title: Fever range temperature promotes TLR4 expression and signaling in dendritic cells.
abstract: Fever improves survival and shortens disease duration in microbial infections. However, the mechanisms of these beneficial responses still remain elusive. Toll-like receptors (TLRs) play important roles in sensing microbes invading and therefore we hypothesized that fever range temperature may enhance responsiveness of dendritic cells (DCs) to lipopolysaccharide (LPS) by promoting TLR4 expression and signaling. In this study, we found that pretreatment of DCs with 39.5 degrees C temperature can up-regulate TLR4 expression in DCs and enhances LPS-induced DC production of interleukins (IL) IL-6, IL-10 and IL-12 but not tumor necrosis factor alpha (TNF-alpha). Blockade of the autocrine action of IL-10 could increase LPS-induced TNF-alpha and IL-12 production in DCs. Further experiments confirmed that TLR4 ligation activates extracellular signal-regulated kinase (ERK), p38, and nuclear factor-kappaB pathways more potently in DCs pretreated with 39.5 degrees C. We conclude that fever range temperature can promote TLR4 expression and signaling in DCs, leading to enhancement of immune responses to inflammatory stimuli. These results might reveal a possible mechanistic explanation for the significance of fever in activating innate immune responses.
authors.affiliation: Institute of Immunology, Zhejiang University, Hangzhou 310031, China.
authors.forename: Xiaoyi
authors.initials: X
authors.lastname: Yan
authors.forename: Fangming
authors.initials: F
authors.lastname: Xiu
authors.forename: Huazhang
authors.initials: H
authors.lastname: An
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Wang
authors.forename: Jianli
authors.initials: J
authors.lastname: Wang
authors.forename: Xuetao
authors.initials: X
authors.lastname: Cao
mesh_terms: D000818:Animals; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D005260:Female; D005334:Fever / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D015870:Gene Expression / Q000187:drug effects; D016753:Interleukin-10 / Q000819:agonists; D007378:Interleukins / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000276:immunology; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism
chemical_list: D007378:Interleukins; D008070:Lipopolysaccharides; D016328:NF-kappa B; D012333:RNA, Messenger; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D016753:Interleukin-10; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases