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Expression Profile of Human Gingival Fibroblasts Induced by Interleukin‐1β Reveals Central Role of Nuclear Factor‐Kappa B in Stabilizing Human Gingival Fibroblasts During Inflammation
Author(s) -
VardarSengul Saynur,
Arora Shilpi,
Baylas Haluk,
Mercola Dan
Publication year - 2009
Publication title -
journal of periodontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.036
H-Index - 156
eISSN - 1943-3670
pISSN - 0022-3492
DOI - 10.1902/jop.2009.080483
Subject(s) - microbiology and biotechnology , relb , inflammation , chemokine , nfkb1 , interleukin , biology , downregulation and upregulation , population , iκbα , chemistry , gene expression , cytokine , nf κb , cancer research , transcription factor , immunology , gene , medicine , biochemistry , environmental health
Background: Interleukin (IL)‐1β is a key cytokine in the pathogenesis of periodontitis, and it induces inflammatory mediators in periodontal diseases. We developed immortalized human gingival fibroblasts (HGFs), investigated the effects of IL‐1β on the gene expression using expression arrays containing ∼40,000 genes, and tested the role of nuclear factor‐kappa B (NF‐κB) in maintaining an activated HGF population. Methods: Total RNA was isolated from IL‐1β–induced and mock‐induced control cells. Gene expression analyses were performed using expression arrays and confirmed by quantitative real‐time polymerase chain reaction. Western blot analysis to show inhibitor of kappa B‐alpha (IκBα) phosphorylation and immunostaining of cells for NF‐κB nuclear translocation were performed. Apoptosis was confirmed by assay of poly ADP‐ribose polymerase (PARP) cleavage. Results: A total of 382 probe sets corresponding to 254 genes were differentially expressed in IL‐1β–induced cells ( P <0.001). A total of 215 genes were upregulated, and 39 genes were downregulated. Most notable NF‐κB pathway members (NFκB1, NFκB2, IκBα, IκB∊, IκBζ, REL, RELB, and TA‐NFKBH) were upregulated. IκBα was phosphorylated, and NF‐κB accumulated in the nucleus. An IL‐1β–induced set of 27 genes was downregulated by an NF‐κB inhibitor, leading to a decreased number of viable cells and suggesting an antiapoptotic role for NF‐κB. Conclusions: IL‐1β leads to a large number of significant expression changes consistent with a pathologic role in periodontitis, including enhancement of inflammatory cytokines, chemokines, transcription factors, matrix metalloproteinases, adhesion molecules, and especially NF‐κB–dependent antiapoptotic genes. NF‐κB activation blocks apoptosis, thereby stabilizing the HGF population in inflammation.