Immune function of bitter taste receptors in human macrophages

项目总结 T2R苦味受体是最初在舌头上发现的G蛋白偶联受体(GPCRs)， 但它们在其他组织中也起着不同的作用。“口外”(舌外)味觉感受器很可能 对呼吸道感染、哮喘、早产，甚至癌症都很重要。在呼吸道上皮细胞中，T2R4，14， 16和38识别由革兰氏阴性细菌产生的群体感应分子，包括 条件致病菌铜绿假单胞菌。对这些受体的刺激改变了 抗菌分子，包括一氧化氮和防御素。一些降低功能的多态 T2Rs增加了患者对上呼吸道感染和慢性鼻窦炎的易感性。靶向T2R 因为治疗需要更好地阐明它们的表达和下游效应。这一点必须在 原代人类细胞，因为小鼠T2Rs的数量和激活它们的激动剂不同。 我们在原代人单核细胞和巨噬细胞中发现了几种T2R受体。巨噬细胞 是重要的先天免疫细胞，吞噬和杀灭细菌，并分泌亲或抗 调节免疫反应的炎性细胞因子。刺激这些受体可激活钙释放 一氧化氮的产生能显著(在5-15分钟内)增强细菌的吞噬作用。初步数据 提示T2Rs可能是刺激先天免疫反应以杀灭细菌而不使用 常规抗生素，减少抗生素耐药性的压力。这可能在上一页中特别有用 呼吸道疾病。急性和慢性鼻-鼻窦炎占所有抗生素处方的20%。 因此是抗药性微生物的重要驱动力。慢性鼻-鼻窦炎和 在许多患者中，相关的鼻息肉还会导致嗅觉障碍、嗅觉障碍和/或嗅觉障碍。 我们将进一步定义促进巨噬细胞吞噬的信号通路，并测试它是如何 影响细菌杀灭(目标1)。因为像铜绿假单胞菌这样的细菌可以侵入细胞并以细胞内的形式生存 为了逃避进一步的免疫检测，我们将测试T2Rs如何影响巨噬细胞的杀菌活性。 这项工作还将是第一批使用活细胞成像和荧光生物传感器来研究巨噬细胞的工作之一。 实时发送GPCR信号。接下来(目标2)，我们将研究T2R激活如何减少炎症 对Toll样受体(TLRs)的反应。我们的初步数据表明了T2R-TLR串扰的新途径 可能牵涉到阿克。最后(目标3)我们将比较表型、T2R表达和T2R功能。 炎症性慢性鼻窦炎鼻息肉的巨噬细胞与幼稚血清来源的巨噬细胞 同样的病人。我们将检查息肉的巨噬细胞浸润是否因T2R基因多态或 苦味知觉。我们还检查鼻息肉中巨噬细胞数量的增加是否会影响慢性鼻息肉 鼻-鼻窦炎疾病表型。

PROJECT SUMMARY T2R bitter taste receptors are G-protein coupled receptors (GPCRs) originally identified on the tongue, but which also serve diverse roles in other tissues. “Extraoral” (outside the tongue) taste receptors are likely important in airway infection, asthma, pre-term labor, and even cancer. In airway epithelial cells, T2Rs 4, 14, 16, and 38 recognize quorum-sensing molecules produced by gram-negative bacteria, including the opportunistic pathogen Pseudomonas aeruginosa. Stimulation of these receptors modifies production of antibacterial molecules, including nitric oxide and defensins. Some polymorphisms reducing the functionality of T2Rs increase patient susceptibility to upper respiratory infection and chronic rhinosinusitis. Targeting T2Rs as therapies requires better elucidation of their expression and downstream effects. This must be studied in primary human cells, as mouse T2Rs differ in number and agonists that activate them. We identified several T2R receptors in primary human monocytes and macrophages. Macrophages are important innate immune cells that phagocytose and kill bacteria as well as secrete pro- or anti- inflammatory cytokines to modify immune responses. Stimulation of these receptors activates calcium release and nitric oxide production that acutely (within 5-15 min) enhances phagocytosis of bacteria. Preliminary data suggest that T2Rs may be targets for stimulation of innate immune responses to kill bacteria without the use of conventional antibiotics, reducing pressures for antibiotic resistance. This may be especially useful in upper respiratory diseases. Acute and chronic rhinosinusitis account for >20% of all antibiotic prescriptions in the US, and thus are important drives of antibiotic resistant micro-organisms. Chronic rhinosinusitis and associated nasal polyps also cause dysosmia, hyposmia, and/or anosmia in many patients. We will further define the signaling pathway that increases macrophage phagocytosis and test how it affects bacterial killing (Aim 1). As bacteria such as P. aeruginosa can invade cells and live as intracellular pathogens to evade further immune detection, we will test how T2Rs affect macrophage bactericidal activity. This work will also be among the first to use live cell imaging and fluorescent biosensors to study macrophage GPCR signaling in real time. Next (Aim 2), we will examine how T2R activation reduces inflammatory responses to toll-like receptors (TLRs). Our preliminary data suggest novel pathways of T2R-TLR crosstalk possibly involving Akt. Finally (Aim 3) we will compare phenotype, T2R expression, and T2R function in macrophages from inflamed chronic rhinosinusitis nasal polyps with naïve serum-derived macrophages from the same patients. We will examine if macrophage infiltration of polyps is altered with T2R polymorphisms or bitter taste perception. We also examine if increased macrophage numbers in nasal polyps affects chronic rhinosinusitis disease phenotypes.