scholarly journals Influence of different glycoproteins and of the virion core on SERINC5 antiviral activity

2019 ◽  
Author(s):  
William E. Diehl ◽  
Mehmet H. Guney ◽  
Pyae Phyo Kyawe ◽  
Judith M. White ◽  
Massimo Pizzato ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Antiviral Activity ◽  
Viral Entry ◽  
Ebola Virus ◽  
Endogenous Retrovirus ◽  
Marburg Virus ◽  
Human Endogenous Retrovirus ◽  
Target Cells ◽  
Viral Glycoprotein ◽  
Hiv 1

ABSTRACTHost plasma membrane protein SERINC5 is incorporated into budding retrovirus particles where it blocks subsequent entry into susceptible target cells. Three accessory proteins encoded by diverse retroviruses, HIV-1 Nef, EIAV S2, and MLV Glycogag, each independently disrupt SERINC5 antiviral activity, by redirecting SERINC5 from the site of virion assembly on the plasma membrane to an internal RAB7+ endosomal compartment. Pseudotyping retroviruses with particular glycoproteins, e.g., the vesicular stomatitis glycoprotein (VSV G), renders the infectivity of particles resistant to inhibition by virion-associated SERINC5. To better understand viral determinants for SERINC5-sensitivity, the effect of SERINC5 was assessed using HIV-1, MLV, and M-PMV virion cores, pseudotyped with glycoproteins from Arenavirus, Coronavirus, Filovirus, Rhabdovirus, Paramyxovirus, and Orthomyxovirus genera. Infectivity of particles, pseudotyped with HIV-1, amphotropic-MLV, or influenza virus glycoproteins, was decreased by SERINC5, whether the core was provided by HIV-1, MLV, or M-PMV. Particles generated by all three cores, and pseudotyped with glycoproteins from either avian leukosis virus-A, human endogenous retrovirus K (HERV-K), ecotropic-MLV, HTLV-1, Measles morbillivirus, lymphocytic choriomeningitis mammarenavirus (LCMV), Marburg virus, Ebola virus, severe acute respiratory syndrome-related coronavirus (SARS-CoV), or VSV, were insensitive to SERINC5. In contrast, particles pseudotyped with M-PMV, RD114, or rabies virus (RABV) glycoproteins were sensitive to SERINC5, but only with particular retroviral cores. Resistance to SERINC5 by particular glycoproteins did not correlate with reduced SERINC5 incorporation into particles or with the route of viral entry. These findings indicate that some non-retroviruses may be sensitive to SERINC5 and that, in addition to the viral glycoprotein, the retroviral core influences sensitivity to SERINC5.IMPORTANCEThe importance of SERINC5 for inhibition of retroviruses is underscored by convergent evolution among three non-monophyletic retroviruses, each of which encodes a structurally unrelated SERINC5 inhibitor. One of these retroviruses causes tumors in mice, a second anemia in horses, and a third causes AIDS. SERINC5 is incorporated into retrovirus particles where it blocks entry into target cells, via a mechanism that is dependent on the viral glycoprotein. Here we demonstrate that retroviruses pseudotyped with glycoproteins from several non-retroviruses are also inhibited by SERINC5, suggesting that enveloped viruses other than retroviruses may also be inhibited by SERINC5. Additionally, we found that sensitivity to SERINC5 is determined by the retrovirus core, as well as by the glycoprotein. By better understanding how SERINC5 inhibits viruses we hope to extend fundamental understanding of virus replication and of the native role of SERINC5 in cells, and perhaps to advance the development of new antiviral strategies.

scholarly journals Inhibition of Ebola Virus Entry by a C-peptide Targeted to Endosomes

2011 ◽  
Vol 286 (18) ◽  
pp. 15854-15861 ◽  
Author(s):  
Emily Happy Miller ◽  
Joseph S. Harrison ◽  
Sheli R. Radoshitzky ◽  
Chelsea D. Higgins ◽  
Xiaoli Chi ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Viral Entry ◽  
Ebola Virus ◽  
Hemorrhagic Fever ◽  
Marburg Virus ◽  
Viral Envelope ◽  
Heptad Repeat ◽  
Fusion Event ◽  
C Peptide ◽  
Hiv 1

Ebola virus (EboV) and Marburg virus (MarV) (filoviruses) are the causative agents of severe hemorrhagic fever. Infection begins with uptake of particles into cellular endosomes, where the viral envelope glycoprotein (GP) catalyzes fusion between the viral and host cell membranes. This fusion event is thought to involve conformational rearrangements of the transmembrane subunit (GP2) of the envelope spike that ultimately result in formation of a six-helix bundle by the N- and C-terminal heptad repeat (NHR and CHR, respectively) regions of GP2. Infection by other viruses employing similar viral entry mechanisms (such as HIV-1 and severe acute respiratory syndrome coronavirus) can be inhibited with synthetic peptides corresponding to the native CHR sequence (“C-peptides”). However, previously reported EboV C-peptides have shown weak or insignificant antiviral activity. To determine whether the activity of a C-peptide could be improved by increasing its intracellular concentration, we prepared an EboV C-peptide conjugated to the arginine-rich sequence from HIV-1 Tat, which is known to accumulate in endosomes. We found that this peptide specifically inhibited viral entry mediated by filovirus GP proteins and infection by authentic filoviruses. We determined that antiviral activity was dependent on both the Tat sequence and the native EboV CHR sequence. Mechanistic studies suggested that the peptide acts by blocking a membrane fusion intermediate.

scholarly journals Comprehensive Analysis of Ebola Virus GP1 in Viral Entry

2005 ◽  
Vol 79 (8) ◽  
pp. 4793-4805 ◽  
Author(s):  
Balaji Manicassamy ◽  
Jizhen Wang ◽  
Haiqing Jiang ◽  
Lijun Rong
Keyword(s):  
Viral Entry ◽  
Ebola Virus ◽  
Binding Pocket ◽  
Marburg Virus ◽  
Pseudotyped Virus ◽  
Viral Glycoprotein ◽  
Functional Roles ◽  
Critical Residues ◽  
And Function ◽  
Expression Processing

ABSTRACT Ebola virus infection is initiated by interactions between the viral glycoprotein GP1 and its cognate receptor(s), but little is known about the structure and function of GP1 in viral entry, partly due to the concern about safety when working with the live Ebola virus and the difficulty of manipulating the RNA genome of Ebola virus. In this study, we have used a human immunodeficiency virus-based pseudotyped virus as a surrogate system to dissect the role of Ebola virus GP1 in viral entry. Analysis of more than 100 deletion and amino acid substitution mutants of GP1 with respect to protein expression, processing, viral incorporation, and viral entry has allowed us to map the region of GP1 responsible for viral entry to the N-terminal 150 residues. Furthermore, six amino acids in this region have been identified as critical residues for early events in Ebola virus entry, and among these, three are clustered and are implicated as part of a potential receptor-binding pocket. In addition, substitutions of some 30 residues in GP1 are shown to adversely affect GP1 expression, processing, and viral incorporation, suggesting that these residues are involved in the proper folding and/or overall conformation of GP. Sequence comparison of the GP1 proteins suggests that the majority of the critical residues for GP folding and viral entry identified in Ebola virus GP1 are conserved in Marburg virus. These results provide information for elucidating the structural and functional roles of the filoviral glycoproteins and for developing potential therapeutics to block viral entry.

scholarly journals Ebola virus triggers receptor tyrosine kinase-dependent signaling to promote the delivery of viral particles to entry-conducive intracellular compartments

2021 ◽  
Vol 17 (1) ◽  
pp. e1009275
Author(s):  
Corina M. Stewart ◽  
Alexandra Phan ◽  
Yuxia Bo ◽  
Nicholas D. LeBlond ◽  
Tyler K. T. Smith ◽  
...  
Keyword(s):  
Growth Factor ◽  
Tyrosine Kinase ◽  
Viral Entry ◽  
Receptor Tyrosine Kinase ◽  
Ebola Virus ◽  
Marburg Virus ◽  
Host Protein ◽  
Signaling Cascades ◽  
Viral Glycoprotein ◽  
Viral Particles

Filoviruses, such as the Ebola virus (EBOV) and Marburg virus (MARV), are causative agents of sporadic outbreaks of hemorrhagic fevers in humans. To infect cells, filoviruses are internalized via macropinocytosis and traffic through the endosomal pathway where host cathepsin-dependent cleavage of the viral glycoproteins occurs. Subsequently, the cleaved viral glycoprotein interacts with the late endosome/lysosome resident host protein, Niemann-Pick C1 (NPC1). This interaction is hypothesized to trigger viral and host membrane fusion, which results in the delivery of the viral genome into the cytoplasm and subsequent initiation of replication. Some studies suggest that EBOV viral particles activate signaling cascades and host-trafficking factors to promote their localization with host factors that are essential for entry. However, the mechanism through which these activating signals are initiated remains unknown. By screening a kinase inhibitor library, we found that receptor tyrosine kinase inhibitors potently block EBOV and MARV GP-dependent viral entry. Inhibitors of epidermal growth factor receptor (EGFR), tyrosine protein kinase Met (c-Met), and the insulin receptor (InsR)/insulin like growth factor 1 receptor (IGF1R) blocked filoviral GP-mediated entry and prevented growth of replicative EBOV in Vero cells. Furthermore, inhibitors of c-Met and InsR/IGF1R also blocked viral entry in macrophages, the primary targets of EBOV infection. Interestingly, while the c-Met and InsR/IGF1R inhibitors interfered with EBOV trafficking to NPC1, virus delivery to the receptor was not impaired in the presence of the EGFR inhibitor. Instead, we observed that the NPC1 positive compartments were phenotypically altered and rendered incompetent to permit viral entry. Despite their different mechanisms of action, all three RTK inhibitors tested inhibited virus-induced Akt activation, providing a possible explanation for how EBOV may activate signaling pathways during entry. In sum, these studies strongly suggest that receptor tyrosine kinases initiate signaling cascades essential for efficient post-internalization entry steps.

scholarly journals SARS-CoV-2 Cellular Infection and Therapeutic Opportunities: Lessons Learned from Ebola Virus

Membranes ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 64
Author(s):  
Jordana Muñoz-Basagoiti ◽  
Daniel Perez-Zsolt ◽  
Jorge Carrillo ◽  
Julià Blanco ◽  
Bonaventura Clotet ◽  
...  
Keyword(s):  
Viral Entry ◽  
Ebola Virus ◽  
Lessons Learned ◽  
Productive Infection ◽  
Target Cells ◽  
Emerging Viruses ◽  
Highly Pathogenic ◽  
Life Threatening ◽  
Pathogenic Viruses ◽  
Cellular Machinery

Viruses rely on the cellular machinery to replicate and propagate within newly infected individuals. Thus, viral entry into the host cell sets up the stage for productive infection and disease progression. Different viruses exploit distinct cellular receptors for viral entry; however, numerous viral internalization mechanisms are shared by very diverse viral families. Such is the case of Ebola virus (EBOV), which belongs to the filoviridae family, and the recently emerged coronavirus SARS-CoV-2. These two highly pathogenic viruses can exploit very similar endocytic routes to productively infect target cells. This convergence has sped up the experimental assessment of clinical therapies against SARS-CoV-2 previously found to be effective for EBOV, and facilitated their expedited clinical testing. Here we review how the viral entry processes and subsequent replication and egress strategies of EBOV and SARS-CoV-2 can overlap, and how our previous knowledge on antivirals, antibodies, and vaccines against EBOV has boosted the search for effective countermeasures against the new coronavirus. As preparedness is key to contain forthcoming pandemics, lessons learned over the years by combating life-threatening viruses should help us to quickly deploy effective tools against novel emerging viruses.

scholarly journals Human Endogenous Retrovirus Expression Is Inversely Associated with Chronic Immune Activation in HIV-1 Infection

PLoS ONE ◽  
2012 ◽  
Vol 7 (8) ◽  
pp. e41021 ◽  
Author(s):  
Christopher E. Ormsby ◽  
Devi SenGupta ◽  
Ravi Tandon ◽  
Steven G. Deeks ◽  
Jeffrey N. Martin ◽  
...  
Keyword(s):  
Immune Activation ◽  
Endogenous Retrovirus ◽  
Human Endogenous Retrovirus ◽  
Chronic Immune Activation ◽  
Hiv 1

scholarly journals HIV-1 requires Arf6-mediated membrane dynamics to efficiently enter and infect T lymphocytes

2011 ◽  
Vol 22 (8) ◽  
pp. 1148-1166 ◽  
Author(s):  
Laura García-Expósito ◽  
Jonathan Barroso-González ◽  
Isabel Puigdomènech ◽  
José-David Machado ◽  
Julià Blanco ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
T Lymphocytes ◽  
Viral Entry ◽  
Membrane Trafficking ◽  
Membrane Dynamics ◽  
Viral Fusion ◽  
Viral Attachment ◽  
Immunodeficiency Virus ◽  
Vesicular Stomatitis ◽  
Hiv 1

As the initial barrier to viral entry, the plasma membrane along with the membrane trafficking machinery and cytoskeleton are of fundamental importance in the viral cycle. However, little is known about the contribution of plasma membrane dynamics during early human immunodeficiency virus type 1 (HIV-1) infection. Considering that ADP ribosylation factor 6 (Arf6) regulates cellular invasion via several microorganisms by coordinating membrane trafficking, our aim was to study the function of Arf6-mediated membrane dynamics on HIV-1 entry and infection of T lymphocytes. We observed that an alteration of the Arf6–guanosine 5′-diphosphate/guanosine 5′-triphosphate (GTP/GDP) cycle, by GDP-bound or GTP-bound inactive mutants or by specific Arf6 silencing, inhibited HIV-1 envelope–induced membrane fusion, entry, and infection of T lymphocytes and permissive cells, regardless of viral tropism. Furthermore, cell-to-cell HIV-1 transmission of primary human CD4+T lymphocytes was inhibited by Arf6 knockdown. Total internal reflection fluorescence microscopy showed that Arf6 mutants provoked the accumulation of phosphatidylinositol-(4,5)-biphosphate–associated structures on the plasma membrane of permissive cells, without affecting CD4-viral attachment but impeding CD4-dependent HIV-1 entry. Arf6 silencing or its mutants did not affect fusion, entry, and infection of vesicular stomatitis virus G–pseudotyped viruses or ligand-induced CXCR4 or CCR5 endocytosis, both clathrin-dependent processes. Therefore we propose that efficient early HIV-1 infection of CD4+T lymphocytes requires Arf6-coordinated plasma membrane dynamics that promote viral fusion and entry.

scholarly journals Membrane Binding and Subcellular Localization of Retroviral Gag Proteins Are Differentially Regulated by MA Interactions with Phosphatidylinositol-(4,5)-Bisphosphate and RNA

mBio ◽  
2014 ◽  
Vol 5 (6) ◽  
Author(s):  
Jingga Inlora ◽  
David R. Collins ◽  
Marc E. Trubin ◽  
Ji Yeon J. Chung ◽  
Akira Ono
Keyword(s):  
Virus Assembly ◽  
Membrane Binding ◽  
Endogenous Retrovirus ◽  
Single Amino Acid ◽  
Human Endogenous Retrovirus ◽  
Structural Protein ◽  
Acidic Phospholipid ◽  
Specific Localization ◽  
Hiv 1

ABSTRACTThe matrix (MA) domain of HIV-1 mediates proper Gag localization and membrane binding via interaction with a plasma-membrane (PM)-specific acidic phospholipid, phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2]. HIV-1 MA also interacts with RNA, which prevents Gag from binding to membranes containing phosphatidylserine, a prevalent cellular acidic phospholipid. These results suggest that the MA-bound RNA promotes PM-specific localization of HIV-1 Gag by blocking nonspecific interactions with cellular membranes that do not contain PI(4,5)P2. To examine whether PI(4,5)P2dependence and RNA-mediated inhibition collectively determine MA phenotypes across a broad range of retroviruses and elucidate the significance of their interrelationships, we compared a panel of Gag-leucine zipper constructs (GagLZ) containing MA of different retroviruses. We found thatin vitromembrane binding of GagLZ via HIV-1 MA and Rous sarcoma virus (RSV) MA is both PI(4,5)P2dependent and susceptible to RNA-mediated inhibition. The PM-specific localization and virus-like particle (VLP) release of these GagLZ proteins are severely impaired by overexpression of a PI(4,5)P2-depleting enzyme, polyphosphoinositide 5-phosphatase IV (5ptaseIV). In contrast, membrane binding of GagLZ constructs that contain human T-lymphotropic virus type 1 (HTLV-1) MA, murine leukemia virus (MLV) MA, and human endogenous retrovirus K (HERV-K) MA is PI(4,5)P2independent and not blocked by RNA. The PM localization and VLP release of these GagLZ chimeras were much less sensitive to 5ptaseIV expression. Notably, single amino acid substitutions that confer a large basic patch rendered HTLV-1 MA susceptible to the RNA-mediated block, suggesting that RNA readily blocks MA containing a large basic patch, such as HIV-1 and RSV MA. Further analyses of these MA mutants suggest a possibility that HIV-1 and RSV MA acquired PI(4,5)P2dependence to alleviate the membrane binding block imposed by RNA.IMPORTANCEMA basic residues in the HIV-1 structural protein Gag interact with phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2] and RNA. RNA inhibits HIV-1 MA binding to non-PI(4,5)P2acidic lipids. This inhibition may promote PM specificity of Gag membrane binding, an early essential step in virus assembly. However, whether and how relationships between these interactions have developed among retroviruses are poorly understood. In this study, by comparing diverse retroviral MA domains, we elucidated a strong correlation among PI(4,5)P2dependence, susceptibility to RNA-mediated inhibition, and cellular behaviors of Gag. Mutagenesis analyses suggest that a large basic patch on MA is sufficient to confer susceptibility to RNA-mediated inhibition but not for PI(4,5)P2-dependent membrane binding. Our findings highlight RNA’s role as a general blocker of large basic patches and suggest a possibility that some retroviruses, including HIV-1, have evolved to bind PI(4,5)P2, while others have adopted smaller basic patches on their MA domains, to overcome the RNA-mediated restriction of membrane binding.

scholarly journals PSGL-1 restricts HIV-1 infectivity by blocking virus particle attachment to target cells

2020 ◽  
Vol 117 (17) ◽  
pp. 9537-9545 ◽  
Author(s):  
Yajing Fu ◽  
Sijia He ◽  
Abdul A. Waheed ◽  
Deemah Dabbagh ◽  
Zheng Zhou ◽  
...  
Keyword(s):  
Virus Particle ◽  
Influenza A ◽  
Leukemia Virus ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Target Cells ◽  
Viral Glycoprotein ◽  
Selectin Binding ◽  
Anti Hiv ◽  
Hiv 1

P-selectin glycoprotein ligand-1 (PSGL-1) is a dimeric, mucin-like, 120-kDa glycoprotein that binds to P-, E-, and L-selectins. PSGL-1 is expressed primarily on the surface of lymphoid and myeloid cells and is up-regulated during inflammation to mediate leukocyte tethering and rolling on the surface of endothelium for migration into inflamed tissues. Although it has been reported that PSGL-1 expression inhibits HIV-1 replication, the mechanism of PSGL-1–mediated anti-HIV activity remains to be elucidated. Here we report that PSGL-1 in virions blocks the infectivity of HIV-1 particles by preventing the binding of particles to target cells. This inhibitory activity is independent of the viral glycoprotein present on the virus particle; the binding of particles bearing the HIV-1 envelope glycoprotein or vesicular stomatitis virus G glycoprotein or even lacking a viral glycoprotein is impaired by PSGL-1. Mapping studies show that the extracellular N-terminal domain of PSGL-1 is necessary for its anti–HIV-1 activity, and that the PSGL-1 cytoplasmic tail contributes to inhibition. In addition, we demonstrate that the PSGL-1–related monomeric E-selectin–binding glycoprotein CD43 also effectively blocks HIV-1 infectivity. HIV-1 infection, or expression of either Vpu or Nef, down-regulates PSGL-1 from the cell surface; expression of Vpu appears to be primarily responsible for enabling the virus to partially escape PSGL-1–mediated restriction. Finally, we show that PSGL-1 inhibits the infectivity of other viruses, such as murine leukemia virus and influenza A virus. These findings demonstrate that PSGL-1 is a broad-spectrum antiviral host factor with a unique mechanism of action.

scholarly journals Extracellular vesicles from symbiotic vaginal lactobacilli inhibit HIV-1 infection of human tissues

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Rogers A. Ñahui Palomino ◽  
Christophe Vanpouille ◽  
Luca Laghi ◽  
Carola Parolin ◽  
Kamran Melikov ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Viral Entry ◽  
Ex Vivo ◽  
Target Cells ◽  
Isolated Cells ◽  
Viral Attachment ◽  
Vaginal Lactobacilli ◽  
Male To Female ◽  
Hiv 1

AbstractThe vaginal microbiota, dominated by Lactobacillus spp., plays a key role in preventing HIV-1 transmission. Here, we investigate whether the anti-HIV effect of lactobacilli is mediated by extracellular vesicles (EVs) released by these bacteria. Human cervico-vaginal and tonsillar tissues ex vivo, and cell lines were infected with HIV-1 and treated with EVs released by lactobacilli isolated from vaginas of healthy women. EVs released by L. crispatus BC3 and L. gasseri BC12 protect tissues ex vivo and isolated cells from HIV-1 infection. This protection is associated with a decrease of viral attachment to target cells and viral entry due to diminished exposure of Env that mediates virus-cell interactions. Inhibition of HIV-1 infection is associated with the presence in EVs of several proteins and metabolites. Our findings demonstrate that the protective effect of Lactobacillus against HIV-1 is, in part, mediated by EVs released by these symbiotic bacteria. If confirmed in vivo, this finding may lead to new strategies to prevent male-to-female sexual HIV-1 transmission.

scholarly journals The HERV-K Human Endogenous Retrovirus Envelope Protein Antagonizes Tetherin Antiviral Activity

2014 ◽  
Vol 88 (23) ◽  
pp. 13626-13637 ◽  
Author(s):  
C. Lemaitre ◽  
F. Harper ◽  
G. Pierron ◽  
T. Heidmann ◽  
M. Dewannieux
Keyword(s):  
Antiviral Activity ◽  
Envelope Protein ◽  
Endogenous Retrovirus ◽  
Human Endogenous Retrovirus
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