Fenoterol, a β2-adrenoceptor agonist, inhibits LPS- induced membrane-bound CD14, TLR4/CD14 complex, and inflammatory cytokines production through β-arrestin-2 in THP-1 cell line  

作　　者：Wei WANG Ming XU You-yi ZHANG Bei HE 

机构地区：[1]Department of Respiratory Medicine, Peking University Third Hospital, Beijing 100191, China [2]Institute of Vascular Medicine, Peking University Third Hospital, and Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing 100191, China

出　　处：《Acta Pharmacologica Sinica》2009年第11期1522-1528,共7页中国药理学报（英文版）

基　　金：Acknowledgements Project was supported by the National Key Basic Research Program （NKBRP） of People＇s Republic of China （No 2006CB503806） and the National Natural Science Foundation of China （No 30770939 and 30821001）. The authors would like to thank Dr Laura HERATY for language revision, and Dr Pei ZHANG for performing the confocal laser scanning microscope.

摘　　要：Aim To investigate the molecular mechanism and signaling pathway by which fenoterol, a β2-adrenergic receptor （β2-AR） agonist, produces anti-inflammatory effects. Methods： THP-1, a monocytic cell line, was used to explore the mechanism of β2-AR stimulation in LPS-induced secretion of inflammatory cytokines and changes of toll-like receptors （TLRs）. We labeled TLR4 and CD14 using monoclonal anti-TLR4 PE-conjugated and anti-CD14 FITC-conjugated antibodies in THP-1 cells stimulated by β2-AR in the presence or absence of lipopolysaccharide （LPS） and small, interfering RNA （siRNA）-mediated knockdown of β-arrestin-2, and then analyzed their changes in distribution by flow cytometry, Western blotting and confocal analysis. Results： LPS-induced membrane-bound CD14, TLR4/CD14 complex levels and elevation of inflammatory cytokines were all significantly reduced by pre-incubation of fenoterol （P〈0.05）. However, the total level of CD14 and TLR4 was not significantly changed. Interestingly, confocal microscopy revealed redistribution of CD14 and TLR4/CD14 complex under β2-AR stimulation. Furthermore, siRNAmediated knockdown of β-arrestin-2 eliminated the anti-inflammatory effects and redistribution of CD14 and TLR4/CD14 complex stimulated by β2-AR. Conclusion： β2-AR agonist exerts its anti-inflammatory effects by down-regulating TLR signaling in THP-1 cells, potentially resulting from β-arrestin-2 mediated redistribution of CD14 and TLR14/CD14 complex.Aim To investigate the molecular mechanism and signaling pathway by which fenoterol, a β2-adrenergic receptor （β2-AR） agonist, produces anti-inflammatory effects. Methods： THP-1, a monocytic cell line, was used to explore the mechanism of β2-AR stimulation in LPS-induced secretion of inflammatory cytokines and changes of toll-like receptors （TLRs）. We labeled TLR4 and CD14 using monoclonal anti-TLR4 PE-conjugated and anti-CD14 FITC-conjugated antibodies in THP-1 cells stimulated by β2-AR in the presence or absence of lipopolysaccharide （LPS） and small, interfering RNA （siRNA）-mediated knockdown of β-arrestin-2, and then analyzed their changes in distribution by flow cytometry, Western blotting and confocal analysis. Results： LPS-induced membrane-bound CD14, TLR4/CD14 complex levels and elevation of inflammatory cytokines were all significantly reduced by pre-incubation of fenoterol （P〈0.05）. However, the total level of CD14 and TLR4 was not significantly changed. Interestingly, confocal microscopy revealed redistribution of CD14 and TLR4/CD14 complex under β2-AR stimulation. Furthermore, siRNAmediated knockdown of β-arrestin-2 eliminated the anti-inflammatory effects and redistribution of CD14 and TLR4/CD14 complex stimulated by β2-AR. Conclusion： β2-AR agonist exerts its anti-inflammatory effects by down-regulating TLR signaling in THP-1 cells, potentially resulting from β-arrestin-2 mediated redistribution of CD14 and TLR14/CD14 complex.

关 键 词：β2-adrenoceptor toll-like receptors β-arrestin-2 FENOTEROL confocal microscopy lipopolysaccharide 

分 类 号：Q78[生物学—分子生物学] S859.79[农业科学—临床兽医学]