Augmentation of Pulmonary Epithelial Cell IL-8 Expression and Permeability by Pre-B-cell Colony Enhancing Factor.
BACKGROUND
Previous studies in our lab have identified Pre-B-cell colony enhancing factor (PBEF) as a novel biomarker in acute lung injury (ALI). The molecular mechanism of PBEF involvement in the pathogenesis of ALI is still incompletely understood. This study examined the role of PBEF in regulating pulmonary alveolar epithelial cell IL-8 expression and permeability.


METHODS
Human pulmonary alveolar epithelial cells (cell line and primary cells) were transfected with human PBEF cDNA or PBEF siRNA and then cultured in the presence or absence of TNFalpha. PBEF and IL-8 expression were analyzed by RT-PCR and Western blotting. In addition, changes in pulmonary alveolar epithelial and artery endothelial cell barrier regulation with altered PBEF expression was evaluated by an in vitro cell permeability assay.


RESULTS
Our results demonstrated that, in human pulmonary alveolar epithelial cells, the overexpression of PBEF significantly augmented basal and TNFalpha-stimulated IL-8 secretion by more than 5 to 10-fold and increased cell permeability by >30%; the knockdown of PBEF expression with siRNA significantly inhibited basal and TNFalpha-stimulated IL-8 secretion by 70% and IL-8 mRNA levels by 74%. Further, the knockdown of PBEF expression also significantly attenuated TNFalpha-induced cell permeability by 43%. Similar result was observed in human pulmonary artery endothelial cells.


CONCLUSIONS
These results suggest that PBEF may play a vital role in basal and TNFalpha-mediated pulmonary inflammation and pulmonary epithelial barrier dysfunction via its regulation of other inflammatory cytokines such as IL-8, which could in part explain the role of PBEF in the susceptibility and pathogenesis of ALI. These results lend further support to the potential of PBEF to serve as a diagnostic and therapeutic target to ALI.
Li
Hailong
H
Department of Surgery, University of Missouri School of Medicine, Columbia, MO 65212, USA.|Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Columbia, MO 65212, USA.
Liu
Peng
P
Department of Surgery, University of Missouri School of Medicine, Columbia, MO 65212, USA.|Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Columbia, MO 65212, USA.
Cepeda
Javier
J
Department of Surgery, University of Missouri School of Medicine, Columbia, MO 65212, USA.|Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Columbia, MO 65212, USA.
Fang
Deyu
D
Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Columbia, MO 65212, USA.|Department of Otolaryngology, University of Missouri School of Medicine, Columbia, MO 65212, USA.
Easley
R Blaine
RB
Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University, Baltimore, MD 21205, USA.
Simon
Brett A
BA
Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University, Baltimore, MD 21205, USA.|Department of Medicine, The Johns Hopkins University, Baltimore, MD 21205, USA.
Zhang
Li Qin
LQ
Department of Surgery, University of Missouri School of Medicine, Columbia, MO 65212, USA.|Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Columbia, MO 65212, USA.
Ye
Shui Qing
SQ
Department of Surgery, University of Missouri School of Medicine, Columbia, MO 65212, USA.|Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Columbia, MO 65212, USA.