Regulation of CFTR by adenosine, A2 receptors, and PLA2

描述(摘自申请者的摘要)：囊性纤维化 以呼吸道上皮离子转运缺陷为特征，细菌 感染，以及强烈的以白细胞为主的炎症。加在一起，这些 过程有助于渐进性的呼吸道破坏 这种疾病。CFTR的突变启动了这种级联反应，创造了一种异常的 呼吸道表面液体微环境。而离子中Cf特有的异常 运输和炎症已被描述，目前正处于激烈的 研究表明，调节呼吸道微环境的因素 CF呼吸道疾病的两个基本方面都没有明确的认识。 腺苷是一种内源性自糖皮质激素，是一种有吸引力的候选分子， 激活跨越呼吸道和其他表达CFTR的上皮细胞的C1分泌，以及 调节白细胞的许多重要方面(中性粒细胞和巨噬细胞) 功能。证据还表明，呼吸道上皮细胞和炎性细胞 细胞输出腺苷核苷酸，这些核苷酸在细胞外代谢 环境对腺苷的影响。细胞信号主要是通过腺苷传递的 受体，包括A2受体。这项提议的目的是为了 炎症调节剂腺苷如何通过A2受体激活CFTR。 我们的初步结果表明，A2受体通过 磷脂酶A2(PLA2)和花生四烯酸。这条信号通路代表着 一种新的，以前没有描述过的调节CFTR活性的机制。这个 这项提案中概述的研究将：(1)表征A2受体的激活 依赖CFTR的氯在活细胞和呼吸道上皮细胞中的转运 活体，(2)确定腺苷是否是呼吸道中的主要核苷酸 微环境，以及(3)帮助制定和测试战略，以改善 野生型cftr活性的检测及突变体功能的改进 体外和体内CFTRs。腺苷信号转导提供了一个新的框架 考虑上皮细胞和免疫系统之间的相互作用 在呼吸道微环境中，帮助弥合 炎症、CFTR和氯离子分泌。概述的实验还发现了一个 调控CFTR的新方法，因此可能有助于确定新的治疗靶点 在疾病中。

DESCRIPTION(adapted from applicant's abstract): Cystic fibrosis is characterized by defective epithelial ion transport in the airways, bacterial infection, and intense, leukocyte-dominated inflammation. Together, these processes contribute to the progressive airway destruction characteristic of the disease. Mutations in CFTR initiate this cascade, creating an abnormal airway surface liquid microenvironment. While CF-specific abnormalities in ion transport and inflammation have been described and are currently under intense investigation, the factors within the airway microenvironment that modulate both fundamental aspects of CF airway disease are not clearly identified. Adenosine is an endogenous autocoid that is an attractive candidate molecule, activating C1- secretion across airway and other CFTR-expressing epithelia, and modulating many important aspects of leukocyte (neutrophil and macrophage) function. Evidence also suggests that both airway epithelia and inflammatory cells export adenosine nucleotides which are metabolized in the extracellular environment to adenosine. Cellular signaling is primarily through adenosine receptors, including A2 receptors. This proposal is intended to characterize how the inflammatory regulator adenosine, through A2 receptors, activates CFTR. Our preliminary results suggest that A2 receptors activate CFTR through phospholipase A2 (PLA2) and arachidonic acid. This signaling pathway represents a novel, previously undescribed mechanism to modulate CFTR activity. The studies outlined in this proposal will: (1) characterize A2 receptor activation of CFTR-dependent Cl transport in living cells and across airway epithelia in vivo, (2) determine whether adenosine is a predominant nucleotide in the airway microenvironment, and (3) help to develop and test strategies to improve the detection of wildtype CFTR activity, and to improve the function of mutant CFTRs in vitro and in vivo. Adenosine signaling provides a new framework in which to consider the interactions between the epithelia and immune system within the airway microenvironment, helping to bridge the gap between inflammation, CFTR, and Cl- secretion. The experiments outlined also identify a new way to regulate CFTR, and therefore may help define new therapeutic targets in the disease.