摘要

Children with acute respiratory syncytial virus (RSV) infection often develop sequelae of persistent airway inflammation and wheezing. Pulmonary C fibers (PCFs) are involved in the generation of airway inflammation and resistance; however, their role in persistent airway diseases after RSV is unexplored. Here, we elucidated the pathogenesis of PCF activation in RSV-induced persistent airway disorders. PCF-degenerated and intact mice were used in the current study. Airway inflammation and airway resistance were evaluated. MMP408 and FSLLRY-NH2 were the selective antagonists for MMP-12 and PAR2, respectively, to investigate the roles of MMP-12 and PAR2 in PCFs mediating airway diseases. As a result, PCF degeneration significantly reduced the following responses to RSV infection: augmenting of inflammatory cells, especially macrophages, and infiltrating of inflammatory cells in lung tissues; specific airway resistance (sRaw) response to methacholine; and upregulation of MMP-12 and PAR2 expression. Moreover, the inhibition of MMP-12 reduced the total number of cells and macrophages in bronchiolar lavage fluid (BALF), as well infiltrating inflammatory cells, and decreased the sRaw response to methacholine. In addition, PAR2 was up-regulated especially at the later stage of RSV infection. Downregulation of PAR2 ameliorated airway inflammation and resistance following RSV infection and suppressed the level of MMP-12. In all, the results suggest that PCF involvement in long-term airway inflammation and airway hyperresponsiveness occurred at least partially via modulating MMP-12, and the activation of PAR2 might be related to PCF-modulated MMP-12 production. Our initial findings indicated that the inhibition of PCF activity would be targeted therapeutically for virus infection-induced long-term airway disorders. @@@ IMPORTANCE @@@ The current study is critical to understanding that PCFs are involved in long-term airway inflammation and airway resistance after RSV infection through mediating MMP-12 production via PAR2, indicating that the inhibition of PCF activity can be targeted therapeutically for virus infection-induced long-term airway disorders.