Human gingival CD14(+) fibroblasts primed with gamma interferon increase production of interleukin-8 in response to lipopolysaccharide through up-regulation of membrane CD14 and MyD88 mRNA expression.
Gamma interferon (IFN-gamma)-primed human gingival fibroblasts (HGF) have been shown to produce higher levels of interleukin-8 (IL-8) upon stimulation with bacterial products and inflammatory cytokines than nonprimed controls. In this study, we examined whether priming of HGF with IFN-gamma up-regulates IL-8 production by the cells in response to purified lipopolysaccharide (LPS). The priming effect of IFN-gamma was clearly observed in the high-CD14-expressing (CD14(high)) HGF but not in the low-CD14-expressing (CD14(low)) HGF. The CD14(high) HGF were most effectively primed with IFN-gamma (1,000 IU/ml) for 72 h. To elucidate the mechanism of the priming effects of IFN-gamma for the LPS response by HGF, we examined whether IFN-gamma regulated expression of CD14, Toll-like receptor 2 (TLR2), TLR4, MD-2, and MyD88, all of which are molecules suggested to be associated with LPS signaling. In CD14(high) HGF, IFN-gamma markedly up-regulated CD14 and MyD88 but not TLR4 protein and MD-2 mRNA expression, while in CD14(low) HGF, IFN-gamma slightly increased MyD88 and scarcely affected CD14, TLR4 protein, and MD-2 mRNA levels. LPS-induced IL-8 production by IFN-gamma-primed CD14(high) HGF was significantly inhibited by monoclonal antibodies (MAbs) against CD14 and TLR4, but not by an anti-TLR2 MAb. These findings suggested that IFN-gamma primed CD14(high) HGF to enhance production of IL-8 in response to LPS through augmentation of the CD14-TLR system, where the presence of membrane CD14 was indispensable for the response of HGF to LPS.
Tamai
Riyoko
R
Department of Microbiology and Immunology, Tohoku University School of Dentistry, Sendai 980-8575, Japan.
Sakuta
Tetsuya
T
Matsushita
Kenji
K
Torii
Mitsuo
M
Takeuchi
Osamu
O
Akira
Shizuo
S
Akashi
Sachiko
S
Espevik
Terje
T
Sugawara
Shunji
S
Takada
Haruhiko
H
D048868:Adaptor Proteins, Signal Transducing; D000293:Adolescent; D000943:Antigens, Differentiation / Q000096:biosynthesis*; D002648:Child; D029721:Drosophila Proteins; D005881:Gingiva / Q000166:cytology / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D016209:Interleukin-8 / Q000096:biosynthesis*; D018950:Lipopolysaccharide Receptors / Q000096:biosynthesis* / Q000187:drug effects / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D053594:Myeloid Differentiation Factor 88; D012333:RNA, Messenger / Q000096:biosynthesis; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D011971:Receptors, Immunologic / Q000096:biosynthesis*; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D015854:Up-Regulation
D048868:Adaptor Proteins, Signal Transducing; D000943:Antigens, Differentiation; D029721:Drosophila Proteins; D016209:Interleukin-8; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; C507779:MYD88 protein, human; D008562:Membrane Glycoproteins; D053594:Myeloid Differentiation Factor 88; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D007371:Interferon-gamma