Basis of Variability of Lung GPCR Signaling

描述（由申请人提供）：肺中的许多主要信号事件都是由g蛋白偶联受体（gpcr）超家族进行的。这些包括支气管平滑肌松弛和收缩、粘液分泌、纤毛搏动频率、炎症、免疫细胞运输、肺血管张力和通透性、肺泡液体和电解质运输，以及许多尚未确定的功能。据估计，大约有75种gpcr在人肺中表达。在未来五年内，绝大多数治疗药物将以gpcr为靶点。然而，GPCR信号的生理、病理和药理学行为显示出大量的个体间差异，这被认为是由于编码这些受体的基因的共同变异（多态性）。据估计，这种多态性在对靶向gpcr的治疗性激动剂和拮抗剂反应的变异性中占50%。事实上，仅用一种GPCR（2-肾上腺素能受体），我们已经表明，编码和启动子多态性改变了体外细胞中受体的表达、功能和调节，在哮喘患者中，它们与临床表型和对β激动剂治疗的反应有关。本提案的长期目标是鉴定多达20个肺GPCR基因的多态性，并通过使用重组表达技术来描述它们对与肺内稳态和病理生物学相关的细胞信号传导的生化和药理学影响。在Aim 1中，这20个GPCR基因的多态性将在60个不同种族个体的基因组DNA样本的启动子、5‘非翻译区、编码区、内含子/外显子连接区和3’非翻译区进行描述。在目标2中，多态性（单倍型）的常见组合将被描述在人群中。在目标3中，将开发构建物并模拟用于重组GPCR单倍型表达的细胞系统，以确定多态性对受体表达、信号传导或调控的生物学效应。这些研究将为哮喘、肺动脉高压、肺炎、肺纤维化、慢性阻塞性肺病和肺水肿等多种肺部疾病的个体间易感性和治疗反应性、病理生物学的变异性以及开发新的治疗策略提供基础。

DESCRIPTION (provided by applicant): Many major signaling events in the lung are carried out by the superfamily of G-protein coupled receptors (GPCRs). These include bronchial smooth muscle relaxation and contraction, mucous secretion, ciliary beat frequency, inflammation, immune cell trafficking, pulmonary vascular tone and permeability, and alveolar fluid and electrolyte transport, as well as many yet to be defined functions. Approximately 75 GPCRs are estimated to be expressed in human lung. Within the next five years, the great majority of all therapeutic agents will target GPCRs. However, the physiologic, pathologic, and pharmacologic behavior of GPCR signaling displays substantial interindividual variability which is thought to be due to common variants (polymorphisms) of the genes encoding these receptors. Such polymorphisms have been estimated to account for as much as 50% of the variability in the response to therapeutic agonists and antagonists targeted to GPCRs. Indeed, with just one GPCR, the (2-adrenergic receptor, we have shown that coding and promoter polymorphisms alter receptor expression, function, and regulation in vitro in cells, and in asthmatic patients, they are associated with clinical phenotypes and the response to beta-agonist therapy. The long-term goals of this proposal are to identify polymorphisms of up to 20 pulmonary GPCR genes, and by the use of recombinant expression techniques to delineate their biochemical and pharmacologic impact on cellular signaling relevant to lung homeostasis and pathobiology. In Aim 1, the polymorphisms of these 20 GPCR genes will be delineated in the promoter, 5' untranslated, coding, intron/exon junctions, and 3' untranslated regions from genomic DNA samples from a cohort of 60 ethnically diverse individuals. In Aim 2, the common combinations of polymorphisms (haplotypes) will be delineated in the population. In Aim 3, constructs will be developed and model cell systems utilized for recombinant expression of GPCR haplotypes to determine the biological effects of polymorphisms on receptor expression, signaling, or regulation. These studies will provide the basis for interindividual susceptibility and therapeutic responsiveness, the variability in pathobiology, and the potential for developing new treatment strategies, for a diverse range of lung diseases including asthma, pulmonary hypertension, pneumonia, pulmonary fibrosis, COPD, and pulmonary edema.