SIGNAL TRANSDUCTION IN SENSITIZED AIRWAY SMOOTH MUSCLE

描述：这项调查建议检查被夸大的呼吸道 狭窄反应和受损的β-肾上腺素能受体抑制反应 人类哮喘的模型。鉴于关键的细胞内秒的作用 信使、IP3在调节气道平滑肌(ASM)收缩中的作用，AS 以及某些促炎细胞因子在介导 特应性/哮喘状态，提出了两个相互关联的假设：1.改变 在收缩激动剂和β-肾上腺素能受体介导的反应性 特应性/哮喘ASM归因于受体偶联蓄积的改变 和/或IP3的作用；以及2.在 跨膜信号调节ASM反应性与FC相关 ASM中受体偶联的自分泌释放和特定细胞因子的作用。 在解释这些假说时，调节收缩能力的机制，受体 和G蛋白表达、第二信使激活和细胞因子 将在分离的兔和人ASM中检测其表达和作用 人被动致敏的组织和培养的ASM细胞 特应性/哮喘血清。研究ASM改变的机制 在敏感状态下的收缩能力，调查人员将检查 1)激动剂/受体偶联的IP3积累；2)表达的变化 和特定G蛋白的调节作用；以及3)代谢和 IP3与其钙离子动员胞内受体的结合。至 探讨β-肾上腺素受体偶联减弱的机制 致敏ASM的松弛，研究人员建议检查变化 1)特异性G蛋白表达及β-肾上腺素能调节 受体结合和转导；2)β-肾上腺素能受体/G蛋白偶联 收缩激动剂对IP3、ITS诱导蓄积的调控作用 新陈代谢及其受体结合。最后，为了解决自给自足问题 细胞因子在诱导ASM反应性改变中的作用 特应性/哮喘过敏状态，调查人员将检查1) 特应性ASM致敏诱导自分泌的表达及作用 特异性细胞因子；2)后者归因于激活 内源性上调ASM细胞表面Fc受体；3)细胞因子诱导 ASM响应性的变化反映了 上文所述目标下的单独机制。 总而言之，这些研究应该会对 ASM在Fc相互作用机制中的潜在自分泌作用 受体激活、细胞因子激活和跨膜改变 特应性/哮喘患者ASM反应性改变的信号转导 敏化状态。

DESCRIPTION: This investigation proposes to examine the exaggerated airway narrowing response and impaired beta-adrenoceptor inhibitory response in a model of human asthma. Given the role of the key intracellular second messenger, IP3 in regulating airway smooth muscle (ASM) contractility, as well as the role of certain pro-inflammatory cytokines in mediating the atopic/asthmatic state, two interrelated hypotheses are raised: 1. Changes in constrictor agonists and beta-adrenoceptor mediated responsiveness in atopic/asthmatic ASM are attributed to altered receptor coupled accumulation and/or action of IP3; and 2. The induction of these changes in transmembrane signaling regulation ASM responsiveness is related to Fc receptor-coupled autocrine release and action of specific cytokines in ASM. In addressing these hypotheses, mechanism regulating contractility, receptor and G protein expression, second messenger activation, and cytokine expression and action will be examined in isolated rabbit and human ASM tissue and cultured ASM cells passively sensitized with human atopic/asthmatic serum. To investigate mechanisms underlying altered ASM contractility in the sensitized state, the investigators will examine changes in 1) agonist/receptor-coupled accumulation of IP3; 2) expression and modulatory action of specific G proteins; and 3) the metabolism and binding of IP3 to its Ca2+ mobilizing intracellular receptor. To investigate mechanisms underlying attenuated beta-adrenoceptor-coupled relaxation in sensitized ASM, the investigators propose to examine changes in 1) specific G protein expression and regulation of beta-adrenergic receptor biding and transduction; and 2) beta-adrenoceptor/G protein-coupled modulation of constrictor agonist-induced accumulation on IP3, its metabolism, and its receptor binding. Finally, to address the autorcrine role of cytokines in inducing altered ASM responsiveness in the atopic/asthmatic sensitized state, the investigators will examine whether 1) atopic sensitization of ASM induces the autocrine expression and action of specific cytokines; 2) the latter is attributed to activation of endogenously upregulated Fc receptors on ASM cells; and 3) cytokine-induced changes in ASM responsiveness reflect alterations in the contributions of the separate mechanisms delineated above under objectives cited above. Collectively, these studies should yield important new insights into the potential autocrine role of ASM in the mechanistic interplay between Fc receptor activation, cytokine activation, and altered transmembrane signaling contributing to altered ASM responsiveness in the atopic/asthmatic sensitized state.