Role of Double-Stranded RNA Pattern Recognition Receptors in Rhinovirus-Induced Airway Epithelial Cell Responses

Abstract

Rhinovirus (RV), a ssRNA virus of the picornavirus family, is a major cause of the common cold as well as asthma and chronic obstructive pulmonary disease exacerbations. Viral dsRNA produced during replication may be recognized by the host pattern recognition receptors TLR-3, retinoic acid-inducible gene (RIG)-I, and melanoma differentiation-associated gene (MDA)-5. No study has yet identified the receptor required for sensing RV dsRNA. To examine this, BEAS-2B human bronchial epithelial cells were infected with intact RV-1B or replication-deficient UV-irradiated virus, and IFN and IFN-stimulated gene expression was determined by quantitative PCR. The separate requirements of RIG-I, MDA5, and IFN response factor (IRF)-3 were determined using their respective small interfering RNAs (siRNA). The requirement of TLR3 was determined using siRNA against the TLR3 adaptor molecule Toll/IL-1R homologous region-domain-containing adapter-inducing IFN-β (TRIF). Intact RV-1B, but not UV-irradiated RV, induced IRF3 phosphorylation and dimerization, as well as mRNA expression of IFN-β, IFN-λ1, IFN-λ2/3, IRF7, RIG-I, MDA5, 10-kDa IFN-γ-inducible protein/CXCL10, IL-8/CXCL8, and GM-CSF. siRNA against IRF3, MDA5, and TRIF, but not RIG-I, decreased RV-1B-induced expression of IFN-β, IFN-λ1, IFN-λ2/3, IRF7, RIG-I, MDA5, and inflammatory protein-10/CXCL10 but had no effect on IL-8/CXCL8 and GM-CSF. siRNAs against MDA5 and TRIF also reduced IRF3 dimerization. Finally, in primary cells, transfection with MDA5 siRNA significantly reduced IFN expression, as it did in BEAS-2B cells. These results suggest that TLR3 and MDA5, but not RIG-I, are required for maximal sensing of RV dsRNA and that TLR3 and MDA5 signal through a common downstream signaling intermediate, IRF3.

Anti‐inflammatory effects of the novel inhaled phosphodiesterase type 4 inhibitor CHF6001 on virus‐inducible cytokines

“…2006; Wang et al. 2009), and that the data in this article presented as percentage of RV1B‐infected controls are based on statistically significant inductions of each cytokine measured.…”

“…2010; Wang et al. 2011, 2009). While there is some controversy over whether or not NF‐ κ B p65 is required for RV‐induced IFN transcription (Bartlett et al.…”

Novel antiviral properties of azithromycin in cystic fibrosis airway epithelial cells

“…We found that azithromycin treatment did not increase the percentage of annexin V-positive cells compared with untreated cells (fig. 3a, c and Azithromycin increases RV1B surface receptor and PRRs in RV1B-infected CF bronchial epithelial cells To assess whether an increase in virus entry and sensing contributes to the antiviral properties of azithromycin, the effect of azithromycin treatment on the expression of the RV1B surface receptor (LDLR) and PRRs involved in the recognition of RVs, such as TLR3, TLR2, RIG-I and MDA5 [24,29], was determined at 24 h post-infection ( fig. 4).…”

Interferon Regulatory Factor 6 Differentially Regulates Toll-like Receptor 2-dependent Chemokine Gene Expression in Epithelial Cells

“…macrophages and dendritic cells). Although IRF3 has also been shown to be important for TRIF-dependent TLR responses in epithelial cells (23)(24)(25), the IRF(s) that mediates MyD88-dependent responses in these cells is less clear. In contrast to other IRFs, IRF6 expression appears for the most part to be limited to epithelial cells (26 -30), where at least one function is to regulate cell proliferation and differentiation (27-29, 31, 32).…”