scholarly journals RAGE inhibits human respiratory syncytial virus syncytium formation by interfering with F-protein function

2013 ◽  
Vol 94 (8) ◽  
pp. 1691-1700 ◽  
Author(s):  
Jane Tian ◽  
Kelly Huang ◽  
Subramaniam Krishnan ◽  
Catherine Svabek ◽  
Daniel C. Rowe ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Epithelial Cells ◽  
Syncytium Formation ◽  
Human Respiratory Syncytial Virus ◽  
Host Cells ◽  
Type I ◽  
F Protein ◽  
Viral Spread ◽  
Infected Cells ◽  
Syncytial Virus

Human respiratory syncytial virus (RSV) is a major cause of severe lower respiratory tract infection. Infection is critically dependent on the RSV fusion (F) protein, which mediates fusion between the viral envelope and airway epithelial cells. The F protein is also expressed on infected cells and is responsible for fusion of infected cells with adjacent cells, resulting in the formation of multinucleate syncytia. The receptor for advanced glycation end products (RAGE) is a pattern-recognition receptor that is constitutively highly expressed by type I alveolar epithelial cells. Here, we report that RAGE protected HEK cells from RSV-induced cell death and reduced viral titres in vitro. RAGE appeared to interact directly with the F protein, but, rather than inhibiting RSV entry into host cells, virus replication and budding, membrane-expressed RAGE or soluble RAGE blocked F-protein-mediated syncytium formation and sloughing. These data indicate that RAGE may contribute to protecting the lower airways from RSV by inhibiting the formation of syncytia, viral spread, epithelial damage and airway obstruction.

scholarly journals N-Glycans of F Protein Differentially Affect Fusion Activity of Human Respiratory Syncytial Virus

2001 ◽  
Vol 75 (10) ◽  
pp. 4744-4751 ◽  
Author(s):  
Gert Zimmer ◽  
Ina Trotz ◽  
Georg Herrler
Keyword(s):  
Respiratory Syncytial Virus ◽  
Cell Surface ◽  
Fusion Protein ◽  
Syncytium Formation ◽  
Human Respiratory Syncytial Virus ◽  
Fusion Activity ◽  
Triple Mutant ◽  
Activity Increase ◽  
F Protein ◽  
Syncytial Virus

ABSTRACT The human respiratory syncytial virus (Long strain) fusion protein contains six potential N-glycosylation sites: N27, N70, N116, N120, N126, and N500. Site-directed mutagenesis of these positions revealed that the mature fusion protein contains three N-linked oligosaccharides, attached to N27, N70, and N500. By introducing these mutations into the F gene in different combinations, four more mutants were generated. All mutants, including a triple mutant devoid of any N-linked oligosaccharide, were efficiently transported to the plasma membrane, as determined by flow cytometry and cell surface biotinylation. None of the glycosylation mutations interfered with proteolytic activation of the fusion protein. Despite similar levels of cell surface expression, the glycosylation mutants affected fusion activity in different ways. While the N27Q mutation did not have an effect on syncytium formation, loss of the N70-glycan caused a fusion activity increase of 40%. Elimination of both N-glycans (N27/70Q mutant) reduced the fusion activity by about 50%. A more pronounced reduction of the fusion activity of about 90% was observed with the mutants N500Q, N27/500Q, and N70/500Q. Almost no fusion activity was detected with the triple mutant N27/70/500Q. These data indicate that N-glycosylation of the F2 subunit at N27 and N70 is of minor importance for the fusion activity of the F protein. The single N-glycan of the F1 subunit attached to N500, however, is required for efficient syncytium formation.

scholarly journals Characterization of Pre-F-GCN4t, a Modified Human Respiratory Syncytial Virus Fusion Protein Stabilized in a Noncleaved Prefusion Conformation

2017 ◽  
Vol 91 (13) ◽  
Author(s):  
Normand Blais ◽  
Martin Gagné ◽  
Yoshitomo Hamuro ◽  
Patrick Rheault ◽  
Martine Boyer ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Antibody Response ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Human Respiratory Syncytial Virus ◽  
Vaccine Antigen ◽  
Significant Advance ◽  
F Protein ◽  
Syncytial Virus

ABSTRACT The human respiratory syncytial virus (hRSV) fusion (F) protein is considered a major target of the neutralizing antibody response to hRSV. This glycoprotein undergoes a major structural shift from the prefusion (pre-F) to the postfusion (post-F) state at the time of virus-host cell membrane fusion. Recent evidences suggest that the pre-F state is a superior target for neutralizing antibodies compared to the post-F state. Therefore, for vaccine purposes, we have designed and characterized a recombinant hRSV F protein, called Pre-F-GCN4t, stabilized in a pre-F conformation. To show that Pre-F-GCN4t does not switch to a post-F conformation, it was compared with a recombinant post-F molecule, called Post-F-XC. Pre-F-GCN4t was glycosylated and trimeric and displayed a conformational stability different from that of Post-F-XC, as shown by chemical denaturation. Electron microscopy analysis suggested that Pre-F-GCN4t adopts a lollipop-like structure. In contrast, Post-F-XC had a typical elongated conical shape. Hydrogen/deuterium exchange mass spectrometry demonstrated that the two molecules had common rigid folding core and dynamic regions and provided structural insight for their biophysical and biochemical properties and reactivity. Pre-F-GCN4t was shown to deplete hRSV-neutralizing antibodies from human serum more efficiently than Post-F-XC. Importantly, Pre-F-GCN4t was also shown to bind D25, a highly potent monoclonal antibody specific for the pre-F conformation. In conclusion, this construct presents several pre-F characteristics, does not switch to the post-F conformation, and presents antigenic features required for a protective neutralizing antibody response. Therefore, Pre-F-GCN4t can be considered a promising candidate vaccine antigen. IMPORTANCE Human respiratory syncytial virus (RSV) is a global leading cause of infant mortality and adult morbidity. The development of a safe and efficacious RSV vaccine remains an important goal. The RSV class I fusion (F) glycoprotein is considered one of the most promising vaccine candidates, and recent evidences suggest that the prefusion (pre-F) state is a superior target for neutralizing antibodies. Our study presents the physicochemical characterization of Pre-F-GCN4t, a molecule designed to be stabilized in the pre-F conformation. To confirm its pre-F conformation, Pre-F-GCN4t was analyzed in parallel with Post-F-XC, a molecule in the post-F conformation. Our results show that Pre-F-GCN4t presents characteristics of a stabilized pre-F conformation and support its use as an RSV vaccine antigen. Such an antigen may represent a significant advance in the development of an RSV vaccine.

scholarly journals CX3CR1 Engagement by Respiratory Syncytial Virus Leads to Induction of Nucleolin and Dysregulation of Cilia-related Genes

2020 ◽  
Author(s):  
Christopher S. Anderson ◽  
Tatiana Chirkova ◽  
Christopher G. Slaunwhite ◽  
Xing Qiu ◽  
Edward E. Walsh ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Epithelial Cells ◽  
G Protein ◽  
Infected Individual ◽  
The Elderly ◽  
Lung Epithelial Cells ◽  
Host Cells ◽  
Ciliated Cells ◽  
Transcriptional Changes ◽  
Syncytial Virus

AbstractRespiratory syncytial virus (RSV) contains a conserved CX3C motif on the ectodomain of the G-protein. The motif has been indicated as facilitating attachment of the virus to the host initiating infection via the human CX3CR1 receptor. The natural CX3CR1 ligand, CX3CL1, has been shown to induce signaling pathways resulting in transcriptional changes in the host cells. We hypothesize that binding of RSV to CX3CR1 via CX3C leads to transcriptional changes in host epithelial cells. Using transcriptomic analysis, the effect of CX3CR1 engagement by RSV was investigated. Normal human bronchial epithelial (NHBE) cells were infected with RSV virus containing either wildtype G-protein, or a mutant virus containing a CX4C mutation in the G-protein. RNA sequencing was performed on mock and 4-days-post-infected cultures. NHBE cultures were also treated with purified recombinant wild-type A2 G-protein. Here we report that RSV infection resulted in significant changes in the levels 766 transcripts. Many nuclear associated proteins were upregulated in the WT group, including Nucleolin. Alternatively, cilia-associated genes, including CC2D2A and CFAP221 (PCDP1), were downregulated. The addition of recombinant G-protein to the culture lead to the suppression of cilia-related genes while also inducing Nucleolin. Mutation of the CX3C motif (CX4C) reversed these effects on transcription decreasing nucleolin induction and lessening the suppression of cilia-related transcripts in culture. Furthermore, immunohistochemical staining demonstrated decreases in in ciliated cells and altered morphology. Therefore, it appears that engagement of CX3CR1 leads to induction of genes necessary for RSV entry as well as dysregulation of genes associated with cilia function.ImportanceRespiratory Syncytial Virus (RSV) has an enormous impact on infants and the elderly including increased fatality rates and potential for causing lifelong lung problems. Humans become infected with RSV through the inhalation of viral particles exhaled from an infected individual. These virus particles contain specific proteins that the virus uses to attach to human ciliated lung epithelial cells, initiating infection. Two viral proteins, G-protein and F-protein, have been shown to bind to human CX3CR1and Nucleolin, respectively. Here we show that the G-protein induces Nucleolin and suppresses gene transcripts specific to ciliated cells. Furthermore, we show that mutation of the CX3C-motif on the G-protein, CX4C, reverses these transcriptional changes.

scholarly journals Differential Responses by Human Respiratory Epithelial Cell Lines to Respiratory Syncytial Virus Reflect Distinct Patterns of Infection Control

2018 ◽  
Vol 92 (15) ◽  
Author(s):  
Philippa Hillyer ◽  
Rachel Shepard ◽  
Megan Uehling ◽  
Mina Krenz ◽  
Faruk Sheikh ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Cell Lines ◽  
A549 Cells ◽  
Type I ◽  
Epithelial Cell Lines ◽  
Rsv Infection ◽  
Syncytial Virus ◽  
Respiratory Epithelial

ABSTRACT Respiratory syncytial virus (RSV) infects small foci of respiratory epithelial cells via infected droplets. Infection induces expression of type I and III interferons (IFNs) and proinflammatory cytokines, the balance of which may restrict viral replication and affect disease severity. We explored this balance by infecting two respiratory epithelial cell lines with low doses of recombinant RSV expressing green fluorescent protein (rgRSV). A549 cells were highly permissive, whereas BEAS-2B cells restricted infection to individual cells or small foci. After infection, A549 cells expressed higher levels of IFN-β-, IFN-λ-, and NF-κB-inducible proinflammatory cytokines. In contrast, BEAS-2B cells expressed higher levels of antiviral interferon-stimulated genes, pattern recognition receptors, and other signaling intermediaries constitutively and after infection. Transcriptome analysis revealed that constitutive expression of antiviral and proinflammatory genes predicted responses by each cell line. These two cell lines provide a model for elucidating critical mediators of local control of viral infection in respiratory epithelial cells. IMPORTANCE Airway epithelium is both the primary target of and the first defense against respiratory syncytial virus (RSV). Whether RSV replicates and spreads to adjacent epithelial cells depends on the quality of their innate immune responses. A549 and BEAS-2B are alveolar and bronchial epithelial cell lines, respectively, that are often used to study RSV infection. We show that A549 cells are permissive to RSV infection and express genes characteristic of a proinflammatory response. In contrast, BEAS-2B cells restrict infection and express genes characteristic of an antiviral response associated with expression of type I and III interferons. Transcriptome analysis of constitutive gene expression revealed patterns that may predict the response of each cell line to infection. This study suggests that restrictive and permissive cell lines may provide a model for identifying critical mediators of local control of infection and stresses the importance of the constitutive antiviral state for the response to viral challenge.

scholarly journals HIF-1α Modulates Core Metabolism and Virus Replication in Primary Airway Epithelial Cells Infected with Respiratory Syncytial Virus

Viruses ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1088
Author(s):  
Dorothea R. Morris ◽  
Yue Qu ◽  
Anurodh Agrawal ◽  
Roberto P. Garofalo ◽  
Antonella Casola
Keyword(s):  
Respiratory Syncytial Virus ◽  
Epithelial Cells ◽  
Cellular Metabolism ◽  
Airway Epithelial Cells ◽  
Alveolar Epithelial Cells ◽  
Metabolic Reprogramming ◽  
Host Cells ◽  
Oxygen Utilization ◽  
Hexokinase Ii ◽  
Syncytial Virus

Metabolic reprogramming of host cells is key to the foundation of a successful viral infection. Hypoxia inducible factors (HIFs) mediate oxygen utilization by regulating cellular metabolism and redox homeostasis. Under normoxic conditions, HIF proteins are synthesized and subsequently degraded following ubiquitination to allow for normal metabolic activities. Recent studies suggest that respiratory syncytial virus (RSV) has the ability to induce HIF-1α stabilization and accumulation through non-hypoxic mechanisms. This makes the HIF pathway a potential avenue of approach for RSV therapeutic development. Using a model of primary human small alveolar epithelial cells, we demonstrate RSV infections to greatly alter cellular metabolism in favor of the glycolytic and pentose phosphate pathways. Additionally, we show RSV infections to stabilize HIF-1α and HIF-2α expression in these cells. Inhibition of HIF-1α, but not HIF-2α, was found to significantly reduce RSV replication as well as the glycolytic pathway, as measured by the expression of hexokinase II. Our study contributes to the understanding of RSV-mediated changes to cellular metabolism and supports further investigation into anti-HIF-1α therapeutics for RSV infections.

scholarly journals Elevated temperature triggers human respiratory syncytial virus F protein six-helix bundle formation

Virology ◽  
2010 ◽  
Vol 396 (2) ◽  
pp. 226-237 ◽  
Author(s):  
Abdul S. Yunus ◽  
Trent P. Jackson ◽  
Katherine Crisafi ◽  
Irina Burimski ◽  
Nicole R. Kilgore ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Elevated Temperature ◽  
Human Respiratory Syncytial Virus ◽  
F Protein ◽  
Helix Bundle ◽  
Syncytial Virus

scholarly journals Human Respiratory Syncytial Virus Glycoproteins Are Not Required for Apical Targeting and Release from Polarized Epithelial Cells

2008 ◽  
Vol 82 (17) ◽  
pp. 8664-8672 ◽  
Author(s):  
Melissa Batonick ◽  
Antonius G. P. Oomens ◽  
Gail W. Wertz
Keyword(s):  
Respiratory Syncytial Virus ◽  
Epithelial Cells ◽  
Apical Membrane ◽  
Human Respiratory Syncytial Virus ◽  
Viral Gene ◽  
Recombinant Viruses ◽  
Intracellular Targeting ◽  
Polarized Epithelial Cells ◽  
Syncytial Virus ◽  
Apical Sorting

ABSTRACT Human respiratory syncytial virus (HRSV) is released from the apical membrane of polarized epithelial cells. However, little is known about the processes of assembly and release of HRSV and which viral gene products are involved in the directional maturation of the virus. Based on previous studies showing that the fusion (F) glycoprotein contained an intrinsic apical sorting signal and that N- and O-linked glycans can act as apical targeting signals, we investigated whether the glycoproteins of HRSV were involved in its directional targeting and release. We generated recombinant viruses with each of the three glycoprotein genes deleted individually or in groups. Each deleted gene was replaced with a reporter gene to maintain wild-type levels of gene expression. The effects of deleting the glycoprotein genes on apical maturation and on targeting of individual proteins in polarized epithelial cells were examined by using biological, biochemical, and microscopic assays. The results of these studies showed that the HRSV glycoproteins are not required for apical maturation or release of the virus. Further, deletion of one or more of the glycoprotein genes did not affect the intracellular targeting of the remaining viral glycoproteins or the nucleocapsid protein to the apical membrane.

scholarly journals Characterization of the epitope for anti-human respiratory syncytial virus F protein monoclonal antibody 101F using synthetic peptides and genetic approaches

2007 ◽  
Vol 88 (10) ◽  
pp. 2719-2723 ◽  
Author(s):  
Sheng-Jiun Wu ◽  
Albert Schmidt ◽  
Eric J. Beil ◽  
Nicole D. Day ◽  
Patrick J. Branigan ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Antigenic Site ◽  
Neutralizing Antibody ◽  
Human Respiratory Syncytial Virus ◽  
Peptide Sequence ◽  
F Protein ◽  
Syncytial Virus ◽  
A Minor ◽  
Key Residues

Chimeric 101F (ch101F) is a mouse–human chimeric anti-human respiratory syncytial virus (HRSV) neutralizing antibody that recognizes residues within antigenic site IV, V, VI of the fusion (F) glycoprotein. The binding of ch101F to a series of peptides overlapping aa 422–438 spanning antigenic site IV, V, VI was analysed. Residues 423–436 comprise the minimal peptide sequence for ch101F binding. Substitution analysis revealed that R429 and K433 are critical for ch101F binding, whilst K427 makes a minor contribution. Binding of ch101F to a series of single mutations at positions 427, 429 and 433 in the F protein expressed recombinantly on the cell surface confirmed the peptide results. Sequence analysis of viruses selected for resistance to neutralization by ch101F indicated that a single change (K433T) in the F protein allowed ch101F escape. The results confirm that ch101F and palivizumab have different epitope specificity and define key residues for ch101F recognition.

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