Volume Regulatory Pathways in Cystic Fibrosis Mice

囊性纤维化小鼠的容量调节途径

• 批准号: 6623078
• 负责人: WON KYOO CHO
• 金额: $ 6.3万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-01-01 至 2003-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6623078
• 关键词: cell morphology; chloride channels; cystic fibrosis; disease /disorder model; drug screening /evaluation; gallbladder; gallbladder disorder; gastrointestinal agents; genetically modified animals; ion transport; laboratory mouse; liver disorder; osmotic pressure; potassium channel; secretion; video microscopy; voltage /patch clamp

DESCRIPTION (provided by applicant): Cystic fibrosis (CF) is the most common lethal inherited diseases in white population. As CF patients live longer, liver disease has become the second leading cause of death. The development of CF liver disease is believed to result from the secretory defects in the bile ducts leading to the obstructions of bile ductules by tenacious bile secretions, thereby resulting in focal periportal biliary fibrosis/cirrhosis. This explanation in addition to the recent finding that CFTR is only expressed on bile duct cells, but not on hepatocytes, suggest that studying biliary secretion is crucial to understanding the pathophysiology and developing therapeutic strategies for CF liver. By applying the isolation methods developed from rat, recently, novel polarized isolated bile duct unit (IBDU)s have been isolated from normal and CF mice. Therefore, the aims of this research are to further characterize cholangiocytes and IBDU from normal and CF knockout mice, to characterize ion transporters in these cells, and to study the actions and mechanisms of various secretagogues including neuroendocrine peptides in biliary secretion in order to find ways to activate alternative, camp-independent biliary secretory pathways in CF mice. Recent success to isolate IBDU from normal mouse yielded intact polarized functional IBDU that responds to secretin, vasoactive intestinal peptide, and DBcAMP/IBMX. Similar IBDUs were also isolated from CF mice but need further characterization. Recent experiments to study the volume-activated chloride channel as a possible alternative biliary secretory pathway in CF cholangiocytes indicate that cell volume regulation, assessed by regulatory volume decrease (RVD) after hypotonic challenge, is impaired in CF cholangiocytes. Since cell volume regulation is thought to be vital for many cell functions including secretion and ion/substrate transport, this R03 grant is proposing to examine underlying ion transport mechanisms mediating cell volume regulation and their alterations, and to find agent(s) which can correct the impaired cell volume regulation in CF cholangiocytes. Quantitative videomicroscopy will be used to examine the effect of specific inhibitors to ion channels and transporters involved in RVD, and to screen potential agents to correct the impaired RVD of CF mouse cholangiocytes. These promising inhibitors and stimulating agents to ion channels and transporters thus identified will be further investigated by isotope efflux study to examine their effect on Cl-and K+ ion transport, and patch clamping techniques to characterize the ion channels and transporters involved in the RVD. Understanding transport systems and their underlying mechanisms of biliary secretion and cell volume regulation in normal and CF mice will help to formulate therapeutic approaches to overcome the CFTR defect. This project, in turn, will provide the candidate with an excellent opportunity to broaden and develop research and cognitive skills to become independent researcher, the necessary research resources to carry out the proposed research projects, as well as help successfully compete for future research grants.

描述（由申请人提供）： 囊性纤维化（CF）是白色最常见的致死性遗传疾病 人口。随着CF患者的寿命更长，肝病已成为第二种 死亡的主要原因。 CF肝病的发展被认为是 胆管中的分泌缺陷导致障碍物 通过顽强的胆汁分泌物的胆管导管，从而导致焦点 周围胆道纤维化/肝硬化。除了 最近发现CFTR仅在胆管细胞上表达，但不在 肝细胞，表明研究胆道分泌对于 了解CF的病理生理学和制定治疗策略 肝。通过应用从大鼠开发的隔离方法，最近是新颖的 偏振分离的胆管单位（IBDU）已从正常和CF中分离出来 老鼠。因此，这项研究的目的是进一步表征 来自正常和CF敲除小鼠的胆管细胞和IBDU，以表征离子 这些细胞中的转运蛋白，并研究各种的作用和机制 包括神经内分泌肽在胆道分泌中的促促虫 寻找激活替代性的，独立的胆道分泌物的方法 CF小鼠的途径。最近成功地将IBDU与正常小鼠分离出来的成功 完整的两极化功能IBDU，对Systim，血管活性做出反应 肠肽和DBCAMP/IBMX。也从CF中分离出类似的IBDU 小鼠，但需要进一步的表征。最近研究的实验 体积激活的氯化物通道作为可能的替代胆道分泌 CF胆管细胞中的途径表明，在低音挑战后通过调节体积减少（RVD）评估的细胞体积调节受到CF的损害 胆管细胞。由于细胞体积调节被认为对许多人至关重要 细胞功能包括分泌和离子/底物传输，此R03授予 正在提议检查介导细胞的基本离子传输机制 音量调节及其更改，并找到可以纠正的代理 CF胆管细胞中细胞体积调节受损。定量 视频显微镜将用于检查特定抑制剂对 与RVD有关的离子通道和转运蛋白，并筛选潜在药物 纠正CF小鼠胆管细胞的RVD受损。这些有希望的 因此，抑制剂和刺激剂对离子通道和转运蛋白 同位素外排研究将进一步研究确定的 它们对Cl-and K+离子传输的影响以及贴片夹技术 表征与RVD有关的离子通道和转运蛋白。 了解运输系统及其胆道的基本机制 正常和CF小鼠的分泌和细胞体积调节将有助于 制定治疗方法来克服CFTR缺陷。这个项目，在 转弯，将为候选人提供拓宽和 发展研究和认知技能，成为独立研究人员， 进行拟议的研究项目的必要研究资源， 并帮助成功竞争未来的研究补助金。