Ovalbumin enhances YKL-40, IL-5, GM-CSF, and eotaxin expression simultaneously in primarily cultured mouse tracheal epithelial cells.

Epithelial inflammation and eosinophil infiltration are crucial for the pathogenesis of asthma. Many inflammatory mediators, such as YKL-40, interleukin -5 (IL-5), granulocyte-macrophage colony-stimulating factor (GM-CSF), and eotaxin, are important for the development of allergic airway inflammation. This study is aimed at investigating the impact of treatment with ovalbumin (OVA) on the levels of those inflammatory mediators in primarily cultured mouse tracheal epithelial cells. Mouse tracheal epithelial cells were isolated and identified by immunofluorescent staining; the isolated mouse tracheal epithelial cells expressed cytokeratins. Treatment with OVA for 24 or 48 h significantly increased the relative levels of YKL-40, IL-5, GM-CSF, and eotaxin mRNA transcripts and YKL-40, IL-5, GM-CSF, and eotaxin proteins secreted in the supernatants of cultured cells, as compared with that in the untreated control cells (P < 0.01, P < 0.05, respectively). The levels of YKL-40 expression were correlated positively with the levels of IL-5, GM-CSF, and eotaxin expression in the OVA-treated cells. These data indicated that treatment with OVA simultaneously enhanced YKL-40, IL-5, GM-CSF, and eotaxin expression in the cultured mouse tracheal epithelial cells in vitro. These inflammatory mediators may synergistically contribute to the pathogenesis of allergic inflammation, and this study may help to understand the role of YKL-40 in the pathogenesis of asthma.