Overexpressing autoimmune regulator regulates the expression of toll-like receptors by interacting with their promoters in RAW264.7 cells
Overexpressing autoimmune regulator regulates the expression of toll-like receptors by interacting with their promoters in RAW264.7 cells
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过度表达的自身免疫调节因子通过与 RAW264.7 细胞中的启动子相互作用来调节 Toll 样受体的表达。
DOI：
10.1016/j.cellimm.2011.05.002
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发表时间：
2011-01-01
影响因子：
4.3
通讯作者：
Li, Yi
中科院分区：
文献类型：
--
作者：
Zhu, Wufei;Yang, Wei;Li, Yi
自身免疫调节因子（Autoimmune regulator，Aire）是一种转录激活因子，调节胸腺髓质上皮细胞中多种组织限制性抗原的异位表达，在自身反应性T细胞的负选择中起重要作用。然而，Aire表达在外周淋巴组织和造血细胞，特别是单核细胞/巨噬细胞中的作用仍然知之甚少。在本研究中，我们发现在稳定表达Aire的小鼠巨噬细胞样细胞系（RAW264.7）中，Toll样受体（TLR）1、TLR 3和TLR 8的mRNA和蛋白表达水平显著上调，而TLR 2、TLR 4、TLR 5、TLR 6、TLR 7和TLR 9的表达没有显著变化。此外，瞬时转染Aire的原代腹腔巨噬细胞TLR 3和TLR 8的mRNA表达显著增加。使用染色质免疫沉淀和荧光素酶活性测定，我们还发现，Aire与TLR 1，TLR 3和TLR 8启动子相互作用，并增加这些启动子在RAW 264. 7细胞中的荧光素酶转录活性。此外，在用Pam（3）CSK（4）（一种TLR 1配体）和poly（I：C）（一种TLR 3配体）刺激后，我们发现在稳定表达Aire的RAW264.7细胞中，IL-TNF α、iNOS和IFN α的mRNA表达水平增加。总之，这些数据表明，Aire通过调节TLR的表达在抗原呈递细胞（APC）中识别病原微生物和外周免疫耐受中具有至关重要的作用。(C)2011 Elsevier Inc. All rights reserved.
Autoimmune regulator (Aire) is a transcriptional activator that regulates the ectopic expression of many tissue-restricted antigens in medullary thymic epithelial cells, and that has an important role in the negative selection of autoreactive T cells. However, the roles of Aire expression in peripheral lymphoid tissues and hematopoietic cells, especially monocytes/macrophages, remain poorly understood. In this study, we found that the mRNA and protein expression levels of toll-like receptor (TLR)1, TLR3, and TLR8 were notably up-regulated in a mouse macrophage-like cell line (RAW264.7) stably expressing Aire, while the expression of TLR2, TLR4, TLR5, TLR6, TLR7, and TLR9 were not significantly changed. In addition, the mRNA expression of TLR3 and TLR8 were significantly increased in primary peritoneal macrophages transiently transfected with Aire. Using chromatin immunoprecipitation and a luciferase activity assay, we also found that Aire interacted with the TLR1, TLR3, and TLR8 promoters and increased the luciferase transcriptional activity of these promoters in RAW264.7 cells. Moreover, after stimulation by Pam(3)CSK(4), a TLR1 ligand, and poly(I:C), a TLR3 ligand, we found that the mRNA expression levels of IL-TNF alpha, iNOS, and IFN alpha were increased in RAW264.7 cells stably expressing Aire. Together, these data suggest that Aire has a crucial role in the recognition of pathogenic microorganisms and peripheral immune tolerance in antigen-presenting cells (APCs) by regulating the expression of TLRs. (C) 2011 Elsevier Inc. All rights reserved.