Dissecting the intestinal niche for regulatory T cells

剖析调节性 T 细胞的肠道生态位

• 批准号: 10480404
• 负责人: TERRI M. LAUFER
• 金额: --
• 依托单位: PHILADELPHIA VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-12-01 至 2026-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10480404
• 关键词: 3-Dimensional; Affect; Anatomy; Antibiotics; Autoimmune; B-Lymphocytes; Birth; Blocking Antibodies; CD4 Positive T Lymphocytes; Cell Communication; Cell Count; Cell physiology; Cells; Chemicals; Clinical; Colonoscopy; Crohn' s disease; Cytoprotection; Data; Defect; Development; Disease; Disease Outcome; Environment; Expression Profiling; FOXP3 gene; Flare; Flow Cytometry; Funding; Genomic Segment; Health; Homeostasis; Human; Image; Imaging Techniques; Immune; Immune system; Immunofluorescence Immunologic; Immunologics; Immunotherapy; Individual; Infant; Infection; Inflammation; Inflammatory Bowel Diseases; Intestines; Lamina Propria; Lead; Location; Lymphoid Follicle; Maintenance; Mature B-Lymphocyte; Mediating; Methodology; Methods; Modeling; Molecular; Mucosal Immune Responses; Mucous Membrane; Mus; Organ Donor; Organism; Pathway interactions; Patients; Peripheral; Phenotype; Physiological; Population; Positioning Attribute; Predisposition; Prevalence; Process; Recovery; Regulatory Pathway; Regulatory T-Lymphocyte; Research Design; Signal Transduction; Small Intestines; Specimen; Subcellular Anatomy; Therapeutic; Thymus Gland; Tissues; Ulcerative Colitis; Veterans; Villus; Wild Type Mouse; autoinflammatory; enteritis; experimental study; genetic manipulation; gut inflammation; gut microbiota; human tissue; improved; innovation; intestinal epithelium; intestinal homeostasis; lymphoid structures; lymphotoxin beta; men; microorganism; mouse model; mucosal site; organizational structure; pharmacologic; prevent; response; segregation; transcription factor

1. Objective: Inflammatory bowel diseases (IBD), including Crohns Disease and Ulcerative Colitis, arise in genetically-susceptible hosts when intestinal epithelial defects and heightened responsiveness towards commensal organisms lead to excessive activation of CD4+ T cells and tissue damage. IBD is also associated with loss of regulatory pathways including defects in regulatory T cells (Tregs). Tregs, a subset of Foxp3- positive CD4+ T cells, are central to intestinal tolerance; they prevent the development of IBD disease and suppress inflammation during infection. In this application, we seek to understand the mechanisms that maintain intestinal Tregs during health and inflammation. Regulatory T cells include two developmentally distinct subsets: thymus-derived (tTreg or natural (nTreg) and peripherally-derived (pTreg) that differentiate from conventional naïve CD4+ T cells. Human and mouse intestine contain cells of both lineages and both are necessary to maintain tolerance. Foxp3-deficient IPEX patients, lacking natural Tregs, develop autoimmune enteritis as infants. Separately, loss of the genomic region that controls peripheral differentiation of pTregs also leads to intestinal inflammation. Thus, both murine and human studies demonstrate a requirement for both populations for the maintenance of intestinal tolerance. There are no data defining distinct mechanistic or anatomic requirements for the two populations. Treg localization and phenotypes were examined in mice lacking peripheral TCR-MHCII interactions and peripheral conversion of Tregs (pTregs). Thymically-generated nTregs entered the small intestine lamina propria (siLP) to fill the compartment in the absence of MHCII. Imaging of intact tissue shows that Tregs in the siLP have two distinct anatomic locations: individually localized within the siLP villus or clustered within organized structures resembling isolated lymphoid follicles (ILFs). Our data suggest that a subset of Tregs preferentially localize to ILFs; this association is altered during infection. Additionally, nTregs and pTregs occupy an overlapping niche despite having different requirements for costimulatory signals. Thus, we present the hypotheses that 1. thymic-derived and peripheral Tregs occupy distinct physiologic niches in the small intestine, and 2 ILFs provide a niche for Tregs that is malleable during inflammation. 2. Research Design: In our first Aim, we will utilize murine models and healthy human tissue to determine if ILFs are required for the maintenance of siLP Tregs, define the costimulatory signals present in the ILF, and then ask if the ILF specifically attracts and maintains thymic Tregs in contrast to pTregs. Multiple studies in mice and men find that both infectious and autoimmune intestinal inflammation is associated with expansion of ILFs and altered Treg dynamics. Yet, there are no data on how these changes affect the positioning and maintenance of Tregs and recovery from inflammation. In our second Aim, we will examine murine models of inflammation and specimens from IBD patients to define how inflammation alters ILF-Treg interactions. 3. Methodology: Mice with altered MHCII expression will be compared with wildtype mice. Small intestine from healthy Our data suggest thymic Tregs preferentially localize to ILFs.and IBD patients will also be examined. The immune system will be altered utilizing blocking antibodies, antibiotics, genetic manipulations, and infections. Methods will include molecular and cellular analyses of cell populations and responses by flow cytometry, expression profiling, and imaging techniques. 4. Findings: This proposal not been funded. 5. Clinical Relationships: The prevalence of inflammatory bowel disease has been increasing amongst veterans. The current study is directed towards defining pathways that can be manipulated therapeutically to increase the number of localized regulatory T cells to improve IBD outcomes.

1. 目的：炎症性肠病（IBD），包括克罗恩病和溃疡性结肠炎，发生于 当肠上皮缺陷和仪器反应性时，遗传易感宿主 共生生物导致 CD4+ T 细胞过度激活，IBD 也与此相关。 调节途径缺失，包括调节性 T 细胞 (Treg)（Foxp3- 的一个子集）缺陷。 阳性 CD4+ T 细胞对于肠道耐受至关重要；它们可以预防 IBD 疾病的发展 在此应用中，我们试图了解感染过程中炎症的抑制机制。 在健康和炎症期间维持肠道调节性 T 细胞包括两种发育的调节性 T 细胞。 不同的子集：胸腺来源的（tTreg 或天然的（nTreg）和外周来源的（pTreg）区分 来自传统的幼稚 CD4+ T 细胞 人类和小鼠肠道含有这两种谱系的细胞，并且都是 Foxp3 缺陷的 IPEX 患者缺乏天然 Tregs，会产生自身免疫性疾病。 另外，控制 pTreg 外周分化的基因组区域也缺失。 因此，小鼠和人类研究都表明两者都需要。 没有数据定义不同的机制或机制。 两个人群的解剖学要求。 在缺乏外周 TCR-MHCII 相互作用的小鼠中检查 Treg 定位和表型 胸腺产生的 nTregs 进入小肠层。 在没有 MHCII 的情况下，固有组织 (siLP) 填充隔室 对完整组织的成像显示 Tregs 在 siLP 有两个不同的解剖位置：单独位于 siLP 绒毛内或聚集在 我们的数据表明，Tregs 的一个子集类似于孤立的淋巴滤泡 (ILF)。 优先定位于 ILF；此外，nTreg 和 pTreg 的这种关联也会发生改变。 尽管对共刺激信号有不同的要求，但它们占据了重叠的利基市场，因此，我们提出了这一点。 假设 1. 胸腺源性和外周性 Tregs 占据不同的生理生态位 小肠和 2 个 ILF 为 Tregs 提供了一个在炎症期间具有可塑性的生态位。 2. 研究设计：在我们的第一个目标中，我们将利用小鼠模型和健康的人体组织来确定是否 ILF 是维持 siLP Tregs 所必需的，定义了 ILF 中存在的共刺激信号，并且 然后询问与 pTreg 相比，ILF 是否专门吸引和维持胸腺 Tregs。 小鼠和人类发现，感染性和自身免疫性肠道炎症都与 ILF 和改变的 Treg 动态然而，没有数据表明这些变化如何影响定位和调节。 Tregs 的维持和炎症恢复在我们的第二个目标中，我们将检查小鼠模型。 炎症和 IBD 患者标本，以确定炎症如何改变 ILF-Treg 相互作用。 3.方法：将具有改变的MHCII表达的小鼠与野生型小肠小鼠进行比较。 我们的数据表明，胸腺 Tregs 优先定位于 ILF。并且 IBD 患者也会 免疫系统将通过阻断抗体、抗生素、基因操作进行改变。 方法将包括细胞群的分子和细胞分析以及流式反应。 细胞计数、表达谱和成像技术。 4. 结果：该提案尚未获得资助。 5. 临床关系：炎症性肠病的患病率一直在增加 目前的研究旨在确定可通过治疗手段来控制的途径。 增加局部调节性 T 细胞的数量以改善 IBD 结局。