinct protein complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2) with diverse functions at different levels of the signaling pathway. mTORC1 is reported to be exploited by viruses in their reproduction. However, the detail mechanism remains unclear. In this study, we identified a new mechanism of mTOR being hijacked by WSSV in shrimp (Marsupenaeus japonicus). WSSV infects shrimp by its receptor, pIgR and induces the interaction of the intracellular domain of pIgR with Calmodulin. Calmodulin subsequently promotes the activation of AKT by interaction with the pleckstrin homology domain of the kinase. Activated AKT phosphorylates mTOR and results in the activation of the mTORC1 signaling pathway to promote its downstream effectors, S6Ks, for viral protein synthesis. Moreover, mTORC1 also phosphorylates 4EBP1, which results in the separation of 4EBP1 from eIF4E for the translation of viral proteins in shrimp. Our study reveals a novel strategy for WSSV proliferation in shrimp and indicates that the components of mTORC1 may represent potential clinical targets for WSSV control in shrimp aquaculture.
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Affiliation(s)
- Pan-Pan Hong
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Cang Li
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Guo-Juan Niu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Xiao-Fan Zhao
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Jin-Xing Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, China
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, Shandong, China
- * E-mail:
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4
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Repurposing Antifungals for Host-Directed Antiviral Therapy? Pharmaceuticals (Basel) 2022; 15:ph15020212. [PMID: 35215323 PMCID: PMC8878022 DOI: 10.3390/ph15020212] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/04/2022] [Accepted: 02/08/2022] [Indexed: 02/04/2023] Open
Abstract
Because of their epidemic and pandemic potential, emerging viruses are a major threat to global healthcare systems. While vaccination is in general a straightforward approach to prevent viral infections, immunization can also cause escape mutants that hide from immune cell and antibody detection. Thus, other approaches than immunization are critical for the management and control of viral infections. Viruses are prone to mutations leading to the rapid emergence of resistant strains upon treatment with direct antivirals. In contrast to the direct interference with pathogen components, host-directed therapies aim to target host factors that are essential for the pathogenic replication cycle or to improve the host defense mechanisms, thus circumventing resistance. These relatively new approaches are often based on the repurposing of drugs which are already licensed for the treatment of other unrelated diseases. Here, we summarize what is known about the mechanisms and modes of action for a potential use of antifungals as repurposed host-directed anti-infectives for the therapeutic intervention to control viral infections.
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Vedagiri D, Gupta D, Mishra A, Krishna G, Bhaskar M, Sah V, Basu A, Nayak D, Kalia M, Valiya Veettil M, Harshan KH. Retinoic Acid-Inducible Gene I-Like Receptors Activate Snail To Limit RNA Viral Infections. J Virol 2021; 95:e0121621. [PMID: 34379517 PMCID: PMC8513471 DOI: 10.1128/jvi.01216-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 08/06/2021] [Indexed: 11/20/2022] Open
Abstract
Retinoic acid-inducible gene I-like receptors (RLRs) are important cytosolic pattern recognition receptors (PRRs) that sense viral RNA before mounting a response leading to the activation of type I IFNs. Several viral infections induce epithelial-mesenchymal transition (EMT), even as its significance remains unclear. Here, we show that EMT or an EMT-like process is a general response to viral infections. Our studies identify a previously unknown mechanism of regulation of an important EMT-transcription factor (EMT-TF) Snail during RNA viral infections and describe its possible implication. RNA viral infections, poly(I·C) transfection, and ectopic expression of RLR components induced Snail levels, indicating that RLR pathway could regulate its expression. Detailed examination using mitochondrial antiviral signaling protein knockout (MAVS-KO) cells established that MAVS is essential in this regulation. We identified two interferon-stimulated response elements (ISREs) in the SNAI1 promoter region and demonstrated that they are important in its transcriptional activation by phosphorylated IRF3. Increasing the levels of Snail activated RLR pathway and dramatically limited replication of the RNA viruses dengue virus, Japanese encephalitis virus (JEV), and vesicular stomatitis virus, pointing to their antiviral functions. Knockdown of Snail resulted in a considerable increase in the JEV titer, validating its antiviral functions. Finally, transforming growth factor β-mediated IFNB activation was dependent on Snail levels, confirming its important role in type I IFN activation. Thus, EMT-TF Snail is transcriptionally coregulated with type I IFN by RLRs and, in turn, promotes the RLR pathway, further strengthening the antiviral state in the cell. Our work identified an interesting mechanism of regulation of Snail that demonstrates potential coregulation of multiple innate antiviral pathways triggered by RLRs. Identification of antiviral functions of Snail also provides an opportunity to expand the sphere of RLR signaling. IMPORTANCE RLRs sense viral genomic RNA or the double-stranded RNA intermediates and trigger the activation of type I IFNs. Snail transcription factor, commonly associated with epithelial-mesenchymal transition (EMT), has been reported to facilitate EMT in several viral infections. Many of these reports are based on oncoviruses, leading to the speculation that EMT induced during infection is an important factor in the oncogenesis triggered by these infections. However, our studies reveal that EMT or EMT-like processes during viral infections have important functions in antiviral response. We have characterized a new mechanism of transcriptional regulation of Snail by IRF3 through interferon-stimulated response elements in their promoters, and this finding could have importance in nonviral contexts as well. We also identify that EMT-TF Snail promotes antiviral status of the infected cells through the RLR pathway. This study characterizes a new regulatory mechanism of activation of Snail and establishes its unidentified function in antiviral response.
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Affiliation(s)
- Dhiviya Vedagiri
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
- Academy for Scientific and Innovative Research, Ghaziabad, India
| | - Divya Gupta
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Anurag Mishra
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore, India
| | - Gayathri Krishna
- Virology Laboratory, Department of Biotechnology, Cochin University of Science and Technology, Cochin, Kerala, India
| | | | - Vishal Sah
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
- Academy for Scientific and Innovative Research, Ghaziabad, India
| | - Anirban Basu
- National Brain Research Centre, Manesar, Haryana, India
| | - Debasis Nayak
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore, India
| | - Manjula Kalia
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Mohanan Valiya Veettil
- Virology Laboratory, Department of Biotechnology, Cochin University of Science and Technology, Cochin, Kerala, India
| | - Krishnan Harinivas Harshan
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
- Academy for Scientific and Innovative Research, Ghaziabad, India
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6
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Gupta D, Parthasarathy H, Sah V, Tandel D, Vedagiri D, Reddy S, Harshan KH. Inactivation of SARS-CoV-2 by β-propiolactone causes aggregation of viral particles and loss of antigenic potential. Virus Res 2021; 305:198555. [PMID: 34487766 PMCID: PMC8416322 DOI: 10.1016/j.virusres.2021.198555] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 12/19/2022]
Abstract
Inactivated viral preparations are important resources in vaccine and antisera industry. Of the many vaccines that are being developed against COVID-19, inactivated whole-virus vaccines are also considered effective. β-propiolactone (BPL) is a widely used chemical inactivator of several viruses. Here, we analyze various concentrations of BPL to effectively inactivate SARS-CoV-2 and their effects on the biochemical properties of the virion particles. BPL at 1:2000 (v/v) concentrations effectively inactivated SARS-CoV-2. However, higher BPL concentrations resulted in the loss of both protein content as well as the antigenic integrity of the structural proteins. Higher concentrations also caused substantial aggregation of the virion particles possibly resulting in insufficient inactivation, and a loss in antigenic potential. We also identify that the viral RNA content in the culture supernatants can be a direct indicator of their antigenic content. Our findings may have important implications in the vaccine and antisera industry during COVID-19 pandemic.
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Affiliation(s)
- Divya Gupta
- Centre for Cellular and Molecular Biology, Hyderabad 500007, India
| | | | - Vishal Sah
- Centre for Cellular and Molecular Biology, Hyderabad 500007, India; Academy for Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Dixit Tandel
- Centre for Cellular and Molecular Biology, Hyderabad 500007, India; Academy for Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Dhiviya Vedagiri
- Centre for Cellular and Molecular Biology, Hyderabad 500007, India; Academy for Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Shashikala Reddy
- Department of Microbiology, Osmania Medical College, Koti, Hyderabad 500095, Telangana, India
| | - Krishnan H Harshan
- Centre for Cellular and Molecular Biology, Hyderabad 500007, India; Academy for Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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7
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Long-Term Hypoxia Maintains a State of Dedifferentiation and Enhanced Stemness in Fetal Cardiovascular Progenitor Cells. Int J Mol Sci 2021; 22:ijms22179382. [PMID: 34502291 PMCID: PMC8431563 DOI: 10.3390/ijms22179382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/20/2021] [Accepted: 08/25/2021] [Indexed: 12/03/2022] Open
Abstract
Early-stage mammalian embryos survive within a low oxygen tension environment and develop into fully functional, healthy organisms despite this hypoxic stress. This suggests that hypoxia plays a regulative role in fetal development that influences cell mobilization, differentiation, proliferation, and survival. The long-term hypoxic environment is sustained throughout gestation. Elucidation of the mechanisms by which cardiovascular stem cells survive and thrive under hypoxic conditions would benefit cell-based therapies where stem cell survival is limited in the hypoxic environment of the infarcted heart. The current study addressed the impact of long-term hypoxia on fetal Islet-1+ cardiovascular progenitor cell clones, which were isolated from sheep housed at high altitude. The cells were then cultured in vitro in 1% oxygen and compared with control Islet-1+ cardiovascular progenitor cells maintained at 21% oxygen. RT-PCR, western blotting, flow cytometry, and migration assays evaluated adaptation to long term hypoxia in terms of survival, proliferation, and signaling. Non-canonical Wnt, Notch, AKT, HIF-2α and Yap1 transcripts were induced by hypoxia. The hypoxic niche environment regulates these signaling pathways to sustain the dedifferentiation and survival of fetal cardiovascular progenitor cells.
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Mudaliar P, Pradeep P, Abraham R, Sreekumar E. Targeting cap-dependent translation to inhibit Chikungunya virus replication: selectivity of p38 MAPK inhibitors to virus-infected cells due to autophagy-mediated down regulation of phospho-ERK. J Gen Virol 2021; 102. [PMID: 34328830 DOI: 10.1099/jgv.0.001629] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The 5' capped, message-sense RNA genome of Chikungunya virus (CHIKV) utilizes the host cell machinery for translation. Translation is regulated by eIF2 alpha at the initiation phase and by eIF4F at cap recognition. Translational suppression by eIF2 alpha phosphorylation occurs as an early event in many alphavirus infections. We observe that in CHIKV-infected HEK293 cells, this occurs as a late event, by which time the viral replication has reached an exponential phase, implying its minimal role in virus restriction. The regulation by eIF4F is mediated through the PI3K-Akt-mTOR, p38 MAPK and RAS-RAF-MEK-ERK pathways. A kinetic analysis revealed that CHIKV infection did not modulate AKT phosphorylation, but caused a significant reduction in p38 MAPK phosphorylation. It caused degradation of phospho-ERK 1/2 by increased autophagy, leaving the PI3K-Akt-mTOR and p38 MAPK pathways for pharmacological targeting. mTOR inhibition resulted in moderate reduction in viral titre, but had no effect on CHIKV E2 protein expression, indicating a minimal role of the mTOR complex in virus replication. Inhibition of p38 MAPK using SB202190 caused a significant reduction in viral titre and CHIKV E2 and nsP3 protein expression. Furthermore, inhibiting the two pathways together did not offer any synergism, indicating that inhibiting the p38 MAPK pathway alone is sufficient to cause restriction of CHIKV replication. Meanwhile, in uninfected cells the fully functional RAS-RAF-MEK-ERK pathway can circumvent the effect of p38 MAPK inhibition on cap-dependent translation. Thus, our results show that host-directed antiviral strategies targeting cellular p38 MAPK are worth exploring against Chikungunya as they could be selective against CHIKV-infected cells with minimal effects on uninfected host cells.
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Affiliation(s)
- Prashant Mudaliar
- Molecular Virology Laboratory, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram 695014, Kerala, India.,Research Centre, University of Kerala, Thiruvananthapuram 695034, Kerala, India
| | - Parvanendhu Pradeep
- Molecular Virology Laboratory, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram 695014, Kerala, India.,Research Centre, University of Kerala, Thiruvananthapuram 695034, Kerala, India
| | - Rachy Abraham
- Molecular Virology Laboratory, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram 695014, Kerala, India
| | - Easwaran Sreekumar
- Molecular Virology Laboratory, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram 695014, Kerala, India
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Marinov R, Markova N, Krumova S, Yotovska K, Zaharieva MM, Genova-Kalou P. Antiviral properties of chalcones and their synthetic derivatives: a mini review. PHARMACIA 2020. [DOI: 10.3897/pharmacia.67.e53842] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Chalcones (natural or synthetic derivatives) are aromatic ketones possessing a central backbone that form a core for variety important compounds with different substitutions. Recent scientific advances show that chalcones exhibit different bio-medical activities, including antiviral, which is related to the variety substitutions. This review provides general information on the origin, sources, virucidal and direct antiviral properties of chalcones in vitro, as well as a brief overview of the possible application and molecular modes of action of these compounds. The antiviral effect of chalcones probably results from the disruption of the different stage of viral replication cycle, inhibition of viral or cell enzymes, induction of apoptosis and others. Structural requirements for antiviral activities vary according to the mechanisms of action. Based on the published information, it could be considered that synthetic chalcones are very perspective antiviral candidates and deserve further studies for elucidating of their pharmacological potential.
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Shen Z, Zhang G, Yang Y, Li M, Yang S, Peng G. Lysine 164 is critical for SARS-CoV-2 Nsp1 inhibition of host gene expression. J Gen Virol 2020; 102. [PMID: 33151142 PMCID: PMC8116783 DOI: 10.1099/jgv.0.001513] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The emerging pathogen severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused social and economic disruption worldwide, infecting over 9.0 million people and killing over 469 000 by 24 June 2020. Unfortunately, no vaccine or antiviral drug that completely eliminates the transmissible disease coronavirus disease 2019 (COVID-19) has been developed to date. Given that coronavirus nonstructural protein 1 (nsp1) is a good target for attenuated vaccines, it is of great significance to explore the detailed characteristics of SARS-CoV-2 nsp1. Here, we first confirmed that SARS-CoV-2 nsp1 had a conserved function similar to that of SARS-CoV nsp1 in inhibiting host-protein synthesis and showed greater inhibition efficiency, as revealed by ribopuromycylation and Renilla luciferase (Rluc) reporter assays. Specifically, bioinformatics and biochemical experiments showed that by interacting with 40S ribosomal subunit, the lysine located at amino acid 164 (K164) was the key residue that enabled SARS-CoV-2 nsp1 to suppress host gene expression. Furthermore, as an inhibitor of host-protein expression, SARS-CoV-2 nsp1 contributed to cell-cycle arrest in G0/G1 phase, which might provide a favourable environment for virus production. Taken together, this research uncovered the detailed mechanism by which SARS-CoV-2 nsp1 K164 inhibited host gene expression, laying the foundation for the development of attenuated vaccines based on nsp1 modification.
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Affiliation(s)
- Zhou Shen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, PR China
| | - Guangxu Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
| | - Yilin Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, PR China
| | - Mengxia Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, PR China
| | - Siqi Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
| | - Guiqing Peng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, PR China
- *Correspondence: Guiqing Peng,
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11
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Mechanistic Target of Rapamycin Signaling Activation Antagonizes Autophagy To Facilitate Zika Virus Replication. J Virol 2020; 94:JVI.01575-20. [PMID: 32878890 DOI: 10.1128/jvi.01575-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 08/25/2020] [Indexed: 12/11/2022] Open
Abstract
Zika virus (ZIKV), a mosquito-transmitted flavivirus, is linked to microcephaly and other neurological defects in neonates and Guillain-Barré syndrome in adults. The molecular mechanisms regulating ZIKV infection and pathogenic outcomes are incompletely understood. Signaling by the mechanistic (mammalian) target of rapamycin (mTOR) kinase is important for cell survival and proliferation, and viruses are known to hijack this pathway for their replication. Here, we show that in human neuronal precursors and glial cells in culture, ZIKV infection activates both mTOR complex 1 (mTORC1) and mTORC2. Inhibition of mTOR kinase by Torin1 or rapamycin results in reduction in ZIKV protein expression and progeny production. Depletion of Raptor, the defining subunit of mTORC1, by small interfering RNA (siRNA) negatively affects ZIKV protein expression and viral replication. Although depletion of Rictor, the unique subunit of mTORC2, or the mTOR kinase itself also inhibits the viral processes, the extent of inhibition is less pronounced. Autophagy is transiently induced early by ZIKV infection, and impairment of autophagosome elongation by the class III phosphatidylinositol 3-kinase (PI3K) inhibitor 3-methyladenine (3-MA) enhances viral protein accumulation and progeny production. mTOR phosphorylates and inactivates ULK1 (S757) at later stages of ZIKV infection, suggesting a link between autophagy inhibition and mTOR activation by ZIKV. Accordingly, inhibition of ULK1 (by MRT68921) or autophagy (by 3-MA) reversed the effects of mTOR inhibition, leading to increased levels of ZIKV protein expression and progeny production. Our results demonstrate that ZIKV replication requires the activation of both mTORC1 and mTORC2, which negatively regulates autophagy to facilitate ZIKV replication.IMPORTANCE The re-emergence of Zika virus (ZIKV) and its association with neurological complications necessitates studies on the molecular mechanisms that regulate ZIKV pathogenesis. The mTOR signaling cascade is tightly regulated and central to normal neuronal development and survival. Disruption of mTOR signaling can result in neurological abnormalities. In the studies reported here, we demonstrate for the first time that ZIKV infection results in activation of both mTORC1 and mTORC2 to promote virus replication. Although autophagy is activated early in infection to counter virus replication, it is subsequently suppressed by mTOR. These results reveal critical roles of mTOR signaling and autophagy in ZIKV infection and point to a possible mechanism underlying ZIKV-induced pathogenesis. Elucidating the role of mTOR signaling in ZIKV infection will provide insights into the mechanisms of ZIKV-induced neurological complications and potential targets for therapeutic approaches.
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12
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Johri MK, Lashkari HV, Gupta D, Vedagiri D, Harshan KH. mTORC1 restricts hepatitis C virus RNA replication through ULK1-mediated suppression of miR-122 and facilitates post-replication events. J Gen Virol 2020; 101:86-95. [PMID: 31821132 DOI: 10.1099/jgv.0.001356] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR), an important kinase that assimilates several upstream signals, associates into two functional complexes, mTORC1 and mTORC2. In this study, we demonstrate that HCV infection activates mTORC1 that functions in important antiviral response. Pharmacological inhibition of mTOR complexes augmented cellular HCV RNA levels, the observation confirmed further by Raptor depletion, indicating antiviral roles of mTORC1. ULK1 depletion phenocopied mTOR inhibition and thus suggested that mTORC1 restricts HCV replication through ULK1. We reveal that ULK1 depletion augmented the levels of miR-122, a critical host factor for HCV replication, thus possibly regulating HCV replication. The increase in HCV RNA levels, however, failed to augment intracellular infectious virion production, reflecting a lower rate of virion assembly. Higher intracellular HCV RNA levels, however, did not result in a corresponding increase in HCV RNA and infectious titres in mTOR inhibited supernatants, but in contrast showed a consistent drop, confirming defective viral assembly caused by the inhibition. Consistent with this, the mTOR activator caused a significant drop in HCV RNA levels both in infected cells and in the supernatant. Our results demonstrate that ULK1 depletion did not affect autophagy, suggesting that ULK1-mediated HCV regulation is autophagy independent. Together, our data demonstrate that mTORC1 functions to suppress HCV RNA replication, but facilitates the virion packaging and release. Our studies reveal that the activation of mTOR by HCV infection is an antiviral measure by the cells.
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Affiliation(s)
- Manish Kumar Johri
- Academy of Scientific and Innovative Research (AcSIR), CSIR-CCMB Campus, Hyderabad, India.,CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad-500007, India
| | | | - Divya Gupta
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad-500007, India
| | - Dhiviya Vedagiri
- Academy of Scientific and Innovative Research (AcSIR), CSIR-CCMB Campus, Hyderabad, India.,CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad-500007, India
| | - Krishnan Harinivas Harshan
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad-500007, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-CCMB Campus, Hyderabad, India
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13
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Porcine epidemic diarrhea virus infection blocks cell cycle and induces apoptosis in pig intestinal epithelial cells. Microb Pathog 2020; 147:104378. [PMID: 32653434 PMCID: PMC7347497 DOI: 10.1016/j.micpath.2020.104378] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 05/17/2020] [Accepted: 07/02/2020] [Indexed: 12/16/2022]
Abstract
Porcine epidemic diarrhea virus (PEDV) is responsible for the acute infectious swine disease porcine epidemic diarrhea (PED). PED causes damage to the intestine, including villus atrophy and shedding, leading to serious economic losses to the pig industry worldwide. We carried out an in vitro study to investigate cell apoptosis and the cell cycle in a PEDV-infected host using transcriptomic shotgun sequencing (RNA-Seq) to study gene responses to PEDV infection. Results revealed that the PEDV infection reduced proliferation activity, blocked the cell cycle at S-phase and induced apoptosis in IPEC-J2 cells. The expression of gene levels related to ribosome proteins and oxidative phosphorylation were significantly up-regulated post-PEDV infection. Although the significantly down-regulated on PI3K/Akt signaling pathway post-PEDV infection, the regulator-related genes of mTOR signaling pathway exerted significantly up-regulated or down-regulated in IPEC-J2 cells. These results indicated that ribosome proteins and oxidative phosphorylation process were widely involved in the pathological changes and regulation of host cells caused by PEDV infection, and PI3K/AKT and mTOR signaling pathways played a vital role in antiviral regulation in IPEC-J2 cells. These data might provide new insights into the specific pathogenesis of PEDV infection and pave the way for the development of effective therapeutic strategies.
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14
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Zhan Y, Yu S, Yang S, Qiu X, Meng C, Tan L, Song C, Liao Y, Liu W, Sun Y, Ding C. Newcastle Disease virus infection activates PI3K/Akt/mTOR and p38 MAPK/Mnk1 pathways to benefit viral mRNA translation via interaction of the viral NP protein and host eIF4E. PLoS Pathog 2020; 16:e1008610. [PMID: 32603377 PMCID: PMC7326156 DOI: 10.1371/journal.ppat.1008610] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 05/06/2020] [Indexed: 02/06/2023] Open
Abstract
Newcastle disease virus (NDV), a member of the Paramyxoviridae family, can activate PKR/eIF2α signaling cascade to shutoff host and facilitate viral mRNA translation during infection, however, the mechanism remains unclear. In this study, we revealed that NDV infection up-regulated host cap-dependent translation machinery by activating PI3K/Akt/mTOR and p38 MAPK/Mnk1 pathways. In addition, NDV infection induced p38 MAPK/Mnk1 signaling participated 4E-BP1 hyperphosphorylation for efficient viral protein synthesis when mTOR signaling is inhibited. Furthermore, NDV NP protein was found to be important for selective cap-dependent translation of viral mRNAs through binding to eIF4E during NDV infection. Taken together, NDV infection activated multiple signaling pathways for selective viral protein synthesis in infected cells, via interaction between viral NP protein and host translation machinery. Our results may help to design novel targets for therapeutic intervention against NDV infection and to understand the NDV anti-oncolytic mechanism. Viruses are obligate intracellular parasites and have no protein translation machinry of their own. Therefore, viruses remain exclusively dependent on host translation machinery to ensure viral protein synthesis and progeny virion production during infection. We previous reported that Newcastle disease virus (NDV) shutoff host and facilitate viral mRNA translation by activating PKR/eIF2α signaling cascade. Here, we demonstrated that NDV infection up-regulated host cap-dependent translation machinery by activating PI3K/Akt/mTOR and p38 MAPK/Mnk1 pathways. Furthermore, NDV NP protein was found to be important for selective cap-dependent translation of viral mRNAs. Our findings highlight a new strategy how virus used host translation machinery for selective viral protein synthesis.
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Affiliation(s)
- Yuan Zhan
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, P.R. China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, P.R. China
| | - Shen Yang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, P.R. China
| | - Xusheng Qiu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, P.R. China
| | - Chunchun Meng
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, P.R. China
| | - Lei Tan
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, P.R. China
| | - Cuiping Song
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, P.R. China
| | - Ying Liao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, P.R. China
| | - Weiwei Liu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, P.R. China
| | - Yingjie Sun
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, P.R. China
- * E-mail: (YS); (CD)
| | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, P.R. China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, P.R. China
- * E-mail: (YS); (CD)
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15
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Zhou ZD, Selvaratnam T, Lee JCT, Chao YX, Tan EK. Molecular targets for modulating the protein translation vital to proteostasis and neuron degeneration in Parkinson's disease. Transl Neurodegener 2019; 8:6. [PMID: 30740222 PMCID: PMC6360798 DOI: 10.1186/s40035-019-0145-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 01/14/2019] [Indexed: 12/13/2022] Open
Abstract
Parkinson's disease (PD) is the most common neurodegenerative movement disorder, which is characterized by the progressive loss of dopaminergic neurons in the Substantia Nigra pars compacta concomitant with Lewy body formation in affected brain areas. The detailed pathogenic mechanisms underlying the selective loss of dopaminergic neurons in PD are unclear, and no drugs or treatments have been developed to alleviate progressive dopaminergic neuron degeneration in PD. However, the formation of α-synuclein-positive protein aggregates in Lewy body has been identified as a common pathological feature of PD, possibly stemming from the consequence of protein misfolding and dysfunctional proteostasis. Proteostasis is the mechanism for maintaining protein homeostasis via modulation of protein translation, enhancement of chaperone capacity and the prompt clearance of misfolded protein by the ubiquitin proteasome system and autophagy. Deregulated protein translation and impaired capacities of chaperone or protein degradation can disturb proteostasis processes, leading to pathological protein aggregation and neurodegeneration in PD. In recent years, multiple molecular targets in the modulation of protein translation vital to proteostasis and dopaminergic neuron degeneration have been identified. The potential pathophysiological and therapeutic significance of these molecular targets to neurodegeneration in PD is highlighted.
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Affiliation(s)
- Zhi Dong Zhou
- 1Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore.,3Signature Research Program in Neuroscience and Behavioural Disorders, Duke-NUS Medical School Singapore, 8 College Road, Singapore, Singapore
| | - Thevapriya Selvaratnam
- 1Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore
| | - Ji Chao Tristan Lee
- 1Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore
| | - Yin Xia Chao
- 1Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore
| | - Eng-King Tan
- 1Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore.,2Department of Neurology, Singapore General Hospital, Outram Road, Singapore, 169608 Singapore.,3Signature Research Program in Neuroscience and Behavioural Disorders, Duke-NUS Medical School Singapore, 8 College Road, Singapore, Singapore
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16
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Sharma G, Raheja H, Das S. Hepatitis C virus: Enslavement of host factors. IUBMB Life 2018; 70:41-49. [PMID: 29281185 DOI: 10.1002/iub.1702] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 11/20/2017] [Accepted: 11/28/2017] [Indexed: 12/11/2022]
Abstract
Hepatitis C virus (HCV) has infected over 170 million people world-wide. This infection causes severe liver damage that can progress to hepatocellular carcinoma leading to death of the infected patients. Development of a cell culture model system for the study of HCV infection in the recent past has helped the researchers world-wide to understand the biology of this virus. Studies over the past decade have revealed the tricks played by the virus to sustain itself, for as long as 40 years, in the host setup without being eliminated by the immune system. Today we understand that the host organelles and different cellular proteins are affected during HCV infection. This cytoplasmic virus has all the cellular organelles at its disposal to successfully replicate, from ribosomes and intracellular membranous structures to the nucleus. It modulates these organelles at both the structural and the functional levels. The vast knowledge about the viral genome and viral proteins has also helped in the development of drugs against the virus. Despite the achieved success rate to cure the infected patients, we struggle to eliminate the cases of recurrence and the non-responders. Such cases might emerge owing to the property of the viral genome to accumulate mutations during its succeeding replication cycles which favours its survival. The current situation calls an urgent need for alternate therapeutic strategies to counter this major problem of human health. © 2017 IUBMB Life, 70(1):41-49, 2018.
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Affiliation(s)
- Geetika Sharma
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, Karnataka, India
| | - Harsha Raheja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, Karnataka, India
| | - Saumitra Das
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, Karnataka, India
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17
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Hepatitis C Virus Modulates Solute carrier family 3 member 2 for Viral Propagation. Sci Rep 2018; 8:15486. [PMID: 30341327 PMCID: PMC6195511 DOI: 10.1038/s41598-018-33861-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/04/2018] [Indexed: 12/12/2022] Open
Abstract
Hepatitis C virus (HCV) exploits an extensive network of host proteins to maintain chronic infection. Using RNA-Seq technology, we identified 30 host genes that were differentially expressed in cell culture grown HCV (HCVcc)-infected cells. Of these candidate genes, we selected solute carrier family 3 member 2 (SLC3A2) for further investigation. SLC3A2, also known as CD98hc, is a member of the solute carrier family and encodes a subunit of heterodimeric amino acid transporter. SLC3A2 and LAT1 constitute a heterodimeric transmembrane protein complex that catalyzes amino acid transport. In this study, we showed that HCV upregulated both mRNA and protein expression levels of SLC3A2 and this upregulation occurred through NS3/4A-mediated oxidative stress. HCV also elevated SLC3A2/LAT1 complex level and thus mammalian target of rapamycin complex 1 (mTORC1) signaling was activated. We further showed that L-leucine transport level was significantly increased in Jc1-infected cells as compared with mock-infected cells. Using RNA interference technology, we demonstrated that SLC3A2 was specifically required for the entry step but not for other stages of the HCV life cycle. These data suggest that SLC3A2 plays an important role in regulating HCV entry. Collectively, HCV exploits SLC3A2 for viral propagation and upregulation of SLC3A2 may contribute to HCV-mediated pathogenesis.
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18
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Subramani C, Nair VP, Anang S, Mandal SD, Pareek M, Kaushik N, Srivastava A, Saha S, Shalimar, Nayak B, Ranjith-Kumar CT, Surjit M. Host-Virus Protein Interaction Network Reveals the Involvement of Multiple Host Processes in the Life Cycle of Hepatitis E Virus. mSystems 2018; 3:e00135-17. [PMID: 29404423 PMCID: PMC5781259 DOI: 10.1128/msystems.00135-17] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 12/27/2017] [Indexed: 02/07/2023] Open
Abstract
Comprehensive knowledge of host-pathogen interactions is central to understand the life cycle of a pathogen and devise specific therapeutic strategies. Protein-protein interactions (PPIs) are key mediators of host-pathogen interactions. Hepatitis E virus (HEV) is a major cause of viral hepatitis in humans. Recent reports also demonstrate its extrahepatic manifestations in the brain. Toward understanding the molecular details of HEV life cycle, we screened human liver and fetal brain cDNA libraries to identify the host interaction partners of proteins encoded by genotype 1 HEV and constructed the virus-host PPI network. Analysis of the network indicated a role of HEV proteins in modulating multiple host biological processes such as stress and immune responses, the ubiquitin-proteasome system, energy and iron metabolism, and protein translation. Further investigations revealed the presence of multiple host translation regulatory factors in the viral translation/replication complex. Depletion of host translation factors such as eIF4A2, eIF3A, and RACK1 significantly reduced the viral replication, whereas eIF2AK4 depletion had no effect. These findings highlight the ingenuity of the pathogen in manipulating the host machinery to its own benefit, a clear understanding of which is essential for the identification of strategic targets and development of specific antivirals against HEV. IMPORTANCE Hepatitis E virus (HEV) is a pathogen that is transmitted by the fecal-oral route. Owing to the lack of an efficient laboratory model, the life cycle of the virus is poorly understood. During the course of infection, interactions between the viral and host proteins play essential roles, a clear understanding of which is essential to decode the life cycle of the virus. In this study, we identified the direct host interaction partners of all HEV proteins and generated a PPI network. Our functional analysis of the HEV-human PPI network reveals a role of HEV proteins in modulating multiple host biological processes such as stress and immune responses, the ubiquitin-proteasome system, energy and iron metabolism, and protein translation. Further investigations revealed an essential role of several host factors in HEV replication. Collectively, the results from our study provide a vast resource of PPI data from HEV and its human host and identify the molecular components of the viral translation/replication machinery.
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Affiliation(s)
- Chandru Subramani
- Virology Laboratory, Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, India
| | - Vidya P. Nair
- Virology Laboratory, Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, India
| | - Saumya Anang
- Virology Laboratory, Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, India
| | | | - Madhu Pareek
- Virology Laboratory, Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, India
| | - Nidhi Kaushik
- Virology Laboratory, Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, India
| | - Akriti Srivastava
- Virology Laboratory, Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, India
| | - Sudipto Saha
- Bioinformatics Centre, Bose Institute, Kolkata, West Bengal, India
| | - Shalimar
- Department of Gastroenterology, All India Institute of Medical Sciences, Gautam Nagar, Ansari Nagar East, New Delhi, Delhi, India
| | - Baibaswata Nayak
- Department of Gastroenterology, All India Institute of Medical Sciences, Gautam Nagar, Ansari Nagar East, New Delhi, Delhi, India
| | - C. T. Ranjith-Kumar
- Virology Laboratory, Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, India
| | - Milan Surjit
- Virology Laboratory, Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, India
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19
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Golob-Schwarzl N, Krassnig S, Toeglhofer AM, Park YN, Gogg-Kamerer M, Vierlinger K, Schröder F, Rhee H, Schicho R, Fickert P, Haybaeck J. New liver cancer biomarkers: PI3K/AKT/mTOR pathway members and eukaryotic translation initiation factors. Eur J Cancer 2017; 83:56-70. [PMID: 28715695 DOI: 10.1016/j.ejca.2017.06.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 06/01/2017] [Indexed: 12/14/2022]
Abstract
Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. The initiation of protein translation is an important rate-limiting step in eukaryotes and is crucial in many viral infections. Eukaryotic translation initiation factors (eIFs) are involved in the initiation step of protein translation and are linked to the phosphatidylinositol-3-kinases PI3K/AKT/mTOR pathway. Therefore we aimed to investigate a potential role of eIFs in HCC. We herein report on the immunohistochemical expression of the various eIF subunits in 235 cases of virus-related human HCC. Additionally, we used immunoblot analysis to investigate the expression of virus-related HCC and non-virus-related HCC in comparison to controls. Mammalian target of rapamycin (or mechanistic target of rapamycin as it is known now (mTOR) and activated mTOR were significantly increased in chronic hepatitis C (HCV)-associated HCC, in HCC without a viral background, in alcoholic liver disease and Wilson disease. pPTEN, phosphatase and tensin homologue (PTEN) and pAKT showed a significant increase in HBV- and HCV-associated HCC, chronic hepatitis B, HCC without a viral background, alcoholic steatohepatitis (ASH) and Wilson disease. Phosphorylated (p)-eIF2α, eIF2α, eiF3B, eIF3D, eIF3J, p-eIF4B, eIF4G and eIF6 were upregulated in HCV-associated HCC. eIF2α, p-eIF4B, eIF5 and various eIF3 subunits were significantly increased in chronic hepatitis B (HBV)-associated HCC. HCC without viral background displayed a significant increase for the eIF subunits p-2α, 3C, 3I, 4E and 4G. We noticed engraved differences in the expression pattern between chronic hepatitis B and C, HBV- and HCV-associated HCC and non-virus-related HCC.
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Affiliation(s)
- Nicole Golob-Schwarzl
- Department of Pathology, Medical University of Graz, Austria; Center for Biomarker Research in Medicine, Graz, Austria
| | | | | | - Young Nyun Park
- Department of Pathology, Yonsei University, College of Medicine, Seoul, South Korea
| | | | | | | | - Hyungjn Rhee
- Department of Pathology, Yonsei University, University College of Medicine, Seoul, South Korea
| | - Rudolf Schicho
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Austria
| | - Peter Fickert
- Division of Gastroenterology and Hepatology, Medical University of Graz, Austria
| | - Johannes Haybaeck
- Department of Pathology, Medical University of Graz, Austria; Center for Biomarker Research in Medicine, Graz, Austria; Department of Pathology, Otto-von-Guericke-University Magdeburg, Germany.
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20
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Hepatitis C virus core protein targets 4E-BP1 expression and phosphorylation and potentiates Myc-induced liver carcinogenesis in transgenic mice. Oncotarget 2017; 8:56228-56242. [PMID: 28915586 PMCID: PMC5593557 DOI: 10.18632/oncotarget.17280] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/27/2017] [Indexed: 12/23/2022] Open
Abstract
Hepatitis C virus (HCV) is a leading cause of liver diseases including the development of hepatocellular carcinoma (HCC). Particularly, core protein has been involved in HCV-related liver pathologies. However, the impact of HCV core on signaling pathways supporting the genesis of HCC remains largely elusive. To decipher the host cell signaling pathways involved in the oncogenic potential of HCV core, a global quantitative phosphoproteomic approach was carried out. This study shed light on novel differentially phosphorylated proteins, in particular several components involved in translation. Among the eukaryotic initiation factors that govern the translational machinery, 4E-BP1 represents a master regulator of protein synthesis that is associated with the development and progression of cancers due to its ability to increase protein expression of oncogenic pathways. Enhanced levels of 4E-BP1 in non-modified and phosphorylated forms were validated in human hepatoma cells and in mouse primary hepatocytes expressing HCV core, in the livers of HCV core transgenic mice as well as in HCV-infected human primary hepatocytes. The contribution of HCV core in carcinogenesis and the status of 4E-BP1 expression and phosphorylation were studied in HCV core/Myc double transgenic mice. HCV core increased the levels of 4E-BP1 expression and phosphorylation and significantly accelerated the onset of Myc-induced tumorigenesis in these double transgenic mice. These results reveal a novel function of HCV core in liver carcinogenesis potentiation. They position 4E-BP1 as a tumor-specific target of HCV core and support the involvement of the 4E-BP1/eIF4E axis in hepatocarcinogenesis.
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21
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Functional evaluation of synthetic flavonoids and chalcones for potential antiviral and anticancer properties. Bioorg Med Chem Lett 2017; 27:2350-2356. [PMID: 28442256 DOI: 10.1016/j.bmcl.2017.04.034] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/08/2017] [Accepted: 04/10/2017] [Indexed: 12/18/2022]
Abstract
Flavonoids, stilbenes, and chalcones are plant secondary metabolites that often possess diverse biological activities including anti-inflammatory, anti-cancer, and anti-viral activities. The wide range of bioactivities poses a challenge to identify their targets. Here, we studied a set of synthetically generated flavonoids and chalcones to evaluate for their biological activity, and compared similarly substituted flavonoids and chalcones. Substituted chalcones, but not flavonoids, showed inhibition of viral translation without significantly affecting viral replication in cells infected with hepatitis C virus (HCV). We suggest that the chalcones used in this study inhibit mammalian target of rapamycin (mTOR) pathway by ablating phosphorylation of ribosomal protein 6 (rps6), and also the kinase necessary for phosphorylating rps6 in Huh7.5 cells (pS6K1). In addition, selected chalcones showed inhibition of growth in Ishikawa, MCF7, and MDA-MB-231 cells resulting an IC50 of 1-6µg/mL. When similarly substituted flavonoids were used against the same set of cancer cells, we did not observe any inhibitory effect. Together, we report that chalcones show potential for anti-viral and anti-cancer activities compared to similarly substituted flavonoids.
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22
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Kim JH, Sung PS, Lee EB, Hur W, Park DJ, Shin EC, Windisch MP, Yoon SK. GRIM-19 Restricts HCV Replication by Attenuating Intracellular Lipid Accumulation. Front Microbiol 2017; 8:576. [PMID: 28443075 PMCID: PMC5387058 DOI: 10.3389/fmicb.2017.00576] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 03/20/2017] [Indexed: 12/15/2022] Open
Abstract
Gene-associated with retinoid-interferon-induced mortality 19 (GRIM-19) targets multiple signaling pathways involved in cell death and growth. However, the role of GRIM-19 in the pathogenesis of hepatitis virus infections remains unexplored. Here, we investigated the restrictive effects of GRIM-19 on the replication of hepatitis C virus (HCV). We found that GRIM-19 protein levels were reduced in HCV-infected Huh7 cells and Huh7 cells harboring HCV replicons. Moreover, ectopically expressed GRIM-19 caused a reduction in both intracellular viral RNA levels and secreted viruses in HCVcc-infected cell cultures. The restrictive effect on HCV replication was restored by treatment with siRNA against GRIM-19. Interestingly, GRIM-19 overexpression did not alter the level of phosphorylated STAT3 or its subcellular distribution. Strikingly, forced expression of GRIM-19 attenuated an increase in intracellular lipid droplets after oleic acid (OA) treatment or HCVcc infection. GRIM-19 overexpression abrogated fatty acid-induced upregulation of sterol regulatory element-binding transcription factor-1 (SREBP-1c), resulting in attenuated expression of its target genes such as fatty acid synthase (FAS) and acetyl CoA carboxylase (ACC). Treatment with OA or overexpression of SREBP-1c in GRIM-19-expressing, HCVcc-infected cells restored HCV replication. Our results suggest that GRIM-19 interferes with HCV replication by attenuating intracellular lipid accumulation and therefore is an anti-viral host factor that could be a promising target for HCV treatment.
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Affiliation(s)
- Jung-Hee Kim
- The Catholic University Liver Research Center and WHO Collaborating Center of Viral Hepatitis, The Catholic University of KoreaSeoul, South Korea
| | - Pil S Sung
- Laboratory of Immunology and Infectious Diseases, Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea
| | - Eun B Lee
- The Catholic University Liver Research Center and WHO Collaborating Center of Viral Hepatitis, The Catholic University of KoreaSeoul, South Korea
| | - Wonhee Hur
- The Catholic University Liver Research Center and WHO Collaborating Center of Viral Hepatitis, The Catholic University of KoreaSeoul, South Korea
| | - Dong J Park
- The Catholic University Liver Research Center and WHO Collaborating Center of Viral Hepatitis, The Catholic University of KoreaSeoul, South Korea
| | - Eui-Cheol Shin
- Laboratory of Immunology and Infectious Diseases, Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea
| | - Marc P Windisch
- Hepatitis Research Laboratory, Discovery Biology Department, Institut Pasteur Korea, Seongnam-siGyeonggi-do, South Korea
| | - Seung K Yoon
- The Catholic University Liver Research Center and WHO Collaborating Center of Viral Hepatitis, The Catholic University of KoreaSeoul, South Korea
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Stöhr S, Costa R, Sandmann L, Westhaus S, Pfaender S, Anggakusuma, Dazert E, Meuleman P, Vondran FWR, Manns MP, Steinmann E, von Hahn T, Ciesek S. Host cell mTORC1 is required for HCV RNA replication. Gut 2016; 65:2017-2028. [PMID: 26276683 PMCID: PMC5136730 DOI: 10.1136/gutjnl-2014-308971] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 07/10/2015] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Chronically HCV-infected orthotopic liver transplantation (OLT) recipients appear to have improved outcomes when their immunosuppressive regimen includes a mammalian target of rapamycin (mTOR) inhibitor. The mechanism underlying this observation is unknown. DESIGN We used virological assays to investigate mTOR signalling on the HCV replication cycle. Furthermore, we analysed HCV RNA levels of 42 HCV-positive transplanted patients treated with an mTOR inhibitor as part of their immunosuppressive regimen. RESULTS The mTOR inhibitor rapamycin was found to be a potent inhibitor for HCV RNA replication in Huh-7.5 cells as well as primary human hepatocytes. Half-maximal inhibition was observed at 0.01 µg/mL, a concentration that is in the range of serum levels seen in transplant recipients and does not affect cell proliferation. Early replication cycle steps such as cell entry and RNA translation were not affected. Knockdown of raptor, an essential component of mTORC1, but not rictor, an essential component of mTORC2, inhibited viral RNA replication. In addition, overexpression of raptor led to higher viral RNA replication, demonstrating that mTORC1, but not mTORC2, is required for HCV RNA replication. In 42 HCV-infected liver-transplanted or kidney-transplanted patients who were switched to an mTOR inhibitor, we could verify that mTOR inhibition decreased HCV RNA levels in vivo. CONCLUSIONS Our data identify mTORC1 as a novel HCV replication factor. These findings suggest an underlying mechanism for the observed benefits of mTOR inhibition in HCV-positive OLT recipients and potentiate further investigation of mTOR-containing regimens in HCV-positive recipients of solid organ transplants.
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Affiliation(s)
- Stefanie Stöhr
- Department of Gastroenterology, Hepatology and Endocrinology, Medizinische Hochschule Hannover, Hannover, Germany,German Center for Infection Research (DZIF), Hannover, Germany
| | - Rui Costa
- Department of Gastroenterology, Hepatology and Endocrinology, Medizinische Hochschule Hannover, Hannover, Germany
| | - Lisa Sandmann
- Department of Gastroenterology, Hepatology and Endocrinology, Medizinische Hochschule Hannover, Hannover, Germany,German Center for Infection Research (DZIF), Hannover, Germany
| | - Sandra Westhaus
- Department of Gastroenterology, Hepatology and Endocrinology, Medizinische Hochschule Hannover, Hannover, Germany,German Center for Infection Research (DZIF), Hannover, Germany,Institute for Molecular Biology, Medizinische Hochschule Hannover, Hannover, Germany
| | - Stephanie Pfaender
- Division of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research; a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Anggakusuma
- Division of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research; a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Eva Dazert
- Cell Growth and Development Biozentrum, Universität Basel, Basel, Switzerland
| | - Philip Meuleman
- Center for Vaccinology, Ghent University, Ghent University Hospital, Ghent, Belgium
| | - Florian W R Vondran
- German Center for Infection Research (DZIF), Hannover, Germany,Department of General, Visceral and Transplantation Surgery, Medizinische Hochschule Hannover, Hannover, Germany
| | - Michael P Manns
- Department of Gastroenterology, Hepatology and Endocrinology, Medizinische Hochschule Hannover, Hannover, Germany,German Center for Infection Research (DZIF), Hannover, Germany
| | - Eike Steinmann
- Division of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research; a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Thomas von Hahn
- Department of Gastroenterology, Hepatology and Endocrinology, Medizinische Hochschule Hannover, Hannover, Germany,German Center for Infection Research (DZIF), Hannover, Germany,Institute for Molecular Biology, Medizinische Hochschule Hannover, Hannover, Germany
| | - Sandra Ciesek
- Department of Gastroenterology, Hepatology and Endocrinology, Medizinische Hochschule Hannover, Hannover, Germany,German Center for Infection Research (DZIF), Hannover, Germany,Integrated Research and TreatmentCentre—Transplantation (IFB-Tx), Hannover, Germany
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Le Sage V, Cinti A, Amorim R, Mouland AJ. Adapting the Stress Response: Viral Subversion of the mTOR Signaling Pathway. Viruses 2016; 8:v8060152. [PMID: 27231932 PMCID: PMC4926172 DOI: 10.3390/v8060152] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 05/16/2016] [Accepted: 05/19/2016] [Indexed: 02/06/2023] Open
Abstract
The mammalian target of rapamycin (mTOR) is a central regulator of gene expression, translation and various metabolic processes. Multiple extracellular (growth factors) and intracellular (energy status) molecular signals as well as a variety of stressors are integrated into the mTOR pathway. Viral infection is a significant stress that can activate, reduce or even suppress the mTOR signaling pathway. Consequently, viruses have evolved a plethora of different mechanisms to attack and co-opt the mTOR pathway in order to make the host cell a hospitable environment for replication. A more comprehensive knowledge of different viral interactions may provide fruitful targets for new antiviral drugs.
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Affiliation(s)
- Valerie Le Sage
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, QC H3T 1E2, Canada.
| | - Alessandro Cinti
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, QC H3T 1E2, Canada.
- Department of Medicine, McGill University, Montréal, QC H3A 0G4, Canada.
| | - Raquel Amorim
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, QC H3T 1E2, Canada.
- Department of Medicine, McGill University, Montréal, QC H3A 0G4, Canada.
| | - Andrew J Mouland
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, QC H3T 1E2, Canada.
- Department of Medicine, McGill University, Montréal, QC H3A 0G4, Canada.
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Vedagiri D, Lashkari HV, Mangani AS, Kumar JM, Jose J, Thatipalli AR, Harshan KH. An Atypical System for Studying Epithelial-Mesenchymal Transition in Hepatocellular Carcinoma. Sci Rep 2016; 6:26282. [PMID: 27197891 PMCID: PMC4873837 DOI: 10.1038/srep26282] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 04/27/2016] [Indexed: 01/05/2023] Open
Abstract
Intrahepatic and extrahepatic metastases are frequently detected in hepatocellular carcinoma (HCC). Epithelial-mesenchymal transition (EMT) is believed to drive metastasis. There are not many well-established model systems to study EMT in HCC. Here we identified an atypical EMT while characterizing a population of mesenchymal cells in Huh7.5 hepatoma cell cultures. Cells with distinct morphology appeared during geneticin treatment of Huh7.5 cultures. Molecular characterization of geneticin resistant Huh7.5M cells confirmed EMT. Huh7.5M cells expressed cancer stem cell markers. p38MAPK and ERK1/2 were substantially activated in Huh7.5M cells. Their Inhibition elevated E-Cadherin expression with concerted suppression of Vimentin and anchorage independent growth in Huh7.5M cells. TGFβ could not induce EMT in Huh7.5 cultures, but enriched mesenchymal populations, similar to geneticin. Huh7.5M cells formed more aggressive solid tumors, primarily comprising cells with epithelial morphology, in nude mice. Canonical EMT-TFs did not participate in this atypical EMT, indicating that the established canonical EMT-TFs do not drive every EMT and there is a dire need to identify additional factors. The system that we characterized is a unique model to study EMT, MET and biphasic TGFβ signaling in HCC and offers considerable potential to facilitate more insightful studies on deeper questions in tumor metastasis.
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Affiliation(s)
- Dhiviya Vedagiri
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, 500007 India
| | | | | | | | - Jedy Jose
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, 500007 India
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26
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Requirement of the eukaryotic translation initiation factor 4F complex in hepatitis E virus replication. Antiviral Res 2015; 124:11-9. [PMID: 26526587 DOI: 10.1016/j.antiviral.2015.10.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 10/15/2015] [Accepted: 10/19/2015] [Indexed: 01/27/2023]
Abstract
Hepatitis E virus (HEV) infection, one of the foremost causes of acute hepatitis, is becoming a health problem of increasing magnitude. As other viruses, HEV exploits elements from host cell biochemistry, but we understand little as to which components of the human hepatocellular machinery are perverted for HEV multiplication. It is, however, known that the eukaryotic translation initiation factors 4F (eIF4F) complex, the key regulator of the mRNA-ribosome recruitment phase of translation initiation, serves as an important component for the translation and replication of many viruses. Here we aim to investigate the role of three subunits of the eIF4F complex: eukaryotic translation initiation factor 4A (eIF4A), eukaryotic translation initiation factor 4G (eIF4G) and eukaryotic translation initiation factor 4E (eIF4E) in HEV replication. We found that efficient replication of HEV requires eIF4A, eIF4G and eIF4E. Consistently, the negative regulatory factors of this complex: programmed cell death 4 (PDCD4) and eIF4E-binding protein 1 (4E-BP1) exert anti-HEV activities, which further illustrates the requirement for eIF4A and eIF4E in supporting HEV replication. Notably, phosphorylation of eIF4E induced by MNK1/2 activation is not involved in HEV replication. Although ribavirin and interferon-α (IFN-α), the most often-used off-label drugs for treating hepatitis E, interact with this complex, their antiviral activities are independent of eIF4E. In contrast, eIF4E silencing provokes enhanced anti-HEV activity of these compounds. Thus, HEV replication requires eIF4F complex and targeting essential elements of this complex provides important clues for the development of novel antiviral therapy against HEV.
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Guo X, Hu H, Chen F, Li Z, Ye S, Cheng S, Zhang M, He Q. iTRAQ-based comparative proteomic analysis of Vero cells infected with virulent and CV777 vaccine strain-like strains of porcine epidemic diarrhea virus. J Proteomics 2015; 130:65-75. [PMID: 26361011 PMCID: PMC7102838 DOI: 10.1016/j.jprot.2015.09.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 08/28/2015] [Accepted: 09/02/2015] [Indexed: 12/24/2022]
Abstract
The re-emerging porcine epidemic diarrhea virus (PEDV) variant related diarrhea has been documented in China since late 2010 and now with global distribution. Currently, a virulent PEDV CH/YNKM-8/2013 and a CV777 vaccine strain-like AH-M have been successfully isolated from the clinical samples. To dissect out the underlying pathogenic mechanism of virulent PEDV and clarify the differences between virulent and CV777 vaccine strain-like PEDV infections, we performed an iTRAQ-based comparative quantitative proteomic study of Vero cells infected with both PEDV strains. A total of 661 and 474 differentially expressed proteins were identified upon virulent and CV777 vaccine strain-like isolates infection, respectively. Ingenuity Pathway Analysis was employed to investigate the canonical pathways and functional networks involved in both PEDV infections. Comprehensive studies have revealed that the PEDV virulent strain suppressed protein synthesis of Vero cells through down-regulating mTOR as well as its downstream targets 4EBP1 and p70S6K activities, which were validated by immunoblotting. In addition, the virulent strain could activate NF-κB pathway more intensively than the CV777 vaccine strain-like isolate, and elicit stronger inflammatory cascades as well. These data might provide new insights for elucidating the specific pathogenesis of PEDV infection, and pave the way for the development of effective therapeutic strategies. Biological significance Porcine epidemic diarrhea is now worldwide distributed and causing huge economic losses to swine industry. The immunomodulation and pathogenesis between PEDV and host, as well as the difference between virulent and attenuated strains of PEDV infections are still largely unknown. In this study, we presented for the first application of proteomic analysis to compare whole cellular protein alterations induced by virulent and CV777 vaccine strain-like PEDV infections, which might contribute to understand the pathogenesis of PEDV and anti-viral strategy development. Vero cells proteome was individually analyzed upon virulent and attenuated PEDV infections. Many pathways and interactive networks were constructed based on differentially expressed proteins. Virulent PEDV strain suppressed mTOR as well as its downstream targets 4EBP1 and p70S6K activities. Virulent PEDV strain activated NF-κB pathway more intensively than the attenuated isolate.
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Affiliation(s)
- Xiaozhen Guo
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Han Hu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Fangzhou Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhonghua Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Shiyi Ye
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Shuang Cheng
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430070, China
| | - Mengjia Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Qigai He
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
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28
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eIF4E as a control target for viruses. Viruses 2015; 7:739-50. [PMID: 25690796 PMCID: PMC4353914 DOI: 10.3390/v7020739] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/06/2015] [Accepted: 02/11/2015] [Indexed: 01/04/2023] Open
Abstract
Translation is a complex process involving diverse cellular proteins, including the translation initiation factor eIF4E, which has been shown to be a protein that is a point for translational regulation. Viruses require components from the host cell to complete their replication cycles. Various studies show how eIF4E and its regulatory cellular proteins are manipulated during viral infections. Interestingly, viral action mechanisms in eIF4E are diverse and have an impact not only on viral protein synthesis, but also on other aspects that are important for the replication cycle, such as the proliferation of infected cells and stimulation of viral reactivation. This review shows how some viruses use eIF4E and its regulatory proteins for their own benefit in order to spread themselves.
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29
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A unique phosphorylation-dependent eIF4E assembly on 40S ribosomes co-ordinated by hepatitis C virus protein NS5A that activates internal ribosome entry site translation. Biochem J 2014; 462:291-302. [PMID: 24894874 DOI: 10.1042/bj20131530] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We previously reported that the HCV (hepatitis C virus) protein NS5A up-regulated mRNA cap binding eIF4F (eukaryotic initiation factor 4F) complex assembly through mTOR (mechanistic target of rapamycin)-4EBP1 (eIF4E-binding protein 1) pathway and that NS5A (non-structural protein 5A) physically interacted with translation apparatus. In the present study, we demonstrate that NS5A co-ordinates a unique assembly of the cap binding protein eIF4E and 40S ribosome to form a complex that we call ENR (eIF4E-NS5A-ribosome). Recruitment of NS5A and eIF4E to 40S ribosome was confirmed by polysome fractionation, subcellular fractionation and high-salt-wash immunoprecipitation. These observations were also confirmed in HCV-infected cells, validating its biological significance. eIF4E phosphorylation was critical for ENR assembly. 80S ribosome dissociation and RNase integrity assays revealed that, once associated, the ENR complex is stable and RNA interaction is dispensable. Both the N- and C-terminal regions of NS5A domain 1 were indispensable for this assembly and for the NS5A-induced HCV IRES (internal ribosome entry site) activation. The present study demonstrates that NS5A initially associates with phosphorylated eIF4E of eIF4F complex and subsequently recruits it to 40S ribosomes. This is the first time the interaction of viral protein with both eIF4E and ribosomes has been reported. We propose that this assembly would determine the outcome of HCV infection and pathogenesis through regulation of viral and host translation.
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30
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Johnson JC, Martinez O, Honko AN, Hensley LE, Olinger GG, Basler CF. Pyridinyl imidazole inhibitors of p38 MAP kinase impair viral entry and reduce cytokine induction by Zaire ebolavirus in human dendritic cells. Antiviral Res 2014; 107:102-9. [PMID: 24815087 DOI: 10.1016/j.antiviral.2014.04.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 04/23/2014] [Accepted: 04/25/2014] [Indexed: 01/03/2023]
Abstract
Antigen presenting cells (APCs), including macrophages and dendritic cells, are early and sustained targets of Ebola virus (EBOV) infection in vivo. Because EBOV activates mitogen-activated protein kinase (MAPK) signaling upon infection of APCs, we evaluated the effect of pyridinyl imidazole inhibitors of p38 MAPK on EBOV infection of human APCs and EBOV mediated cytokine production from human DCs. The p38 MAPK inhibitors reduced viral replication in PMA-differentiated macrophage-like human THP-1 cells with an IC50 of 4.73μM (SB202190), 8.26μM (p38kinhIII) and 8.21μM (SB203580) and primary human monocyte-derived dendritic cells (MDDCs) with an IC50 of 2.67μM (SB202190). Furthermore, cytokine production from EBOV-treated MDDCs was inhibited in a dose-dependent manner. A control pyridinyl imidazole compound failed to inhibit either EBOV infection or cytokine induction. Using an established EBOV virus-like particle (VLP) entry assay, we demonstrate that inhibitor pretreatment blocked VLP entry suggesting that the inhibitors blocked infection and replication at least in part by blocking EBOV entry. Taken together, our results indicate that pyridinyl imidazole p38 MAPK inhibitors may serve as leads for the development of therapeutics to treat EBOV infection.
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Affiliation(s)
- Joshua C Johnson
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Ft. Detrick, MD 21702, United States
| | - Osvaldo Martinez
- Dept. of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Anna N Honko
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Ft. Detrick, MD 21702, United States
| | - Lisa E Hensley
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Ft. Detrick, MD 21702, United States
| | - Gene G Olinger
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Ft. Detrick, MD 21702, United States
| | - Christopher F Basler
- Dept. of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
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Hepatitis C virus infection induces inflammatory cytokines and chemokines mediated by the cross talk between hepatocytes and stellate cells. J Virol 2013; 87:8169-78. [PMID: 23678168 DOI: 10.1128/jvi.00974-13] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Inflammatory cytokines and chemokines play important roles in inflammation during viral infection. Hepatitis C virus (HCV) is a hepatotropic RNA virus that is closely associated with chronic liver inflammation, fibrosis, and hepatocellular carcinoma. During the progression of HCV-related diseases, hepatic stellate cells (HSCs) contribute to the inflammatory response triggered by HCV infection. However, the underlying molecular mechanisms that mediate HSC-induced chronic inflammation during HCV infection are not fully understood. By coculturing HSCs with HCV-infected hepatocytes in vitro, we found that HSCs stimulated HCV-infected hepatocytes, leading to the expression of proinflammatory cytokines and chemokines such as interleukin-6 (IL-6), IL-8, macrophage inflammatory protein 1α (MIP-1α), and MIP-1β. Moreover, we found that this effect was mediated by IL-1α, which was secreted by HSCs. HCV infection enhanced production of CCAAT/enhancer binding protein (C/EBP) β mRNA, and HSC-dependent IL-1α production contributed to the stimulation of C/EBPβ target cytokines and chemokines in HCV-infected hepatocytes. Consistent with this result, knockdown of mRNA for C/EBPβ in HCV-infected hepatocytes resulted in decreased production of cytokines and chemokines after the addition of HSC conditioned medium. Induction of cytokines and chemokines in hepatocytes by the HSC conditioned medium required a yet to be identified postentry event during productive HCV infection. The cross talk between HSCs and HCV-infected hepatocytes is a key feature of inflammation-mediated, HCV-related diseases.
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Abstract
In the model of Huh-7.5.1 hepatocyte cells infected by the JFH1 hepatitis C virus (HCV) strain, transcriptomic and proteomic studies have revealed modulations of pathways governing mainly apoptosis and cell cycling. Differences between transcriptomic and proteomic studies pointed to regulations occurring at the posttranscriptional level, including the control of mRNA translation. In this study, we investigated at the genome-wide level the translational regulation occurring during HCV infection. Sucrose gradient ultracentrifugation followed by microarray analysis was used to identify translationally regulated mRNAs (mRNAs associated with ribosomes) from JFH1-infected and uninfected Huh-7.5.1 cells. Translationally regulated mRNAs were found to correspond to genes enriched in specific pathways, including vesicular transport and posttranscriptional regulation. Interestingly, the strongest translational regulation was found for mRNAs encoding proteins involved in pre-mRNA splicing, mRNA translation, and protein folding. Strikingly, these pathways were not previously identified, through transcriptomic studies, as being modulated following HCV infection. Importantly, the observed changes in host mRNA translation were directly due to HCV replication rather than to HCV entry, since they were not observed in JFH1-infected Huh-7.5.1 cells treated with a potent HCV NS3 protease inhibitor. Overall, this study highlights the need to consider, beyond transcriptomic or proteomic studies, the modulation of host mRNA translation as an important aspect of HCV infection.
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Interferon alpha and ribavirin collaboratively regulate p38 mitogen-activated protein kinase signaling in hepatoma cells. Cytokine 2013; 61:801-7. [PMID: 23410505 DOI: 10.1016/j.cyto.2013.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 12/16/2012] [Accepted: 01/04/2013] [Indexed: 01/03/2023]
Abstract
Signaling events triggered by interferon alpha (IFN-α) and ribavirin are involved in anti-hepatitis C virus (HCV) action. The p38 mitogen-activated protein kinase (MAPK) pathway plays an important role in HCV pathogenesis. Effects of IFN-α and ribavirin on p38 MAPK signaling were investigated in human hepatoma cells. Type I IFN receptor 2 (IFNAR2) mediated IFN-α-induced p38 MAPK phosphorylation. Also, p38 MAPK phosphorylation was enhanced by ribavirin. Treatment for 48 h with a combination of IFN-α and ribavirin increased p38 MAPK phosphorylation, whereas the treatment for 72 h reduced p38 MAPK phosphorylation. Cell culture-derived HCV (HCVcc) infection dramatically increased p38 MAPK phosphorylation and such phosphorylation was inhibited by IFN-α or ribavirin. Moreover, siRNA-mediated knockdown of p38 MAPK resulted in enhancement of ribavirin-dependent HCV RNA replication. These results suggest that regulation of p38 MAPK signaling by IFN-α and ribavirin might contribute to anti-HCV action.
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Huang H, Kang R, Wang J, Luo G, Yang W, Zhao Z. Hepatitis C virus inhibits AKT-tuberous sclerosis complex (TSC), the mechanistic target of rapamycin (MTOR) pathway, through endoplasmic reticulum stress to induce autophagy. Autophagy 2012; 9:175-95. [PMID: 23169238 DOI: 10.4161/auto.22791] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Hepatitis C virus (HCV) is able to induce autophagy via endoplasmic reticulum (ER) stress, but the exact molecular signaling pathway is not well understood. We found that the activity of the mechanistic target of rapamycin complex 1 (MTORC1) was inhibited in Huh7 cells either harboring HCV-N (genotype 1b) full-genomic replicon or infected with JFH1 (genotype 2a) virus, which led to the activation of UNC-51-like kinase 1 (ULK1) and thus to autophagy. We then analyzed activity upstream of MTORC1, and found that both protein kinase, AMP-activated, α (PRKAA, including PRKAA1 and PRKAA2, also known as AMP-activated protein kinase, AMPKα) and AKT (refers to pan AKT, including three isoforms of AKT1-3, also known as protein kinase B, PKB) were inhibited by HCV infection. The inhibition of the AKT-TSC-MTORC1 pathway contributed to upregulating autophagy, but inhibition of PRKAA downregulated autophagy. The net effect on autophagy was from AKT, which overrode the inhibition effect from PRKAA. It was further found that HCV-induced ER stress was responsible for the inhibition of the AKT pathway. Metformin, a PRKAA agonist, inhibited HCV replication not only by activating PRKAA as previously reported, but also by activating AKT independently of the autophagy pathway. Taken together, our data suggested HCV inhibited the AKT-TSC-MTORC1 pathway via ER stress, resulting in autophagy, which may contribute to the establishment of the HCV-induced autophagy.
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Affiliation(s)
- He Huang
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
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Modulation of autophagy-like processes by tumor viruses. Cells 2012; 1:204-47. [PMID: 24710474 PMCID: PMC3901111 DOI: 10.3390/cells1030204] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 06/13/2012] [Accepted: 06/14/2012] [Indexed: 02/07/2023] Open
Abstract
Autophagy is an intracellular degradation pathway for long-lived proteins and organelles. This process is activated above basal levels upon cell intrinsic or environmental stress and dysregulation of autophagy has been linked to various human diseases, including those caused by viral infection. Many viruses have evolved strategies to directly interfere with autophagy, presumably to facilitate their replication or to escape immune detection. However, in some cases, modulation of autophagy appears to be a consequence of the virus disturbing the cell’s metabolic signaling networks. Here, we summarize recent advances in research at the interface of autophagy and viral infection, paying special attention to strategies that human tumor viruses have evolved.
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