Decreased expression of the NF-κB family member RelB in lung fibroblasts from Smokers with and without COPD potentiates cigarette smoke-induced COX-2 expression. Issue 1 (December 2015)

• Record Type: Journal Article
• Authors: Sheridan, Jared; Zago, Michela; Nair, Parameswaran; Li, Pei; Bourbeau, Jean; Tan, Wan; Hamid, Qutayba; Eidelman, David; Benedetti, Andrea; Baglole, Carolyn
• Is Part Of: Respiratory research. Volume 16:Issue 1(2015)
• Page Start: 1
• Page End: 16
• Publication Date: 2015-12
• Subjects: Inflammation -- NF-κB -- miRNA -- COPD -- Cigarette smoke -- Lung; Respiratory organs -- Diseases -- Periodicals; 616.2005
• DOI: 10.1186/s12931-015-0214-6
• Languages: English
• ISSNs: 1465-993X

Abstract

Abstract Background Heightened inflammation, including expression of COX-2, is associated with COPD pathogenesis. RelB is an NF-κB family member that attenuates COX-2 in response to cigarette smoke by a mechanism that may involve the miRNA miR-146a. There is no information on the expression of RelB in COPD or if RelB prevents COX-2 expression through miR-146a. Methods RelB, Cox-2 and miR-146a levels were evaluated in lung fibroblasts and blood samples derived from non-smokers (Normal) and smokers (At Risk) with and without COPD by qRT-PCR. RelB and COX-2 protein levels were evaluated by western blot. Human lung fibroblasts from Normal subjects and smokers with and without COPD, along with RelB knock-down (siRNA) in Normal cells, were exposed to cigarette smoke extract (CSE)in vitro and COX-2 mRNA/protein and miR-146a levels assessed. Results Basal expression of RelB mRNA and protein were significantly lower in lung cells derived from smokers with and without COPD, the latter of which expressed moreCox-2 mRNA and protein in response to CSE. Knock-down of RelB in Normal fibroblasts increasedCox-2 mRNA and protein induction by CSE. Basal miR-146a levels were not different between the three groups, and only Normal fibroblasts increased miR-146a expression in response to smoke. There was a positive correlation between systemic RelB andCox-2 mRNA levels and circulating miR-146a levels were higher only in GOLD stage I subjects. Conclusions Our data indicate that RelB attenuates COX-2 expression in lung structural cells, such that loss of pulmonary RelB may be an important determinant in the aberrant, heightened inflammation associated with COPD pathogenesis.