Role of aryl hydrocarbon receptor in IL-10 producing Tr1 regulatory cells

 描述（由申请人提供）：产生IL-10的1型调节性T细胞（Tr 1细胞）在免疫调节中发挥重要作用;因此，Tr 1细胞诱导和扩增是治疗免疫介导疾病的潜在方法。然而，控制Tr 1细胞分化和功能的机制在很大程度上是未知的。在我们之前的资助周期中，我们发现转录因子AHR控制Tr 1细胞分化。此外，我们最近发现， IL-27和AHR控制Tr 1细胞和树突状细胞（DCs）中外核苷酸酶CD 39的表达。CD 39将促炎性细胞外三磷酸腺苷（eATP）降解为腺苷一磷酸（AMP）;然后AMP被外-5 '-核苷酸酶CD 73用于合成免疫抑制性腺苷。我们的初步数据表明，缺氧和eATP（两者都在炎症组织中检测到）以HIF 1 α依赖性方式抑制Tr 1细胞分化。此外，初步实验表明，CD 39通过与应答T细胞（Tresp）和DC表达的CD 73合作产生腺苷，独立于IL-10而有助于Tr 1细胞的抑制活性。基于这些观察结果，我们假设AHR/CD 39和eATP/HIF 1 α激活之间的平衡控制Tr 1细胞的分化、稳定性和功能。我们的具体目标是：具体目标1：AHR/CD 39和eATP/HIF 1 α激活如何控制Tr 1细胞分化？我们的初步数据表明，eATP和缺氧（炎症组织的代谢特征）通过转录因子HIF 1 α介导的机制抑制AHR来抑制Tr 1细胞分化。因此，我们建议：1）检查CD 39在限制eATP对Tr 1细胞分化的抑制作用中的作用。2)分析eATP和缺氧对AHR信号通路和Tr 1细胞分化的影响，以及HIF 1 α在其中的作用。3)研究eATP的作用 缺氧对Tr 1细胞转录程序的影响。具体目标2：Tr 1细胞表达的CD 39如何有助于其抑制功能？我们的初步数据表明，CD 39参与了Tr 1细胞的抑制功能。因此，我们拟：1）研究CD 39在Tr 1抑制活性中的作用。2)分析eATP耗竭对Tr 1细胞稳定性和功能的影响。3)检查Tresp中CD 73产生的腺苷与Tr 1细胞表达的CD 39协同作用对其抑制功能的贡献。具体目标3：DC对Tr 1细胞分化和功能有何作用？DC中的IL-27信号传导以CD 39依赖性方式限制炎症。我们的初步数据表明，DC中的CD 39和CD 73控制Tr 1细胞的分化和功能。因此，我们拟：1）研究DC表达的CD 39对Tr 1细胞生成和稳定性的影响。2)分析DC中CD 39和CD 73在Tr 1抑制功能中的作用。总之，该项目研究了Tr 1细胞分化的阳性（AHR/CD 39）和阴性（eATP/HIF 1 α）调节剂、它们的生理作用及其对Tr 1细胞治疗调节的潜在价值。

 DESCRIPTION (provided by applicant): IL-10 producing type 1 regulatory T cells (Tr1 cells) play an important role in immune regulation; thus, Tr1 cell induction and expansion are potential approaches to treat immune-mediated disorders. However, the mechanisms controlling Tr1 cell differentiation and function are largely unknown. During our previous funding cycle we found that the transcription factor AHR controls Tr1 cell differentiation. In addition, we recently found that IL-27 and AHR control the expression of the ectonucleotidase CD39 in Tr1 cells and dendritic cells (DCs). CD39 degrades pro-inflammatory extracellular adenosine triphosphate (eATP) into adenosine monophosphate (AMP); AMP is then used by the ecto-5'-nucleotidase CD73 to synthesize immunosuppressive adenosine. Our preliminary data suggest that hypoxia and eATP (both of which are detected in inflamed tissues) suppress Tr1 cell differentiation in a HIF1α-dependent manner. Moreover, preliminary experiments suggest that CD39 contributes to the suppressive activity of Tr1 cells independently of IL-10, through the production of adenosine in cooperation with CD73 expressed by responder T cells (Tresp) and DCs. Based on these observations, we hypothesize that the balance between AHR/CD39 and eATP/HIF1α activation controls Tr1 cell differentiation, stability and function. Our specific aims are: Specific Aim 1: Hw does AHR/CD39 and eATP/HIF1α activation control Tr1 cell differentiation? Our preliminary data suggest that eATP and hypoxia (metabolic features of inflamed tissues) suppress Tr1 cell differentiation by inhibiting AHR through a mechanism mediated by the transcription factor HIF1α. Thus, we propose to: 1) Examine the role of CD39 on limiting the inhibitory effects of eATP on Tr1 cell differentiation. 2) Analyze the effects of eATP and hypoxia on AHR signaling and Tr1 cell differentiation, and the role of HIF1α in these effects. 3) Study the effects of eATP and hypoxia on the transcriptional program of Tr1 cells. Specific Aim 2: How does CD39 expressed by Tr1 cells contribute to their suppressive function? Our preliminary data suggest that CD39 participates in the suppressive function of Tr1 cells. Thus, we propose to: 1) Study the function of CD39 on Tr1 suppressive activity. 2) Analyze the effects of eATP depletion on Tr1 cell stability and function. 3) Examine the contribution of adenosine generated by CD73 in Tresp in cooperation with CD39 expressed by Tr1 cells on their suppressive function. Specific Aim 3: What is the role of DCs on Tr1 cell differentiation and function? IL-27 signaling in DCs limits inflammation in a CD39-dependent manner. Our preliminary data suggest that CD39 and CD73 in DCs control Tr1 cell differentiation and function. Thus, we propose to: 1) Study the role of CD39 expressed by DCs on Tr1 cell generation and stability. 2) Analyze the role of CD39 and CD73 in DCs on Tr1 suppressive function. In summary, this project studies positive (AHR/CD39) and negative (eATP/HIF1α) regulators of Tr1 cell differentiation, their physiological roles and their potential value for the therapeutic modulation of Tr1 cells.