Cellular Mechanisms of Action of Mineralocorticoid Hormones

盐皮质激素作用的细胞机制

• 批准号: 7727756
• 负责人: JOHN P. JOHNSON
• 金额: $ 35.92万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-05-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7727756
• 关键词: Affect; Aldosterone; Amiloride; Animals; Apical; Biochemical; Biological Assay; Cardiovascular Diseases; Cell Culture Techniques; Cells; Chloride Ion; Chlorides; Cleaved cell; Colon; Cytoplasmic Vesicles; Deletion Mutagenesis; Disease; Distal; Duct (organ) structure; Early Endosome; Endosomes; Epithelial Cells; Epithelium; Equilibrium; Excretory function; Exocytosis; Funding; Genomics; Grant; Heart failure; Homeostasis; Hormones; Hypertension; Immunofluorescence Immunologic; Infusion procedures; Intake; Kidney; Lead; Link; Liquid substance; Maintenance; Mammals; Mediating; Membrane Microdomains; Methylation; Methyltransferase; Mineralocorticoids; Modeling; Molecular; Na(+)-K(+)-Exchanging ATPase; Nephrons; Oocytes; Pathway interactions; Phenotype; Physiological; Population; Post-Translational Protein Processing; Post-Translational Regulation; Probability; Process; Proteins; Proteomics; Pulmonary Cystic Fibrosis; Recycling; Regulation; Regulation of Exocytosis; Research; Research Design; Retrieval; Role; Site; Sodium; Sodium Channel; Specificity; Steroids; Stimulus; Surface; System; Time; Ubiquitin; Up-Regulation; Work; airway epithelium; apical membrane; collecting tubule structure; deprivation; epithelial Na+ channel; hemodynamics; inhibitor/antagonist; kidney cell; non-genomic; overexpression; public health relevance; research study; response; restoration; trafficking

DESCRIPTION (provided by applicant): Maintenance of extrecellular fluid volume homeostasis is essential for hemodynamic stability, and abnormalities of renal sodium handling have been linked to cardiovascular disease and hypertension. Ultimate regulation of sodium excretion occurs in the distal nephron via conductive transport through the amiloride sensitive epithelial Na+ channel (ENaC). ENaC expression and activity in the apical membrane of epithelial cells is the rate limiting step in Na+ reabsorption not only in the kidney collecting duct, but in airway epithelia and colon as well. Aldosterone is the major regulator of ENaC expression and activity in responsive epithelia. The long term objectives of this research are to define the mechanisms through which mineralocorticoid hormones regulate vectorial sodium transport in responsive epithelia and studies are designed to examine the mechanisms of aldosterone regulation of ENaC. Work in the current grant period has identified a specific methyltransferase which activates ENaC and knockdown of this protein blocks the early aldosterone response. Studies are now proposed to determine if this protein is required for early aldosterone action via genomic or non-genomic pathways and determine how aldosterone regulates its activity. We have demonstrated that ENaC trafficks to the apical membrane of epithelial cells in lipid rafts and developed a model of ENaC trafficking in cultured epithelial cells. Cells deprived of aldosterone develop a loss of Na+ reabsorptive activity along with a loss of the cellular recycling compartment for ENaC. The recycling compartment and Na+ reabsorptive phenotype are restored over time by aldosterone. Restoration of the ENaC recycling pathway is associated with adlosterone up-regulation of multiple proteins in the endosomal compartment. We will examine the mechanisms by which aldosterone regulates the apical expression of ENaC from endosomal and/or recycling pathways and determine what specific aldosterone-regulated proteins control the activity and expression of ENaC in endosomes and exocyst compartments to support apical translocation of ENaC in Na+ reabsorptive states. PUBLIC HEALTH RELEVANCE: Aldosterone is the major hormone which regulates sodium reabsorption in the kidney in mammals. Abnormalities of sodium handling can lead to diseases such as hypertension and heart failure and have been implicated in the progression of cystic fibrosis lung disease. These studies are designed to determine the cellular mechanisms by which aldosterone regulates sodium reabsorption in kidney cells.

描述（由申请人提供）：维持细胞外液体体积稳态对于血液动力学稳定性至关重要，肾脏钠处理异常与心血管疾病和高血压有关。钠排泄的最终调节是通过通过Amiloride敏感上皮Na+通道（ENAC）的导电转运在远端肾单位中发生的。上皮细胞的顶膜中的ENAC表达和活性是Na+重吸收的速率限制步骤，不仅在肾脏收集导管中，而且在气道上皮和结肠中。醛固酮是反应性上皮中ENAC表达和活性的主要调节剂。这项研究的长期目标是定义盐皮质激素激素在反应性上皮中调节矢量钠转运的机制，研究旨在检查醛固酮调节ENAC的机制。当前赠款期的工作已经确定了一种特定的甲基转移酶，该甲基转移酶激活该蛋白质的ENAC和敲低可阻止早期醛固酮反应。现在，提出了研究来确定通过基因组或非基因组途径早期醛固酮作用的蛋白质是否需要这种蛋白质，并确定醛固酮如何调节其活性。我们已经证明，脂质筏中上皮细胞的顶膜的ENAC运输，并开发了一种在培养的上皮细胞中运输的模型。被醛固酮剥夺的细胞会导致Na+重吸收活性以及ENAC的细胞回收室的丧失。醛固酮会随着时间的推移恢复回收室和Na+重吸收表型。 ENAC回收途径的恢复与内体隔室中多种蛋白质的脂肪素上调有关。我们将研究醛固酮从内体和/或回收途径调节ENAC的顶端表达的机制，并确定哪些特定醛固酮调节的蛋白控制了eNAC在内体和外囊肿室中的活性和表达，以支持Na+重新添加词的ENAC的顶端转运。公共卫生相关性：醛固酮是调节哺乳动物肾脏钠重吸收的主要激素。钠处理异常会导致高血压和心力衰竭等疾病，并与囊性纤维化肺部疾病的进展有关。这些研究旨在确定醛固酮调节肾细胞中钠重吸收的细胞机制。