Respiratory syncytial virus activates epidermal growth factor receptor to suppress interferon regulatory factor 1-dependent interferon-lambda and antiviral defense in airway epithelium.

Respiratory syncytial virus (RSV) persists as a significant human pathogen that continues to contribute to morbidity and mortality. In children, RSV is the leading cause of lower respiratory tract infections, and in adults RSV causes pneumonia and contributes to exacerbations of chronic lung diseases. RSV induces airway epithelial inflammation by activation of the epidermal growth factor receptor (EGFR), a tyrosine kinase receptor. Recently, EGFR inhibition was shown to decrease RSV infection, but the mechanism(s) for this effect are not known. Interferon (IFN) signaling is critical for innate antiviral responses, and recent experiments have implicated IFN-λ (lambda), a type III IFN, as the most significant IFN for mucosal antiviral immune responses to RSV infection. However, a role for RSV-induced EGFR activation to suppress airway epithelial antiviral immunity has not been explored. Here, we show that RSV-induced EGFR activation suppresses IFN regulatory factor (IRF) 1-induced IFN-λ production and increased viral infection, and we implicate RSV F protein to mediate this effect. EGFR inhibition, during viral infection, augmented IRF1, IFN-λ, and decreased RSV titers. These results suggest a mechanism for EGFR inhibition to suppress RSV by activation of endogenous epithelial antiviral defenses, which may be a potential target for novel therapeutics.

Molecular impact of selective NFKB1 and NFKB2 signaling on DLBCL phenotype.

Diffuse large B-cell lymphoma (DLBCL) has been categorized into two molecular subtypes that have prognostic significance, namely germinal center B-cell like (GCB) and activated B-cell like (ABC). Although ABC-DLBCL has been associated with NF-κB activation, the relationships between activation of specific NF-κB signals and DLBCL phenotype remain unclear. Application of novel gene expression classifiers identified two new DLBCL categories characterized by selective p100 (NF-κB2) and p105 (NF-κB1) signaling. Interestingly, our molecular studies showed that p105 signaling is predominantly associated with GCB subtype and histone mutations. Conversely, most tumors with p100 signaling displayed ABC phenotype and harbored ABC-associated mutations in genes such as MYD88 and PIM1. In vitro, MYD88 L265P mutation promoted p100 signaling through TAK1/IKKα and GSK3/Fbxw7a pathways, suggesting a novel role for this protein as an upstream regulator of p100. p100 signaling was engaged during activation of normal B cells, suggesting p100's role in ABC phenotype development. Additionally, silencing p100 in ABC-DLBCL cells resulted in a GCB-like phenotype, with suppression of Blimp, IRF4 and XBP1 and upregulation of BCL6, whereas introduction of p52 or p100 into GC cells resulted in differentiation toward an ABC-like phenotype. Together, these findings identify specific roles for p100 and p105 signaling in defining DLBCL molecular subtypes and posit MYD88/p100 signaling as a regulator for B-cell activation.

The impact of pretransplant mechanical ventilation on short- and long-term survival after lung transplantation.

Lung transplantation in mechanically ventilated (MV) patients has been associated with decreased posttransplant survival. Under the Lung Allocation Score (LAS) system, patients at greatest risk of death on the waiting list, particularly those requiring MV, are prioritized for lung allocation. We evaluated whether pretransplant MV is associated with poorer posttransplant survival in the LAS era. Using a national registry, we analyzed all adults undergoing lung transplantation in the United States from 2005 to 2010. Propensity scoring identified nonventilated matched referents for 419 subjects requiring MV at the time of transplantation. Survival was evaluated using Kaplan-Meier methods. Risk of death was estimated by hazard ratios employing time-dependent covariates. We found that pretransplant MV was associated with decreased overall survival after lung transplantation. In the first 6 months posttransplant, ventilated subjects had a twofold higher risk of death compared to nonventilated subjects. However, after 6 months posttransplant, survival did not differ by MV status. We also found that pretransplant MV was not associated with decreased survival in noncystic fibrosis obstructive lung diseases. These results suggest that under the LAS, pretransplant MV is associated with poorer short-term survival posttransplant. Notably, the increased risk of death appears to be strongest the early posttransplant period and limited to certain pretransplant diagnoses.