Role of AHR in Dendritic Cells in the Control of CNS Autoimmunity

项目总结 靶向中枢神经系统(CNS)的效应器和调节性T细胞在 多发性硬化(MS)及其实验性自身免疫性脑脊髓炎(EAE)的发病机制 树突状细胞(DC)控制着CNS特异性T细胞，但DC功能的调节途径很差 特色化的。已发表的研究表明，配体激活的转录因子芳烃具有一定的作用 受体(AHR)在DC调控中的作用。在前一个赠款周期中，我们取得了以下发现：1) 经典树突状细胞(AHRcDC)AHR表达缺失加重EAE和自身免疫T细胞 反应，2)小鼠和人类经典DC(CDCs)的单细胞rna-seq分析检测到 AHR与转录因子KLF4和胞外酶CD39的协同表达，3)AHRcDC 在CDC(KLF4cDC)中驱动KLF4的表达，KLF4cDC是一种已知限制核因子-kB激活和驱动的转录因子 巨噬细胞抗炎基因表达，4)KLF4cDC缺失加重EAE 致病T细胞反应，5)AHRcDC还促进CD39在CDC(CD39cDC)中的表达，CD39cDC降解 促炎症细胞外ATP(EATP)并参与抗炎腺苷的合成，5) CD39cDC缺失加重EAE并加剧致病T细胞应答，6)AHR激活诱导小鼠 和人类耐受性CDCs，以及7)一种新的益生菌，设计成产生AHR激动剂IAA(命名为 EcNIAA)以AHRcDC依赖的方式抑制EAE。基于这些发现，我们假设 AHRcDC驱动的KLF4和CD39在CDCs中的表达限制了CNS自身免疫。我们的具体目标是： 具体目标1：确定KLF4在AHRcDC调控CDCs中的作用。 我们建议：1)定义由AHRcDC控制的KLF4依赖和KLF4非依赖的转录程序 在单细胞和整体基因组研究中，以及2)确定KLF4在CDC中AHR调控NF-kB中的作用。 特异性目的2：确定CD39在AHRcDC调控T细胞中的作用。 我们建议：1)确定AHRcDC诱导的CD39cDC表达对髓鞘特异性T细胞的影响；2) 确定AHRcDC-CD39cDC轴是否促进调节性T细胞分化，以及3)建立作用 AHRcDC、KLF4cDC和CD39cDC在正常人和MS患者DC对T细胞调控中的作用 具体目标3：确定AHRcDC在ECNIAA抑制EAE中的作用。 该目的是评估用EcNIAA激活AHRcDC的治疗潜力，EcNIAA是一种新型益生菌，其基因工程旨在 产生AHR激动剂IAA。我们建议：1)评估ECNIAA治疗EAE的疗效；2)定义 AHRcDC和KLF4cDC在ECNIAA对DC转录调控中的作用，3)确定其贡献 AHRcDC和CD39cDC对ECNIAA调控效应T细胞的作用 总之，在这次竞争更新中，我们使用独特的工具和临床样本来研究新的方面 AHRcDC作为T细胞自身免疫的调节因子，以及作为自身免疫性疾病的治疗靶点的潜力。

PROJECT SUMMARY Effector and regulatory T cells targeting the central nervous system (CNS) play a pivotal role in the pathogenesis of multiple sclerosis (MS) and its model experimental autoimmune encephalomyelitis (EAE). Dendritic cells (DCs) control CNS-specific T cells, but the pathways regulating DC function are poorly characterized. Published studies suggest a role for the ligand-activated transcription factor aryl hydrocarbon receptor (AHR) in the control of DCs. During the previous grant cycle we have made the following findings: 1) Deletion of AHR expressed in classical DCs (AHRcDC) worsens EAE and exacerbates autoimmune T-cell responses, 2) Single-cell RNA-seq analyses of mouse and human classical DCs (cDCs) detected the coordinated expression of AHR with the transcription factor KLF4 and the ectoenzyme CD39, 3) Indeed, AHRcDC drives the expression of KLF4 in cDCs (KLF4cDC), a transcription factor known to limit NF-kB activation and drive anti-inflammatory gene expression in macrophages, 4) KLF4cDC deletion worsens EAE and exacerbates pathogenic T-cell responses, 5) AHRcDC also drives the expression of CD39 in cDCs (CD39cDC), which degrades pro-inflammatory extracellular ATP (eATP) and participates in the synthesis of anti-inflammatory adenosine, 5) CD39cDC deletion worsens EAE and exacerbates pathogenic T-cell responses, 6) AHR activation induces mouse and human tolerogenic cDCs, and 7) A novel probiotic engineered to produce the AHR agonist IAA (named EcNIAA) suppresses EAE in an AHRcDC-dependent manner. Based on these findings we hypothesize that AHRcDC-driven KLF4 and CD39 expression in cDCs limits CNS autoimmunity. Our specific aims are: Specific Aim 1: DETERMINE THE ROLE OF KLF4 IN THE CONTROL OF cDCS BY AHRcDC. We propose to: 1) Define KLF4-dependent and KLF4-independent transcriptional programs controlled by AHRcDC in single cell and bulk genomic studies, and 2) Establish the role of KLF4 in the control of NF-kB by AHR in cDCs. Specific Aim 2: ESTABLISH THE ROLE OF CD39 IN THE CONTROL OF T CELLS BY AHRcDC. We propose to: 1) Define the effects of AHRcDC-induced CD39cDC expression on myelin-specific T cells, 2) Determine whether the AHRcDC-CD39cDC axis promotes regulatory T cell differentiation, and 3) Establish the roles of AHRcDC, KLF4cDC and CD39cDC in the control of T cells by DCs in healthy controls and MS patients. Specific Aim 3: DEFINE THE ROLE OF AHRcDC IN EAE SUPPRESSION BY EcNIAA. This aim evaluates the therapeutic potential of activating AHRcDC with EcNIAA, a novel probiotic engineered to produce the AHR agonist IAA. We propose to: 1) Evaluate the therapeutic effects of EcNIAA in EAE, 2) Define the roles of AHRcDC and KLF4cDC on the transcriptional modulation of DCs by EcNIAA, 3) Establish the contribution of AHRcDC and CD39cDC to the control of effector and regulatory T cells by EcNIAA. IN SUMMARY, in this competitive renewal we use unique tools and clinical samples to study a novel aspect of AHRcDC as a regulator of T-cell autoimmunity, and its potential as a therapeutic target in autoimmune diseases.