Bacterial translocation to mesenteric adipose tissue drives pathogenic stromal-B cell interactions leading to inflammatory IgG

细菌易位至肠系膜脂肪组织驱动致病性基质 B 细胞相互作用，导致炎症 IgG

• 批准号: 10593509
• 负责人: Emilie Kristina Grasset
• 金额: $ 25.43万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-03 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10593509
• 关键词: Adipocytes; Adipose tissue; Affect; Antibodies; Antigen Receptors; Antigens; Automobile Driving; B-Cell Activation; B-Lymphocytes; Bacteria; Bacterial Antigens; Bacterial Translocation; Biopsy; Cell Communication; Cell physiology; Cells; Chronic; Collection; Crohn' s disease; Data; Development; Diagnosis; Disease; Etiology; Excision; Fatty acid glycerol esters; Flow Cytometry; Genes; Genetic Transcription; Germ-Free; Gnotobiotic; Gut Mucosa; Human; IgA Deficiency; Immune system; Immunoglobulin Class Switching; Immunoglobulin G; Immunoglobulin M; Immunology; Impairment; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Intestines; Lead; Left; Leptin; Ligation; Lymphoid; Mesentery; Microbe; Modeling; Mucous Membrane; Mus; Operative Surgical Procedures; Pathogenicity; Pathologic; Pathology; Patients; Phenotype; Plasma Cells; Production; Proliferating; Property; Proteins; Serum; Signal Transduction; Stromal Cells; Tissue Expansion; Tissues; Toll-like receptors; adipokines; antimicrobial; comparison control; cytokine; disease diagnosis; genetic signature; gut inflammation; in vivo; microbiota; murine colitis; new therapeutic target; reconstitution; recruit; response; therapeutic target; transcriptome sequencing

Project Summary Anti-microbial antibodies are predictive of Crohn’s disease (CD) diagnosis and are present in patients’ serum up to 5 years before diagnosis, and their accumulation is associated with complications, often requiring bowel resection surgery. In patients with CD, more bacteria translocate to the mesenteric adipose tissue (MAT) compared to controls and a subset of bacteria are exclusive to CD MAT. This coincides with the expansion of the MAT and its wrapping around the intestine, or “creeping fat”, a hallmark of inflamed CD-affected tissue, which also correlates with complications. The etiology of anti-microbial antibodies and creeping fat are unknown. Although B cells and stromal cells co-localize within fat-associated lymphoid clusters in creeping fat, and B and plasma cell signatures are among the most highly upregulated genes in creeping fat compared to healthy MAT, B cell function in this tissue is unknown. We hypothesize that the translocation of microbes to MAT prompts stromal cells in fat-associated lymphoid clusters to recruit B cells, which differentiate into protective IgM-secreting plasma cells, inhibiting systemic dissemination of bacterial antigens. Sustained CD-specific bacterial translocation to the MAT leads to chronic inflammation activating stromal cells to secrete cytokines driving IgG class-switch and differentiation to inflammatory anti-microbial IgG-secreting plasma cells. Adipocyte-derived leptin is elevated in MAT of CD patients and drives inflammation in mouse colitis models. As leptin activates B cells, we posit leptin further drives preferential class-switch to IgG. We will address this hypothesis in germfree mice reconstituted with cultured collections of bacteria isolated from CD or healthy donors, as well as in human MAT associated or not with inflamed intestine from patients with CD undergoing bowel resection surgery at Mount Sinai. In these models, we will evaluate which bacteria translocate to the MAT, how they activate stromal cells by deep characterization at the transcriptional and protein level and how they drive leptin production by adipocytes in biopsy cultures (Aim 1). Next, we will investigate direct and indirect effects of CD microbiota on MAT B cells and their shift from protective IgM to inflammatory IgG. To do so we will characterize CD microbiota- driven changes in B cell activation, proliferation, class-switching and differentiation to plasma cells. We will also determine the IgG-inducing properties of MAT and stromal cells exposed in vivo to CD or healthy donor microbiota. Finally, we will investigate how CD microbiota perturbs stromal-B cell cross-talk within fat-associated lymphoid clusters (Aim 2). By showing that MAT is able to mount microbiota-specific B cell responses, this proposal will expand the study of mucosal immunology to mucosa-associated adipose tissues. Since creeping fat and anti-microbial IgG correlate with complications in CD, these studies have the potential to uncover mechanisms underlying CD pathology and identify needed therapeutic targets.

项目摘要 抗微生物抗体可预测克罗恩氏病（CD）诊断，并且存在于患者的血清中 到诊断前的5年​​，它们的积累与并发症有关，通常需要肠 切除手术。在患有CD的患者中，更多的细菌转移到肠系膜脂肪组织（MAT） 与对照组和细菌的一部分相比，CD MAT独有。这与扩展相吻合 垫子及其围绕肠子或“蠕动脂肪”，这是受发炎的CD影响组织的标志 也与并发症相关。抗微生物抗体和蠕动脂肪的病因尚不清楚。 尽管B细胞和基质细胞在蠕动脂肪中与脂肪相关的淋巴样簇中共定位 与健康的垫子相比 该组织中的B细胞功能尚不清楚。我们假设微生物转移到垫子提示 脂肪相关的淋巴样簇中的基质细胞募集B细胞，该细胞分化为保护性IgM分泌 浆细胞，抑制细菌抗原的全身传播。持续的CD特异性细菌 易位到垫子会导致慢性炎症激活基质细胞，分泌驱动IgG的细胞因子 类别开关和与炎症性抗微生物IgG分泌浆细胞的分化。脂肪细胞衍生 CD患者MAT中瘦素升高，并在小鼠结肠炎模型中驱动注射。随着瘦素激活B 细胞，我们阳性瘦素进一步将优先类开关驱动到IgG。我们将在无效的情况下解决这一假设 与从CD或健康供体分离的细菌的培养的细菌以及人类的小鼠重组 与CD患者进行肠切除手术的患者发炎或与发炎的肠相关的垫子 西奈山。在这些模型中，我们将评估哪种细菌转移到垫子上，它们如何激活基质 通过在转录和蛋白质水平上进行深层表征，以及它们如何驱动瘦素的产生 活检培养物中的脂肪细胞（AIM 1）。接下来，我们将研究CD微生物群的直接和间接影响 MAT B细胞及其从受保护的IgM转移到炎性IgG。为此，我们将表征CD Microbiota- B细胞激活，增殖，类转换和与浆细胞分化的驱动变化。我们也会 确定在体内暴露于CD或健康供体的MAT和基质细胞的IgG诱导特性 微生物群。最后，我们将研究CD微生物群如何在脂肪相关的中 淋巴簇（AIM 2）。通过显示MAT能够安装微生物群特异性B细胞响应，这 提案将将粘膜免疫学的研究扩展到粘膜相关的脂肪组织。自从爬行以来 脂肪和抗微生物IgG与CD中的并发症相关，这些研究可能会发现 CD病理学的基础机制并确定所需的治疗靶标。