Sweet receptor (T1R2/3) signaling in the upper airway and regulation of immunity

上呼吸道中的甜味受体 (T1R2/3) 信号转导和免疫调节

• 批准号: 8958191
• 负责人: Robert J. Lee
• 金额: $ 16万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8958191
• 关键词: ASIC channel; Acidity; Acute; Affect; Amino Acids; Anti-Bacterial Agents; Antibodies; Artificial Sweeteners; Bacteria; Bacterial Infections; Bicarbonates; Biochemistry; Biological Assay; Breathing; Cell Culture Techniques; Cell physiology; Cells; Chronic; Consumption; Coupled; Coupling; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Data; Diabetes Mellitus; Effectiveness; Epithelial Cells; Epithelium; Functional disorder; Future; GTP-Binding Proteins; Genetic; Genetic Polymorphism; Genotype; Glucose; Goals; Health; Homo; Human; Immune response; Immunity; Immunofluorescence Immunologic; Immunofluorescence Microscopy; Infection; Irrigation; Lead; Left; Life; Ligands; Link; Measurement; Mediating; Metabolism; Microbial Biofilms; Modeling; Mus; Natural Immunity; Nitric Oxide; Nose; Pathway interactions; Patients; Pattern; Play; Predisposition; Production; Protein Isoforms; Publishing; Regulation; Relative (related person); Research; Respiratory Tract Infections; Role; Signal Pathway; Signal Transduction; Signal Transduction Pathway; T1R receptor; T2R taste receptors; TRPM5 gene; Taste Buds; Taste Perception; Techniques; Testing; Therapeutic; Time; Tissues; Tongue; Upper Respiratory Infections; Western Blotting; airway epithelium; airway surface liquid; antimicrobial peptide; bactericide; cell type; cellular imaging; chronic rhinosinusitis; defense response; high throughput screening; in vivo; inhibitor/antagonist; insight; prevent; public health relevance; quorum sensing; rat Gnat3 protein; receptor; research study; response; sugar; sweet receptor; sweet taste perception; taste transduction; therapeutic target

 DESCRIPTION (provided by applicant): We recently discovered that human sinonasal solitary chemosensory cells (SCCs) express T2R bitter taste receptors that, when activated, stimulate Ca2+ -driven secretion of antimicrobial peptides (AMPs) from surrounding epithelial cells, playing an important role in innate immunity. We hypothesize that, in vivo, SCCs use T2Rs to respond to bitter bacterial products by activating AMP secretion. Furthermore, SCC T2R-mediated Ca2+ responses are inhibited the T1R3 sweet receptor in response to artificial sweeteners, sweet D-amino acids (produced by many bacteria), and physiologically-relevant glucose concentrations in the airway surface liquid (ASL). This inhibition may occur through T1R-activation of cAMP signaling. Immunofluroescence suggests that T2R and T1R3 receptors are expressed within the same SCCs, likely coupled to different intracellular signaling pathways. We hypothesize that T1R-mediated inhibition of T2Rs exists to partially inhibit AMP release during times of relative health, as complete secretion and depletion of AMPs may leave the epithelium excessively vulnerable. During acute infection, bacteria may consume available ASL glucose, decreasing glucose concentration and deactivating T1R inhibition of T2Rs, allowing AMP release. The ability of T1Rs to inhibit AMP secretion is also modulated by airway surface liquid (ASL) pH, which may represent a host adaptive mechanism to counter D-amino acid production by bacteria. While we have defined much of human SCC T2R signaling, this T1R pathway is unknown. Our central hypothesis is that T1R2 and/or T1R3 sweet receptor subunits and T2Rs, expressed in the same sinonasal SCCs, are coupled to different intracellular signaling pathways. To test this, we will take sinonasal tissue explants and differentiated primary cultures of human and mouse sinonasal cells and (1) use immunofluorescence to examine T1R distribution in human SCCs, (2) identify T1R signal transduction pathway(s) in SCCs, including deriving pure or enriched cultures of mouse SCCs to biochemically characterize SCC T1R signaling, and (3) examine the mechanism of ASL pH regulation of SCC T1R signaling. We will also genotype human Tas1R2 and Tas1R3 polymorphisms to determine their influence on T1R signaling in SCCs. The goal of these aims is to identify the localization and signal transduction of sinonasal T1R receptors, which may be very important to developing new therapies for respiratory infections. ASL glucose is abnormally elevated in certain conditions such as diabetes mellitus and chronic rhinosinusitis, both of which often involve chronic respiratory infections. Excessive ASL glucose may overly inhibit T2R-mediated innate immunity, making T1R antagonists (eg, lactisole) therapeutic options to restore innate immune responses in certain patients. Moreover, if Tas1R2/3 polymorphisms play an important role in sinonasal T1R function, then future studies could reveal that Tas1R genetics and/or taste testing may be useful for making predictions about susceptibility to upper respiratory infections and/or the effectiveness of T1R-targeted therapeutics.

 描述(申请人提供)：我们最近发现人类鼻窦孤立化学感觉细胞(SCCs)表达T2R苦味受体，当被激活时，刺激周围上皮细胞由钙离子驱动的抗菌肽(AMPs)的分泌，在先天免疫中发挥重要作用。我们假设，在体内，SCC使用T2Rs通过激活AMP分泌来对苦味细菌产物做出反应。此外，人工甜味剂、甜味D-氨基酸(由许多细菌产生)以及呼吸道表面液体(ASL)中与生理相关的葡萄糖浓度都会抑制T1R3甜味受体对SCC T2R介导的钙离子反应。这种抑制可能是通过激活cAMP信号的T1R来实现的。免疫荧光显示，T2R和T1R3受体在同一个SCCs中表达，可能与不同的细胞内信号通路有关。我们假设，在相对健康的时期，存在T1R介导的抑制T2Rs的存在，以部分抑制AMP的释放，因为AMP的完全分泌和耗尽可能会使上皮过于脆弱。在急性感染期间，细菌可能会消耗有效的ASL葡萄糖，降低葡萄糖浓度，使T1R抑制T2Rs失活，从而允许AMP释放。T1Rs抑制AMP分泌的能力也受到呼吸道表面液体(ASL)pH的调节，这可能是宿主适应对抗细菌产生D-氨基酸的机制。虽然我们已经定义了人类SCC T2R信号的大部分，但T1R途径尚不清楚。我们的中心假设是，T1R2和/或T1R3甜味受体亚基和T2R在相同的鼻腔鼻窦SCCs中表达，连接到不同的细胞内信号通路。为了验证这一点，我们将以人和小鼠鼻窦组织块和分化的原代培养的人鼻窦细胞为研究对象，(1)利用免疫荧光技术检测T1R在人鼻腔鳞状细胞中的分布，(2)确定T1R信号转导途径(S)，包括获得纯或浓缩的小鼠SCCs培养物，以对SCC T1R信号的生化特征进行研究，以及(3)研究ASL pH调节SCC T1R信号的机制。我们还将对人类Tas1r2和TAS1R3基因多态进行分型，以确定它们对SCC中T1R信号的影响。这些目标的目的是确定鼻窦T1R受体的定位和信号转导，这可能对开发呼吸道感染的新疗法非常重要。在某些情况下，如糖尿病和慢性鼻窦炎，ASL血糖会异常升高，这两种情况通常都涉及慢性呼吸道感染。过量的ASL葡萄糖可能会过度抑制T2R介导的天然免疫，使T1R拮抗剂(如乳酸)成为某些患者恢复天然免疫反应的治疗选择。此外，如果Tas1r2/3基因多态性在鼻腔T1R功能中起重要作用，那么未来的研究可能会揭示Tas1R遗传学和/或味觉测试可能有助于预测上呼吸道感染的易感性和/或T1R靶向治疗的有效性。