SEROTONIN (5-HT) AND 5-HT2A IN ALLERGIC INFLAMMATION

血清素 (5-HT) 和 5-HT2A 在过敏性炎症中的作用

• 批准号: 6969505
• 负责人: P. SRIRAMARAO
• 金额: $ 46.64万
• 依托单位: LA JOLLA INST FOR MOLECULAR MEDICINE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-03 至 2009-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6969505
• 关键词: biological signal transduction; bronchoscopy; cell adhesion; cell migration; chemoattractants; chemokine; chemokine receptor; chemotaxis; confocal scanning microscopy; disease /disorder model; eosinophil; eosinophilia; genetically modified animals; human subject; inflammation; laboratory mouse; laboratory rabbit; pulmonary circulation; receptor expression; respiratory hypersensitivity; serotonin; serotonin inhibitor; serotonin receptor; vascular endothelium

DESCRIPTION (provided by applicant): Chemoattractants play a critical role in the activation and directed migration of eosinophils to extravascular sites of allergic inflammation. Recently published studies from our laboratory have shown for the first time that serotonin (5-hydroxytryptamine [5-HT]) can directly induce chemotaxis of eosinophils, but not neutrophils, and play an important role in the recruitment of eosinophils in a murine model of allergic inflammation. 5-HT both independently and additively with eotaxin induces eosinophil chemotaxis in vitro and in vivo. Preliminary studies suggest that eosinophils from allergic donors but not control subjects express the 5-HT2A receptor. Furthermore, both 5-HT induced eosinophil chemotaxis in vitro and allergen induced eosinophil recruitment in wild type and eotaxin-/- mice could be inhibited by the 5-HT2A receptor antagonists cyproheptadine and MDL-100907. Based on these findings, we hypothesize that 5-HT, functioning via the 5-HT2A receptor, is a novel eosinophil-active chemoattractant that plays an important role in eosinophil recruitment and overall pathogenesis of allergic inflammation. To evaluate our hypotheses, in Specific Aim 1, we will evaluate the role played by the 5-HT and 5-HT2A receptor pathway in mediating various aspects of allergic inflammation including eosinophil recruitment, airway hyperreactivity (AHR), Th1/Th2 cytokines and airway remodeling. We will evaluate the effect of the 5-HT2A receptor antagonist MDL-100907 in the presence and absence of a CCR3 antagonist in a murine model of allergic airway inflammation in wild type and T-bet-/- mice as well as 5-HT2A-/- and CCR3-/- mice. The importance of the additive effect of 5-HT2A and CCR3 will be examined in greater detail by generating a 5-HT2A-/-/7CCR3-/- double knock mouse. In Specific Aim 2, we will study the effect of the 5-HT2A receptor antagonist on eosinophil trafficking under condition of flow. In addition, we will utilize intravital microscopy (IVM) to examine how murine eosinophils isolated from IL-5trg mice traffic within 5-HT stimulated lung microvessels using a novel murine lung allograft model. To further examine the role of 5-HT on vascular endothelium mediated eosinophil trafficking, lung tissue from OVA-challenged 5-HT2A-/- mice will be used in the lung allograft model. Moreover, our studies have delineated important differences and similarities in the signaling pathways that mediate 5-HT (p160 ROCK) versus eotaxin (Gai) induced chemotaxis. As part of the second aim, we will examine the role of these signaling molecules to determine the points of divergence and convergence between the 5-HT2A- and CCR3-mediated pathways. Overall, we propose to examine in detail the cellular and molecular mechanisms that participate in 5-HT-mediated allergic inflammation and hypothesize that blockade of 5-HT2A receptor individually or in combination with the CCR3 receptor might lead to alleviation of airway allergic inflammation including eosinophil recruitment, AHR, Th1/Th2 cytokines and airway remodeling.

描述（由申请人提供）：化学引诱剂在嗜酸性粒细胞的激活和定向迁移至过敏性炎症的血管外部位中发挥关键作用。我们实验室最近发表的研究首次表明，血清素（5-羟色胺[5-HT]）可以直接诱导嗜酸性粒细胞趋化，但不能诱导中性粒细胞趋化，并且在过敏性炎症小鼠模型中的嗜酸性粒细胞募集中发挥重要作用。 5-HT 独立地或与嗜酸性粒细胞趋化因子相加，在体外和体内诱导嗜酸性粒细胞趋化性。初步研究表明，来自过敏性供体的嗜酸性粒细胞表达 5-HT2A 受体，但对照受试者不表达。此外，5-HT2A 受体拮抗剂赛庚啶和 MDL-100907 均可抑制体外 5-HT 诱导的嗜酸性粒细胞趋化性以及野生型和嗜酸性粒细胞趋化因子-/- 小鼠中过敏原诱导的嗜酸性粒细胞募集。基于这些发现，我们假设通过 5-HT2A 受体发挥作用的 5-HT 是一种新型嗜酸性粒细胞活性化学引诱剂，在嗜酸性粒细胞募集和过敏性炎症的总体发病机制中发挥重要作用。为了评估我们的假设，在具体目标 1 中，我们将评估 5-HT 和 5-HT2A 受体途径在介导过敏性炎症各个方面所发挥的作用，包括嗜酸性粒细胞募集、气道高反应性 (AHR)、Th1/Th2 细胞因子和气道重塑。我们将在野生型和 T-bet-/- 小鼠以及 5-HT2A-/- 和 CCR3-/- 小鼠的过敏性气道炎症小鼠模型中评估 5-HT2A 受体拮抗剂 MDL-100907 在存在和不存在 CCR3 拮抗剂的情况下的效果。将通过生成 5-HT2A-/-/7CCR3-/- 双敲击小鼠来更详细地检查 5-HT2A 和 CCR3 相加效应的重要性。在具体目标2中，我们将研究5-HT2A受体拮抗剂对流动条件下嗜酸性粒细胞运输的影响。此外，我们将利用活体显微镜 (IVM) 来检查从 IL-5trg 小鼠中分离出的鼠嗜酸性粒细胞如何在 5-HT 刺激的肺微血管内使用新型鼠肺同种异体移植模型。为了进一步研究 5-HT 对血管内皮介导的嗜酸性粒细胞运输的作用，来自 OVA 攻击的 5-HT2A-/- 小鼠的肺组织将用于肺同种异体移植模型。此外，我们的研究已经描述了介导 5-HT (p160 ROCK) 与嗜酸细胞趋化因子 (Gai) 诱导的趋化性的信号通路的重要差异和相似性。作为第二个目标的一部分，我们将检查这些信号分子的作用，以确定 5-HT2A 和 CCR3 介导的途径之间的分歧点和收敛点。总体而言，我们建议详细检查参与 5-HT 介导的过敏性炎症的细胞和分子机制，并假设单独阻断 5-HT2A 受体或与 CCR3 受体联合阻断可能会减轻气道过敏性炎症，包括嗜酸性粒细胞募集、AHR、Th1/Th2 细胞因子和气道重塑。