KININS AND EPITHELIAL ION TRANSPORT MECHANISMS

激肽和上皮离子转运机制

• 批准号: 3363475
• 负责人: HARRY S MARGOLIUS
• 金额: $ 17.29万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-05-01 至 1995-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3363475
• 关键词: bradykinin; epithelium; hormone regulation /control mechanism; ion transport; kallikreins; kinins; laboratory mouse; potassium; receptor; tissue /cell culture

The work in this proposal will advance the understanding of the kallikrein-kinin system and its role(s) in the regulation of epithelial ion transport, a process important to the maintenance of normal cell function. Cystic fibrosis is now thought to result from an epithelial defect in chloride transport, e.g., and secretory diarrhea from inappropriate regulation of the same process. Ion-transporting phenomena also contribute to aspects of blood pressure control and diabetes, and aberrancies in the kallikrein-kinin system have been associated with both of these diseases. The specific aims of this proposal will establish whether the kallikrein-kinin system participates as an autocrine or paracrine regulator of chloride transport in T84 cells, a human colonic epithelial cell line derived from an adenocarcinoma. The system in these cells will be activated or inhibited, and the effects on chloride movements monitored in the Ussing chamber. This will be accomplished (1) by activating or inhibiting the protease kallikrein with appropriate agents, and establishing the specificity of the results by blocking the actions of the released kinin peptide at its receptors, and (2) by increasing the activity of the system using physiological signals such as growing the cells as a tumor in the nude mouse, or increasing the extracellular potassium concentration, treatments that increase kallikrein production and kinin sensitivity. The molecular mechanisms underlying the physiologically-induced changes in the kallikrein-kinin system will also be investigated. 125I-bradykinin binding studies will measure changes in kinin receptor number and/or affinity, and determinations of calcium mobilization and inositol phosphate synthesis will measure changes in second messenger production. Kallikrein (or kallikrein like) gene expression will be studied by evaluating mRNA transcripts, and the role of the Na+-K+-Cl- cotransport system in the IV effect will be examined by inhibiting the cotransport with bumetanide prior to a potassium challenge. The regulation of ion transport in epithelia is complex, involving multiple neural and hormonal influences. Elucidation of the contribution of the kallikrein-kinin system to these processes will reduce this complexity. These findings will be relevant not only to the definition of fundamental cellular processes, but also to the understanding of human disease.

本提案中的工作将促进对 激肽释放酶-激肽系统及其在上皮细胞调节中的作用 离子转运是维持正常细胞的重要过程 功能 囊性纤维化现在被认为是由于上皮细胞 氯化物运输缺陷，例如，和分泌性腹泻 对同一过程的不恰当管理。 离子输运现象 也有助于血压控制和糖尿病方面， 激肽释放酶-激肽系统的异常与这两种疾病有关 这些疾病。 本提案的具体目标将确定 激肽释放酶-激肽系统以自分泌或旁分泌的方式参与 人结肠上皮细胞T84中氯离子转运的调节因子 来源于腺癌的细胞系。 这些细胞中的系统 被激活或抑制，以及对氯离子运动的影响 在Ussing室中进行监控。 这将通过（1） 用合适的试剂激活或抑制蛋白酶激肽释放酶， 并通过阻止这些行为来确定结果的特异性 释放的激肽肽在其受体，和（2）通过增加 使用生理信号的系统活动，例如生长 细胞作为裸鼠肿瘤，或增加细胞外 钾浓度，增加激肽释放酶产生的治疗 和激肽敏感性。 生理诱导的细胞凋亡的分子机制 还将研究激肽释放酶-激肽系统的变化。 125 I-缓激肽结合研究将测量激肽受体的变化 数量和/或亲和力，以及钙动员的测定， 肌醇磷酸合成将测量第二信使的变化 生产 激肽释放酶（或激肽释放酶样）基因表达将被调节。 研究通过评估mRNA转录，和Na+-K+-Cl-的作用， IV效应中的共转运系统将通过抑制 在钾激发前与布美他尼共转运。 上皮细胞中离子转运的调节是复杂的， 涉及多种神经和荷尔蒙的影响 阐明 激肽释放酶-激肽系统对这些过程的贡献将 降低这种复杂性。 这些发现不仅与 基本细胞过程的定义，但也 了解人类疾病。