title: TNFalpha-induced long pentraxin PTX3 expression in human lung epithelial cells via JNK.
abstract: Long pentraxin 3 (PTX3), an acute-phase protein, is a newly clarified mediator for innate immunity and inflammation. As a soluble pattern recognition receptor, it has a nonredundant role in antifungal infection. Overexpression of PTX3 worsens acute lung injury. The lung epithelium is a critical factor in defense against pulmonary pathogens; it is also involved in acute inflammatory responses related to tissue injury. However, very little is known about how PTX3 is regulated in the lung epithelium. In this study, we found that i.v. injection of LPS induced PTX3 expression in rat lung alveolar epithelium. Using human lung cell lines and primary epithelial cells, we found that PTX3 expression was significantly up-regulated by TNF-alpha in a time- and dose-dependent manner, but not by LPS. Pretreatment with either actinomycin D or cycloheximide abolished TNF-alpha-induced PTX3 expression, indicating the requirement for both transcriptional and translational regulation. The TNF-alpha-induced PTX3 expression was blocked by SP600125, a JNK-specific inhibitor, but not by the inhibitors against NF-kappaB, ERKs, or p38 MAPK. Knockdown of either JNK1 or JNK2 with small interfering RNA also significantly reduced the regulated PTX3 expression. Thus, lung epithelial cells appear to be a major local source for PTX3 production, which could be induced in vivo from these cells by LPS or other inflammatory stimuli, and may be an important mediator for host defense and tissue damage. The importance of the JNK pathway for the regulated PTX3 expression may be a potential target for its regulation in the lung.
authors.affiliation: Thoracic Surgery Research Laboratory, University Health Network Toronto General Research Institute, Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Bing
authors.initials: B
authors.lastname: Han
authors.forename: Marco
authors.initials: M
authors.lastname: Mura
authors.forename: Cristiano F
authors.initials: CF
authors.lastname: Andrade
authors.forename: Daisuke
authors.initials: D
authors.lastname: Okutani
authors.forename: Monika
authors.initials: M
authors.lastname: Lodyga
authors.forename: Claudia C
authors.initials: CC
authors.lastname: dos Santos
authors.forename: Shaf
authors.initials: S
authors.lastname: Keshavjee
authors.forename: Michael
authors.initials: M
authors.lastname: Matthay
authors.forename: Mingyao
authors.initials: M
authors.lastname: Liu
mesh_terms: D000818:Animals; D002097:C-Reactive Protein / Q000096:biosynthesis / Q000235:genetics*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008168:Lung / Q000166:cytology*; D051381:Rats; D020545:Respiratory Mucosa / Q000166:cytology; D000683:Serum Amyloid P-Component / Q000096:biosynthesis / Q000235:genetics*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D000099153:Pentraxins
chemical_list: D002097:C-Reactive Protein; D048031:JNK Mitogen-Activated Protein Kinases; D008070:Lipopolysaccharides; D000683:Serum Amyloid P-Component; D014409:Tumor Necrosis Factor-alpha; D000099153:Pentraxins