Division of Molecular Immunology, Institute for Enzyme Research, Tokushima University, Tokushima, Japan.
Department of Pathology and Laboratory Medicine, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan.
J Immunol. 2022 Jan 15;208(2):303-320. doi: 10.4049/jimmunol.2100692. Epub 2021 Dec 20.
The deficiency of Aire, a transcriptional regulator whose defect results in the development of autoimmunity, is associated with reduced expression of tissue-restricted self-Ags (TRAs) in medullary thymic epithelial cells (mTECs). Although the mechanisms underlying Aire-dependent expression of TRAs need to be explored, the physical identification of the target(s) of Aire has been hampered by the low and promiscuous expression of TRAs. We have tackled this issue by engineering mice with augmented Aire expression. Integration of the transcriptomic data from Aire-augmented and Aire-deficient mTECs revealed that a large proportion of so-called Aire-dependent genes, including those of TRAs, may not be direct transcriptional targets downstream of Aire. Rather, Aire induces TRA expression indirectly through controlling the heterogeneity of mTECs, as revealed by single-cell analyses. In contrast, Ccl25 emerged as a canonical target of Aire, and we verified this both in vitro and in vivo. Our approach has illuminated the Aire's primary targets while distinguishing them from the secondary targets.
转录调节因子 Aire 的缺陷会导致自身免疫的发生，Aire 的缺乏与骨髓胸腺上皮细胞 (mTEC) 中组织特异性自身抗原 (TRAs) 的表达减少有关。尽管需要探索 Aire 依赖性 TRA 表达的机制，但由于 TRA 的低水平和广谱表达，Aire 的靶标的物理鉴定受到了阻碍。我们通过工程化具有增强的 Aire 表达的小鼠来解决这个问题。对增强的 Aire 和缺乏 Aire 的 mTEC 中的转录组数据进行整合，结果表明，很大一部分所谓的 Aire 依赖性基因，包括 TRA 基因，可能不是 Aire 下游的直接转录靶标。相反，通过单细胞分析揭示，Aire 通过控制 mTEC 的异质性间接诱导 TRA 表达。相比之下，Ccl25 作为 Aire 的一个典型靶标出现，我们在体外和体内都验证了这一点。我们的方法阐明了 Aire 的主要靶标，同时将它们与次要靶标区分开来。
