Role of retinoic acid inducible gene-I in human metapneumovirus-induced cellular signalling

Human metapneumovirus (HMPV) is a recently discovered pathogen that causes a significant proportion of respiratory infections in young infants, the elderly and immunocompromised patients. Very little is known regarding the cellular signalling elicited by this virus in airway epithelial cells, the target of HMPV infection. In this study, we investigated the role of the RNA helicases retinoic acid inducible gene-I (RIG-I) and melanoma differentiation-associated gene-5 (MDA-5) as the main pattern recognition receptors (PRRs) involved in viral detection and subsequent expression of proinflammatory and antiviral genes. HMPV infection readily induced RIG-I and MDA-5 gene and protein expression in A549 cells, a type II-like alveolar epithelial cell line. Expression of dominant-negative (DN) RIG-I or downregulation of RIG-I gene expression using small interfering RNA (siRNA) significantly decreased HMPV-induced beta interferon (IFN-β), interleukin (IL)-8 and RANTES gene transcription, by inhibiting viral-induced activation of nuclear factor (NF)-κB and interferon regulatory factor (IRF), leading to enhanced viral replication. On the other hand, MDA-5 did not seem to play a significant role in HMPV-induced cellular responses. Mitochondrial antiviral signalling protein (MAVS), an adaptor protein linking both RIG-I and MDA-5 to downstream activation of IRF-3 and NF-κB, was also necessary for HMPV-induced cellular signalling. Expression of a DN MAVS significantly reduced IFN-β and chemokine gene transcription, by inhibiting NF-κB- and IRF-dependent gene transcription, in response to HMPV infection. Our results show that HMPV activates the RIG-I–MAVS signalling pathway in airway epithelial cells, leading to the expression of important proinflammatory and antiviral molecules involved in the innate immune response to viruses.

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Human Metapneumovirus Impairs Apoptosis of Nasal Epithelial Cells in Asthma via HSP70

Journal of Innate Immunity ◽

10.1159/000449101 ◽

2016 ◽

Vol 9 (1) ◽

pp. 52-64 ◽

Cited By ~ 10

Author(s):

Engin Baturcam ◽

Natale Snape ◽

Tiong Han Yeo ◽

Johanna Schagen ◽

Emma Thomas ◽

...

Keyword(s):

Epithelial Cells ◽

Viral Infections ◽

Airway Epithelial Cells ◽

Human Metapneumovirus ◽

Airway Epithelial ◽

Caspase Activation ◽

Nasal Epithelial Cells ◽

Hmpv Infection ◽

Syncytial Virus

Asthmatics are highly susceptible to respiratory viral infections, possibly due to impaired innate immunity. However, the exact mechanisms of susceptibility are likely to differ amongst viruses. Therefore, we infected primary nasal epithelial cells (NECs) from adults with mild-to-moderate asthma, with respiratory syncytial virus (RSV) or human metapneumovirus (hMPV) in vitro and investigated the antiviral response. NECs from these asthmatics supported elevated hMPV but not RSV infection, compared to non-asthmatic controls. This correlated with reduced apoptosis and reduced activation of caspase-9 and caspase-3/7 in response to hMPV, but not RSV. The expression of heat shock protein 70 (HSP70), a known inhibitor of caspase activation and subsequent apoptosis, was amplified in response to hMPV infection. Chemical inhibition of HSP70 function restored caspase activation and reduced hMPV infection in NECs from asthmatic subjects. There was no impairment in the production of IFN by NECs from asthmatics in response to either hMPV or RSV, demonstrating that increased infection of asthmatic airway cells by hMPV is IFN-independent. This study demonstrates, for the first time, a mechanism for elevated hMPV infection in airway epithelial cells from adult asthmatics and identifies HSP70 as a potential target for antiviral and asthma therapies.

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Retinoic Acid-Inducible Gene I Mediates Early Antiviral Response and Toll-Like Receptor 3 Expression in Respiratory Syncytial Virus-Infected Airway Epithelial Cells

Journal of Virology ◽

10.1128/jvi.01740-06 ◽

2006 ◽

Vol 81 (3) ◽

pp. 1401-1411 ◽

Cited By ~ 211

Author(s):

Ping Liu ◽

Mohammad Jamaluddin ◽

Kui Li ◽

Roberto P. Garofalo ◽

Antonella Casola ◽

...

Keyword(s):

Retinoic Acid ◽

Respiratory Syncytial Virus ◽

Epithelial Cells ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Toll Like Receptor ◽

Isg15 Expression ◽

Rsv Infection ◽

Syncytial Virus ◽

Inducible Gene

ABSTRACT Respiratory syncytial virus (RSV) is one of the most common viral pathogens causing severe lower respiratory tract infections in infants and young children. Infected host cells detect and respond to RNA viruses using different mechanisms in a cell-type-specific manner, including retinoic acid-inducible gene I (RIG-I)-dependent and Toll-like receptor (TLR)-dependent pathways. Because the relative contributions of these two pathways in the recognition of RSV infection are unknown, we examined their roles in this study. We found that RIG-I helicase binds RSV transcripts within 12 h of infection. Short interfering RNA (siRNA)-mediated RIG-I “knockdown” significantly inhibited early nuclear factor-κB (NF-κB) and interferon response factor 3 (IRF3) activation 9 h postinfection (p.i.). Consistent with this finding, RSV-induced beta interferon (IFN-β), interferon-inducible protein 10 (IP-10), chemokine ligand 5 (CCL-5), and IFN-stimulated gene 15 (ISG15) expression levels were decreased in RIG-I-silenced cells during the early phase of infection but not at later times (18 h p.i.). In contrast, siRNA-mediated TLR3 knockdown did not affect RSV-induced NF-κB binding but did inhibit IFN-β, IP-10, CCL-5, and ISG15 expression at late times of infection. Further studies revealed that TLR3 knockdown significantly reduced NF-κB/RelA transcription by its ability to block the activating phosphorylation of NF-κB/RelA at serine residue 276. We further found that TLR3 induction following RSV infection was regulated by RIG-I-dependent IFN-β secreted from infected airway epithelial cells and was mediated by both IFN response-stimulated element (ISRE) and signal transducer and activator of transcription (STAT) sites in its proximal promoter. Together these findings indicate distinct temporal roles of RIG-I and TLR3 in mediating RSV-induced innate immune responses, which are coupled to distinct pathways controlling NF-κB activation.

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Role of size and composition of traffic and agricultural aerosols in the molecular responses triggered in airway epithelial cells

Inhalation Toxicology ◽

10.3109/08958378.2011.599445 ◽

2011 ◽

Vol 23 (11) ◽

pp. 627-640 ◽

Cited By ~ 25

Author(s):

Val Stéphanie ◽

Martinon Laurent ◽

Cachier Hélène ◽

Yahyaoui Abderrazak ◽

Marfaing Hélène ◽

...

Keyword(s):

Epithelial Cells ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Molecular Responses

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Role of Protein Kinase C‐alpha in Listeriolysin‐induced ENaC dysfunction in human airway epithelial cells

The FASEB Journal ◽

10.1096/fasebj.25.1_supplement.1039.22 ◽

2011 ◽

Vol 25 (S1) ◽

Author(s):

Guang Yang ◽

Richard White ◽

Martin Leustik ◽

Aluya Oseghale ◽

Mario Marrero ◽

...

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Epithelial Cells ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Human Airway ◽

Kinase C ◽

Protein Kinase C Alpha ◽

Human Airway Epithelial Cells

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Protective role of Indoleamine 2,3 dioxygenase in Respiratory Syncytial Virus associated immune response in airway epithelial cells

Virology ◽

10.1016/j.virol.2017.09.007 ◽

2017 ◽

Vol 512 ◽

pp. 144-150 ◽

Cited By ~ 2

Author(s):

Devi Rajan ◽

Raghavan Chinnadurai ◽

Evan L. O'Keefe ◽

Seyhan Boyoglu-Barnum ◽

Sean O. Todd ◽

...

Keyword(s):

Immune Response ◽

Respiratory Syncytial Virus ◽

Epithelial Cells ◽

Protective Role ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Indoleamine 2,3 Dioxygenase ◽

Syncytial Virus

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Lactosylated polyethylenimine for gene transfer into airway epithelial cells: role of the sugar moiety in cell delivery and intracellular trafficking of the complexes

The Journal of Gene Medicine ◽

10.1002/jgm.515 ◽

2004 ◽

Vol 6 (3) ◽

pp. 345-356 ◽

Cited By ~ 52

Author(s):

Stéphanie Grosse ◽

Yolande Aron ◽

Isabelle Honoré ◽

Guiti Thévenot ◽

Claire Danel ◽

...

Keyword(s):

Gene Transfer ◽

Epithelial Cells ◽

Intracellular Trafficking ◽

Airway Epithelial Cells ◽

Cell Delivery ◽

Airway Epithelial ◽

Sugar Moiety

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Airway epithelial tight junctions and binding and cytotoxicity ofPseudomonas aeruginosa

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1999.277.1.l204 ◽

1999 ◽

Vol 277 (1) ◽

pp. L204-L217 ◽

Cited By ~ 24

Author(s):

Alfred Lee ◽

Dar Chow ◽

Brian Haus ◽

Wanru Tseng ◽

David Evans ◽

...

Keyword(s):

Epithelial Cells ◽

Tight Junctions ◽

Propidium Iodide ◽

Time Course ◽

Living Cells ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Basolateral Membranes ◽

Free Edges

The role of tight junctions in the binding and cytoxicity of Pseudomonas aeruginosato apical or basolateral membranes of lung airway epithelial cells was tested with fluorescence microscopy on living cells. Binding of noncytotoxic P. aeruginosa strain O1 was assessed with P. aeruginosa that expressed green fluorescent protein. Binding of cytotoxic P. aeruginosa strain 6206 was assessed with FITC-labeled P. aeruginosa; cytotoxicity was determined from nuclear uptake of the impermeant dye propidium iodide. The role of direct contact of P. aeruginosa to epithelial cells was tested with filters with small (0.45-μm) or large (2.0-μm) pores. High transepithelial resistance ( Rt) Calu-3 and cultured bovine tracheal monolayers ( Rt> 1,000 Ω ⋅ cm2) bound P. aeruginosa very infrequently (<1 P. aeruginosa/100 cells) at the apical membrane, but P. aeruginosabound frequently to cells near “free edges” at holes, wounds, islands, and perimeters; cytotoxicity required direct interaction with basolateral membranes. Wounded high Rtepithelia showed increased P. aeruginosa binding and cytotoxicity at the free edges because basolateral membranes were accessible to P. aeruginosa, and dead and living cells near the wound bound P. aeruginosa similarly. Compared with high Rtepithelia, low RtCFT1 ( Rt= 100–200 Ω ⋅ cm2) and EGTA-treated Calu-3 monolayers were 25 times more susceptible to P. aeruginosa binding throughout the monolayer. Cytotoxicity to CFT1 cells (throughout the confluent monolayer, not only at the free edge) occurred after a shorter delay (0.25 vs. 2.0 h) and then five times faster than to Calu-3 cells, indicating that the time course of P. aeruginosa cytotoxicity may be limited by the rate of gaining access through tight junctions and that this occurred faster in low Rtthan in high Rtairway epithelia. Cytotoxicity appeared to occur in a sequential process that led first to a loss of fura 2 and a later uptake of propidium iodide. P. aeruginosa bound three times more frequently to regions between cells (tight junctions?) than to cell membranes of low RtCFT1 cells.

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