[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: 6754523
• 负责人: David I Yule
• 金额: $ 34.43万
• 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/6754523
• 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）：唾液的正常产生对口腔健康很重要。了解控制唾液腺液体和蛋白质分泌的特定机制对于制定唾液腺功能障碍的策略至关重要。唾液的流体成分的产生主要由胞质钙（[Ca2+] i）的增加来控制，这是通过空间分离的离子电导值的激活而控制的。尽管蛋白质的胞吐作用是通过CA2+和CAMP介导的效应子进行的，但要测试的中心假设是流体和蛋白质分泌的动力学都由[Ca2+] I信号在小鼠parotid腺泡细胞中引起的[CA2+] I信号的独特特征所控制。将在Ca2+刺激的胞吐作用的背景下研究负责腮腺腺泡细胞中蛋白质分泌的机制，并旨在旨在阐明负责启动的机制，快速发展至全局Ca2+ I信号，并随后对信号的有效终止。使用指示剂染料的数字成像以及肌醇1,4,5-三磷酸（INSP3）和ryanodine受体（RYR）激动剂的闪光光解有关INSP 3受体的相对贡献，而RYR对Ca2+信号的启动的相对贡献将得到确定。通过施加高细胞内Ca2 +缓冲，通过对笼子分子的局部光解，将定义腮腺细胞中不变的全局Ca +信号的机制。不同CA载荷在CA2+信号终止的Ca2+清除机制的相对贡献将由选择性药理干预确定。时间分辨的膜电容测量和光学方法将用于监测单细胞的胞吐作用。使用此技术，将定义胞吐作用的Ca2+灵敏度。此外，通过探测负责CAMC和CA2+刺激胞胞菌之间表现出的协同作用的机制，CAMP和Ca2+在颗粒募集和融合过程中的相对作用将建立。可以预见的是，在呈滴虫和蛋白质分泌的腮腺特异性机制中获得的知识对于阐明新的唾液腺功能障碍的新疗法很重要。