Poly-l-Arginine Acts Synergistically with LPS to Promote the Release of IL-6 and IL-8 via p38/ERK Signaling Pathways in NCI-H292 Cells

Major basic protein (MBP) derived from activated eosinophil can exacerbate atopic asthma induced by lipopolysaccharide (LPS). The pharmacological function of MBP can be mimicked by poly-l-arginine (PLA), however, the potential signaling mechanisms of LPS-PLA-induced release of the inflammatory cytokines interleukin (IL)-6 and IL-8 remain unclear. In the present study, airway epithelia NCI-H292 cell lines were treated with LPS and/or PLA. We found that the expression levels of IL-6 and IL-8 induced by LPS-PLA were increased significantly compared with that in untreated cells. Meanwhile, the phosphorylation of p38 MAPK and ERK1/2 was also up-regulated dramatically by LPS-PLA, but this increase could be blocked by specific inhibitor. Importantly, blocking the phosphorylation of p38 MAPK and ERK1/2 reduced the expression levels of IL-6 and IL-8 as well. Collectively, LPS-PLA-induced release of IL-6 and IL-8 from NCI-H292 cells may be due to the synergistic activation of p38 MAPK and ERK1/2 signaling transduction pathways.