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

摘要 IBD影响1.3%的美国成年人。尽管靶向TNFα和IL-23的抗体疗法取得了成功， 很大一部分患者没有达到缓解，需要寻找新的致病性 可以有针对性的途径。IBD的发病机制依赖于肠道的适当调节， 免疫力考虑到它们在肠粘膜中的组成性存在，第3组先天淋巴样细胞（ILC 3） 在维持肠道内环境稳定方面起着关键作用。ILC 3对于防御细胞外 细菌通过分泌IL-17和IL-22。然而，在先天免疫性结肠炎的小鼠模型中， ILC 3的不适当激活是病理学的主要驱动因素。因此，全面了解 ILC 3生物学特性对于潜在靶向其在IBD中的作用至关重要。由于它们靠近肠道 在管腔中，ILC 3进行许多代谢适应以适应周围环境， 环境为了系统地描述这些适应，我们进行了非靶向代谢组学研究。 主要肠ILC亚群的分析。结合对先前生成的RNA的分析， 根据肠ILC的测序数据，我们鉴定了多胺的显著富集， ILC 3多胺代谢酶。多胺是精氨酸代谢的产物， 在癌症、衰老和自身免疫中的作用。从机制上讲，它们参与了扩散， 染色质可及性以及翻译延伸和终止。初步数据显示， 膳食多胺正调节ILC 3的丰度。我们还发现多胺的抑制作用 使用药物DFMO的合成损害了ILC 3的IL-22产生。此外，行政 DFMO在体内已被证明会加剧肠道病原体C的感染。啮齿动物。 考虑到这些前提，我们假设多胺正调控ILC 3功能 并有助于ILC 3在结肠炎中的免疫调节作用。我们将质疑这些假设 目的1：评估细胞内多胺对ILC 3功能的影响， 稳态多胺的合成依赖于限速酶ODC 1。我们有 产生的RorcCreOdc 1flox/flox小鼠，其中多胺生物合成在所有基因中均被基因消除， 常规T细胞和ILC 3。通过研究这些小鼠（Odc 1 Δ ILC 3/T），我们将选择性地询问 多胺在ILC 3的丰度、功能能力和增殖中的重要性。目标2：评估 ILC 3-内在多胺代谢在感染性结肠炎模型中的作用。我们将评估 Odc 1缺陷型ILC 3在附着消退性细菌性结肠炎模型中的功能，C. 啮齿动物模型，其高度依赖于ILC 3衍生的IL-22的保护。这些研究将 进一步了解ILC 3的代谢适应以及靶向的潜在作用， 这些代谢途径来治疗炎症性肠病。

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.