[Ca2+]i and Secretory Dynamics in Parotid Acinar Cells

[Ca2]i 和腮腺腺泡细胞的分泌动态

• 批准号: 6531423
• 负责人: David I Yule
• 金额: $ 36.07万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-15 至 2007-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6531423
• 关键词: SDS polyacrylamide gel electrophoresis; acinar cell; biological fluid transport; biological signal transduction; biological transport; calcium; calcium flux; confocal scanning microscopy; cyclic AMP; digital imaging; exocytosis; immunocytochemistry; laboratory mouse; parotid gland; protein transport; saliva; salivary disorder; secretion; voltage /patch clamp

DESCRIPTION (provided by applicant): The normal production of saliva is important for oral health. Understanding the specific mechanisms which govern fluid and protein secretion from salivary glands is central to the development of strategies for the treatment of salivary gland dysfunction. The production of the fluid component of saliva is primarily controlled by an increase in cytosolic calcium ([Ca2+]i) through activation of spatially separated ionic conductance values. While the exocytosis of proteins occurs through both Ca2+ and cAMP mediated effectors, the central hypothesis to be tested is that the dynamics of both fluid and protein secretion are controlled by the unique characteristics of the [Ca2+]i signals elicited in mouse parotid acinar cells. The mechanisms responsible for protein secretion in parotid acinar cells will be studied in the context of Ca2+ stimulated exocytosis, and the Specific Aims are designed to elucidate the mechanisms responsible for the initiation, rapid progression to a global Ca2+i signal, and subsequent efficient termination of the signal. Using digital imaging of indicator dyes combined with flash photolysis of inositol 1,4,5-trisphosphate (InsP3) and ryanodine receptor (RyR) agonists the relative contribution of InsP 3 receptors and RyR to the initiation of Ca2+ signals will be determined. By imposing high intracellular Ca2+ buffering and by local photolysis of caged molecules the mechanism underlying the coordinated, invariably global Ca + signal in parotid cells will be defined. The relative contribution of Ca2+ clearance mechanisms at different Ca loads to the termination of Ca2+ signals will be determined by selective pharmacological intervention. Time-resolved membrane capacitance measurements and optical methods will be utilized to monitor exocytosis from single cells. Using this technique the Ca2+ sensitivity of exocytosis will be defined. In addition, by probing the mechanism which is responsible for the synergism exhibited between cAMP and Ca2+ stimulated exocytosis the relative roles of cAMP and Ca2+ in the processes of granule recruitment and fusion will be established. It is envisioned that the knowledge gained into the parotid specific mechanisms responsible for fluid and protein secretion will be important in elucidating new therapy for salivary gland dysfunction.

描述（由申请人提供）：唾液的正常产生对于口腔健康很重要。了解控制唾液腺液体和蛋白质分泌的具体机制对于制定治疗唾液腺功能障碍的策略至关重要。唾液液体成分的产生主要是通过激活空间分离的离子电导值来增加胞质钙 ([Ca2+]i) 来控制的。虽然蛋白质的胞吐作用是通过 Ca2+ 和 cAMP 介导的效应器发生的，但要测试的中心假设是液体和蛋白质分泌的动力学均受小鼠腮腺腺泡细胞中引发的 [Ca2+]i 信号的独特特征控制。将在 Ca2+ 刺激的胞吐作用的背景下研究腮腺腺泡细胞中负责蛋白质分泌的机制，具体目标旨在阐明负责启动、快速进展为全局 Ca2+i 信号以及随后有效终止信号的机制。使用指示剂染料的数字成像结合肌醇 1,4,5-三磷酸 (InsP3) 和兰尼碱受体 (RyR) 激动剂的闪光光解，将确定 InsP 3 受体和 RyR 对 Ca2+ 信号启动的相对贡献。通过施加高细胞内 Ca2+ 缓冲和笼中分子的局部光解，将定义腮腺细胞中协调的、恒定的全局 Ca2+ 信号的机制。不同Ca负荷下Ca2+清除机制对Ca2+信号终止的相对贡献将通过选择性药理干预来确定。时间分辨膜电容测量和光学方法将用于监测单细胞的胞吐作用。使用该技术将定义胞吐作用的 Ca2+ 敏感性。此外，通过探讨 cAMP 和 Ca2+ 刺激的胞吐作用之间表现出的协同作用的机制，将确定 cAMP 和 Ca2+ 在颗粒募集和融合过程中的相对作用。预计，对负责液体和蛋白质分泌的腮腺特异性机制的了解对于阐明唾液腺功能障碍的新疗法将非常重要。