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Pannhorst K, Carlson J, Hölper JE, Grey F, Baillie JK, Höper D, Wöhnke E, Franzke K, Karger A, Fuchs W, Mettenleiter TC. The non-classical major histocompatibility complex II protein SLA-DM is crucial for African swine fever virus replication. Sci Rep 2023; 13:10342. [PMID: 37604847 PMCID: PMC10442341 DOI: 10.1038/s41598-023-36788-9] [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: 12/08/2022] [Accepted: 06/09/2023] [Indexed: 08/23/2023] Open
Abstract
African swine fever virus (ASFV) is a lethal animal pathogen that enters its host cells through endocytosis. So far, host factors specifically required for ASFV replication have been barely identified. In this study a genome-wide CRISPR/Cas9 knockout screen in porcine cells indicated that the genes RFXANK, RFXAP, SLA-DMA, SLA-DMB, and CIITA are important for productive ASFV infection. The proteins encoded by these genes belong to the major histocompatibility complex II (MHC II), or swine leucocyte antigen complex II (SLA II). RFXAP and CIITA are MHC II-specific transcription factors, whereas SLA-DMA/B are subunits of the non-classical MHC II molecule SLA-DM. Targeted knockout of either of these genes led to severe replication defects of different ASFV isolates, reflected by substantially reduced plating efficiency, cell-to-cell spread, progeny virus titers and viral DNA replication. Transgene-based reconstitution of SLA-DMA/B fully restored the replication capacity demonstrating that SLA-DM, which resides in late endosomes, plays a crucial role during early steps of ASFV infection.
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Affiliation(s)
- Katrin Pannhorst
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
| | - Jolene Carlson
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald-Insel Riems, Germany
- Ceva Animal Health, Greifswald-Insel Riems, Germany
| | - Julia E Hölper
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Finn Grey
- The Roslin Institute, University of Edinburgh, Midlothian, UK
| | | | - Dirk Höper
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Elisabeth Wöhnke
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Kati Franzke
- Institute of Infectology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Axel Karger
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Walter Fuchs
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald-Insel Riems, Germany
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Netherton CL, Shimmon GL, Hui JYK, Connell S, Reis AL. African Swine Fever Virus Host-Pathogen Interactions. Subcell Biochem 2023; 106:283-331. [PMID: 38159232 DOI: 10.1007/978-3-031-40086-5_11] [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] [Indexed: 01/03/2024]
Abstract
African swine fever virus is a complex double-stranded DNA virus that exhibits tropism for cells of the mononuclear phagocytic system. Virus replication is a multi-step process that involves the nucleus of the host cell as well the formation of large perinuclear sites where progeny virions are assembled prior to transport to, and budding through, the plasma membrane. Like many viruses, African swine fever virus reorganises the cellular architecture to facilitate its replication and has evolved multiple mechanisms to avoid the potential deleterious effects of host cell stress response pathways. However, how viral proteins and virus-induced structures trigger cellular stress pathways and manipulate the subsequent responses is still relatively poorly understood. African swine fever virus alters nuclear substructures, modulates autophagy, apoptosis and the endoplasmic reticulum stress response pathways. The viral genome encodes for at least 150 genes, of which approximately 70 are incorporated into the virion. Many of the non-structural genes have not been fully characterised and likely play a role in host range and modifying immune responses. As the field moves towards approaches that take a broader view of the effect of expression of individual African swine fever genes, we summarise how the different steps in virus replication interact with the host cell and the current state of knowledge on how it modulates the resulting stress responses.
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Li Z, Chen W, Qiu Z, Li Y, Fan J, Wu K, Li X, Zhao M, Ding H, Fan S, Chen J. African Swine Fever Virus: A Review. Life (Basel) 2022; 12:1255. [PMID: 36013434 PMCID: PMC9409812 DOI: 10.3390/life12081255] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/29/2022] [Accepted: 07/29/2022] [Indexed: 11/16/2022] Open
Abstract
African swine fever (ASF) is a viral disease with a high fatality rate in both domestic pigs and wild boars. ASF has greatly challenged pig-raising countries and also negatively impacted regional and national trade of pork products. To date, ASF has spread throughout Africa, Europe, and Asia. The development of safe and effective ASF vaccines is urgently required for the control of ASF outbreaks. The ASF virus (ASFV), the causative agent of ASF, has a large genome and a complex structure. The functions of nearly half of its viral genes still remain to be explored. Knowledge on the structure and function of ASFV proteins, the mechanism underlying ASFV infection and immunity, and the identification of major immunogenicity genes will contribute to the development of an ASF vaccine. In this context, this paper reviews the available knowledge on the structure, replication, protein function, virulence genes, immune evasion, inactivation, vaccines, control, and diagnosis of ASFV.
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Affiliation(s)
- Zhaoyao Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Wenxian Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Zilong Qiu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Yuwan Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Jindai Fan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Keke Wu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Xiaowen Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Mingqiu Zhao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Hongxing Ding
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Shuangqi Fan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Jinding Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
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Spatiotemporally Orchestrated Interactions between Viral and Cellular Proteins Involved in the Entry of African Swine Fever Virus. Viruses 2021; 13:v13122495. [PMID: 34960765 PMCID: PMC8703583 DOI: 10.3390/v13122495] [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: 11/04/2021] [Revised: 11/27/2021] [Accepted: 12/09/2021] [Indexed: 12/11/2022] Open
Abstract
African swine fever (ASF) is a highly contagious hemorrhagic disease in domestic pigs and wild boars with a mortality of up to 100%. The causative agent, African swine fever virus (ASFV), is a member of the Asfarviridae family of the nucleocytoplasmic large DNA viruses. The genome size of ASFV ranges from 170 to 194 kb, encoding more than 50 structural and 100 nonstructural proteins. ASFV virions are 260–300 nm in diameter and composed of complex multilayered structures, leading to an intricate internalization pathway to enter host cells. Currently, no commercial vaccines or antivirals are available, due to the insufficient knowledge of the viral receptor(s), the molecular events of ASFV entry into host cells, and the functions of virulence-associated genes. During the early stage of ASFV infection, the fundamental aspects of virus-host interactions, including virus internalization, intracellular transport through the endolysosomal system, and membrane fusion with endosome, are precisely regulated and orchestrated via a series of molecular events. In this review, we summarize the currently available knowledge on the pathways of ASFV entry into host cells and the functions of viral proteins involved in virus entry. Furthermore, we conclude with future perspectives and highlight areas that require further investigation. This review is expected to provide unique insights for further understanding ASFV entry and facilitate the development of vaccines and antivirals.
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Karger A, Pérez-Núñez D, Urquiza J, Hinojar P, Alonso C, Freitas FB, Revilla Y, Le Potier MF, Montoya M. An Update on African Swine Fever Virology. Viruses 2019; 11:v11090864. [PMID: 31533244 PMCID: PMC6784044 DOI: 10.3390/v11090864] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/05/2019] [Accepted: 09/11/2019] [Indexed: 02/06/2023] Open
Abstract
Animal diseases constitute a continuing threat to animal health, food safety, national economy, and the environment. Among those, African swine fever (ASF) is one of the most devastating viruses affecting pigs and wild suids due to the lack of vaccine or effective treatment. ASF is endemic in countries in sub-Saharan Africa, but since its introduction to the Caucasus region in 2007, a highly virulent strain of ASF virus (ASFV) has continued to circulate and spread into Eastern Europe and Russia, and most recently into Western Europe, China, and various countries of Southeast Asia. Given the importance of this disease, this review will highlight recent discoveries in basic virology with special focus on proteomic analysis, replication cycle, and some recent data on genes involved in cycle progression and viral–host interactions, such as I215L (E2 ubiquitin-conjugating enzyme), EP402R (CD2v), A104R (histone-like protein), QP509L, and Q706L (RNA helicases) or P1192R (Topoisomerase II). Taking into consideration the large DNA genome of ASFV and its complex interactions with the host, more studies and new approaches are to be taken to understand the basic virus–host interaction for ASFV. Proteomic studies are just paving the way for future research.
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Affiliation(s)
- Axel Karger
- Institute of Molecular Virology and Cell Biology, Friedrich Loeffler Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany;
| | - Daniel Pérez-Núñez
- Virology Department, Centro Biología Molecular Severo Ochoa, CSIC-UAM, 28049 Madrid, Spain; (D.P.-N.); (Y.R.)
| | - Jesús Urquiza
- INIA, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28040 Madrid, Spain; (J.U.); (P.H.); (C.A.)
| | - Patricia Hinojar
- INIA, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28040 Madrid, Spain; (J.U.); (P.H.); (C.A.)
| | - Covadonga Alonso
- INIA, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28040 Madrid, Spain; (J.U.); (P.H.); (C.A.)
| | - Ferdinando B. Freitas
- Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, 1649-004 Lisboa, Portugal;
| | - Yolanda Revilla
- Virology Department, Centro Biología Molecular Severo Ochoa, CSIC-UAM, 28049 Madrid, Spain; (D.P.-N.); (Y.R.)
| | - Marie-Frédérique Le Potier
- ANSES, Laboratoire de Ploufragan/Plouzané/Niort, Unité Virologie Immunologie Porcines, Anses, 22440 Ploufragan, France;
| | - Maria Montoya
- Centro de Investigaciones Biológicas (CIB-CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
- Correspondence:
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Jatuyosporn T, Laohawutthichai P, Supungul P, Sotelo-Mundo RR, Ochoa-Leyva A, Tassanakajon A, Krusong K. Role of Clathrin Assembly Protein-2 Beta Subunit during White Spot Syndrome Virus Infection in Black Tiger Shrimp Penaeus monodon. Sci Rep 2019; 9:13489. [PMID: 31530841 PMCID: PMC6748913 DOI: 10.1038/s41598-019-49852-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 09/02/2019] [Indexed: 02/06/2023] Open
Abstract
White spot syndrome virus (WSSV) is one of the most lethal viruses severely affecting shrimp industry. This disease can cause 100% mortality of farmed shrimp within a week. This work aims to characterize clathrin assembly proteins in Penaeus monodon and investigate their roles in WSSV entry. In general, clathrin assembly proteins form complexes with specific receptors and clathrins, leading to clathrin-mediated endocytosis. Adaptor protein 2 (AP-2), which is responsible for endocytosis at plasma membrane, consists of four subunits including α, β2, μ2 and σ2. Knockdown of clathrin coat AP17, or σ subunit of AP-2 dramatically reduced WSSV infectivity. Similar results were observed, when shrimp were pre-treated with chlorpromazine (CPZ), an inhibitor of clathrin-dependent endocytosis. The complete open reading frames of AP-2β and μ subunits of P. monodon are reported. PmAP-2 β was up-regulated about 4-fold at 6 and 36 h post-WSSV infection. Knockdown of PmAP-2β delayed shrimp mortality during WSSV infection, of which WSSV intermediate early 1 gene expression was also down-regulated. Immunogold-labelling and transmission electron microscopy revealed that PmAP-2β co-localized with WSSV particles at plasma membrane. In addition, PmAP-2β-silencing significantly affected the expression levels of PmSTAT, PmDOME, PmDorsal and ALFPm3 during WSSV infection. It is possible that PmAP-2β is associated with the JAK/STAT and the Toll pathway.
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Affiliation(s)
- Thapanan Jatuyosporn
- Structural and Computational Biology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Pasunee Laohawutthichai
- Structural and Computational Biology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Premruethai Supungul
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, 12120, Thailand
| | - Rogerio R Sotelo-Mundo
- Laboratorio de Estructura Biomolecular, Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Carretera Gustavo Enrique Astiazaran Rosas No. 46, Hermosillo, Sonora, 83304, Mexico
| | - Adrian Ochoa-Leyva
- Departamentos de Microbiología Molecular, Medicina Molecular y Bioprocesos, Unidad Universitaria de Secuenciacián Masiva y Bioinformática, Instituto de Biotecnología (IBT), Universidad Nacional Autónoma de México (UNAM), Avenida Universidad 2001, Colonia Chamilpa, Cuernavaca, 62210, Mexico
| | - Anchalee Tassanakajon
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Kuakarun Krusong
- Structural and Computational Biology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
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de León P, Bustos MJ, Torres E, Cañas-Arranz R, Sobrino F, Carrascosa AL. Inhibition of Porcine Viruses by Different Cell-Targeted Antiviral Drugs. Front Microbiol 2019; 10:1853. [PMID: 31474954 PMCID: PMC6702965 DOI: 10.3389/fmicb.2019.01853] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/26/2019] [Indexed: 01/01/2023] Open
Abstract
Antiviral compounds targeting cellular metabolism instead of virus components have become an interesting issue for preventing and controlling the spread of virus infection, either as sole treatment or as a complement of vaccination. Some of these compounds are involved in the control of lipid metabolism and/or membrane rearrangements. Here, we describe the effect of three of these cell-targeting antivirals: lauryl gallate (LG), valproic acid (VPA), and cerulenin (CRL) in the multiplication of viruses causing important porcine diseases. The results confirm the antiviral action in cultured cells of LG against African swine fever virus (ASFV), foot and mouth disease virus (FMDV), vesicular stomatitis virus (VSV), and swine vesicular disease virus (SVDV), as well as the inhibitory effect of VPA and CRL on ASFV infection. Other gallate esters have been also assayed for their inhibition of FMDV growth. The combined action of these antivirals has been also tested in ASFV infections, with some synergistic effects when LG and VPA were co-administered. Regarding the mode of action of the antivirals, experiments on the effect of the time of its addition in infected cell cultures indicated that the inhibition by VPA and CRL occurred at early times after ASFV infection, while LG inhibited a late step in FMDV infection. In all the cases, the presence of the antiviral reduced or abolished the induction of virus-specific proteins. Interestingly, LG also reduced mortality and FMDV load in a mouse model. The possible use of cell-targeted antivirals against porcine diseases is discussed.
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Affiliation(s)
- Patricia de León
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - María José Bustos
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Elisa Torres
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Rodrigo Cañas-Arranz
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Francisco Sobrino
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Angel L Carrascosa
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
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Mechanisms of Entry and Endosomal Pathway of African Swine Fever Virus. Vaccines (Basel) 2017; 5:vaccines5040042. [PMID: 29117102 PMCID: PMC5748609 DOI: 10.3390/vaccines5040042] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 10/19/2017] [Accepted: 10/31/2017] [Indexed: 02/06/2023] Open
Abstract
African Swine Fever Virus (ASFV) causes a serious swine disease that is endemic in Africa and Sardinia and presently spreading in Russia and neighboring countries, including Poland and recently, the Czech Republic. This uncontrolled dissemination is a world-wide threat, as no specific protection or vaccine is available. ASFV is a very complex icosahedral, enveloped virus about 200 nm in diameter, which infects several members of pigs. The virus enters host cells by receptor-mediated endocytosis that depends on energy, vacuolar pH and temperature. The specific receptor(s) and attachment factor(s) involved in viral entry are still unknown, although macropinocytosis and clathrin-dependent mechanisms have been proposed. After internalization, ASFV traffics through the endolysosomal system. The capsid and inner envelope are found in early endosomes or macropinosomes early after infection, colocalizing with EEA1 and Rab5, while at later times they co-localize with markers of late endosomes and lysosomes, such as Rab7 or Lamp 1. A direct relationship has been established between the maturity of the endosomal pathway and the progression of infection in the cell. Finally, ASFV uncoating first involves the loss of the outer capsid layers, and later fusion of the inner membrane with endosomes, releasing the nude core into the cytosol.
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Phenotyping and susceptibility of established porcine cells lines to African Swine Fever Virus infection and viral production. Sci Rep 2017; 7:10369. [PMID: 28871180 PMCID: PMC5583235 DOI: 10.1038/s41598-017-09948-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 08/01/2017] [Indexed: 02/07/2023] Open
Abstract
African swine fever virus (ASFV) is a highly pathogenic, double-stranded DNA virus with a marked tropism for cells of the monocyte-macrophage lineage, affecting swine species and provoking severe economic losses and health threats. In the present study, four established porcine cell lines, IPAM-WT, IPAM-CD163, C∆2+ and WSL, were compared to porcine alveolar macrophage (PAM) in terms of surface marker phenotype, susceptibility to ASFV infection and virus production. The virulent ASFV Armenia/07, E70 or the naturally attenuated NHV/P68 strains were used as viral models. Cells expressed only low levels of specific receptors linked to the monocyte/macrophage lineage, with low levels of infection overall, with the exception of WSL, which showed more efficient production of strain NHV/P68 but not of strains E70 and Armenia/07.
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10
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Zakaryan H, Revilla Y. African swine fever virus: current state and future perspectives in vaccine and antiviral research. Vet Microbiol 2016; 185:15-9. [DOI: 10.1016/j.vetmic.2016.01.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 01/19/2016] [Accepted: 01/22/2016] [Indexed: 01/09/2023]
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Galindo I, Cuesta-Geijo MA, Hlavova K, Muñoz-Moreno R, Barrado-Gil L, Dominguez J, Alonso C. African swine fever virus infects macrophages, the natural host cells, via clathrin- and cholesterol-dependent endocytosis. Virus Res 2015; 200:45-55. [PMID: 25662020 DOI: 10.1016/j.virusres.2015.01.022] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 01/21/2015] [Accepted: 01/23/2015] [Indexed: 11/29/2022]
Abstract
The main cellular target for African swine fever virus (ASFV) is the porcine macrophage. However, existing data about the early phases of infection were previously characterized in non-leukocyte cells such as Vero cells. Here, we report that ASFV enters the natural host cell using dynamin-dependent and clathrin-mediated endocytosis. This pathway is strongly pH-dependent during the first steps of infection in porcine macrophages. We investigated the effect of drugs inhibiting several endocytic pathways in macrophages and compared ASFV with vaccinia virus (VV), which apparently involves different entry pathways. The presence of cholesterol in cellular membranes was found to be essential for a productive ASFV infection while actin-dependent endocytosis and the participation of phosphoinositide-3-kinase (PI3K) activity were other cellular factors required in the process of viral entry. These findings improved our understanding of the ASFV interactions with macrophages that allow for successful viral replication.
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Affiliation(s)
- Inmaculada Galindo
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain.
| | - Miguel Angel Cuesta-Geijo
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain.
| | - Karolina Hlavova
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain.
| | - Raquel Muñoz-Moreno
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain.
| | - Lucía Barrado-Gil
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain.
| | - Javier Dominguez
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain.
| | - Covadonga Alonso
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain.
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Jatuyosporn T, Supungul P, Tassanakajon A, Krusong K. The essential role of clathrin-mediated endocytosis in yellow head virus propagation in the black tiger shrimp Penaeus monodon. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 44:100-110. [PMID: 24333440 DOI: 10.1016/j.dci.2013.11.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 11/25/2013] [Accepted: 11/26/2013] [Indexed: 06/03/2023]
Abstract
Yellow head virus (YHV) is one of the most widespread viruses seriously affecting black tiger shrimp (Penaeus monodon) cultivation. A previous microarray study demonstrated that clathrin coat assembly protein 17 (AP17) was significantly up-regulated after YHV infection (Pongsomboon et al., 2011). Clathrin coat AP17 is a part of the assembly protein σ2 (AP-2) complex which is involved in clathrin-mediated endocytosis. Quantitative RT-PCR (qRT-PCR) revealed that the clathrin coat AP17 gene was up-regulated 3-fold at 12 h post YHV infection. In addition, immunofluorescence microscopy showed that clathrin coat AP17 was highly expressed in the cytoplasm of the YHV-infected hemocytes. Knockdown of the clathrin coat AP17 gene dramatically reduced YHV replicativity by 32-fold. Interestingly, shrimp pre-treated with chlorpromazine, a commercial drug that inhibits clathrin-dependent endocytosis, exhibited significantly low levels of YHV infection. Taken together, these results suggest that clathrin-mediated endocytosis is involved in YHV propagation in P. monodon.
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Affiliation(s)
- Thapanan Jatuyosporn
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Premruethai Supungul
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani 12120, Thailand
| | - Anchalee Tassanakajon
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Kuakarun Krusong
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
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Fasina FO, Olaokun OO, Oladipo OO, Fasina MM, Makinde AA, Heath L, Bastos ADS. Phytochemical analysis and in-vitro anti-African swine fever virus activity of extracts and fractions of Ancistrocladus uncinatus, Hutch and Dalziel (Ancistrocladaceae). BMC Vet Res 2013; 9:120. [PMID: 23777548 PMCID: PMC3694037 DOI: 10.1186/1746-6148-9-120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 06/10/2013] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND African swine fever (ASF), a highly contagious fatal acute haemorrhagic viral disease of pigs currently has no treatment or vaccination protocol and it threatens the pig industry worldwide. Recent outbreaks were managed by farmers with ethnoveterinary preparations with various claims of effectiveness. RESULTS We identified 35 compounds using GC-MS protocol and ASF virus (NIG 99) was significantly reduced by some extracts and fractions of the plant. However, the plant was poorly extracted by water and cytotoxicity was found to be a major problem with the use of the plant since its extracts also reduced the primary cells used in the assay. CONCLUSION It is confirmed that the plant has antiviral potentials against ASF virus and farmers' claims seem to have certain degree of veracity, but finding the best means of exploring the potential of the plant while reducing its cytotoxic effect in-vitro and in-vivo will be necessary.
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Affiliation(s)
- Folorunso O Fasina
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Oyinlola O Olaokun
- Phytomedicine Programme, Department of Paraclinical Science, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa
| | | | - Margaret M Fasina
- Maximum Farms, P. O. Box 23, Vom Post Office, Plateau State, Nigeria
| | | | - Livio Heath
- Transboundary Animal Disease Programme, ARC-Onderstepoort Veterinary Institute, Onderstepoort, South Africa
| | - Armanda DS Bastos
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
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14
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Netherton CL, Wileman TE. African swine fever virus organelle rearrangements. Virus Res 2013; 173:76-86. [PMID: 23291273 DOI: 10.1016/j.virusres.2012.12.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 11/30/2012] [Accepted: 12/03/2012] [Indexed: 11/28/2022]
Abstract
Like most viruses African swine fever virus (ASFV) subsumes the host cell apparatus in order to facilitate its replication. ASFV replication is a highly orchestrated process with a least four stages of transcription, immediate-early, early, intermediate and late. As the infective cycle progresses through these stages most if not all of the organelles that comprise a nucleated cell are modified, adapted or in some cases destroyed. The entry of the virus is receptor-mediated, but the precise mechanism of endocytosis is a matter of keen, current debate. Once ASFV has exited from the endosomal-lysosomal complex the virus life-cycle enters into an intimate relationship with the microtubular network. Genome replication is believed to be initiated within the nucleus and ASFV infection completely reorders the structure of this organelle. The majority of replication and assembly occurs in discrete, perinuclear regions of the cell called virus factories and finally progeny virions are transported to the plasma membrane along microtubules where they bud out or are propelled away along actin projections to infect new cells. The generation of ASFV replication sites induces profound reorganisation of the organelles that comprise the secretory pathway and may contribute to the induction of cellular stress responses that ASFV modulates. The level of organisation and complexity of virus factories are not dissimilar to those seen in cellular organelles. Like their cellular counterparts the formation of virus factories, as well as virus entry and exit, are dependent on the various components of the cytoskeleton. This review will summarise these rearrangements, the viral proteins involved and their functional consequences.
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Affiliation(s)
- Christopher L Netherton
- Vaccinology Group, The Pirbright Institute, Pirbright, Woking, Surrey GU24 0NF, United Kingdom.
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15
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Alonso C, Galindo I, Cuesta-Geijo MA, Cabezas M, Hernaez B, Muñoz-Moreno R. African swine fever virus-cell interactions: from virus entry to cell survival. Virus Res 2012; 173:42-57. [PMID: 23262167 PMCID: PMC7114420 DOI: 10.1016/j.virusres.2012.12.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 12/01/2012] [Accepted: 12/04/2012] [Indexed: 11/28/2022]
Abstract
Viruses have adapted to evolve complex and dynamic interactions with their host cell. The viral entry mechanism determines viral tropism and pathogenesis. The entry of African swine fever virus (ASFV) is dynamin-dependent and clathrin-mediated, but other pathways have been described such as macropinocytosis. During endocytosis, ASFV viral particles undergo disassembly in various compartments that the virus passes through en route to the site of replication. This disassembly relies on the acid pH of late endosomes and on microtubule cytoskeleton transport. ASFV interacts with several regulatory pathways to establish an optimal environment for replication. Examples of these pathways include small GTPases, actin-related signaling, and lipid signaling. Cellular cholesterol, the entire cholesterol biosynthesis pathway, and phosphoinositides are central molecular networks required for successful infection. Here we report new data on the conformation of the viral replication site or viral factory and the remodeling of the subcellular structures. We review the virus-induced regulation of ER stress, apoptosis and autophagy as key mechanisms of cell survival and determinants of infection outcome. Finally, future challenges for the development of new preventive strategies against this virus are proposed on the basis of current knowledge about ASFV-host interactions.
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Affiliation(s)
- Covadonga Alonso
- Dpto. de Biotecnología, INIA, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Ctra. de Coruña Km 7.5, 28040 Madrid, Spain.
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16
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African swine fever virus uses macropinocytosis to enter host cells. PLoS Pathog 2012; 8:e1002754. [PMID: 22719252 PMCID: PMC3375293 DOI: 10.1371/journal.ppat.1002754] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 04/30/2012] [Indexed: 12/16/2022] Open
Abstract
African swine fever (ASF) is caused by a large and highly pathogenic DNA virus, African swine fever virus (ASFV), which provokes severe economic losses and expansion threats. Presently, no specific protection or vaccine against ASF is available, despite the high hazard that the continued occurrence of the disease in sub-Saharan Africa, the recent outbreak in the Caucasus in 2007, and the potential dissemination to neighboring countries, represents. Although virus entry is a remarkable target for the development of protection tools, knowledge of the ASFV entry mechanism is still very limited. Whereas early studies have proposed that the virus enters cells through receptor-mediated endocytosis, the specific mechanism used by ASFV remains uncertain. Here we used the ASFV virulent isolate Ba71, adapted to grow in Vero cells (Ba71V), and the virulent strain E70 to demonstrate that entry and internalization of ASFV includes most of the features of macropinocytosis. By a combination of optical and electron microscopy, we show that the virus causes cytoplasm membrane perturbation, blebbing and ruffles. We have also found that internalization of the virions depends on actin reorganization, activity of Na+/H+ exchangers, and signaling events typical of the macropinocytic mechanism of endocytosis. The entry of virus into cells appears to directly stimulate dextran uptake, actin polarization and EGFR, PI3K-Akt, Pak1 and Rac1 activation. Inhibition of these key regulators of macropinocytosis, as well as treatment with the drug EIPA, results in a considerable decrease in ASFV entry and infection. In conclusion, this study identifies for the first time the whole pathway for ASFV entry, including the key cellular factors required for the uptake of the virus and the cell signaling involved. ASFV is a highly pathogenic zoonotic virus, which can cause severe economic losses and bioterrorism threats. No vaccine against ASFV is available so far. A strong hazard of ASFV dissemination through EU countries from Caucasian areas has recently emerged, thus making urgent to acquire knowledge and tools for protection against this virus. Despite that, our understanding of how ASFV enters host cells is very limited. A thorough understanding of this process would enable to design targeted antiviral therapies and vaccine development. The present study clearly defines key steps of ASFV cellular uptake, as well as the host factors responsible for permitting virus entry into cells. Our results indicate that the primary mechanism of ASFV uptake is a macropinocytosis-like process, that involves cellular membrane perturbation, actin polarization, activity of Na+/H+ membrane channels, and signaling proceedings typical of the macropinocytic mechanism of endocytosis, such as Rac1-Pak1 pathways, PI3K and tyrosine-kinases activation. These findings help understanding how ASFV infects cells and suggest that disturbance of macropinocytosis may be useful in the impairment of infection and vaccine development.
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17
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Small rho GTPases and cholesterol biosynthetic pathway intermediates in African swine fever virus infection. J Virol 2011; 86:1758-67. [PMID: 22114329 DOI: 10.1128/jvi.05666-11] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The integrity of the cholesterol biosynthesis pathway is required for efficient African swine fever virus (ASFV) infection. Incorporation of prenyl groups into Rho GTPases plays a key role in several stages of ASFV infection, since both geranylgeranyl and farnesyl pyrophosphates are required at different infection steps. We found that Rho GTPase inhibition impaired virus morphogenesis and resulted in an abnormal viral factory size with the accumulation of envelope precursors and immature virions. Furthermore, abundant defective virions reached the plasma membrane, and filopodia formation in exocytosis was abrogated. Rac1 was activated at early ASFV infection stages, coincident with microtubule acetylation, a process that stabilizes microtubules for virus transport. Rac1 inhibition did not affect the viral entry step itself but impaired subsequent virus production. We found that specific Rac1 inhibition impaired viral induced microtubule acetylation and viral intracellular transport. These findings highlight that viral infection is the result of a carefully orchestrated modulation of Rho family GTPase activity within the host cell; this modulation results critical for virus morphogenesis and in turn, triggers cytoskeleton remodeling, such as microtubule stabilization for viral transport during early infection.
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18
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Abstract
African swine fever virus (ASFV) is a large DNA virus that enters host cells after receptor-mediated endocytosis and depends on acidic cellular compartments for productive infection. The exact cellular mechanism, however, is largely unknown. In order to dissect ASFV entry, we have analyzed the major endocytic routes using specific inhibitors and dominant negative mutants and analyzed the consequences for ASFV entry into host cells. Our results indicate that ASFV entry into host cells takes place by clathrin-mediated endocytosis which requires dynamin GTPase activity. Also, the clathrin-coated pit component Eps15 was identified as a relevant cellular factor during infection. The presence of cholesterol in cellular membranes, but not lipid rafts or caveolae, was found to be essential for a productive ASFV infection. In contrast, inhibitors of the Na(+)/H(+) ion channels and actin polymerization inhibition did not significantly modify ASFV infection, suggesting that macropinocytosis does not represent the main entry route for ASFV. These results suggest a dynamin-dependent and clathrin-mediated endocytic pathway of ASFV entry for the cell types and viral strains analyzed.
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19
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Mudhakir D, Harashima H. Learning from the viral journey: how to enter cells and how to overcome intracellular barriers to reach the nucleus. AAPS JOURNAL 2009; 11:65-77. [PMID: 19194803 DOI: 10.1208/s12248-009-9080-9] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Accepted: 12/24/2008] [Indexed: 02/06/2023]
Abstract
Viruses deliver their genome into host cells where they subsequently replicate and multiply. A variety of relevant strategies have evolved by which viruses gain intracellular access and utilize cellular machinery for the synthesis of their genome. Therefore, the viral journey provides insight into the cell's trafficking machinery and how it can be best exploited to improve nonviral gene delivery systems. This review summarizes viral internalization pathways and intracellular trafficking of viruses, with an emphasis on the endosomal escape processes of nonenveloped viruses. Intracellular events from viral entry through nuclear delivery of the viral complementary DNA are also discussed.
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Affiliation(s)
- Diky Mudhakir
- Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, 060-0812, Japan
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20
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Lin YL, Shiao MS, Mettling C, Chou CK. Cholesterol requirement of hepatitis B surface antigen (HBsAg) secretion. Virology 2003; 314:253-60. [PMID: 14517078 DOI: 10.1016/s0042-6822(03)00403-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Hepatitis B virus-infected patients secrete enormous quantities (50-300 microg/ml) of hepatitis B surface antigen (HBsAg) in their serum. One hypothesis for this synthetic effort is that these lipoprotein particles serve to adsorb neutralizing antisurface antibodies. We have shown that insulin suppresses the expression of HBsAg in human hepatoma cell Hep3B cells. We further studied the signaling pathway of insulin on the inhibition of HBsAg. Using a fungal metabolite, lovastatin, to block the p21Ras signaling pathway of insulin, we found that lovastatin inhibited the secretion of HBsAg into culture medium in Hep3B cells; however, the involvement of p21Ras-MAPKs was excluded in this effect. The cholesterol depletion from the membrane, leading to the destabilization of rafts, was the mechanism for the lovastatin inhibition of HBsAg secretion. However, lovastatin has no effect on the secretion of infectious viral Dane particles. Herein, we show for the first time that cholesterol is required for HBsAg secretion.
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Affiliation(s)
- Yea-Lih Lin
- Institut de Génétique Humaine, IGH-CNRS, 141, rue de la Cardonille, 34396 Montpellier Cedex 5, France.
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21
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Patel HK, Willhite DC, Patel RM, Ye D, Williams CL, Torres EM, Marty KB, MacDonald RA, Blanke SR. Plasma membrane cholesterol modulates cellular vacuolation induced by the Helicobacter pylori vacuolating cytotoxin. Infect Immun 2002; 70:4112-23. [PMID: 12117919 PMCID: PMC128184 DOI: 10.1128/iai.70.8.4112-4123.2002] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Helicobacter pylori vacuolating cytotoxin (VacA) induces the degenerative vacuolation of mammalian cells both in vitro and in vivo. Here, we demonstrate that plasma membrane cholesterol is essential for vacuolation of mammalian cells by VacA. Vacuole biogenesis in multiple cell lines was completely blocked when cholesterol was extracted selectively from the plasma membrane by using beta-cyclodextrins. Moreover, increasing plasma membrane cholesterol levels strongly potentiated VacA-induced vacuolation. In contrast, inhibiting de novo biosynthesis of cholesterol with lovastatin or compactin had no detectable effect on vacuolation. While depletion of plasma membrane cholesterol has been shown to interfere with both clathrin-mediated endocytosis and caveola-dependent endocytosis, neither of these two internalization pathways was found to be essential for vacuolation of cells by VacA. Depleting plasma membrane cholesterol attenuated the entry of VacA into HeLa cells. In addition, beta-cyclodextrin reagents blocked vacuolation of cells that were either preloaded with VacA or had VacA directly expressed within the cytosol. Collectively, our results suggest that plasma membrane cholesterol is important for both the intoxication mechanism of VacA and subsequent vacuole biogenesis.
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Affiliation(s)
- Hetal K Patel
- Department of Biology and Biochemistry, University of Houston, Texas 77204-5001, USA
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22
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Chatterjee PK, Vashishtha M, Kielian M. Biochemical consequences of a mutation that controls the cholesterol dependence of Semliki Forest virus fusion. J Virol 2000; 74:1623-31. [PMID: 10644331 PMCID: PMC111636 DOI: 10.1128/jvi.74.4.1623-1631.2000] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The enveloped alphavirus Semliki Forest virus (SFV) infects cells via a low-pH-triggered membrane fusion reaction that requires cholesterol and sphingolipid in the target membrane. Cholesterol-depleted insect cells are highly resistant to alphavirus infection and were used to select srf-3, an SFV mutant that is approximately 100-fold less cholesterol dependent for infection due to a single amino acid change in the E1 spike subunit, proline 226 to serine. Sensitive lipid-mixing assays here demonstrated that the in vitro fusion of srf-3 and wild-type (wt) virus with cholesterol-containing liposomes had comparable kinetics, activation energies, and sphingolipid dependence. In contrast, srf-3 fusion with sterol-free liposomes was significantly more efficient than that of wt virus. Thus, the srf-3 mutation does not affect its general fusion properties with purified lipid bilayers but causes a marked and specific reduction in cholesterol dependence. Upon exposure to low pH, the E1 spike subunit undergoes distinct conformational changes, resulting in the exposure of an acid conformation-specific epitope and formation of an E1 homotrimer. These conformational changes were strongly cholesterol and sphingolipid dependent for wt SFV and strikingly less cholesterol dependent for srf-3. Our results thus demonstrate the functional importance of fusogenic E1 conformational changes in the control of SFV cholesterol dependence.
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Affiliation(s)
- P K Chatterjee
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Kielian M, Chatterjee PK, Gibbons DL, Lu YE. Specific roles for lipids in virus fusion and exit. Examples from the alphaviruses. Subcell Biochem 2000; 34:409-55. [PMID: 10808340 DOI: 10.1007/0-306-46824-7_11] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Affiliation(s)
- M Kielian
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Abstract
Until recently, the only risk factors implicated in noninherited cases of Alzheimer's disease were increasing age, Down's syndrome, and probably, head injury. Having found that herpes simplex type 1 virus (HSV1) is present in the brain of many elderly people, we discovered that it is a risk factor for Alzheimer's disease when in the central nervous system of APOE-epsilon4 allele carriers. On the basis of this result and our finding that apoE-epsilon4 is a risk factor for herpes labialis, we suggested that the combination of virus and genetic factor is particularly damaging in the nervous system. The present review describes 1) the search for HSV1 in human brain; 2) HSV1 infection of the peripheral nervous system; 3) HSV1 infection of the central nervous system; 4) how APOE genotype might influence HSV1 infection; 5) possible APOE genotype effect on viral latency and its reactivation; 6) interactions of viruses with lipoproteins, their components, and lipoprotein receptors; 7) the role of APOE in repair; 8) pathological processes in AD and their relationship to prior damage; and 9) implications for the prevention or treatment of Alzheimer's disease.
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Affiliation(s)
- C B Dobson
- Department of Optometry and Neuroscience, University of Manchester Institute of Science and Technology, United Kingdom
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