MEDIATORS, AIRWAY SMOOTH MUSCLE GROWTH AND CONTRACTILITY

哮喘的特点是支气管炎、气道平滑肌 增生，非特异性气道收缩功能增强。基于 新出现的证据支持血管平滑肌之间的联系 增殖和增强激动剂介导的平滑肌收缩，两个 相关的假说被提出：I：炎性细胞介质 它们会引起支气管收缩，也会导致呼吸道通畅 肌肉；以及II：诱导气道平滑肌增生是 与激动剂介导的气道平滑肌改变相关 伸缩性。在回答这些假设时，增殖性反应， 激动剂介导的收缩反应，以及调节细胞- 将检测培养兔的表面受体表达和结合 呼吸道平滑肌(ASM)细胞。答：为了评估相互关系 炎症细胞介质、ASM生长和改变的ASM之间的关系 收缩功能，我们将调查：1)支气管是否活跃 介质：组胺、白三烯C4和D4、前列腺素D2、血小板 活化因子、嗜酸性粒细胞衍生的主要碱性蛋白P物质和 内皮细胞衍生的多肽，内皮素，每一种都是 血管紧张素转换酶基因表达改变对体外培养的ASM细胞增殖的影响 原癌基因c-myc和c-fos；2)ASM细胞是否增殖 描述了改变的激动剂介导的收缩反应性，由 细胞内游离钙和收缩细胞大小的变化 分发。后者将通过荧光测量确定 钙敏感染料Fura-2负载细胞及ASM分析 使用库尔特计数器技术的细胞尺寸分布曲线， 分别进行了分析。B：评估收缩功能改变的机制 在增生的ASM细胞中的反应性，我们将调查：1)是否 增殖的ASM细胞表现出受体密度和 毒碱-胆碱能和β-肾上腺素能的配基结合亲和力 受体；以及2)ASM细胞生长相关的变化 毒碱-胆碱能和β-肾上腺素能受体结合的CARE生长 毒碱-胆碱能和β-肾上腺素能受体的相关变化 结合与为这些基因编码的信使核糖核酸的数量的调节相耦合 受体及其基因转录速率。后者将是 通过Northern印迹分析和核径流研究进行评估， 分别进行了分析。 总的来说，拟议的研究应提供新的机械论见解 探讨炎性细胞介质与呼吸道的相互关系 平滑肌增生和呼吸道收缩功能改变是其基础 哮喘的发病机制。

Asthma is characterized by bronchial inflammation, airway smooth muscle hyperplasia, and enhanced non-specific airway contractility. Based on emerging evidence in support of an association between smooth muscle hyperplasia and enhanced agonist-mediated smooth muscle contraction, two interrelated hypotheses are raised: I: That inflammatory cell mediators which produce bronchonstriction are also growth inductive to airway smooth muscle; and II: That induction of airway smooth muscle hyperplasia is associated with altered agonist-mediated airway smooth muscle contractility. In addressing these hypotheses, proliferative responses, agonist-mediated contractile responses, and mechanisms regulating cell- surface receptor expression and binding will be examined in cultured rabbit airway smooth muscle (ASM) cells. A: To assess the interrelationship between inflammatory cell mediators, ASM growth, and altered ASM contractility, we will investigate: 1) whether the bronchoactive mediators: histamine, leukotrienes C4 and D4, prostaglandin D2, platelet activating factor, eosinophil-derived major basic protein substance P, and the endothelial cell-derived peptide, endothelin, each everts a proliferative effect in cultured ASM cells coupled to altered expression of the protooncogenes, c-myc and c-fos; and 2) whether proliferating ASM cells depict altered agonist-mediated contractile responsiveness, given by changes in intracellular free-calcium and contractile cell size distribution. The latter will be determine by fluorescence measurement of cells loaded with the calcium-sensitive dye, fura-2 and analysis of ASM cell size distribution curves using the Coulter counter technique, respectively. B: To assess mechanisms underlying altered contractile reponsiveness in hyperplastic ASM cells, we will investigate: 1) whether proliferating ASM cells exhibit changes in the receptor densities and ligand-binding affinities of the muscarinic-cholinergic and beta-adrenergic receptors; and 2) whether ASM cell growth-associated changes in muscarinic-cholinergic and beta-adrenergic receptor binding care growth- associated changes in muscarinic-cholinergic and beta-adrenergic receptor binding are coupled to modulation in the quantities of mRNA coded for these receptors and their rates of gene transcription. The latter will be assessed by Northern blot analysis and nuclear run-off studies, respectively. collectively, the proposed studies should provide new mechanistic insights into the interrelationship between inflammatory cell mediators, airway smooth muscle hyperplasia, and altered airway contractility which underlies the pathogenesis of asthma.