In Vivo Chromaffin Granule depletion and Blood Pressure

体内嗜铬颗粒消耗和血压

• 批准号: 7844958
• 负责人: SUSHIL K MAHATA
• 金额: $ 24.11万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7844958
• 关键词: Acetylcholine; Adenosine Triphosphate; Adrenal Glands; Adrenal Medulla; African; Asians; Autonomic nervous system; Bacterial Artificial Chromosomes; Binding; Binding Sites; Biogenesis; Blood Pressure; Blood Vessels; CHGA gene; Cardiovascular Physiology; Catecholamines; Cations; Cattle; Cells; Chromaffin Cells; Chromaffin granule; Chromogranin A; Chromogranins; Circadian Rhythms; Complex; DNA Resequencing; Development; Diastolic blood pressure; Dimensions; Dopa; Drosophila pros protein; Environment; Ethnic group; European; Exhibits; Figs - dietary; Gene Expression; Genes; Heterozygote; Hormones; Human; Hypertension; Knock-out; Left; Membrane; Methods; Mexican Americans; Mus; Names; Neuroeffector Junction; Neuropeptides; Neurotransmitters; Nicotine; Nicotinic Antagonists; Organism; Peptides; Phenotype; Pheochromocytoma; Physiological; Plasma; Research Design; Research Personnel; Risk; Role; Smooth Muscle; Stress; Transgenes; Transgenic Mice; Transgenic Organisms; Variant; Vasodilator Agents; Ventricular; Vesicle; base; cholinergic; chromogranin A (344-364); coping; in vivo; mRNA Differential Displays; neuropeptide Y; novel; pancreastatin; research study; response; secretory protein; stressor; vasostatin

Chromogranin A (CHGA), a 48 kDa acidic secretory protein, is co-stored with neurotransmitters (catecholamines, ATP, and neuropetide Y [NPY]) in vesicles called chromaffin granules and co-released in response to nicotinic-cholinergic stimulation. CHGA is a proprotein giving rise to biologically active peptides including a catecholamine release inhibitory peptide (bovine CHGA344.364 and human CHGA352.372) that we discovered and named catestatin. Since genetically modified mice are becoming increasingly important in studies designed to understand basic mechanisms of cardiovascular function, we have generated systemic and conditional Chga knockout (Chga-/-) mice. The systemic Chga-/- mice displayed the following phenotypes: (i) Depletion of chromaffin granules accompanied by higher systolic and diastolic blood pressure (BP), (ii) "Non-dipping" BP (no diurnal variation), (iii) Increment of left ventricular dimension, (iv) Decrements of adrenal catecholamine, NPY and ATP levels, (v) Increments of plasma catecholamine and NPY levels, and (vi) Exaggerated BP response to treadmill stress. We have already generated bacterial artificial chromosome (BAG) transgenic mice containing the human CHGA gene (CHGA+/+) into the germline of Chga-/- mice (CHGA+/+;Chga-/-) to "rescue" Chga knockout phenotypes. The present proposal develops 3 specific aims: Aim I. Explore the mechanism of development of high BP (SBP and DBP) and "non-dipping" BP phenotypes in Chga-/- mice, including the role of cotransmitters. Aim II. "Rescue" the BP and "nondipping" BP phenotypes observed in Chga-/- mice by introduction of a BAG containing the human CHGA gene (CHGA+/+) into the germline of Chga-/- mice (CHGA+/+\Chga-/-). Aim III. Establish the role of a naturally occurring human catestatin variant in mice (expressing a BAC-catestatin variant transgene) in counteracting sympathoadrenal stress BP responses. These studies, utilizing unique knockout, transgenic, and human variants of catestatin, are likely to establish the role of CHGA fragment catestatin and catecholamine co-transmitters in the development of complex phenotypes such as hypertension, and the influence of naturally occurring catestatin variants in counteracting BP responses to sympathoadrenal stressors.

嗜铬粒蛋白 A (CHGA) 是一种 48 kDa 的酸性分泌蛋白，与神经递质共同储存 （儿茶酚胺、ATP 和神经肽 Y [NPY]）位于称为嗜铬颗粒的囊泡中，并响应烟碱胆碱能刺激而共同释放。 CHGA 是一种前蛋白，可产生生物活性肽，包括我们发现的儿茶酚胺释放抑制肽（牛 CHGA344.364 和人 CHGA352.372），并将其命名为儿茶素。由于转基因小鼠在旨在了解心血管功能基本机制的研究中变得越来越重要，因此我们培育了系统性和条件性 Chga 基因敲除 (Chga-/-) 小鼠。全身 Chga-/- 小鼠表现出以下表型：(i) 嗜铬颗粒消耗，伴有较高的收缩压和舒张压 (BP)，(ii) “非下降”血压（无昼夜变化），(iii) 左心室尺寸增加，(iv) 肾上腺儿茶酚胺、NPY 和 ATP 水平减少，(v) 肾上腺儿茶酚胺、NPY 和 ATP 水平减少， 血浆儿茶酚胺和 NPY 水平，以及 (vi) 血压对跑步机压力的过度反应。我们已经培育出含有人类 CHGA 基因 (CHGA+/+) 的细菌人工染色体 (BAG) 转基因小鼠，进入 Chga-/- 小鼠 (CHGA+/+;Chga-/-) 种系，以“拯救”Chga 敲除表型。本提案制定了 3 个具体目标： 目标 I. 探索 Chga-/- 小鼠高血压（SBP 和 DBP）和“非下降”血压表型的发展机制，包括共递质的作用。目标二。 “拯救”BP与“不浸” 通过引入含有人类 BAG 的 BAG 在 Chga-/- 小鼠中观察到 BP 表型 CHGA 基因 (CHGA+/+) 进入 Chga-/- 小鼠的种系 (CHGA+/+\Chga-/-)。目标三。建立 小鼠中天然存在的人类连环蛋白变体（表达 BAC-连环蛋白变体转基因）在抵消交感肾上腺应激血压反应中的作用。这些研究利用了儿茶素的独特敲除、转基因和人类变体，很可能确定 CHGA 片段儿茶素和儿茶酚胺共递质在高血压等复杂表型的发展中的作用，以及天然存在的儿茶素变体在抵消血压对交感肾上腺应激源反应中的影响。