1
|
Zhang X, Gao P, Wang L, Liu L, Wang Q, Xu Z, Zhang Y, Yu Y, Ma J. ADP-ribosylation factor 6 promotes infectious bursal disease virus replication by affecting the internalization process via clathrin. Vet Microbiol 2024; 290:109989. [PMID: 38266371 DOI: 10.1016/j.vetmic.2024.109989] [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: 08/31/2023] [Revised: 01/05/2024] [Accepted: 01/08/2024] [Indexed: 01/26/2024]
Abstract
ADP-ribosylation factor 6 (ARF6) is a small G protein with extensive functions, including regulation of cellular membrane transport and viral infection. Infectious bursal disease (IBD) is caused by infectious bursal disease virus (IBDV), which mainly invades the bursa of Fabricius and causes low immunity in poultry. Our study demonstrated that IBDV infection could promote the expression of ARF6; however, the underlying mechanism remains unclear. Herein, the function of ARF6 in IBDV infection was explored, and it was revealed that viral replication was significantly promoted by ARF6 overexpression and hampered by siRNA-mediated inhibition of ARF6. Using two site mutants of ARF6 (ARF6-T27N and ARF6-Q67L), we found that IBDV replication was repressed by ARF6-T27N, indicating that ARF6 promotes IBDV replication. Further exploration of its mechanism revealed that ARF6 affects the copy number of IBDVs entering cells. A clathrin inhibitor (pitstop 2) impeded the early replication of IBDV, even when ARF6 was overexpressed. These results indicated that ARF6 promotes viral replication by affecting the internalization of IBDV, which may involve clathrin-dependent endocytosis. Our findings improve the understanding of the processes governing IBDV infection and provide insights into its prevention and control.
Collapse
Affiliation(s)
- Xinxin Zhang
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, Henan, PR China; Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping, Lanzhou 730046, PR China
| | - Pei Gao
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, Henan, PR China
| | - Li Wang
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, Henan, PR China
| | - Liu Liu
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, Henan, PR China
| | - Qiuxia Wang
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, Henan, PR China
| | - Zhiyong Xu
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, Henan, PR China
| | - Yanhong Zhang
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, Henan, PR China
| | - Yan Yu
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, Henan, PR China
| | - Jinyou Ma
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, Henan, PR China.
| |
Collapse
|
2
|
Moreno de Lara L, Werner A, Borchers A, Carrillo-Salinas FJ, Marmol W, Parthasarathy S, Iyer V, Vogell A, Illanes D, Abadía-Molina AC, Ochsenbauer C, Wira CR, Rodriguez-Garcia M. Aging dysregulates neutrophil extracellular trap formation in response to HIV in blood and genital tissues. Front Immunol 2023; 14:1256182. [PMID: 38035114 PMCID: PMC10684664 DOI: 10.3389/fimmu.2023.1256182] [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: 07/11/2023] [Accepted: 10/27/2023] [Indexed: 12/02/2023] Open
Abstract
Women acquire HIV through sexual transmission, with increasing incidence in women >50 years old. Identifying protective mechanisms in the female genital tract (FGT) is important to prevent HIV-acquisition in women as they age. Human genital and blood neutrophils inactivate HIV by releasing neutrophil extracellular traps (NETs), an innate protective mechanism against HIV-infection. However, how NET formation is triggered by HIV in different tissues and whether this mechanism is affected by aging remain unknown. We demonstrate that the mechanisms that trigger NET release in response to HIV are different in blood and genital tissues, and that NET release decreases with aging. In blood neutrophils, HIV stimulation independently activated calcium pathways and endosomal TLR8, but aging reduced calcium responses, resulting in delayed NET release. In contrast, calcium responses were absent in genital neutrophils and NET release was triggered preferentially through TLR8 activation, but aging impaired this pathway. HIV induced NET formation through non-lytic pathways in blood and FGT neutrophils, except for a small subset of NETs that incorporated annexin V and lactoferrin predominantly in blood, suggesting proinflammatory and lytic NET release. Our findings demonstrate that blood neutrophils cannot model genital neutrophil responses which has important implications to understanding protection against HIV acquisition.
Collapse
Affiliation(s)
- Laura Moreno de Lara
- Department of Immunology, Tufts University School of Medicine, Boston, MA, United States
- Instituto de Biopatología y Medicina Regenerativa, Centro de Investigación Biomédica, Universidad de Granada, Granada, Spain
| | - Alexandra Werner
- Department of Immunology, Tufts University School of Medicine, Boston, MA, United States
| | - Anna Borchers
- Department of Immunology, Tufts University School of Medicine, Boston, MA, United States
| | | | - Wendelin Marmol
- Program in Genetics, Molecular, and Cellular Biology, Tufts University School of Medicine, Boston, MA, United States
| | | | - Vidya Iyer
- Department of Gynecology and Obstetrics, Tufts Medical Center, Boston, MA, United States
| | - Alison Vogell
- Department of Gynecology and Obstetrics, Tufts Medical Center, Boston, MA, United States
| | - Diego Illanes
- Department of Gynecology and Obstetrics, Tufts Medical Center, Boston, MA, United States
| | - Ana C. Abadía-Molina
- Instituto de Biopatología y Medicina Regenerativa, Centro de Investigación Biomédica, Universidad de Granada, Granada, Spain
- Departamento de Bioquímica y Biología Molecular 3 e Inmunología, Universidad de Granada, Granada, Spain
| | - Christina Ochsenbauer
- Department of Medicine and UAB Center for AIDS Research, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Charles R. Wira
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
| | - Marta Rodriguez-Garcia
- Department of Immunology, Tufts University School of Medicine, Boston, MA, United States
| |
Collapse
|
3
|
Tavares LA, Januário YC, daSilva LLP. HIV-1 Hijacking of Host ATPases and GTPases That Control Protein Trafficking. Front Cell Dev Biol 2021; 9:622610. [PMID: 34307340 PMCID: PMC8295591 DOI: 10.3389/fcell.2021.622610] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 06/07/2021] [Indexed: 12/22/2022] Open
Abstract
The human immunodeficiency virus (HIV-1) modifies the host cell environment to ensure efficient and sustained viral replication. Key to these processes is the capacity of the virus to hijack ATPases, GTPases and the associated proteins that control intracellular protein trafficking. The functions of these energy-harnessing enzymes can be seized by HIV-1 to allow the intracellular transport of viral components within the host cell or to change the subcellular distribution of antiviral factors, leading to immune evasion. Here, we summarize how energy-related proteins deviate from their normal functions in host protein trafficking to aid the virus in different phases of its replicative cycle. Recent discoveries regarding the interplay among HIV-1 and host ATPases and GTPases may shed light on potential targets for pharmacological intervention.
Collapse
Affiliation(s)
- Lucas A Tavares
- Department of Cell and Molecular Biology, Center for Virology Research, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Yunan C Januário
- Department of Cell and Molecular Biology, Center for Virology Research, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Luis L P daSilva
- Department of Cell and Molecular Biology, Center for Virology Research, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| |
Collapse
|
4
|
Benarroch Y, Juttukonda L, Sabharwal V, Boateng J, Khan AR, Yarrington C, Wachman EM, Taglauer E. Differential Expression of Rab5 and Rab7 Small GTPase Proteins in Placental Tissues From Pregnancies Affected by Maternal Coronavirus Disease 2019. Clin Ther 2021; 43:308-318. [PMID: 33541739 PMCID: PMC7837084 DOI: 10.1016/j.clinthera.2021.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/03/2021] [Accepted: 01/04/2021] [Indexed: 12/26/2022]
Abstract
Purpose The majority of pregnancies affected by maternal coronavirus disease 2019 (COVID-19) do not result in fetal transmission. However, several studies have identified parenchymal changes in their placental tissues, suggesting a placental response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the maternal–fetal interface. Although many COVID-19 placental studies have focused on the expression of the canonical SARS-CoV-2 entry proteins angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2, further characterization of subcellular molecules involved in viral trafficking have not yet been investigated in these tissues. Of interest are Rab proteins, a family of small GTPase proteins that direct intracellular transport between different endocytic organelles. Rab5 and Rab7 in particular have previously been implicated in HIV and cytomegalovirus invasion of placental trophoblast cells in vitro; the localization of these molecules has not been fully characterized within the human maternal–fetal interface, however, or within placental tissues from SARS-CoV-2–infected pregnancies. Methods Using fluorescent immunohistochemistry, Rab5 and Rab7 placental localization and comparative fluorescence intensity were explored in a cohort of placental tissues from pregnancies affected by maternal COVID-19 disease (COVID, n = 15) compared with contemporary control subjects (Control, n = 10). Fluorescence intensity was quantified by using corrected total cell fluorescence values. Findings Within placental villi, Rab5 was consistently localized in syncytiotrophoblast and cytotrophoblast cells. Rab5 had significantly higher mean (SEM) fluorescence intensity in the COVID cohort (Control, 1.96 [0.16]; COVID, 2.62 [0.09]; P = 0.0014). In contrast, although Rab7 was also localized within placental villous syncytiotrophoblast and cytotrophoblast cells, mean (SEM) Rab7 fluorescence intensity was significantly downregulated in COVID vs Control placentas (Control, 35.9 [4.1]; COVID, 20.1 [0.52]; P = 0.0001). Implications This differential expression of Rab5 and Rab7 suggests that placental endocytic pathways may be altered at the maternal–fetal interface in pregnancies affected by maternal SARS-CoV-2 infection. As key molecules governing intracellular vesicle transport, including viral trafficking, Rab GTPase proteins may be of interest for ongoing studies examining placental responses to COVID-19 in pregnancy.
Collapse
Affiliation(s)
| | - Lillian Juttukonda
- Boston Combined Residency Program in Pediatrics, Boston Medical Center and Children's Hospital Boston, Boston, MA, USA
| | | | - Jeffery Boateng
- Department of Pediatrics, Boston Medical Center, Boston, MA, USA
| | - Amir R Khan
- Division of Newborn Medicine, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA; School of Biochemistry and Immunology, Trinity College, Dublin, Ireland
| | | | - Elisha M Wachman
- Department of Pediatrics, Boston Medical Center, Boston, MA, USA
| | - Elizabeth Taglauer
- Department of Pediatrics, Boston Medical Center, Boston, MA, USA; Division of Newborn Medicine, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA.
| |
Collapse
|
5
|
Wang L, Li C, Zhang X, Yang M, Wei S, Huang Y, Qin Q, Wang S. The Small GTPase Rab5c Exerts Bi-Function in Singapore Grouper Iridovirus Infections and Cellular Responses in the Grouper, Epinephelus coioides. Front Immunol 2020; 11:2133. [PMID: 33013900 PMCID: PMC7495150 DOI: 10.3389/fimmu.2020.02133] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 08/06/2020] [Indexed: 02/04/2023] Open
Abstract
The small GTPase Rab5 is one of the master regulators of vesicular trafficking that participates in early stages of the endocytic pathway, such as endocytosis and endosome maturation. Three Rab5 isoforms (a, b, and c) share high sequence identity, and exhibit complex functions. However, the role of Rab5c in virus infection and cellular immune responses remains poorly understood. In this study, based on the established virus-cell infection model, Singapore grouper iridovirus (SGIV)-infected grouper spleen (GS) cells, we investigated the role of Rab5c in virus infection and host immune responses. Rab5c was cloned from the orange-spotted grouper, Epinephelus coioides, and termed EcRab5c. EcRab5c encoded a 220-amino-acid polypeptide, showing 99% and 91% identity to Anabas testudineus, and Homo sapiens, respectively. Confocal imaging showed that EcRab5c localized as punctate structures in the cytoplasm. However, a constitutively active (CA) EcRab5c mutant led to enlarged vesicles, while a dominant negative (DN) EcRab5c mutant reduced vesicle structures. EcRab5c expression levels were significantly increased after SGIV infection. EcRab5c knockdown, or CA/DN EcRab5c overexpression significantly inhibited SGIV infection. Using single-particle imaging analysis, we further observed that EcRab5c disruption impaired crucial events at the early stage of SGIV infection, including virus binding, entry, and transport from early to late endosomes, at the single virus level. Furthermore, it is the first time to investigate that EcRab5c is required in autophagy. Equally, EcRab5c positively regulated interferon-related factors and pro-inflammatory cytokines. In summary, these data showed that EcRab5c exerted a bi-functional role on iridovirus infection and host immunity in fish, which furthers our understanding of virus and host immune interactions.
Collapse
Affiliation(s)
- Liqun Wang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Chen Li
- College of Fisheries, Henan Normal University, Xinxiang, China
| | - Xinyue Zhang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Min Yang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Shina Wei
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Youhua Huang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Qiwei Qin
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Shaowen Wang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| |
Collapse
|
6
|
The Small GTPase Arf6: An Overview of Its Mechanisms of Action and of Its Role in Host⁻Pathogen Interactions and Innate Immunity. Int J Mol Sci 2019; 20:ijms20092209. [PMID: 31060328 PMCID: PMC6539230 DOI: 10.3390/ijms20092209] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/26/2019] [Accepted: 04/27/2019] [Indexed: 12/15/2022] Open
Abstract
The small GTase Arf6 has several important functions in intracellular vesicular trafficking and regulates the recycling of different types of cargo internalized via clathrin-dependent or -independent endocytosis. It activates the lipid modifying enzymes PIP 5-kinase and phospholipase D, promotes actin polymerization, and affects several functionally distinct processes in the cell. Arf6 is used for the phagocytosis of pathogens and can be directly or indirectly targeted by various pathogens to block phagocytosis or induce the uptake of intracellular pathogens. Arf6 is also used in the signaling of Toll-like receptors and in the activation of NADPH oxidases. In this review, we first give an overview of the different roles and mechanisms of action of Arf6 and then focus on its role in innate immunity and host–pathogen interactions.
Collapse
|
7
|
León-Juárez M, Martínez–Castillo M, González-García LD, Helguera-Repetto AC, Zaga-Clavellina V, García-Cordero J, Flores-Pliego A, Herrera-Salazar A, Vázquez-Martínez ER, Reyes-Muñoz E. Cellular and molecular mechanisms of viral infection in the human placenta. Pathog Dis 2017; 75:4056146. [PMID: 28903546 PMCID: PMC7108519 DOI: 10.1093/femspd/ftx093] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 07/27/2017] [Indexed: 12/22/2022] Open
Abstract
The placenta is a highly specialized organ that is formed during human gestation for conferring protection and generating an optimal microenvironment to maintain the equilibrium between immunological and biochemical factors for fetal development. Diverse pathogens, including viruses, can infect several cellular components of the placenta, such as trophoblasts, syncytiotrophoblasts and other hematopoietic cells. Viral infections during pregnancy have been associated with fetal malformation and pregnancy complications such as preterm labor. In this minireview, we describe the most recent findings regarding virus-host interactions at the placental interface and investigate the mechanisms through which viruses may access trophoblasts and the pathogenic processes involved in viral dissemination at the maternal-fetal interface.
Collapse
Affiliation(s)
- Moises León-Juárez
- Departamento de Inmunobioquímica, Instituto Nacional de Perinatología “Isidro Espinosa de los Reyes”, Montes Urales 800, Col. Lomas Virreyes, CP 11000, Ciudad de México, México
| | - Macario Martínez–Castillo
- Departamento de Inmunobioquímica, Instituto Nacional de Perinatología “Isidro Espinosa de los Reyes”, Montes Urales 800, Col. Lomas Virreyes, CP 11000, Ciudad de México, México
| | - Luis Didier González-García
- Departamento de Inmunobioquímica, Instituto Nacional de Perinatología “Isidro Espinosa de los Reyes”, Montes Urales 800, Col. Lomas Virreyes, CP 11000, Ciudad de México, México
| | - Addy Cecilia Helguera-Repetto
- Departamento de Inmunobioquímica, Instituto Nacional de Perinatología “Isidro Espinosa de los Reyes”, Montes Urales 800, Col. Lomas Virreyes, CP 11000, Ciudad de México, México
| | - Verónica Zaga-Clavellina
- Departamento de Inmunobioquímica, Instituto Nacional de Perinatología “Isidro Espinosa de los Reyes”, Montes Urales 800, Col. Lomas Virreyes, CP 11000, Ciudad de México, México
| | - Julio García-Cordero
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del I.P.N. Av. I.P.N 2508 Col. San Pedro Zacatenco, CP 07360 Ciudad de México, México
| | - Arturo Flores-Pliego
- Departamento de Inmunobioquímica, Instituto Nacional de Perinatología “Isidro Espinosa de los Reyes”, Montes Urales 800, Col. Lomas Virreyes, CP 11000, Ciudad de México, México
| | - Alma Herrera-Salazar
- Departamento de Infectología e Inmunología Instituto Nacional de Perinatología “Isidro Espinosa de los Reyes”, Montes Urales #800, Col. Lomas Virreyes, CP 11000. Ciudad de México, México
| | - Edgar Ricardo Vázquez-Martínez
- Unidad de Investigación en Reproducción Humana, Instituto Nacional de Perinatología-Facultad de Química UNAM, Ciudad de México, México
| | - Enrique Reyes-Muñoz
- Coordinación de Endocrinología, Instituto Nacional de Perinatología “Isidro Espinosa de los Reyes”, Montes Urales #800, Col. Lomas Virreyes, CP 11000. Ciudad de México. México
| |
Collapse
|
8
|
Rab11 family expression in the human placenta: Localization at the maternal-fetal interface. PLoS One 2017; 12:e0184864. [PMID: 28922401 PMCID: PMC5602629 DOI: 10.1371/journal.pone.0184864] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 09/03/2017] [Indexed: 11/19/2022] Open
Abstract
Rab proteins are a family of small GTPases involved in a variety of cellular processes. The Rab11 subfamily in particular directs key steps of intracellular functions involving vesicle trafficking of the endosomal recycling pathway. This Rab subfamily works through a series of effector proteins including the Rab11-FIPs (Rab11 Family-Interacting Proteins). While the Rab11 subfamily has been well characterized at the cellular level, its function within human organ systems is still being explored. In an effort to further study these proteins, we conducted a preliminary investigation of a subgroup of endosomal Rab proteins in a range of human cell lines by Western blotting. The results from this analysis indicated that Rab11a, Rab11c(Rab25) and Rab14 were expressed in a wide range of cell lines, including the human placental trophoblastic BeWo cell line. These findings encouraged us to further analyse the localization of these Rabs and their common effector protein, the Rab Coupling Protein (RCP), by immunofluorescence microscopy and to extend this work to normal human placental tissue. The placenta is a highly active exchange interface, facilitating transfer between mother and fetus during pregnancy. As Rab11 proteins are closely involved in transcytosis we hypothesized that the placenta would be an interesting human tissue model system for Rab investigation. By immunofluorescence microscopy, Rab11a, Rab11c(Rab25), Rab14 as well as their common FIP effector RCP showed prominent expression in the placental cell lines. We also identified the expression of these proteins in human placental lysates by Western blot analysis. Further, via fluorescent immunohistochemistry, we noted abundant localization of these proteins within key functional areas of primary human placental tissues, namely the outer syncytial layer of placental villous tissue and the endothelia of fetal blood vessels. Overall these findings highlight the expression of the Rab11 family within the human placenta, with novel localization at the maternal-fetal interface.
Collapse
|
9
|
Lin J, Wang C, Zhang L, Wang T, Zhang J, Liang W, Li C, Qian G, Ouyang Y, Guo K, Zhang Y. Rab5 Enhances Classical Swine Fever Virus Proliferation and Interacts with Viral NS4B Protein to Facilitate Formation of NS4B Related Complex. Front Microbiol 2017; 8:1468. [PMID: 28848503 PMCID: PMC5550665 DOI: 10.3389/fmicb.2017.01468] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 07/20/2017] [Indexed: 11/13/2022] Open
Abstract
Classical swine fever virus (CSFV) is a fatal pig pestivirus and causes serious financial losses to the pig industry. CSFV NS4B protein is one of the most important viral replicase proteins. Rab5, a member of the small Rab GTPase family, is involved in infection and replication of numerous viruses including hepatitis C virus and dengue virus. Until now, the effects of Rab5 on the proliferation of CSFV are poorly defined. In the present study, we showed that Rab5 could enhance CSFV proliferation by utilizing lentivirus-mediated constitutive overexpression and eukaryotic plasmid transient overexpression approaches. On the other hand, lentivirus-mediated short hairpin RNA knockdown of Rab5 dramatically inhibited virus production. Co-immunoprecipitation, glutathione S-transferase pulldown and laser confocal microscopy assays further confirmed the interaction between Rab5 and CSFV NS4B protein. In addition, intracellular distribution of NS4B-Red presented many granular fluorescent signals (GFS) in CSFV infected PK-15 cells. Inhibition of basal Rab5 function with Rab5 dominant negative mutant Rab5S34N resulted in disruption of the GFS. These results indicate that Rab5 plays a critical role in facilitating the formation of the NS4B related complexes. Furthermore, it was observed that NS4B co-localized with viral NS3 and NS5A proteins in the cytoplasm, suggesting that NS3 and NS5A might be components of the NS4B related complex. Taken together, these results demonstrate that Rab5 positively modulates CSFV propagation and interacts with NS4B protein to facilitate the NS4B related complexes formation.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Yanming Zhang
- College of Veterinary Medicine, Northwest A&F UniversityYangling, China
| |
Collapse
|
10
|
Rabies virus co-localizes with early (Rab5) and late (Rab7) endosomal proteins in neuronal and SH-SY5Y cells. Virol Sin 2017. [PMID: 28634871 DOI: 10.1007/s12250-017-3968-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Rabies virus (RABV) is a highly neurotropic virus that follows clathrin-mediated endocytosis and pH-dependent pathway for trafficking and invasion into endothelial cells. Early (Rab5, EEA1) and late (Rab7, LAMP1) endosomal proteins play critical roles in endosomal sorting, maturity and targeting various molecular cargoes, but their precise functions in the early stage of RABV neuronal infection remain elusive. In this study, the relationship between enigmatic entry of RABV with these endosomal proteins into neuronal and SH-SY5Y cells was investigated. Immunofluorescence, TCID50 titers, electron microscopy and western blotting were carried out to determine the molecular interaction of the nucleoprotein (N) of RABV with early or late endosomal proteins in these cell lines. The expression of N was also determined by down-regulating Rab5 and Rab7 in both cell lines through RNA interference. The results were indicative that N proficiently colocalized with Rab5/EEA1 and Rab7/LAMP1 in both cell lines at 24 and 48 h post-infection, while N titers significantly decreased in early infection of RABV. Down-regulation of Rab5 and Rab7 did not inhibit N expression, but it prevented productive infection via blocking the normal trafficking of RABV in a low pH environment. Ultrathin sections of cells studied by electron microscope also verified the close association of RABV with Rab5 and Rab7 in neurons. From the data it was concluded that primary entry of RABV strongly correlates with the kinetics of Rab-proteins present on early and late vesicles, which provides helpful clues to explain the early events of RABV in nerve cells.
Collapse
|
11
|
Ahmad W, Li Y, Guo Y, Wang X, Duan M, Guan Z, Liu Z, Zhang M. Rabies virus co-localizes with early (Rab5) and late (Rab7) endosomal proteins in neuronal and SH-SY5Y cells. Virol Sin 2017. [PMID: 28634871 DOI: 10.1007/s12250-017-3968-959:665-677,2010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
Rabies virus (RABV) is a highly neurotropic virus that follows clathrin-mediated endocytosis and pH-dependent pathway for trafficking and invasion into endothelial cells. Early (Rab5, EEA1) and late (Rab7, LAMP1) endosomal proteins play critical roles in endosomal sorting, maturity and targeting various molecular cargoes, but their precise functions in the early stage of RABV neuronal infection remain elusive. In this study, the relationship between enigmatic entry of RABV with these endosomal proteins into neuronal and SH-SY5Y cells was investigated. Immunofluorescence, TCID50 titers, electron microscopy and western blotting were carried out to determine the molecular interaction of the nucleoprotein (N) of RABV with early or late endosomal proteins in these cell lines. The expression of N was also determined by down-regulating Rab5 and Rab7 in both cell lines through RNA interference. The results were indicative that N proficiently colocalized with Rab5/EEA1 and Rab7/LAMP1 in both cell lines at 24 and 48 h post-infection, while N titers significantly decreased in early infection of RABV. Down-regulation of Rab5 and Rab7 did not inhibit N expression, but it prevented productive infection via blocking the normal trafficking of RABV in a low pH environment. Ultrathin sections of cells studied by electron microscope also verified the close association of RABV with Rab5 and Rab7 in neurons. From the data it was concluded that primary entry of RABV strongly correlates with the kinetics of Rab-proteins present on early and late vesicles, which provides helpful clues to explain the early events of RABV in nerve cells.
Collapse
Affiliation(s)
- Waqas Ahmad
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
- Section of Epidemiology and Public Health, College of Veterinary and Animal Sciences, Jhang, 35200, Pakistan
| | - Yingying Li
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Yidi Guo
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Xinyu Wang
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Ming Duan
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Zhenhong Guan
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Zengshan Liu
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Maolin Zhang
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, China.
| |
Collapse
|
12
|
Chauhan A, Tikoo A. The enigma of the clandestine association between chloroquine and HIV-1 infection. HIV Med 2015; 16:585-90. [PMID: 26238012 DOI: 10.1111/hiv.12295] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2015] [Indexed: 12/24/2022]
Abstract
OBJECTIVES The antimalarial drug chloroquine (CQ) dampens the immune system and is used in the treatment of autoimmune disorders. CQ also shows antiviral activity against nonenveloped and enveloped viruses, including HIV-1. Persistent immune activation in chronic HIV-1infection leads to CD4 T-cell depletion. CQ is envisioned to attenuate immune activation and virus activity in HIV-1-infected patients. The role of CQ in immune activation and virus activity is discussed here. METHODS To elucidate the effect of CQ on immune activation, a retrospective review of published clinical trials, in vivo experimental studies in animals, and the most relevant in vitro observations in HIV-1-infected cells, together with observations from our own laboratory studies, was carried out and the findings discussed. RESULTS In a few clinical studies and animal experiments, CQ was ineffective in decreasing immune activation and HIV-1 infection. In vitro, CQ markedly increased HIV-1 infection in astrocytes and other non-CD4 cells. CONCLUSIONS The use of CQ in HIV-1-infected patients is questionable. The evidence for a dampening of immune activation by CQ is inconclusive.
Collapse
Affiliation(s)
- A Chauhan
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC, USA
| | - A Tikoo
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC, USA
| |
Collapse
|
13
|
Ferreira VH, Dizzell S, Nazli A, Kafka JK, Mueller K, Nguyen PV, Tremblay MJ, Cochrane A, Kaushic C. Medroxyprogesterone Acetate Regulates HIV-1 Uptake and Transcytosis but Not Replication in Primary Genital Epithelial Cells, Resulting in Enhanced T-Cell Infection. J Infect Dis 2014; 211:1745-56. [PMID: 25538276 DOI: 10.1093/infdis/jiu832] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 12/17/2014] [Indexed: 12/21/2022] Open
Abstract
Although clinical and experimental evidence indicates that female sex hormones and hormonal contraceptives regulate susceptibility to human immunodeficiency virus type 1 (HIV-1) infection, the underlying mechanism remains unknown. Genital epithelial cells (GECs) are the first cells to encounter HIV during sexual transmission and their interaction with HIV may determine the outcome of exposure. This is the first report that HIV uptake by GECs increased significantly in the presence of the hormonal contraceptive medroxyprogesterone acetate (MPA) and progesterone and that uptake occurred primarily via endocytosis. No productive infection was detected, but endocytosed virus was released into apical and basolateral compartments. Significantly higher viral transcytosis was observed in the presence of MPA. In GEC and T-cell cocultures, maximum viral replication in T cells was observed in the presence of MPA, which also broadly upregulated chemokine production by GECs. These results suggest that MPA may play a significant role in regulating susceptibility to HIV.
Collapse
Affiliation(s)
- Victor H Ferreira
- Deptartment of Pathology and Molecular Medicine McMaster Immunology Research Centre, McMaster University, Hamilton
| | - Sara Dizzell
- Deptartment of Pathology and Molecular Medicine McMaster Immunology Research Centre, McMaster University, Hamilton
| | - Aisha Nazli
- Deptartment of Pathology and Molecular Medicine McMaster Immunology Research Centre, McMaster University, Hamilton
| | - Jessica K Kafka
- Deptartment of Pathology and Molecular Medicine McMaster Immunology Research Centre, McMaster University, Hamilton
| | - Kristen Mueller
- Deptartment of Pathology and Molecular Medicine McMaster Immunology Research Centre, McMaster University, Hamilton
| | - Philip V Nguyen
- Deptartment of Pathology and Molecular Medicine McMaster Immunology Research Centre, McMaster University, Hamilton
| | - Michel J Tremblay
- Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec City, Canada
| | - Alan Cochrane
- Department of Medical Genetics, University of Toronto
| | - Charu Kaushic
- Deptartment of Pathology and Molecular Medicine McMaster Immunology Research Centre, McMaster University, Hamilton
| |
Collapse
|
14
|
Barroso-González J, García-Expósito L, Puigdomènech I, de Armas-Rillo L, Machado JD, Blanco J, Valenzuela-Fernández A. Viral infection. Commun Integr Biol 2014. [DOI: 10.4161/cib.16716] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
|
15
|
Chauhan A, Tikoo A, Patel J, Abdullah AM. HIV-1 endocytosis in astrocytes: a kiss of death or survival of the fittest? Neurosci Res 2014; 88:16-22. [PMID: 25219546 DOI: 10.1016/j.neures.2014.08.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 08/14/2014] [Accepted: 08/18/2014] [Indexed: 12/23/2022]
Abstract
The brain is a target of HIV-1 and serves as an important viral reservoir. Astrocytes, the most abundant glial cell in the human brain, are involved in brain plasticity and neuroprotection. Several studies have reported HIV-1 infection of astrocytes in cell cultures and infected brain tissues. The prevailing concept is that HIV-1 infection of astrocytes leads to latent infection. Here, we provide our perspective on endocytosis-mediated HIV-1 entry and its fate in astrocytes. Natural entry of HIV-1 into astrocytes occurs via endocytosis. However, endocytosis of HIV-1 in astrocytes is a natural death trap where the majority of virus particles are degraded in endosomes and a few which escape intact lead to successful infection. Thus, regardless of artificial fine-tuning (treatment with cytokines or proinflammatory products) done to astrocytes, HIV-1 does not infect them efficiently unless the viral entry route or the endosomal enzymatic machinery has been manipulated.
Collapse
Affiliation(s)
- Ashok Chauhan
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, United States; Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29209, United States.
| | - Akshay Tikoo
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, United States
| | - Jankiben Patel
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, United States
| | - Arwa Mujahid Abdullah
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, United States
| |
Collapse
|
16
|
Chauhan A, Mehla R, Vijayakumar TS, Handy I. Endocytosis-mediated HIV-1 entry and its significance in the elusive behavior of the virus in astrocytes. Virology 2014; 456-457:1-19. [PMID: 24889220 DOI: 10.1016/j.virol.2014.03.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 01/09/2014] [Accepted: 03/04/2014] [Indexed: 11/29/2022]
Abstract
Astrocytes protect neurons but also evoke a proinflammatory response to injury and viral infections including HIV. We investigated the mechanism of HIV-1 infection in primary astrocytes, which showed minimal but productive viral infection independent of CXCR4. As with ectopic-CD4-expressing astrocytes, lysosomotropic agents led to increased HIV-1 infection in wild-type but not Rabs 5, 7, and 11-ablated astrocytes. Instead, HIV-1 infection was decreased in Rab-depleted astrocytes, corroborating viral entry by endocytosis. HIV-1 produced persistent infection in astrocytes (160 days); no evidence of latent infection was seen. Notably, one caveat is that endosomal modifiers enhanced wild-type HIV-1 infection (M- and T-tropic) in astrocytes, suggesting endocytic entry of the virus. Impeding endocytosis by inhibition of Rab 5, 7 or 11 will inhibit HIV infection in astrocytes. Although the contribution of such low-level infection in astrocytes to neurological complications is unclear, it may serve as an elusive viral reservoir in the central nervous system.
Collapse
Affiliation(s)
- Ashok Chauhan
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, USA; Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29209, USA.
| | - Rajeev Mehla
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, USA
| | | | - Indhira Handy
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, USA
| |
Collapse
|
17
|
Essential functional modules for pathogenic and defensive mechanisms in Candida albicans infections. BIOMED RESEARCH INTERNATIONAL 2014; 2014:136130. [PMID: 24757665 PMCID: PMC3976935 DOI: 10.1155/2014/136130] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 02/10/2014] [Indexed: 12/24/2022]
Abstract
The clinical and biological significance of the study of fungal pathogen Candida albicans (C. albicans) has markedly increased. However, the explicit pathogenic and invasive mechanisms of such host-pathogen interactions have not yet been fully elucidated. Therefore, the essential functional modules involved in C. albicans-zebrafish interactions were investigated in this study. Adopting a systems biology approach, the early-stage and late-stage protein-protein interaction (PPI) networks for both C. albicans and zebrafish were constructed. By comparing PPI networks at the early and late stages of the infection process, several critical functional modules were identified in both pathogenic and defensive mechanisms. Functional modules in C. albicans, like those involved in hyphal morphogenesis, ion and small molecule transport, protein secretion, and shifts in carbon utilization, were seen to play important roles in pathogen invasion and damage caused to host cells. Moreover, the functional modules in zebrafish, such as those involved in immune response, apoptosis mechanisms, ion transport, protein secretion, and hemostasis-related processes, were found to be significant as defensive mechanisms during C. albicans infection. The essential functional modules thus determined could provide insights into the molecular mechanisms of host-pathogen interactions during the infection process and thereby devise potential therapeutic strategies to treat C. albicans infection.
Collapse
|
18
|
Yingvilasprasert W, Supungul P, Tassanakajon A. PmTBC1D20, a Rab GTPase-activating protein from the black tiger shrimp, Penaeus monodon, is involved in white spot syndrome virus infection. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 42:302-310. [PMID: 24076066 DOI: 10.1016/j.dci.2013.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/18/2013] [Accepted: 09/18/2013] [Indexed: 06/02/2023]
Abstract
TBC (TRE2/BUB2/CDC16) domain proteins contain an ≈ 200-amino-acid motif and function as Rab GTPase-activating proteins that are required for regulating the activity of Rab proteins, and so, in turn, endocytic membrane trafficking in cells. TBC domain family member 20 (TBC1D20) has recently been reported to mediate Hepatitis C virus replication. Herein, PmTBC1D20 identified from the black tiger shrimp, Penaeus monodon, was characterized and evaluated for its role in white spot syndrome virus (WSSV) infection. The full-length cDNA sequence of PmTBC1D20 contains 2003 bp with a predicted 1443 bp open reading frame encoding a deduced 480 amino acid protein. Its transcript levels were significantly up-regulated at 24 and 48 h by ≈ 2.3- and 2.1-fold, respectively, after systemic infection with WSSV. In addition, depletion of PmTBC1D20 transcript in shrimps by double stranded RNA interference led to a decrease in the level of transcripts of three WSSV genes (VP28, ie1 and wsv477). This suggests the importance of PmTBC1D20 in WSSV infection. This is the first report of TBC1D20 in a crustacean and reveals the possible mechanism used by WSSV to modulate the activity of the host protein, PmTBC1D20, for its benefit in viral trafficking and replication.
Collapse
Affiliation(s)
- Wanchart Yingvilasprasert
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | | | | |
Collapse
|
19
|
Nguyen T, Robinson N, Allison SE, Coombes BK, Sad S, Krishnan L. IL-10 produced by trophoblast cells inhibits phagosome maturation leading to profound intracellular proliferation of Salmonella enterica Typhimurium. Placenta 2013; 34:765-74. [PMID: 23834952 DOI: 10.1016/j.placenta.2013.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 05/23/2013] [Accepted: 06/06/2013] [Indexed: 01/24/2023]
Abstract
INTRODUCTION Salmonella enterica Typhimurium (ST) is a phagosomal pathogen that can infect placental trophoblast cells leading to abortion and severe maternal illness. It is unclear how the trophoblast cells promote profound bacterial proliferation. METHODS The mechanism of internalization, intracellular growth and phagosomal biogenesis in ST-infected human epithelial (HeLa), macrophage (THP-1) and trophoblast-derived cell lines (JEG-3, BeWo and HTR-8) was studied. Specific inhibitors were used to block bacterial internalization. Phagosomal maturation was determined by confocal microscopy, Western-blotting and release of lysosomal β-galactosidase by infected cells. Bacterial colony forming units were determined by plating infected cell lysates on agar plates. RESULTS ST proliferated minimally in macrophages but replicated profoundly within trophoblast cells. The ST-ΔinvA (a mutant of Salmonella pathogenicity island-1 gene effector proteins) was unable to infect epithelial cells, but was internalized by scavenger receptors on trophoblasts and macrophages. However, ST was contrastingly localized in early (Rab5⁺) or late (LAMP1⁺) phagosomes within trophoblast cells and macrophages respectively. Furthermore trophoblast cells (unlike macrophages) did not exhibit phagoso-lysosomal fusion. ST-infected macrophages produced IL-6 whereas trophoblast cells produced IL-10. Neutralizing IL-10 in JEG-3 cells accelerated phagolysomal fusion and reduced proliferation of ST. Placental bacterial burden was curtailed in vivo in anti-IL-10 antibody treated and IL-10-deficient mice. DISCUSSION Macrophages phagocytose but curtail intracellular replication of ST in late phagosomes. In contrast, phagocytosis by trophoblast cells results in an inappropriate cytokine response and proliferation of ST in early phagosomes. CONCLUSION IL-10 production by trophoblast cells that delays phagosomal maturation may facilitate proliferation of pathogens in placental cells.
Collapse
Affiliation(s)
- T Nguyen
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, ON, Canada
| | | | | | | | | | | |
Collapse
|
20
|
Milev MP, Ravichandran M, Khan MF, Schriemer DC, Mouland AJ. Characterization of staufen1 ribonucleoproteins by mass spectrometry and biochemical analyses reveal the presence of diverse host proteins associated with human immunodeficiency virus type 1. Front Microbiol 2012; 3:367. [PMID: 23125841 PMCID: PMC3486646 DOI: 10.3389/fmicb.2012.00367] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 09/27/2012] [Indexed: 12/02/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) unspliced, 9 kb genomic RNA (vRNA) is exported from the nucleus for the synthesis of viral structural proteins and enzymes (Gag and Gag/Pol) and is then transported to sites of virus assembly where it is packaged into progeny virions. vRNA co-exists in the cytoplasm in the context of the HIV-1 ribonucleoprotein (RNP) that is currently defined by the presence of Gag and several host proteins including the double-stranded RNA-binding protein, Staufen1. In this study we isolated Staufen1 RNP complexes derived from HIV-1-expressing cells using tandem affinity purification and have identified multiple host protein components by mass spectrometry. Four viral proteins, including Gag, Gag/Pol, Env and Nef as well as >200 host proteins were identified in these RNPs. Moreover, HIV-1 induces both qualitative and quantitative differences in host protein content in these RNPs. 22% of Staufen1-associated factors are virion-associated suggesting that the RNP could be a vehicle to achieve this. In addition, we provide evidence on how HIV-1 modulates the composition of cytoplasmic Staufen1 RNPs. Biochemical fractionation by density gradient analyses revealed new facets on the assembly of Staufen1 RNPs. The assembly of dense Staufen1 RNPs that contain Gag and several host proteins were found to be entirely RNA-dependent but their assembly appeared to be independent of Gag expression. Gag-containing complexes fractionated into a lighter and another, more dense pool. Lastly, Staufen1 depletion studies demonstrated that the previously characterized Staufen1 HIV-1-dependent RNPs are most likely aggregates of smaller RNPs that accumulate at juxtanuclear domains. The molecular characterization of Staufen1 HIV-1 RNPs will offer important information on virus-host cell interactions and on the elucidation of the function of these RNPs for the transport of Gag and the fate of the unspliced vRNA in HIV-1-producing cells.
Collapse
Affiliation(s)
- Miroslav P Milev
- HIV-1 Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital Montréal, QC, Canada ; Division of Experimental Medicine, Department of Medicine, McGill University Montreal, QC, Canada
| | | | | | | | | |
Collapse
|
21
|
Vázquez-Calvo Á, Sobrino F, Martín-Acebes MA. Plasma membrane phosphatidylinositol 4,5 bisphosphate is required for internalization of foot-and-mouth disease virus and vesicular stomatitis virus. PLoS One 2012; 7:e45172. [PMID: 23028825 PMCID: PMC3460999 DOI: 10.1371/journal.pone.0045172] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 08/17/2012] [Indexed: 12/20/2022] Open
Abstract
Phosphatidylinositol-4,5-bisphosphate, PI(4,5)P2, is a phospholipid which plays important roles in clathrin-mediated endocytosis. To investigate the possible role of this lipid on viral entry, two viruses important for animal health were selected: the enveloped vesicular stomatitis virus (VSV) − which uses a well characterized clathrin mediated endocytic route − and two different variants of the non-enveloped foot-and-mouth disease virus (FMDV) with distinct receptor specificities. The expression of a dominant negative dynamin, a PI(4,5)P2 effector protein, inhibited the internalization and infection of VSV and both FMDV isolates. Depletion of PI(4,5)P2 from plasma membrane using ionomycin or an inducible system, and inhibition of its de novo synthesis with 1-butanol revealed that VSV as well as FMDV C-S8c1, which uses integrins as receptor, displayed a high dependence on PI(4,5)P2 for internalization. Expression of a kinase dead mutant (KD) of phosphatidylinositol-4-phosphate-5-kinase Iα (PIP5K-Iα), an enzyme responsible for PI(4,5)P2 synthesis that regulates clathrin-dependent endocytosis, also impaired entry and infection of VSV and FMDV C-S8c1. Interestingly FMDV MARLS variant that uses receptors other than integrins for cell entry was less sensitive to PI(4,5)P2 depletion, and was not inhibited by the expression of the KD PIP5K-Iα mutant suggesting the involvement of endocytic routes other than the clathrin-mediated on its entry. These results highlight the role of PI(4,5)P2 and PIP5K-Iα on clathrin-mediated viral entry.
Collapse
Affiliation(s)
- Ángela Vázquez-Calvo
- Centro de Biología Molecular “Severo Ochoa” (UAM/CSIC), Cantoblanco, Madrid Spain
| | - Francisco Sobrino
- Centro de Biología Molecular “Severo Ochoa” (UAM/CSIC), Cantoblanco, Madrid Spain
- Centro de Investigación en Sanidad Animal, INIA, Valdeolmos, Madrid, Spain
- * E-mail:
| | | |
Collapse
|
22
|
Affiliation(s)
- Varvara B Zeldovich
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, United States of America
| | | |
Collapse
|
23
|
Appelbaum JS, LaRochelle JR, Smith BA, Balkin DM, Holub JM, Schepartz A. Arginine topology controls escape of minimally cationic proteins from early endosomes to the cytoplasm. CHEMISTRY & BIOLOGY 2012; 19:819-30. [PMID: 22840770 PMCID: PMC3488872 DOI: 10.1016/j.chembiol.2012.05.022] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 05/23/2012] [Accepted: 05/25/2012] [Indexed: 12/16/2022]
Abstract
Proteins represent an expanding class of therapeutics, but their actions are limited primarily to extracellular targets because most peptidic molecules fail to enter cells. Here we identified two small proteins, miniature protein 5.3 and zinc finger module ZF5.3, that enter cells to reach the cytosol through rapid internalization and escape from Rab5+ endosomes. The trafficking pathway mapped for these molecules differs from that of Tat and Arg(8), which require transport beyond Rab5+ endosomes to gain cytosolic access. Our results suggest that the ability of 5.3 and ZF5.3 to escape from early endosomes is a unique feature and imply the existence of distinct signals, encodable within short sequences, that favor early versus late endosomal release. Identifying these signals and understanding their mechanistic basis will illustrate how cells control the movement of endocytic cargo and may allow researchers to engineer molecules to follow a desired delivery pathway for rapid cytosolic access.
Collapse
Affiliation(s)
- Jacob S. Appelbaum
- Department of Cell Biology, Yale University, 333 Cedar Street, PO Box 208002, New Haven CT 06520-8002
| | - Jonathan R. LaRochelle
- Department of Molecular, Cellular, and Developmental Biology, Yale University, PO Box 208107, New Haven CT 06520-8107
| | - Betsy A. Smith
- Department of Molecular, Cellular, and Developmental Biology, Yale University, PO Box 208107, New Haven CT 06520-8107
| | - Daniel M. Balkin
- Department of Cell Biology, Yale University, 333 Cedar Street, PO Box 208002, New Haven CT 06520-8002
| | - Justin M. Holub
- Department of Molecular, Cellular, and Developmental Biology, Yale University, PO Box 208107, New Haven CT 06520-8107
| | - Alanna Schepartz
- Department of Molecular, Cellular, and Developmental Biology, Yale University, PO Box 208107, New Haven CT 06520-8107
- Department of Chemistry, Yale University, PO Box 208107, New Haven, CT 06520-8107
| |
Collapse
|
24
|
Rosario FJ, Sadovsky Y, Jansson T. Gene targeting in primary human trophoblasts. Placenta 2012; 33:754-62. [PMID: 22831880 DOI: 10.1016/j.placenta.2012.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 07/04/2012] [Accepted: 07/05/2012] [Indexed: 12/18/2022]
Abstract
Studies in primary human trophoblasts provide critical insights into placental function in normal and complicated pregnancies. Mechanistic studies in these cells require experimental tools to modulate gene expression. Lipid-based methods to transfect primary trophoblasts are fairly simple to use and allow for the efficient delivery of nucleic acids, but potential toxic effects limit these methods. Viral vectors are versatile transfection tools of native trophoblastic or foreign cDNAs, providing high transfection efficiency, low toxicity and stable DNA integration into the trophoblast genome. RNA interference (RNAi), using small interfering RNA (siRNA) or microRNA, constitutes a powerful approach to silence trophoblast genes. However, off-target effects, such as regulation of unintended complementary transcripts, inflammatory responses and saturation of the endogenous RNAi machinery, are significant concerns. Strategies to minimize off-target effects include using multiple individual siRNAs, elimination of pro-inflammatory sequences in the siRNA construct and chemical modification of a nucleotide in the guide strand or of the ribose moiety. Tools for efficient gene targeting in primary human trophoblasts are currently available, albeit not yet extensively validated. These methods are critical for exploring the function of human trophoblast genes and may provide a foundation for the future application of gene therapy that targets placental trophoblasts.
Collapse
Affiliation(s)
- F J Rosario
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center San Antonio, Mail Code 7836, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA
| | | | | |
Collapse
|
25
|
Nachmias D, Sklan EH, Ehrlich M, Bacharach E. Human immunodeficiency virus type 1 envelope proteins traffic toward virion assembly sites via a TBC1D20/Rab1-regulated pathway. Retrovirology 2012; 9:7. [PMID: 22260459 PMCID: PMC3283470 DOI: 10.1186/1742-4690-9-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 01/19/2012] [Indexed: 01/08/2023] Open
Abstract
Background The cellular activity of many factors and pathways is required to execute the complex replication cycle of the human immunodeficiency virus type 1 (HIV-1). To reveal these cellular components, several extensive RNAi screens have been performed, listing numerous 'HIV-dependency factors'. However, only a small overlap between these lists exists, calling for further evaluation of the relevance of specific factors to HIV-1 replication and for the identification of additional cellular candidates. TBC1D20, the GTPase-activating protein (GAP) of Rab1, regulates endoplasmic reticulum (ER) to Golgi trafficking, was not identified in any of these screens, and its involvement in HIV-1 replication cycle is tested here. Findings Excessive TBC1D20 activity perturbs the early trafficking of HIV-1 envelope protein through the secretory pathway. Overexpression of TBC1D20 hampered envelope processing and reduced its association with detergent-resistant membranes, entailing a reduction in infectivity of HIV-1 virion like particles (VLPs). Conclusions These findings add TBC1D20 to the network of host factors regulating HIV replication cycle.
Collapse
Affiliation(s)
- Dikla Nachmias
- Department of Cell Research and Immunology, The George S, Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | | | | | | |
Collapse
|
26
|
Caillet M, Janvier K, Pelchen–Matthews A, Delcroix-Genête D, Camus G, Marsh M, Berlioz-Torrent C. Rab7A is required for efficient production of infectious HIV-1. PLoS Pathog 2011; 7:e1002347. [PMID: 22072966 PMCID: PMC3207927 DOI: 10.1371/journal.ppat.1002347] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 09/16/2011] [Indexed: 01/24/2023] Open
Abstract
Retroviruses take advantage of cellular trafficking machineries to assemble and release new infectious particles. Rab proteins regulate specific steps in intracellular membrane trafficking by recruiting tethering, docking and fusion factors, as well as the actin- and microtubule-based motor proteins that facilitate vesicle traffic. Using virological tests and RNA interference targeting Rab proteins, we demonstrate that the late endosome-associated Rab7A is required for HIV-1 propagation. Analysis of the late steps of the HIV infection cycle shows that Rab7A regulates Env processing, the incorporation of mature Env glycoproteins into viral particles and HIV-1 infectivity. We also show that siRNA-mediated Rab7A depletion induces a BST2/Tetherin phenotype on HIV-1 release. BST2/Tetherin is a restriction factor that impedes HIV-1 release by tethering mature virus particles to the plasma membrane. Our results suggest that Rab7A contributes to the mechanism by which Vpu counteracts the restriction factor BST2/Tetherin and rescues HIV-1 release. Altogether, our results highlight new roles for a major regulator of the late endocytic pathway, Rab7A, in the late stages of the HIV-1 replication cycle. Human immunodeficiency virus (HIV) propagation requires the assistance of host cell factors at all stages of the infection cycle. HIV exploits components of the cellular membrane sorting machinery for its assembly, budding and release. Rab GTPases are key regulators of membrane-trafficking events, including exocytosis and endocytosis, in eukaryotic cells. Here we show that the late endosome associated Rab7A plays a major role in HIV-1 replication. We find that Rab7A regulates the production of infectious HIV-1 particles at two critical stages. First, Rab7A is required for efficient Env processing and, thus, for the incorporation of mature HIV-1 envelope glycoproteins into virions. Second, Rab7A contributes to the mechanism that counteracts the restriction imposed on HIV-1 release by the cellular restriction factor BST2/Tetherin that physically tethers viral particles to the plasma membrane of infected cells. Altogether these data highlight new roles for a major player of the late endocytic pathway, Rab7A, in the late stages of the HIV-1 replication cycle.
Collapse
Affiliation(s)
- Marina Caillet
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Katy Janvier
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Annegret Pelchen–Matthews
- Cell Biology Unit, MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Delphine Delcroix-Genête
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Grégory Camus
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Mark Marsh
- Cell Biology Unit, MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Clarisse Berlioz-Torrent
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- * E-mail:
| |
Collapse
|
27
|
Flegel TW, Sritunyalucksana K. Shrimp molecular responses to viral pathogens. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2011; 13:587-607. [PMID: 20393775 DOI: 10.1007/s10126-010-9287-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 03/10/2010] [Indexed: 05/29/2023]
Abstract
From almost negligible amounts in 1970, the quantity of cultivated shrimp (~3 million metric tons in 2007) has risen to approach that of the capture fishery and it constitutes a vital source of export income for many countries. Despite this success, viral diseases along the way have caused billions of dollars of losses for shrimp farmers. Desire to reduce the losses to white spot syndrome virus in particular, has stimulated much research since 2000 on the shrimp response to viral pathogens at the molecular level. The objective of the work is to develop novel, practical methods for improved disease control. This review covers the background and limitations of the current work, baseline studies and studies on humoral responses, on binding between shrimp and viral structural proteins and on intracellular responses. It also includes discussion of several important phenomena (i.e., the quasi immune response, viral co-infections, viral sequences in the shrimp genome and persistent viral infections) for which little or no molecular information is currently available, but is much needed.
Collapse
Affiliation(s)
- T W Flegel
- National Science and Technology Development Agency (NSTDA), Klong Luang, Pathumthani 12120, Thailand.
| | | |
Collapse
|
28
|
Barroso-González J, García-Expósito L, Puigdomènech I, de Armas-Rillo L, Machado JD, Blanco J, Valenzuela-Fernández A. Viral infection: Moving through complex and dynamic cell-membrane structures. Commun Integr Biol 2011; 4:398-408. [PMID: 21966556 DOI: 10.4161/cib.4.4.16716] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 05/31/2011] [Indexed: 01/19/2023] Open
Abstract
Viruses have developed different survival strategies in host cells by crossing cell-membrane compartments, during different steps of their viral life cycle. In fact, the non-regenerative viral membrane of enveloped viruses needs to encounter the dynamic cell-host membrane, during early steps of the infection process, in which both membranes fuse, either at cell-surface or in an endocytic compartment, to promote viral entry and infection. Once inside the cell, many viruses accomplish their replication process through exploiting or modulating membrane traffic, and generating specialized compartments to assure viral replication, viral budding and spreading, which also serve to evade the immune responses against the pathogen. In this review, we have attempted to present some data that highlight the importance of membrane dynamics during viral entry and replicative processes, in order to understand how viruses use and move through different complex and dynamic cell-membrane structures and how they use them to persist.
Collapse
Affiliation(s)
- Jonathan Barroso-González
- Laboratorio de Inmunología Celular y Viral; Laboratorio de Neurosecreción; Unidad de Farmacología; Departamento de Medicina Física y Farmacología; Facultad de Medicina; Instituto de Tecnologías Biomédicas (ITB); Universidad de La Laguna (ULL)
| | - Laura García-Expósito
- Laboratorio de Inmunología Celular y Viral; Laboratorio de Neurosecreción; Unidad de Farmacología; Departamento de Medicina Física y Farmacología; Facultad de Medicina; Instituto de Tecnologías Biomédicas (ITB); Universidad de La Laguna (ULL)
| | - Isabel Puigdomènech
- Fundació irsiCaixa-HIVACAT; Institut de Recerca en Ciències de la Salut Germans Trias i Pujol (IGTP); Hospital Germans Trias i Pujol; Universitat Autònoma de Barcelona; Barcelona, Catalonia Spain
| | - Laura de Armas-Rillo
- Laboratorio de Inmunología Celular y Viral; Laboratorio de Neurosecreción; Unidad de Farmacología; Departamento de Medicina Física y Farmacología; Facultad de Medicina; Instituto de Tecnologías Biomédicas (ITB); Universidad de La Laguna (ULL)
| | - José-David Machado
- Laboratorio de Inmunología Celular y Viral; Laboratorio de Neurosecreción; Unidad de Farmacología; Departamento de Medicina Física y Farmacología; Facultad de Medicina; Instituto de Tecnologías Biomédicas (ITB); Universidad de La Laguna (ULL)
| | - Julià Blanco
- Fundació irsiCaixa-HIVACAT; Institut de Recerca en Ciències de la Salut Germans Trias i Pujol (IGTP); Hospital Germans Trias i Pujol; Universitat Autònoma de Barcelona; Barcelona, Catalonia Spain
| | - Agustín Valenzuela-Fernández
- Laboratorio de Inmunología Celular y Viral; Laboratorio de Neurosecreción; Unidad de Farmacología; Departamento de Medicina Física y Farmacología; Facultad de Medicina; Instituto de Tecnologías Biomédicas (ITB); Universidad de La Laguna (ULL)
| |
Collapse
|
29
|
|
30
|
Invasive extravillous trophoblasts restrict intracellular growth and spread of Listeria monocytogenes. PLoS Pathog 2011; 7:e1002005. [PMID: 21408203 PMCID: PMC3048367 DOI: 10.1371/journal.ppat.1002005] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 12/29/2010] [Indexed: 11/19/2022] Open
Abstract
Listeria monocytogenes is a facultative intracellular bacterial pathogen that can infect the placenta, a chimeric organ made of maternal and fetal cells. Extravillous trophoblasts (EVT) are specialized fetal cells that invade the uterine implantation site, where they come into direct contact with maternal cells. We have shown previously that EVT are the preferred site of initial placental infection. In this report, we infected primary human EVT with L. monocytogenes. EVT eliminated ∼80% of intracellular bacteria over 24-hours. Bacteria were unable to escape into the cytoplasm and remained confined to vacuolar compartments that became acidified and co-localized with LAMP1, consistent with bacterial degradation in lysosomes. In human placental organ cultures bacterial vacuolar escape rates differed between specific trophoblast subpopulations. The most invasive EVT—those that would be in direct contact with maternal cells in vivo—had lower escape rates than trophoblasts that were surrounded by fetal cells and tissues. Our results suggest that EVT present a bottleneck in the spread of L. monocytogenes from mother to fetus by inhibiting vacuolar escape, and thus intracellular bacterial growth. However, if L. monocytogenes is able to spread beyond EVT it can find a more hospitable environment. Our results elucidate a novel aspect of the maternal-fetal barrier. Infection of the placenta and fetus is an important cause of pregnancy complications and fetal and neonatal morbidity and mortality. Listeria monocytogenes is an intracellular bacterial pathogen that causes pregnancy-related infections in humans. The pathogenesis of listeriosis during pregnancy is poorly understood. We have previously shown that transmission of L. monocytogenes from maternal cells and tissues to fetal cells occurs in the uterine implantation site, and that a small subpopulation of specialized fetal cells called extravillous trophoblasts are the preferred initial site of infection. Here we use primary human placental organ and cell culture systems to characterize the intracellular fate of L. monocytogenes in extravillous trophoblasts. We found that these cells entrap bacteria in vacuolar compartments where they are degraded and therefore reduce bacterial dissemination into deeper structures of the placenta. Our study provides new insights into the nature of the maternal-fetal barrier. Extravillous trophoblasts that are accessible to infection with intracellular pathogens from infected maternal cells have host defense mechanisms that constitute a bottleneck in maternal-fetal transmission.
Collapse
|
31
|
Inhibition of Taura syndrome virus replication in Litopenaeus vannamei through silencing the LvRab7 gene using double-stranded RNA. Arch Virol 2011; 156:1117-23. [DOI: 10.1007/s00705-011-0952-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 02/10/2011] [Indexed: 12/30/2022]
|
32
|
García-Expósito L, Barroso-González J, Puigdomènech I, Machado JD, Blanco J, Valenzuela-Fernández A. HIV-1 requires Arf6-mediated membrane dynamics to efficiently enter and infect T lymphocytes. Mol Biol Cell 2011; 22:1148-66. [PMID: 21346189 PMCID: PMC3078069 DOI: 10.1091/mbc.e10-08-0722] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
As the initial barrier to viral entry, the plasma membrane along with the membrane trafficking machinery and cytoskeleton are of fundamental importance in the viral cycle. However, little is known about the contribution of plasma membrane dynamics during early human immunodeficiency virus type 1 (HIV-1) infection. Considering that ADP ribosylation factor 6 (Arf6) regulates cellular invasion via several microorganisms by coordinating membrane trafficking, our aim was to study the function of Arf6-mediated membrane dynamics on HIV-1 entry and infection of T lymphocytes. We observed that an alteration of the Arf6-guanosine 5'-diphosphate/guanosine 5'-triphosphate (GTP/GDP) cycle, by GDP-bound or GTP-bound inactive mutants or by specific Arf6 silencing, inhibited HIV-1 envelope-induced membrane fusion, entry, and infection of T lymphocytes and permissive cells, regardless of viral tropism. Furthermore, cell-to-cell HIV-1 transmission of primary human CD4(+) T lymphocytes was inhibited by Arf6 knockdown. Total internal reflection fluorescence microscopy showed that Arf6 mutants provoked the accumulation of phosphatidylinositol-(4,5)-biphosphate-associated structures on the plasma membrane of permissive cells, without affecting CD4-viral attachment but impeding CD4-dependent HIV-1 entry. Arf6 silencing or its mutants did not affect fusion, entry, and infection of vesicular stomatitis virus G-pseudotyped viruses or ligand-induced CXCR4 or CCR5 endocytosis, both clathrin-dependent processes. Therefore we propose that efficient early HIV-1 infection of CD4(+) T lymphocytes requires Arf6-coordinated plasma membrane dynamics that promote viral fusion and entry.
Collapse
|
33
|
Joo KI, Tai A, Lee CL, Wong C, Wang P. Imaging multiple intermediates of single-virus membrane fusion mediated by distinct fusion proteins. Microsc Res Tech 2010; 73:886-900. [PMID: 20232362 DOI: 10.1002/jemt.20841] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Membrane fusion plays an essential role in the entry of enveloped viruses into target cells. The merging of viral and target cell membranes is catalyzed by viral fusion proteins, which involves multiple sequential steps in the fusion process. However, the fusion mechanisms mediated by different fusion proteins involve multiple transient intermediates that have not been well characterized. Here, we report a synthetic virus platform that allows us to better understand the different fusion mechanisms driven by the diverse types fusion proteins. The platform consists of lentiviral particles coenveloped with a surface antibody, which serves as the binding protein, along with a fusion protein derived from either influenza virus (HAmu) or Sindbis virus (SINmu). By using a single virus tracking technique, we demonstrated that both HAmu- and SINmu-bearing viruses enter cells through clathrin-dependent endocytosis, but they required different endosomal trafficking routes to initiate viral fusion. Direct observation of single viral fusion events clearly showed that hemifusion mediated by SINmu upon exposure to low pH occurs faster than that mediated by HAmu. Monitoring sequential fusion processes by dual labeling the outer and inner leaflets of viral membranes also revealed that the SINmu-mediated hemifusion intermediate is relatively long-lived as compared with that mediated by HAmu. Taken together, we have demonstrated that the combination of this versatile viral platform with the techniques of single virus tracking can be a powerful tool for revealing molecular details of fusion mediated by various fusion proteins.
Collapse
Affiliation(s)
- Kye-Il Joo
- Department of Chemical Engineering and Materials Science, Viterbi School of Engineering, University of Southern California, Los Angeles, California 90089, USA
| | | | | | | | | |
Collapse
|
34
|
Ongvarrasopone C, Chomchay E, Panyim S. Antiviral effect of PmRab7 knock-down on inhibition of Laem-Singh virus replication in black tiger shrimp. Antiviral Res 2010; 88:116-8. [DOI: 10.1016/j.antiviral.2010.06.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 06/28/2010] [Accepted: 06/30/2010] [Indexed: 12/14/2022]
|
35
|
Heterogeneous pathways of maternal-fetal transmission of human viruses (review). Pathol Oncol Res 2010; 15:451-65. [PMID: 19350418 DOI: 10.1007/s12253-009-9166-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Accepted: 03/24/2009] [Indexed: 12/18/2022]
Abstract
Several viruses can pass the maternal-fetal barrier, and cause diseases of the fetus or the newborn. Recently, however, it became obvious, that viruses may invade fetal cells and organs through different routes without acute consequences. Spermatozoa, seminal fluid and lymphocytes in the sperm may transfer viruses into the human zygotes. Viruses were shown to be integrated into human chromosomes and transferred into fetal tissues. The regular maternal-fetal transport of maternal cells has also been discovered. This transport might implicate that lymphotropic viruses can be released into the fetal organs following cellular invasion. It has been shown that many viruses may replicate in human trophoblasts and syncytiotrophoblast cells thus passing the barrier of the maternal-fetal interface. The transport of viral immunocomplexes had also been suggested, and the possibility has been put forward that even anti-idiotypes mimicking viral epitopes might be transferred by natural mechanisms into the fetal plasma, in spite of the selective mechanisms of apical to basolateral transcytosis in syncytiotrophoblast and basolateral to apical transcytosis in fetal capillary endothelium. The mechanisms of maternal-fetal transcytosis seem to be different of those observed in differentiated cells and tissue cultures. Membrane fusion and lipid rafts of high cholesterol content are probably the main requirements of fetal transcytosis. The long term presence of viruses in fetal tissues and their interactions with the fetal immune system might result in post partum consequences as far as increased risk of the development of malignancies and chronic pathologic conditions are discussed.
Collapse
|
36
|
Abstract
The endocytosis pathway controls multiple cellular and physiological events. The lysosome is the destination of newly synthesized lysosomal hydrolytic enzymes. Internalized molecules or particles are delivered to the lysosome for degradation through sequential transport along the endocytic pathway. The endocytic pathway is also emerging as a signalling platform, in addition to the well-known role of the plasma membrane for signalling. Rab7 is a late endosome-/lysosome-associated small GTPase, perhaps the only lysosomal Rab protein identified to date. Rab7 plays critical roles in the endocytic processes. Through interaction with its partners (including upstream regulators and downstream effectors), Rab7 participates in multiple regulation mechanisms in endosomal sorting, biogenesis of lysosome [or LRO (lysosome-related organelle)] and phagocytosis. These processes are closely related to substrates degradation, antigen presentation, cell signalling, cell survival and microbial pathogen infection. Consistently, mutations or dysfunctions of Rab7 result in traffic disorders, which cause various diseases, such as neuropathy, cancer and lipid metabolism disease. Rab7 also plays important roles in microbial pathogen infection and survival, as well as in participating in the life cycle of viruses. Here, we give a brief review on the central role of Rab7 in endosomal traffic and summarize the studies focusing on the participation of Rab7 in disease pathogenesis. The underlying mechanism governed by Rab7 and its partners will also be discussed.
Collapse
|
37
|
Ross AL, Cannou C, Barré-Sinoussi F, Menu E. Proteasome-independent degradation of HIV-1 in naturally non-permissive human placental trophoblast cells. Retrovirology 2009; 6:46. [PMID: 19445667 PMCID: PMC2689159 DOI: 10.1186/1742-4690-6-46] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Accepted: 05/15/2009] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND The human placenta-derived cell line BeWo has been demonstrated to be restrictive to cell-free HIV-1 infection. BeWo cells are however permissive to infection by VSV-G pseudotyped HIV-1, which enters cells by a receptor-independent mechanism, and to infection by HIV-1 via a cell-to-cell route. RESULTS Here we analysed viral entry in wild type BeWo (CCR5+, CXCR4+) and BeWo-CD4+ (CD4+, CCR5+, CXCR4+) cells. We report that HIV-1 internalisation is not restricted in either cell line. Levels of internalised p24 antigen between VSV-G HIV-1 pseudotypes and R5 or X4 virions were comparable. We next analysed the fate of internalised virions; X4 and R5 HIV-1 virions were less stable over time in BeWo cells than VSV-G HIV-1 pseudotypes. We then investigated the role of the proteasome in restricting cell-free HIV-1 infection in BeWo cells using proteasome inhibitors. We observed an increase in the levels of VSV-G pseudotyped HIV-1 infection in proteasome-inhibitor treated cells, but the infection by R5-Env or X4-Env pseudotyped virions remains restricted. CONCLUSION Collectively these results suggest that cell-free HIV-1 infection encounters a surface block leading to a non-productive entry route, which either actively targets incoming virions for non-proteasomal degradation, and impedes their release into the cytoplasm, or causes the inactivation of mechanisms essential for viral replication.
Collapse
Affiliation(s)
- Anna Laura Ross
- Institut Pasteur, Unit of Regulation of Retroviral Infections, Department of Virology, 25 rue du Docteur Roux, Paris, France.
| | | | | | | |
Collapse
|
38
|
A dominant-negative mutant of rab5 inhibits infection of cells by foot-and-mouth disease virus: implications for virus entry. J Virol 2009; 83:6247-56. [PMID: 19357169 DOI: 10.1128/jvi.02460-08] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV) can use a number of different integrins (alphavbeta1, alphavbeta3, alphavbeta6, and alphavbeta8) as receptors to initiate infection. Infection mediated by alphavbeta6 is known to occur by clathrin-mediated endocytosis and is dependent on the acidic pH within endosomes. On internalization, virus is detected rapidly in early endosomes (EE) and subsequently in perinuclear recycling endosomes (PNRE), but not in late endosomal compartments. Due to the extreme sensitivity of FMDV to acidic pH, it is thought that EE can provide a pH low enough for infection to occur; however, definitive proof that infection takes place from within these compartments is still lacking. Here we have investigated the intracellular transport steps required for FMDV infection of IBRS-2 cells, which express alphavbeta8 as their FMDV receptor. These experiments confirmed that FMDV infection mediated by alphavbeta8 is also dependent on clathrin-mediate endocytosis and an acidic pH within endosomes. Also, the effect on FMDV infection of dominant-negative (DN) mutants of cellular rab proteins that regulate endosomal traffic was examined. Expression of DN rab5 reduced the number of FMDV-infected cells by 80%, while expression of DN rab4 or DN rab7 had virtually no effect on infection. Expression of DN rab11 inhibited infection by FMDV, albeit to a small extent ( approximately 35%). These results demonstrate that FMDV infection takes place predominantly from within EE and does not require virus trafficking to the late endosomal compartments. However, our results suggest that infection may not be exclusive to EE and that a small amount of infection could occur from within PNRE.
Collapse
|
39
|
Wu JQ, Dwyer DE, Dyer WB, Yang YH, Wang B, Saksena NK. Transcriptional profiles in CD8+ T cells from HIV+ progressors on HAART are characterized by coordinated up-regulation of oxidative phosphorylation enzymes and interferon responses. Virology 2008; 380:124-35. [PMID: 18692859 DOI: 10.1016/j.virol.2008.06.039] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 06/09/2008] [Accepted: 06/25/2008] [Indexed: 02/06/2023]
Abstract
The functional impairment and numerical decline of CD8+ T cells during HIV infection has a profound effect on disease progression, but only limited microarray studies have used CD8+ T cells. To understand the interactions of HIV and host CD8+ T cells at different disease status, we used the Illumina Human-6 BeadChips to evaluate the transcriptional profile (>48,000 transcripts) in primary CD8+ T cells from HIV+ therapy-naive non-progressors and therapy-experienced progressors. 68 differentially expressed genes were identified, of which 6 have been reported in HIV context, while others are associated with biological functions relevant to HIV pathogenesis. By GSEA, the coordinated up-regulation of oxidative phosphorylation enzymes and interferon responses were detected as fingerprints in HIV progressors on HAART, whereas LTNP displayed a transcriptional signature of coordinated up-regulation of components of MAPK and cytotoxicty pathways. These results will provide biological insights into natural control of HIV versus HIV control under HAART.
Collapse
Affiliation(s)
- Jing Qin Wu
- Retroviral Genetics Division, Center for Virus Research, Westmead Millennium Institute, University of Sydney, Westmead, NSW, Australia.
| | | | | | | | | | | |
Collapse
|
40
|
Ongvarrasopone C, Chanasakulniyom M, Sritunyalucksana K, Panyim S. Suppression of PmRab7 by dsRNA inhibits WSSV or YHV infection in shrimp. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2008; 10:374-381. [PMID: 18214608 DOI: 10.1007/s10126-007-9073-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Revised: 11/12/2007] [Accepted: 11/26/2007] [Indexed: 05/25/2023]
Abstract
Viral entry into host cells requires endocytosis machineries of the host for viral replication. PmRab7, a Penaeus monodon small GTPase protein, was investigated for its function in vesicular transport during viral infection. The double-stranded RNA of Rab7 was injected into a juvenile shrimp before challenging with white spot syndrome virus (WSSV) or yellow head virus (YHV). PmRab7 mRNA was specifically decreased at 48 h after dsRNA-Rab7 injection. Silencing of PmRab7 dramatically inhibited WSSV-VP28 mRNA and protein expression. Unexpectedly, the silencing of PmRab7 also inhibited YHV replication in the YHV-infected shrimp. These results suggested that PmRab7 is a common cellular factor required for WSSV or YHV replication in shrimp. Because PmRab7 should function in the endosomal trafficking pathway, its silencing prevents successful viral trafficking necessary for replication. Silencing of PmRab7 could be a novel approach to prevent both DNA virus (WSSV) and RNA virus (YHV) infection of shrimp.
Collapse
Affiliation(s)
- Chalermporn Ongvarrasopone
- Institute of Molecular Biology and Genetics, Mahidol University, Salaya Campus, Nakhon Pathom, Thailand.
| | | | | | | |
Collapse
|
41
|
Mercier S, St-Pierre C, Pelletier I, Ouellet M, Tremblay MJ, Sato S. Galectin-1 promotes HIV-1 infectivity in macrophages through stabilization of viral adsorption. Virology 2007; 371:121-9. [PMID: 18028978 DOI: 10.1016/j.virol.2007.09.034] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 07/23/2007] [Accepted: 09/22/2007] [Indexed: 11/17/2022]
Abstract
Following primary infection with human immunodeficiency virus type-1 (HIV-1), macrophages are thought to play an important role, as they are one of the first target cells the virus encounters and can also sustain a significant production of viruses over extended periods of time. While the interaction between the primary cellular receptor CD4 and the virus-encoded external envelope glycoprotein gp120 initiates the infection process, it has been suggested that various host factors are exploited by HIV-1 to facilitate adsorption onto the cell surface. Macrophages and other cells found at the infection site can secrete a soluble mammalian lectin, galectin-1, which binds to beta-galactoside residues through its carbohydrate recognition domain. Being a dimer, galectin-1 can cross-link ligands expressed on different constituents to mediate adhesion between cells or between cells and pathogens. We report here that galectin-1, but not galectin-3, increased HIV-1 infectivity in monocyte-derived macrophages (MDMs). This phenomenon was likely due to an enhancement of virus adsorption kinetics, which facilitates HIV-1 entry. The fusion inhibitors T-20 and TAK779 remained effective at reducing infection even in the presence of galectin-1, indicating that the galectin-1-mediated effect is occurring at a step prior to fusion. Together, our data suggest that galectin-1 can facilitate HIV-1 infection in MDMs by promoting early events of the virus replicative cycle (i.e. adsorption).
Collapse
Affiliation(s)
- Simon Mercier
- Research Center for Infectious Diseases, CHUL Research Center, Quebec, Canada
| | | | | | | | | | | |
Collapse
|
42
|
Sklan EH, Staschke K, Oakes TM, Elazar M, Winters M, Aroeti B, Danieli T, Glenn JS. A Rab-GAP TBC domain protein binds hepatitis C virus NS5A and mediates viral replication. J Virol 2007; 81:11096-105. [PMID: 17686842 PMCID: PMC2045567 DOI: 10.1128/jvi.01249-07] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hepatitis C virus (HCV) is an important cause of liver disease worldwide. Current therapies are inadequate for most patients. Using a two-hybrid screen, we isolated a novel cellular binding partner interacting with the N terminus of HCV nonstructural protein NS5A. This partner contains a TBC Rab-GAP (GTPase-activating protein) homology domain found in all known Rab-activating proteins. As the first described interaction between such a Rab-GAP and a viral protein, this finding suggests a new mechanism whereby viruses may subvert host cell machinery for mediating the endocytosis, trafficking, and sorting of their own proteins. Moreover, depleting the expression of this partner severely impairs HCV RNA replication with no obvious effect on cell viability. These results suggest that pharmacologic disruption of this NS5A-interacting partner can be contemplated as a potential new antiviral strategy against a pathogen affecting nearly 3% of the world's population.
Collapse
Affiliation(s)
- Ella H Sklan
- Division of Gastroenterology and Hepatology, Stanford University School of Medicine, CCSR 3115A, 269 Campus Drive, Palo Alto, CA 94305-5187, USA
| | | | | | | | | | | | | | | |
Collapse
|
43
|
Bhat P, Anderson DA. Hepatitis B virus translocates across a trophoblastic barrier. J Virol 2007; 81:7200-7. [PMID: 17442714 PMCID: PMC1933314 DOI: 10.1128/jvi.02371-06] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Accepted: 04/08/2007] [Indexed: 12/20/2022] Open
Abstract
Mother-infant transmission of hepatitis B virus (HBV) accounts for up to 30% of worldwide chronic infections. The mechanism and high-risk period of HBV transmission from mother to infant are unknown. Although largely prevented by neonatal vaccination, significant transmission continues to occur in high-risk populations. It is unclear whether HBV can traverse an intact epithelial barrier to infect a new host. Transplacental transmission of a number of viruses relies on transcytotic pathways across placental cells. We wished to determine whether infectious HBV can traverse a polarized trophoblast monolayer. We used a human placenta-derived cell line, BeWo, cultured on membranes as polarized monolayers, to model the maternal-fetal barrier. We assessed the effects of placental maturity and maternal immunoglobulin on viral transport. Intracellular viral trafficking pathways were investigated by confocal microscopy. Free HBV (and infectious duck hepatitis B virus) transcytosed across trophoblastic cells at a rate of 5% in 30 min. Viral transport occurred in microtubule-dependent endosomal vesicles. Additionally, confocal microscopy showed that the internalized virus traverses a monensin-sensitive endosomal compartment. Differentiation of the cytotrophoblasts to syncytiotrophoblasts resulted in a 25% reduction in viral transcytosis, suggesting that placental maturity may protect the fetus. Virus translocation was also reduced in the presence of HBV immunoglobulin. We show for the first time that transcytosis of infectious hepadnavirus can occur across a trophoblastic barrier early in gestation, with the risk of transmission being reduced by placental maturity and specific maternal antibody. This study suggests a mechanism by which mother-infant transmission may occur.
Collapse
Affiliation(s)
- Purnima Bhat
- School of Biomedical Sciences, The University of Queensland, St. Lucia 4072, Australia.
| | | |
Collapse
|
44
|
Vidricaire G, Tremblay MJ. A Clathrin, Caveolae, and Dynamin-independent Endocytic Pathway Requiring Free Membrane Cholesterol Drives HIV-1 Internalization and Infection in Polarized Trophoblastic Cells. J Mol Biol 2007; 368:1267-83. [PMID: 17395200 DOI: 10.1016/j.jmb.2007.03.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Revised: 03/02/2007] [Accepted: 03/02/2007] [Indexed: 02/06/2023]
Abstract
In human trophoblastic cells, a correlation between early endosomal trafficking of HIV-1 and virus infection was previously documented. However, if HIV-1 is massively internalized in these cells, the endocytic pathway(s) responsible for viral uptake is still undefined. Here we address this vital question. Amongst all the putative endocytic pathways present in polarized trophoblastic cells, we demonstrate that HIV-1 infection of these cells is independent of clathrin-mediated endocytosis and macropinocytosis. Importantly, treatment with the cholesterol-sequestering drug filipin severely impairs virus internalization, whereas the cholesterol-depleting compound methyl-beta-cyclodextrin has no impact on this pathway. Moreover, viral internalization is unaffected by overexpression of a mutant dynamin 2 or treatment with a kinase or tyrosine phosphatase inhibitor. Thus, HIV-1 infection in polarized trophoblastic cells occurs primarily via a clathrin, caveolae, and dynamin-independent pathway requiring free cholesterol. Notably, even though HIV-1 did not initially co-localize with transferrin, some virions migrate at later time points to transferrin-enriched endosomes, suggesting an unusual transit from the non-classical pathway to early endosomes. Finally, virus internalization in these cells does not involve the participation of microtubules but relies partly on actin filaments. Collectively these findings provide unprecedented information on the route of HIV-1 internalization in polarized human trophoblasts.
Collapse
Affiliation(s)
- Gaël Vidricaire
- Research Center in Infectious Diseases, CHUL Research Center, and Department of Medical Biology, Faculty of Medicine, Laval University, Quebec, Canada G1V 4G2
| | | |
Collapse
|
45
|
Abstract
Retroviruses make a long and complex journey from outside the cell to the nucleus in the early stages of infection, and then an equally long journey back out again in the late stages of infection. Ongoing efforts are identifying an enormous array of cellular proteins that are used by the viruses in the course of their travels. These host factors are potential new targets for therapeutic intervention.
Collapse
Affiliation(s)
- Stephen P Goff
- Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute HHSC 1310c, College of Physicians and Surgeons, Columbia University, 701 West 168th Street, New York, New York 10032, USA.
| |
Collapse
|
46
|
Deinhardt K, Salinas S, Verastegui C, Watson R, Worth D, Hanrahan S, Bucci C, Schiavo G. Rab5 and Rab7 control endocytic sorting along the axonal retrograde transport pathway. Neuron 2007; 52:293-305. [PMID: 17046692 DOI: 10.1016/j.neuron.2006.08.018] [Citation(s) in RCA: 364] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Revised: 06/26/2006] [Accepted: 08/07/2006] [Indexed: 12/16/2022]
Abstract
Vesicular pathways coupling the neuromuscular junction with the motor neuron soma are essential for neuronal function and survival. To characterize the organelles responsible for this long-distance crosstalk, we developed a purification strategy based on a fragment of tetanus neurotoxin (TeNT H(C)) conjugated to paramagnetic beads. This approach enabled us to identify, among other factors, the small GTPase Rab7 as a functional marker of a specific pool of axonal retrograde carriers, which transport neurotrophins and their receptors. Furthermore, Rab5 is essential for an early step in TeNT H(C) sorting but is absent from axonally transported vesicles. Our data demonstrate that TeNT H(C) uses a retrograde transport pathway shared with p75(NTR), TrkB, and BDNF, which is strictly dependent on the activities of both Rab5 and Rab7. Therefore, Rab7 plays an essential role in axonal retrograde transport by controlling a vesicular compartment implicated in neurotrophin traffic.
Collapse
Affiliation(s)
- Katrin Deinhardt
- Molecular NeuroPathobiology Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3PX, United Kingdom
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Abstract
Productive viral infection is dependent upon post-entry migration of viruses/viral components to sites within a host cell that complement viral deficiencies. Delivery of virions or component proteins to appropriate sites within an infected cell is critical for completing successive stages in viral replication, including release into the cytoplasm, uncoating, genome replication, viral gene expression, assembly and budding. Vesicular transport is essential for steady-state cellular trafficking of membrane-associated proteins. Rab GTPases and their associated effectors are key regulators of vesicular transport pathways. In recent years, Rab proteins have been implicated in the endocytic or exocytic sorting of component viral proteins or intact viruses, most of which are known to be membrane-encapsulated and enveloped. This review will discuss the current understanding of how Rab GTPases and their effectors may regulate individual vesicular transport steps, and detail emerging discoveries examining how specific Rabs and effectors support viral replication.
Collapse
Affiliation(s)
- Thomas W Hodge
- University of Georgia, College of Veterinary Medicine, Department of Infectious Diseases, Athens, GA 30602, USA, and, Hudson–Alpha Institute for Biotechnology Investigator, Huntsville, AL, USA
| | - James L Murray
- University of Georgia, Animal Health Research Center, 111 Carlton Street, Room 113, Athens, GA 30602, USA
| |
Collapse
|
48
|
Kfutwah AKW, Mary JY, Nicola MA, Blaise-Boisseau S, Barré-Sinoussi F, Ayouba A, Menu E. Tumour necrosis factor-alpha stimulates HIV-1 replication in single-cycle infection of human term placental villi fragments in a time, viral dose and envelope dependent manner. Retrovirology 2006; 3:36. [PMID: 16796744 PMCID: PMC1533858 DOI: 10.1186/1742-4690-3-36] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2006] [Accepted: 06/23/2006] [Indexed: 11/23/2022] Open
Abstract
Background The placenta plays an important role in the control of in utero HIV-1 mother-to-child transmission (MTCT). Proinflammatory cytokines in the placental environment are particularly implicated in this control. We thus investigated the effect of TNF-α on HIV-1 expression in human placental tissues in vitro. Results Human placental chorionic villi fragments were infected with varying doses of luciferase reporter HIV-1 pseudotypes with the R5, X4-Env or the vesicular stomatitis virus protein G (VSV-G). Histocultures were then performed in the presence or absence of recombinant human TNF-α. Luciferase activity was measured at different time points in cell lysates or on whole fragments using ex vivo imaging systems. A significant increase in viral expression was detected in placental fragments infected with 0.2 ng of p24 antigen/fragment (P = 0.002) of VSV-G pseudotyped HIV-1 in the presence of TNF-α seen after 120 hours of culture. A time independent significant increase of viral expression by TNF-α was observed with higher doses of VSV-G pseudotyped HIV-1. When placental fragments were infected with R5-Env pseudotyped HIV-1, a low level of HIV expression at 168 hours of culture was detected for 3 of the 5 placentas tested, with no statistically significant enhancement by TNF-α. Infection with X4-Env pseudotyped HIV-1 did not lead to any detectable luciferase activity at any time point in the absence or in the presence of TNF-α. Conclusion TNF-α in the placental environment increases HIV-1 expression and could facilitate MTCT of HIV-1, particularly in an inflammatory context.
Collapse
Affiliation(s)
| | - Jean-Yves Mary
- INSERM U717, Université Paris 7, Hôpital St Louis, Paris, France
| | | | | | | | - Ahidjo Ayouba
- Unité Régulation des Infections Rétrovirales, Institut Pasteur, Paris, France
| | - Elisabeth Menu
- Unité Régulation des Infections Rétrovirales, Institut Pasteur, Paris, France
| |
Collapse
|
49
|
Gruenberg J, van der Goot FG. Mechanisms of pathogen entry through the endosomal compartments. Nat Rev Mol Cell Biol 2006; 7:495-504. [PMID: 16773132 DOI: 10.1038/nrm1959] [Citation(s) in RCA: 274] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Several pathogens - bacteria, viruses and parasites - must enter mammalian cells for survival, replication and immune-system evasion. These pathogens generally make use of existing cellular pathways that are designed for nutrient uptake, receptor downregulation and signalling. Because most of these pathways end in lysosomes, an organelle that is capable of killing microorganisms, pathogens have developed remarkable means to avoid interactions with this lytic organelle.
Collapse
Affiliation(s)
- Jean Gruenberg
- Department of Biochemistry, University of Geneva, 30 quai Ernest Ansermet, 1211 Geneva, Switzerland.
| | | |
Collapse
|
50
|
Spooner RA, Smith DC, Easton AJ, Roberts LM, Lord JM. Retrograde transport pathways utilised by viruses and protein toxins. Virol J 2006; 3:26. [PMID: 16603059 PMCID: PMC1524934 DOI: 10.1186/1743-422x-3-26] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Accepted: 04/07/2006] [Indexed: 11/15/2022] Open
Abstract
A model has been presented for retrograde transport of certain toxins and viruses from the cell surface to the ER that suggests an obligatory interaction with a glycolipid receptor at the cell surface. Here we review studies on the ER trafficking cholera toxin, Shiga and Shiga-like toxins, Pseudomonas exotoxin A and ricin, and compare the retrograde routes followed by these protein toxins to those of the ER trafficking SV40 and polyoma viruses. We conclude that there is in fact no obligatory requirement for a glycolipid receptor, nor even with a protein receptor in a lipid-rich environment. Emerging data suggests instead that there is no common pathway utilised for retrograde transport by all of these pathogens, the choice of route being determined by the particular receptor utilised.
Collapse
Affiliation(s)
- Robert A Spooner
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Daniel C Smith
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Andrew J Easton
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Lynne M Roberts
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - J Michael Lord
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK
| |
Collapse
|