地塞米松通过 Toll 样受体 4-核因子-κB 通路损害小鼠树突状细胞的分化和成熟。

Dexamethasone impairs the differentiation and maturation of murine dendritic cells by Toll-like receptor 4-nuclear factor-kappaB pathway.

机构信息

Department of Immunology, School of Basic Medical Science, Capital Medical University, Beijing 100069, China.

出版信息

Chin Med J (Engl). 2010 Feb 5;123(3):344-50.

PMID:20193257

Abstract

BACKGROUND

Recent studies have demonstrated that dexamethasone (DEX) interferes with immune responses by targeting key functions of dendritic cells (DCs) at the earliest stage. However, the cellular and molecular mechanisms are still incompletely understood. This study aimed to explore the possible mechanisms by investigating the roles of DEX on differentiation, maturation & function of murine DCs and the effects of DEX on DCs via Toll-like receptor 4 (TLR4)-nuclear factor (NF)-kappaB mediated signal pathway.

METHODS

Immature DCs (imDCs) were cultured from murine bone marrow (BM) cells. We added DEX into culture medium at different time. The expression of CD11c, CD86 and I-A(b) (mouse MHC class II molecule) was determined by flow cytometry. We determined the expression of NF-kappaB and its inhibitory protein I-kappaBalpha by electrophoretic mobility shift assay (EMSA) and Western blotting, respectively. The productions of interleukin (IL)-12p70 and IL-10 in cell culture supernatants were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

DEX impaired differentiation of DCs from murine bone marrow progenitors, and inhibited lipopolysaccharide (LPS) induced maturation of DCs. DEX significantly inhibited NF-kappaB expression of normal DCs, the higher the DEX concentration or the longer the DEX treatment time, the more obvious the effect. However, DEX had little effect on LPS-induced NF-kappaB activation, and partially impaired LPS-induced I-kappaBalpha degradation. DEX significantly decreased LPS induced IL-12p70 production by DCs. Interestingly, our results showed a synergistic effect between DEX and LPS on the production of IL-10 by DCs.

CONCLUSIONS

DEX inhibits the differentiation and maturation of murine DCs involved in TLR4-I-kappaB-NF-kappaB pathway, and also indirectly impairs Th1 development and interferes with the Th1-Th2 balance through IL-12 and/or IL-10 secretion by DCs.

摘要

背景

最近的研究表明，地塞米松（DEX）通过靶向树突状细胞（DC）的早期关键功能来干扰免疫反应。然而，细胞和分子机制仍不完全清楚。本研究旨在通过研究 DEX 对小鼠 DC 分化、成熟和功能的作用，以及 DEX 通过 Toll 样受体 4（TLR4）-核因子（NF）-kappaB 介导的信号通路对 DC 的作用，来探讨可能的机制。

方法

从鼠骨髓（BM）细胞中培养未成熟的 DC（imDCs）。我们在不同时间将 DEX 添加到培养基中。通过流式细胞术测定 CD11c、CD86 和 I-A(b)（鼠 MHC Ⅱ类分子）的表达。通过电泳迁移率变动分析（EMSA）和 Western blot 分别测定 NF-kappaB 及其抑制蛋白 I-kappaBalpha 的表达。通过酶联免疫吸附试验（ELISA）测定细胞培养上清液中白细胞介素（IL）-12p70 和 IL-10 的产生。

结果

DEX 损害了鼠骨髓祖细胞来源的 DC 的分化，并抑制了 LPS 诱导的 DC 成熟。DEX 显著抑制正常 DC 的 NF-kappaB 表达，DEX 浓度越高或处理时间越长，效果越明显。然而，DEX 对 LPS 诱导的 NF-kappaB 激活影响较小，部分抑制了 LPS 诱导的 I-kappaBalpha 降解。DEX 显著降低 LPS 诱导的 DC 产生的 IL-12p70。有趣的是，我们的结果显示 DEX 和 LPS 对 DC 产生 IL-10 具有协同作用。