Sympathetic Outflow to Catecholamine Storage Vesicles

描述（由申请人提供）： 在高血压中，节后交感神经和嗜铬细胞的传出交感神经活动增加，导致血管收缩、钠潴留和血压升高。 嗜铬粒蛋白/分泌粒蛋白（嗜铬粒蛋白A [Cga].嗜铬粒蛋白B [Cgb]。和分泌颗粒蛋白II [SgII]是在胺和肽激素和神经递质分泌囊泡的核心中发现的酸性蛋白质家族，例如嗜铬颗粒和节后交感神经（去甲肾上腺素能）轴突的大的致密核心囊泡。 它们的生物活性片段作用于激素或神经递质释放以及靶细胞的几个位点：CgA片段catestatin抑制儿茶酚胺释放，CgA片段vasostatin扩张阻力血管，CgA片段pancreastatin拮抗胰岛素分泌并升高血糖。 该建议开发了3个目标，采用新的靶向发光蛋白构建体（荧光素酶或绿色荧光蛋白[GFP]）或新表达的cDNA，以阐明交感神经流出如何改变儿茶酚胺储存囊泡的组成。 在目标1中，我们采用携带CgA或SgII启动子/荧光素酶报告基因的新型转基因小鼠品系来探索体内交感肾上腺系统中刺激/转录（刺激/分泌/合成）偶联的机制。 在目标2中，我们使用了一系列新的，有针对性的CgA结构域/绿色荧光蛋白（CgA/EGFP）嵌合体，发现信息的一级结构内的儿茶酚胺存储囊泡蛋白，占其贩运到受管制的分泌途径。 在目的3中，我们使用一种新的cDNA表达克隆方法来识别蛋白质的反式，在分泌器内，与CgA相互作用，从而使其贩运到受调节的分泌途径。 这些研究将加深我们对交感神经刺激过程中儿茶酚胺储存囊泡的生物合成及其分泌蛋白的补充的理解。 最后，这些发光蛋白和cDNA试剂可以广泛用于其他研究人员在阐明交感嗜铬系统中的生物合成，贩运和离子通量事件。

DESCRIPTION (provided by applicant): In hypertension, efferent sympathetic activity to post-ganglionic sympathetic nerves and chromaffin cells is increased, contributing to vasoconstriction, sodium retention, and elevations in blood pressure. The chromogranins/secretogranins (chromogranin A [Cga]. Chromogranin B [Cgb]. And secretogranin II [SgII], are a family of acidic proteins found in cores of amine and peptide hormone and neurotransmitter secretory vesicles, such as chromaffin granules and large dense core vesicles of post-ganglionic sympathetic (noradrenergic) axons. Their biologically active fragments act on hormone or neurotransmitter release as well as on target cells at several sites: CgA fragment catestatin inhibits catecholamine release, CgA fragment vasostatin dilates resistance vessels, CgA fragment pancreastatin antagonizes insulin secretion and elevates blood glucose. This proposal develops 3 aims, employing novel targeted photoprotein constructs (luciferase or green fluorescent protein [GFP]) or novel expressed cDNAs, to elucidate how sympathetic outflow changes the composition of catecholamine storage vesicles. In Aim 1, we employ novel transgenic mouse strains, harboring CgA or SgII promoter/luciferase reporters, to probe mechanisms of stimulus/transcription (stimulus/secretion/synthesis) coupling in the sympathoadrenal system in vivo. In Aim 2, we use a series of novel, targeted CgA domain/green fluorescent protein (CgA/EGFP) chimeras to discover information within the primary structure of catecholamine storage vesicle proteins that accounts for their trafficking into the regulated secretory pathway. In Aim 3, we use a novel cDNA expression cloning approach to identify proteins in trans, within the secretory apparatus, which interact with CgA and thereby underlie its trafficking into the regulated secretory pathway. These studies will enhance our understanding of the biosynthesis of catecholamine storage vesicles and the replenishment of their secretory proteins during sympathetic stimulation. Finally, these photoprotein and cDNA reagents can be widely employed by other investigators in elucidating biosynthetic, trafficking, and ion flux events in the sympathochromaffin system.