PATHOGENEISIS OF CYSTIC FIBROSIS IN THE GI SYSTEM

胃肠道系统囊性纤维化的发病机制

• 批准号: 6032914
• 负责人: ROBERT C DE LISLE
• 金额: $ 20.22万
• 依托单位: UNIVERSITY OF KANSAS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-03-01 至 2004-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6032914
• 关键词: acidity /alkalinity; acinar cell; binding proteins; carbohydrate structure; chemical cleavage; chloride channels; cystic fibrosis; gastrins; gastrointestinal epithelium; gastrointestinal system; gene expression; gene targeting; genetically modified animals; glycolipids; glycoproteins; immunoprecipitation; intestine obstruction; laboratory mouse; mucins; pathologic process; posttranslational modifications; secretory protein; sulfated glycoprotein 2; tissue /cell culture; zymogens

The long-term objective is to understand how loss of functional CFTR (the cystic fibrosis transmembrane regulator) affects expression and post- translational processing of sulfated glycoconjugates and the role of these altered glycoproteins in the development of cystic fibrosis (CF). High levels of sulfated glycoconjugates with abnormal post-translational processing are believed to contribute to obstruction in the pancreas and intestines, and digestion and absorption of nutrients is abnormal in CF. The model mucin-like sulfated glycoprotein Muclin will be used to explore these issues. Muclin is over-expressed in the pancreas and small intestine of CFTR (-/-) mice, and immunolocalization of Muclin in these tissues shows that it is associated with protein plugs in the acinar lumen and mucin plugs in the intestinal crypt lumen. The hypothesis is that in the absence of functional CFTR, mucin-like glycoconjugates, such as Muclin, are over-expressed and have altered post-translational processing. They then contribute to the deleterious accumulation of protein aggregates in the lumina of the pancreatic acini and small intestinal crypts. The following specific aims will be addressed. 1. To test the hypothesis that post-translational processing of Muclin is altered in the absence of CFTR in epithelial cells which normally express CFTR, i.e., the intestinal crypt cell, and to determine the mechanism of this change. The carbohydrate structure and protein core size of Muclin in normal and CF intestine will be determined. 2. To test the hypothesis that excess Muclin alters the protein secretory pathway in gastrointestinal tissues of CF mice. Pancreatic secretions will be studied in vivo and in vitro in normal and CF mice, and the effect of pH on the interaction of Muclin with zymogens will be assessed. Also, the luminal pH of secretory compartments in CF and normal cells will be measured to test whether CFTR has a functional role in pH gradients in the cell. 3. To test the hypothesis that abnormal acidity in the intestine mediates CF pathogenesis and the over-expression of Muclin. Pathology and Muclin expression will be compared in CF mice, and CF mice crossed with gastrin deficient mice (lack gastric acid secretion) to normalize intestinal Ph.

长期目标是了解功能CFTR的丧失（囊性纤维化跨膜调节剂）如何影响硫酸化糖缀合物的表达和转化后处理，以及这些改变的糖蛋白在囊性纤维化（CF）发展中的作用。据信，具有异常翻译后加工的硫酸化糖缀合物高度有助于胰腺和肠道的阻塞，而养分的消化和吸收在CF中是异常的。模型粘蛋白样硫酸化糖蛋白粘液蛋白将用于探索这些问题。 Muclin在CFTR（ - / - ）小鼠的胰腺和小肠中过表达，在这些组织中，Muclin的免疫定位表明，它与肠道内腔中的蛋白质塞和肠道隐窝中的粘蛋白塞的蛋白塞有关。假设是，在没有功能性CFTR的情况下，粘蛋白样糖缀合物（如粘液）被过表达，并且已经改变了翻译后加工。然后，它们有助于蛋白质聚集体在胰腺acini和小肠道隐窝中的有害积累。将解决以下特定目标。 1。为了测试以下假设：在通常表达CFTR的上皮细胞中，Muclin的翻译后处理发生了改变，即通常表达CFTR，即肠道隐窝细胞，并确定这种变化的机制。将确定正常和CF肠中Muclin的碳水化合物结构和蛋白质核心大小。 2。检验以下假设：多余的muclin会改变CF小鼠胃肠道组织中的蛋白质分泌途径。将在正常和CF小鼠的体内和体外研究胰腺分泌物，并评估pH值对Muclin与Zymogens相互作用的影响。同样，将测量CF和正常细胞中分泌室的腔pH，以测试CFTR在细胞中的pH梯度中是否具有功能作用。 3。检验以下假设：肠道中的异常酸度介导了CF发病机理和Muclin的过表达。在CF小鼠中，将比较病理和粘液木表达，而CF小鼠与胃蛋白缺乏小鼠（缺乏胃酸分泌）交叉以使肠道pH归一化。