Intracellular mammalian DNA stimulates myeloid dendritic cells to produce type I interferons predominantly through a Toll-like receptor 9-independent pathway
Intracellular mammalian DNA stimulates myeloid dendritic cells to produce type I interferons predominantly through a Toll-like receptor 9-independent pathway
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DOI：
10.1002/art.21677
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发表时间：
2006-03-01
影响因子：
--
通讯作者：
Elkon, KB
中科院分区：
文献类型：
--
作者：
Martin, DA;Elkon, KB
目标。外源核酸，包括细菌非甲基化DNA和病毒单链RNA，通过与Toll样受体(TLRs)相互作用，是天然免疫的有效激活剂。相比之下，哺乳动物的DNA通常被认为对先天免疫有有限的激活作用，甚至是抑制作用。由于DNA是死亡细胞的主要成分，而且最近的研究表明哺乳动物的核酸在某些条件下可能具有刺激性，因此我们开展了这项研究，以检测细胞内哺乳动物DNA对髓系树突状细胞(DC)激活的影响。将哺乳动物DNA导入小鼠骨髓来源的DC(BMDCs)。流式细胞仪(CD40、CD86)检测BMDC活性。用酶联免疫吸附试验检测肿瘤坏死因子a和白细胞介素6的产生，用生物法测定I型干扰素(IFN)的产生。以髓系分化缺陷小鼠的骨髓基质细胞(MyD88)、TLR-9和干扰素α/β受体缺陷的小鼠为研究对象进行平行研究。细胞内哺乳动物DNA激活未成熟的BMDCs，这是由CD40和CD86的上调以及大量I型干扰素的产生所确定的。干扰反应相对独立于TLR-9和TLR接头MyD88。缺乏干扰素α/β受体的BMDCs对细胞内DNA的干扰素应答降低，而缺乏蛋白激酶R的胚胎成纤维细胞对细胞内DNA的干扰素应答无明显变化。这些结果表明，细胞内DNA主要通过TLR非依赖的途径刺激BMDC成熟和干扰素的产生，并支持这样一种模型，即内源性DNA的低效清除和/或降解可能刺激类似于TLR非依赖的外源(即病毒)双链RNA的先天免疫反应。
Objective. Exogenous nucleic acids, including bacterial unmethylated DNA and viral single-stranded RNA, are potent activators of innate immunity through interaction with the Toll-like receptors (TLRs). In contrast, mammalian DNA has been generally thought to have a limited activation effect, or even a suppressive effect, on innate immunity. Since DNA is a major component of dying cells and recent studies indicate that mammalian nucleic acids may be stimulatory under certain conditions, we undertook this study to examine the effect of intracellular mammalian DNA on myeloid dendritic cell (DC) activation.Methods. Mammalian DNA was introduced into murine bone marrow-derived DCs (BMDCs) by transfection. BMDC activation was determined by flow cytometry (CD40, CD86). Production of tumor necrosis factor a and interleukin-6 was measured by enzyme-linked immunosorbent assay, and production of type I interferons (IFNs) by bioassay. Parallel studies were conducted using BMDCs from mice deficient in myeloid differentiation 88 (MyD88), TLR-9, and IFN alpha/beta receptor.Results. Intracellular mammalian DNA activated immature BMDCs, as determined by the up-regulation of CD40 and CD86 as well as by the production of significant quantities of type I IFN. The interferogenic response was shown to be relatively independent of TLR-9, and the TLR adaptor MyD88. The IFN response to intracellular DNA was reduced in BMDCs lacking IFN alpha/beta receptor but was intact in embryonic fibroblasts lacking protein kinase R.Conclusion. These results indicate that intracellular DNA stimulates BMDC maturation and IFN production predominantly through a TLR-independent pathway, and support a model whereby inefficient clearance and/or degradation of endogenous DNA may stimulate innate immune responses similar to the TLR-independent response to exogenous (i.e., viral) double-stranded RNA.