Impact of polyamines on ILC3 function at steady state and in preclinical model of colitis

摘要 1.3%的美国成年人患有IBDS。尽管针对肿瘤坏死因子α和IL-23的抗体疗法取得了成功，但 很大一部分患者没有得到缓解，因此有必要寻找新的致病因素 可以作为目标的路径。IBD的发病机制依赖于肠道的适当调节 豁免权。鉴于它们在肠粘膜中的构成存在，第3组固有淋巴样细胞(ILC3) 在维持肠道内环境平衡方面起着关键作用。ILC3对于防御细胞外信号至关重要 细菌通过分泌IL-17和IL-22。然而，在先天性免疫性结肠炎的小鼠模型中， ILC3的不适当激活是病理的主要驱动因素。从而全面认识到 对ILC3生物学的研究对于潜在地针对它们在IBD中的作用是至关重要的。由于它们靠近肠道 Lumen，ILC3进行许多新陈代谢适应以适应周围环境 环境。为了系统地表征这些适应，我们进行了非靶向代谢组学。 主要肠道ILC亚群的特征。结合对先前产生的RNA的分析- 来自肠道ILC的测序数据，我们发现了显著的多胺和 ILC3中的多胺代谢酶。多胺是精氨酸代谢的产物，具有多种 在癌症、衰老和自身免疫中的作用。从机制上讲，它们参与了核扩散， 染色质的可及性，以及翻译延伸和终止。初步数据显示， 饮食中的多胺对ILC3的丰度有正向调节作用。我们还发现，抑制多胺 使用药物DFMO的合成会削弱ILC3产生IL-22的能力。此外，管理 体内的DFMO已被证明会加剧肠道病原体轮状芽胞杆菌的感染。 考虑到这些前提，我们假设多胺正向调节ILC3功能 并参与ILC3在结肠炎中的免疫调节作用。我们将审问这些假说 目标1：评估细胞内多胺对ILC3功能的影响 处于稳定状态。多胺的合成依赖于限速酶ODC1。我们有 产生了RorcCreOdc1FLOX/FLOX小鼠，在这些小鼠中，多胺的生物合成全部被基因消融 常规T细胞和ILC3。通过研究这些小鼠(Odc1ΔILC3/T)，我们将有选择地询问 多胺在ILC3的丰度、功能和增殖中的重要性。目标2：评估 ILC3内源性多胺代谢在感染性结肠炎模型中的作用。我们将评估 Odc1缺失的ILC3在附着消失性细菌性结肠炎模型中的作用。 轮牙模型，高度依赖ILC3来源的IL-22提供保护。这些研究将 进一步了解ILC3的代谢适应以及靶向的潜在作用 这些代谢途径治疗炎症性肠病。

ABSTRACT IBDs affect 1.3% of U.S. adults. Despite the success of antibody therapies targeting TNFα and IL-23, a significant fraction of patients does not achieve remission, necessitating the search for novel pathogenic pathways that can be targeted. The pathogenesis of IBD is dependent on proper regulation of intestinal immunity. Given their constitutive presence in the intestinal mucosa, group 3 innate lymphoid cells (ILC3) play a pivotal role in maintaining intestinal homeostasis. ILC3 are vital for defense against extracellular bacteria through the secretion of IL-17 and IL-22. However, in mouse models of innate immune colitis, inappropriate activation of ILC3 is a main driver of pathology. Thus, a comprehensive understanding of ILC3 biology is crucial for potentially targeting their role in IBD. Due to their proximity to the intestinal lumen, ILC3 make a number of metabolic adaptations to accommodate the surrounding environment. To systematically characterize these adaptations, we performed untargeted metabolomic profiling of the major intestinal ILC subsets. In combination with analysis of previously generated RNA- sequencing data from intestinal ILCs, we identified a significant enrichment of polyamines and polyamine metabolic enzymes in ILC3. Polyamines are products of arginine metabolism with diverse functions in cancer, aging, and autoimmunity. Mechanistically, they participate in proliferation, chromatin accessibility, as well as translation elongation and termination. Preliminary data shows that dietary polyamines positively regulate the abundance of ILC3. We also found that inhibition of polyamine synthesis using the drug DFMO impairs IL-22 production by ILC3. Furthermore, administration of DFMO in vivo has been shown to exacerbate infection by the intestinal pathogen C. rodentium. Considering these premises, we hypothesize that polyamines positively regulate ILC3 function and contribute to the immunoregulatory role of ILC3 in colitis. We will interrogate these hypotheses in the following aims: Aim 1: To evaluate the impact of intracellular polyamines on ILC3 function at steady state. Synthesis of polyamines is dependent on the rate-limiting enzyme ODC1. We have generated RorcCreOdc1flox/flox mice, in which polyamine biosynthesis is genetically ablated in all conventional T cells and ILC3. By studying these mice (Odc1ΔILC3/T), we will selectively interrogate the importance of polyamines in abundance, functional capacity and proliferation of ILC3. Aim 2: To assess the contribution of ILC3-intrinsic polyamine metabolism in a model of infectious colitis. We will assess the function of Odc1-deficient ILC3 during a model of attaching effacing bacterial colitis, the C. rodentium model, which is highly dependent on ILC3-derived IL-22 for protection. These studies will further our understanding of the metabolic adaptations of ILC3 as well as the potential role for targeting these metabolic pathways to treat inflammatory bowel diseases.