The human B cell toll-like receptor 4 complex

人类 B 细胞 Toll 样受体 4 复合物

• 批准号: 8382951
• 负责人: LISA M GANLEY-LEAL
• 金额: $ 23.85万
• 依托单位: RHODE ISLAND HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-07 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8382951
• 关键词: Ablation; Affect; Antibodies; B-Lymphocytes; Bacteria; CD14 Antigen; Characteristics; Chronic; Chronic Disease; Clinical; Clonality; Cloning; Complex; Critical Pathways; Data; Development; Disease; Epithelial; Equilibrium; Escherichia coli; Etiology; Exhibits; Exploratory/Developmental Grant; Gastrointestinal Diseases; Genes; Genetic Polymorphism; Goals; Homeostasis; Human; Immune system; Immunoglobulin A; Immunology; Inflammatory; Inflammatory Bowel Diseases; Inflammatory Response; Intestines; Knowledge; Leukocytes; Ligands; Lipid A; Lipopolysaccharides; Literature; Mediating; Microbe; Modification; Mucous Membrane; Myelogenous; Myeloid Cells; Pathogenesis; Pathway interactions; Patients; Pattern recognition receptor; Phosphotransferases; Play; Production; Reporting; Role; Structure; TLR4 gene; Testing; Transfection; Vaccines; Variant; Work; base; clinically relevant; clinically significant; commensal microbes; genome wide association study; high risk; improved; microbial; microbial host; microorganism antigen; microorganism interaction; novel; pathogenic bacteria; receptor; response; toll-like receptor 4

DESCRIPTION (provided by applicant): The host-microbial interactions at the mucosa require a delicate, although poorly understood, balance where the presence of commensal and pathogenic bacteria requires discriminatory responses. Although the normal microbes of the gut are not pathogenic if they remain within their gut micro-niche, they will induce an inflammatory response if they cross the epithelial barrier. The persistence of translocated bacteria is thought to play an important role in the etiology and pathogenesis of inflammatory bowel disease (IBD). Inconsistencies in the literature regarding the role of bacteria-sensing genes in IBD suggest a higher level of complexity to this host-microbe interaction than has been appreciated. Some of our gaps in knowledge may be explained by the poorly defined role of one of the most abundant leukocytes in the mucosa, the B cell. B cells express Toll-like receptor (TLR) 4, the receptor for lipopolysaccharide (LPS), in IBD and likely have an important role in sensing microbes. Paradoxically, despite TLR4 expression, patient B cells generally respond poorly to E. coli LPS. In contrast, TLR4+ B cells respond to LPS molecules with characteristics of hypo-acylated lipid A, a group of ligands shown to be antagonistic for myeloid TLR4. The objective of this application is to define the potentially novel and dynamic TLR4 complex expressed by human B cells and the functional significance of B cell TLR4 responses in IBD. Our central hypothesis is that B cell TLR4 is a dynamic complex that allows recognition of hypo-acylated LPS through TRIL, a novel TLR4 co-receptor, and structural modification TLR4. Our hypothesis is based on our exciting data on disease-specific changes in the B cell TLR4 complex and our recent report demonstrating that B cells from IBD patients respond to hypo-acylated LPS by secreting IgA. We thus further hypothesize that TLR4 stimulates a restricted IgA repertoire, which exhibits broad reactivity and helps to protect the mucosa. We will test our hypothesis through two Specific Aims. In the first aim, we will define the human B cell TLR4 complex by identifying the required co-receptors through ablation and addition studies using primary B cells from patients. We will also define the effect of potential structural modification(s) of TLR4 that may affect recognition of LPS through targeted sequencing and cloning of identified B cell TLR4 variants. Data will be correlated with clinical parameters of IBD and polymorphisms in TLR4. In the second aim, we will define the mechanism(s) of TLR4-mediated IgA production by evaluating gene and kinase activation and the clonality of the B cell response through targeted sequencing of the V region of IgA. The data generated in this proposal will have direct clinical relevance by identifying critical pathways for the development of improved treatments that change the course of disease. Further, by defining how B cells recognize LPS, we will also advance the field of genome-wide association studies, human B cell immunology, and mechanism(s) of the human-microbial interface implicated in many chronic diseases. PUBLIC HEALTH RELEVANCE: Inflammatory bowel disease (IBD) is a chronic gastrointestinal disease for which we have no cure. In this proposal, we hope to identify new ways in which our immune system interacts with the friendly bacteria of the intestines in hopes of developing treatments for patients with IBD.

描述（由申请方提供）：粘膜处的宿主-微生物相互作用需要一种微妙的平衡，尽管对这种平衡了解甚少，但存在的寄生菌和致病菌需要区别性反应。虽然肠道的正常微生物如果保持在它们的肠道微生态位内就不是致病性的，但是如果它们穿过上皮屏障，它们将诱导炎症反应。易位细菌的持续存在被认为在炎症性肠病（IBD）的病因和发病机制中起重要作用。关于细菌敏感基因在IBD中的作用的文献中的研究表明，这种宿主-微生物相互作用的复杂性比人们所认识的要高。我们在知识上的一些差距可能是由于粘膜中最丰富的白细胞之一B细胞的作用定义不清。B细胞在IBD中表达Toll样受体（TLR）4（脂多糖（LPS）的受体），并且可能在传感微生物中具有重要作用。奇怪的是，尽管TLR 4表达，患者B细胞通常对E. coli LPS。相反，TLR 4 + B细胞对具有低酰化脂质A特征的LPS分子产生应答，低酰化脂质A是一组显示出对髓样TLR 4具有拮抗作用的配体。本申请的目的是确定由人B细胞表达的潜在的新颖的和动态的TLR 4复合物以及B细胞TLR 4应答在IBD中的功能意义。我们的中心假设是，B细胞TLR 4是一种动态复合物，其允许通过TRIL（一种新型TLR 4共受体）和结构修饰TLR 4识别低酰化LPS。我们的假设是基于我们关于B细胞TLR 4复合物中疾病特异性变化的令人兴奋的数据和我们最近的报告，该报告表明来自IBD患者的B细胞通过分泌伊加对低酰化LPS作出反应。因此，我们进一步假设，TLR 4刺激一个有限的伊加库，表现出广泛的反应性，并有助于保护粘膜。我们将通过两个具体目标来检验我们的假设。在第一个目标中，我们将通过使用来自患者的原代B细胞的消融和添加研究鉴定所需的共受体来定义人B细胞TLR 4复合物。我们还将通过靶向测序和克隆鉴定的B细胞TLR 4变体来确定可能影响LPS识别的TLR 4潜在结构修饰的作用。数据将与IBD的临床参数和TLR 4的多态性相关。在第二个目标中，我们将通过评估基因和激酶激活以及通过伊加的V区的靶向测序的B细胞应答的克隆性来定义TLR 4介导的伊加产生的机制。本提案中生成的数据将通过确定用于开发改变疾病进程的改进治疗的关键途径而具有直接的临床相关性。此外，通过定义B细胞如何识别LPS，我们还将推进全基因组关联研究、人类B细胞免疫学以及与许多慢性疾病有关的人类-微生物界面机制的领域。 公共卫生相关性：炎症性肠病（IBD）是一种慢性胃肠道疾病，我们无法治愈。在这项提案中，我们希望确定我们的免疫系统与肠道友好细菌相互作用的新方法，希望为IBD患者开发治疗方法。