ROLE OF HYPERABSORTION OF NA IN AIRWAY DISEASE IN VIVO

NA 过度吸收在体内气道疾病中的作用

• 批准号: 7510927
• 负责人: BARBARA R GRUBB
• 金额: $ 27.17万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7510927
• 关键词: Adult; Amiloride; Animal Model; Animals; Aprotinin; Bacteria; Bacterial Infections; Basic Science; Breeding; Cells; Cilia; Clara cell; Coughing; Cystic Fibrosis Transmembrane Conductance Regulator; Data; Deposition; Disease; Environment; Evaluation; Exhibits; Fostering; Genetic; Height; Histologic; Impairment; In Situ Hybridization; In Vitro; Individual; Infection; Inflammation; Knockout Mice; Liquid substance; Litter Size; Lubricants; Lung; Measures; Modeling; Mucociliary Clearance; Mucolytics; Mucous body substance; Mus; Neonatal; Phenotype; Predisposition; Pseudomonas aeruginosa; Pulmonary function tests; Rate; Role; Solid; Surface; Testing; Therapeutic; Therapeutic Agents; Time; Tracheal Epithelium; Transgenic Mice; Translations; Viscosity; Water; Weight Gain; absorption; airway epithelium; airway surface liquid; benzamil; cell type; clinical application; cystic fibrosis airway epithelia; day; disease phenotype; epithelial Na+ channel; in vivo; inhibitor/antagonist; insight; mortality; mouse model; pathogen; promoter; pup; research study; response

The airway surfaces are covered by a thin layer of liquid (ASL) consisting of a mucus layer residing on top of the periciliary liquid layer (PCL). The mucus layer traps debris and pathogens deposited on the airway surfaces, while the PCL layer provides a low viscosity liquid for efficient ciliary beating and functions as a lubricant layer. CF airway epithelia exhibit dysregulated epithelial Na+ channel (ENaC) function and absent CFTR CI- channel function, which results in hyperabsorption of Na+ and osmotically induced water absorption. We hypothesize that the net effect of Na+ hyperabsorption is to (1) deplete the PCL volume, (2) collapse the mucus layer onto the cilia, (3) slow both cilial and cough-dependent mucus clearance, (4) leading to accumulation of mucus plaques and plugs that are a nidus for bacterial colonization. While this hypothesis has been supported by data from in vitro experiments, the lack of an animal model has limited experiments to test this hypothesis in vivo. To test the hypothesis in vivo, we have generated transgenic (TG) mice that use the CCSP promoter to over-express the individual ENaC subunits (a,b,g). Preliminary data indicate that over-expression of the b subunit leads to an elevated rate of airway Na+ absorption, a decrease in PCL volume, marked mucus accumulation and plugging of the airways, and approximately 50% pup mortality by day 28. We propose four Specific Aims to study mice over-expressing b ENac as well as other ENaC subunit combinations.: Aim 1. Mice will be characterized with respect to survival, weight gain, pulmonary function tests, and histological/bioelectrical study of airways. Aim 2. The volume of the PCL/ASL, rate of volume flow, PCL ionic composition, mucus % solids and mucociliary clearance will be measured. Aim 3. We propose bacterial infection studies (P. aeruginosa) on the b TG mice, to generate insights into the initiation of inflammation and infection as well as information on the genetic and morphological changes in the bacteria in response to the host. Aim 4. We will test therapeutic agents aimed at blocking ENaC and dissolving mucus in airways of neonatal and adult b TG mice. Thus, our mouse model will be key in fostering translation of basic science to clinical application in a disease for which we now, for the first time, have an animal airway model.

气道表面被薄层液体（ASL）覆盖，该液体（ASL）由位于周围液体层（PCL）顶部的粘液层组成。粘液层捕获了沉积在气道表面上的碎屑和病原体，而PCL层则提供低粘度液体，可为有效的睫状跳动，并用作润滑剂层。 CF气道上皮表现出失调的上皮Na+通道（ENAC）功能和不具有CFTR CINCH通道功能，从而导致Na+的高吸收和渗透诱导的吸收吸收。我们假设Na+超吸附的净效应是（1）耗尽PCL体积， （2）将粘液层塌陷到纤毛上，（3）缓慢的纤毛和咳嗽依赖性粘液清除率，（4）导致粘液斑块和塞子的积累，这是细菌定殖的Nidus。尽管该假设得到了体外实验的数据支持，但缺乏动物模型的实验有限，可以在体内检验该假设。为了检验体内假设，我们生成了使用CCSP启动子过表达单个ENAC亚基的转基因（TG）小鼠（a，b，g）。初步数据表明，B亚基的过表达导致气道Na+吸收率升高，PCL体积减少，粘液堆积和气道的堵塞率升高，大约50％的PUP死亡率 到第28天，我们提出了四个特定的目的，以研究过表达B ENAC以及其他ENAC亚基组合的小鼠。：AIM 1。将针对气道生存，体重增加，肺功能测试以及气道的组织学/生物电性研究来表征小鼠。 AIM 2。将测量PCL/ASL的体积，体积流量，PCL离子组成，粘液％固体和粘膜纤毛间隙的速率。 AIM 3。我们在B TG小鼠上提出了细菌感染研究（铜绿假单胞菌），以产生对炎症和感染开始的见解，以及有关宿主响应细菌遗传和形态变化的信息。 AIM 4。我们将测试旨在阻止ENAC并溶解粘液在新生儿和成年B TG小鼠气道中的治疗剂。因此，我们的小鼠模型将是将基础科学转化为临床应用中的疾病中的关键，而我们现在首次拥有动物气道模型。