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Wang X, Tang S, Song X, Rong L. Mathematical analysis of an HIV latent infection model including both virus-to-cell infection and cell-to-cell transmission. JOURNAL OF BIOLOGICAL DYNAMICS 2017; 11:455-483. [PMID: 27730851 DOI: 10.1080/17513758.2016.1242784] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
HIV can infect cells via virus-to-cell infection or cell-to-cell viral transmission. These two infection modes may occur in a synergistic way and facilitate viral spread within an infected individual. In this paper, we developed an HIV latent infection model including both modes of transmission and time delays between viral entry and integration or viral production. We analysed the model by defining the basic reproductive number, showing the existence, positivity and boundedness of the solution, and proving the local and global stability of the infection-free and infected steady states. Numerical simulations have been performed to illustrate the theoretical results and evaluate the effects of time delays and fractions of infection leading to latency on the virus dynamics. The estimates of the relative contributions to the HIV latent reservoir and the virus population from the two modes of transmission have also been provided.
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Affiliation(s)
- Xia Wang
- a College of Mathematics and Information Science , Xinyang Normal University , Xinyang , People's Republic of China
| | - Sanyi Tang
- b College of Mathematics and Information Science , Shaanxi Normal University , Xi'an , People's Republic of China
| | - Xinyu Song
- a College of Mathematics and Information Science , Xinyang Normal University , Xinyang , People's Republic of China
| | - Libin Rong
- c Department of Mathematics and Statistics , Oakland University , Rochester , MI , USA
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102
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Sakin V, Hanne J, Dunder J, Anders-Össwein M, Laketa V, Nikić I, Kräusslich HG, Lemke EA, Müller B. A Versatile Tool for Live-Cell Imaging and Super-Resolution Nanoscopy Studies of HIV-1 Env Distribution and Mobility. Cell Chem Biol 2017; 24:635-645.e5. [PMID: 28457706 DOI: 10.1016/j.chembiol.2017.04.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/12/2017] [Accepted: 04/06/2017] [Indexed: 12/27/2022]
Abstract
The envelope glycoproteins (Env) of HIV-1 mediate cell entry through fusion of the viral envelope with a target cell membrane. Intramembrane mobility and clustering of Env trimers at the viral budding site are essential for its function. Previous live-cell and super-resolution microscopy studies were limited by lack of a functional fluorescent Env derivative, requiring antibody labeling for detection. Introduction of a bio-orthogonal amino acid by genetic code expansion, combined with click chemistry, offers novel possibilities for site-specific, minimally invasive labeling. Using this approach, we established efficient incorporation of non-canonical amino acids within HIV-1 Env in mammalian cells. The engineered protein retained plasma membrane localization, glycosylation, virion incorporation, and fusogenic activity, and could be rapidly and specifically labeled with synthetic dyes. This strategy allowed us to revisit Env dynamics and nanoscale distribution at the plasma membrane close to its native state, applying fluorescence recovery after photo bleaching and STED nanoscopy, respectively.
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Affiliation(s)
- Volkan Sakin
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Janina Hanne
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; Optical Nanoscopy Division, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Jessica Dunder
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Maria Anders-Össwein
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Vibor Laketa
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; German Center for Infection Research, Partner Site Heidelberg, 69120 Heidelberg, Germany
| | - Ivana Nikić
- Structural and Computational Biology Unit, Cell Biology and Biophysics Unit, EMBL, 69117 Heidelberg, Germany
| | - Hans-Georg Kräusslich
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; German Center for Infection Research, Partner Site Heidelberg, 69120 Heidelberg, Germany
| | - Edward A Lemke
- Structural and Computational Biology Unit, Cell Biology and Biophysics Unit, EMBL, 69117 Heidelberg, Germany
| | - Barbara Müller
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
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103
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JAK-STAT Signaling Pathways and Inhibitors Affect Reversion of Envelope-Mutated HIV-1. J Virol 2017; 91:JVI.00075-17. [PMID: 28202754 DOI: 10.1128/jvi.00075-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 02/08/2017] [Indexed: 11/20/2022] Open
Abstract
HIV can spread by both cell-free and cell-to-cell transmission. Here, we show that many of the amino acid changes in Env that are close to the CD4 binding pocket can affect HIV replication. We generated a number of mutant viruses that were unable to infect T cells as cell-free viruses but were nevertheless able to infect certain T cell lines as cell-associated viruses, which was followed by reversion to the wild type. However, the activation of JAK-STAT signaling pathways caused the inhibition of such cell-to-cell infection as well as the reversion of multiple HIV Env mutants that displayed differences in their abilities to bind to the CD4 receptor. Specifically, two T cell activators, interleukin-2 (IL-2) and phorbol 12-myristate 13-acetate (PMA), both capable of activation of JAK-STAT pathways, were able to inhibit cell-to-cell viral transmission. In contrast, but consistent with the above result, a number of JAK-STAT and mTOR inhibitors actually promoted HIV-1 transmission and reversion. Hence, JAK-STAT signaling pathways may differentially affect the replication of a variety of HIV Env mutants in ways that differ from the role that these pathways play in the replication of wild-type viruses.IMPORTANCE Specific alterations in HIV Env close to the CD4 binding site can differentially change the ability of HIV to mediate infection for cell-free and cell-associated viruses. However, such differences are dependent to some extent on the types of target cells used. JAK-STAT signaling pathways are able to play major roles in these processes. This work sheds new light on factors that can govern HIV infection of target cells.
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104
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Collective Infectious Units in Viruses. Trends Microbiol 2017; 25:402-412. [PMID: 28262512 DOI: 10.1016/j.tim.2017.02.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/13/2016] [Accepted: 02/06/2017] [Indexed: 01/15/2023]
Abstract
Increasing evidence indicates that viruses do not simply propagate as independent virions among cells, organs, and hosts. Instead, viral spread is often mediated by structures that simultaneously transport groups of viral genomes, such as polyploid virions, aggregates of virions, virion-containing proteinaceous structures, secreted lipid vesicles, and virus-induced cell-cell contacts. These structures increase the multiplicity of infection, independently of viral population density and transmission bottlenecks. Collective infectious units may contribute to the maintenance of viral genetic diversity, and could have implications for the evolution of social-like virus-virus interactions. These may include various forms of cooperation such as immunity evasion, genetic complementation, division of labor, and relaxation of fitness trade-offs, but also noncooperative interactions such as negative dominance and interference, potentially leading to conflict.
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105
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Prasad A, Kulkarni R, Jiang S, Groopman JE. Cocaine Enhances DC to T-cell HIV-1 Transmission by Activating DC-SIGN/LARG/LSP1 Complex and Facilitating Infectious Synapse Formation. Sci Rep 2017; 7:40648. [PMID: 28094782 PMCID: PMC5240552 DOI: 10.1038/srep40648] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 12/09/2016] [Indexed: 02/06/2023] Open
Abstract
DC-SIGN is a dendritic cell surface structure which participates in binding and transmission of HIV-1. Here, for the first time we demonstrate that cocaine induces over expression of DC-SIGN and significantly enhances virus transfer from DCs to T-cells by increasing the binding and internalization of HIV-1 in DCs. We found that cocaine activates a DC-SIGN mediated 'signalosome' complex by enhancing its association with LARG and LSP1. Further, LARG was observed to participate in DC-SIGN mediated internalization of HIV-1 in DCs. Intracellular trafficking studies of HIV-1 in cocaine treated DCs revealed increased co-localization of HIV-1 with endosomal or multi vesicular body (MVB) markers such as CD81 and VPS4 and decreased co-localization with the phagolysomal marker LAMP1; this signified altered intracellular trafficking and decreased degradation of HIV-1 in cocaine treated DCs. Furthermore, we found that cocaine induced activation of LARG which in turn activated Rho A and the focal adhesion molecules FAK, Pyk2 and paxillin. This signaling cascade enhanced the formation of an infectious synapse between DCs and T-cells. Our study provides insight into the molecular mechanisms of cocaine's contribution to key components in HIV pathogenesis and highlights novel targets for interrupting the virus life cycle in substance using hosts.
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Affiliation(s)
- Anil Prasad
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Rutuja Kulkarni
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Shuxian Jiang
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Jerome E. Groopman
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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106
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Role of Drebrin at the Immunological Synapse. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1006:271-280. [PMID: 28865025 DOI: 10.1007/978-4-431-56550-5_15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Although drebrin was first described in neurons, it is also expressed in cells of the immune system, such as T lymphocytes and mast cells. Another member of the drebrin family of proteins, mammalian actin-binding protein 1 (mAbp-1) is more widely expressed and plays important roles in the function of macrophages, polymorphonuclear neutrophils, and B lymphocytes. We will briefly discuss on the function of mAbp-1 and drebrin in immune cells with emphasis on T cells. Specifically, drebrin enables the immune responses of CD4+ T lymphocytes. T cells are activated after the recognition of an antigen presented by antigen-presenting cells through cognate cell-cell contacts called immunological synapses (IS). In CD4+ T cells, drebrin associates with the chemokine receptor CXCR4, and both molecules redistribute to the IS displaying similar dynamics. Through its interaction with CXCR4 and the actin cytoskeleton, drebrin regulates T cell activation. CD4+ T cells are one of the main targets for the human immunodeficiency virus (HIV)-1. This virus utilizes the IS structure to be transmitted to uninfected cells, forming cell-cell contacts called virological synapses (VS). Interestingly, drebrin negatively regulates HIV-1 infection of CD4+ T lymphocytes, by regulating actin polymerization at the VS.
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107
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Martinez MG, Kielian M. Intercellular Extensions Are Induced by the Alphavirus Structural Proteins and Mediate Virus Transmission. PLoS Pathog 2016; 12:e1006061. [PMID: 27977778 PMCID: PMC5158078 DOI: 10.1371/journal.ppat.1006061] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/13/2016] [Indexed: 11/19/2022] Open
Abstract
Alphaviruses are highly organized enveloped RNA viruses with an internal nucleocapsid surrounded by a membrane containing the E2 and E1 transmembrane proteins. Alphavirus budding takes place at the plasma membrane and requires the interaction of the cytoplasmic domain of E2 with the capsid protein. Here we used WT alphaviruses and Sindbis virus in which E2 was fused to a fluorescent protein to characterize virus exit from host cells. Our results show that alphavirus infection induced striking modifications of the host cell cytoskeleton and resulted in the formation of stable intercellular extensions that emanated exclusively from the infected cell. The intercellular extensions were long (> 10 μM), contained actin and tubulin, and formed flattened contacts with neighboring cells, but did not mediate membrane or cytoplasmic continuity between cells. Receptor down-regulation studies indicated that formation of stable extensions did not require the virus receptor, and that extensions promoted cell-to-cell virus transmission to receptor-depleted cells. Virus mutant experiments demonstrated that formation of extensions required the E2-capsid interaction but not active particle budding, while intercellular transmission of infection required the production of fusion-active virus particles. Protein expression studies showed that even in the absence of virus infection, the viral structural proteins alone induced intercellular extensions, and that these extensions were preferentially targeted to non-expressing cells. Together, our results identify a mechanism for alphavirus cell-to-cell transmission and define the key viral protein interactions that it requires. Alphaviruses are a group of small enveloped RNA viruses that include a number of important human pathogens such as Chikungunya virus and viruses that cause fatal encephalitis. Chikungunya virus emerged recently in a number of countries worldwide including the Americas, where it has caused major outbreaks. Vaccines and anti-viral strategies for these viruses are urgently needed, and basic information on the alphavirus infection pathway will help in targeting critical steps. Here we describe the changes in the alphavirus-infected cell that allow it to transmit virus to neighboring uninfected cells. Infected cells form long extensions that contact neighboring cells and mediate cell-to-cell virus transmission. This mechanism of virus transmission may help to shield virus from neutralization by host antibodies. Surprisingly, expression of the viral structural proteins alone induces these intercellular extensions, which preferentially target non-expressing cells. We used this system to define a critical interaction of the capsid and envelope protein that is required for formation of extensions.
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Affiliation(s)
- Maria Guadalupe Martinez
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Margaret Kielian
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail:
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108
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Nanbo A, Kachi K, Yoshiyama H, Ohba Y. Epstein–Barr virus exploits host endocytic machinery for cell-to-cell viral transmission rather than a virological synapse. J Gen Virol 2016; 97:2989-3006. [DOI: 10.1099/jgv.0.000605] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Asuka Nanbo
- Department of Cell Physiology, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo, Japan
| | - Kunihiro Kachi
- Graduate School of Pharmaceutical Sciences, Hokkaido University, N12 W6, Kita-ku, Sapporo, Japan
| | - Hironori Yoshiyama
- Department of Microbiology, Shimane University Faculty of Medicine, 89-1, Enya-cho, Izumo, Shimane, Japan
| | - Yusuke Ohba
- Department of Cell Physiology, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo, Japan
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109
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Miller KD, Schnell MJ, Rall GF. Keeping it in check: chronic viral infection and antiviral immunity in the brain. Nat Rev Neurosci 2016; 17:766-776. [PMID: 27811921 DOI: 10.1038/nrn.2016.140] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
It is becoming clear that the manner by which the immune response resolves or contains infection by a pathogen varies according to the tissue that is affected. Unlike many peripheral cell types, CNS neurons are generally non-renewable. Thus, the cytolytic and inflammatory strategies that are effective in controlling infections in the periphery could be damaging if deployed in the CNS. Perhaps for this reason, the immune response to some CNS viral infections favours maintenance of neuronal integrity and non-neurolytic viral control. This modified immune response - when combined with the unique anatomy and physiology of the CNS - provides an ideal environment for the maintenance of viral genomes, including those of RNA viruses. Therefore, it is possible that such viruses can reactivate long after initial viral exposure, contributing to CNS disease.
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Affiliation(s)
- Katelyn D Miller
- Program in Cell and Molecular Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.,Program in Blood Cell Development and Function, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA
| | - Matthias J Schnell
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | - Glenn F Rall
- Program in Blood Cell Development and Function, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA
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110
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Characterization of a recombinant Newcastle disease virus expressing the glycoprotein of bovine ephemeral fever virus. Arch Virol 2016; 162:359-367. [PMID: 27757685 PMCID: PMC5306239 DOI: 10.1007/s00705-016-3078-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 09/19/2016] [Indexed: 11/13/2022]
Abstract
Bovine ephemeral fever (BEF) is caused by the arthropod-borne bovine ephemeral fever virus (BEFV), which is a member of the family Rhabdoviridae and the genus Ephemerovirus. BEFV causes an acute febrile infection in cattle and water buffalo. In this study, a recombinant Newcastle disease virus (NDV) expressing the glycoprotein (G) of BEFV (rL-BEFV-G) was constructed, and its biological characteristics in vitro and in vivo, pathogenicity, and immune response in mice and cattle were evaluated. BEFV G enabled NDV to spread from cell to cell. rL-BEFV-G remained nonvirulent in poultry and mice compared with vector LaSota virus. rL-BEFV-G triggered a high titer of neutralizing antibodies against BEFV in mice and cattle. These results suggest that rL-BEFV-G might be a suitable candidate vaccine against BEF.
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111
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Modelling the Impact of Cell-To-Cell Transmission in Hepatitis B Virus. PLoS One 2016; 11:e0161978. [PMID: 27560827 PMCID: PMC4999077 DOI: 10.1371/journal.pone.0161978] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/15/2016] [Indexed: 12/11/2022] Open
Abstract
Cell-free virus is a well-recognized and efficient mechanism for the spread of hepatitis B virus (HBV) infection in the liver. Cell-to-cell transmission (CCT) can be a more efficient means of virus propagation. Despite experimental evidence implying CCT occurs in HBV, its relative impact is uncertain. We develop a 3-D agent-based model where each hepatocyte changes its viral state according to a dynamical process driven by cell-free virus infection, CCT and intracellular replication. We determine the relative importance of CCT in the development and resolution of acute HBV infection in the presence of cytolytic (CTL) and non-CTL mechanisms. T cell clearance number is defined as the minimum number of infected cells needed to be killed by each T cell at peak infection that results in infection clearance within 12 weeks with hepatocyte turnover (HT, number of equivalent livers) ≤3. We find that CCT has very little impact on the establishment of infection as the mean cccDNA copies/cell remains between 15 to 20 at the peak of the infection regardless of CCT strength. In contrast, CCT inhibit immune-mediated clearance of acute HBV infection as higher CCT strength requires higher T cell clearance number and increases the probability of T cell exhaustion. An effective non-CTL inhibition can counter these negative effects of higher strengths of CCT by supporting rapid, efficient viral clearance and with little liver destruction. This is evident as the T cell clearance number drops by approximately 50% when non-CTL inhibition is increased from 10% to 80%. Higher CCT strength also increases the probability of the incidence of fulminant hepatitis with this phenomenon being unlikely to arise for no CCT. In conclusion, we report the possibility of CCT impacting HBV clearance and its contribution to fulminant hepatitis.
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112
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Cell-Free versus Cell-to-Cell Infection by Human Immunodeficiency Virus Type 1 and Human T-Lymphotropic Virus Type 1: Exploring the Link among Viral Source, Viral Trafficking, and Viral Replication. J Virol 2016; 90:7607-17. [PMID: 27334587 DOI: 10.1128/jvi.00407-16] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) and human T-lymphotropic virus type 1 (HTLV-1) are complex retroviruses mainly infecting CD4(+) T lymphocytes. In addition, antigen-presenting cells such as dendritic cells (DCs) are targeted in vivo by both viruses, although to a lesser extent. Interaction of HIV-1 with DCs plays a key role in viral dissemination from the mucosa to CD4(+) T lymphocytes present in lymphoid organs. While similar mechanisms may occur for HTLV-1 as well, most HTLV-1 data were obtained from T-cell studies, and little is known regarding the trafficking of this virus in DCs. We first compared the efficiency of cell-free versus cell-associated viral sources of both retroviruses at infecting DCs. We showed that both HIV-1 and HTLV-1 cell-free particles are poorly efficient at productively infecting DCs, except when DC-SIGN has been engaged. Furthermore, while SAMHD-1 accounts for restriction of cell-free HIV-1 infection, it is not involved in HTLV-1 restriction. In addition, cell-free viruses lead mainly to a nonproductive DC infection, leading to trans-infection of T-cells, a process important for HIV-1 spread but not for that of HTLV-1. Finally, we show that T-DC cell-to-cell transfer implies viral trafficking in vesicles that may both increase productive infection of DCs ("cis-infection") and allow viral escape from immune surveillance. Altogether, these observations allowed us to draw a model of HTLV-1 and HIV-1 trafficking in DCs.
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113
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Abstract
Rice reoviruses, transmitted by leafhopper or planthopper vectors in a persistent propagative manner, seriously threaten the stability of rice production in Asia. Understanding the mechanisms that enable viral transmission by insect vectors is a key to controlling these viral diseases. This review describes current understanding of replication cycles of rice reoviruses in vector cell lines, transmission barriers, and molecular determinants of vector competence and persistent infection. Despite recent breakthroughs, such as the discoveries of actin-based tubule motility exploited by viruses to overcome transmission barriers and mutually beneficial relationships between viruses and bacterial symbionts, there are still many gaps in our knowledge of transmission mechanisms. Advances in genome sequencing, reverse genetics systems, and molecular technologies will help to address these problems. Investigating the multiple interaction systems among the virus, insect vector, insect symbiont, and plant during natural infection in the field is a central topic for future research on rice reoviruses.
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Affiliation(s)
- Taiyun Wei
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, People's Republic of China;
| | - Yi Li
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China;
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114
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Viruses exploit the tissue physiology of the host to spread in vivo. Curr Opin Cell Biol 2016; 41:81-90. [PMID: 27149407 DOI: 10.1016/j.ceb.2016.04.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/11/2016] [Accepted: 04/20/2016] [Indexed: 02/07/2023]
Abstract
Viruses are pathogens that strictly depend on their host for propagation. Over years of co-evolution viruses have become experts in exploiting the host cell biology and physiology to ensure efficient replication and spread. Here, we will first summarize the concepts that have emerged from in vitro cell culture studies to understand virus spread. We will then review the results from studies in living animals that reveal how viruses exploit the natural flow of body fluids, specific tissue architecture, and patterns of cell circulation and migration to spread within the host. Understanding tissue physiology will be critical for the design of antiviral strategies that prevent virus dissemination.
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115
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Porcine Reproductive and Respiratory Syndrome Virus Utilizes Nanotubes for Intercellular Spread. J Virol 2016; 90:5163-5175. [PMID: 26984724 DOI: 10.1128/jvi.00036-16] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 03/09/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Intercellular nanotube connections have been identified as an alternative pathway for cellular spreading of certain viruses. In cells infected with porcine reproductive and respiratory syndrome virus (PRRSV), nanotubes were observed connecting two distant cells with contiguous membranes, with the core infectious viral machinery (viral RNA, certain replicases, and certain structural proteins) present in/on the intercellular nanotubes. Live-cell movies tracked the intercellular transport of a recombinant PRRSV that expressed green fluorescent protein (GFP)-tagged nsp2. In MARC-145 cells expressing PRRSV receptors, GFP-nsp2 moved from one cell to another through nanotubes in the presence of virus-neutralizing antibodies. Intercellular transport of viral proteins did not require the PRRSV receptor as it was observed in receptor-negative HEK-293T cells after transfection with an infectious clone of GFP-PRRSV. In addition, GFP-nsp2 was detected in HEK-293T cells cocultured with recombinant PRRSV-infected MARC-145 cells. The intercellular nanotubes contained filamentous actin (F-actin) with myosin-associated motor proteins. The F-actin and myosin IIA were identified as coprecipitates with PRRSV nsp1β, nsp2, nsp2TF, nsp4, nsp7-nsp8, GP5, and N proteins. Drugs inhibiting actin polymerization or myosin IIA activation prevented nanotube formation and viral clusters in virus-infected cells. These data lead us to propose that PRRSV utilizes the host cell cytoskeletal machinery inside nanotubes for efficient cell-to-cell spread. This form of virus transport represents an alternative pathway for virus spread, which is resistant to the host humoral immune response. IMPORTANCE Extracellular virus particles transmit infection between organisms, but within infected hosts intercellular infection can be spread by additional mechanisms. In this study, we describe an alternative pathway for intercellular transmission of PRRSV in which the virus uses nanotube connections to transport infectious viral RNA, certain replicases, and certain structural proteins to neighboring cells. This process involves interaction of viral proteins with cytoskeletal proteins that form the nanotube connections. Intercellular viral spread through nanotubes allows the virus to escape the neutralizing antibody response and may contribute to the pathogenesis of viral infections. The development of strategies that interfere with this process could be critical in preventing the spread of viral infection.
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116
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HIV-1-Induced Small T Cell Syncytia Can Transfer Virus Particles to Target Cells through Transient Contacts. Viruses 2015; 7:6590-603. [PMID: 26703714 PMCID: PMC4690882 DOI: 10.3390/v7122959] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 11/27/2015] [Accepted: 12/02/2015] [Indexed: 12/28/2022] Open
Abstract
HIV-1 Env mediates fusion of viral and target cell membranes, but it can also mediate fusion of infected (producer) and target cells, thus triggering the formation of multinucleated cells, so-called syncytia. Large, round, immobile syncytia are readily observable in cultures of HIV-1-infected T cells, but these fast growing “fusion sinks” are largely regarded as cell culture artifacts. In contrast, small HIV-1-induced syncytia were seen in the paracortex of peripheral lymph nodes and other secondary lymphoid tissue of HIV-1-positive individuals. Further, recent intravital imaging of lymph nodes in humanized mice early after their infection with HIV-1 demonstrated that a significant fraction of infected cells were highly mobile, small syncytia, suggesting that these entities contribute to virus dissemination. Here, we report that the formation of small, migratory syncytia, for which we provide further quantification in humanized mice, can be recapitulated in vitro if HIV-1-infected T cells are placed into 3D extracellular matrix (ECM) hydrogels rather than being kept in traditional suspension culture systems. Intriguingly, live-cell imaging in hydrogels revealed that these syncytia, similar to individual infected cells, can transiently interact with uninfected cells, leading to rapid virus transfer without cell-cell fusion. Infected cells were also observed to deposit large amounts of viral particles into the extracellular space. Altogether, these observations suggest the need to further evaluate the biological significance of small, T cell-based syncytia and to consider the possibility that these entities do indeed contribute to virus spread and pathogenesis.
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117
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Miao C, Li M, Zheng YM, Cohen FS, Liu SL. Cell-cell contact promotes Ebola virus GP-mediated infection. Virology 2015; 488:202-15. [PMID: 26655238 DOI: 10.1016/j.virol.2015.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 11/18/2015] [Accepted: 11/19/2015] [Indexed: 10/22/2022]
Abstract
Ebola virus (EBOV) is a highly pathogenic filovirus that causes hemorrhagic fever in humans and animals. Here we provide evidence that cell-cell contact promotes infection mediated by the glycoprotein (GP) of EBOV. Interestingly, expression of EBOV GP alone, even in the absence of retroviral Gag-Pol, is sufficient to transfer a retroviral vector encoding Tet-off from cell to cell. Cell-to-cell infection mediated by EBOV GP is blocked by inhibitors of actin polymerization, but appears to be less sensitive to KZ52 neutralization. Treatment of co-cultured cells with cathepsin B/L inhibitors, or an entry inhibitor 3.47 that targets the receptor NPC1 for virus binding, also blocks cell-to-cell infection. Cell-cell contact also enhances spread of rVSV bearing GP in monocytes and macrophages, the primary targets of natural EBOV infection. Altogether, our study reveals that cell-cell contact promotes EBOV GP-mediated infection, and provides new insight into understanding EBOV spread and viral pathogenesis.
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Affiliation(s)
- Chunhui Miao
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Minghua Li
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Yi-Min Zheng
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Fredric S Cohen
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, IL 60612, USA
| | - Shan-Lu Liu
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.
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118
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Roa-Linares VC, Brand YM, Agudelo-Gomez LS, Tangarife-Castaño V, Betancur-Galvis LA, Gallego-Gomez JC, González MA. Anti-herpetic and anti-dengue activity of abietane ferruginol analogues synthesized from (+)-dehydroabietylamine. Eur J Med Chem 2015; 108:79-88. [PMID: 26638041 PMCID: PMC7115619 DOI: 10.1016/j.ejmech.2015.11.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 09/23/2015] [Accepted: 11/05/2015] [Indexed: 01/12/2023]
Abstract
The abietane-type diterpenoid (+)-ferruginol (1), a bioactive compound isolated from several plants, has attracted much attention as consequence of its pharmacological properties, which includes antibacterial, antifungal, antimicrobial, cardioprotective, anti-oxidative, anti-plasmodial, leishmanicidal, anti-ulcerogenic, anti-inflammatory and antitumor actions. In this study, we report on the antiviral evaluation of ferruginol (1) and several analogues synthesized from commercial (+)-dehydroabietylamine. Thus, the activity against Human Herpesvirus type 1, Human Herpesvirus type 2 and Dengue Virus type 2, was studied. Two ferruginol analogues showed high antiviral selectivity index and reduced viral plaque-size in post-infection stages against both Herpes and Dengue viruses. A promising lead, compound 8, was ten-fold more potent (EC50 = 1.4 μM) than the control ribavirin against Dengue Virus type 2. Our findings suggest that the 12-hydroxyabieta-8,11,13-triene skeleton, which is characteristic of the diterpenoid ferruginol (1), is an interesting molecular scaffold for development of novel antivirals. In addition, the cytotoxic and antifungal activities of the synthesized ferruginol analogues have also been investigated. (©)20155 Elsevier Science. All rights reserved.
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Affiliation(s)
- Vicky C Roa-Linares
- Group of Investigative Dermatology, Institute of Medical Research, Medicine Faculty, University of Antioquia, Medellin, A.A1226, Antioquia, Colombia; Translational and Molecular Medicine Group, Institute of Medical Research, Medicine Faculty, University of Antioquia, Medellin, Colombia
| | - Yaneth M Brand
- Group of Investigative Dermatology, Institute of Medical Research, Medicine Faculty, University of Antioquia, Medellin, A.A1226, Antioquia, Colombia; Translational and Molecular Medicine Group, Institute of Medical Research, Medicine Faculty, University of Antioquia, Medellin, Colombia
| | - Lee S Agudelo-Gomez
- Group of Investigative Dermatology, Institute of Medical Research, Medicine Faculty, University of Antioquia, Medellin, A.A1226, Antioquia, Colombia
| | - Verónica Tangarife-Castaño
- Group of Investigative Dermatology, Institute of Medical Research, Medicine Faculty, University of Antioquia, Medellin, A.A1226, Antioquia, Colombia
| | - Liliana A Betancur-Galvis
- Group of Investigative Dermatology, Institute of Medical Research, Medicine Faculty, University of Antioquia, Medellin, A.A1226, Antioquia, Colombia; Translational and Molecular Medicine Group, Institute of Medical Research, Medicine Faculty, University of Antioquia, Medellin, Colombia
| | - Juan C Gallego-Gomez
- Translational and Molecular Medicine Group, Institute of Medical Research, Medicine Faculty, University of Antioquia, Medellin, Colombia
| | - Miguel A González
- Departamento de Química Orgánica, Universidad de Valencia, E-46100 Burjassot, Valencia, Spain.
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119
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Abstract
Rigorous testing of new HIV-prevention strategies is a time-consuming and expensive undertaking. Thus, making well informed decisions on which candidate-prevention approaches are most likely to provide the most benefit is critical to appropriately prioritizing clinical testing. In the case of biological interventions, the decision to test a given prevention approach in human trials rests largely on evidence of protection in preclinical studies. The ability of preclinical studies to predict efficacy in humans may depend on how well the model recapitulates key biological features of HIV transmission relevant to the question at hand. Here, we review our current understanding of the biology of HIV transmission based on data from animal models, cell culture, and viral sequence analysis from human infection. We summarize studies of the bottleneck in viral transmission; the characteristics of transmitted viruses; the establishment of infection; and the contribution of cell-free and cell-associated virus. We seek to highlight the implications of HIV-transmission biology for development of prevention interventions, and to discuss the limitations of existing preclinical models.
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120
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Magnus C, Reh L, Trkola A. HIV-1 resistance to neutralizing antibodies: Determination of antibody concentrations leading to escape mutant evolution. Virus Res 2015; 218:57-70. [PMID: 26494166 DOI: 10.1016/j.virusres.2015.10.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/07/2015] [Accepted: 10/07/2015] [Indexed: 11/15/2022]
Abstract
Broadly neutralizing antibodies against human immunodeficiency virus type 1 (HIV-1) are considered vital components of novel therapeutics and blueprints for vaccine research. Yet escape to even the most potent of these antibodies is imminent in natural infection. Measures to define antibody efficacy and prevent mutant selection are thus urgently needed. Here, we derive a mathematical framework to predict the concentration ranges for which antibody escape variants can outcompete their viral ancestors, referred to as mutant selection window (MSW). When determining the MSW, we focus on the differential efficacy of neutralizing antibodies against HIV-1 in two canonical infection routes, free-virus infection and cell-cell transmission. The latter has proven highly effective in vitro suggesting its importance for both in vivo spread as well as for escaping targeted intervention strategies. We observed a range of MSW patterns that highlight the potential of mutants to arise in both transmission pathways and over wide concentration ranges. Most importantly, we found that only when the arising mutant has both, residual sensitivity to the neutralizing antibody and reduced infectivity compared to the parental virus, antibody dosing outside of the MSW to restrict mutant selection is possible. Emergence of mutants that provide complete escape and have no considerable fitness loss cannot be prevented by adjusting antibody doses. The latter may in part explain the ubiquitous resistance to neutralizing antibodies observed in natural infection and antibody treatment. Based on our findings, combinations of antibodies targeting different epitopes should be favored for antibody-based interventions as this may render complete resistance less likely to occur and also increase chances that multiple escapes result in severe fitness loss of the virus making longer-term antibody treatment more feasible.
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Affiliation(s)
- Carsten Magnus
- Institute of Medical Virology, University of Zurich, Switzerland; Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland.
| | - Lucia Reh
- Institute of Medical Virology, University of Zurich, Switzerland.
| | - Alexandra Trkola
- Institute of Medical Virology, University of Zurich, Switzerland.
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121
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Ni C, Huang L, Chen Y, He M, Hu Y, Liu S, Fang X, Li J, Sun Q, Wang X. Implication of cell-in-cell structures in the transmission of HIV to epithelial cells. Cell Res 2015; 25:1265-8. [PMID: 26427717 DOI: 10.1038/cr.2015.119] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Affiliation(s)
- Chao Ni
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006 & Institute of Life Sciences & Municipal Key Laboratory of Geriatric, Chinese PLA General Hospital, the State Key Laboratory of Kidney, Beijing 100853, China
| | - Lei Huang
- 302 Military Hospital of China, Beijing 100039, China
| | - Yuhui Chen
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006 & Institute of Life Sciences & Municipal Key Laboratory of Geriatric, Chinese PLA General Hospital, the State Key Laboratory of Kidney, Beijing 100853, China
| | - Meifang He
- The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510080, China
| | - Yazhuo Hu
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006 & Institute of Life Sciences & Municipal Key Laboratory of Geriatric, Chinese PLA General Hospital, the State Key Laboratory of Kidney, Beijing 100853, China
| | - Siyang Liu
- Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Xiangdong Fang
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jingyun Li
- Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Qiang Sun
- Institute of Biotechnology, 20 Dongdajie, Beijing 100071, China
| | - Xiaoning Wang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006 & Institute of Life Sciences & Municipal Key Laboratory of Geriatric, Chinese PLA General Hospital, the State Key Laboratory of Kidney, Beijing 100853, China
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122
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Yu J, Li M, Wilkins J, Ding S, Swartz TH, Esposito AM, Zheng YM, Freed EO, Liang C, Chen BK, Liu SL. IFITM Proteins Restrict HIV-1 Infection by Antagonizing the Envelope Glycoprotein. Cell Rep 2015; 13:145-156. [PMID: 26387945 PMCID: PMC4602366 DOI: 10.1016/j.celrep.2015.08.055] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 06/16/2015] [Accepted: 08/19/2015] [Indexed: 01/08/2023] Open
Abstract
The interferon-induced transmembrane (IFITM) proteins have been recently shown to restrict HIV-1 and other viruses. Here, we provide evidence that IFITM proteins, particularly IFITM2 and IFITM3, specifically antagonize the HIV-1 envelope glycoprotein (Env), thereby inhibiting viral infection. IFITM proteins interact with HIV-1 Env in viral producer cells, leading to impaired Env processing and virion incorporation. Notably, the level of IFITM incorporation into HIV-1 virions does not strictly correlate with the extent of inhibition. Prolonged passage of HIV-1 in IFITM-expressing T lymphocytes leads to emergence of Env mutants that overcome IFITM restriction. The ability of IFITMs to inhibit cell-to-cell infection can be extended to HIV-1 primary isolates, HIV-2 and SIVs; however, the extent of inhibition appears to be virus-strain dependent. Overall, our study uncovers a mechanism by which IFITM proteins specifically antagonize HIV-1 Env to restrict HIV-1 infection and provides insight into the specialized role of IFITMs in HIV infection. IFITMs inhibit HIV-1 cell-to-cell infection and impair viral infectivity IFITMs specifically interact with HIV-1 Env and inhibit Env processing IFITM incorporation into HIV-1 virions does not correlate with inhibition IFITM inhibition of primate lentiviruses is virus-strain specific
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Affiliation(s)
- Jingyou Yu
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Minghua Li
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Jordan Wilkins
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Shilei Ding
- McGill AIDS Centre, Lady Davis Institute, Montreal, QC H3T 1E2, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC H3A 2B4, Canada
| | - Talia H Swartz
- Division of Infectious Diseases, Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Anthony M Esposito
- Division of Infectious Diseases, Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Yi-Min Zheng
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Eric O Freed
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, National Cancer Institute-Frederick, Frederick, MD 21702, USA
| | - Chen Liang
- McGill AIDS Centre, Lady Davis Institute, Montreal, QC H3T 1E2, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC H3A 2B4, Canada
| | - Benjamin K Chen
- Division of Infectious Diseases, Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Shan-Lu Liu
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.
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123
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Shimura K, Miyazato P, Oishi S, Fujii N, Matsuoka M. Impact of HIV-1 infection pathways on susceptibility to antiviral drugs and on virus spread. Virology 2015; 484:364-376. [PMID: 26186575 DOI: 10.1016/j.virol.2015.06.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Revised: 06/08/2015] [Accepted: 06/26/2015] [Indexed: 11/19/2022]
Abstract
The infection routes of HIV-1 can affect several viral properties, including dissemination, pathogenesis, and immune evasion. In this study, we evaluated the inhibitory activity of a wide variety of anti-HIV drugs, focusing on the impact that different infection pathways have on their efficacy. Compared to cell-free infection, inhibitory activities were reduced in cell-to-cell productive transmission for all drugs tested. We detected weak reporter-expressing target cells after cell-to-cell transmission in the presence of integrase strand transfer inhibitors (INSTIs). Further analysis revealed that this expression was mainly due to unintegrated circular HIV (cHIV) DNAs, consisting of 1-LTR and 2-LTR circles. When in vitro-constructed cHIV DNAs were introduced into cells, the production of infectious and intercellular transmittable virions was observed, suggesting that cHIV DNA could be a source of infectious virus. These results highlight some advantages of the cell-to-cell infection mode for viral expansion, particularly in the presence of anti-retroviral drugs.
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Affiliation(s)
- Kazuya Shimura
- Institute for Virus Research, Kyoto University, Kyoto, Japan.
| | - Paola Miyazato
- Institute for Virus Research, Kyoto University, Kyoto, Japan
| | - Shinya Oishi
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Nobutaka Fujii
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Masao Matsuoka
- Institute for Virus Research, Kyoto University, Kyoto, Japan
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124
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Rizkallah G, Mahieux R, Dutartre H. [Intercellular transmission of HTLV-1: not all mechanisms have been revealed]. Med Sci (Paris) 2015; 31:629-37. [PMID: 26152167 DOI: 10.1051/medsci/20153106016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
HTLV-1 is the etiological agent of Adult T cell Leukemia/Lymphoma (ATLL) and of HTLV-1-Associated Myelopathy/tropical spastic paraparesis (HAM/TSP). It is mainly detected in CD4+ lymphocytes in vivo, but proviral genomes have also been detected although less frequently, in CD8+ T lymphocytes, B lymphocytes, monocytes, macrophages, dendritic cells and other non-lymphoid cells. Virus spread is highly dependent on cell-cell contact. This mode of transmission is correlated with an increased ability of infected cells to migrate, a property linked to cytoskeleton reorganization induced by the viral Tax protein. Cell-to-cell transmission relies on at least three non-exclusive molecular pathways. First, a specialized area, the "virological synapse'' (VS) promotes direct transmission of budding HTLV-1 particles into a synaptic cleft formed between infected and uninfected cells. Second, HTLV-1 particles accumulate at the plasma membrane of infected cells in a biofilm-like extracellular viral assembly that resembles a bacterial biofilm. Viral biofilm is rapidly transmitted to uninfected cells when infected cells contact target cells. Finally, membrane extensions called inter-cellular conduits facilitate HTLV-1 proteins transfer from infected to uninfected target cells, and may stabilize cell-cell contacts. The aim of this review is to summarize the molecular mechanisms of these HTLV-1 transmission pathways.
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Affiliation(s)
- Gerges Rizkallah
- Équipe oncogenèse rétrovirale ; équipe labellisée Ligue nationale contre le cancer ; centre international de recherche en infectiologie, Inserm U1111-CNRS UMR5308, Lyon, France - École normale supérieure de Lyon, 46, allée d'Italie, 69007 Lyon, France - Université Lyon 1, Lyon Cedex 07, 69364, France
| | - Renaud Mahieux
- Équipe oncogenèse rétrovirale ; équipe labellisée Ligue nationale contre le cancer ; centre international de recherche en infectiologie, Inserm U1111-CNRS UMR5308, Lyon, France - École normale supérieure de Lyon, 46, allée d'Italie, 69007 Lyon, France - Université Lyon 1, Lyon Cedex 07, 69364, France
| | - Hélène Dutartre
- Équipe oncogenèse rétrovirale ; équipe labellisée Ligue nationale contre le cancer ; centre international de recherche en infectiologie, Inserm U1111-CNRS UMR5308, Lyon, France - École normale supérieure de Lyon, 46, allée d'Italie, 69007 Lyon, France - Université Lyon 1, Lyon Cedex 07, 69364, France
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125
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Yang CF, Tu CH, Lo YP, Cheng CC, Chen WJ. Involvement of Tetraspanin C189 in Cell-to-Cell Spreading of the Dengue Virus in C6/36 Cells. PLoS Negl Trop Dis 2015; 9:e0003885. [PMID: 26132143 PMCID: PMC4488468 DOI: 10.1371/journal.pntd.0003885] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 06/09/2015] [Indexed: 01/23/2023] Open
Abstract
Dengue virus (DENV) is naturally transmitted by mosquitoes to humans, infecting cells of both hosts. Unlike in mammalian cells, DENV usually does not cause extremely deleterious effects on cells of mosquitoes. Despite this, clustered progeny virions were found to form infection foci in a high density cell culture. It is thus interesting to know how the virus spreads among cells in tissues such as the midgut within live mosquitoes. This report demonstrates that cell-to-cell spread is one way for DENV to infect neighboring cells without depending on the "release and entry" mode. In the meantime, a membrane-bound vacuole incorporating tetraspanin C189 was formed in response to DENV infection in the C6/36 cell and was subsequently transported along with the contained virus from one cell to another. Knockdown of C189 in DENV-infected C6/36 cells is shown herein to reduce cell-to-cell transmission of the virus, which may be recovered by co-transfection with a C189-expressing vector in DENV-infected C6/36 cells. Moreover, cell-to-cell transmission usually occurred at the site where the donor cell directly contacts the recipient cell. It suggested that C189 is crucially involved in the intercellular spread of progeny viral particles between mosquito cells. This novel finding presumably accounts for the rapid and efficient infection of DENV after its initial replication within tissues of the mosquito.
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Affiliation(s)
- Chao-Fu Yang
- Graduate Institute of Biomedical Science, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan
| | - Cheng-Hsun Tu
- Graduate Institute of Biomedical Science, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan
| | - Yin-Ping Lo
- Graduate Institute of Biomedical Science, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan
| | - Chih-Chieh Cheng
- Graduate Institute of Biomedical Science, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan
| | - Wei-June Chen
- Graduate Institute of Biomedical Science, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan
- Department of Public Health and Parasitology, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan
- * E-mail:
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126
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Mori K, Murano K, Ohniwa RL, Kawaguchi A, Nagata K. Oseltamivir expands quasispecies of influenza virus through cell-to-cell transmission. Sci Rep 2015; 5:9163. [PMID: 25772381 PMCID: PMC4649863 DOI: 10.1038/srep09163] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 02/09/2015] [Indexed: 12/16/2022] Open
Abstract
The population of influenza virus consists of a huge variety of variants, called quasispecies, due to error-prone replication. Previously, we reported that progeny virions of influenza virus become infected to adjacent cells via cell-to-cell transmission pathway in the presence of oseltamivir. During cell-to-cell transmission, viruses become infected to adjacent cells at high multiplicity since progeny virions are enriched on plasma membrane between infected cells and their adjacent cells. Co-infection with viral variants may rescue recessive mutations with each other. Thus, it is assumed that the cell-to-cell transmission causes expansion of virus quasispecies. Here, we have demonstrated that temperature-sensitive mutations remain in progeny viruses even at non-permissive temperature by co-infection in the presence of oseltamivir. This is possibly due to a multiplex infection through the cell-to-cell transmission by the addition of oseltamivir. Further, by the addition of oseltamivir, the number of missense mutation introduced by error-prone replication in segment 8 encoding NS1 was increased in a passage-dependent manner. The number of missense mutation in segment 5 encoding NP was not changed significantly, whereas silent mutation was increased. Taken together, we propose that oseltamivir expands influenza virus quasispecies via cell-to-cell transmission, and may facilitate the viral evolution and adaptation.
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Affiliation(s)
- Kotaro Mori
- Department of Infection Biology, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Kensaku Murano
- Department of Infection Biology, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Ryosuke L Ohniwa
- Division of Biomedical Science, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Atsushi Kawaguchi
- Department of Infection Biology, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Kyosuke Nagata
- Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
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127
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Agosto LM, Uchil PD, Mothes W. HIV cell-to-cell transmission: effects on pathogenesis and antiretroviral therapy. Trends Microbiol 2015; 23:289-95. [PMID: 25766144 DOI: 10.1016/j.tim.2015.02.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/30/2015] [Accepted: 02/09/2015] [Indexed: 02/07/2023]
Abstract
HIV spreads more efficiently in vitro when infected cells directly contact uninfected cells to form virological synapses. A hallmark of virological synapses is that viruses can be transmitted at a higher multiplicity of infection (MOI) that, in vitro, results in a higher number of proviruses. Whether HIV also spreads by cell-cell contact in vivo is a matter of debate. Here we discuss recent data that suggest that contact-mediated transmission largely manifests itself in vivo as CD4+ T cell depletion. The assault of a cell by a large number of incoming particles is likely to be efficiently sensed by the innate cellular surveillance to trigger cell death. The large number of particles transferred across virological synapses has also been implicated in reduced efficacy of antiretroviral therapies. Thus, antiretroviral therapies must remain effective against the high MOI observed during cell-to-cell transmission to inhibit both viral replication and the pathogenesis associated with HIV infection.
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Affiliation(s)
- Luis M Agosto
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536, USA; Department of Medicine, Section of Infectious Diseases, Boston University School of Medicine, Boston, MA 02118, USA.
| | - Pradeep D Uchil
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536, USA.
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128
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van Riel D, Verdijk R, Kuiken T. The olfactory nerve: a shortcut for influenza and other viral diseases into the central nervous system. J Pathol 2015; 235:277-87. [PMID: 25294743 DOI: 10.1002/path.4461] [Citation(s) in RCA: 259] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 10/03/2014] [Indexed: 02/01/2023]
Abstract
The olfactory nerve consists mainly of olfactory receptor neurons and directly connects the nasal cavity with the central nervous system (CNS). Each olfactory receptor neuron projects a dendrite into the nasal cavity on the apical side, and on the basal side extends its axon through the cribriform plate into the olfactory bulb of the brain. Viruses that can use the olfactory nerve as a shortcut into the CNS include influenza A virus, herpesviruses, poliovirus, paramyxoviruses, vesicular stomatitis virus, rabies virus, parainfluenza virus, adenoviruses, Japanese encephalitis virus, West Nile virus, chikungunya virus, La Crosse virus, mouse hepatitis virus, and bunyaviruses. However, mechanisms of transport via the olfactory nerve and subsequent spread through the CNS are poorly understood. Proposed mechanisms are either infection of olfactory receptor neurons themselves or diffusion through channels formed by olfactory ensheathing cells. Subsequent virus spread through the CNS could occur by multiple mechanisms, including trans-synaptic transport and microfusion. Viral infection of the CNS can lead to damage from infection of nerve cells per se, from the immune response, or from a combination of both. Clinical consequences range from nervous dysfunction in the absence of histopathological changes to severe meningoencephalitis and neurodegenerative disease.
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Affiliation(s)
- Debby van Riel
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
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129
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Anderson DJ. Modeling mucosal cell-associated HIV type 1 transmission in vitro. J Infect Dis 2015; 210 Suppl 3:S648-53. [PMID: 25414419 DOI: 10.1093/infdis/jiu537] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) can efficiently spread by direct cell-to-cell contact, a mechanism termed cell-associated HIV transmission. By some estimates, cell-associated HIV transmission is 10-1000-fold more effective than cell-free HIV infection. Mucosal cell-associated HIV transmission may occur when HIV-bearing cells in mucosal secretions from an HIV-infected donor transfer virus directly to recipient target cells in or below the mucosal epithelium, or through HIV transcytosis across the mucosal epithelium of a noninfected host. This mechanism may play an important role in the sexual and vertical transmission of HIV-1, yet most in vitro tests of vaccine and microbicide efficacy assess cell-free virus transmission. This article reviews in vitro assays that have been used to model mucosal cell-associated transmission, including microscopy, immune cell cocultures, use of HIV-infected cells in epithelial cell transcytosis assays, and cell-associated infection of mucosal tissue explants. Assays that authentically simulate mucosal cell-associated HIV transmission could provide valuable insight into mechanisms and molecules that can potentially be targeted for HIV prevention, as well as critical models for testing novel HIV prevention strategies for efficacy against cell-associated HIV transmission.
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Affiliation(s)
- Deborah J Anderson
- Department of Obstetrics and GynecologyDepartment of MicrobiologyDepartment of Medicine, Boston University School of Medicine, Massachusetts
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130
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Cruz-Oliveira C, Freire JM, Conceição TM, Higa LM, Castanho MARB, Da Poian AT. Receptors and routes of dengue virus entry into the host cells. FEMS Microbiol Rev 2014; 39:155-70. [PMID: 25725010 DOI: 10.1093/femsre/fuu004] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Dengue is the most prevalent arthropod-borne viral disease, caused by dengue virus, a member of the Flaviviridae family. Its worldwide incidence is now a major health problem, with 2.5 billion people living in risk areas. In this review, we integrate the structural rearrangements of each viral protein and their functions in all the steps of virus entry into the host cells. We describe in detail the putative receptors and attachment factors in mammalian and mosquito cells, and the recognition of viral immunocomplexes via Fcγ receptor in immune cells. We also discuss that virus internalization might occur through distinct entry pathways, including clathrin-mediated or non-classical clathrin-independent endocytosis, depending on the host cell and virus serotype or strain. The implications of viral maturation in virus entry are also explored. Finally, we discuss the mechanisms of viral genome access to the cytoplasm. This includes the role of low pH-induced conformational changes in the envelope protein that mediate membrane fusion, and original insights raised by our recent work that supports the hypothesis that capsid protein would also be an active player in this process, acting on viral genome translocation into the cytoplasm.
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Affiliation(s)
- Christine Cruz-Oliveira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - João Miguel Freire
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal
| | - Thaís M Conceição
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Luiza M Higa
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Miguel A R B Castanho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal
| | - Andrea T Da Poian
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
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131
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Abstract
UNLABELLED In the extracellular environment, cell-free virions seek out naive host cells over long distances and between organisms. This is the primary mechanism of spread for most viruses. Here we provide evidence for an alternative pathway previously undescribed for orthomyxoviruses, whereby the spread of influenza A virus (IAV) infectious cores to neighboring cells can occur within intercellular connections. The formation of these connections requires actin dynamics and is enhanced by viral infection. Connected cells have contiguous membranes, and the core infectious viral machinery (RNP and polymerase) was present inside the intercellular connections. A live-cell movie of green fluorescent protein (GFP)-tagged NS1 of IAV shows viral protein moving from one cell to another through an intercellular connection. The movement of tagged protein was saltatory but overall traveled only in one direction. Infectious virus cores can move from one cell to another without budding and release of cell-free virions, as evidenced by the finding that whereas a neuraminidase inhibitor alone did not inhibit the development of IAV microplaques, the presence of a neuraminidase inhibitor together with drugs inhibiting actin dynamics or the microtubule stabilizer paclitaxel (originally named taxol) precluded microplaque formation. Similar results were also observed with parainfluenza virus 5 (PIV5), a paramyxovirus, when neutralizing antibody was used to block spread by cell-free virions. Intercellular spread of infectious core particles was unaffected or enhanced in the presence of nocodazole for IAV but inhibited for PIV5. The intercellular connections have a core of filamentous actin, which hints toward transport of virus particles through the use of a myosin motor. IMPORTANCE Here we describe a new method by which influenza A virus (IAV) spreads from cell to cell: IAV uses intracellular connections. The formation of these connections requires actin dynamics and is enhanced by viral infection and the absence of microtubules. Connected cells appeared to have contiguous membranes, and the core infectious viral machinery (RNP and polymerase) was present inside the intercellular connections. Infectious virus cores can move from one cell to another without budding and release of cell-free virions. Similar results were also observed with parainfluenza virus 5 (PIV5).
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Brandenberg OF, Rusert P, Magnus C, Weber J, Böni J, Günthard HF, Regoes RR, Trkola A. Partial rescue of V1V2 mutant infectivity by HIV-1 cell-cell transmission supports the domain's exceptional capacity for sequence variation. Retrovirology 2014; 11:75. [PMID: 25287422 PMCID: PMC4190450 DOI: 10.1186/s12977-014-0075-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 08/13/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Variable loops 1 and 2 (V1V2) of the HIV-1 envelope glycoprotein gp120 perform two key functions: ensuring envelope trimer entry competence and shielding against neutralizing antibodies. While preserving entry functionality would suggest a high need for V1V2 sequence optimization and conservation, shielding efficacy is known to depend on a high flexibility of V1V2 giving rise to its substantial sequence variability. How entry competence of the trimer is maintained despite the continuous emergence of antibody escape mutations within V1V2 has not been resolved. Since HIV cell-cell transmission is considered a highly effective means of virus dissemination, we investigated whether cell-cell transmission may serve to enhance infectivity of V1V2 variants with debilitated free virus entry. RESULTS In a detailed comparison of wt and V1V2 mutant envelopes, V1V2 proved to be a key factor in ascertaining free virus infectivity, with V1V2 mutants displaying significantly reduced trimer integrity. Despite these defects, cell-cell transmission was able to partially rescue infectivity of V1V2 mutant viruses. We identified two regions, encompassing amino acids 156 to 160 (targeted by broadly neutralizing antibodies) and 175 to 180 (encompassing the α4β7 binding site) which were particularly prone to free virus infectivity loss upon mutation but maintained infectivity in cell-cell transmission. Of note, V1V2 antibody shielding proved important during both free virus infection and cell-cell transmission. CONCLUSIONS Based on our data we propose a model for V1V2 evolution that centers on cell-cell transmission as a salvage pathway for virus replication. Escape from antibody neutralization may frequently result in V1V2 mutations that reduce free virus infectivity. Cell-cell transmission could provide these escape viruses with sufficiently high replication levels that enable selection of compensatory mutations, thereby restoring free virus infectivity while ensuring antibody escape. Thus, our study highlights the need to factor in cell-cell transmission when considering neutralization escape pathways of HIV-1.
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133
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Fitness impaired drug resistant HIV-1 is not compromised in cell-to-cell transmission or establishment of and reactivation from latency. Viruses 2014; 6:3487-99. [PMID: 25243372 PMCID: PMC4189035 DOI: 10.3390/v6093487] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 09/01/2014] [Accepted: 09/17/2014] [Indexed: 12/24/2022] Open
Abstract
Both the presence of latently infected cells and cell-to-cell viral transmission are means whereby HIV can partially evade the inhibitory activities of antiretroviral drugs. The clinical use of a novel integrase inhibitor, dolutegravir (DTG), has established hope that this compound may limit HIV persistence, since no treatment-naïve patient treated with DTG has yet developed resistance against this drug, even though a R263K substitution in integrase confers low-level resistance to this drug in tissue culture. Here, we have studied the impact of R263K on HIV replication capacity and the ability of HIV to establish or be reactivated from latency and/or spread through cell-to-cell transmission. We affirm that DTG-resistant viruses have diminished capacity to replicate and establish infection. However, DTG-resistant viruses were efficiently transmitted via cell-to-cell contacts, and were as likely to establish and be reactivated from latent infection as wildtype viruses. Both cell-to-cell transmission of HIV and the establishment of and reemergence from latency are important for the establishment and maintenance of viral reservoirs. Since the DTG and other drug-resistant viruses studied here do not seem to have been impaired in regard to these activities, studies should be undertaken to characterize HIV reservoirs in patients who have been treated with DTG.
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134
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Adding new dimensions: towards an integrative understanding of HIV-1 spread. Nat Rev Microbiol 2014; 12:563-74. [PMID: 25029025 DOI: 10.1038/nrmicro3309] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In vitro studies in primary or immortalized cells continue to be used to elucidate the essential principles that govern the interactions between HIV-1 and isolated target cells. However, until recently, substantial technical barriers prevented this information from being efficiently translated to the more complex scenario of HIV-1 spread in the host in vivo, which has limited our understanding of the impact of host physiological parameters on the spread of HIV-1. In this Review, we discuss the recent development of imaging approaches to visualize HIV-1 spread and the adaptation of these approaches to organotypic ex vivo models and animal models. We focus on new concepts, including the mechanisms and in vivo relevance of cell-cell transmission for HIV-1 spread and the function of the HIV-1 pathogenesis factor Nef, which have emerged from the application of these integrative approaches in complex cell systems.
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135
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Risco C, de Castro IF, Sanz-Sánchez L, Narayan K, Grandinetti G, Subramaniam S. Three-Dimensional Imaging of Viral Infections. Annu Rev Virol 2014; 1:453-73. [PMID: 26958730 DOI: 10.1146/annurev-virology-031413-085351] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Three-dimensional (3D) imaging technologies are beginning to have significant impact in the field of virology, as they are helping us understand how viruses take control of cells. In this article we review several methodologies for 3D imaging of cells and show how these technologies are contributing to the study of viral infections and the characterization of specialized structures formed in virus-infected cells. We include 3D reconstruction by transmission electron microscopy (TEM) using serial sections, electron tomography, and focused ion beam scanning electron microscopy (FIB-SEM). We summarize from these methods selected contributions to our understanding of viral entry, replication, morphogenesis, egress and propagation, and changes in the spatial architecture of virus-infected cells. In combination with live-cell imaging, correlative microscopy, and new techniques for molecular mapping in situ, the availability of these methods for 3D imaging is expected to provide deeper insights into understanding the structural and dynamic aspects of viral infection.
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Affiliation(s)
- Cristina Risco
- Cell Structure Laboratory, National Center for Biotechnology (CNB-CSIC), Madrid 28049, Spain;
| | | | - Laura Sanz-Sánchez
- Cell Structure Laboratory, National Center for Biotechnology (CNB-CSIC), Madrid 28049, Spain;
| | - Kedar Narayan
- Laboratory of Cell Biology, National Cancer Institute, Bethesda, Maryland 20892;
| | - Giovanna Grandinetti
- Laboratory of Cell Biology, National Cancer Institute, Bethesda, Maryland 20892;
| | - Sriram Subramaniam
- Laboratory of Cell Biology, National Cancer Institute, Bethesda, Maryland 20892;
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136
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Abstract
Cellular entry of retroviruses is the first critical stage of retroviral replication. Live cell imaging has been utilized to visualize the dynamics, localization, and kinetics of the viral fusion process. Here, we review the different methodologies used for live cell imaging and how the use of these techniques has better elucidated the viral entry process of avian sarcoma and leukosis virus (ASLV) and human immunodeficiency virus type 1 (HIV-1) as well as cell-to-cell transmission of retroviruses. Although some controversies remain, further development of these techniques will provide new insights into the process and dynamics of retroviral fusion in vivo.
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Affiliation(s)
- Amy E Hulme
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611;
| | - Thomas J Hope
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611;
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137
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Abstract
Enveloped viruses infect host cells by a membrane fusion reaction that takes place at the cell surface or in intracellular compartments following virus uptake. Fusion is mediated by the membrane interactions and conformational changes of specialized virus envelope proteins termed membrane fusion proteins. This article discusses the structures and refolding reactions of specific fusion proteins and the methods for their study and highlights outstanding questions in the field.
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Affiliation(s)
- Margaret Kielian
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461;
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138
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Anisotropic cell-to-cell spread of vaccinia virus on microgrooved substrate. Biomaterials 2014; 35:5049-55. [DOI: 10.1016/j.biomaterials.2014.03.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 03/11/2014] [Indexed: 12/11/2022]
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139
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Levraud JP, Palha N, Langevin C, Boudinot P. Through the looking glass: witnessing host-virus interplay in zebrafish. Trends Microbiol 2014; 22:490-7. [PMID: 24865811 DOI: 10.1016/j.tim.2014.04.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 04/27/2014] [Accepted: 04/30/2014] [Indexed: 12/21/2022]
Abstract
Host-pathogen interactions can be very complex at all scales; understanding organ- or organism-level events require in vivo approaches. Besides traditional host models such as mice, the zebrafish offers an attractive cocktail of optical accessibility and genetic tractability, blended with a vertebrate-type immunity, where innate responses can easily be separated from adaptive ones. Applied to viral infections, this model has revealed unexpected idiosyncrasies among organs, which we believe may apply to the human situation. We also argue that the dynamic analysis of virus spread and immune response in zebrafish make this model particularly well suited to the exploration of the concept of infection tolerance and resistance in relation to viral diseases.
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Affiliation(s)
- Jean-Pierre Levraud
- Institut Pasteur, Macrophages et Développement de l'Immunité, Paris, France; Centre National de la Recherche Scientifique (CNRS), URA 2578, Paris, France.
| | - Nuno Palha
- Institut Pasteur, Macrophages et Développement de l'Immunité, Paris, France; Centre National de la Recherche Scientifique (CNRS), URA 2578, Paris, France
| | - Christelle Langevin
- Institut National de la Recherche Agronomique (INRA), Virologie et Immunologie Moléculaire, Jouy-en-Josas, France
| | - Pierre Boudinot
- Institut National de la Recherche Agronomique (INRA), Virologie et Immunologie Moléculaire, Jouy-en-Josas, France
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140
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Xiao F, Fofana I, Heydmann L, Barth H, Soulier E, Habersetzer F, Doffoël M, Bukh J, Patel AH, Zeisel MB, Baumert TF. Hepatitis C virus cell-cell transmission and resistance to direct-acting antiviral agents. PLoS Pathog 2014; 10:e1004128. [PMID: 24830295 PMCID: PMC4022730 DOI: 10.1371/journal.ppat.1004128] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 04/02/2014] [Indexed: 12/12/2022] Open
Abstract
Hepatitis C virus (HCV) is transmitted between hepatocytes via classical cell entry but also uses direct cell-cell transfer to infect neighboring hepatocytes. Viral cell-cell transmission has been shown to play an important role in viral persistence allowing evasion from neutralizing antibodies. In contrast, the role of HCV cell-cell transmission for antiviral resistance is unknown. Aiming to address this question we investigated the phenotype of HCV strains exhibiting resistance to direct-acting antivirals (DAAs) in state-of-the-art model systems for cell-cell transmission and spread. Using HCV genotype 2 as a model virus, we show that cell-cell transmission is the main route of viral spread of DAA-resistant HCV. Cell-cell transmission of DAA-resistant viruses results in viral persistence and thus hampers viral eradication. We also show that blocking cell-cell transmission using host-targeting entry inhibitors (HTEIs) was highly effective in inhibiting viral dissemination of resistant genotype 2 viruses. Combining HTEIs with DAAs prevented antiviral resistance and led to rapid elimination of the virus in cell culture model. In conclusion, our work provides evidence that cell-cell transmission plays an important role in dissemination and maintenance of resistant variants in cell culture models. Blocking virus cell-cell transmission prevents emergence of drug resistance in persistent viral infection including resistance to HCV DAAs. In spite of the rapid development of antiviral agents, antiviral resistance remains a challenge for the treatment of viral infections including hepatitis B and C virus (HBV, HCV), human immunodeficiency virus (HIV) and influenza. Virus spreads from infected cells to surrounding uninfected host cells to develop infection through cell-free and cell-cell transmission routes. Understanding the spread of resistant virus is important for the development of novel antiviral strategies to prevent and treat antiviral resistance. Here, we characterize the spread of resistant viruses and its impact for emergence and prevention of resistance using HCV as a model system. Our results show that cell-cell transmission is the main transmission route for antiviral resistant HCV strains and is crucial for the maintenance of infection. Monoclonal antibodies or small molecules targeting HCV entry factors are effective in inhibiting the spread of resistant HCV in cell culture models and thus should be evaluated clinically for prevention and treatment of HCV resistance. Combination of inhibitors targeting viral entry and clinically used direct-acting antivirals (DAAs) prevents antiviral resistance and leads to viral eradication in cell culture models. Collectively, the investigation provides a new strategy for prevention of viral resistance to antiviral agents.
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Affiliation(s)
- Fei Xiao
- Inserm, U1110, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - Isabel Fofana
- Inserm, U1110, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - Laura Heydmann
- Inserm, U1110, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - Heidi Barth
- Inserm, U1110, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
- Laboratoire de Virologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Eric Soulier
- Inserm, U1110, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - François Habersetzer
- Inserm, U1110, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
- Pôle Hépato-digestif, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Michel Doffoël
- Inserm, U1110, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
- Pôle Hépato-digestif, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Jens Bukh
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases and Clinical Research Centre, Hvidovre Hospital and Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Arvind H. Patel
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Mirjam B. Zeisel
- Inserm, U1110, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - Thomas F. Baumert
- Inserm, U1110, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
- Pôle Hépato-digestif, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
- Gastrointestinal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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141
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142
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Rocha-Perugini V, Gordon-Alonso M, Sánchez-Madrid F. PIP2: choreographer of actin-adaptor proteins in the HIV-1 dance. Trends Microbiol 2014; 22:379-88. [PMID: 24768560 DOI: 10.1016/j.tim.2014.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/11/2014] [Accepted: 03/25/2014] [Indexed: 02/06/2023]
Abstract
The actin cytoskeleton plays a key role during the replication cycle of human immunodeficiency virus-1 (HIV-1). HIV-1 infection is affected by cellular proteins that influence the clustering of viral receptors or the subcortical actin cytoskeleton. Several of these actin-adaptor proteins are controlled by the second messenger phosphatidylinositol 4,5-biphosphate (PIP2), an important regulator of actin organization. PIP2 production is induced by HIV-1 attachment and facilitates viral infection. However, the importance of PIP2 in regulating cytoskeletal proteins and thus HIV-1 infection has been overlooked. This review examines recent reports describing the roles played by actin-adaptor proteins during HIV-1 infection of CD4+ T cells, highlighting the influence of the signaling lipid PIP2 in this process.
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Affiliation(s)
- Vera Rocha-Perugini
- Servicio de Inmunología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria de la Princesa, Madrid, Spain; Vascular Biology and Inflammation Department, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Mónica Gordon-Alonso
- Servicio de Inmunología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria de la Princesa, Madrid, Spain
| | - Francisco Sánchez-Madrid
- Servicio de Inmunología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria de la Princesa, Madrid, Spain; Vascular Biology and Inflammation Department, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain.
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143
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Agosto LM, Zhong P, Munro J, Mothes W. Highly active antiretroviral therapies are effective against HIV-1 cell-to-cell transmission. PLoS Pathog 2014; 10:e1003982. [PMID: 24586176 PMCID: PMC3937346 DOI: 10.1371/journal.ppat.1003982] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 01/22/2014] [Indexed: 11/30/2022] Open
Abstract
HIV-1 cell-to-cell transmission allows for 2-3 orders of magnitude more efficient viral spread than cell-free dissemination. The high local multiplicity of infection (MOI) observed at cell-cell contact sites may lower the efficacy of antiretroviral therapies (ART). Here we test the efficacy of commonly used antiretroviral inhibitors against cell-to-cell and cell-free HIV-1 transmission. We demonstrate that, while some nucleoside-analog reverse transcriptase inhibitors (NRTI) are less effective against HIV-1 cell-to-cell transmission, most non-nucleoside-analog reverse transcriptase inhibitors (NNRTI), entry inhibitors and protease inhibitors remain highly effective. Moreover, poor NRTIs become highly effective when applied in combinations explaining the effectiveness of ART in clinical settings. Investigating the underlying mechanism, we observe a strict correlation between the ability of individual drugs and combinations of drugs to interfere with HIV-1 cell-to-cell transmission, and their effectiveness against high viral MOIs. Our results suggest that the ability to suppress high viral MOI is a feature of effective ART regimens and this parameter should be considered when designing novel antiviral therapies.
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Affiliation(s)
- Luis M. Agosto
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Peng Zhong
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - James Munro
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, United States of America
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144
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Flanagan CA. Receptor Conformation and Constitutive Activity in CCR5 Chemokine Receptor Function and HIV Infection. ADVANCES IN PHARMACOLOGY 2014; 70:215-63. [DOI: 10.1016/b978-0-12-417197-8.00008-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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145
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Abstract
The innate immune system faces the difficult task of keeping a fine balance between sensitive detection of microbial presence and avoidance of autoimmunity. To this aim, key mechanisms of innate responses rely on isolation of pathogens in specialized subcellular compartments, or sensing of specific microbial patterns absent from the host. Efficient detection of foreign RNA in the cytosol requires an additional layer of complexity from the immune system. In this particular case, innate sensors should be able to distinguish self and non-self molecules that share several similar properties. In this review, we discuss this interplay between cytosolic pattern recognition receptors and the microbial RNA they detect. We describe how microbial RNAs gain access to the cytosol, which receptors they activate and counter-strategies developed by microorganisms to avoid this response.
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Affiliation(s)
- Nicolas Vabret
- Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai , New York, NY , USA
| | - J Magarian Blander
- Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai , New York, NY , USA ; Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai , New York, NY , USA
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146
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Murooka TT, Mempel TR. Intravital microscopy in BLT-humanized mice to study cellular dynamics in HIV infection. J Infect Dis 2013; 208 Suppl 2:S137-44. [PMID: 24151320 DOI: 10.1093/infdis/jit447] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Humanized mouse models have, over the past few years, seen dramatic improvements, including the colonization of both lymphoid and nonlymphoid tissues with all major immune cell lineages, the development of T cells with human major histocompatibility complex restriction, and the ability to mount functional adaptive immune responses to human pathogens, as documented in some instances. This has greatly increased the range of questions related to the biology of human immunodeficiency virus (HIV) infection that can be usefully addressed through experimental approaches utilizing small animal models. Among these approaches is in vivo imaging, and specifically multiphoton intravital microscopy (MP-IVM), which allows for the investigation of dynamic biological processes at cellular and subcellular resolution in the tissues of live animals. We have recently begun to use MP-IVM in lymph nodes of humanized mice in order to examine HIV infectious spread in vivo at the tissue and cellular level. Here, we provide a short perspective on the close link between the patterns of immune cell migration and the mechanisms of viral dissemination, and summarize the results of our initial studies.
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Affiliation(s)
- Thomas T Murooka
- The Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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147
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Earl LA, Lifson JD, Subramaniam S. Catching HIV 'in the act' with 3D electron microscopy. Trends Microbiol 2013; 21:397-404. [PMID: 23850373 PMCID: PMC3773172 DOI: 10.1016/j.tim.2013.06.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 06/12/2013] [Accepted: 06/13/2013] [Indexed: 11/25/2022]
Abstract
The development of a safe, effective vaccine to prevent HIV infection is a key step for controlling the disease on a global scale. However, many aspects of HIV biology make vaccine design problematic, including the sequence diversity and structural variability of the surface envelope glycoproteins and the poor accessibility of neutralization-sensitive epitopes on the virus. In this review, we discuss recent progress in understanding HIV in a structural context using emerging tools in 3D electron microscopy, and outline how some of these advances could be important for a better understanding of mechanisms of viral entry and for vaccine design.
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Affiliation(s)
- Lesley A Earl
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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148
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Thuy NT, Huy TQ, Nga PT, Morita K, Dunia I, Benedetti L. A new nidovirus (NamDinh virus NDiV): Its ultrastructural characterization in the C6/36 mosquito cell line. Virology 2013; 444:337-42. [PMID: 23891522 PMCID: PMC7111958 DOI: 10.1016/j.virol.2013.06.030] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 05/06/2013] [Accepted: 06/27/2013] [Indexed: 11/18/2022]
Abstract
We describe the ultrastructure of the NamDinh virus (NDiV), a new member of the order Nidovirales grown in the C6/36 mosquito cell line. Uninfected and NDiV-infected cells were investigated by electron microscopy 24-48 h after infection. The results show that the viral nucleocapsid-like particles form clusters concentrated in the vacuoles, the endoplasmic reticulum, and are scattered in the cytoplasm. Mature virions of NDiV were released as budding particles on the cell surface where viral components appear to lie beneath and along the plasma membrane. Free homogeneous virus particles were obtained by ultracentrifugation on sucrose gradients of culture fluids. The size of the round-shaped particles with a complete internal structure was 80 nm in diameter. This is the first study to provide information on the morphogenesis and ultrastructure of the first insect nidovirus NDiV, a missing evolutionary link in the emergence of the viruses with the largest RNA genomes.
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Affiliation(s)
- Nguyen Thanh Thuy
- National Institute of Hygiene and Epidemiology, 1 Yersin Street, Hai Ba Trung District, Hanoi, Viet Nam.
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Clustering and mobility of HIV-1 Env at viral assembly sites predict its propensity to induce cell-cell fusion. J Virol 2013; 87:7516-25. [PMID: 23637402 DOI: 10.1128/jvi.00790-13] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
HIV-1 Env mediates virus attachment to and fusion with target cell membranes, and yet, while Env is still situated at the plasma membrane of the producer cell and before its incorporation into newly formed particles, Env already interacts with the viral receptor CD4 on target cells, thus enabling the formation of transient cell contacts that facilitate the transmission of viral particles. During this first encounter with the receptor, Env must not induce membrane fusion, as this would prevent the producer cell and the target cell from separating upon virus transmission, but how Env's fusion activity is controlled remains unclear. To gain a better understanding of the Env regulation that precedes viral transmission, we examined the nanoscale organization of Env at the surface of producer cells. Utilizing superresolution microscopy (stochastic optical reconstruction microscopy [STORM]) and fluorescence recovery after photobleaching (FRAP), we quantitatively assessed the clustering and dynamics of Env upon its arrival at the plasma membrane. We found that Gag assembly induced the aggregation of small Env clusters into larger domains and that these domains were completely immobile. Truncation of the cytoplasmic tail (CT) of Env abrogated Gag's ability to induce Env clustering and restored Env mobility at assembly sites, both of which correlated with increased Env-induced fusion of infected and uninfected cells. Hence, while Env trapping by Gag secures Env incorporation into viral particles, Env clustering and its sequestration at assembly sites likely also leads to the repression of its fusion function, and thus, by preventing the formation of syncytia, Gag helps to secure efficient transfer of viral particles to target cells.
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