Modeling and Analysis of the Role of Microbiota Metabolites in T-Cell Differentiation

 描述（由申请人提供）：调节性T细胞（T细胞）包括一种异质性淋巴细胞，其能够通过细胞因子分泌和树突状细胞功能的调节促进外周组织中的免疫耐受。目前存在的方法是在TGF-β（诱导的或iTGF β）存在下体外选择性扩增TGF β，并转移至患者，用于治疗性抑制患有炎性肠病、移植物抗宿主病和以过度炎症为特征的其他病理的患者的炎症。虽然iTdR的过继转移有希望在临床上是安全的，但在这种治疗策略的转化中仍然存在主要障碍。比如说 转移到患有急性或慢性炎症的患者体内的iTHBE可以从抗 在微环境中存在的炎性细胞因子的影响下，炎症性iTreg表型转化为促炎性Th 17表型，从而对炎症状态有负面影响。因此，重要的是产生当引入炎症微环境中时具有稳定的调节表型和功能的iT细胞。几项研究将体内Treg发育与肠道中丰富多样的微生物群（微生物群）的存在联系起来。虽然微生物群在生理免疫耐受中的作用知之甚少，但普遍的假设是微生物群产生促进Treg诱导并将肠道免疫调节至耐受状态的特定因子。我们以前证明，吲哚，一种来自饮食色氨酸的微生物群代谢物，存在于健康小鼠和人类的胃肠道中，可以减弱炎症指标。来自我们实验室的未发表数据也表明，在吲哚和iTreg-偏斜条件存在下体外调节后，CD 4 + CD 25- naïve T细胞显著扩增为Foxp 3 + iTreg。然而，iTreg的稳定性和功能可以通过几种促炎和抗炎细胞因子协同增加或减弱，因此，系统预测微生物群代谢物调节Treg稳定性和炎症环境中功能的关系的能力将有助于我们理解Treg免疫生物学和推进基于Treg细胞的治疗。我们的总体假设是色氨酸衍生的微生物群代谢物（TDMM）诱导具有增强的体内稳定性的Treg表型。使用来自暴露于不同色氨酸衍生的微生物群代谢物的Treg和Th 17数据，我们建议开发用于在吲哚存在下体外Treg诱导和体内转移后稳定性的神经网络模型，并使用该模型生成关于最佳Treg诱导、功能和稳定性的可测试预测。具体 目标是：（1）：全面确定TDMM诱导的iTreg和Th 17细胞的体外表型和功能;（2）：模拟TDMM对iTreg诱导和Th 17减毒的体外作用以及对表型维持的体内作用;以及（3）：确定TDMM诱导的TTreg和TDMM减毒的Th 17细胞转移至淋巴细胞减少小鼠和实验诱导的结肠炎小鼠后的功能和稳定性。

 DESCRIPTION (provided by applicant): Regulatory T cells (Tregs) comprise a heterogeneous class of lymphocytes that are able to promote immune tolerance in peripheral tissue through cytokine secretion and modulation of dendritic cell function. Methods currently exist to selectively expand Tregs in vitro in presence of TGF-b (induced or iTregs) and transfer to patients for therapeutic inhibition of inflammation in those suffering from inflammatory bowel disease, graft- versus-host disease and other pathologies characterized by excessive inflammation. Although the adoptive transfer of iTregs has the promise to be safe in the clinic, major hurdles such as still exist in the translation of this therapeutic strategy. For example, the iTregs transferred into a patient with acute or chronic inflammation could transition from the anti inflammatory, iTreg phenotype to a pro-inflammatory, Th17 phenotype under the influence of inflammatory cytokines present in the microenvironment, and thereby, negatively contribute to the inflammatory state. Therefore, it is important to generate iTregs that possess a stable regulatory phenotype and function when introduced into an inflammatory microenvironment. Several studies link in vivo Treg development to the presence of an abundant and diverse microbial population in the intestinal tract (the microbiota). Although the microbiota's role in physiologic immune tolerance is poorly understood, a prevalent hypothesis is that the microbiota produces specific factors that promote Treg induction and modulate gut immunity towards a tolerant state. We previously demonstrated that indole, a microbiota metabolite derived from dietary tryptophan and present in the GI tract of both healthy mice and humans, attenuate indicators of inflammation. Unpublished data from our lab also show that, after conditioning in vitro in the presence of indole and iTreg-skewing conditions, CD4+ CD25- naïve T cells dramatically expand into Foxp3+ iTregs. However, iTreg stability and function can be synergistically increased or attenuated by several pro- and anti-inflammatory cytokines, and therefore, the ability to systematically predict the relationship of microbiota metabolite regulatin of Treg stability and function in inflammatory environments would contribute to our understanding of Treg immunobiology and advance Treg cell-based therapy. Our overall hypothesis is that tryptophan derived microbiota metabolites (TDMMs) induce a Treg phenotype with enhanced stability in vivo. Using Treg and Th17 data from exposure to different tryptophan derived microbiota metabolites, we propose to develop neural network models for Treg induction in vitro and stability post-transfer in vivo in the presence of indole, and use the model for generating testable predictions on optimal Treg induction, function and stability. The specific aims are: (1): To comprehensively determine the phenotype and function of TDMM-induced iTregs and Th17 cells in vitro; (2): Model the effect of TDMM on iTreg induction and Th17 attenuation in vitro and phenotype maintenance in vivo; and (3): To determine the function and stability of TDMM-induced Tregs and TDMM- attenuated Th17 cells after transfer to lymphopenic mice and mice with experimentally induced colitis.