Retinoic acid-inducible gene-I is induced in gingival fibroblasts by lipopolysaccharide or poly IC: possible roles in interleukin-1beta, -6 and -8 expression.
Retinoic acid-inducible gene-I (RIG-I) is a member of the DExH family of proteins, and little is known of its biological function in the oral region. We previously reported that interleukin 1beta (IL-1beta) induced RIG-I expression in gingival fibroblasts. In this study, we studied the mechanism of RIG-I expression induced by lipopolysaccharide (LPS) or double-stranded RNA (dsRNA) in gingival fibroblasts. We also addressed the role of RIG-I in the expression of IL-1beta, IL-6 and IL-8 in gingival fibroblasts stimulated with LPS or dsRNA. We stimulated cultured human gingival fibroblasts with LPS or dsRNA, and examined the expression of RIG-I mRNA and protein. The effect of cycloheximide, a protein synthesis inhibitor, on RIG-I induction by these stimuli was examined. The expression of IL-1beta, IL-6 and IL-8 in gingival fibroblasts transfected with RIG-I cDNA stimulated with LPS or dsRNA was examined. LPS or dsRNA induced the expression of mRNA and protein for RIG-I in concentration- and time-dependent manners. We also examined the localization of RIG-I, and found that it was expressed in cytoplasm. Cycloheximide did not suppress the LPS or dsRNA-induced RIG-I expression. Introduction of RIG-I cDNA into gingival fibroblasts resulted in enhanced expression of IL-1beta, IL-6 and IL-8; moreover, overexpression of RIG-I stimulated with LPS or dsRNA synergistically increased expression of IL-1beta, IL-6 and IL-8. RIG-I may have important roles in the innate immune response in the regulation of IL-1beta, IL-6 and IL-8 expression in gingival fibroblasts in response to LPS and dsRNA.
Kubota
K
K
Department of Dentistry and Oral Surgery, Hirosaki University School of Medicine, Hirosaki, Japan. kouseik@par.odn.ne.jp
Sakaki
H
H
Imaizumi
T
T
Nakagawa
H
H
Kusumi
A
A
Kobayashi
W
W
Satoh
K
K
Kimura
H
H
D015153:Blotting, Western; D003513:Cycloheximide / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli; D005347:Fibroblasts / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D005881:Gingiva / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D053583:Interleukin-1beta / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D016209:Interleukin-8 / Q000096:biosynthesis; D007378:Interleukins / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000378:metabolism; D011070:Poly I-C / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000502:physiology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012330:RNA, Double-Stranded / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology*; D014162:Transfection
D053583:Interleukin-1beta; D015850:Interleukin-6; D016209:Interleukin-8; D007378:Interleukins; D008070:Lipopolysaccharides; D011135:Polysaccharides, Bacterial; D011500:Protein Synthesis Inhibitors; C431552:RAI1 protein, human; D012330:RNA, Double-Stranded; D015534:Trans-Activators; D014157:Transcription Factors; D003513:Cycloheximide; D011070:Poly I-C