Bradykinin- and lipopolysaccharide-induced bradykinin B2 receptor expression, interleukin 8 release and nitrosative stress in bronchial epithelial cells BEAS-2B: Role for neutrophils

Bradykinin-induced interleukin (IL)-8 release should potentially activate neutrophils releasing myeloperoxidase (MPO) and subsequently generating nitrosative stress. We studied bradykinin-induced expression of bradykinin B₂ receptor and bradykinin- and lipopolysaccharide (LPS)-induced IL-8 release, MPO (marker of neutrophil activation) and 3-nitrotyrosine (3-NT; marker of nitrosative stress) production in human bronchial epithelial cells BEAS-2B alone or in co-culture with human neutrophils. We evaluated B ₂ receptor protein expression in BEAS-2B cells by immunostainings and Western blot analysis, and measured respectively bradykinin- or LPS-induced IL-8 release in BEAS-2B cells and bradykinin- and/or LPS-induced MPO and 3-NT production in BEAS-2B cells co-cultured with human neutrophils by ELISA. In addition, we evaluated bradykinin- and/or LPS-induced 3-NT formation in BEAS-2B cells co-cultured with human neutrophils by immunocytochemistry. Bradykinin up-regulates B₂ receptor expression (P2 receptor antagonist HOE 140 or the selective bradykinin B ₁ receptor antagonist Lys-(des-Arg⁹, Leu ⁸)-bradykinin alone halved IL-8 release and the combination of both drugs suppressed this effect. In BEAS-2B cells co-cultured with human neutrophils bradykinin increased MPO release and 3-NT production compared to BEAS-2B cells with human neutrophils (P