Indoleamine 2,3-dioxygenase tissue distribution and cellular localization in mice: implications for its biological functions.
Indoleamine 2,3-dioxygenase tissue distribution and cellular localization in mice: implications for its biological functions.
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DOI：
10.1369/jhc.2009.953604
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发表时间：
2010-01-01
期刊：
影响因子：
--
通讯作者：
Zhu, Bao Ting
中科院分区：
文献类型：
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作者：
Dai, Xiangchen;Zhu, Bao Ting
早期的研究表明吲哚胺2，3-双加氧酶（IDO）在哺乳动物中具有广泛的组织分布。然而，关于其细胞定位以及在各种组织中的表达水平的详细信息仍然很少。在本研究中，我们试图确定IDO的细胞定位，并通过使用分支DNA信号放大分析，Western印迹和免疫组织化学染色来量化其在各种小鼠组织中的表达水平。最高水平的组成性IDO表达被发现是选择性地存在于附睾的头部，除了其初始段。IDO的表达也检测到内部的腔室，甚至在该区域内的静纤毛。在前列腺中，高水平的IDO选择性地表达在囊细胞中。此外，在胎盘、脾、胸腺、肺和消化道中的某些类型的细胞中也选择性地检测到高水平的IDO表达。值得注意的是，这些器官中大多数阳性染色细胞的形态特征与抗原呈递细胞的形态特征非常相似。基于IDO的组织分布和细胞定位特征，假设其表达可能具有两个主要功能：一种是在封闭的微环境中耗尽色氨酸（如在附睾管腔中）以防止细菌或病毒感染，另一种是产生生物活性色氨酸催化剂，其将用于抑制T细胞介导的针对自身抗原，胎儿抗原，或同种异体抗原。
Earlier studies have suggested that indoleamine 2,3-dioxygenase (IDO) has a wide tissue distribution in mammals. However, detailed information on its cellular localization and also the levels of expression in various tissues is still scarce. In the present study, we sought to determine the cellular localization of IDO and also to quantify the level of its expression in various mouse tissues by using the branched DNA signal amplification assay, Western blotting, and immunohistochemical staining. The highest levels of constitutive IDO expression were found to be selectively present in the caput of epididymis, except for its initial segment. IDO expression was also detected inside the luminal compartment and even in the stereocilia within this region. In the prostate, high levels of IDO were selectively expressed in the capsular cells. In addition, high levels of IDO expression were also selectively detected in certain types of cells in the placenta, spleen, thymus, lung, and digestive tract. Notably, the morphological features of most of the positively stained cells in these organs closely resembled those of antigen-presenting cells. Based on the tissue distribution and cellular localization characteristics of IDO, it is hypothesized that its expression may serve two main functions: one is to deplete tryptophan in an enclosed microenvironment (such as in the epididymal duct lumen) to prevent bacterial or viral infection, and the other is to produce bioactive tryptophan catabolites that would serve to suppress T-cell-mediated immune responses against self-antigens, fetal antigens, or allogeneic antigens, in different situations.