Toll-like receptor 9 proteolytic processing and signaling

Toll 样受体 9 蛋白水解加工和信号转导

• 批准号: 8463979
• 负责人: CYNTHIA A LEIFER
• 金额: $ 7.74万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-05-01 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8463979
• 关键词: Address; Allergic Disease; Asthma; Autoantibodies; Autoimmune Diseases; Autoimmune Process; Autoimmunity; B-Lymphocytes; Biochemistry; Biological Models; C-terminal; Cells; Chemistry; Chimeric Proteins; Clinical; Critical Pathways; DNA; DNA Binding; DNA Structure; Data; Dendritic Cells; Development; Discrimination; Disease; Drug Targeting; Endocytosis; Endosomes; Engineering; Event; Family; Host Defense; Immune; Immune response; Immunologic Receptors; Infection; Inflammation; Inflammatory; Interferons; Lead; Left; Ligands; Malignant Neoplasms; Measures; Mediating; Methylation; Microbe; Modeling; Molecular; Mutation; N-terminal; NF-kappa B; Natural Immunity; Nucleic Acids; Pathology; Pathway interactions; Peptide Hydrolases; Play; Positioning Attribute; Prevalence; Production; Proteolysis; Proteolytic Processing; Publishing; RNA; Reaction; Receptors, Antigen, B-Cell; Regulation; Regulatory Pathway; Role; Signal Transduction; Site; Site-Directed Mutagenesis; Specificity; Structure; Systemic Lupus Erythematosus; T-Lymphocyte; TEV protease; TLR4 gene; TLR9 gene; Testing; Therapeutic; Tissues; Toll-like receptors; Transfection; Translating; Vaccine Adjuvant; Vertebral column; Wound Healing; cell type; drug development; extracellular; innovation; macrophage; member; microbial; mouse model; mutant; new therapeutic target; novel; prevent; receptor; reconstitution; response; retroviral transduction; standard of care; tool; trafficking

DESCRIPTION (provided by applicant): Therapeutically targeting inflammation induced by innate immunity has the potential to reduce disease associated pathology; however, the first step in translating potential to clinical reality is defining the molecular pathways critical for regulating innate immunity, and identifying targets within these pathways that can be modulated. Significant progress has been made in delineating the molecular pathways regulating one member of the nucleic acids-sensing family of Toll-like receptors (TLRs), which have been implicated in development of autoimmune disease. Recent studies suggest that one of these TLRs, TLR9, is a pro-receptor that is activated by proteases in acidic endosomes. This cleavage removes an N-terminal fragment, leaving a C-terminal fragment, called p80, which is proposed to be the functional form of TLR9. This pathway has been touted as a new and potentially important drug target to reduce autoimmune inflammation. However, our preliminary results demonstrate that proteolytic cleavage of TLR9 does not occur in B cells, which respond robustly to TLR9 ligands. Moreover, we show that the p80 form of TLR9 is insufficient to support signaling in highly relevant macrophages, and dendritic cells. We review data that shows the N-terminal fragment, which is removed during the proteolytic event, has DNA binding activity. Therefore, we propose the hypothesis that the N-terminal fragment plays a critical role in determining the ligand specificity and response of the receptor. We will test this hypothesis in two aims, which define the role of the N-terminus in regulating specificity of the receptor, and the role of the cleavage event in regulating signaling and trafficking in various cell types including B cells, macrophages and dendritic cells. While we use TLR9 as a model system, recent published studies showed that other nucleic acid sensing TLRs are regulated by similar mechanisms. This study will provide critical new information that will help clarify controversies i the field. But more importantly, will determine whether proteolysis is, in fact, a promising new pathway for drug development, or of lesser significance compared with other regulatory mechanisms.

描述（由申请人提供）：治疗靶向由先天免疫引起的炎症有可能减少疾病相关的病理；但是，将潜力转化为临床现实的第一步是定义分子途径对于调节先天免疫至关重要，并确定可以调节的这些途径中的靶标。在描述调节核酸感应受体（TLR）的一个成员的分子途径方面取得了重大进展，这与自身免疫性疾病的发展有关。最近的研究表明，其中一种TLR是TLR9，是一种受酸性内体蛋白酶激活的促肌感受器。这种切割消除了N末端片段，留下了称为p80的C末端片段，该片段被认为是TLR9的功能形式。该途径已被吹捧为减少自身免疫性炎症的一种新的且潜在的药物靶标。然而，我们的初步结果表明，在B细胞中不会发生TLR9的蛋白水解裂解，这对TLR9配体反应良好。此外，我们表明TLR9的p80形式不足以支持高度相关的巨噬细胞和树突状细胞中的信号传导。我们回顾了显示的数据显示，在蛋白水解事件中去除的N末端片段具有DNA结合活性。因此，我们提出了以下假设：N末端片段在确定受体的配体特异性和反应中起着关键作用。我们将在两个目标中检验这一假设，该假设定义了N末端在调节受体特异性中的作用，以及裂解事件在调节包括B细胞，巨噬细胞和树突状细胞在内的各种细胞类型中的信号传导和运输中的作用。虽然我们使用TLR9作为模型系统，但最近发表的研究表明，其他核酸传感TLR受到相似机制的调节。这项研究将提供关键的新信息，这将有助于阐明该领域的争议。但更重要的是，将确定蛋白水解实际上是有希望的药物开发途径，还是与其他调节机制相比的意义较小。