Basis of Variability of Lung GPCR Signaling

描述（由申请人提供）：肺中的许多主要信号传导事件由G蛋白偶联受体（GPCR）超家族进行。 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、肺血管张力和渗透性、肺泡液体和电解质运输，以及许多尚未定义的功能。 估计约75种GPCR在人肺中表达。 在未来五年内，绝大多数治疗药物将靶向GPCR。 然而，GPCR信号传导的生理、病理和药理学行为显示出很大的个体间变异性，这被认为是由于编码这些受体的基因的常见变体（多态性）。 据估计，这种多态性占对靶向GPCR的治疗性激动剂和拮抗剂的反应的变异性的50%。 事实上，仅用一种GPCR，β-肾上腺素能受体，我们已经证明编码和启动子多态性改变细胞中的受体表达、功能和体外调节，并且在哮喘患者中，它们与临床表型和对β-激动剂治疗的反应相关。 该提案的长期目标是确定多达20个肺GPCR基因的多态性，并通过使用重组表达技术来描述其对与肺稳态和病理生物学相关的细胞信号传导的生物化学和药理学影响。 在目的1中，这20个GPCR基因的多态性将在来自60个种族多样性个体的组群的基因组DNA样品的启动子、5'非翻译区、编码区、内含子/外显子连接区和3'非翻译区中描绘。 在目标2中，将在人群中描述多态性（单倍型）的常见组合。 在目标3中，将开发用于重组表达GPCR单倍型的构建体和模型细胞系统，以确定多态性对受体表达、信号传导或调节的生物学效应。 这些研究将为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的潜力提供基础，用于各种肺部疾病，包括哮喘、肺动脉高压、肺炎、肺纤维化、COPD和肺水肿。

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.