Anti-inflammatory effects of adiponectin in cigarette smoke-activated alveolar macrophage through the COX-2/PGE2 and TLRs signaling pathway

Objectives: Airway macrophages represents a central site for the mechanisms involved in the complex interactions between environmental triggers and airway inflammation. Based on anti-inflammatory activity of adiponectin, we hypothesize that adiponectin inhibits the proinflammatory cytokines production and the activation of alveolar macrophages expose to cigarette smoke. Materials and methods: To examine the effects of adiponectin on alveolar macrophages, we used the cigarette smoke-induced the alveolar inflammation model in C57BL/6 mice and the macrophages activation model in vitro, both in the presence or absence of adiponectin, to assess the accumulation of inflammatory cells and the concentration of inflammatory cytokines and chemokines in the bronchoalveolar lavage (BAL), and the proinflammatory cytokines production and M1/2 phenotype in alveolar macrophages. Results: Our results showed that adiponectin improves cigarette smoke-induced airway inflammation in vivo and decreases proinflammatory cytokine production and alveolar macrophages polarization in vitro. Moreover, our study further demonstrates that anti-inflammatory activity of adiponectin depends on the suppression of the proinflammatory cytokine production through TLR2/4 signaling and the inhibition of macrophage polarization vit COX-2/PGE2 signaling. Conclusions: Our study suggests that the anti-inflammatory activity of adiponectin might contribute to its therapeutic potential in airway inflammation, such as COPD.