Molecular Organization of Renal Organic Anion Transport

性状（由申请方提供）：肾脏是从体内排泄大量具有生理学、药理学和毒理学意义的阴离子化合物（包括β-内酰胺抗生素;核苷衍生的抗病毒化合物;非甾体抗炎药（NSAID）;以及阴离子螯合剂和重金属螯合物）的主要途径。此外，肾脏与肝脏一起在控制II相代谢的许多其他阴离子代谢物的血浆水平方面发挥关键的辅助作用。这些有机阴离子（OAs）的肾脏排泄主要由肾近端小管（RPT）细胞介导的跨上皮分泌过程控制。近年来，越来越多的证据支持这样的论点，即肾分泌的OA涉及许多单独的转运蛋白的协同活动，这些转运蛋白在RPT的基底外侧（管周）和顶端（管腔）膜中表达。虽然基底外侧的“进入步骤”现在已经相当好地理解，RPT的管腔膜代表了我们对肾OA分泌的理解的“月亮的阴暗面”。尽管事实上，至少有8个不同的转运蛋白已被证明是表达在管腔膜的RPT为这些潜在的“候选”管腔转运蛋白是他们的影响程度的肾OA分泌的理解。这里提出的实验代表了一个综合的研究计划，旨在确定一组管腔转运蛋白对肾OA分泌的贡献，即，多药耐药相关蛋白（MRPs）。我们结合联合收割机使用克隆转运蛋白和模型培养细胞系统的研究，采用完整的肾小管和完整的动物。我们将开发培养表达克隆转运蛋白的细胞的模型系统，以评估两种不同的基底外侧“有机阴离子转运蛋白”转运蛋白（OAT;即，OAT 1和OAT 3）和两种不同的管腔转运蛋白（即，MRP 2和MRP 4）。这些模型细胞将提供设计和解释使用分离的单个肾近端小管和全肾清除率测量的实验所需的数据，所述实验采用野生型小鼠和缺乏选定OA转运蛋白的遗传模型。这项研究计划的创新设计允许在生物组织的三个不同层次上评估分泌的机制基础：分子和细胞;上皮/组织;和整个器官/器官，并将首次开发一种观点，即管腔和基底侧事件在药物相互作用和肾毒性发展中的潜在作用。

DESCRIPTION (provided by applicant): The kidney is the principal means for excretion from the body of a vast array of anionic compounds of physiological, pharmacological and toxicological significance (including p-lactam antibiotics; nucleoside- derived antiviral compounds; non-steroidal anti-inflammatory drugs (NSAIDs); and anionic chelators and chelates of heavy metals). In addition, the kidney plays a critical auxiliary role with the liver in controlling plasma levels of many other anionic metabolites of Phase II metabolism. Renal excretion of these organic anions (OAs) is dominated by the processes of transepithelial secretion mediated by cells of the renal proximal tubule (RPT). In recent years, increasing evidence supports the contention that renal secretion of OAs involves the concerted activity of many separate transport proteins that are expressed in the basolateral (peritubular) and apical (luminal) membranes of RPTs. Although the basolateral 'entry step' is now reasonably well understood, the luminal membrane of the RPT represents 'the dark side of the moon' with respect to our understanding of renal OA secretion. Despite the fact that at least 8 distinct transporters have been shown to be expressed in the luminal membrane of RPT for none of these potential 'candidate' luminal transporters is the extent of their influence on renal OA secretion understood. The experiments proposed here represent an integrated program of study designed to establish the contribution to renal OA secretion of one group of luminal transporters, i.e., the multidrug resistance-associate proteins (the MRPs). We combine the use of cloned transport proteins and model cultured cell systems with studies that employ intact renal tubules and intact animals. We will develop model systems that cultured cells expressing cloned transport proteins to assess the relative contribution to secretion of two distinct basolateral 'organic anion transporters' transporters (OATs; i.e., OAT1 and OAT3) and two distinct luminal transporters (i.e., MRP2 and MRP4). These model cells will provide data required to design and interpret experiments using isolated single renal proximal tubules and whole renal clearance measurements that employ both wild type mice and genetic models that lack selected OA transporters. The innovative design of this research program permits assessment of the mechanistic basis of secretion at three distinct levels of biological organization: the molecular and cellular; the epithelial/tissue; and the whole organ/organismic, and will develop for the first time a view of the potential role of both luminal and basolateral events in drug-drug interactions and the development of nephrotoxicity.