MiR-146a regulates PM1-induced inflammation via NF-κB signaling pathway in BEAS-2B cells

Exposure to particulate matter (PM) leads to kinds of cardiopulmonary diseases, such as asthma, COPD, arrhythmias, lung cancer, etc., which are related to PM-induced inflammation. We have found that PM2.5 (aerodynamics diameter <2.5 mu m) exposure induces inflammatory response both in vivo and in vitro. Since the toxicity of PM is tightly associated with its size and components, PM1 (aerodynamics diameter <1.0 mu m) is supposed to be more toxic than PM2.5. However, the mechanism of PM1-induced inflammation is not clear. Recently, emerging evidences prove that microRNAs play a vital role in regulating inflammation. Therefore, we studied the regulation of miR-146a in PM1-induced inflammation in human lung bronchial epithelial BEAS-2B cells. The results show that PM1 induces the increase of IL-6 and IL-8 in BEAS-2B cells and up-regulates the miR-146a expression by activating NF-B signaling pathway. Overexpressed miR-146a prevents the nuclear translocation of p65 through inhibiting the IRAK1/TRAF6 expression, and downregulates the expression of IL-6 and IL-8. Taken together, these results demonstrate that miR-146a can negatively feedback regulate PM1-induced inflammation via NF-B signaling pathway in BEAS-2B cells.