Dynamic Calcium Regulation in Airway Smooth Muscle

描述（由申请人提供）：哮喘是一种炎性疾病，其中TH 2（如IL-13）和促炎（如TNF α）细胞因子诱导气道平滑肌（ASM）功能异常，导致气道高反应性（AHR），这是该疾病的标志。炎性细胞因子改变平滑肌的钙信号传导和收缩性，导致对激动剂的高反应性。我们实验室的研究表明，CD 38/Cyclic ADP-核糖信号通路在ASM的钙调节中起着重要作用，并且该信号通路通过NF-？B和AP-1以及转录稳定性。参与该调节的信号传导机制由PI 3激酶和促分裂原活化蛋白激酶（MAPK）的活化介导。缺乏CD 38的小鼠表现出以乙酰甲胆碱反应性减弱为特征的气道表型。来自这些小鼠的ASM细胞对激动剂的钙反应也降低。虽然这些观察结果表明CD 38参与了正常气道功能，但其在哮喘病理生理学中的潜在作用仍有待确定。在ASM细胞中，CD 38的表达被细胞因子增强，而糖皮质激素（哮喘治疗的主要药物）可降低这种表达。初步结果显示，CD 38缺陷小鼠在IL-13或过敏原致敏和激发后表现出减弱的AHR。通过骨髓移植重建CD 38 +/+炎性细胞进入CD 38缺陷小鼠，恢复AHR对过敏原的攻击。这些研究首次涉及哮喘中的CD 38/环ADP-核糖信号通路，并提出了该提案中概述的细胞/组织中CD 38表达调节机制的生理意义。本研究的目的是阐明参与CD 38表达调控的信号机制，并确定CD 38在AHR气道平滑肌细胞和炎症细胞中的作用。总体假设是细胞因子通过PI 3激酶激活、下游MAPK信号传导和NF-κ B活化来调节ASM中CD 38的表达。B和AP-1，并且气道驻留细胞中的CD 38/环ADP-核糖信号传导足以引起由炎症反应引起的AHR。糖皮质激素的作用是通过抑制MAPK和转录因子的活化以及转录物的稳定性来介导的。在拟议的研究中，我们将确定特定的机制，CD 38调节的炎症和TH 2细胞因子在ASM和在体内的意义，这些机制在小鼠实验性哮喘模型。这一新的信息可能将CD 38确定为预防和控制哮喘的潜在药理学靶点。我们认为，气道中的CD 38/环ADP-核糖信号通路的调节剂应该能够保护哮喘等疾病的气道高反应性。公共卫生相关性。哮喘是一种炎症性疾病，患者气道平滑肌对刺激的反应过度。细胞因子如IL-13和TNFa在哮喘的发病机制中具有核心作用。缺乏蛋白质CD 38的小鼠不会对细胞因子的攻击产生哮喘反应。我们建议研究CD 38在气道中的表达如何受细胞因子的调节，并建立其在不同小鼠哮喘模型中的作用。这一新的信息可能将CD 38确定为预防和控制哮喘的潜在药理学靶点。

DESCRIPTION (provided by applicant): Asthma is an inflammatory disease in which TH2 (such as IL-13) and proinflammatory (such as TNFa) cytokines induce abnormalities of airway smooth muscle (ASM) function that causes airway hyperresponsiveness (AHR), a hallmark of this disease. Inflammatory cytokines alter calcium signaling and contractility of ASM which results in hyperreactivity to agonists. Investigations from our laboratory have provided evidence that the CD38/Cyclic ADP-ribose signaling has a central role in calcium regulation in ASM and this signaling pathway is regulated by TH2 and proinflammatory cytokines through transcriptional mechanisms involving NF-?B and AP-1 and transcript stability. The signaling mechanisms involved in this regulation are mediated by activation of PI3 kinases and Mitogen-activated Protein Kinases (MAPK). Mice deficient in CD38 exhibit an airway phenotype characterized by attenuated methacholine responsiveness. ASM cells from these mice also have reduced calcium responses to agonists. While these observations implicate CD38 in normal airway function, its potential role in the pathophysiology of asthma remains to be determined. In ASM cells, CD38 expression is augmented by cytokines, and glucocorticoids, a mainstay of asthma therapy, decrease this expression. Preliminary results reveal that CD38 deficient mice exhibit attenuated AHR following IL-13 or allergen sensitization and challenge. Reconstitution of CD38+/+ inflammatory cells by bone marrow transfer into CD38 deficient mice restores AHR to allergen challenge. These studies are the first to implicate the CD38/Cyclic ADP-ribose signaling pathway in asthma and bring a physiological significance of the mechanisms of regulation of CD38 expression in cells/tissues outlined in the proposal. The goal of the proposed studies is to delineate the signaling mechanisms involved in the regulation of CD38 expression and to define the role of CD38 in airway smooth muscle cells and inflammatory cells in AHR. The overall hypothesis is that cytokines regulate CD38 expression in ASM through PI3 kinase activation, down-stream MAPK signaling and activation of NF-?B and AP-1, and that the CD38/Cyclic ADP-ribose signaling in airway resident cells is sufficient to cause AHR resulting from the inflammatory response. Glucocorticoid effects are mediated through inhibition of MAPK and transcription factor activation, and transcript stability. In the proposed studies, we will determine specific mechanisms of CD38 regulation by inflammatory and TH2 cytokines in ASM and the in vivo significance of these mechanisms in mouse models of experimental asthma. This new information may identify CD38 as a potential pharmacological target in the prevention and control of asthma. We propose that modulators of the CD38/Cyclic ADP-ribose signaling pathway in the airways should afford protection from airway hyperresponsiveness in diseases such as asthma. PUBLIC HEALTH RELEVANCE. Asthma is an inflammatory disease in which patients have exaggerated airway smooth muscle response to stimuli. Cytokines such as IL-13 and TNFa have a central role in the pathogenesis of asthma. Mice deficient in a protein, CD38, do not develop an asthmatic response to challenges with cytokines. We are proposing to study how the expression of CD38 in the airways is regulated by cytokines and establish its role in different mouse models of asthma. This new information may identify CD38 as a potential pharmacological target in the prevention and control of asthma.