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Yang X, Tian S, Min Z, Garbarino E, Ma J, Jia J, Tang H, Li L. AMPK restricts HHV-6A replication by inhibiting glycolysis and mTOR signaling. Virology 2024; 595:110080. [PMID: 38631099 DOI: 10.1016/j.virol.2024.110080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 03/22/2024] [Accepted: 04/03/2024] [Indexed: 04/19/2024]
Abstract
AMP-activated protein kinase (AMPK) is a cellular energy sensor regulating metabolic homeostasis. In this study, we investigated the role of AMPK in response to human herpesvirus 6A (HHV-6A) infection. We show that HHV-6A infection significantly downregulates the active phosphorylated state of AMPK in infected T cells. Pharmacological activation of AMPK highly attenuated HHV-6A propagation. Mechanistically, we found that the activation of AMPK by AICAR blocked HHV-6-induced glycolysis by inhibiting glucose metabolism and lactate secretion, as well as decreasing expressions of key glucose transporters and glycolytic enzymes. In addition, mTOR signaling has been inactivated in HHV-6A infected T cells by AICAR treatment. We also showed that HHV-6A infection of human umbilical cord blood mononuclear cells (CBMCs) reduced AMPK activity whereas the activation of AMPK by metformin drastically reduced HHV-6A DNA replication and virions production. Taken together, this study demonstrates that AMPK is a promising antiviral therapeutic target against HHV-6A infection.
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Affiliation(s)
- Xiaodi Yang
- Department of Medical Genetics, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China
| | - Siyu Tian
- Department of Medical Genetics, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China
| | - Zhujiang Min
- Department of Medical Genetics, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China
| | - Emanuela Garbarino
- Department of Immunology, National Vaccine Innovation Platform, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China
| | - Jingjing Ma
- Department of Immunology, National Vaccine Innovation Platform, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China
| | - Junli Jia
- Department of Immunology, National Vaccine Innovation Platform, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China
| | - Huamin Tang
- Department of Immunology, National Vaccine Innovation Platform, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China; The Laboratory Center for Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China.
| | - Lingyun Li
- Department of Medical Genetics, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China.
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2
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Krause M, Samolej J, Yakimovich A, Kriston-Vizi J, Huttunen M, Lara-Reyna S, Frickel EM, Mercer J. Vaccinia virus subverts xenophagy through phosphorylation and nuclear targeting of p62. J Cell Biol 2024; 223:e202104129. [PMID: 38709216 PMCID: PMC11076808 DOI: 10.1083/jcb.202104129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 11/13/2023] [Accepted: 02/12/2024] [Indexed: 05/07/2024] Open
Abstract
Autophagy is an essential degradation program required for cell homeostasis. Among its functions is the engulfment and destruction of cytosolic pathogens, termed xenophagy. Not surprisingly, many pathogens use various strategies to circumvent or co-opt autophagic degradation. For poxviruses, it is known that infection activates autophagy, which however is not required for successful replication. Even though these complex viruses replicate exclusively in the cytoplasm, autophagy-mediated control of poxvirus infection has not been extensively explored. Using the prototypic poxvirus, vaccinia virus (VACV), we show that overexpression of the xenophagy receptors p62, NDP52, and Tax1Bp1 restricts poxvirus infection. While NDP52 and Tax1Bp1 were degraded, p62 initially targeted cytoplasmic virions before being shunted to the nucleus. Nuclear translocation of p62 was dependent upon p62 NLS2 and correlated with VACV kinase mediated phosphorylation of p62 T269/S272. This suggests that VACV targets p62 during the early stages of infection to avoid destruction and further implies that poxviruses exhibit multi-layered control of autophagy to facilitate cytoplasmic replication.
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Affiliation(s)
- Melanie Krause
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Jerzy Samolej
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Artur Yakimovich
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Janos Kriston-Vizi
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Moona Huttunen
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Samuel Lara-Reyna
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Eva-Maria Frickel
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Jason Mercer
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
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3
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Chakravarty S, Subramanian G, Popli S, Veleeparambil M, Fan S, Chakravarti R, Chattopadhyay S. Interferon-stimulated gene TDRD7 interacts with AMPK and inhibits its activation to suppress viral replication and pathogenesis. mBio 2023; 14:e0061123. [PMID: 37712680 PMCID: PMC10653931 DOI: 10.1128/mbio.00611-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 07/24/2023] [Indexed: 09/16/2023] Open
Abstract
IMPORTANCE Virus infection triggers induction of interferon (IFN)-stimulated genes (ISGs), which ironically inhibit viruses themselves. We identified Tudor domain-containing 7 (TDRD7) as a novel antiviral ISG, which inhibits viral replication by interfering with autophagy pathway. Here, we present a molecular basis for autophagy inhibitory function of TDRD7. TDRD7 interacted with adenosine monophosphate (AMP)-activated protein kinase (AMPK), the kinase that initiates autophagy, to inhibit its activation. We identified domains required for the interaction; deleting AMPK-interacting domain blocked antiAMPK and antiviral activities of TDRD7. We used primary cells and mice to evaluate the TDRD7-AMPK antiviral pathway. TDRD7-deficient primary mouse cells exhibited enhanced AMPK activation and viral replication. Finally, TDRD7 knockout mice showed increased susceptibility to respiratory virus infection. Therefore, our study revealed a new antiviral pathway of IFN and its contribution to host response. Our results have therapeutic potential; a TDRD7-derived peptide may be an effective AMPK inhibitor with application as antiviral agent.
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Affiliation(s)
- Sukanya Chakravarty
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Gayatri Subramanian
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Sonam Popli
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Manoj Veleeparambil
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Shumin Fan
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Ritu Chakravarti
- Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Saurabh Chattopadhyay
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
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4
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Tang X, Xie Y, Li G, Niyazbekova Z, Li S, Chang J, Chen D, Ma W. ORFV entry into host cells via clathrin-mediated endocytosis and macropinocytosis. Vet Microbiol 2023; 284:109831. [PMID: 37480660 DOI: 10.1016/j.vetmic.2023.109831] [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: 04/22/2023] [Revised: 07/10/2023] [Accepted: 07/11/2023] [Indexed: 07/24/2023]
Abstract
Orf virus (ORFV), also known as infectious pustular virus, leads to an acute contagious zoonotic infectious disease. ORFV can directly contact and infect epithelial cells of skin and mucosa, causing damage to tissue cells. So far, the pathway of ORFV entry into cells is unclear. Therefore, finding the internalization pathway of ORFV will help to elucidate the cellular and molecular mechanisms of ORFV infection and invasion, which in turn will provide a certain reference for the prevention and treatment of ORFV. In the present study, chemical inhibitors were used to analyze the mechanism of ORFV entry into target cells. The results showed that the inhibitor of clathrin-mediated endocytosis could inhibit ORFV entry into cells. However, the inhibitor of caveolae-mediated endocytosis cannot inhibit ORFV entry into cells. In addition, inhibition of macropinocytosis pathway also significantly reduced ORFV internalization. Furthermore, the inhibitors of acidification and dynamin also prevented ORFV entry. However, results demonstrated that inhibitors inhibited ORFV entry but did not inhibit ORFV binding. Notably, extracellular trypsin promoted ORFV entry into cells directly, even when the endocytic pathway was inhibited. In conclusion, ORFV enters into its target cells by clathrin-mediated endocytosis and macropinocytosis, while caveolae-dependent endocytosis has little effects on this process. In addition, the entry into target cells by ORFV required an acid environment and the effect of dynamin. Meanwhile, we emphasize that broad-spectrum antiviral inhibitors and extracellular enzyme inhibitors are likely to be effective strategies for the prevention and treatment of ORFV infection.
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Affiliation(s)
- Xidian Tang
- Veterinary Immunology Laboratory, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling 712100, Shaanxi Province, China
| | - Yanfei Xie
- Veterinary Immunology Laboratory, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling 712100, Shaanxi Province, China
| | - Guanhua Li
- Veterinary Immunology Laboratory, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling 712100, Shaanxi Province, China
| | - Zhannur Niyazbekova
- College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling 712100, Shaanxi Province, China
| | - Shaofei Li
- Veterinary Immunology Laboratory, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling 712100, Shaanxi Province, China
| | - Jianjun Chang
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining 810016, Qinghai Province, China; College of Agriculture and Animal Husbandry, Qinghai University, Xining 810016, Qinghai Province, China
| | - Dekun Chen
- Veterinary Immunology Laboratory, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling 712100, Shaanxi Province, China.
| | - Wentao Ma
- Veterinary Immunology Laboratory, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling 712100, Shaanxi Province, China.
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5
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Zhou Y, Wang Q, Ying Q, Zhang X, Chen K, Ye T, Li G. Effects of Oncolytic Vaccinia Viruses Harboring Different Marine Lectins on Hepatocellular Carcinoma Cells. Int J Mol Sci 2023; 24:ijms24043823. [PMID: 36835232 PMCID: PMC9965933 DOI: 10.3390/ijms24043823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 02/10/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
Oncolytic viruses are being developed as novel strategies for cancer therapy. Our previous studies have shown that vaccinia viruses armed with marine lectins improved the antitumor efficacy in diverse cancer types. The objective of this study was to assess the cytotoxic effects of oncoVV harboring Tachypleus tridentatus lectin (oncoVV-TTL), Aphrocallistes vastus lectin (oncoVV-AVL), white-spotted charr lectin (oncoVV-WCL), and Asterina pectinifera lectin (oncoVV-APL) on HCC. Our data revealed that the effects of recombinant viruses on Hep-3B cells were oncoVV-AVL > oncoVV-APL > oncoVV-TTL > oncoVV-WCL; oncoVV-AVL showed stronger cytotoxicity than oncoVV-APL, while oncoVV-TTL/WCL had no effect on cell killing in Huh7 cells, and PLC/PRF/5 cells exhibited sensitivity to oncoVV-AVL/TTL but not to oncoVV-APL/WCL. The cytotoxicity of oncoVV-lectins could be enhanced by apoptosis and replication in a cell-type-dependent manner. Further research revealed that AVL may mediate various pathways, including MAPK, Hippo, PI3K, lipid metabolism, and androgen pathways through AMPK crosstalk, to promote oncoVV replication in HCC in a cell-dependent manner. OncoVV-APL replication could be affected by AMPK/Hippo/lipid metabolism pathways in Hep-3B cells, AMPK/Hippo/PI3K/androgen pathways in Huh7 cells, and AMPK/Hippo pathways in PLC/PRF/5 cells. OncoVV-WCL replication was also multi-mechanistic, which could be affected by AMPK/JNK/lipid metabolism pathways in Hep-3B cells, AMPK/Hippo/androgen pathways in Huh7 cells, and AMPK/JNK/Hippo pathways in PLC/PRF/5 cells. In addition, AMPK and lipid metabolism pathways may play critical roles in oncoVV-TTL replication in Hep-3B cells, and oncoVV-TTL replication in Huh7 cells may depend on AMPK/PI3K/androgen pathways. This study provides evidence for the application of oncolytic vaccinia viruses in hepatocellular carcinoma.
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Affiliation(s)
| | | | | | | | | | - Ting Ye
- Correspondence: (T.Y.); (G.L.)
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Matía A, Lorenzo MM, Romero-Estremera YC, Sánchez-Puig JM, Zaballos A, Blasco R. Identification of β2 microglobulin, the product of B2M gene, as a Host Factor for Vaccinia Virus Infection by Genome-Wide CRISPR genetic screens. PLoS Pathog 2022; 18:e1010800. [PMID: 36574441 PMCID: PMC9829182 DOI: 10.1371/journal.ppat.1010800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 01/09/2023] [Accepted: 12/13/2022] [Indexed: 12/28/2022] Open
Abstract
Genome-wide genetic screens are powerful tools to identify genes that act as host factors of viruses. We have applied this technique to analyze the infection of HeLa cells by Vaccinia virus, in an attempt to find genes necessary for infection. Infection of cell populations harboring single gene inactivations resulted in no surviving cells, suggesting that no single gene knock-out was able to provide complete resistance to Vaccinia virus and thus allow cells to survive infection. In the absence of an absolute infection blockage, we explored if some gene inactivations could provide partial protection leading to a reduced probability of infection. Multiple experiments using modified screening procedures involving replication restricted viruses led to the identification of multiple genes whose inactivation potentially increase resistance to infection and therefore cell survival. As expected, significant gene hits were related to proteins known to act in virus entry, such as ITGB1 and AXL as well as genes belonging to their downstream related pathways. Additionally, we consistently found β2-microglobulin, encoded by the B2M gene, among the screening top hits, a novel finding that was further explored. Inactivation of B2M resulted in 54% and 91% reduced VV infection efficiency in HeLa and HAP1 cell lines respectively. In the absence of B2M, while virus binding to the cells was unaffected, virus internalization and early gene expression were significantly diminished. These results point to β2-microglobulin as a relevant factor in the Vaccinia virus entry process.
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Affiliation(s)
- Alejandro Matía
- Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria–Consejo Superior de Investigaciones Científicas (INIA–CSIC), Madrid, Spain
| | - Maria M. Lorenzo
- Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria–Consejo Superior de Investigaciones Científicas (INIA–CSIC), Madrid, Spain
| | - Yolimar C. Romero-Estremera
- Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria–Consejo Superior de Investigaciones Científicas (INIA–CSIC), Madrid, Spain
| | - Juana M. Sánchez-Puig
- Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria–Consejo Superior de Investigaciones Científicas (INIA–CSIC), Madrid, Spain
| | - Angel Zaballos
- Unidad de Genómica, Centro Nacional de Microbiología-ISCIII, Madrid, Spain
| | - Rafael Blasco
- Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria–Consejo Superior de Investigaciones Científicas (INIA–CSIC), Madrid, Spain
- * E-mail:
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7
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Benoit I, Di Curzio D, Civetta A, Douville RN. Drosophila as a Model for Human Viral Neuroinfections. Cells 2022; 11:cells11172685. [PMID: 36078091 PMCID: PMC9454636 DOI: 10.3390/cells11172685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/21/2022] [Accepted: 08/22/2022] [Indexed: 11/16/2022] Open
Abstract
The study of human neurological infection faces many technical and ethical challenges. While not as common as mammalian models, the use of Drosophila (fruit fly) in the investigation of virus–host dynamics is a powerful research tool. In this review, we focus on the benefits and caveats of using Drosophila as a model for neurological infections and neuroimmunity. Through the examination of in vitro, in vivo and transgenic systems, we highlight select examples to illustrate the use of flies for the study of exogenous and endogenous viruses associated with neurological disease. In each case, phenotypes in Drosophila are compared to those in human conditions. In addition, we discuss antiviral drug screening in flies and how investigating virus–host interactions may lead to novel antiviral drug targets. Together, we highlight standardized and reproducible readouts of fly behaviour, motor function and neurodegeneration that permit an accurate assessment of neurological outcomes for the study of viral infection in fly models. Adoption of Drosophila as a valuable model system for neurological infections has and will continue to guide the discovery of many novel virus–host interactions.
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Affiliation(s)
- Ilena Benoit
- Department of Biology, University of Winnipeg, 599 Portage Avenue, Winnipeg, MB R3B 2G3, Canada
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, 351 Taché Ave, Winnipeg, MB R2H 2A6, Canada
| | - Domenico Di Curzio
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, 351 Taché Ave, Winnipeg, MB R2H 2A6, Canada
| | - Alberto Civetta
- Department of Biology, University of Winnipeg, 599 Portage Avenue, Winnipeg, MB R3B 2G3, Canada
| | - Renée N. Douville
- Department of Biology, University of Winnipeg, 599 Portage Avenue, Winnipeg, MB R3B 2G3, Canada
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, 351 Taché Ave, Winnipeg, MB R2H 2A6, Canada
- Correspondence:
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8
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Abstract
Macropinocytosis is an evolutionarily conserved endocytic pathway that mediates the nonselective acquisition of extracellular material via large endocytic vesicles known as macropinosomes. In addition to other functions, this uptake pathway supports cancer cell metabolism through the uptake of nutrients. Cells harboring oncogene or tumor suppressor mutations are known to display heightened macropinocytosis, which confers to the cancer cells the ability to survive and proliferate despite the nutrient-scarce conditions of the tumor microenvironment. Thus, macropinocytosis is associated with cancer malignancy. Macropinocytic uptake can be induced in cancer cells by different stress stimuli, acting as an adaptive mechanism for the cells to resist stresses in the tumor milieu. Here, we review the cellular stresses that are known to promote macropinocytosis, as well as the underlying molecular mechanisms that drive this process.
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Affiliation(s)
- Guillem Lambies
- Cell and Molecular Biology of Cancer Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Cosimo Commisso
- Cell and Molecular Biology of Cancer Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.
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9
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AMP-activated kinase regulates porcine reproductive and respiratory syndrome virus infection in vitro. Virus Genes 2022; 58:133-142. [DOI: 10.1007/s11262-022-01888-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 02/11/2022] [Indexed: 10/18/2022]
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10
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Fuentes-Zacarías P, Murrieta-Coxca JM, Gutiérrez-Samudio RN, Schmidt A, Schmidt A, Markert UR, Morales-Prieto DM. Pregnancy and pandemics: Interaction of viral surface proteins and placenta cells. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166218. [PMID: 34311080 PMCID: PMC9188292 DOI: 10.1016/j.bbadis.2021.166218] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 07/06/2021] [Accepted: 07/15/2021] [Indexed: 12/18/2022]
Abstract
Throughout history, pandemics of infectious diseases caused by emerging viruses have spread worldwide. Evidence from previous outbreaks demonstrated that pregnant women are at high risk of contracting the diseases and suffering from adverse outcomes. However, while some viruses can cause major health complications for the mother and her fetus, others do not appear to affect pregnancy. Viral surface proteins bind to specific receptors on the cellular membrane of host cells and begin therewith the infection process. During pregnancy, the molecular features of these proteins may determine specific target cells in the placenta, which may explain the different outcomes. In this review, we display information on Variola, Influenza, Zika and Corona viruses focused on their surface proteins, effects on pregnancy, and possible target placental cells. This will contribute to understanding viral entry during pregnancy, as well as to develop strategies to decrease the incidence of obstetrical problems in current and future infections.
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Affiliation(s)
| | - Jose M Murrieta-Coxca
- Placenta Lab, Department of Obstetrics, Jena University Hospital, 07747 Jena, Germany
| | | | - Astrid Schmidt
- Placenta Lab, Department of Obstetrics, Jena University Hospital, 07747 Jena, Germany
| | - Andre Schmidt
- Placenta Lab, Department of Obstetrics, Jena University Hospital, 07747 Jena, Germany
| | - Udo R Markert
- Placenta Lab, Department of Obstetrics, Jena University Hospital, 07747 Jena, Germany..
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Abstract
Cellular activities are finely regulated by numerous signaling pathways to support specific functions of complex life processes. Viruses are obligate intracellular parasites. Each step of viral replication is ultimately governed by the interaction of a virus with its host cells. Because of the demands of viral replication, the nutritional needs of virus-infected cells differ from those of uninfected cells. To improve their chances of survival and replication, viruses have evolved to commandeer cellular processes, including cell metabolism, augmenting these processes to support their needs. This article summarizes recent findings regarding virus-induced alterations to major cellular metabolic pathways focusing on how viruses modulate various signaling cascades to induce these changes. We begin with a general introduction describing the role played by signaling pathways in cellular metabolism. We then discuss how different viruses target these signaling pathways to reprogram host metabolism to favor the viral needs. We highlight the gaps in understanding metabolism-related virus-host interactions and discuss how studying these changes will enhance our understanding of fundamental processes involved in metabolic regulation. Finally, we discuss the potential to harness these processes to combat viral diseases, as well as other diseases, including metabolic disorders and cancers.
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12
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Aromolaran O, Beder T, Adedeji E, Ajamma Y, Oyelade J, Adebiyi E, Koenig R. Predicting host dependency factors of pathogens in Drosophila melanogaster using machine learning. Comput Struct Biotechnol J 2021; 19:4581-4592. [PMID: 34471501 PMCID: PMC8385402 DOI: 10.1016/j.csbj.2021.08.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/06/2021] [Accepted: 08/06/2021] [Indexed: 11/25/2022] Open
Abstract
Pathogens causing infections, and particularly when invading the host cells, require the host cell machinery for efficient regeneration and proliferation during infection. For their life cycle, host proteins are needed and these Host Dependency Factors (HDF) may serve as therapeutic targets. Several attempts have approached screening for HDF producing large lists of potential HDF with, however, only marginal overlap. To get consistency into the data of these experimental studies, we developed a machine learning pipeline. As a case study, we used publicly available lists of experimentally derived HDF from twelve different screening studies based on gene perturbation in Drosophila melanogaster cells or in vivo upon bacterial or protozoan infection. A total of 50,334 gene features were generated from diverse categories including their functional annotations, topology attributes in protein interaction networks, nucleotide and protein sequence features, homology properties and subcellular localization. Cross-validation revealed an excellent prediction performance. All feature categories contributed to the model. Predicted and experimentally derived HDF showed a good consistency when investigating their common cellular processes and function. Cellular processes and molecular function of these genes were highly enriched in membrane trafficking, particularly in the trans-Golgi network, cell cycle and the Rab GTPase binding family. Using our machine learning approach, we show that HDF in organisms can be predicted with high accuracy evidencing their common investigated characteristics. We elucidated cellular processes which are utilized by invading pathogens during infection. Finally, we provide a list of 208 novel HDF proposed for future experimental studies.
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Affiliation(s)
- Olufemi Aromolaran
- Department of Computer & Information Sciences, Covenant University, Ota, Ogun State, Nigeria
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
| | - Thomas Beder
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
- Institute of Infectious Diseases and Infection Control, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Eunice Adedeji
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
- Department of Biochemistry, Covenant University, Ota, Ogun State, Nigeria
| | - Yvonne Ajamma
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
| | - Jelili Oyelade
- Department of Computer & Information Sciences, Covenant University, Ota, Ogun State, Nigeria
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
| | - Ezekiel Adebiyi
- Department of Computer & Information Sciences, Covenant University, Ota, Ogun State, Nigeria
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
| | - Rainer Koenig
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
- Institute of Infectious Diseases and Infection Control, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
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13
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Bhutta MS, Gallo ES, Borenstein R. Multifaceted Role of AMPK in Viral Infections. Cells 2021; 10:1118. [PMID: 34066434 PMCID: PMC8148118 DOI: 10.3390/cells10051118] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/02/2021] [Accepted: 05/03/2021] [Indexed: 02/06/2023] Open
Abstract
Viral pathogens often exploit host cell regulatory and signaling pathways to ensure an optimal environment for growth and survival. Several studies have suggested that 5'-adenosine monophosphate-activated protein kinase (AMPK), an intracellular serine/threonine kinase, plays a significant role in the modulation of infection. Traditionally, AMPK is a key energy regulator of cell growth and proliferation, host autophagy, stress responses, metabolic reprogramming, mitochondrial homeostasis, fatty acid β-oxidation and host immune function. In this review, we highlight the modulation of host AMPK by various viruses under physiological conditions. These intracellular pathogens trigger metabolic changes altering AMPK signaling activity that then facilitates or inhibits viral replication. Considering the COVID-19 pandemic, understanding the regulation of AMPK signaling following infection can shed light on the development of more effective therapeutic strategies against viral infectious diseases.
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Affiliation(s)
- Maimoona Shahid Bhutta
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA 23507, USA;
| | - Elisa S. Gallo
- Board-Certified Dermatologist and Independent Researcher, Norfolk, VA 23507, USA;
| | - Ronen Borenstein
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA 23507, USA;
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Possible roles of AMPK and macropinocytosis in the defense responses against Δ 9-THC toxicity on HL-1 cardiomyocytes. Toxicol Rep 2021; 8:980-987. [PMID: 34026562 PMCID: PMC8131391 DOI: 10.1016/j.toxrep.2021.04.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/19/2021] [Accepted: 04/27/2021] [Indexed: 12/17/2022] Open
Abstract
Cannabinoids are some of the most popular recreationally used illicit drugs, and are frequently consumed along with alcoholic beverages. Although the whole body effects of cannabinoids depend largely on their effects on the central nerve system, cannabinoids could harm the heart directly, due to the presence of the endocannabinoid system including cannabinoid receptor1 and 2 (CB-R1 and CB-R2) in the heart. The aim of this study is to examine the mechanism of direct cardiotoxicity of Δ9-tetrahydrocannabinol (Δ9-THC), the main psychoactive ingredient of cannabis. For this purpose, HL-1 murine atrial cardiac muscle cells were treated with 10 or 30 μM Δ9-THC, along with 100 mM ethanol to examine the possible synergistic effects of Δ9-THC and ethanol. Transcriptome analysis showed upregulation of the genes involved in the unfolded protein response (UPR), including Bip, CHOP, ATF4 and ATF6, in cells treated with Δ9-THC. Immunoblot analysis showed caspase3 activation, indicating apoptosis caused by ER stress in Δ9-THC-treated cells. Microscopic analysis showed that Δ9-THC enhances macropinocytosis, a process involved in the uptake of extracellular fluids including nutrients. Moreover Δ9-THC seemed to activate AMPK, a sensor of intracellular energy status and an activator of macropinocytosis. Finally, we found that compound C (AMPK inhibitor) aggravated cell death by Δ9-THC while AICAR (AMPK activator) ameliorated it. Collectively, these results indicate that the activation of AMPK is necessary for the survival of HL-1 cells against Δ9-THC toxicity. Macropinocytosis might serve as one of the survival pathways downstream of AMPK.
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15
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Peng C, Zhou Y, Cao S, Pant A, Campos Guerrero ML, McDonald P, Roy A, Yang Z. Identification of Vaccinia Virus Inhibitors and Cellular Functions Necessary for Efficient Viral Replication by Screening Bioactives and FDA-Approved Drugs. Vaccines (Basel) 2020; 8:vaccines8030401. [PMID: 32708182 PMCID: PMC7564539 DOI: 10.3390/vaccines8030401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/12/2020] [Accepted: 07/16/2020] [Indexed: 02/07/2023] Open
Abstract
Four decades after the eradication of smallpox, poxviruses continue to threaten the health of humans and other animals. Vaccinia virus (VACV) was used as the vaccine that successfully eradicated smallpox and is a prototypic member of the poxvirus family. Many cellular pathways play critical roles in productive poxvirus replication. These pathways provide opportunities to expand the arsenal of poxvirus antiviral development by targeting the cellular functions required for efficient poxvirus replication. In this study, we developed and optimized a secreted Gaussia luciferase-based, simplified assay procedure suitable for high throughput screening. Using this procedure, we screened a customized compound library that contained over 3200 bioactives and FDA (Food and Drug Administration)-approved chemicals, most having known cellular targets, for their inhibitory effects on VACV replication. We identified over 140 compounds that suppressed VACV replication. Many of these hits target cellular pathways previously reported to be required for efficient VACV replication, validating the effectiveness of our screening. Importantly, we also identified hits that target cellular functions with previously unknown roles in the VACV replication cycle. Among those in the latter category, we verified the antiviral role of several compounds targeting the janus kinase/signal transducer and activator of transcription-3 (JAK/STAT3) signaling pathway by showing that STAT3 inhibitors reduced VACV replication. Our findings identify pathways that are candidates for use in the prevention and treatment of poxvirus infections and additionally provide a foundation to investigate diverse cellular pathways for their roles in poxvirus replications.
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Affiliation(s)
- Chen Peng
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA; (C.P.); (Y.Z.); (S.C.); (A.P.); (M.L.C.G.)
| | - Yanan Zhou
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA; (C.P.); (Y.Z.); (S.C.); (A.P.); (M.L.C.G.)
| | - Shuai Cao
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA; (C.P.); (Y.Z.); (S.C.); (A.P.); (M.L.C.G.)
| | - Anil Pant
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA; (C.P.); (Y.Z.); (S.C.); (A.P.); (M.L.C.G.)
| | - Marlene L. Campos Guerrero
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA; (C.P.); (Y.Z.); (S.C.); (A.P.); (M.L.C.G.)
| | - Peter McDonald
- High Throughput Screening Laboratory, University of Kansas, Lawrence, KS 66045, USA; (P.M.); (A.R.)
| | - Anuradha Roy
- High Throughput Screening Laboratory, University of Kansas, Lawrence, KS 66045, USA; (P.M.); (A.R.)
| | - Zhilong Yang
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA; (C.P.); (Y.Z.); (S.C.); (A.P.); (M.L.C.G.)
- Correspondence:
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16
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Kami D, Gojo S. From Cell Entry to Engraftment of Exogenous Mitochondria. Int J Mol Sci 2020; 21:ijms21144995. [PMID: 32679802 PMCID: PMC7404190 DOI: 10.3390/ijms21144995] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/07/2020] [Accepted: 07/13/2020] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial transfer has been recognized to play a role in a variety of processes, ranging from fertilization to cancer and neurodegenerative diseases as well as mammalian horizontal gene transfer. It is achieved through either exogeneous or intercellular mitochondrial transfer. From the viewpoint of evolution, exogeneous mitochondrial transfer is quite akin to the initial process of symbiosis between α-protobacterium and archaea, although the progeny have developed more sophisticated machinery to engulf environmental materials, including nutrients, bacteria, and viruses. A molecular-based knowledge of endocytosis, including macropinocytosis and endosomal escape involving bacteria and viruses, could provide mechanistic insights into exogeneous mitochondrial transfer. We focus on exogeneous mitochondrial transfer in this review to facilitate the clinical development of the use of isolated mitochondria to treat various pathological conditions. Several kinds of novel procedures to enhance exogeneous mitochondrial transfer have been developed and are summarized in this review.
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Subramanian G, Popli S, Chakravarty S, Taylor RT, Chakravarti R, Chattopadhyay S. The interferon-inducible protein TDRD7 inhibits AMP-activated protein kinase and thereby restricts autophagy-independent virus replication. J Biol Chem 2020; 295:6811-6822. [PMID: 32273341 DOI: 10.1074/jbc.ra120.013533] [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] [Received: 03/20/2020] [Revised: 04/03/2020] [Indexed: 12/25/2022] Open
Abstract
The interferon system is the first line of defense against virus infection. Recently, using a high-throughput genetic screen of a human interferon-stimulated gene short-hairpin RNA library, we identified a viral restriction factor, TDRD7 (Tudor domain-containing 7). TDRD7 inhibits the paramyxo-/pneumoviruses (e.g. Sendai virus and respiratory syncytial virus) by interfering with the virus-induced cellular autophagy pathway, which these viruses use for their replication. Here, we report that TDRD7 is a viral restriction factor against herpes simplex virus (HSV-1). Using knockdown, knockout, and ectopic expression systems, we demonstrate the anti-HSV-1 activity of TDRD7 in multiple human and mouse cell types. TDRD7 inhibited the virus-activated AMP-activated protein kinase (AMPK), which was essential for HSV-1 replication. Genetic ablation or chemical inhibition of AMPK activity suppressed HSV-1 replication in multiple human and mouse cells. Mechanistically, HSV-1 replication after viral entry depended on AMPK but not on its function in autophagy. The antiviral activity of TDRD7 depended on its ability to inhibit virus-activated AMPK. In summary, our results indicate that the newly identified viral restriction factor TDRD7 inhibits AMPK and thereby blocks HSV-1 replication independently of the autophagy pathway. These findings suggest that AMPK inhibition represents a potential strategy to manage HSV-1 infections.
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Affiliation(s)
- Gayatri Subramanian
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio 43614
| | - Sonam Popli
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio 43614
| | - Sukanya Chakravarty
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio 43614
| | - R Travis Taylor
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio 43614
| | - Ritu Chakravarti
- Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio 43614
| | - Saurabh Chattopadhyay
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio 43614
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Duplantier AJ, Shurtleff AC, Miller C, Chiang CY, Panchal RG, Sunay M. Combating biothreat pathogens: ongoing efforts for countermeasure development and unique challenges. DRUG DISCOVERY TARGETING DRUG-RESISTANT BACTERIA 2020. [PMCID: PMC7258707 DOI: 10.1016/b978-0-12-818480-6.00007-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Research to discover and develop antibacterial and antiviral drugs with potent activity against pathogens of biothreat concern presents unique methodological and process-driven challenges. Herein, we review laboratory approaches for finding new antibodies, antibiotics, and antiviral molecules for pathogens of biothreat concern. Using high-throughput screening techniques, molecules that directly inhibit a pathogen’s entry, replication, or growth can be identified. Alternatively, molecules that target host proteins can be interesting targets for development when countering biothreat pathogens, due to the modulation of the host immune response or targeting proteins that interfere with the pathways required by the pathogen for replication. Monoclonal and cocktail antibody therapies approved by the Food and Drug Administration for countering anthrax and under development for treatment of Ebola virus infection are discussed. A comprehensive tabular review of current in vitro, in vivo, pharmacokinetic and efficacy datasets has been presented for biothreat pathogens of greatest concern. Finally, clinical trials and animal rule or traditional drug approval pathways are also reviewed. Opinions; interpretations; conclusions; and recommendations are those of the authors and are not necessarily endorsed by the US Army.
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19
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Maurya R, Kumar R, Saran S. AMPKα promotes basal autophagy induction in Dictyostelium discoideum. J Cell Physiol 2019; 235:4941-4953. [PMID: 31680241 DOI: 10.1002/jcp.29373] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 10/07/2019] [Indexed: 01/24/2023]
Abstract
Autophagy is a degradation process, wherein long-lived proteins, damaged organelles, and protein aggregates are degraded to maintain cellular homeostasis. Upon starvation, 5'-AMP-activated protein kinase (AMPK) initiates autophagy. We show that ampkα- cells exhibit 50% reduction in pinocytosis and display defective phagocytosis. Re-expression of AMPKα in ampkα- cells co-localizes with red fluorescence protein-tagged bacteria. The ampkα- cells show reduced cell survival and autophagic flux under basal and starvation conditions. Co-immunoprecipitation studies show conservation of the AMPK-ATG1 axis in basal autophagy. Computational analyses suggest that the N-terminal region of DdATG1 is amenable for interaction with AMPK. Furthermore, β-actin was found to be a novel interacting partner of AMPK, attributed to the alteration in macropinocytosis and phagocytosis in the absence of AMPK. Additionally, ampkα- cells exhibit enhanced poly-ubiquitinated protein levels and allied large ubiquitin-positive protein aggregates. Our findings suggest that AMPK provides links among pinocytosis, phagocytosis, autophagy, and is a requisite for basal autophagy in Dictyostelium.
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Affiliation(s)
- Ranjana Maurya
- Molecular Cell and Developmental Biology Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Rakesh Kumar
- Molecular Cell and Developmental Biology Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Shweta Saran
- Molecular Cell and Developmental Biology Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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20
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Chua SCJH, Tan HQ, Engelberg D, Lim LHK. Alternative Experimental Models for Studying Influenza Proteins, Host-Virus Interactions and Anti-Influenza Drugs. Pharmaceuticals (Basel) 2019; 12:E147. [PMID: 31575020 PMCID: PMC6958409 DOI: 10.3390/ph12040147] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 09/11/2019] [Accepted: 09/12/2019] [Indexed: 12/14/2022] Open
Abstract
Ninety years after the discovery of the virus causing the influenza disease, this malady remains one of the biggest public health threats to mankind. Currently available drugs and vaccines only partially reduce deaths and hospitalizations. Some of the reasons for this disturbing situation stem from the sophistication of the viral machinery, but another reason is the lack of a complete understanding of the molecular and physiological basis of viral infections and host-pathogen interactions. Even the functions of the influenza proteins, their mechanisms of action and interaction with host proteins have not been fully revealed. These questions have traditionally been studied in mammalian animal models, mainly ferrets and mice (as well as pigs and non-human primates) and in cell lines. Although obviously relevant as models to humans, these experimental systems are very complex and are not conveniently accessible to various genetic, molecular and biochemical approaches. The fact that influenza remains an unsolved problem, in combination with the limitations of the conventional experimental models, motivated increasing attempts to use the power of other models, such as low eukaryotes, including invertebrate, and primary cell cultures. In this review, we summarized the efforts to study influenza in yeast, Drosophila, zebrafish and primary human tissue cultures and the major contributions these studies have made toward a better understanding of the disease. We feel that these models are still under-utilized and we highlight the unique potential each model has for better comprehending virus-host interactions and viral protein function.
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Affiliation(s)
- Sonja C J H Chua
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore.
- NUS Immunology Program, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore.
- CREATE-NUS-HUJ Molecular Mechanisms of Inflammatory Diseases Programme, National University of Singapore, Singapore 138602, Singapore.
| | - Hui Qing Tan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore.
- NUS Immunology Program, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore.
| | - David Engelberg
- CREATE-NUS-HUJ Molecular Mechanisms of Inflammatory Diseases Programme, National University of Singapore, Singapore 138602, Singapore.
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore.
- Department of Biological Chemistry, The Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
| | - Lina H K Lim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore.
- NUS Immunology Program, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore.
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21
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Abstract
Coronaviruses are pathogens with a serious impact on human and animal health. They mostly cause enteric or respiratory disease, which can be severe and life threatening, e.g., in the case of the zoonotic coronaviruses causing severe acute respiratory syndrome (SARS) and Middle East Respiratory Syndrome (MERS) in humans. Despite the economic and societal impact of such coronavirus infections, and the likelihood of future outbreaks of additional pathogenic coronaviruses, our options to prevent or treat coronavirus infections remain very limited. This highlights the importance of advancing our knowledge on the replication of these viruses and their interactions with the host. Compared to other +RNA viruses, coronaviruses have an exceptionally large genome and employ a complex genome expression strategy. Next to a role in basic virus replication or virus assembly, many of the coronavirus proteins expressed in the infected cell contribute to the coronavirus-host interplay. For example, by interacting with the host cell to create an optimal environment for coronavirus replication, by altering host gene expression or by counteracting the host’s antiviral defenses. These coronavirus–host interactions are key to viral pathogenesis and will ultimately determine the outcome of infection. Due to the complexity of the coronavirus proteome and replication cycle, our knowledge of host factors involved in coronavirus replication is still in an early stage compared to what is known for some other +RNA viruses. This review summarizes our current understanding of coronavirus–host interactions at the level of the infected cell, with special attention for the assembly and function of the viral RNA-synthesising machinery and the evasion of cellular innate immune responses.
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22
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Thaker SK, Chapa T, Garcia G, Gong D, Schmid EW, Arumugaswami V, Sun R, Christofk HR. Differential Metabolic Reprogramming by Zika Virus Promotes Cell Death in Human versus Mosquito Cells. Cell Metab 2019; 29:1206-1216.e4. [PMID: 30827860 PMCID: PMC6818653 DOI: 10.1016/j.cmet.2019.01.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 12/04/2018] [Accepted: 01/30/2019] [Indexed: 12/11/2022]
Abstract
Zika virus is a pathogen that poses serious consequences, including congenital microcephaly. Although many viruses reprogram host cell metabolism, whether Zika virus alters cellular metabolism and the functional consequences of Zika-induced metabolic changes remain unknown. Here, we show that Zika virus infection differentially reprograms glucose metabolism in human versus C6/36 mosquito cells by increasing glucose use in the tricarboxylic acid cycle in human cells versus increasing glucose use in the pentose phosphate pathway in mosquito cells. Infection of human cells selectively depletes nucleotide triphosphate levels, leading to elevated AMP/ATP ratios, AMP-activated protein kinase (AMPK) phosphorylation, and caspase-mediated cell death. AMPK is also phosphorylated in Zika virus-infected mouse brain. Inhibiting AMPK in human cells decreases Zika virus-mediated cell death, whereas activating AMPK in mosquito cells promotes Zika virus-mediated cell death. These findings suggest that the differential metabolic reprogramming during Zika virus infection of human versus mosquito cells determines whether cell death occurs.
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Affiliation(s)
- Shivani K Thaker
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Travis Chapa
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Gustavo Garcia
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Danyang Gong
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ernst W Schmid
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Vaithilingaraja Arumugaswami
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA 90098, USA
| | - Ren Sun
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; UCLA Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Bioengineering, Samueli School of Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Heather R Christofk
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA; UCLA Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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23
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Kast DJ, Dominguez R. IRSp53 coordinates AMPK and 14-3-3 signaling to regulate filopodia dynamics and directed cell migration. Mol Biol Cell 2019; 30:1285-1297. [PMID: 30893014 PMCID: PMC6724608 DOI: 10.1091/mbc.e18-09-0600] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Filopodia are actin-filled membrane protrusions that play essential roles in cell motility and cell–cell communication and act as precursors of dendritic spines. IRSp53 is an essential regulator of filopodia formation, which couples Rho-GTPase signaling to actin cytoskeleton and membrane remodeling. IRSp53 has three major domains: an N-terminal inverse-BAR (I-BAR) domain, a Cdc42- and SH3-binding CRIB-PR domain, and an SH3 domain that binds downstream cytoskeletal effectors. Phosphorylation sites in the region between the CRIB-PR and SH3 domains mediate the binding of 14-3-3. Yet the mechanism by which 14-3-3 regulates filopodia formation and dynamics and its role in cell migration are poorly understood. Here, we show that phosphorylation-dependent inhibition of IRSp53 by 14-3-3 counters activation by Cdc42 and cytoskeletal effectors, resulting in down-regulation of filopodia dynamics and cancer cell migration. In serum-starved cells, increased IRSp53 phosphorylation triggers 14-3-3 binding, which inhibits filopodia formation and dynamics, irrespective of whether IRSp53 is activated by Cdc42 or downstream effectors (Eps8, Ena/VASP). Pharmacological activation or inhibition of AMPK, respectively, increases or decreases the phosphorylation of two of three sites in IRSp53 implicated in 14-3-3 binding. Mutating these phosphorylation sites reverses 14-3-3-dependent inhibition of filopodia dynamics and cancer cell chemotaxis.
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Affiliation(s)
- David J Kast
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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Kim SM, Nguyen TT, Ravi A, Kubiniok P, Finicle BT, Jayashankar V, Malacrida L, Hou J, Robertson J, Gao D, Chernoff J, Digman MA, Potma EO, Tromberg BJ, Thibault P, Edinger AL. PTEN Deficiency and AMPK Activation Promote Nutrient Scavenging and Anabolism in Prostate Cancer Cells. Cancer Discov 2018; 8:866-883. [PMID: 29572236 PMCID: PMC6030497 DOI: 10.1158/2159-8290.cd-17-1215] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 02/22/2018] [Accepted: 03/20/2018] [Indexed: 12/20/2022]
Abstract
We report that PTEN-deficient prostate cancer cells use macropinocytosis to survive and proliferate under nutrient stress. PTEN loss increased macropinocytosis only in the context of AMPK activation, revealing a general requirement for AMPK in macropinocytosis and a novel mechanism by which AMPK promotes survival under stress. In prostate cancer cells, albumin uptake did not require macropinocytosis, but necrotic cell debris proved a specific macropinocytic cargo. Isotopic labeling confirmed that macropinocytosed necrotic cell proteins fueled new protein synthesis in prostate cancer cells. Supplementation with necrotic debris, but not albumin, also maintained lipid stores, suggesting that macropinocytosis can supply nutrients other than amino acids. Nontransformed prostatic epithelial cells were not macropinocytic, but patient-derived prostate cancer organoids and xenografts and autochthonous prostate tumors all exhibited constitutive macropinocytosis, and blocking macropinocytosis limited prostate tumor growth. Macropinocytosis of extracellular material by prostate cancer cells is a previously unappreciated tumor-microenvironment interaction that could be targeted therapeutically.Significance: As PTEN-deficient prostate cancer cells proliferate in low-nutrient environments by scavenging necrotic debris and extracellular protein via macropinocytosis, blocking macropinocytosis by inhibiting AMPK, RAC1, or PI3K may have therapeutic value, particularly in necrotic tumors and in combination with therapies that cause nutrient stress. Cancer Discov; 8(7); 866-83. ©2018 AACR.See related commentary by Commisso and Debnath, p. 800This article is highlighted in the In This Issue feature, p. 781.
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Affiliation(s)
- Seong M Kim
- Department of Developmental and Cell Biology, University of California, Irvine, California
| | - Tricia T Nguyen
- Department of Developmental and Cell Biology, University of California, Irvine, California
| | - Archna Ravi
- Department of Developmental and Cell Biology, University of California, Irvine, California
| | - Peter Kubiniok
- Department of Chemistry, Université de Montréal, Quebec, Canada
| | - Brendan T Finicle
- Department of Developmental and Cell Biology, University of California, Irvine, California
| | - Vaishali Jayashankar
- Department of Developmental and Cell Biology, University of California, Irvine, California
| | - Leonel Malacrida
- Laboratory for Fluorescence Dynamics, University of California, Irvine, California
- Departamento de Fisiopatología, Hospital del Clínicas, Facultad de Medicia, Universidad de la República, Montevideo, Uruguay
| | - Jue Hou
- Laser Microbeam and Medical Program, Beckman Laser Institute and Medical Clinic, University of California, Irvine, California
| | - Jane Robertson
- Department of Developmental and Cell Biology, University of California, Irvine, California
| | - Dong Gao
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jonathan Chernoff
- Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Michelle A Digman
- Laboratory for Fluorescence Dynamics, University of California, Irvine, California
| | - Eric O Potma
- Laser Microbeam and Medical Program, Beckman Laser Institute and Medical Clinic, University of California, Irvine, California
| | - Bruce J Tromberg
- Laser Microbeam and Medical Program, Beckman Laser Institute and Medical Clinic, University of California, Irvine, California
| | - Pierre Thibault
- Department of Chemistry, Université de Montréal, Quebec, Canada
| | - Aimee L Edinger
- Department of Developmental and Cell Biology, University of California, Irvine, California.
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25
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West C, Silverman N. p38b and JAK-STAT signaling protect against Invertebrate iridescent virus 6 infection in Drosophila. PLoS Pathog 2018; 14:e1007020. [PMID: 29746571 PMCID: PMC5963806 DOI: 10.1371/journal.ppat.1007020] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 05/22/2018] [Accepted: 04/11/2018] [Indexed: 01/19/2023] Open
Abstract
The fruit fly Drosophila melanogaster is a powerful model system for the study of innate immunity in vector insects as well as mammals. For vector insects, it is particularly important to understand all aspects of their antiviral immune defenses, which could eventually be harnessed to control the transmission of human pathogenic viruses. The immune responses controlling RNA viruses in insects have been extensively studied, but the response to DNA virus infections is poorly characterized. Here, we report that infection of Drosophila with the DNA virus Invertebrate iridescent Virus 6 (IIV-6) triggers JAK-STAT signaling and the robust expression of the Turandots, a gene family encoding small secreted proteins. To drive JAK-STAT signaling, IIV-6 infection more immediately induced expression of the unpaireds, a family of IL-6-related cytokine genes, via a pathway that required one of the three Drosophila p38 homologs, p38b. In fact, both Stat92E and p38b were required for the survival of IIV-6 infected flies. In addition, in vitro induction of the unpaireds required an NADPH-oxidase, and in vivo studies demonstrated Nox was required for induction of TotA. These results argue that ROS production, triggered by IIV-6 infection, leads to p38b activation and unpaired expression, and subsequent JAK-STAT signaling, which ultimately protects the fly from IIV-6 infection. Mosquitoes and other biting insects transmit many harmful pathogens to humans, including parasites and viruses. In order to better protect humans from these diseases, we must gain a more complete understanding of how insects successfully—or unsuccessfully—combat these infections. While we know a great deal regarding how insects combat RNA viruses, we know little about their immune response to DNA virus infections. Studies of DNA virus infections may reveal novel immune mechanisms, which could be uniquely effective against DNA virus infections or could be broadly effective against many viruses. In this study, we utilized an invertebrate DNA virus, IIV-6, infection model with the fruit fly Drosophila melanogaster, and found that virus infection activated several innate immune signaling pathways, which help protect the animal against this virus. Eventually, a more complete understanding of the antiviral responses of insects may be useful to restrict virus infections of disease transmitting insects.
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Affiliation(s)
- Cara West
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Neal Silverman
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
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26
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Subramanian G, Kuzmanovic T, Zhang Y, Peter CB, Veleeparambil M, Chakravarti R, Sen GC, Chattopadhyay S. A new mechanism of interferon's antiviral action: Induction of autophagy, essential for paramyxovirus replication, is inhibited by the interferon stimulated gene, TDRD7. PLoS Pathog 2018; 14:e1006877. [PMID: 29381763 PMCID: PMC5806901 DOI: 10.1371/journal.ppat.1006877] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 02/09/2018] [Accepted: 01/12/2018] [Indexed: 12/14/2022] Open
Abstract
The interferon (IFN) system represents the first line of defense against a wide range of viruses. Virus infection rapidly triggers the transcriptional induction of IFN-β and IFN Stimulated Genes (ISGs), whose protein products act as viral restriction factors by interfering with specific stages of virus life cycle, such as entry, transcription, translation, genome replication, assembly and egress. Here, we report a new mode of action of an ISG, IFN-induced TDRD7 (tudor domain containing 7) inhibited paramyxovirus replication by inhibiting autophagy. TDRD7 was identified as an antiviral gene by a high throughput screen of an ISG shRNA library for blocking IFN’s protective effect against Sendai virus (SeV) replication. The antiviral activity of TDRD7 against SeV, human parainfluenza virus 3 and respiratory syncytial virus was confirmed by its genetic ablation or ectopic expression in several types of mouse and human cells. TDRD7’s antiviral action was mediated by its ability to inhibit autophagy, a cellular catabolic process which was robustly induced by SeV infection and required for its replication. Mechanistic investigation revealed that TDRD7 interfered with the activation of AMP-dependent kinase (AMPK), an enzyme required for initiating autophagy. AMPK activity was required for efficient replication of several paramyxoviruses, as demonstrated by its genetic ablation or inhibition of its activity by TDRD7 or chemical inhibitors. Therefore, our study has identified a new antiviral ISG with a new mode of action. The antiviral functions of interferons (IFNs) are mediated by the IFN-induced proteins, encoded by the IFN Stimulated Genes (ISGs). Because ISGs are virus-specific, we performed a high throughput genetic screen to identify novel antiviral ISGs against Sendai virus (SeV), a respirovirus of the Paramyxoviridae family. Our screen isolated a small subset of anti-SeV ISGs, among which we focused on a novel ISG, Tudor domain containing 7 (TDRD7). The antiviral activity of TDRD7 was confirmed by genetic ablation of the endogenous, and the ectopic expression of the exogenous, TDRD7 in human and mouse cell types. Investigation of the mechanism of antiviral action revealed that TDRD7 inhibited ‘virus-induced autophagy’, which was required for the replication of SeV. Autophagy, a cellular catabolic process, was robustly induced by SeV infection, and was inhibited by TDRD7. TDRD7 interfered with the ‘induction’ step of autophagy by inhibiting the activation of AMP-dependent Kinase (AMPK). AMPK is a multifunctional metabolic kinase, which was activated by SeV infection, and its activity was required for virus replication. Genetic ablation and inhibition of AMPK activity by physiological (TDRD7) or chemical (Compound C) inhibitors strongly attenuated SeV replication. The anti-AMPK activity of TDRD7 was capable of inhibiting other members of Paramyxoviridae family, human parainfluenza virus type 3 and respiratory syncytial virus. Therefore, our study uncovered a new antiviral mechanism of IFN by inhibiting the activation of autophagy-inducing kinase AMPK.
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Affiliation(s)
- Gayatri Subramanian
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine, Toledo, OH, United States of America
| | - Teodora Kuzmanovic
- Department of Immunology, Lerner Research Institute, Cleveland, OH, United States of America
| | - Ying Zhang
- Department of Immunology, Lerner Research Institute, Cleveland, OH, United States of America
| | - Cara Beate Peter
- Department of Surgery, University of Toledo College of Medicine, Toledo, OH, United States of America
| | - Manoj Veleeparambil
- Department of Immunology, Lerner Research Institute, Cleveland, OH, United States of America
| | - Ritu Chakravarti
- Department of Surgery, University of Toledo College of Medicine, Toledo, OH, United States of America
| | - Ganes C. Sen
- Department of Immunology, Lerner Research Institute, Cleveland, OH, United States of America
| | - Saurabh Chattopadhyay
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine, Toledo, OH, United States of America
- Department of Immunology, Lerner Research Institute, Cleveland, OH, United States of America
- * E-mail:
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Sobhy H. A comparative review of viral entry and attachment during large and giant dsDNA virus infections. Arch Virol 2017; 162:3567-3585. [PMID: 28866775 PMCID: PMC5671522 DOI: 10.1007/s00705-017-3497-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Accepted: 07/13/2017] [Indexed: 12/19/2022]
Abstract
Viruses enter host cells via several mechanisms, including endocytosis, macropinocytosis, and phagocytosis. They can also fuse at the plasma membrane and can spread within the host via cell-to-cell fusion or syncytia. The mechanism used by a given viral strain depends on its external topology and proteome and the type of cell being entered. This comparative review discusses the cellular attachment receptors and entry pathways of dsDNA viruses belonging to the families Adenoviridae, Baculoviridae, Herpesviridae and nucleocytoplasmic large DNA viruses (NCLDVs) belonging to the families Ascoviridae, Asfarviridae, Iridoviridae, Phycodnaviridae, and Poxviridae, and giant viruses belonging to the families Mimiviridae and Marseilleviridae as well as the proposed families Pandoraviridae and Pithoviridae. Although these viruses have several common features (e.g., topology, replication and protein sequence similarities) they utilize different entry pathways to infect wide-range of hosts, including humans, other mammals, invertebrates, fish, protozoa and algae. Similarities and differences between the entry methods used by these virus families are highlighted, with particular emphasis on viral topology and proteins that mediate viral attachment and entry. Cell types that are frequently used to study viral entry are also reviewed, along with other factors that affect virus-host cell interactions.
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Affiliation(s)
- Haitham Sobhy
- Department of Molecular Biology, Umeå University, 901 87, Umeå, Sweden.
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28
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Moreira D, Silvestre R, Cordeiro-da-Silva A, Estaquier J, Foretz M, Viollet B. AMP-activated Protein Kinase As a Target For Pathogens: Friends Or Foes? Curr Drug Targets 2017; 17:942-53. [PMID: 25882224 DOI: 10.2174/1389450116666150416120559] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 03/24/2015] [Accepted: 04/10/2015] [Indexed: 12/21/2022]
Abstract
Intracellular pathogens are known to manipulate host cell regulatory pathways to establish an optimal environment for their growth and survival. Pathogens employ active mechanisms to hijack host cell metabolism and acquire existing nutrient and energy store. The role of the cellular energy sensor AMP-activated protein kinase (AMPK) in the regulation of cellular energy homeostasis is well documented. Here, we highlight recent advances showing the importance of AMPK signaling in pathogen-host interactions. Pathogens interact with AMPK by a variety of mechanisms aimed at reprogramming host cell metabolism to their own benefit. Stimulation of AMPK activity provides an efficient process to rapidly adapt pathogen metabolism to the major nutritional changes often encountered during the different phases of infection. However, inhibition of AMPK is also used by pathogens to manipulate innate host response, indicating that AMPK appears relevant to restriction of pathogen infection. We also document the effects of pharmacological AMPK modulators on pathogen proliferation and survival. This review illustrates intricate pathogen-AMPK interactions that may be exploited to the development of novel anti-pathogen therapies.
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Affiliation(s)
| | | | | | | | | | - Benoit Viollet
- Institut Cochin, Inserm U1016, CNRS UMR8104, Université Paris Descartes, 24 rue du faubourg Saint Jacques 75014 Paris, France.
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Dengue Virus Activates the AMP Kinase-mTOR Axis To Stimulate a Proviral Lipophagy. J Virol 2017; 91:JVI.02020-16. [PMID: 28298606 DOI: 10.1128/jvi.02020-16] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 03/02/2017] [Indexed: 01/08/2023] Open
Abstract
Robust dengue virus (DENV) replication requires lipophagy, a selective autophagy that targets lipid droplets. The autophagic mobilization of lipids leads to increased β-oxidation in DENV-infected cells. The mechanism by which DENV induces lipophagy is unknown. Here, we show that infection with DENV activates the metabolic regulator 5' adenosine-monophosphate activated kinase (AMPK), and that the silencing or pharmacological inhibition of AMPK activity decreases DENV replication and the induction of lipophagy. The activity of the mechanistic target of rapamycin complex 1 (mTORC1) decreases in DENV-infected cells and is inversely correlated with lipophagy induction. Constitutive activation of mTORC1 by depletion of tuberous sclerosis complex 2 (TSC2) inhibits lipophagy induction in DENV-infected cells and decreases viral replication. While AMPK normally stimulates TSC2-dependent inactivation of mTORC1 signaling, mTORC1 inactivation is independent of AMPK activation during DENV infection. Thus, DENV stimulates and requires AMPK signaling as well as AMPK-independent suppression of mTORC1 activity for proviral lipophagy.IMPORTANCE Dengue virus alters host cell lipid metabolism to promote its infection. One mechanism for altered metabolism is the induction of a selective autophagy that targets lipid droplets, termed lipophagy. Lipophagy mobilizes lipid stores, resulting in enhanced β-oxidation and viral replication. We show here that DENV infection activates and requires the central metabolic regulator AMPK for its replication and the induction of lipophagy. This is required for the induction of lipophagy, but not basal autophagy, in DENV-infected cells.
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Triad of human cellular proteins, IRF2, FAM111A, and RFC3, restrict replication of orthopoxvirus SPI-1 host-range mutants. Proc Natl Acad Sci U S A 2017; 114:3720-3725. [PMID: 28320935 PMCID: PMC5389286 DOI: 10.1073/pnas.1700678114] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Viruses and their hosts can reach balanced states of evolution ensuring mutual survival, which makes it difficult to appreciate the underlying dynamics. To uncover hidden interactions, virus mutants that have lost defense genes may be used. Deletion of the gene that encodes serine protease inhibitor 1 (SPI-1) of rabbitpox virus and vaccinia virus, two closely related orthopoxviruses, prevents their efficient replication in human cells, whereas certain other mammalian cells remain fully permissive. Our high-throughput genome-wide siRNA screen identified host factors that prevent reproduction and spread of the mutant viruses in human cells. More than 20,000 genes were interrogated with individual siRNAs and those that prominently increased replication of the SPI-1 deletion mutant were subjected to a secondary screen. The top hits based on the combined data-replication factor C3 (RFC3), FAM111A, and interferon regulatory factor 2 (IRF2)-were confirmed by custom assays. The siRNAs to RFC1, RFC2, RFC4, and RFC5 mRNAs also enhanced spread of the mutant virus, strengthening the biological significance of the RFC complex as a host restriction factor for poxviruses. Whereas association with proliferating cell nuclear antigen and participation in processive genome replication are common features of FAM111A and RFC, IRF2 is a transcriptional regulator. Microarray analysis, quantitative RT-PCR, and immunoblotting revealed that IRF2 regulated the basal level expression of FAM111A, suggesting that the enhancing effect of depleting IRF2 on replication of the SPI-1 mutant was indirect. Thus, the viral SPI-1 protein and the host IRF2, FAM111A, and RFC complex likely form an interaction network that influences the ability of poxviruses to replicate in human cells.
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Prantner D, Perkins DJ, Vogel SN. AMP-activated Kinase (AMPK) Promotes Innate Immunity and Antiviral Defense through Modulation of Stimulator of Interferon Genes (STING) Signaling. J Biol Chem 2016; 292:292-304. [PMID: 27879319 DOI: 10.1074/jbc.m116.763268] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 11/15/2016] [Indexed: 11/06/2022] Open
Abstract
The host protein Stimulator of Interferon Genes (STING) has been shown to be essential for recognition of both viral and intracellular bacterial pathogens, but its regulation remains unclear. Previously, we reported that mitochondrial membrane potential regulates STING-dependent IFN-β induction independently of ATP synthesis. Because mitochondrial membrane potential controls calcium homeostasis, and AMP-activated protein kinase (AMPK) is regulated, in part, by intracellular calcium, we postulated that AMPK participates in STING activation; however, its role has yet to be been defined. Addition of an intracellular calcium chelator or an AMPK inhibitor to either mouse macrophages or mouse embryonic fibroblasts (MEFs) suppressed IFN-β and TNF-α induction following stimulation with the STING-dependent ligand 5,6-dimethyl xanthnone-4-acetic acid (DMXAA). These pharmacological findings were corroborated by showing that MEFs lacking AMPK activity also failed to up-regulate IFN-β and TNF-α after treatment with DMXAA or the natural STING ligand cyclic GMP-AMP (cGAMP). As a result, AMPK-deficient MEFs exhibit impaired control of vesicular stomatitis virus (VSV), a virus sensed by STING that can cause an influenza-like illness in humans. This impairment could be overcome by pretreatment of AMPK-deficient MEFs with type I IFN, illustrating that de novo production of IFN-β in response to VSV plays a key role in antiviral defense during infection. Loss of AMPK also led to dephosphorylation at Ser-555 of the known STING regulator, UNC-51-like kinase 1 (ULK1). However, ULK1-deficient cells responded normally to DMXAA, indicating that AMPK promotes STING-dependent signaling independent of ULK1 in mouse cells.
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Affiliation(s)
- Daniel Prantner
- From the Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland 21201
| | - Darren J Perkins
- From the Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland 21201
| | - Stefanie N Vogel
- From the Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland 21201
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Suppression of Kaposi's Sarcoma-Associated Herpesvirus Infection and Replication by 5'-AMP-Activated Protein Kinase. J Virol 2016; 90:6515-6525. [PMID: 27147746 DOI: 10.1128/jvi.00624-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Accepted: 04/28/2016] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED The host intracellular antiviral restriction factors inhibit viral infection and replication. The 5'-AMP-activated protein kinase (AMPK) is a cellular energy sensor regulating metabolic homeostasis. Activated AMPK inhibits the replication of numerous RNA viruses but enhances the entry of vaccinia virus. However, the role of AMPK in herpesvirus infection is unclear. In this study, we showed that the constitutive AMPK activity restricted Kaposi's sarcoma-associated herpesvirus (KSHV) lytic replication in primary human umbilical vein endothelial cells while KSHV infection did not markedly affect the endogenous AMPK activity. Knockdown of the AMPKα1 considerably enhanced the expression of viral lytic genes and the production of infectious virions, while overexpression of a constitutively active AMPK had the opposite effects. Accordingly, an AMPK inhibitor, compound C, augmented viral lytic gene expressions and virion productions but an AMPK agonist, 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), suppressed both. Furthermore, a common diabetes drug, metformin, which carries an AMPK-agonistic activity, drastically inhibited the expression of viral lytic genes and the production of infectious virions, suggesting the use of metformin as a therapeutic agent for KSHV infection and replication. Together, these results identify the host AMPK as a KSHV restriction factor that can serve as a potential therapeutic target. IMPORTANCE Host cells encode specific proteins to restrict viral infection and replication. Kaposi's sarcoma-associated herpesvirus (KSHV) is a human tumor virus associated with several cancers. In this study, we have identified 5'-AMP-activated protein kinase (AMPK), a cellular energy sensor, as a restriction factor of KSHV lytic replication during primary infection. Activation of AMPK suppresses, while inhibition of AMPK enhances, KSHV lytic replication by regulating the expression of viral genes. AICAR and metformin, both of which are AMPK agonists currently used in clinics for the treatment of conditions associated with metabolic disorders, inhibit KSHV lytic replication. Thus, our work has identified AMPK as a potential therapeutic target and AICAR and metformin as potential therapeutic agents for KSHV-associated cancers.
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Functional Genomic Strategies for Elucidating Human-Virus Interactions: Will CRISPR Knockout RNAi and Haploid Cells? Adv Virus Res 2016; 94:1-51. [PMID: 26997589 PMCID: PMC7112329 DOI: 10.1016/bs.aivir.2015.11.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Over the last several years a wealth of transformative human–virus interaction discoveries have been produced using loss-of-function functional genomics. These insights have greatly expanded our understanding of how human pathogenic viruses exploit our cells to replicate. Two technologies have been at the forefront of this genetic revolution, RNA interference (RNAi) and random retroviral insertional mutagenesis using haploid cell lines (haploid cell screening), with the former technology largely predominating. Now the cutting edge gene editing of the CRISPR/Cas9 system has also been harnessed for large-scale functional genomics and is poised to possibly displace these earlier methods. Here we compare and contrast these three screening approaches for elucidating host–virus interactions, outline their key strengths and weaknesses including a comparison of an arrayed multiple orthologous RNAi reagent screen to a pooled CRISPR/Cas9 human rhinovirus 14–human cell interaction screen, and recount some notable insights made possible by each. We conclude with a brief perspective on what might lie ahead for the fast evolving field of human–virus functional genomics.
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Mesquita I, Moreira D, Sampaio-Marques B, Laforge M, Cordeiro-da-Silva A, Ludovico P, Estaquier J, Silvestre R. AMPK in Pathogens. EXPERIENTIA SUPPLEMENTUM (2012) 2016; 107:287-323. [PMID: 27812985 DOI: 10.1007/978-3-319-43589-3_12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
During host-pathogen interactions, a complex web of events is crucial for the outcome of infection. Pathogen recognition triggers powerful cellular signaling events that is translated into the induction and maintenance of innate and adaptive host immunity against infection. In opposition, pathogens employ active mechanisms to manipulate host cell regulatory pathways toward their proliferation and survival. Among these, subversion of host cell energy metabolism by pathogens is currently recognized to play an important role in microbial growth and persistence. Extensive studies have documented the role of AMP-activated protein kinase (AMPK) signaling, a central cellular hub involved in the regulation of energy homeostasis, in host-pathogen interactions. Here, we highlight the most recent advances detailing how pathogens hijack cellular metabolism by suppressing or increasing the activity of the host energy sensor AMPK. We also address the role of lower eukaryote AMPK orthologues in the adaptive process to the host microenvironment and their contribution for pathogen survival, differentiation, and growth. Finally, we review the effects of pharmacological or genetic AMPK modulation on pathogen growth and persistence.
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Affiliation(s)
- Inês Mesquita
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.,ICVS/3Bs-PT Government Associate Laboratory, Guimarães, Braga, Portugal
| | - Diana Moreira
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Belém Sampaio-Marques
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.,ICVS/3Bs-PT Government Associate Laboratory, Guimarães, Braga, Portugal
| | | | - Anabela Cordeiro-da-Silva
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Paula Ludovico
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.,ICVS/3Bs-PT Government Associate Laboratory, Guimarães, Braga, Portugal
| | - Jérôme Estaquier
- CNRS FR 3636, Université Paris Descartes, Paris, France.,Centre de Recherche du CHU de Québec, Université Laval, Québec, QC, Canada
| | - Ricardo Silvestre
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal. .,ICVS/3Bs-PT Government Associate Laboratory, Guimarães, Braga, Portugal.
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Abstract
In the fruit fly, Drosophila melanogaster, mono-allelic expression of AMPK-α, -β, and -γ yields a single heterotrimeric energy sensor that regulates cellular and whole-body energetic homeostasis. The genetic simplicity of Drosophila, with only a single gene for each subunit, makes the fruit fly an appealing organism for elucidating the effects of AMPK mutations on signaling pathways and phenotypes. In addition, Drosophila presents researchers with an opportunity to use straightforward genetic approaches to elucidate metabolic signaling pathways that contain a level of complexity similar to that observed in mammalian pathways. Just as in mammals, however, the regulatory realm of AMPK function extends beyond metabolic rates and lipid metabolism. Indeed, experiments using Drosophila have shown that AMPK may exert protective effects with regard to life span and neurodegeneration. This chapter addresses a few of the research areas in which Drosophila has been used to elucidate the physiological functions of AMPK. In doing so, this chapter provides a primer for basic Drosophila nomenclature, thereby eliminating a communication barrier that persists for AMPK researchers trained in mammalian genetics.
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Affiliation(s)
- Sarah E Sinnett
- Gene Therapy Center, University of North Carolina (UNC) at Chapel Hill, Chapel Hill, NC, USA.
| | - Jay E Brenman
- Department of Cell Biology and Physiology, Neuroscience Center, UNC Chapel Hill School of Medicine, Chapel Hill, NC, USA
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Abstract
Deciphering the many interactions that occur between a virus and host cell over the course of infection is paramount to understanding mechanisms of pathogenesis and to the future development of antiviral therapies. Over the past decade, researchers have started to understand these complicated relationships through the development of methodologies, including advances in RNA interference, proteomics, and the development of genetic tools such as haploid cell lines, allowing high-throughput screening to identify critical contact points between virus and host. These advances have produced a wealth of data regarding host factors hijacked by viruses to promote infection, as well as antiviral factors responsible for subverting viral infection. This review highlights findings from virus-host screens and discusses our thoughts on the direction of screening strategies moving forward.
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Affiliation(s)
- Holly Ramage
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104; ,
| | - Sara Cherry
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104; ,
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Virus-induced translational arrest through 4EBP1/2-dependent decay of 5'-TOP mRNAs restricts viral infection. Proc Natl Acad Sci U S A 2015; 112:E2920-9. [PMID: 26038567 DOI: 10.1073/pnas.1418805112] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The mosquito-transmitted bunyavirus, Rift Valley fever virus (RVFV), is a highly successful pathogen for which there are no vaccines or therapeutics. Translational arrest is a common antiviral strategy used by hosts. In response, RVFV inhibits two well-known antiviral pathways that attenuate translation during infection, PKR and type I IFN signaling. Despite this, translational arrest occurs during RVFV infection by unknown mechanisms. Here, we find that RVFV infection triggers the decay of core translation machinery mRNAs that possess a 5'-terminal oligopyrimidine (5'-TOP) motif in their 5'-UTR, including mRNAs encoding ribosomal proteins, which leads to a decrease in overall ribosomal protein levels. We find that the RNA decapping enzyme NUDT16 selectively degrades 5'-TOP mRNAs during RVFV infection and this decay is triggered in response to mTOR attenuation via the translational repressor 4EBP1/2 axis. Translational arrest of 5'-TOPs via 4EBP1/2 restricts RVFV replication, and this increased RNA decay results in the loss of visible RNA granules, including P bodies and stress granules. Because RVFV cap-snatches in RNA granules, the increased level of 5'-TOP mRNAs in this compartment leads to snatching of these targets, which are translationally suppressed during infection. Therefore, translation of RVFV mRNAs is compromised by multiple mechanisms during infection. Together, these data present a previously unknown mechanism for translational shutdown in response to viral infection and identify mTOR attenuation as a potential therapeutic avenue against bunyaviral infection.
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RAB1A promotes Vaccinia virus replication by facilitating the production of intracellular enveloped virions. Virology 2014; 475:66-73. [PMID: 25462347 PMCID: PMC4292983 DOI: 10.1016/j.virol.2014.11.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 09/16/2014] [Accepted: 11/05/2014] [Indexed: 12/31/2022]
Abstract
Vaccinia virus (VACV) is a large double-stranded DNA virus with a complex cytoplasmic replication cycle that exploits numerous cellular proteins. This work characterises the role of a proviral cellular protein, the small GTPase RAB1A, in VACV replication. Using siRNA, we identified RAB1A as required for the production of extracellular enveloped virions (EEVs), but not intracellular mature virions (IMVs). Immunofluorescence and electron microscopy further refined the role of RAB1A as facilitating the wrapping of IMVs to become intracellular enveloped virions (IEVs). This is consistent with the known function of RAB1A in maintenance of ER to Golgi transport. VACV can therefore be added to the growing list of viruses which require RAB1A for optimal replication, highlighting this protein as a broadly proviral host factor.
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Abstract
The actin cytoskeleton and its network of associated proteins constitute a physical barrier that viruses must circumvent to gain entry into cells for productive infection. The mechanisms by which the physical signals of infection are sensed by the host to activate an innate immune response are not well understood. The antiviral endoribonuclease RNase L is ubiquitously expressed in a latent form and activated upon binding 2-5A, a unique oligoadenylate produced during viral infections. We provide evidence that RNase L in its inactive form interacts with the actin-binding protein Filamin A to modulate the actin cytoskeleton and inhibit virus entry. Cells lacking either RNase L or Filamin A displayed increased virus entry which was exacerbated in cells lacking both proteins. RNase L deletion mutants that reduced Filamin A interaction displayed a compromised ability to restrict virus entry, supporting the idea of an important role for the RNase L-Filamin A complex in barrier function. Remarkably, both the wild type and a catalytically inactive RNase L mutant were competent to reduce virus entry when transfected into RNase L-deficient cells, indicating that this novel function of RNase L is independent of its enzymatic activity. Virus infection and RNase L activation disrupt its association with Filamin A and release RNase L to mediate its canonical nuclease-dependent antiviral activities. The dual functions of RNase L as a constitutive component of the actin cytoskeleton and as an induced mediator of antiviral signaling and effector functions provide insights into its mechanisms of antiviral activity and opportunities for the development of novel antiviral agents. Cells constantly face and sample pathogens on their outer surface. The actin cytoskeleton and interacting proteins associate with the cell membrane and constitute a barrier to infection. Disruption of the actin cytoskeleton allows viruses to enter the cell and induces innate immune responses to clear infections. The molecular mechanisms that link virus-induced physical perturbations to host defense pathways remain unclear. Our studies identified a novel interaction between the antiviral endoribonuclease RNase L and the actin-binding protein Filamin A that enhances host defense by preventing viral entry into naive cells. This role for RNase L is independent of its enzymatic function. Virus infection alters actin dynamics, disrupts the RNase L-Filamin A complex, and releases RNase L to mediate antiviral signaling and effector functions via its established nucleolytic activities. These dual roles for RNase L provide an efficient strategy to protect cells from infection and rapidly respond upon pathogen exposure.
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Moller-Tank S, Maury W. Phosphatidylserine receptors: enhancers of enveloped virus entry and infection. Virology 2014; 468-470:565-580. [PMID: 25277499 PMCID: PMC4252826 DOI: 10.1016/j.virol.2014.09.009] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 07/15/2014] [Accepted: 09/08/2014] [Indexed: 12/23/2022]
Abstract
A variety of both RNA and DNA viruses envelop their capsids in a lipid bilayer. One of the more recently appreciated benefits this envelope is incorporation of phosphatidylserine (PtdSer). Surface exposure of PtdSer disguises viruses as apoptotic bodies; tricking cells into engulfing virions. This mechanism is termed apoptotic mimicry. Several PtdSer receptors have been identified to enhance virus entry and we have termed this group of proteins PtdSer-mediated virus entry enhancing receptors or PVEERs. These receptors enhance entry of a range of enveloped viruses. Internalization of virions by PVEERs provides a broad mechanism of entry with little investment by the virus itself. PVEERs may allow some viruses to attach to cells, thereby making viral glycoprotein/cellular receptor interactions more probable. Alternatively, other viruses may rely entirely on PVEERs for internalization into endosomes. This review provides an overview of PtdSer receptors that serve as PVEERs and the biology behind virion/PVEER interaction. Phosphatidylserine (PtdSer) receptors can mediate entry of enveloped viruses. PtdSer is present on the outer leaflet of the virion envelope. PtdSer receptors are expressed on a variety of primary cells and cell lines. Characteristics of PtdSer receptors that mediate virus entry are defined.
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Affiliation(s)
- Sven Moller-Tank
- Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA
| | - Wendy Maury
- Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA.
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41
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Le Dréan G, Segain JP. Connecting metabolism to intestinal barrier function: The role of leptin. Tissue Barriers 2014; 2:e970940. [PMID: 25610758 DOI: 10.4161/21688362.2014.970940] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 09/25/2014] [Indexed: 12/16/2022] Open
Abstract
Structure and function of the intestinal epithelial barrier (IEB) are dependent upon the integrity of junctional protein structures sealing the apical surface between epithelial cells. Tight junctions (TJ) and the surrounding apical F-actin cytoskeleton are involved in the regulation of paracellular permeability. The regulation of actin cytoskeleton organization by RhoA/Rho-kinase (ROCK) pathway plays an important role in TJ assembly and function. There is mounting evidence that the adipocyte-derived hormone leptin exerts pleiotropic effects on the intestinal epithelium including nutrient absorption, epithelial growth, inflammation and injury. Leptin activates multiple cell signaling pathways in intestinal epithelial cells (IEC) that can explain these pleiotropic effects. However, these pathways are also involved in the primary role of leptin that is the regulation of energy and glucose metabolism homeostasis. In this commentary, we examine how the interplay between leptin signaling pathways that regulate cell metabolism could impact upon IEB function.
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Key Words
- AMPK
- AMPK, AMP-activated protein kinase
- IEB, intestinal epithelial barrier
- IEC, intestinal epithelial cells
- JAK, Janus kinase
- JAK/STAT
- LepR-b, leptin receptor
- MEF, mouse embryonic fibroblast
- MLC, myosin light chain
- ROCK, Rho-kinase
- RhoA/ROCK
- STAT, signal transducer and activator of transcription
- TJ, tight junctions
- VAT, visceral adipose tissue
- barrier repair
- intestinal epithelial barrier
- leptin
- metabolism
- tight-junction
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Affiliation(s)
- Gwenola Le Dréan
- Université de Nantes; Institut des Maladies de l'Appareil Digestif (IMAD); Centre de Recherche en Nutrition Humaine du Grand Ouest (CRNH) ; Nantes, France ; CHU Hôtel-Dieu, Place Alexis Ricordeau ; Nantes, France
| | - Jean-Pierre Segain
- Université de Nantes; Institut des Maladies de l'Appareil Digestif (IMAD); Centre de Recherche en Nutrition Humaine du Grand Ouest (CRNH) ; Nantes, France ; CHU Hôtel-Dieu, Place Alexis Ricordeau ; Nantes, France
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Gammon DB, Duraffour S, Rozelle DK, Hehnly H, Sharma R, Sparks ME, West CC, Chen Y, Moresco JJ, Andrei G, Connor JH, Conte D, Gundersen-Rindal DE, Marshall WL, Yates JR, Silverman N, Mello CC. A single vertebrate DNA virus protein disarms invertebrate immunity to RNA virus infection. eLife 2014; 3:e02910. [PMID: 24966209 PMCID: PMC4112549 DOI: 10.7554/elife.02910] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 06/25/2014] [Indexed: 12/12/2022] Open
Abstract
Virus-host interactions drive a remarkable diversity of immune responses and countermeasures. We found that two RNA viruses with broad host ranges, vesicular stomatitis virus (VSV) and Sindbis virus (SINV), are completely restricted in their replication after entry into Lepidopteran cells. This restriction is overcome when cells are co-infected with vaccinia virus (VACV), a vertebrate DNA virus. Using RNAi screening, we show that Lepidopteran RNAi, Nuclear Factor-κB, and ubiquitin-proteasome pathways restrict RNA virus infection. Surprisingly, a highly conserved, uncharacterized VACV protein, A51R, can partially overcome this virus restriction. We show that A51R is also critical for VACV replication in vertebrate cells and for pathogenesis in mice. Interestingly, A51R colocalizes with, and stabilizes, host microtubules and also associates with ubiquitin. We show that A51R promotes viral protein stability, possibly by preventing ubiquitin-dependent targeting of viral proteins for destruction. Importantly, our studies reveal exciting new opportunities to study virus-host interactions in experimentally-tractable Lepidopteran systems.
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Affiliation(s)
- Don B Gammon
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
| | | | - Daniel K Rozelle
- Department of Microbiology, Boston University, Boston, United States
| | - Heidi Hehnly
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, United States
| | - Rita Sharma
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
- Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, United States
| | - Michael E Sparks
- Agricultural Research Service, United States Department of Agriculture, Beltsville, United States
| | - Cara C West
- Department of Medicine, University of Massachusetts Medical School, Worcester, United States
| | - Ying Chen
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
| | - James J Moresco
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, United States
| | - Graciela Andrei
- Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - John H Connor
- Department of Microbiology, Boston University, Boston, United States
| | - Darryl Conte
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
| | - Dawn E Gundersen-Rindal
- Agricultural Research Service, United States Department of Agriculture, Beltsville, United States
| | - William L Marshall
- Department of Medicine, University of Massachusetts Medical School, Worcester, United States
| | - John R Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, United States
| | - Neal Silverman
- Department of Medicine, University of Massachusetts Medical School, Worcester, United States
| | - Craig C Mello
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
- Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, United States
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A loss of function analysis of host factors influencing Vaccinia virus replication by RNA interference. PLoS One 2014; 9:e98431. [PMID: 24901222 PMCID: PMC4047015 DOI: 10.1371/journal.pone.0098431] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 04/23/2014] [Indexed: 02/08/2023] Open
Abstract
Vaccinia virus (VACV) is a large, cytoplasmic, double-stranded DNA virus that requires complex interactions with host proteins in order to replicate. To explore these interactions a functional high throughput small interfering RNA (siRNA) screen targeting 6719 druggable cellular genes was undertaken to identify host factors (HF) influencing the replication and spread of an eGFP-tagged VACV. The experimental design incorporated a low multiplicity of infection, thereby enhancing detection of cellular proteins involved in cell-to-cell spread of VACV. The screen revealed 153 pro- and 149 anti-viral HFs that strongly influenced VACV replication. These HFs were investigated further by comparisons with transcriptional profiling data sets and HFs identified in RNAi screens of other viruses. In addition, functional and pathway analysis of the entire screen was carried out to highlight cellular mechanisms involved in VACV replication. This revealed, as anticipated, that many pro-viral HFs are involved in translation of mRNA and, unexpectedly, suggested that a range of proteins involved in cellular transcriptional processes and several DNA repair pathways possess anti-viral activity. Multiple components of the AMPK complex were found to act as pro-viral HFs, while several septins, a group of highly conserved GTP binding proteins with a role in sequestering intracellular bacteria, were identified as strong anti-viral VACV HFs. This screen has identified novel and previously unexplored roles for cellular factors in poxvirus replication. This advancement in our understanding of the VACV life cycle provides a reliable knowledge base for the improvement of poxvirus-based vaccine vectors and development of anti-viral theraputics.
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Filone CM, Caballero IS, Dower K, Mendillo ML, Cowley GS, Santagata S, Rozelle DK, Yen J, Rubins KH, Hacohen N, Root DE, Hensley LE, Connor J. The master regulator of the cellular stress response (HSF1) is critical for orthopoxvirus infection. PLoS Pathog 2014; 10:e1003904. [PMID: 24516381 PMCID: PMC3916389 DOI: 10.1371/journal.ppat.1003904] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 12/12/2013] [Indexed: 12/17/2022] Open
Abstract
The genus Orthopoxviridae contains a diverse group of human pathogens including monkeypox, smallpox and vaccinia. These viruses are presumed to be less dependent on host functions than other DNA viruses because they have large genomes and replicate in the cytoplasm, but a detailed understanding of the host factors required by orthopoxviruses is lacking. To address this topic, we performed an unbiased, genome-wide pooled RNAi screen targeting over 17,000 human genes to identify the host factors that support orthopoxvirus infection. We used secondary and tertiary assays to validate our screen results. One of the strongest hits was heat shock factor 1 (HSF1), the ancient master regulator of the cytoprotective heat-shock response. In investigating the behavior of HSF1 during vaccinia infection, we found that HSF1 was phosphorylated, translocated to the nucleus, and increased transcription of HSF1 target genes. Activation of HSF1 was supportive for virus replication, as RNAi knockdown and HSF1 small molecule inhibition prevented orthopoxvirus infection. Consistent with its role as a transcriptional activator, inhibition of several HSF1 targets also blocked vaccinia virus replication. These data show that orthopoxviruses co-opt host transcriptional responses for their own benefit, thereby effectively extending their functional genome to include genes residing within the host DNA. The dependence on HSF1 and its chaperone network offers multiple opportunities for antiviral drug development.
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Affiliation(s)
- Claire Marie Filone
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
- United States Army Medical Research Institute of Infectious Diseases, Virology Division, Fort Detrick, Maryland, United States of America
- * E-mail:
| | - Ignacio S. Caballero
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Ken Dower
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Marc L. Mendillo
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Glenn S. Cowley
- The Broad Institute, Cambridge Massachusetts, United States of America
| | - Sandro Santagata
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Daniel K. Rozelle
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Judy Yen
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Kathleen H. Rubins
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Nir Hacohen
- The Broad Institute, Cambridge Massachusetts, United States of America
| | - David E. Root
- The Broad Institute, Cambridge Massachusetts, United States of America
| | - Lisa E. Hensley
- United States Army Medical Research Institute of Infectious Diseases, Virology Division, Fort Detrick, Maryland, United States of America
| | - John Connor
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
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Liu X, Chhipa RR, Nakano I, Dasgupta B. The AMPK inhibitor compound C is a potent AMPK-independent antiglioma agent. Mol Cancer Ther 2014; 13:596-605. [PMID: 24419061 DOI: 10.1158/1535-7163.mct-13-0579] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
AMP-activated protein kinase (AMPK) is an evolutionarily conserved energy sensor important for cell growth, proliferation, survival, and metabolic regulation. Active AMPK inhibits biosynthetic enzymes like mTOR and acetyl CoA carboxylase (required for protein and lipid synthesis, respectively) to ensure that cells maintain essential nutrients and energy during metabolic crisis. Despite our knowledge about this incredibly important kinase, no specific chemical inhibitors are available to examine its function. However, one small molecule known as compound C (also called dorsomorphin) has been widely used in cell-based, biochemical, and in vivo assays as a selective AMPK inhibitor. In nearly all these reports including a recent study in glioma, the biochemical and cellular effects of compound C have been attributed to its inhibitory action toward AMPK. While examining the status of AMPK activation in human gliomas, we observed that glioblastomas express copious amount of active AMPK. Compound C effectively reduced glioma viability in vitro both by inhibiting proliferation and inducing cell death. As expected, compound C inhibited AMPK; however, all the antiproliferative effects of this compound were AMPK independent. Instead, compound C killed glioma cells by multiple mechanisms, including activation of the calpain/cathepsin pathway, inhibition of AKT, mTORC1/C2, cell-cycle block at G2-M, and induction of necroptosis and autophagy. Importantly, normal astrocytes were significantly less susceptible to compound C. In summary, compound C is an extremely potent antiglioma agent but we suggest that caution should be taken in interpreting results when this compound is used as an AMPK inhibitor.
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Affiliation(s)
- Xiaona Liu
- Corresponding Author: Biplab Dasgupta, Department of Oncology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229.
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Xu J, Cherry S. Viruses and antiviral immunity in Drosophila. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 42:67-84. [PMID: 23680639 PMCID: PMC3826445 DOI: 10.1016/j.dci.2013.05.002] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 04/26/2013] [Accepted: 05/02/2013] [Indexed: 05/10/2023]
Abstract
Viral pathogens present many challenges to organisms, driving the evolution of a myriad of antiviral strategies to combat infections. A wide variety of viruses infect invertebrates, including both natural pathogens that are insect-restricted, and viruses that are transmitted to vertebrates. Studies using the powerful tools in the model organism Drosophila have expanded our understanding of antiviral defenses against diverse viruses. In this review, we will cover three major areas. First, we will describe the tools used to study viruses in Drosophila. Second, we will survey the major viruses that have been studied in Drosophila. And lastly, we will discuss the well-characterized mechanisms that are active against these diverse pathogens, focusing on non-RNAi mediated antiviral mechanisms. Antiviral RNAi is discussed in another paper in this issue.
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Affiliation(s)
- Jie Xu
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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47
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Valanne S. Functional genomic analysis of the Drosophila immune response. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 42:93-101. [PMID: 23707784 DOI: 10.1016/j.dci.2013.05.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 05/13/2013] [Accepted: 05/13/2013] [Indexed: 06/02/2023]
Abstract
Drosophila melanogaster has been widely used as a model organism for over a century now, and also as an immunological research model for over 20 years. With the emergence of RNA interference (RNAi) in Drosophila as a robust tool to silence genes of interest, large-scale or genome-wide functional analysis has become a popular way of studying the Drosophila immune response in cell culture. Drosophila immunity is composed of cellular and humoral immunity mechanisms, and especially the systemic, humoral response pathways have been extensively dissected using the functional genomic approach. Although most components of the main immune pathways had already been found using traditional genetic screening techniques, important findings including pathway components, positive and negative regulators and modifiers have been made with RNAi screening. Additionally, RNAi screening has produced new information on host-pathogen interactions related to the pathogenesis of many microbial species.
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Affiliation(s)
- Susanna Valanne
- Institute of Biomedical Technology and BioMediTech, Tampere University, 33520 Tampere, Finland.
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48
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Hopkins KC, McLane LM, Maqbool T, Panda D, Gordesky-Gold B, Cherry S. A genome-wide RNAi screen reveals that mRNA decapping restricts bunyaviral replication by limiting the pools of Dcp2-accessible targets for cap-snatching. Genes Dev 2013; 27:1511-25. [PMID: 23824541 DOI: 10.1101/gad.215384.113] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Bunyaviruses are an emerging group of medically important viruses, many of which are transmitted from insects to mammals. To identify host factors that impact infection, we performed a genome-wide RNAi screen in Drosophila and identified 131 genes that impacted infection of the mosquito-transmitted bunyavirus Rift Valley fever virus (RVFV). Dcp2, the catalytic component of the mRNA decapping machinery, and two decapping activators, DDX6 and LSM7, were antiviral against disparate bunyaviruses in both insect cells and adult flies. Bunyaviruses 5' cap their mRNAs by "cap-snatching" the 5' ends of poorly defined host mRNAs. We found that RVFV cap-snatches the 5' ends of Dcp2 targeted mRNAs, including cell cycle-related genes. Loss of Dcp2 allows increased viral transcription without impacting viral mRNA stability, while ectopic expression of Dcp2 impedes viral transcription. Furthermore, arresting cells in late S/early G2 led to increased Dcp2 mRNA targets and increased RVFV replication. Therefore, RVFV competes for the Dcp2-accessible mRNA pool, which is dynamically regulated and can present a bottleneck for viral replication.
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49
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Abstract
Placental trophoblasts form the interface between the fetal and maternal environments and serve to limit the maternal-fetal spread of viruses. Here we show that cultured primary human placental trophoblasts are highly resistant to infection by a number of viruses and, importantly, confer this resistance to nonplacental recipient cells by exosome-mediated delivery of specific microRNAs (miRNAs). We show that miRNA members of the chromosome 19 miRNA cluster, which are almost exclusively expressed in the human placenta, are packaged within trophoblast-derived exosomes and attenuate viral replication in recipient cells by the induction of autophagy. Together, our findings identify an unprecedented paracrine and/or systemic function of placental trophoblasts that uses exosome-mediated transfer of a unique set of placental-specific effector miRNAs to directly communicate with placental or maternal target cells and regulate their immunity to viral infections.
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50
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A whole-genome RNA interference screen for human cell factors affecting myxoma virus replication. J Virol 2013; 87:4623-41. [PMID: 23408614 DOI: 10.1128/jvi.02617-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Myxoma virus (MYXV) provides an important model for investigating host-pathogen interactions. Recent studies have also highlighted how mutations in transformed human cells can expand the host range of this rabbit virus. Although virus growth depends upon interactions between virus and host proteins, the nature of these interactions is poorly understood. To address this matter, we performed small interfering RNA (siRNA) screens for genes affecting MYXV growth in human MDA-MB-231 cells. By using siRNAs targeting the whole human genome (21,585 genes), a subset of human phosphatases and kinases (986 genes), and also a custom siRNA library targeting selected statistically significant genes ("hits") and nonsignificant genes ("nonhits") of the whole human genome screens (88 genes), we identified 711 siRNA pools that promoted MYXV growth and 333 that were inhibitory. Another 32 siRNA pools (mostly targeting the proteasome) were toxic. The overall overlap in the results was about 25% for the hits and 75% for the nonhits. These pro- and antiviral genes can be clustered into pathways and related groups, including well-established inflammatory and mitogen-activated protein kinase pathways, as well as clusters relating to β-catenin and the Wnt signaling cascade, the cell cycle, and cellular metabolism. The validity of a subset of these hits was independently confirmed. For example, treating cells with siRNAs that might stabilize cells in G(1), or inhibit passage into S phase, stimulated MYXV growth, and these effects were reproduced by trapping cells at the G(1)/S boundary with an inhibitor of cyclin-dependent kinases 4/6. By using 2-deoxy-D-glucose and plasmids carrying the gene for phosphofructokinase, we also confirmed that infection is favored by aerobic glycolytic metabolism. These studies provide insights into how the growth state and structure of cells affect MYXV growth and how these factors might be manipulated to advantage in oncolytic virus therapy.
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