Role of PEPT2 in Peptide/Mimetic Disposition-Dynamics

描述(申请人提供)：细胞、分子和生理学研究为从机制上理解PEPT2的结构、功能和定位做出了重大贡献。然而，这些实验方法往往受到体外设计和缺乏血液供应、重叠的底物特异性以及多种转运系统的作用的限制，其中一些在研究时是未知的。因此，即使不是不可能，也很难定义单个特定基因产物的功能及其相对于存在于感兴趣组织或器官中的其他可能的蛋白质的重要性。这一竞争性更新申请的长期目标是确定PEPT2的生理和药理作用及其相关性，PEPT2是一种营养和药物转运体。我们的工作假设是PEPT2是主要的转运体，负责多肽和多肽类药物在体内的处置和动态，特别是大脑和肾脏。为了验证这一假说，提出了以下具体目标：目的1：确定PEPT2在影响多肽和多肽类药物的体内药代动力学、组织分布和全身暴露方面的作用和相对重要性；目的2：确定PEPT2对肽从脑脊液中流出的区域性影响及其对脑内药理反应的影响；目标3：表征PEPT2在发育小鼠脑实质中的细胞定位和功能活性。通过结合膜、细胞、免疫定位和在野生型和PEPT2基因缺失小鼠中的整体动物研究，这些研究将极大地促进我们对PEPT2(相对于其他潜在的转运体)在体内的作用、意义和多肽底物和药物的载体转运的理解。这些研究还可能提供难得的洞察力，了解具有遗传多态的人类受试者多肽/模拟动力学和反应的可变性。最后，拟议的研究可能对基于多肽的药物的设计、给药和靶向大脑治疗严重的中枢神经系统疾病具有重要意义。LAV描述：这个项目将确定一种特定的转运蛋白PEPT2如何影响多肽和多肽类药物在肾脏和大脑中的处置。这些研究的结果将提高治疗感染、高血压和癌症的药物的安全性和有效性，并促进治疗脑部疾病(如阿尔茨海默病、艾滋病)的新药的开发。

DESCRIPTION (provided by applicant): Cellular, molecular and physiological studies have made major contributions toward a mechanistic understanding of PEPT2 structure, function and localization. However, these experimental approaches are often limited by an in vitro design and lack of blood supply, overlapping substrate specificities, and the contribution of multiple transport systems, some of which are unknown at the time of study. As a result, it is difficult, if not impossible, to define the function of a single specific gene product and its significance in relation to other possible proteins that are present in the tissue or organ of interest. The long-term objectives of this competing renewal application are to define the physiological and pharmacological roles and relevance of PEPT2, a nutrient and drug transporter. Our working hypothesis is that PEPT2 is the primary transporter responsible for the disposition and dynamics of peptides and peptide-like drugs within the body, particularly the brain and kidney. To test this hypothesis, the following specific aims are proposed: Aim 1: To define the role and relative importance of PEPT2 in affecting the in vivo pharmacokinetics, tissue distribution and systemic exposure of peptides and peptide-like drugs; Aim 2: To determine the regional influence of PEPT2 on peptide efflux from the cerebrospinal fluid and its influence on pharmacologic response in the brain; Aim 3: To characterize the cellular localization and functional activity of PEPT2 in the brain parenchyma of developing mice. By combining membrane, cellular, immunolocalization and whole animal studies in wild type and PEPT2 null mice, the proposed studies will greatly advance our understanding of the in vivo role, significance and vectorial transport of peptide substrates and drugs by PEPT2 (as opposed to other potential transporters). These studies may also provide rare insight into the variability of peptide/mimetic kinetics and response in those human subjects with genetic polymorphisms. Finally, the proposed studies may have important implications for the design, delivery and targeting of peptide-based Pharmaceuticals to the brain for severe CNS disorders. Lav Description: This project will determine how a specific transporter, PEPT2, affects the disposition of peptides and peptide-like drugs in the kidney and brain. Results from these studies will improve the safety and efficacy of drugs for infection, hypertension and cancer, and facilitate the development of new drugs for brain disorders (e.g., Alzheimer's disease, AIDS).