Regulation of TLR signaling, Inflammation and Antigen Presentation by VPS33B

VPS33B 对 TLR 信号传导、炎症和抗原呈递的调节

基本信息

批准号：
10439913
负责人：
Helmut J Kramer
金额：
$ 67.9万
依托单位：
CINCINNATI CHILDRENS HOSP MED CTR
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-07-01 至 2026-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10439913
关键词：
Affect Antigen Presentation Antigen Presentation Pathway Apoptotic Arthrogryposis Bacteremia Bacteria Bacterial Infections Binding C Type Lectin Receptors CD8-Positive T-Lymphocytes Cell membrane Cell surface Cells Cessation of life Cholestasis Complex Data Dendritic Cells Development Disease Drosophila genus Early Endosome Endocytosis Endosomes Event Exposure to Failure Family Genes Goals Human Immune response Immune signaling Immunity Inflammation Inflammatory Inflammatory Response Innate Immune Response Innate Immune System Investigation Ligands Link MHC Class II Genes Membrane Fusion Microbe Molecular Mus Mutate Mutation Natural Immunity Necrosis Outcome Pathway interactions Patients Pattern recognition receptor Phagocytes Phagocytosis Phagosomes Phosphotransferases Play Proteins Publishing Receptor Activation Receptor Signaling Recurrence Regulation Role Sampling Sepsis Signal Transduction Signal Transduction Pathway Specificity Symptoms Syndrome T cell response TLR4 gene Testing Toll-like receptors Translating Vertebrates adaptive immunity antimicrobial base cell type cytokine fly human disease in vivo insight kidney dysfunction macrophage microbial mutant novel therapeutics paralogous gene protein function receptor recruit response trafficking unpublished works

项目摘要

Project Summary Initiation of innate immune responses depends on cognate interaction between germline-encoded pattern recognition receptors and their ligands (expressed by microbes). Following recognition, the receptors initiate activation of downstream signal transduction pathways that often involve recruitment of downstream adapters and kinases. The Toll-like receptor family of PRRs, which are the subject of current investigation, are expressed both on the plasma membrane and in the endosomes. Several recent studies have demonstrated that endocytosis of the plasma membrane TLRs (especially TLR4) plays a critical role in regulating both quality and magnitude of inflammatory responses in a responding macrophage. Other studies have demonstrated that TLR signaling enhances phagocytosis of microbial cargo but not of apoptotic cell cargo suggesting a degree of specificity that is not understood. In addition, although endocytosis of TLR4 and the events following endocytosis of TLR4 that influence signal transduction are very well studied, it is not entirely clear if and how endocytosis influences signaling downstream of other plasma membrane and endosomal TLRs. In our studies, we find that a protein called Vps33B regulates handling of the phagocytic and endocytic cargo following pattern recognition receptor activation. More importantly, Vps33B directly influences the outcome of signaling downstream of TLRs in mice and Toll- and IMD pathways in Drosophila. Mutations in the genes VPS33B and VPS16B are linked to a rare human disease called ARC (Arthrogryposis-renal dysfunction-cholestasis) syndrome. Both of these ARC genes encode paralogs of HOPS complex subunits suggesting a role in membrane fusions but how perturbation of function of these proteins results in a diverse spectrum of disease symptoms in ARC patients is not entirely clear. It has however been documented that ARC patients suffer from sepsis and recurrent bacterial infections and we were therefore investigated the role of these proteins in influencing immune responses. We find that in the absence of VPS33B, Drosophila respond vigorously to microbial insult. Exaggerated immune responses are generated in response to live or dead bacteria and purified ligands of the Toll and IMD pathway results in death of Vps33B mutant, but not wild-type flies. This function of Vps33B is conserved in vertebrates and we find that mouse macrophages lacking Vps33B secrete very high quantities of inflammatory cytokines, when stimulated by either plasma membrane or endosomal TLR ligands. We therefore hypothesize that activation of pattern recognition receptors and specifically TLRs leads to formation of specialized endosomes that depend on Vps33B for lysosomal fusion. Lack of Vps33B is likely to affect several aspects of innate and adaptive immunity and to test this hypothesis, we propose to 1. Define the molecular events that regulate Vps33B function in endosomal maturation, 2. Define the role of Vps33B-regulated TLR trafficking and signaling 3. Investigate the role of Vps33B in regulating cargo handling by DCs and 4. Investigate the role of Vps33B in regulating antigen presentation and adaptive immunity.

项目概要先天免疫反应的启动取决于种系编码模式之间的同源相互作用识别受体及其配体（由微生物表达）。识别后，受体启动下游信号转导途径的激活通常涉及下游接头的招募和激酶。 PRR 的 Toll 样受体家族是当前研究的主题，其表达位于质膜上和内体中。最近的几项研究表明质膜 TLR（尤其是 TLR4）的内吞作用在调节质量和响应巨噬细胞中炎症反应的强度。其他研究表明 TLR 信号传导增强了微生物货物的吞噬作用，但不增强凋亡细胞货物的吞噬作用，这表明一定程度的不被理解的特殊性。此外，尽管 TLR4 的内吞作用和内吞作用后的事件 TLR4 影响信号转导的机制已得到很好的研究，但尚不完全清楚是否以及如何内吞影响其他质膜和内体 TLR 下游的信号传导。在我们的研究中，我们发现一种名为 Vps33B 的蛋白质在模式识别后调节吞噬和内吞货物的处理受体激活。更重要的是，Vps33B直接影响TLR下游信号传导的结果小鼠中的Toll-和IMD途径以及果蝇中的Toll-和IMD途径。基因 VPS33B 和 VPS16B 的突变与一种罕见的人类疾病，称为 ARC（关节弯曲-肾功能障碍-胆汁淤积）综合征。这两个ARC 基因编码 HOPS 复合体亚基的旁系同源物，表明在膜融合中发挥作用，但扰动如何这些蛋白质的功能导致 ARC 患者出现多种疾病症状，但并不完全如此。清除。然而，有记录表明 ARC 患者患有败血症和反复细菌感染因此，我们研究了这些蛋白质在影响免疫反应中的作用。我们发现在由于缺乏 VPS33B，果蝇对微生物的侵害反应强烈。过度的免疫反应是响应活或死细菌而产生，以及 Toll 和 IMD 途径的纯化配体导致死亡 Vps33B 突变体，但不是野生型果蝇。 Vps33B 的这一功能在脊椎动物中是保守的，我们发现缺乏 Vps33B 的小鼠巨噬细胞在受到刺激时会分泌大量炎症细胞因子通过质膜或内体 TLR 配体。因此，我们假设模式的激活识别受体，特别是 TLR，会导致依赖于 Vps33B 的专门内体的形成用于溶酶体融合。缺乏 Vps33B 可能会影响先天性和适应性免疫的多个方面，并为了检验这一假设，我们建议 1. 定义在内体中调节 Vps33B 功能的分子事件成熟，2. 定义 Vps33B 调节的 TLR 运输和信号转导的作用 3. 研究 Vps33B 的作用 4. 研究 Vps33B 在调节抗原呈递和适应性免疫。