Determinants of induced Treg and inflammatory Th17 cell balance in response to potentially pathogenic microbiota

诱导 Treg 和炎症 Th17 细胞平衡响应潜在致病微生物群的决定因素

• 批准号: 10579197
• 负责人: Dan Littman
• 金额: $ 52.11万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-15 至 2026-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10579197
• 关键词: Adopted; Affect; Antibodies; Antigen Presentation; Antigen-Presenting Cells; Autoimmune Diseases; Bacteria; Bone Marrow; CD4 Positive T Lymphocytes; Cell Communication; Cell Differentiation process; Cell Line; Cell physiology; Cells; Characteristics; Chimera organism; Chronic; Colon; Complement; Cre driver; Crohn' s disease; Dangerousness; Data; Data Set; Dendritic Cells; Docking; Endothelial Cells; Environmental Exposure; Environmental Risk Factor; Epithelial Cells; Equilibrium; Exposure to; FOXP3 gene; Genetic; Genetic Models; Genetic Predisposition to Disease; Goals; Health Benefit; Helicobacter hepaticus; Heterozygote; Histocompatibility Antigens Class II; Homeostasis; ITGAX gene; Immune system; Impairment; In Vitro; Infection; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Integrin alphaV; Interleukin-10; Intestines; Lamina Propria; Leukocytes; Location; Lymphoid Cell; MHC Class II Genes; Macrophage; Maintenance; Mediating; Microbe; Modeling; Mouse Strains; Mus; Mutant Strains Mice; Mutate; Mutation; Myeloid Cells; Pathogenicity; Pathway interactions; Phenotype; Physiological; Population; Process; Province; Regulation; Regulatory T-Lymphocyte; Reporter; Research; Risk; Role; Sorting; Specific qualifier value; Study models; System; T cell differentiation; T cell response; T-Cell Activation; T-Lymphocyte; Therapeutic; Transforming Growth Factor beta; Transgenic Organisms; Tumor Immunity; Ulcerative Colitis; Work; candidate identification; cell type; commensal bacteria; cytokine; dysbiosis; embryonic stem cell; experimental study; gut inflammation; gut microbiota; immunological synapse formation; intestinal barrier; intestinal homeostasis; intravital microscopy; lymph nodes; mesenteric lymph node; microbial; microbiota; microorganism; migration; multiphoton microscopy; new therapeutic target; pathobiont; pathogen; programs; receptor; response; single-cell RNA sequencing; spatiotemporal; transcription factor; transcriptomics; villin

Interactions of the gut microbiota with cells of the immune system govern multiple physiological functions that are manifested locally, in the regulation of intestinal barrier functions, and systemically, in autoimmune diseases and modulation of anti-tumor immunity. Although mutualistic microbial species generally provide vital health benefits to the host, some of them can conditionally cause harm under some circumstances, such as host genetic vulnerabilities or following environmental perturbation. These bacterial species, known as “pathobionts”, have been proposed to be major contributors to inflammatory bowel diseases (IBD) such as ulcerative colitis and Crohn’s disease, which are characterized by intestinal dysbiosis. A better characterization of these bacterial species and the mechanisms by which they interact with the host in healthy homeostatic conditions and during IBD-associated inflammation is critical for developing better therapeutic approaches. We study the model pathobiont Helicobacter hepaticus, which induces regulatory T cells (iTreg) in the healthy murine gut, but promotes Th17-mediated inflammation when the iTregs are compromised. H. hepaticus- specific naïve T cells are activated by antigen-presenting cells (APCs) in colon-draining mesenteric lymph nodes (mLN), and up-regulate Foxp3 and RORgt, transcription factors characteristic of intestinal iTreg. However, when IL-10 is limiting or when iTreg induction is otherwise compromised, the microbe-specific T cells express RORgt and adopt a pathogenic (p)Th17 cell program in the lamina propria. The goals of this proposal are to identify the APCs that interact with naïve H. hepaticus-specific T cells in the mLN to program either iTreg or pTh17 differentiation pathways, elucidate the molecules involved and the temporal dynamics of the APC-T cell interactions, and determine the roles of the diverse types of MHC class II-expressing cells in the intestinal lamina propria in promoting iTreg and pTh17 cell functions. In preliminary studies, we found that selective loss of either CCR7 in dendritic cells (DCs) or MHC-II in type 3 innate lymphoid cells (ILC3) resulted in abrogation of iTreg cell differentiation and in expansion, instead, of pTh17 cells in mLN and lamina propria. A similar iTreg phenotype was observed when molecules involved in TGF-b release were mutated in DCs or ILC3, suggesting that regulated local release of this iTreg-inducing cytokine requires naïve T cells to interact with both DCs and ILC3. Our first aim is to precisely characterize, through genetic and transcriptomic approaches, the cell types required for iTreg induction in the mLN, and rule out potential for misinterpretation due to expression of Cre in rare uncharacterized APCs or to indirect effects of the cell type-restricted mutations; and determine the spatiotemporal interactions of the cells, using multiphoton microscopy. The second aim is to identify the CCR7- independent APC(s) required for pTh17 cell induction in settings of compromised iTreg induction. The third aim is to leverage the H. hepaticus-specific system to investigate potential non-T cell priming functions of diverse MHC-II-expressing cell types in the intestinal lamina propria, including epithelial and endothelial cells.

肠道微生物群与免疫系统细胞的相互作用控制着多种生理功能 局部表现为肠道屏障功能的调节，全身表现为自身免疫 尽管共生微生物物种通常提供重要的作用。 对宿主的健康有益，其中一些在某些情况下可能有条件地造成伤害，例如 这些细菌物种被称为宿主遗传脆弱性或环境扰动。 “pathobionts”被认为是炎症性肠病（IBD）的主要促成因素，例如 溃疡性结肠炎和克罗恩病，其特征是肠道菌群失调。 这些细菌种类及其在健康体内平衡中与宿主相互作用的机制 条件和 IBD 相关炎症期间对于开发更好的治疗方法至关重要。 研究模型致病菌肝螺杆菌，它在健康人体内诱导调节性 T 细胞 (iTreg) 小鼠肠道，但当 iTreg 受损时会促进 Th17 介导的炎症。 结肠引流肠系膜淋巴中的抗原呈递细胞 (APC) 激活特定的初始 T 细胞 节点 (mLN)，并上调 Foxp3 和 RORgt，肠道 iTreg 的转录因子特征。 然而，当 IL-10 受到限制或 iTreg 诱导受到其他损害时，微生物特异性 T 细胞 表达 RORgt 并在固有层采用致病性 (p)Th17 细胞程序。 的目的是识别与 mLN 中的幼稚肝嗜血杆菌特异性 T 细胞相互作用的 APC，以对 iTreg 进行编程 或 pTh17 分化途径，阐明所涉及的分子和 APC-T 的时间动态 细胞相互作用，并确定肠道中不同类型的 MHC II 类表达细胞的作用 固有层在促进iTreg和pTh17细胞功能方面的作用在初步研究中，我们发现选择性丧失。 树突状细胞 (DC) 中的 CCR7 或 3 型先天淋巴细胞 (ILC3) 中的 MHC-II 导致废除 类似的 iTreg 细胞在 mLN 和固有层中分化和扩增。 当 DC 或 ILC3 中参与 TGF-b 释放的分子发生突变时，观察到表型，这表明 调节这种 iTreg 诱导细胞因子的局部释放需要幼稚 T 细胞与 DC 和 ILC3。我们的首要目标是通过遗传和转录组学方法精确表征细胞类型。 mLN 中 iTreg 诱导所需的，并排除由于 Cre 表达而导致误解的可能性 罕见的未表征的 APC 或细胞类型限制性突变的间接影响；并确定 使用多光子显微镜观察细胞的时空相互作用第二个目标是识别 CCR7-。 在 iTreg 诱导受损的情况下，pTh17 细胞诱导所需的独立 APC 第三个目标。 的目的是利用肝嗜血杆菌特异性系统来研究不同来源的潜在非T细胞启动功能 肠固有层中表达 MHC-II 的细胞类型，包括上皮细胞和内皮细胞。