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（由申请人提供）：我们最近发现人鼻窦孤立化学感应细胞（SCC）表达 T2R 苦味受体，当激活时，刺激 Ca2+ 驱动的周围上皮细胞分泌抗菌肽（AMP），在我们勇敢地承认，在体内，SCC 使用 T2R 通过激活 AMP 分泌来对苦味细菌产物做出反应。 SCC T2R 介导的 Ca2+ 反应会抑制 T1R3 甜味受体对人工甜味剂、甜味 D-氨基酸（由许多细菌产生）和气道表面液体 (ASL) 中生理相关葡萄糖浓度的反应。这种抑制可能通过以下方式发生。 cAMP 信号传导的 T1R 激活表明 T2R 和 T1R3 受体在相同的 SCC 中表达，可能与不同的细胞内信号传导途径偶联。预先警告，在相对健康的时期，T1R 介导的 T2R 抑制会部分抑制 AMP 的释放，因为 AMP 的完全分泌和耗尽可能会使上皮细胞在急性感染期间过于脆弱，细菌可能会消耗可用的 ASL 葡萄糖，从而降低葡萄糖浓度并失活。 T1R 抑制 T2R，从而允许 AMP 释放 T1R 抑制 AMP 分泌的能力也受气道表面液体 (ASL) pH 值的调节，这可能代表宿主适应性机制。虽然我们已经定义了许多人类 SCC T2R 信号传导，但我们的中心假设是 T1R2 和/或 T1R3 甜味受体亚基和 T2R 在相同的鼻腔 SCC 中表达，为了测试这一点，我们将采取鼻腔组织外植体和人和小鼠鼻腔细胞的分化原代培养物，并（1）使用免疫荧光。检查人类 SCC 中的 T1R 分布，(2) 鉴定 SCC 中的 T1R 信号转导途径，包括衍生小鼠 SCC 的纯培养物或富集培养物以生化表征 SCC T1R 信号传导，以及 (3) 检查 ASL pH 调节机制我们还将对人类 Tas1R2 和 Tas1R3 多态性进行基因分型，以确定它们对 SCC 中 T1R 信号传导的影响。确定鼻腔 T1R 受体的定位和信号转导，这对于开发呼吸道感染的新疗法可能非常重要。 ASL 葡萄糖在某些情况下异常升高，例如糖尿病和慢性鼻窦炎，这两种情况通常都涉及慢性呼吸道感染。 ASL 葡萄糖可能会过度抑制 T2R 介导的先天免疫，从而使 T1R 拮抗剂（例如，lactisole）成为恢复某些患者先天免疫反应的治疗选择。 Tas1R2/3 多态性在鼻腔 T1R 功能中发挥重要作用，因此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。