Kont Vivian, Laan Martti, Kisand Kai, Merits Andres, Scott Hamish S, Peterson Pärt
Molecular Pathology, Biomedicum, Tartu University, Ravila 19, 50411 Tartu, Estonia.
Mol Immunol. 2008 Jan;45(1):25-33. doi: 10.1016/j.molimm.2007.05.014. Epub 2007 Jun 28.
Intrathymic expression of tissue-restricted antigens (TRAs) has been viewed as the key element in the induction of central tolerance and recently, a central role for the autoimmune regulator (Aire) has been suggested in this process. The aim of this study was to establish whether down or up-regulation of Aire leads to alterations in TRA expression and whether this is limited to thymic epithelial cells. This study also characterized whether TRAs follow Aire expression during normal development, and whether thymic microenvironment plays a role in the expression of Aire and TRAs. We did several in vivo and in vitro experiments to manipulate Aire expression and measured expression of four TRAs (Trefoil factor-3, Insulin-2, Major urinary protein-1 and Salivary protein-1) by real-time RT-PCR. Aire had an allele dose-dependent effect on TRA expression in the thymuses of mice from two strains, C57BL/6J and Balb/c, but had no effect on TRA expression in the lymph nodes. In the thymus, Aire and TRAs were both localized in the medulla and were co-expressed during normal development and involution. In the primary stromal cells as well as thymic epithelial cell line, the adenoviral over-expression of Aire resulted in an increase in TRA expression. By manipulating in vitro organ-cultures we showed that thymic microenvironment plays a dominant role in Aire expression whereas TRAs follow the same pattern. The data underline a direct role for Aire in TRA expression and suggest that modulation of Aire has a potential to control central tolerance and autoimmunity.
组织限制性抗原（TRA）的胸腺内表达被视为诱导中枢耐受的关键因素，最近有研究表明自身免疫调节因子（Aire）在此过程中发挥核心作用。本研究的目的是确定Aire的下调或上调是否会导致TRA表达的改变，以及这种改变是否仅限于胸腺上皮细胞。本研究还对正常发育过程中TRA是否跟随Aire表达，以及胸腺微环境在Aire和TRA表达中是否起作用进行了表征。我们进行了多项体内和体外实验来调控Aire的表达，并通过实时逆转录聚合酶链反应（RT-PCR）检测了四种TRA（三叶因子-3、胰岛素-2、主要尿蛋白-1和唾液蛋白-1）的表达。Aire对两种品系（C57BL/6J和Balb/c）小鼠胸腺中的TRA表达具有等位基因剂量依赖性效应，但对淋巴结中的TRA表达没有影响。在胸腺中，Aire和TRA均定位于髓质，并且在正常发育和退化过程中共同表达。在原代基质细胞以及胸腺上皮细胞系中，Aire的腺病毒过表达导致TRA表达增加。通过体外器官培养实验，我们发现胸腺微环境在Aire表达中起主导作用，而TRA遵循相同模式。这些数据强调了Aire在TRA表达中的直接作用，并表明调节Aire有可能控制中枢耐受和自身免疫。
