Membrane trafficking in innate immunity to bacterial pathogens

膜运输对细菌病原体的先天免疫

基本信息

批准号：
10238030
负责人：
Adriana Rita Mantegazza
金额：
$ 39万
依托单位：
THOMAS JEFFERSON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-14 至 2023-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10238030
关键词：
1-Phosphatidylinositol 4-Kinase Anti-Bacterial Agents Anti-Inflammatory Agents Antibacterial Response Antigen Presentation Antigens Attention Autophagocytosis Bacteria Bacterial Infections Binding CD4 Positive T Lymphocytes Cell membrane Cell surface Cells Chloride Channels Complex Cytoplasmic Receptors Data Defect Dendritic Cells Detection Disease model Endosomes Environment Enzymes FRAP1 gene Family Genetic Diseases Hermanski-Pudlak Syndrome Homeostasis Human Immune Immune System Diseases Immune response Immunity Immunologic Deficiency Syndromes Immunologic Receptors Impairment Inflammasome Inflammatory Inflammatory Response Innate Immune Response Interleukin-1 Ion Channel Lead Link Lipids Lysosomes Membrane Membrane Transport Proteins Modeling Molecular Natural Immunity Nature Nucleoside Transporter Nutrient Oligopeptides Organelles Outcome Particulate Pathway interactions Pattern Phagocytes Phagosomes Phosphatidylinositols Play Positioning Attribute Process Production Property Protein Sortings Receptor Signaling Regulation Role Sentinel Signal Transduction Site Sorting - Cell Movement Stimulus TIRAP gene TLR4 gene Testing Toll-like receptors Vesicle adaptive immune response adaptive immunity cytokine fighting inorganic phosphate microbial mouse model novel pathogen pathogenic bacteria phosphatidylinositol 4-phosphate protein transport rare genetic disorder recruit response trafficking

项目摘要

SUMMARY Anti-bacterial inflammatory responses in phagocytes are initiated by recognition of common pathogen associated molecular patterns (PAMPs) by innate immune receptors. PAMP binding to membrane-associated toll-like receptors (TLRs) at distinct subcellular sites triggers site-specific responses, and bacteria that compromise phagosomal membranes additionally trigger cytoplasmic receptors, some of which assemble into multisubunit inflammasomes that process and release IL-1 family cytokines. Membrane dynamics within host phagocytes dramatically influence TLR and inflammasome localization and signaling, but host regulation of such dynamics has been relatively unexplored. Our studies in a genetic disease model identified the endosomal adaptor complex AP-3 as a central hub for intracellular trafficking pathways that regulate both TLR and inflammasome responses to phagocytosed bacteria in dendritic cells (DCs) - immune cells that link innate responses to adaptive immunity. However, AP-3 impacts these responses indirectly, reflecting AP-3's central role in endolysosomal protein sorting. We hypothesize that defining direct targets of AP-3 sorting will elucidate new membrane pathways controlling innate signaling and downstream anti-bacterial immune responses. AP-3 sorts cargoes on endosomes into vesicles bound for lysosomes, phagosomes or related organelles. We hypothesize that innate signaling defects in AP-3-deficient DCs reflect depletion of AP-3 cargoes from these organelles. Preliminary data suggest that one such cargo is PI4K2α, an enzyme that generates the lipid phosphatidylinositol-4-phosphate to recruit TLRs via their proinflammatory adaptors to membranes. Aim 1 will test whether phagosomal PI4K2α recruits TLRs to initiate pro-inflammatory signaling and antigen presentation. Other putative AP-3 cargoes include lysosomal transporters that function in lysosome homeostasis. We hypothesize that depletion of such cargoes triggers a lysosome-dependent signaling cascade that promotes inflammasome silencing by autophagy. Aim 2 will test whether and how lysosomal disruption impacts inflammasome activity, and Aim 3 will test whether depletion of specific candidate lysosomal membrane channels similarly silence inflammasomes and impact lysosome signaling and adaptive immune responses. Fulfillment of the following Specific Aims will elucidate novel pathways that are potentially targeted by genetic disease and/or by pathogen interference to compromise host immunity to bacterial pathogens. 1. To test whether TLR signaling from phagosomes and downstream responses are regulated by the AP-3-associated PtdIns-4-kinase PI4K2α. 2. To test whether impaired lysosomal function dampens inflammasome activity through nutrient- dependent signaling. 3. To test whether lysosomal membrane transporter expression influences inflammasome activation.

概括吞噬细胞中的抗菌炎症反应是通过识别常见病原体引发的与先天免疫接收器相关的分子图案（PAMP）。 pamp结合与膜相关的在不同的亚细胞部位的收费样受体（TLR）触发特异性反应和细菌折衷的吞噬体膜还触发细胞质受体，其中一些受体组装成处理和释放IL-1家族细胞因子的多亚基炎症体。主机内的膜动力学吞噬细胞动态影响TLR和炎症体的定位和信号传导，但宿主调节这样的动态相对出乎意料。我们在遗传疾病模型中的研究确定了内体适配器复合物AP-3作为调节两个TLR的细胞内运输途径的中心枢纽以及对树突状细胞中吞噬细菌（DCS）的炎症反应 - 将先天性联系起来的免疫细胞对适应性免疫学的反应。但是，AP-3间接影响这些响应，反映了AP-3的中心在内溶性蛋白质分类中的作用。我们假设定义AP-3排序的直接目标将阐明控制先天信号和下游抗细菌免疫调查的新膜途径。 AP-3将货物上的货物分类为融合的溶酶体，吞噬体或相关细胞器的蔬菜。我们假设AP-3缺陷DC中的先天信号缺陷反映了AP-3货物的消耗细胞器。初步数据表明，这样的货物是PI4K2α，一种生成脂质的酶磷脂酰肌醇-4-磷酸盐通过其促炎的膜到膜上募集TLR。目标1意志测试吞噬体PI4K2α食谱是否会启动促炎信号传导和抗原表现。其他推定的AP-3货物包括在溶酶体稳态中起作用的溶酶体转运蛋白。我们假设此类货物的依赖会触发促溶酶体依赖性信号级联自噬的炎症体沉默。 AIM 2将测试溶酶体干扰是否以及如何影响炎性体活动和AIM 3将测试特定候选溶酶体膜的耗尽通道类似地沉默炎症，并影响溶酶体信号传导和适应性免疫调查。实现以下特定目标将阐明遗传可能针对的新型途径疾病和/或通过病原体干扰可损害细菌病原体的宿主免疫学。 1。测试来自吞噬体和下游响应的TLR信号是否由 AP-3相关的PTDINS-4-激酶PI4K2α。 2。为了测试受损的溶酶体功能是否通过营养抑制了炎症体活性 - 依赖的信号传导。 3。测试溶酶体膜转运蛋白表达是否会影响炎症体激活。