Endosomal Control of Microbe-Host Homeostasis

微生物宿主稳态的内体控制

• 批准号: 8874972
• 负责人: Nan Gao
• 金额: $ 34.44万
• 依托单位: RUTGERS THE STATE UNIV OF NJ NEWARK
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8874972
• 关键词: 15q22; Ablation; Agonist; Alleles; Biochemical; Biological Assay; CXCL1 gene; Cell Line; Cell Proliferation; Chromosomes; Coculture Techniques; Colon; Crohn' s disease; Data; Disease; Disease model; Disease susceptibility; Drosophila genus; Endosomes; Enteral; Enterocytes; Environment; Epithelial Cells; Equilibrium; Genes; Genetic Models; Genetic Predisposition to Disease; Germ-Free; Goals; Guanosine; Health; Homeostasis; Human; Human Chromosomes; Hyperplasia; Immune; Immune response; Immune system; Inflammatory; Inflammatory Bowel Diseases; Inflammatory Response; Inflammatory Response Pathway; Injury; Interleukin-6; Intestines; Knockout Mice; Laboratories; Learning; Link; Mediating; Medical; Microbe; Modeling; Molecular; Mucosal Immunity; Mus; Neoplasms; Organoids; Pathogenesis; Pathway interactions; Perfusion; Physiological; Predisposition; Premature Mortality; Production; RNA Interference; Recycling; Side; Signal Transduction; Sorting - Cell Movement; Stem cells; Testing; Tissues; Toll-like receptors; Ulcerative Colitis; cell type; cytokine; early onset; enteritis; gut microbiota; improved; in vivo; inflammatory modulation; innovation; intestinal epithelium; knockout animal; microbial; microorganism; mouse model; novel; paracrine; receptor; research study; response; sensor; stem; tissue regeneration; villin

DESCRIPTION (provided by applicant): The intestinal epithelium (IEC) with its luminal microflora serves as an ideal experimental and medical model that merges innate immune recognition in the context of a tissue regeneration environment. Genetic predispositions that cause imbalanced microbe-host interaction may contribute to the pathogenesis of inflammatory bowel disease (IBD). Various susceptibility loci for Crohn's disease and ulcerative colitis have been identified; however, their contributions to the disease mechanism remain poorly defined. A Crohn's disease susceptibility locus at chromosome 15q22 is immediately linked to RAB11A. This gene encodes a small guanosine triphosphatase (GTPase) that regulates the recycling endosome function. The applicant's laboratory has genetically targeted the mouse Rab11a, and analyzed IEC-specific Rab11a knockout mice. Preliminary data suggested that Rab11a controls epithelial-cell-intrinsic inflammatory cytokine response to enteric microbiota. Enterocytes deficient in Rab11a in Drosophila and mouse intestines overproduced proinflammatory cytokines, and caused early-onset enteritis, higher susceptibility to inflammatory neoplasia, and premature mortality. The long- term goal is to understand how the endosomal sorting of microbial receptors in IECs influences innate mucosal immunity and microbe-host homeostasis. The objective of this proposal is to establish the molecular mechanisms, by which Rab11a endosome-mediated sorting of Toll-like receptors (TLRs), in particular TLR9, support intestinal mucosal tolerance to microbiota. The central hypothesis is that Rab11a sequesters TLR9 to an inactive endosomeal compartment and dampens unwanted immune response to enteric microbiota at steady state conditions. Information learned about IEC-mediated modulation of inflammatory cytokine production and immune response may help reduce the adverse inflammatory response in IBD. This hypothesis will be tested with 2 specific aims: (1) to establish Rab11a endosomal compartment as an epithelial-cell-intrinsic modulator of cytokine response to microbiota; and (2) to determine the mechanism of Rab11a-controlled TLR9 transport and activation in response to microbial agonists. The experiments will use the novel Rab11a conditional mouse model that facilitates inducible Rab11a deletion, IEC-specific Drosophila Rab11 RNA interference (RNAi) lines, RAB11A-depleted human colon epithelial cell lines, and in vivo perfusion of microbial agonists. The combination of these genetic models with in vivo physiologic analyses in the study of endocytic control of microbe-host homeostasis is innovative and a major step toward understanding IBD.

描述（由申请人提供）：肠上皮（IEC）及其发光菌群是一种理想的实验和医学模型，在组织再生环境的背景下合并了先天免疫识别。引起微生物宿主相互作用不平衡的遗传易感性可能有助于炎症性肠病（IBD）的发病机理。已经发现了克罗恩病和溃疡性结肠炎的各种敏感位点；但是，它们对疾病机制的贡献仍然很差。 15q22染色体的克罗恩病敏感性基因座立即与Rab11a相关。该基因编码一个小的鸟嘌呤三磷酸酶（GTPase），该三磷酸酶（GTPase）调节回收内体功能。申请人的实验室已遗传针对小鼠RAB11A，并分析了IEC特异性RAB11A敲除小鼠。初步数据表明，RAB11A控制上皮细胞内炎性细胞因子对肠菌群的反应。果蝇和小鼠肠中Rab11a缺乏的肠细胞过量产生了促炎细胞因子，并引起早发性肠炎，较高的炎症性肿瘤易感性和过早死亡。长期的目标是了解IEC中微生物受体的内体分选如何影响先天粘膜免疫和微生物宿主体内平衡。该提案的目的是建立分子机制，rab11a内体介导的Toll样受体（TLR）的分类，特别是TLR9，支持对微生物群的肠粘膜耐受性。中心假设是Rab11a将TLR9隔离为无活性的内体室，并在稳态条件下抑制对肠性微生物群的不良免疫反应。有关IEC介导的炎症细胞因子产生和免疫反应调节的信息可能有助于减少IBD的不良炎症反应。该假设将以2个特定的目的进行检验：（1）将Rab11a内体室建立为细胞因子对微生物群的上皮细胞内膜调节剂； （2）确定Rab11a控制的TLR9转运和激活对微生物激动剂的机制。该实验将使用新型的RAB11A条件小鼠模型，该模型促进了可诱导的Rab11a缺失，IEC特异性果蝇Rab11 RNA干扰（RNAI）线，RAB11A耗尽的人类结肠上皮细胞系，以及微生物养老金的体内灌注。这些遗传模型与体内生理分析的组合在对微生物宿主体内稳态的内吞控制的研究中是创新的，也是理解IBD的重要一步。