Critical role of RIG-I-like receptors in inflammation in chronic obstructive pulmonary disease.

Abstract

IntroductionViral infection is a significant cause of chronic obstructive pulmonary disease (COPD) and acute exacerbation of COPD. Retinoic acid inducible gene I (RIG‐I)‐like receptors (RLRs), including RIG‐I and melanoma differentiation associated gene 5 (MDA‐5), are important pattern recognition receptors for viral elimination.ObjectiveThe study aims to investigate the role of RIG‐I and MDA‐5 in COPD pathogenesis.MethodsWe examined the expression of RIG‐I and MDA‐5 by immunohistochemistry, real‐time PCR and Western blots in COPD patients and control subjects.ResultsOur results showed that MDA‐5 expression was upregulated in lung tissues and peripheral blood mononuclear cells of COPD patients and there was a negative correlation between MDA‐5 mRNA levels and forced expiratory volume in 1 s %pred. COPD patients had higher interleukin (IL)‐1 and IL‐8 mRNA expression levels, and these inflammatory cytokines positively correlate with MDA‐5 levels. However, there was no difference in the expression of RIG‐I between COPD patients and control subjects.ConclusionOur results suggested that MDA‐5, but not RIG‐I, may play a critical role in airway inflammation in COPD.