Purinergic receptors in inflammation

炎症中的嘌呤能受体-趋化作用允许中性粒细胞(PMN) 以迅速到达感染和发炎的部位。然而，PMN的过度内流会损害宿主组织。更好 了解控制中性粒细胞趋化的机制可能会改善炎症性疾病的治疗 疾病。根据我们最近的发现，三磷酸腺苷和腺苷参与了中性粒细胞的趋化作用，我们提出 在这里研究如何调节这种嘌呤能信号传递过程，以防止组织损伤。嘌呤能 信号有三个基本组成部分：i)细胞外ATP和腺苷的来源；ii)嘌呤能 对ATP和腺苷作出反应的受体，以及，iii)通过以下方式调节细胞反应的胞外核苷酸酶 将三磷酸腺苷分解为腺苷。这项建议基于以下工作假设： 趋化剂从中性粒细胞释放三磷酸腺苷。ATP激活附近的P2Y2受体，放大梯度 感官。A3腺苷受体被招募到CD39/E-产生腺苷的前沿 NTPDase1和碱性磷酸酶(ALP)。腺苷和A3受体正反馈驱动细胞 迁移，而通过A2a受体的负反馈促进了细胞背面的膜回缩。 干扰这些嘌呤能信号传递过程会抑制趋化作用，从而改善PMN诱导的趋化作用 脓毒症和创伤患者的组织损伤和器官衰竭。 将实现以下具体目标： 1.中性粒细胞释放三磷酸腺苷的机制：本节将重点介绍中性粒细胞释放的机制。 细胞内的ATP对趋化刺激的反应。具体地说，我们将重点关注 HTTYH3微调最大阴离子通道、连接蛋白半通道和脱颗粒。 2.腺苷形成机制：实验旨在研究主要的胞外核苷酸酶 负责将释放的三磷酸腺苷转化为腺苷。主要的重点将放在 NTPDase1和ALP的贡献。 3.嘌呤能信号复合体：我们将探索趋化受体与三磷酸腺苷的共存 释放部位、嘌呤能受体和胞外核苷酸酶，并研究嘌呤能信号簇， 由这些分子组成，提供了理论上提出的“局部激发和全局抑制”。 趋化模型。 4.嘌呤能信号在体内的作用：我们将研究P2Y2、A3、A2a、NTPDase1和ALP在体内的作用 并测试以这些分子为靶点以防止宿主组织损伤的可行性。 这些拟议的研究有望提高我们对控制趋化性的机制的理解。 这可能导致新的治疗方法来改善过度流入造成的宿主组织损伤 例如，在创伤和感染性休克患者中，激活的PMN的数量。叙述性 趋化性是中性粒细胞在健康和疾病中的一个关键功能反应，目前对其了解甚少。在这 我们提出的项目是确定细胞ATP和嘌呤能受体的释放如何控制趋化性和 这种控制机制是否可以通过药物靶向来预防炎症和宿主组织 创伤患者的损害。

PURINERGIC RECEPTORS IN INFLAMMATION - Chemotaxis allows polymorphonuclear neutrophils (PMN) to rapidly reach infected and inflamed sites. However excessive influx of PMN damages host tissues. Better knowledge of the mechanisms that control PMN chemotaxis may lead to improved treatments of inflammatory diseases. Based on our recent findings that ATP and adenosine are involved in PMN chemotaxis, we propose to study here how to regulate this purinergic signaling process in order to prevent tissue damage. Purinergic signaling has three essential components: i) sources of the extracellular ATP and adenosine; ii) purinergic receptors that response to ATP and adenosine and, iii) ecto-nucleotidases that modulate cellular responses by hydrolyzing ATP to adenosine. This proposal is based on the following working hypothesis: Chemotactic agents release ATP from PMN. ATP activates nearby P2Y2 receptors, amplifying gradient sensing. A3 adenosine receptors are recruited to the leading edge where adenosine is generated by CD39/E- NTPDase1 and alkaline phosphatase (ALP). Adenosine and positive feedback through A3 receptors drives cell migration, while negative feedback through A2a receptors facilitates membrane retraction at the back of cells. Interfering with these purinergic signaling processes inhibits chemotaxis, which ameliorates PMN-induced tissue damage and organ failure in sepsis and trauma patients. The following specific aims will be addressed: 1. Mechanism of ATP release from PMN: This section will focus on the mechanisms by which PMN release cellular ATP in response to chemotactic stimulation. Specifically, we will focus on the involvement of hTTYH3 tweety maxi-anion channels, connexin hemi-channels, and degranulation. 2. Mechanism of adenosine formation: Experiments are designed to examine the major ecto-nucleotidases that are responsible for the conversion of released ATP to adenosine. Major emphasis will be placed on the contributions of NTPDase1 and ALP. 3. Purinergic signaling complexes: We will explore the co-localization of chemotactic receptors with ATP release sites, purinergic receptors, and ecto-nucleotidases and investigate if purinergic signaling clusters, comprised of these molecules provide "local excitation and global inhibition" as proposed in theoretical chemotaxis models. 4. Role of purinergic signaling in vivo: We will study the roles of P2Y2, A3, A2a, and NTPDase1 and ALP in mouse models and test the feasibility of targeting these molecules to prevent host tissue damage. The proposed studies are expected to improve our understanding of the mechanisms that control chemotaxis. This could lead to novel therapeutic approaches to ameliorate host tissue damage caused by excessive influx of activated PMN, for example, in trauma and septic shock patients. Narrative Chemotaxis, a key functional response of neutrophils in health and disease is still poorly understood. In this project we propose to determine how release of cellular ATP and purinergic receptors control chemotaxis and whether this control mechanism can be pharmacologically targeted to prevent inflammation and host tissue damage in trauma patients.