PKC Activation Induces Inflammatory Response and Cell Death in Human Bronchial Epithelial Cells

A variety of airborne pathogens can induce inflammatory responses in airway epithelial cells, which is a crucial component of host defence. However, excessive inflammatory responses and chronic inflammation also contribute to different diseases in the respiratory system. We hypothesized that the activation of protein kinase C (PKC) is one of the essential mechanisms of inflammatory responses in airway epithelial cells. In the present study, we stimulated human bronchial lung epithelial (BEAS-2B) cells with phorbol ester Phorbol 12, 13-dibutyrate (PDBu), and examined gene expression profile with microarray analysis. Bioinformatics suggested that PKC activation induced dramatic changes in gene expression related to multiple cellular functions. The top two functional networks of genes were centered on NFB and TNF-, which are two commonly known pathways for cell death and inflammation. Subsequent tests confirmed the decrease in cell viability and increase in the production of various cytokines. Interestingly, each of the increased cytokines was differentially regulated at mRNA and/or protein levels by different sub-class of PKC isozymes. We conclude that many pathogen-induced cell death and cytokine production in airway epithelial cells may be mediated through PKC related signaling pathways. These findings suggest that PKCs can be new targets for treatments of lung diseases.

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Kim H, Zamel R, Bai XH, Liu M