MOLECULAR MECHANISMS OF DRUG/XENOBIOTIC ELIMINATION

描述（由申请人提供）：有机阴离子转运蛋白（OAT）家族介导多种环境毒素和临床重要药物的吸收、分布和排泄，包括抗hiv治疗药物、抗肿瘤药物、抗生素、抗高血压药和抗炎药，因此对哺乳动物物种的生存至关重要。已鉴定出5种OAT1、OAT2、OAT3、OAT4和OAT5，并在肾、肝、脑和胎盘中检测到表达。这些器官的OAT功能障碍显著地导致肾、肝、神经和胎儿的毒性和疾病。我们的长期目标是通过OAT途径确定药物/毒素处置的分子机制。在上一个赠款期间，取得了重大进展和生产力。我们绘制了OAT 1的膜拓扑。我们已经确定了对OAT功能至关重要的氨基酸残基。我们发现OAT1在肾lc - pk1细胞中形成同质寡聚物。上一个资助期的新发现促使在这次竞争性更新中建立了一个微调的研究计划和战略。我们建议验证中心假设，即燕麦在体内不仅形成同源寡聚复合物，而且形成异寡聚复合物，并且燕麦的运输活性是由它们的寡聚状态赋予的。概述具体目标（SAs）。在SA-1中，我们将确定OAT寡聚的性质（同质寡聚物与异质寡聚物）。在SA-2中，我们将评估OAT寡聚化在维持其功能中的重要性。在SA-3中，我们将剖析OAT寡聚化的分子决定因素。在SA-4中，我们将比较OAT同质和异质低聚物的药理和调控特性。结合生物化学，分子生物学和生物物理学的方法将被用于组织切片和培养细胞的拟议研究。从这些研究中获得的知识对于合理设计新药和抑制剂以最大化治疗效果和最小化毒性将是无价的，并且将允许深入了解肾、肝、神经和胎儿毒性和疾病的分子、细胞和临床基础。

DESCRIPTION (provided by applicant): The organic anion transporter (OAT) family mediates the absorption, distribution, and excretion of a diverse array of environmental toxins, and clinically important drugs, including anti-HIV therapeutics, anti-tumor drugs, antibiotics, anti-hypertensives, and anti-inflammatories, and therefore is critical for the survival of mammalian species. 5 OATs have been identified (OAT1, OAT2, OAT3, OAT4, and OAT5) and their expression detected in kidney, liver, brain and placenta. OAT dysfunction in these organs significantly contributes to the renal, hepatic, neurological and fetal toxicity and disease. Our long-term goal is to define the molecular mechanisms underlying drug/toxin disposition through the OAT pathway. During the previous grant period, significant progress and productivity have been achieved. We have mapped the membrane topology of OAT 1. We have identified the amino acid residues critical for OAT function. We have showed that OAT1 form homo-oligomer in kidney LLC-PK1 cells. The new findings from the previous grant period led to the establishment of a fine-tuned research plan and strategy in this competing renewal. We propose to test the central hypothesis that OATs form not only homo- but also hetero-oligomeric complexes in vivo and that transport activities of OATs are conferred by their oligomerization states. 4 Specific Aims (SAs) are outlined. In SA-1, we will determine the nature of OAT oligomerization (homo-versus hetero-oligomers). In SA-2, we will assess the importance of OAT oligomerization in maintenance of its function. In SA-3, we will dissect the molecular determinants of OAT oligomerization. In SA-4, we will compare the pharmacological and regulatory properties of OAT homo-and hetero-oligomers. Combined approaches of biochemistry, molecular biology, and biophysics will be employed for the proposed studies in tissue slices, and cultured cells. The knowledge gained from these studies will be invaluable toward the rational design of novel drugs and inhibitors to maximize therapeutic efficacy and minimize toxicity, and will permit insight into the molecular, cellular, and clinical bases of renal, hepatic, neurological and fetal toxicity and disease.