ANALYSIS OF THE E COLI STB HEAT STABLE ENTEROTOXIN

大肠杆菌STB热稳定肠毒素的分析

• 批准号: 3147852
• 负责人: LAWRENCE A DREYFUS
• 金额: $ 15.35万
• 依托单位: UNIVERSITY OF MISSOURI KANSAS CITY
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-01 至 1996-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3147852
• 关键词: Escherichia coli; biological signal transduction; eicosanoid metabolism; enterotoxins; epitope mapping; gastrointestinal epithelium; ion transport; laboratory mouse; laboratory rat; monoclonal antibody; phospholipase C; protein kinase C; protein structure function; receptor; receptor binding; secretion; site directed mutagenesis; synthetic peptide; tissue /cell culture

Diarrheal disease is a serious medical and agricultural problem of global significance. Strains of enterotoxigenic Escherichia coli which cause secretory diarrheal disease do so by the elaboration of protein toxins which disturb the normal function of the gut epithelium. One class of E. coli enterotoxins, the heat-stable enterotoxins (STa and STb) are peptides which, although share heat-stability and their genetic location on composite bacterial transposons, bear no functional or structural similarity to one another. The mechanism for STa-mediated secretion is partially understood in that, toxin-induced activation of the brush-border membrane guanylate cyclase is followed by a rapid increase in the mucosal cGMP content which is coupled to net chloride secretion probably through the intestinal epithelial cell cGMP dependent protein kinase. In contrast to our understanding of the mechanism of STa action, little is known of the mechanism by which STb induces intestinal secretion. Preliminary findings suggest that STb induces electrogenic ion transport independent of cAMP or cGMP elevation. In this application, we propose to: 1) investigate the nature and distribution of STb receptors by standard ligand-receptor interaction studies; 2) char- acterize the second messenger response to STb and determine the signal which yields electrogenic ion transport in the gut epithelium. In this part of the study we will investigate the potential role of calcium-dependent ion transport mechanisms including the inter-relationship between phospholipase C, activation and hydrolysis of phosphoinositides, the potential role of protein kinase C, or the involvement of eicosanoid metabolism in response to toxin action. Finally, we will analyze the structural features of STb which contribute receptor binding and biological action. We will accomplish this by a combination of oligonucleotide-directed mutagenesis and epitope mapping of STb. The completion of these aims will add to our understanding of secretory diarrheal disease mechanisms and provide potential rational approaches for disease intervention.

腹泻病是全球严重的医学和农业问题 意义。 产肠毒素大肠杆菌菌株可引起 分泌性腹泻病是通过蛋白质毒素的产生来实现的 扰乱肠道上皮的正常功能。 E类的一类。 大肠杆菌肠毒素，热稳定性肠毒素（STa 和 STb） 尽管具有热稳定性和遗传位置的肽 在复合细菌转座子上，不具有功能或结构 彼此相似。 STa 介导的分泌机制是 部分理解为，毒素诱导的激活 刷状缘膜鸟苷酸环化酶随后迅速增加 粘膜 cGMP 含量与净氯分泌相关 可能通过肠上皮细胞cGMP依赖性蛋白 激酶。 与我们对 STa 作用机制的理解相反， 对于 STb 诱导肠炎的机制知之甚少。 分泌。 初步研究结果表明 STb 会诱导生电 离子传输与 cAMP 或 cGMP 升高无关。 在这个 应用中，我们建议：1）调查的性质和分布 STb 受体通过标准配体-受体相互作用研究； 2) 字符- 表征对 STb 的第二信使响应并确定信号 其在肠道上皮中产生电离子传输。 在这个 作为研究的一部分，我们将调查潜在的作用 钙依赖性离子转运机制包括 磷脂酶C、活化和水解之间的相互关系 磷酸肌醇、蛋白激酶 C 的潜在作用或 参与类二十烷酸代谢响应毒素作用。 最后，我们将分析 STb 的结构特征，这些特征有助于 受体结合和生物作用。 我们将通过以下方式实现这一目标 寡核苷酸定向诱变和表位作图的结合 STb。 这些目标的完成将加深我们对 分泌性腹泻疾病机制并提供潜在的合理性 疾病干预的方法。