Adrenergic and Purinergic Regulation of Target Cells

描述（由申请方提供）：本申请是一项修订提案，旨在评估肾上腺素能受体和P2 Y嘌呤能受体信号传导的各个方面。 我们最近的初步数据包括MDCK-D1细胞中五种不同P2 Y受体的鉴定和克隆，以及ATP释放作为自分泌/旁分泌机制在这些细胞中建立基础水平信号转导的关键作用的发现。 拟议的研究将集中在MDCK-D1细胞中的研究，旨在确定有关P2 Y受体的核苷酸释放和自分泌/旁分泌信号传导、G蛋白偶联受体/G蛋白和效应分子的化学计量和区室化、肾上腺素能和P2受体激动剂促进的调节等信息。- 受体，并在平行研究中使用小鼠基因敲除，P2 Y受体和肾上腺素能受体在调节肾功能的作用。 这些研究将测试几种假设，包括以下可能性：1）核苷酸释放是多个信号转导途径的设定点的关键因素; 2）P2 Y受体、A1-AR和β 2-AR在极化MDCK细胞中的差异靶向，并产生区室化的信号微域; 3）肾上腺素能和P2 Y受体将显示“交叉调节”的证据。“后者可能有助于通过肾脏和其他细胞中的交感节后神经元调节反应。 在另外的实验中，我们将尝试确定肾上腺素能和P2的功能活性， 通过对敲除某些受体的小鼠的研究， 总的来说，这些数据应该提供新的见解上皮细胞，特别是肾上皮细胞，肾上腺素能和P2 Y受体的调节，并应有助于确定这些受体的细胞和肾脏的生理作用。 此外，这些发现可能对心血管、肾脏和其他涉及交感神经系统或细胞损伤导致核苷酸释放的疾病具有病理生理和治疗意义。

DESCRIPTION (provided by applicant): This application is a revised proposal to assess aspects of adrenergic receptor and P2Y purinergic receptor signalling. Our recent, preliminary data for this application include the identification and cloning of five different P2Y receptors in MDCK-D1 cells and discovery of a key role of ATP release as an autocrine/paracrine mechanism for establishing basal levels of signal transduction in these cells. The proposed studies will focus on studies in MDCK-D1 cells, designed to define information regarding nucleotide release and autocrine/paracrine signalling by P2Y-receptors, stoichiometry and compartmentation of G protein-coupled receptors/G protein and effector molecules, agonist-promoted regulation of adrenergic and P2-receptors, and in parallel studies using murine knockouts, the role of P2Y receptors and adrenergic receptors in regulation of renal function. The studies will test several hypotheses, including the possibilities that: 1) nucleotide release is a critical factor for the set point of multiple signal transduction pathways; 2) P2Y receptors, A1-AR and (B2-AR differentially target in polarized MDCK cells, and create compartmentalized signalling microdomains; and 3) adrenergic and P2Y receptors will show evidence of"cross regulation." The latter may contribute to modulation of response via sympathetic postganglionic neurons in the kidney and other cells. In additional experiments, we will attempt to define the functional activity of adrenergic and P2 receptors in vivo by the studies of mice with knockouts of certain receptors. Overall, the data should provide new insights into regulation of epithelial cells, in particular renal epithelial cells, by adrenergic and P2Y receptors and should help define the cell and renal physiological role of those receptors. In addition, the findings may have pathophysiologic and therapeutic implications for diseases such as cardiovascular, renal, and other disorders that involve the sympathetic nervous system or in which cell injury leads to release of nucleotides.