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CCAAT/Enhancer-Binding Protein ? Is a Critical Regulator of IL-1ß-Induced IL-6 Production in Alveolar Epithelial Cells
Published: Friday, April 27, 2012
Author: Chunguang Yan et al.

by Chunguang Yan, Ximo Wang, Jay Cao, Min Wu, Hongwei Gao

CCAAT/enhancer binding protein ? (C/EBP?) is a member of the C/EBP family of transcription factors, which lacks known activation domains. C/EBP? was originally described as an inhibitor of C/EBP transactivation potential. However, previous study demonstrates that C/EBP? augments the C/EBPß stimulatory activity in lipopolysaccharide induction of IL-6 promoter in a B lymphoblast cell line. These data indicate a complexing functional role for C/EBP? in regulating gene expression. Furthermore, the expression and function of C/EBP? during inflammation are still largely unknown. In this study, we demonstrate that C/EBP? activation was induced by IL-1ß treatment in lung epithelial cells. Importantly, we demonstrate for the first time that C/EBP? plays a critical role in regulating IL-1ß-induced IL-6 expression in both mouse primary alveolar type II epithelial cells and a lung epithelial cell line, MLE12. We further provide the evidence that C/EBP? inhibits IL-6 expression by inhibiting C/EBPß but not NF-?B stimulatory activity in MLE12 cells. These findings suggest that C/EBP? is a key transcription factor that regulates the IL-6 expression in alveolar epithelial cells, and may play an important regulatory role in lung inflammatory responses.