Gene regulatory mechanisms and neurogenic airway inflammation

基因调控机制与神经源性气道炎症

• 批准号: 6504189
• 负责人: GEORGES E. HADDAD
• 金额: $ 24.81万
• 依托单位: HOWARD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2002-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6504189
• 关键词: asthma; biological signal transduction; bronchomotion; cooperative study; guinea pigs; inflammation; neuroimmunomodulation; neuropeptide receptor; respiratory hypersensitivity; respiratory muscles; smooth muscle; tachykinin

Bronchial asthma is associated with inflammatory changes, swelling, stiffness of the airways, spontaneous, mechanically or chemically evoked bronchoconstriction. These changes can be initiated and maintained by autonomic imbalance in bronchodilatory and bronchoconstrictive influences. In this grant proposal we will stress how the nervous system via a number of differentiated patterns during prolonged and often repeated stimulations, affect airway structure and functions down to cellular and molecular level of organization. In particular, the role of sensory innervation will be studied. Subsets of sensory fibers, both in animals and humans, contain the tachykinin peptides, substance P (SP) and neurokinin A (NKA), which are colocalized with calcitonin gene related peptide (CGRP). In response to noxious agents and bradykinin (BK), SP, NKA and CGRP are released from sensory nerves and when released they exert a variety of local biological effects, including increase in cholinergic transmission, airway smooth muscle (ASM) contraction, mucus secretion and plasma protein extravasation. These changes are mediated through activation of typical features of bronchial asthma. We hypothesize that in bronchial asthma the regulation of the NK-1, NK-2, and NK-3 receptors in achieved via a feedforward mechanism in which peptide synthesis or secretion (or both) is enhanced. Increased levels of released SP and NKA would then cause increased in the expression and the sensitivity of NK-1, NK-2, and NK-3 receptors, and potentiate cholinergic influences. We will investigate changes in SPK, BK and NKA levels, NK-1, NK-2, CGRP, B-1 and B-2 receptor mRNAs and receptor peptide expression in airways of asthmatics and in the airways of sensitized guinea pigs following repeated exposure to antigen. Preprotachykinin (PTT) mRNA expression in the airways will be quantitated using solution hybridization-nuclease protection assays. Peptide and receptor mRNA expression levels will be normalized to glyceraldehyde-3- phosphatedydrogenase mRNA levels. Similarly, expression of the BK receptor message and receptor protein will be determined in guinea pigs. In the airway smooth muscle preparation, the link between changes in signal transduction pathways and airway hyper- responsiveness will be studied. Using biophysical and biochemical approaches, we will assess the changes in contractility of the airway smooth muscle which could account for the refractoriness to therapy by employing techniques well established in our laboratories. The results of proposed studies will contribute to better understanding of fundamental mechanisms of a feedforward system as a determinant of progression of the pathologic process, and will lead to improved methods in treatment of obstructive airway disorders.

支气管哮喘与炎症变化、肿胀、气道僵硬、自发性、机械性或化学性诱发的支气管收缩有关。这些变化可以通过支气管扩张和支气管收缩影响的自主神经失衡来启动和维持。在这项拨款提案中，我们将强调神经系统如何在长期且经常重复的刺激过程中通过多种不同的模式影响气道结构和功能，直至组织的细胞和分子水平。特别是，将研究感觉神经支配的作用。动物和人类的感觉纤维亚群都含有速激肽、P 物质 (SP) 和神经激肽 A (NKA)，它们与降钙素基因相关肽 (CGRP) 共定位。为了响应有害物质和缓激肽 (BK)，感觉神经会释放 SP、NKA 和 CGRP，释放后它们会发挥多种局部生物效应，包括增加胆碱能传递、气道平滑肌 (ASM) 收缩、粘液分泌和血浆蛋白外渗。这些变化是通过激活支气管哮喘的典型特征来介导的。我们假设，在支气管哮喘中，NK-1、NK-2 和 NK-3 受体的调节是通过前馈机制实现的，其中肽合成或分泌（或两者）均得到增强。释放的 SP 和 NKA 水平增加会导致 NK-1、NK-2 和 NK-3 受体的表达和敏感性增加，并增强胆碱能影响。我们将研究重复暴露后哮喘患者气道和致敏豚鼠气道中 SPK、BK 和 NKA 水平、NK-1、NK-2、CGRP、B-1 和 B-2 受体 mRNA 和受体肽表达的变化至抗原。使用溶液杂交-核酸酶保护测定法对气道中的前速激肽 (PTT) mRNA 表达进行定量。肽和受体 mRNA 表达水平将标准化为 3-磷酸甘油醛酶 mRNA 水平。类似地，将在豚鼠中测定 BK 受体信息和受体蛋白的表达。在气道平滑肌准备中，将研究信号转导途径的变化与气道高反应性之间的联系。使用生物物理和生化方法，我们将评估气道平滑肌收缩力的变化，这可以通过采用我们实验室成熟的技术来解释治疗的难治性。拟议研究的结果将有助于更好地理解前馈系统作为病理过程进展的决定因素的基本机制，并将导致阻塞性气道疾病治疗方法的改进。