CHROMOGRANIN A--NICOTINIC SIGNALING AND DESENSITIZATION

嗜铬粒蛋白 A——烟碱信号传导和脱敏

• 批准号: 2898187
• 负责人: SUSHIL K MAHATA
• 金额: $ 8.47万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-30 至 2002-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2898187
• 关键词: PC12 cells; SDS polyacrylamide gel electrophoresis; biofeedback; biological signal transduction; catecholamines; chromaffin cells; chromogranins; genetic promoter element; genetic transcription; mass spectrometry; neurotransmitter metabolism; nicotine; protein metabolism; secretion; tissue /cell culture

Chromogranin A: nicotinic signaling and desensitization. Nicotine is a component of tobacco that motivates continued abuse despite harmful effects. Catecholamine release from catecholaminergic cells is triggered by nicotinic cholinergic stimulation, prompting exocytotic co-release of storage vesicle constituents: catecholamines, neuropeptides, and acidic chromogranins, the major component being chromogranin A (CgA). CgA is cleaved to biologically active peptides, such as a novel fragment (CgA344-364, which we discovered and named "catestatin") that feedback-inhibits catecholamine release. We found that stimulation of neuronal nicotinic receptors causes secretion of catecholamines and CgA, transcriptionally upregulates the biosynthesis of CgA and catecholamines, and desensitizes (creates tolerance to) further nicotinic responses, both secretory and transcriptional. In preliminary studies, we found that catestatin antagonized all of these cholinergic responses. Thus, CgA (and its fragment catestatin) seem to play a central role in neuronal nicotinic cholinergic signaling, both in responding positively to nicotine (in secretion and transcription), and in blocking all known stimulatory (secretory or transcriptional) or desensitizing action of nicotine. These features of CgA's and catestatin's responses and action suggest a homeostatic, negative feedback role. Here we will explore these functions of CgA and catestatin, using cultured chromaffin cells. Two general areas will be characterized. I. Effects of nicotinic cholinergic stimulation to cause secretion (of catecholamines and CgA), CgA biosynthesis, and desensitization of (tolerance to) further secretion or transcriptional responses to nicotine. We have already characterized CgA promoter domains (in cis) which mediate the response to nicotine, and have begun to establish signal transduction pathways involved in transcription and its desensitization. II. Catestatin's antagonism of nicotinic responses (secretion, transcription, and desensitization thereof). We characterized catestatin's inhibitory effects on secretion, specifically as a non-competitive nicotinic cholinergic antagonist, and established its effect on nicotinic signal transduction, as well as protection against prior nicotinic desensitization. These studies may establish a novel homeostatic (negative feedback) mechanism by which an endogenous peptide antagonizes nicotinic stimulation of catecholamine release, CgA gene transcription, and desensitization of both secretion and transcription. Such protection against desensitization may be advantageous to an organism during circumstances of prolonged stress, perhaps guarding against premature termination of secretory and transcriptional responses to physiological nicotinic stimulation.

染色体蛋白A：烟碱信号传导和脱敏。尼古丁是一个 烟草的组成部分，尽管有害 效果。触发从儿茶酚胺能细胞释放儿茶酚胺 通过烟碱胆碱能刺激，促使胞吐共释放 储存囊泡成分：儿茶酚胺，神经肽和酸性 染色体蛋白，主要成分是铬烷蛋白A（CGA）。 CGA 被裂解至生物活性肽，例如新型碎片 （CGA344-364，我们发现并命名为“ catestatin”） 反馈抑制儿茶酚胺释放。我们发现刺激 神经元烟碱受体会导致儿茶酚胺的分泌和 CGA在转录上上调了CGA和 儿茶酚胺，并进一步脱敏（创造宽容） 分泌和转录的烟碱反应。在初步 研究，我们发现Catestatin拮抗所有这些胆碱能 回答。因此，CGA（及其碎片catestatin）似乎在玩 在神经元烟碱胆碱能信号中的中心作用，都在 对尼古丁（分泌和转录）做出积极反应， 阻止所有已知的刺激性（分泌或转录）或 尼古丁的脱敏作用。 CGA的这些功能 Catestatin的回答和行动表明了体内稳态，负面 反馈角色。在这里，我们将探索CGA和 猫蛋白，使用培养的铬蛋白细胞。两个一般区域将是 特征。 I.烟碱胆碱能刺激的影响 分泌（Catecholamines和CGA），CGA生物合成和 （对）进一步分泌或转录的脱敏 对尼古丁的反应。我们已经描述了CGA启动子 域（顺式），介导对尼古丁的反应，并具有 开始建立涉及的信号转导途径 转录及其脱敏。 ii。 Catestatin的对抗 烟碱反应（分泌，转录和脱敏 它）。我们表征了Catestatin对分泌的抑制作用， 特别是作为非竞争性烟碱胆碱能拮抗剂，并且 建立了其对烟碱信号转导的影响，以及 防止先前的烟碱脱敏。这些研究可能 建立一种新颖的稳态（负反馈）机制 内源性肽会拮抗烟碱刺激 儿茶酚胺释放，CGA基因转录和脱敏 分泌和转录。 这样的保护 脱敏可能对有机体有利 长时间压力的情况，也许会防止 分泌和转录响应的过早终止 生理烟碱刺激。