초록
BACKGROUND: The underlying mechanisms for infantile bronchopneumonia development remain unknown. METHODS: Peripheral blood mononuclear cell (PBMCs) and serum derived from severe and mild infantile bronchopneumonia were obtained, and the expression of various molecules was detected with enzyme-linked immunosorbent assay and quantitative PCR. Such molecules were also detected in granulocyte-macrophage colony-stimulating factor (GM-CSF)-induced bone marrow-derived NFκB2-/- dendritic cells (DCs) or NIK SMI1 (NF-κB-inducing kinase inhibitor) administrated DCs. RESULTS: The relative mRNA expression levels of type I interferons (IFNs) (IFN-α4, IFN-β), Th17 cell-associated markers (interleukin-17A, retinoic-acid-receptor-related orphan nuclear receptor gamma, and GM-CSF), and non-canonical NF-κB member (NFκB2) were significantly up-regulated in PBMCs and DCs derived from infantile bronchopneumonia compared with healthy controls. However, compared with Th17 cell-associated markers and non-canonical NF-κB molecules, the expression of IFN-α4 and IFN-β was significantly inhibited in severe infantile bronchopneumonia compared with mild infantile bronchopneumonia. The relative protein expression of the above molecules also showed a similar expression pattern in the PBMCs or serum. NF-κB2 knockout or NIK SMI1 administration could reverse the diminished expression of IFN-β in GM-CSF-induced bone marrow-derived DCs. CONCLUSIONS: GM-CSF-dependent non-canonical NF-κB pathway-mediated inhibition of type I IFNs production in DCs contributes to the development of severe bronchopneumonia in infant. IMPACT: Granulocyte-macrophage colony-stimulating factor-dependent non-canonical NF-κB pathway-mediated inhibition of type I IFNs production in dendritic cells is critical for the development of infantile bronchopneumonia. Our findings reveal a possible mechanism underlying the development of severe infantile bronchopneumonia. The results could provide therapeutic molecular target for the treatment of such disease.