MEDIATORS, AIRWAY SMOOTH MUSCLE GROWTH AND CONTRACTILITY

哮喘的特点是支气管炎症，气道平滑肌 增生和增强的非特异性气道收缩。 基于 新出现的证据支持平滑肌 增生和增强激动剂介导的平滑肌收缩，两个 提出了相关假设：I：炎症细胞介质 产生支气管收缩也是生长诱导性的， 肌肉;和II：气道平滑肌增生的诱导是 与激动剂介导的气道平滑肌改变相关 收缩性 在解决这些假设时，增殖反应， 激动剂介导的收缩反应，以及调节细胞- 将在培养兔中检测表面受体表达和结合 气道平滑肌（ASM）细胞。 答：评估相互关系 炎症细胞介质、ASM生长和ASM改变之间的关系 收缩性，我们将研究：1）是否支气管活性 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 内皮细胞衍生的肽，内皮素，每一个都翻转一个 在培养的ASM细胞中的增殖作用与 原癌基因c-myc和c-fos; 2）是否增殖ASM细胞 描述了激动剂介导的收缩反应性的改变， 细胞内游离钙和收缩细胞大小的变化 分布 后者将通过荧光测量来确定， 负载钙敏感染料Fura-2的细胞和ASM的分析 使用库尔特计数器技术的细胞尺寸分布曲线， 分别B：评估收缩功能改变的潜在机制 在增生的ASM细胞中，我们将研究：1）是否 增殖的ASM细胞表现出受体密度的变化， 毒蕈碱胆碱能和β-肾上腺素能的配体结合亲和力 受体;和2）ASM细胞生长相关的变化是否 毒蕈碱胆碱能和β-肾上腺素能受体结合护理生长- 毒蕈碱胆碱能和β-肾上腺素能受体的相关变化 结合与这些基因编码的mRNA的量的调节偶联， 受体及其基因转录速率。 后者将 通过北方印迹分析和核流出研究评估， 分别 总的来说，拟议中的研究应该提供新的机制见解 炎症细胞介质、气道 平滑肌增生和气道收缩力改变， 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.