Altered Proteolytic Processing of ENaC in the Pathogenesis of Cystic Fibrosis

ENaC 蛋白水解过程在囊性纤维化发病机制中的改变

• 批准号: 7546549
• 负责人: MICHAEL M MYERBURG
• 金额: $ 12.49万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7546549
• 关键词: Anabolism; Apical; Arts; Biochemical; Biochemistry; Breathing; Bypass; Caucasians; Caucasoid Race; Cell surface; Cells; Cessation of life; Chronic; Cilia; Cleaved cell; Cystic Fibrosis; Data; Defense Mechanisms; Development; Disease; Electrophysiology (science); Epithelial; Epithelial Cells; Equilibrium; Goals; Human; In Vitro; Individual; Infection; Ion Transport; Laboratories; Liquid substance; Lung; Lung Transplantation; Maintenance; Methods; Modeling; Movement; Mucous body substance; Nature; Particulate Matter; Pathogenesis; Pathway interactions; Pb clearance; Peptide Hydrolases; Physicians; Physiological; Physiology; Process; Protease Inhibitor; Proteolysis; Proteolytic Processing; Regulation; Regulation of Proteolysis; Research Personnel; Respiratory Failure; Role; Sodium; Sodium Channel; Sodium Chloride; Surface; System; Testing; Viscosity; Water; Work; absorption; abstracting; airway epithelium; airway obstruction; airway surface liquid; apical membrane; cystic fibrosis airway; cystic fibrosis airway epithelia; cystic fibrosis patients; driving force; epithelial Na+ channel; epithelial amiloride-sensitive sodium channel; human PRSS8 protein; improved; nexin; novel; pathogen; premature; prevent; skills; trans-Golgi Network

DESCRIPTION (provided by applicant): Cystic fibrosis (CF) is the most common severe autosomal recessive disease in Caucasian individuals. CF is characterized by an imbalance in the movement of salt and water across the airway surface, such that the overlying mucus layer becomes dehydrated, collapses onto the airway wall, and fails to be cleared from the airways. This impaired mucus clearance leads to chronic infection and airways obstruction, and ultimately causes respiratory failure leading to premature death or lung transplantation. Sodium absorption through the epithelial sodium channel (ENaC), which establishes an osmotic driving force for the absorption of airway surface liquid (ASL), is abnormally high in CF patients for unknown reasons. Furthermore, when the activity of ENaC is inhibited in CF, the ASL becomes hydrated and mucus clearance improves. Our preliminary work suggests that imbalances between proteases, which activate the channel, and endogenous protease inhibitors on the luminal airway surface causes sodium hyperabsorption in CF airways. The goal of this K08 application is to provide the PI with essential skills to develop into a successful academic physician and achieve independent scientific investigator status with a focus on airway physiology as it relates to CF. The PI will focus upon the regulation of airway surface liquid volume by ENaC in normal and CF airway epithelium. The primary scientific aims of this proposal are to (i) define the role of the protease/protease inhibitor balance in the physiological regulation of ENaC and ASL depth, (ii) determine which channel activating proteases and protease inhibitors are involved in the regulation of ENaC in the airway, and (iii) define the mechanism by which proteolytic processing of ENaC is altered in CF. To achieve his goal and complete these aims the PI will combine focused graduate course work with state-of-the-art laboratory methods to delineate the electrophysiology and biochemistry of ENaC in primary human airway epithelial cells and relevant heterologous expression systems. Understanding the nature of proteolytic regulation of ENaC activity in normal and diseased airways will ultimately direct the development of novel therapies to mitigate sodium hyperabsorption and thereby restore normal ASL volume and mucus clearance in CF airways. (End of Abstract)

描述（由申请人提供）： 囊性纤维化（CF）是白种人中最常见的严重常染色体隐性遗传疾病。 CF 的特点是盐和水在气道表面的运动不平衡，导致上面的粘液层脱水，塌陷到气道壁上，并且无法从气道中清除。这种粘液清除受损会导致慢性感染和气道阻塞，并最终导致呼吸衰竭，导致过早死亡或肺移植。 CF 患者通过上皮钠通道 (ENaC) 的钠吸收异常高，该通道为气道表面液体 (ASL) 的吸收建立了渗透驱动力，原因不明。此外，当 CF 中 ENaC 的活性受到抑制时，ASL 会变得水合，粘液清除能力也会改善。我们的初步工作表明，激活通道的蛋白酶与管腔气道表面的内源性蛋白酶抑制剂之间的不平衡会导致 CF 气道中钠的过度吸收。该 K08 应用程序的目标是为 PI 提供发展成为一名成功的学术医生的基本技能，并获得独立的科学研究者身份，重点关注与 CF 相关的气道生理学。 PI 将重点关注 ENaC 在正常和 CF 气道上皮中对气道表面液体体积的调节。该提案的主要科学目的是（i）确定蛋白酶/蛋白酶抑制剂平衡在 ENaC 和 ASL 深度生理调节中的作用，（ii）确定哪些通道激活蛋白酶和蛋白酶抑制剂参与气道中 ENaC 的调节，以及（iii）确定 CF 中 ENaC 蛋白水解过程改变的机制。为了实现他的目标并完成这些目标，PI 将把重点研究生课程工作与最先进的实验室方法相结合，以描述原代人气道上皮细胞和相关异源表达系统中 ENaC 的电生理学和生物化学。了解正常和患病气道中 ENaC 活性的蛋白水解调节本质将最终指导新疗法的开发，以减轻钠吸收过度，从而恢复 CF 气道中的正常 ASL 体积和粘液清除能力。 （摘要完）