RelB as a master regulator of the thymic medulla: characterization of factors that control RelB expression and the role of the RelB target gene Enpp2/Atx

RelB 作为胸腺髓质的主调节因子：控制 RelB 表达的因子的特征以及 RelB 靶基因 Enpp2/Atx 的作用

• 批准号: 154810081
• 负责人: Professor Dr. Christoph Englert, since 11/2014
• 金额: --
• 依托单位: Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/154810081?language=en
• 关键词: RelB; master; regulator; thymic; medulla

In the previous funding period, we showed that mice with a thymic epithelial cell (TEC)-specific ablation of the NF-kB family member RelB (RelbTEC-KO) lacked all medullary mTECs resulting in autoimmunity. Surprisingly, the RelbTEC-KO autoimmune pathology was very mild compared to Relb-null mice with respect to both severity of inflammatory infiltrates and number of affected organs. Notably, RelaTEC-KO mice had only a partial loss of mTECs and did not develop autoimmunity. Rescue experiments showed that the RelaTEC-KO phenotype was largely due to decreased expression of RelB, which regulated mTEC numbers in a dose-dependent manner. Our results indicate that RelB drives commitment of bipotent TEC precursors to the mTEC lineage.To investigate whether other components of the classical NF-kB signaling pathway regulate RelB levels in mTECs we will initially focus on c-Rel, which cooperates in vitro with RelA in the induction of RelB expression. In addition, we will investigate whether the TNF receptor-associated factor TRAF6 is upstream of RelB. The role of RelB in early mTEC development will be addressed using the newly generated Relb-Cre-P2A-Katushka reporter mouse line. These mice enable us to purify RelB-positive and RelB-negative mTECs by flow cytometry for transcriptome analyses and the identification of novel RelB target genes. Since the severity of autoimmunity correlated with markedly increased atrophy of the thymic medulla in RelB-null compared to RelbTEC-KO mice, we will furthermore investigate the role of RelB in development and function of non-TECs, such as mesenchymal and endothelial cells. In particular, we want to find out the cellular origin and function of the secreted enzyme autotaxin, which is expressed in the thymus by non-TECs in a RelB-dependent manner.

在之前的资助期内，我们发现胸腺上皮细胞（TEC）特异性消融NF-kB家族成员RelB （RelbTEC-KO）的小鼠缺乏所有髓质mtec，导致自身免疫。令人惊讶的是，与Relb-null小鼠相比，在炎症浸润的严重程度和受影响器官的数量方面，RelbTEC-KO自身免疫病理非常轻微。值得注意的是，RelaTEC-KO小鼠仅部分丢失mtec，未发生自身免疫。援救实验表明，RelaTEC-KO表型主要是由于RelB的表达减少，RelB以剂量依赖的方式调节mTEC数量。我们的研究结果表明，RelB驱动双能TEC前体向mTEC谱系的转移。为了研究经典NF-kB信号通路的其他成分是否调节mtec中RelB的水平，我们将首先关注c-Rel，它在体外与RelA合作诱导RelB的表达。此外，我们将研究TNF受体相关因子TRAF6是否位于RelB的上游。RelB在早期mTEC发展中的作用将通过新生成的RelB - cre - p2a - katushka报告小鼠系来解决。这些小鼠使我们能够通过流式细胞术纯化RelB阳性和RelB阴性的mtec，用于转录组分析和鉴定新的RelB靶基因。由于与RelbTEC-KO小鼠相比，RelB-null小鼠自身免疫的严重程度与胸腺髓质的萎缩明显增加相关，因此我们将进一步研究RelB在非tec细胞（如间充质细胞和内皮细胞）的发育和功能中的作用。特别是，我们想要找出分泌酶autotaxin的细胞起源和功能，该酶在胸腺中由非tec以relb依赖的方式表达。

项目成果

The deubiquitinating enzyme CYLD regulates the differentiation and maturation of thymic medullary epithelial cells

• DOI: 10.1038/icb.2014.122
• 发表时间: 2015-07
• 期刊: Immunology and Cell Biology
• 影响因子: 4
• 作者: S. Reissig;N. Hövelmeyer;Yilang Tang;Debra S. Weih;Alexey Nikolaev;M. Riemann;F. Weih;A. Waisman