Cigarette smoke enhances human rhinovirus-induced CXCL8 production via HuR-mediated mRNA stabilization in human airway epithelial cells
نویسندگان
چکیده
BACKGROUND Human rhinovirus (HRV) triggers exacerbations of asthma and chronic obstructive pulmonary disease (COPD). Cigarette smoking is the leading risk factor for the development of COPD and 25% of asthmatics smoke. Smoking asthmatics have worse symptoms and more frequent hospitalizations compared to non-smoking asthmatics. The degree of neutrophil recruitment to the airways correlates with disease severity in COPD and during viral exacerbations of asthma. We have previously shown that HRV and cigarette smoke, in the form of cigarette smoke extract (CSE), each induce expression of the neutrophil chemoattractant and activator, CXCL8, in human airway epithelial cells. Additionally, we demonstrated that the combination of HRV and CSE induces expression of levels of CXCL8 that are at least additive relative to induction by each stimulus alone, and that enhancement of CXCL8 expression by HRV+CSE is regulated, at least in part, via mRNA stabilization. Here we further investigate the mechanisms by which HRV+CSE enhances CXCL8 expression. METHODS Primary human bronchial epithelial cells were cultured and treated with CSE alone, HRV alone or the combination of the two stimuli. Stabilizing/destabilizing proteins adenine/uridine-rich factor-1 (AUF-1), KH-type splicing regulatory protein (KHSRP) and human antigen R (HuR) were measured in cell lysates to determine expression levels following treatment. siRNA knockdown of each protein was used to assess their contribution to the induction of CXCL8 expression following treatment of cells with HRV and CSE. RESULTS We show that total expression of stabilizing/de-stabilizing proteins linked to CXCL8 regulation, including AUF-1, KHSRP and HuR, are not altered by CSE, HRV or the combination of the two stimuli. Importantly, however, siRNA-mediated knock-down of HuR, but not AUF-1 or KHSRP, abolishes the enhancement of CXCL8 by HRV+CSE. Data were analyzed using one-way ANOVA with student Newman-Keuls post hoc analysis and values of p≤ 0.05 were considered significant. CONCLUSIONS Induction of CXCL8 by the combination of HRV and CSE is regulated by mRNA stabilization involving HuR. Thus, targeting the HuR pathway may be an effective method of dampening CXCL8 production during HRV-induced exacerbations of lower airway disease, particularly in COPD patients and asthmatic patients who smoke.
منابع مشابه
Cigarette smoke modulates rhinovirus-induced airway epithelial cell chemokine production.
Human rhinovirus (HRV) infections induce epithelial cell production of chemokines that may contribute to the pathogenesis of exacerbations of chronic obstructive pulmonary disease (COPD) and asthma. Cigarette smoking is the predominant risk factor for the development of COPD and also aggravates asthma symptoms. We examined whether cigarette smoke extract (CSE) modulates viral inflammation by al...
متن کاملCyclic stretch augments human rhinovirus induced inflammatory responses in airway epithelial cells
Background Structural cells of the airways are subject to normal mechanical stretch during respiration [1]. Mechanical stretch acts as a mechanism of cell activation, and mechanotransduction pathways have been shown to activate pro-inflammatory genes [2]. Human rhinovirus (HRV) infections are a major cause of asthma exacerbations, and mechanical forces are likely to be more pronounced during as...
متن کاملα1-Antitrypsin reduces rhinovirus infection in primary human airway epithelial cells exposed to cigarette smoke
Human rhinovirus (HRV) infections target airway epithelium and are the leading cause of acute exacerbations of COPD. Cigarette smoke (CS) increases the severity of viral infections, but there is no effective therapy for HRV infection. We determined whether α1-antitrypsin (A1AT) reduces HRV-16 infection in CS-exposed primary human airway epithelial cells. Brushed bronchial epithelial cells from ...
متن کاملInterleukin-17A modulates human airway epithelial responses to human rhinovirus infection.
Human rhinovirus (HRV) infections are associated with exacerbations of asthma and chronic obstructive pulmonary disease that are characterized by a selective neutrophil infiltration. IL-17A, a cytokine derived primarily from activated T cells, has been linked to neutrophilic inflammation of the airways. We hypothesized that IL-17A alters the response of HRV-infected epithelial cells to modulate...
متن کاملCigarette smoke induces CXCL8 production by human neutrophils via activation of TLR9 receptor.
Chronic obstructive pulmonary disease (COPD) is a major health problem and cigarette smoke is the main risk factor for the development of COPD. The characteristic changes in airway morphology, inflammatory cell infiltration and mediator expression in COPD may result from direct effects of cigarette smoke on airway cells. Toll-like receptors (TLRs) are key elements in pathogen recognition by the...
متن کامل