MUCIN AND NON-MUCIN PROTEINS IN GALLSTONE PATHOGENESIS

本项目的总体目标是了解胆囊的作用 粘蛋白在胆固醇结石发病机制中的作用内科或外科 有症状的胆结石的治疗是导致胆结石的常见原因 在美国的住院治疗和消费超过80亿美元 每年的医疗保健费用。胆囊粘蛋白已被证明 在胆结石发病机制中起着重要作用。粘蛋白高分泌 在实验动物和人中均发生在结石形成之前。 粘蛋白还促进胆固醇晶体成核，这是关键的早期步骤 以及粘蛋白凝胶衬里。胆囊提供了 一个理想的环境，胆固醇晶体生长成成熟的 石头人类胆囊表达五种不同粘蛋白的基因， 其中两个，MUC5B和MUC3已被确定为主要的人类 胆囊粘蛋白我们对它的结构特征一无所知， 这些蛋白质与胆汁脂质相互作用， 成岩状态 在这个项目中，一种新的重组方法将被用于鉴定 结合胆汁脂质的MUC5B和MUC3的结构域。的 这项建议的具体目标是：（l）确定主要的人的特征， 胆囊粘蛋白MUC5B和MUC3通过测定核苷酸和 推导的低糖基化氨基和 羧基末端区域，（2）决定基因组组织 这些粘蛋白和（3）鉴定MUC5B和MUC3中的功能结构域。 在具体目标1和2中获得的信息将用于设计 含有单个粘蛋白结构域的构建体。重组粘蛋白 多肽将在细菌中表达并检测脂质结合， 胆固醇晶体成核和囊泡融合测定。的结果 这些研究将提供关于 胆囊粘蛋白的结构与功能 在正常和病理胆囊中。这些信息是必要的， 合理设计预防和治疗 胆结石病

The overall goal of this project is to understand the role of gallbladder mucin in the pathogenesis of cholesterol gallstones. Medical or surgical treatment for symptomatic gallstones is a frequent cause for hospitalization in the United States and consumes more than 8 billion dollars in health care costs per year. Gallbladder mucin has been shown to have a central role in gallstone pathogenesis. Mucin hypersecretion occurs prior to stone formation in both experimental animals and man. Mucin also promotes cholesterol crystal nucleation, a critical early step in stone formation, and the mucin gel lining. The gallbladder provides an ideal environment for growth of cholesterol crystals into mature stones. Human gallbladder expresses genes for five different mucins and two of these, MUC5B and MUC3 have been identified as the major human gallbladder mucins. Nothing is known about the structural features of these proteins which interact with biliary lipids and lead to the lithogenic state. In this project, a novel recombinant approach will be used to identify the structural domains of MUC5B and MUC3 which bind biliary lipids. The specific aims of this proposal are to: (l) characterize the major human gallbladder mucins MUC5B and MUC3 by determining the nucleotide and deduced amino acid sequences of the poorly glycosylated amino- and carboxyl-terminal regions, (2) determine the genomic organization of these mucins and (3) to identify functional domains in MUC5B and MUC3. Information obtained in specific aims 1 and 2 will be used to design constructs containing individual mucin domains. Recombinant mucin polypeptides will be expressed in bacteria and examined in lipid binding, cholesterol crystal nucleation and vesicle fusion assays. The results of these studies will provide new information about the relationship between the structure of the major human gallbladder mucins and their function in normal and pathologic gallbladder. This information is necessary for the rational design of therapies for the prevention and treatment of gallstone disease.