LOCAL REGULATION OF AIRWAY SMOOTH MUSCLE TONE

气道平滑肌张力的局部调节

基本信息

批准号：
6184980
负责人：
CAROL A HIRSHMAN
金额：
$ 28.71万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
1998
资助国家：
美国
起止时间：
1998-09-01 至 2002-08-31
项目状态：
已结题

项目摘要

Airway smooth muscle (ASM) contraction is a critical component in the pathophysiology of airway disease. Parasympathetic efferent nerves, mast cells, eosinophils and epithelial cells all release or synthesize substances that modify ASM tone. Although a rise in the intracellular calcium concentration is the normal trigger for smooth muscle contraction, agonist activation renders the myofilaments more sensitive to calcium (Ca2+) and potentiates Ca2+-induced contraction. Agonist activation, moreover, dynamically reorganizes the cytoskeleton. Preliminary studies for this proposal indicate that small G proteins (rho and ras) are important regulators of agonist-activated potentiation of Ca2+-induced contraction and cytoskeletal reorganization in ASM. However, the signaling pathways which link agonist activation via the heterotrimeric and small G proteins to cytoskeletal reorganization and potentiation of Ca2+-induced contraction in ASM are not well understood. Hence our overall goal is to determine how the signalling pathways transduced by the heterotrimeric G proteins, Gq and Gi, regulate the small G proteins, rho and ras, in ASM. We hypothesize that in ASM, activation of Gi is linked to rho, whereas activation of Gq is linked to ras. Using physiological, biochemical, and molecular techniques, we propose to: a) evaluate the signalling pathways by which activation of Gi and Gq induce rho- and ras-mediated potentiation of Ca2+-induced contraction in skinned porcine ASM, b) to identify the pathways by which Gq- and Gi-coupled receptor activation of rho increases formation of actin filaments and phosphorylation of paxillin in intact porcine ASM and cultured human ASM cells, and c) to examine the intermediate steps in the pathways linking Gi- and Gq-coupled receptors to ras and rho in cultured ASM. An understanding of signaling pathways in ASM regulating these novel Ca2+ independent processes that increase force production promises new targets and improved methods for the treatment of airway disease.

气道平滑肌 (ASM) 收缩是气道平滑肌 (ASM) 收缩的关键组成部分气道疾病的病理生理学。副交感传出神经，肥大细胞、嗜酸性粒细胞和上皮细胞均释放或合成改变 ASM 音调的物质。虽然细胞内钙浓度是平滑肌的正常触发因素收缩，激动剂激活使肌丝更加敏感与钙 (Ca2+) 结合并增强 Ca2+ 诱导的收缩。激动剂此外，激活会动态重组细胞骨架。该提案的初步研究表明，小 G 蛋白（rho 和 ras）是激动剂激活增强作用的重要调节因子 ASM 中 Ca2+ 诱导的收缩和细胞骨架重组。然而，通过连接激动剂激活的信号通路异三聚体和小 G 蛋白对细胞骨架重组和 Ca2+ 诱导 ASM 收缩的增强作用尚不清楚。因此，我们的总体目标是确定信号通路如何由异源三聚体 G 蛋白 Gq 和 Gi 转导，调节 ASM 中的小 G 蛋白、rho 和 ras。我们假设在 ASM 中， Gi 的激活与 rho 相关，而 Gq 的激活与 rho 相关至拉斯。利用生理学、生化和分子技术，我们建议：a) 评估信号通路，通过该通路激活 Gi 和 Gq 诱导 rho 和 ras 介导的 Ca2+ 诱导的增强作用去皮猪 ASM 的收缩，b) 以确定其收缩的途径 rho 的 Gq 和 Gi 偶联受体激活可增加完整猪 ASM 中的肌动蛋白丝和桩蛋白磷酸化并培养人类 ASM 细胞，c) 检查中间步骤在连接 Gi 和 Gq 偶联受体与 ras 和 rho 的途径中培养的 ASM。了解 ASM 调节中的信号通路这些新颖的独立于 Ca2+ 的过程可增加力量的产生承诺治疗气道的新目标和改进方法疾病。