scholarly journals Lytic Cell Death Mechanisms in Human Respiratory Syncytial Virus-Infected Macrophages: Roles of Pyroptosis and Necroptosis

Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 932
Author(s):  
Lori Bedient ◽  
Swechha Mainali Pokharel ◽  
Kim R. Chiok ◽  
Indira Mohanty ◽  
Sierra S. Beach ◽  
...  
Keyword(s):  
Cell Death ◽  
Respiratory Syncytial Virus ◽  
Kinase Domain ◽  
Human Respiratory Syncytial Virus ◽  
Inflammasome Activation ◽  
Pyrin Domain ◽  
Cellular Debris ◽  
Rsv Infection ◽  
Syncytial Virus ◽  
Cell Death Mechanisms

Human respiratory syncytial virus (RSV) is the most common cause of viral bronchiolitis and pneumonia in infants and children worldwide. Inflammation induced by RSV infection is responsible for its hallmark manifestation of bronchiolitis and pneumonia. The cellular debris created through lytic cell death of infected cells is a potent initiator of this inflammation. Macrophages are known to play a pivotal role in the early innate immune and inflammatory response to viral pathogens. However, the lytic cell death mechanisms associated with RSV infection in macrophages remains unknown. Two distinct mechanisms involved in lytic cell death are pyroptosis and necroptosis. Our studies revealed that RSV induces lytic cell death in macrophages via both of these mechanisms, specifically through the ASC (Apoptosis-associated speck like protein containing a caspase recruitment domain)-NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3) inflammasome activation of both caspase-1 dependent pyroptosis and receptor-interacting serine/threonine-protein kinase 3 (RIPK3), as well as a mixed lineage kinase domain like pseudokinase (MLKL)-dependent necroptosis. In addition, we demonstrated an important role of reactive oxygen species (ROS) during lytic cell death of RSV-infected macrophages.

scholarly journals Evaluation of the Safety and Immune Efficacy of Recombinant Human Respiratory Syncytial Virus Strain Long Live Attenuated Vaccine Candidates

2021 ◽  
Author(s):  
Li-Nan Wang ◽  
Xiang-Lei Peng ◽  
Min Xu ◽  
Yuan-Bo Zheng ◽  
Yue-Ying Jiao ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Gene Deletion ◽  
Human Respiratory Syncytial Virus ◽  
Temperature Sensitive ◽  
T7 Promoter ◽  
Vaccine Candidates ◽  
Rsv Infection ◽  
Syncytial Virus

AbstractHuman respiratory syncytial virus (RSV) infection is the leading cause of lower respiratory tract illness (LRTI), and no vaccine against LRTI has proven to be safe and effective in infants. Our study assessed attenuated recombinant RSVs as vaccine candidates to prevent RSV infection in mice. The constructed recombinant plasmids harbored (5′ to 3′) a T7 promoter, hammerhead ribozyme, RSV Long strain antigenomic cDNA with cold-passaged (cp) mutations or cp combined with temperature-sensitive attenuated mutations from the A2 strain (A2cpts) or further combined with SH gene deletion (A2cptsΔSH), HDV ribozyme (δ), and a T7 terminator. These vectors were subsequently co-transfected with four helper plasmids encoding N, P, L, and M2-1 viral proteins into BHK/T7-9 cells, and the recovered viruses were then passaged in Vero cells. The rescued recombinant RSVs (rRSVs) were named rRSV-Long/A2cp, rRSV-Long/A2cpts, and rRSV-Long/A2cptsΔSH, respectively, and stably passaged in vitro, without reversion to wild type (wt) at sites containing introduced mutations or deletion. Although rRSV-Long/A2cpts and rRSV-Long/A2cptsΔSH displayed  temperature-sensitive (ts) phenotype in vitro and in vivo, all rRSVs were significantly attenuated in vivo. Furthermore, BALB/c mice immunized with rRSVs produced Th1-biased immune response, resisted wtRSV infection, and were free from enhanced respiratory disease. We showed that the combination of ΔSH with attenuation (att) mutations of cpts contributed to improving att phenotype, efficacy, and gene stability of rRSV. By successfully introducing att mutations and SH gene deletion into the RSV Long parent and producing three rRSV strains, we have laid an important foundation for the development of RSV live attenuated vaccines.

scholarly journals A genetic model of differential susceptibility to human respiratory syncytial virus (RSV) infection

2014 ◽  
Vol 28 (4) ◽  
pp. 1947-1956 ◽  
Author(s):  
Jonathan M. Ciencewicki ◽  
Xuting Wang ◽  
Jacqui Marzec ◽  
M. Elina Serra ◽  
Douglas A. Bell ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Genetic Model ◽  
Differential Susceptibility ◽  
Human Respiratory Syncytial Virus ◽  
Rsv Infection ◽  
Syncytial Virus

scholarly journals Human respiratory syncytial virus viroporin SH: a viral recognition pathway used by the host to signal inflammasome activation

Thorax ◽  
2012 ◽  
Vol 68 (1) ◽  
pp. 66-75 ◽  
Author(s):  
Kathy Triantafilou ◽  
Satwik Kar ◽  
Emmanouil Vakakis ◽  
Sailesh Kotecha ◽  
Martha Triantafilou
Keyword(s):  
Respiratory Syncytial Virus ◽  
Human Respiratory Syncytial Virus ◽  
Inflammasome Activation ◽  
Syncytial Virus ◽  
Viral Recognition

scholarly journals Effects of neutrophil extracellular traps during human respiratory syncytial virus infection in vitro

2023 ◽  
Vol 83 ◽  
Author(s):  
L.F.A. Diniz ◽  
B.K. Matsuba ◽  
P.S.S. Souza ◽  
B.R.P. Lopes ◽  
L.H. Kubo ◽  
...  
Keyword(s):  
Cell Death ◽  
Respiratory Syncytial Virus ◽  
Neutrophil Extracellular Traps ◽  
Human Respiratory Syncytial Virus ◽  
Intense Staining ◽  
Extracellular Traps ◽  
Previous Contact ◽  
Acute Respiratory Diseases ◽  
Syncytial Virus

Abstract The human respiratory syncytial virus (hRSV) is the most common cause of severe lower respiratory tract diseases in young children worldwide, leading to a high number of hospitalizations and significant expenditures for health systems. Neutrophils are massively recruited to the lung tissue of patients with acute respiratory diseases. At the infection site, they release neutrophil extracellular traps (NETs) that can capture and/or inactivate different types of microorganisms, including viruses. Evidence has shown that the accumulation of NETs results in direct cytotoxic effects on endothelial and epithelial cells. Neutrophils stimulated by the hRSV-F protein generate NETs that are able to capture hRSV particles, thus reducing their transmission. However, the massive production of NETs obstructs the airways and increases disease severity. Therefore, further knowledge about the effects of NETs during hRSV infections is essential for the development of new specific and effective treatments. This study evaluated the effects of NETs on the previous or posterior contact with hRSV-infected Hep-2 cells. Hep-2 cells were infected with different hRSV multiplicity of infection (MOI 0.5 or 1.0), either before or after incubation with NETs (0.5–16 μg/mL). Infected and untreated cells showed decreased cellular viability and intense staining with trypan blue, which was accompanied by the formation of many large syncytia. Previous contact between NETs and cells did not result in a protective effect. Cells in monolayers showed a reduced number and area of syncytia, but cell death was similar in infected and non-treated cells. The addition of NETs to infected tissues maintained a similar virus-induced cell death rate and an increased syncytial area, indicating cytotoxic and deleterious damages. Our results corroborate previously reported findings that NETs contribute to the immunopathology developed by patients infected with hRSV.

scholarly journals GBP5 Is an Interferon-Induced Inhibitor of Respiratory Syncytial Virus

2020 ◽  
Vol 94 (21) ◽  
Author(s):  
Zhaolong Li ◽  
Xinglong Qu ◽  
Xin Liu ◽  
Chen Huan ◽  
Hong Wang ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
G Protein ◽  
E3 Ligase ◽  
Multiple Infections ◽  
Inflammasome Activation ◽  
Pathogenic Mechanisms ◽  
Rsv Infection ◽  
Ifn Γ ◽  
Syncytial Virus ◽  
Small Hydrophobic

ABSTRACT Guanylate binding protein 5 (GBP5) belongs to the GTPase subfamily, which is mainly induced by interferon gamma (IFN-γ) and is involved in many important cellular processes, including inflammasome activation and innate immunity against a wide variety of microbial pathogens. However, it is unknown whether GBP5 inhibits respiratory syncytial virus (RSV) infection. In this study, we identified GBP5 as an effector of the anti-RSV activity of IFN-γ and found that in children, the weaker immune response, especially the weaker IFN-γ response and the decreased GBP5 expression, leads to RSV susceptibility. Furthermore, we revealed that GBP5 reduced the cell-associated levels of the RSV small hydrophobic (SH) protein, which was identified as a viroporin. In contrast, overexpression of the SH protein rescued RSV replication in the presence of GBP5. The GBP5-induced decrease in intracellular SH protein levels is because GBP5 promotes the release of the SH protein into the cell culture. Moreover, the GBP5 C583A mutants with changes at the C terminus or the GBP5 ΔC mutant lacking the C-terminal region, which impairs GBP5 localization in the Golgi, could not inhibit RSV infection, whereas the GTPase-defective GBP5 maintained RSV inhibition, suggesting that Golgi localization but not the GTPase activity of GBP5 is required for RSV inhibition. Interestingly, we found that RSV infection or RSV G protein downregulates GBP5 expression by upregulating DZIP3, an E3 ligase, which induces GBP5 degradation through the K48 ubiquitination and proteasomal pathways. Thus, this study reveals a complicated interplay between host restrictive factor GBP5 and RSV infection and provides important information for understanding the pathogenesis of RSV. IMPORTANCE RSV is a highly contagious virus that causes multiple infections in infants within their first year of life. It can also easily cause infection in elderly or immunocompromised individuals, suggesting that individual differences in immunity play an important role in RSV infection. Therefore, exploring the pathogenic mechanisms of RSV and identifying essential genes which inhibit RSV infection are necessary to develop an effective strategy to control RSV infection. Here, we report that the IFN-inducible gene GBP5 potently inhibits RSV replication by reducing the cell-associated levels of the RSV small hydrophobic (SH) protein, which is a viroporin. In contrast, the RSV G protein was shown to upregulate the expression of the DZIP3 protein, an E3 ligase that degrades GBP5 through the proteasomal pathway. Our study provides important information for the understanding of the pathogenic mechanisms of RSV and host immunity as well as the complicated interplay between the virus and host.

scholarly journals Human Respiratory Syncytial Virus Nonstructural Protein NS2 Antagonizes the Activation of Beta Interferon Transcription by Interacting with RIG-I

2009 ◽  
Vol 83 (8) ◽  
pp. 3734-3742 ◽  
Author(s):  
Zhenhua Ling ◽  
Kim C. Tran ◽  
Michael N. Teng
Keyword(s):  
Respiratory Syncytial Virus ◽  
Nonstructural Protein ◽  
Early Time ◽  
Human Respiratory Syncytial Virus ◽  
Wild Type ◽  
Promoter Activation ◽  
Rsv Infection ◽  
Infected Cells ◽  
Syncytial Virus ◽  
Irf3 Activation

ABSTRACT A wide variety of RNA viruses have been shown to produce proteins that inhibit interferon (IFN) production and signaling. For human respiratory syncytial virus (RSV), the nonstructural NS1 and NS2 proteins have been shown to block IFN signaling by causing the proteasomal degradation of STAT2. In addition, recombinant RSVs lacking either NS1 or NS2 induce more IFN production than wild-type (wt) RSV in infected cells. However, the mechanisms by which the NS proteins perform this function are unknown. In this study, we focused on defining the mechanism by which NS2 inhibits the induction of IFN transcription. We find that NS2 is required for the early inhibition of IFN transcription since the infection of cells with NS2-deletion RSV resulted in a higher level of IRF3 activation at early time points postinfection compared with that of wt or NS1-deletion RSV infection. In addition, NS2 expression inhibits IFN transcription induced by both the RIG-I and TLR3 pathways. Furthermore, we show that NS2 inhibits RIG-I-mediated IFN promoter activation by binding to the N-terminal CARD of RIG-I and inhibiting its interaction with the downstream component MAVS (IPS-1, VISA, Cardif). Thus, the RSV NS2 protein is a multifunctional IFN antagonist that targets specific components of both the IFN induction and IFN signaling pathways.

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