Peptide/Mimetic Transport Mechanisms in Choroid Plexus

脉络丛中的肽/模拟转运机制

• 批准号: 7058547
• 负责人: DAVID E SMITH
• 金额: $ 5.63万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-02-01 至 2006-01-09
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7058547
• 关键词: Xenopus oocyte; apical membrane; blood brain barrier; choroid plexus; immunologic assay /test; laboratory mouse; laboratory rat; membrane transport proteins; neuropeptides; oligopeptides; peptide analog; pharmacokinetics; protein isoforms; protein localization; protein structure function; protein transport; tissue /cell culture

DESCRIPTION (Verbatim from the application): In contrast to the intestine and kidney, little is known about the cellular and molecular mechanisms of peptide and peptidomimetic transport between blood and brain. This is unfortunate since the presence of tight junctions between the endothelial cella that form the blood-brain barrier (BBB) and the choroid plexus epithelial cells that form the blood-cerebrospinal fluid barrier (BCSFB) limit paracellular movement. Thus, specific transporters are required for the transcellular transport of hydrophilic compounds whether for the movement of nutrients into the brain or toxins out of the brain. The presence of peptide transporters within the brain (i.e., PEPT2 and PHT1) has generated considerable interest as to their precise anatomical location, role in neuropeptide homeostasis, significance in substrate trafficking, and potential as a drug delivery system through the blood brain and/or CSF barriers. Novel findings in our laboratory have established the functional and molecular presence of a high-affinity peptide transporter, PEPT2, in whole tissue rat choroid plexus. These preliminary results suggest that PEPT2 may play an important role in the uptake of peptides which function as neuromodulators, the clearance of degraded neuropeptides, and the efflux of some cephalosporin drugs from choroidal epithelium. Our working hypothesis is that PEPT2 is expressed in apical membranes of the choroid plexus and functions as the primary efflux pump in removing neuropeptide fragments and peptide-like drugs from cerebrospinal fluid. To test this hypothesis, the following specific aims are proposed: Aim 1. To define the functional characteristics of peptide-mediated transport in rat choroid plexus epithelial cells in primary culture; Aim 2. To determine the tissue distribution and membrane localization of specific oligopeptide transporters in mammalian brain; Aim 3. To develop and validate a mouse model in which the gene encoding PEPT2 has been ablated by targeted gene disruption. The long-term objectives of this competing renewal application are to define the cellular and molecular mechanisms involved in the transport of peptides and peptide-like drugs in choroid plexus. Combined with immunoloclization experiments and studies in PEPT2-deficient mice, the proposed studies will greatly advance our understanding of the role, significance and vectorial transport of peptide substrates by PEPT2 in brain (as compared to PHT1 and other potential transporters). Moreover, in addressing fundamental questions of peptide transporter activity, expression and significance, the proposed studies may have important implications for the treatment of CNS disorders (e.g., Alzheimer's disease, AIDS dementia, stroke, epilepsy, schizophrenia and cancer) and for providing new strategies in drug design, delivery and targeting to the brain.

描述（来自应用程序的逐字）：与肠道和 虽然肽在肾脏中的作用机制尚不清楚， 以及血液和脑之间的拟肽转运。这是不幸的，因为 形成血管内皮切拉之间紧密连接的存在， 血脑屏障（BBB）和脉络丛上皮细胞，形成 血-脑脊液屏障（BCSFB）限制细胞旁运动。因此，在本发明中， 特异性转运蛋白是跨细胞转运 亲水性化合物，无论是用于将营养物移入大脑， 毒素排出大脑脑内肽转运蛋白的存在 (i.e., PEPT 2和PHT 1）已经引起了相当大的兴趣， 解剖位置，在神经肽稳态中的作用， 底物运输，并作为药物输送系统的潜力，通过 血脑屏障和/或CSF屏障。我们实验室的新发现 建立了高亲和力肽的功能和分子存在 转运蛋白PEPT 2在大鼠脉络丛中的表达。这些初步 结果表明，PEPT 2可能在肽的摄取中起重要作用 作为神经调节剂，清除降解的神经肽， 某些头孢菌素类药物从脉络膜上皮的流出。我们的工作 假设PEPT 2在脉络丛的顶膜中表达 并在去除神经肽片段中起主要外排泵的作用， 从脑脊液中提取肽类药物。为了验证这一假设， 提出了以下具体目标：目标1。定义函数 大鼠脉络丛上皮细胞肽转运特性的研究 原代培养细胞;目的2.确定组织分布， 哺乳动物脑内特异性寡肽转运蛋白的膜定位; 目标3.开发并验证小鼠模型，其中编码PEPT 2的基因 已经被定向基因破坏消除了这一长期目标 竞争更新应用是定义细胞和分子 肽和肽样药物在体内的转运机制 脉络丛结合免疫定位实验研究， PEPT 2缺陷小鼠，拟议的研究将大大推进我们的研究。 了解肽的作用、意义和载体转运 脑中PEPT 2的底物（与PHT 1和其他潜在的 运输者）。此外，在解决肽的基本问题时， 转运蛋白活性、表达和意义，拟议的研究可能 对CNS疾病的治疗具有重要意义（例如， 阿尔茨海默病、艾滋病痴呆、中风、癫痫、精神分裂症和癌症） 并为药物设计、递送和靶向提供新的策略， 个脑袋