NF-κB-Induced MicroRNA-211 Inhibits Interleukin-10 in Macrophages of Rats with Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome.

BACKGROUND/AIMS: The present study addressed the potential involvement of microRNAs in acute respiratory distress syndrome (ARDS)-related inflammation and elucidates the underlying molecular mechanism.

METHODS: ARDS rat model was established by lipopolysaccharide, with compromised gas exchange capacity and lung edema. The inflammatory cells from bronchoalveolar lavage fluid (BALF) were profiled with automatic blood cell analyzer. The relative fluorescence intensity of BALF-derived macrophages was analyzed by flow cytometry. The relative microRNA expression was determined using microarray and Taqman assay. The secretory interleukin (IL)-10 was measured by enzyme-linked immunosorbent assay. Luciferase reporter assay was performed to determine the regulatory effects of miR-211 and NF-κB on IL-10 and miR-211 expressions, respectively. Chromatin immunoprecipitation (ChIP) was conducted to detect the direct binding of NK-κB on miR-211 promoter. The protein level was determined by Western blot.

RESULTS: The provoked acute inflammation was characterized with increased total cells, macrophages, neutrophils and lymphocytes. The relative expression of miR-211 was aberrantly up-regulated in BALF-derived macrophages from ARDS rats, which was accompanied with reduction of secretory IL-10. We further demonstrated that miR-211 inhibited IL-10 expression by binding to its 3'-UTR. The expression of miR-211 was modulated by NF-κB.

CONCLUSION: Here we elucidated a crucial role of NF-κB/miR-211/IL-10 signaling axis in ARDS-related inflammation.