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Therapy for bronchial asthma by regulating a small G protein as a targeting molecule

通过调节小G蛋白作为靶向分子治疗支气管哮喘

基本信息

批准号：
17590785
负责人：
KUME Hiroaki
金额：
$ 2.3万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17590785/
关键词：
Rho β-adrenergic receptors S1P eosinophil airway smooth muscle airway hyperresponsiveness airway remodeling oxidative stress Rho-kinase 細胞増殖 Ca^<2+>感受性スタチン気管支喘息好酸球浸潤 IL-5 ケモカイン G_i

项目摘要

This project was designed to determine whether Rho, a small G protein, is useful to therapy for bronchial asthma as a targeting molecule. Since Rho, and it's effector enzyme, Rho-kinase, have functional relevance for Ca^<2+> sensitization, cell proliferation, cell migration, and cytoskeleton, the Rho/Rho-kinase pathway may related to eosinophil infiltration, airway hyperresponsiveness, β-adrenergic desensitization, and airway remodeling which are pathophysiogy of bronchial asthma. Isometric tension and concentrations of intracellular Ca^<2+> [Ca^<2+>]_i were simultaneously measured using fura-2 loaded tracheal smooth muscle in guinea pigs. When isoproterenol, a β-adrenergic receptor agonist, was cumulatively applied to the tissues precontracted with 1 μM methacholine, isoproterenol caused an inhibition of contraction induced by methacholine with reducing [Ca^<2+>]_i in a concentration-dependent manner. However, a reduction in tension was greater than that in [Ca^<2+>]_i in the inhibito … More ry action of isoproterenol, indicating that β-adrenergic action antagonizes not only Ca^<2+> mobilization but also Ca^<2+> sensitization. Loss of the latter process leads to dysfunction of β-adrenergic receptors. Hydrogen peroxide, an indicator of oxidative stress, generated force with elevating [Ca^<2+>]_i. However, Y-27632, an inhibitor of Rho-kinase, inhibited contraction by hydrogen peroxide without reducing [Ca^<2+>]_i, indicating that airflow limitation by oxidative stress is associated with activation of Rho-kinase. After exposure to sphingosine 1-phosphate (S1P), a bioactive lysophospholipid released from inflammatory cells, methacholine-induced contraction was markedly enhanced without elevating [Ca^<2+>]_i, and Y-27632 antagonized the augmented responsiveness to methacholine by pretreatment with S1P. Airway hyperresponsiveness is mediated by Rho-induced Ca^<2+> sensitization via inactivation of myosin phosphatase. In cultured human bronchial smooth muscle cells, cell proliferation and DNA synsethsis induced by FBS was inhibited by simvastatin, a HMG-CoA reductase, and Y-27632. Rho/Rho-kinase activity regulated by the mevalonate pathways in cholesterol synthesis contributes to cell proliferation related to airway remodeling. In sensitize mice, antigen challenges caused eosinophil infiltration to airways and an increase in the lung resistance in response to methacholine. Administration of Y-27632 and fasudil, another inhibitor of Rho-kinase, inhibited eosinophilia and augmented lung resistance by antigens challenges. The Rho/Rho-kinase pathway is involved in the airway inflammation by eosinophil recruitment.In conclusion, inhibiting the Rho/Rho-kinase pathway may have therapeutic potential for bronchial asthma. Less

该项目旨在确定Rho是一种小G蛋白，作为靶向分子是否对哮喘的治疗有用。由于Rho及其效应酶Rho-K与细胞的钙致敏、细胞增殖、细胞迁移和细胞骨架等功能相关，因此Rho/Rho-K通路可能与嗜酸性粒细胞浸润、气道高反应性、β-肾上腺素能脱敏和气道重塑等哮喘的病理生理机制有关。用Fura-2负荷法同时测定豚鼠气管平滑肌等长张力和细胞内钙离子浓度。当β受体激动剂异丙肾上腺素累积应用于1μM乙酰甲胆碱预收缩的组织时，异丙肾上腺素可抑制乙酰胆碱引起的收缩，并呈浓度依赖性地降低[Ca~(2+)&gt；]_i。然而，在抑制剂…中，张力的降低大于[Ca^&lt；2+]_i异丙肾上腺素的作用更强，说明β-肾上腺素能作用不仅拮抗Ca~(2+)动员，而且还能拮抗Ca~(2+)敏化。后一过程的缺失会导致β-肾上腺素能受体功能障碍。过氧化氢是氧化应激的指标，随着[Ca^&lt；2+&gt；]_i的升高而产生作用力。然而，Rho-Kinase的抑制剂Y-27632抑制过氧化氢的收缩而不降低[Ca^&lt；2+&gt；]_i，这表明氧化应激对气流的限制与Rho-Kinase的激活有关。1-磷酸鞘氨醇(S1P)是一种从炎性细胞释放的生物活性溶血磷脂，暴露于S1P后，乙酰胆碱引起的收缩明显增强，而不升高[Ca~(2+)]_i，Y-27632可拮抗S1P对乙酰胆碱的增强反应性。Rho通过肌球蛋白磷酸酶失活诱导的Ca^&lt；2+和gt；敏化介导了气道高反应性。HMG-CoA还原酶辛伐他汀和Y-27632对培养的人支气管平滑肌细胞增殖和DNA合成均有抑制作用。在胆固醇合成过程中，Rho/Rho-Kinase活性受甲氧戊酸途径调节，参与与气道重塑相关的细胞增殖。在致敏小鼠中，抗原攻击导致嗜酸性粒细胞渗入呼吸道，并增加了对乙酰甲胆碱的肺抵抗力。给予Y-27632和另一种Rho-Kinase抑制剂法舒地尔，可抑制嗜酸性粒细胞增多，并通过抗原攻击增强肺抵抗。Rho/Rho-Kinase通路通过嗜酸性粒细胞聚集参与了气道炎症，抑制Rho/Rho-Kinase通路可能对哮喘有治疗潜力。较少