权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

BILIARY SECRETORY PATHWAYS IN CYSTIC FIBROSIS

囊性纤维化中的胆道分泌途径

基本信息

批准号：
6626908
负责人：
WON KYOO CHO
金额：
$ 9.3万
依托单位：
INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
依托单位国家：
美国
项目类别：
财政年份：
1999
资助国家：
美国
起止时间：
1999-05-01 至 2004-12-31
项目状态：
已结题

项目摘要

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 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 secreting 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. A novel polarized isolated bile duct unit (IBDU) prepared from rat liver has demonstrated to be an ideal tool to study bile ductular secretion but the lack of CF rat model limited its use in CF studies. By applying these isolation methods, recently, IBDUs have been isolated from normal and CF mice. Therefore, the aims of this research are to further characterize bile duct cells (BDC) and IBDU from normal and CF knockout mice, to characterize ion transporters in BDC, 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. Preliminary experiments 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. Quantitative videomicroscopy will be used to screen potential secretagogues to stimulate biliary secretion in normal and CF mice and to characterize their underlying ion transporters by using ion substitutions and inhibitor studies. These ion transporters will be further studied by BCECF dual ratio methods for measuring pH, micropuncture, and patch clamping techniques. Signal transduction systems involved in their action will be studied by monitoring changes in the concentrations of secondary messengers. Understanding transport systems and their underlying mechanisms of biliary secretion 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, as well as help to successfully compete for future research grants.

囊性纤维化（CF）是白人中最常见的致命遗传性疾病。随着CF患者寿命的延长，肝病已成为第二大死因。 CF疾病的发生被认为是由于胆管的分泌缺陷导致顽强的胆汁分泌物阻塞胆管，从而导致局灶性汇管周围胆汁纤维化/肝硬化。这一解释加上最近发现 CFTR 仅在胆管细胞上表达，而不在肝细胞上表达，表明研究胆汁分泌对于了解 CF 肝脏的病理生理学和制定治疗策略至关重要。由大鼠肝脏制备的新型极化分离胆管单元 (IBDU) 已被证明是研究胆管分泌的理想工具，但缺乏 CF 大鼠模型限制了其在 CF 研究中的使用。通过应用这些分离方法，最近已从正常小鼠和 CF 小鼠中分离出 IBDU。因此，本研究的目的是进一步表征正常和CF敲除小鼠的胆管细胞（BDC）和IBDU，表征BDC中的离子转运蛋白，并研究包括神经内分泌肽在内的各种促分泌剂在胆汁分泌中的作用和机制，以找到激活CF小鼠中替代的、不依赖于cAMP的胆汁分泌途径的方法。从正常小鼠中分离 IBDU 的初步实验产生了完整的极化功能性 IBDU，其对促胰液素、血管活性肠肽和 DBcAMP-IBMX 做出反应。类似的 IBDU 也从 CF 小鼠中分离出来，但需要进一步表征。定量视频显微镜将用于筛选潜在的促分泌剂，以刺激正常和 CF 小鼠的胆汁分泌，并通过离子替代和抑制剂研究来表征其潜在的离子转运蛋白。这些离子转运蛋白将通过用于测量 pH 值的 BCECF 双比率方法、微穿刺和膜片钳技术进行进一步研究。将通过监测第二信使浓度的变化来研究参与其作用的信号转导系统。了解正常小鼠和 CF 小鼠的转运系统及其胆汁分泌的基本机制将有助于制定克服 CFTR 缺陷的治疗方法。反过来，该项目将为候选人提供一个绝佳的机会来扩大和发展研究和认知技能，成为独立研究员，并帮助成功竞争未来的研究资助。