Modeling Beta2 receptor activity in cellular environment

细胞环境中 Beta2 受体活性的建模

• 批准号: 6961771
• 负责人: THOMAS C RICH
• 金额: $ 2.13万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-15 至 2005-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6961771
• 关键词: Adenoviridae; beta adrenergic receptor; biological signal transduction; biosensor device; calcium flux; cardiac myocytes; cell surface receptors; chemical kinetics; confocal scanning microscopy; cyclic AMP; diffusion; enzyme activity; enzyme inhibitors; forskolin; green fluorescent proteins; laboratory rat; manganese; mathematical model; membrane channels; newborn animals; phosphodiesterases; prostaglandin E; protein kinase A; single cell analysis; tissue /cell culture; transfection /expression vector

DESCRIPTION (provided by applicant): Changes in cyclic AMP (cAMP) levels transmit information to downstream effectors including protein kinase A (PKA) and cyclic nucleotide-gated (CNG) channels. In turn, these enzymes regulate such diverse cellular responses as Ca2+ influx, excitability, and gene expression. It is accepted that the localization and frequency content of cAMP signals help to orchestrate a wide variety of cellular functions, yet little is known about either the sub-cellular localization or dynamics of these signals. The overall goal of this project is to elucidate the molecular and cellular mechanisms that localize cAMP signals, the frequency content of cAMP signals, and the potential roles of cAMP oscillations in cellular function. Addressing these issues will require an innovative approach for measuring cAMP levels in single cells and. To this end, we have developed high-resolution cAMP sensors based on genetically-engineered CNG channels. These sensors measure cAMP signals near the surface membrane with unprecedented spatial and temporal resolution. The following Specific Aims outline a plan to apply this approach to study the sub-cellular localization and frequency content of cAMP signals in neonatal cardiac myocytes. Aim 1. Determine which PDE types regulate cAMP signals triggered by different agents and how inhibition of different PDE types affects the kinetics of cAMP signals. Aim 2. Determine the relative contributions of diffusional barriers, PDE activity, and buffering by PKA in localizing cAMP signals. Aim 3. Develop mathematical models describing the spatial spread and kinetics of cAMP signals throughout the cell. Aim 4. Develop integrated mathematical models of the activation and desensitization of beta2ARs in the cellular environment. The proposed studies are particularly relevant in cardiac myocytes. The intimate relationships between beta-adrenergic signaling, cAMP production, cardiac excitability, and disease are well documented. However, there is a great deal of controversy surrounding the roles of beta1- and beta2-adrenergic receptors, 'switching', differential activation of Gs and Gi, and compartmentation of responses. Measuring single-cell, cAMP signals triggered by agents that activate specific GPCRs (e.g., beta2-adrenergic receptors) or inhibit phosphodiesterase activity will shed new light on the physiologic functions of these enzymes and their relation to cardiac function. Importantly, the development of integrated mathematical models that accurately describe beta2-adrenergic receptor desensitization will give us a better understanding of the impact of pharmacological agents such as beta-blockers, inverse agonists, and asthma drugs on signaling networks and cellular physiology.

描述（由申请人提供）： 环状AMP（CAMP）水平的变化将信息传输到下游效应子，包括蛋白激酶A（PKA）和环状核苷酸门控通道。反过来，这些酶调节了CA2+流入，兴奋性和基因表达等各种细胞反应。人们认为，cAMP信号的本地化和频率含量有助于协调各种细胞功能，但对于这些信号的亚细胞定位或动力学知之甚少。该项目的总体目标是阐明定位cAMP信号的分子和细胞机制，cAMP信号的频率含量以及cAMP振荡在细胞功能中的潜在作用。解决这些问题将需要一种创新的方法来测量单个单元格中的营地水平。为此，我们基于基于遗传学的CNG通道开发了高分辨率cAMP传感器。这些传感器以前所未有的空间和时间分辨率测量表面膜附近的cAMP信号。以下特定目的概述了采用这种方法来研究新生儿心肌细胞中营地信号的亚细胞定位和频率含量的计划。目标1。确定哪种PDE类型调节由不同试剂触发的营地信号，以及对不同PDE类型的抑制如何影响营地信号的动力学。 AIM 2。确定PKA在定位营地信号中的扩散屏障，PDE活动和缓冲的相对贡献。目标3。开发数学模型，描述整个细胞中cAMP信号的空间扩散和动力学。目标4。开发β2AR在细胞环境中激活和脱敏的综合数学模型。拟议的研究在心肌细胞中尤其重要。 β-肾上腺素能信号传导，营地产生，心脏兴奋性和疾病之间的亲密关系已得到充分记录。然而，围绕beta1-和beta2-肾上腺素能受体的作用，“切换”，GS和GI的差异激活以及反应的分室的作用存在很多争议。测量单细胞，由激活特定GPCR（例如β2-肾上腺素受体）或抑制磷酸二酯酶活性的药物触发的cAMP信号将为这些酶的生理功能及其与心脏功能的关系提供新的启示。重要的是，准确描述β2-肾上腺素受体脱敏的综合数学模型的发展将使我们更好地了解药理学剂，例如β受体阻滞剂，反激动剂和哮喘药物对信号网络和细胞生理学的影响。