Organic Cation Transporter PMAT: Physiological Function and Role in Drug Disposit

有机阳离子转运蛋白 PMAT：生理功能和在药物处置中的作用

基本信息

批准号：
8529550
负责人：
Joanne Wang
金额：
$ 30.71万
依托单位：
UNIVERSITY OF WASHINGTON
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-08-01 至 2016-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8529550
关键词：
1-Methyl-4-phenylpyridinium Amines Animal Model Basic Science Biguanides Biology Blood Brain Cations Cell Line Cell membrane Cerebrospinal Fluid Chemicals Clinical Colitis Colon Development Diffusion Drug Targeting Drug or chemical Tissue Distribution Drug usage Exhibits Gastrointestinal tract structure Gene Deletion Genetic Goals Histamine H2 Receptors Hormones Human Hypoglycemic Agents In Vitro Inflammation Inflammatory Bowel Diseases Inflammatory Response Intestines Knockout Mice Knowledge Laboratories Lead Light Liver Location Mediating Metformin Molecular Morphology Mus Neurotoxins Neurotransmitters Oral Organic Cation Transporter Organic Cation Transporter 1 POU2F1 gene POU2F2 gene Paraquat Pathogenesis Pathway interactions Permeability Pharmaceutical Preparations Physiological Physiology Platinum Play Predisposition Process Resources Role Serotonin Signal Pathway Site Specificity Structure Structure of choroid plexus Substrate Specificity Therapeutic Tissue membrane Tissues Toxic effect Toxin Validation Work Xenobiotics absorption base blood cerebrospinal fluid barrier design disorder prevention drug development drug discovery gastrointestinal high throughput screening in vivo inhibitor/antagonist insight knockout animal monoamine mouse model novel small molecule solute tool uptake

项目摘要

DESCRIPTION (provided by applicant): Many drugs (e.g. biguanide antihyperglycemics, histamine H2 receptor blockers, platinum-based chemotherapeutics etc.) and toxins (e.g. MPP+, paraquat) are hydrophilic organic cations (OCs) that do not readily cross cell membranes by passive diffusion. Organic cation transporters play important roles in the disposition, efficacy and toxicity of these OC xenobiotics. These transporters are also likely to be involved in various physiological pathways through their uptake of endogenous bioactive amines. The plasma membrane monoamine transporter (PMAT) is a new polyspecific organic cation transporter first cloned and characterized in our laboratory. The physiologic substrates of PMAT are the monoamine neurotransmitters with serotonin (5- HT) being the most preferred substrate. PMAT also transports many structurally diverse cationic xenobiotics including the neurotoxin MPP+ and therapeutic drugs such as metformin. PMAT is highly expressed in the brain and the gastrointestinal tract, and has overlapping substrate specificity with organic cation transporters 1- 3 (OCT1-3). Our previous molecular and cellular work strongly supports a role of PMAT in 5-HT signaling pathways and in OC transport at barrier tissues including choroid plexus that forms the blood- cerebrospinal fluid (CSF) barrier. However, these studies are limited by their in vitro design, and the physiological function of PMAT and its in vivo significance in brain OC disposition remain undefined. We have recently created a novel PMAT knockout mouse model, which provides a unique resource to evaluate the roles and significance of PMAT in vivo. Using a chemical biology approach, we also identified a set of promising specific small molecule inhibitors for PMAT. More excitingly, the PMAT null mice exhibited physiological and histological abnormalities in the colon which could represent early signs associated with the development of inflammatory bowel disease. Because 5-HT is a key gut hormone known to be involved in the pathogenesis of inflammatory bowel disease, these observations suggest a protective role of PMAT against colitis likely through 5-HT mediated pathway. In this competing renewal application, we propose to use our novel animal model and unique chemical tools to investigate the physiological, pharmacological and pathological function of PMAT. In Aim 1, we will further characterize and validate highly potent and selective small molecule inhibitors for PMAT. In Aim 2, we will use our knockout animal model and specific chemical inhibitors to investigate the role of PMAT in mediating OC efflux at the blood-CSF barrier. Lastly, in Aim 3, we will investigate the pathogenic role of PMAT in the development of inflammatory response in the gut. The proposed studies will greatly enhance our understandings of the in vivo roles and significance of a novel organic cation transporter. These studies will shed new light on the determinants influencing brain disposition of OC drugs and toxins. Finally, our studies will elucidate the pathophysiologic role of PMAT in the gut and offer new insights into genetic factors influencing host susceptibility to inflammatory bowel disease.

描述（由申请人提供）：许多药物（例如双胍类降糖药、组胺 H2 受体阻滞剂、铂类化疗药物等）和毒素（例如 MPP+、百草枯）是亲水性有机阳离子 (OC)，不易通过被动方式穿过细胞膜。扩散。有机阳离子转运蛋白在这些 OC 异生物质的处置、功效和毒性中发挥着重要作用。这些转运蛋白还可能通过摄取内源性生物活性胺参与各种生理途径。质膜单胺转运蛋白（PMAT）是我们实验室首次克隆和表征的新型多特异性有机阳离子转运蛋白。 PMAT 的生理底物是单胺神经递质，其中血清素 (5-HT) 是最优选的底物。 PMAT 还转运许多结构多样的阳离子异生物质，包括神经毒素 MPP+ 和二甲双胍等治疗药物。 PMAT 在大脑和胃肠道中高表达，并且与有机阳离子转运蛋白 1-3 (OCT1-3) 具有重叠的底物特异性。我们之前的分子和细胞工作强烈支持 PMAT 在 5-HT 信号通路和屏障组织（包括形成血脑脊液 (CSF) 屏障的脉络丛）的 OC 转运中的作用。然而，这些研究受到体外设计的限制，PMAT 的生理功能及其在脑 OC 处置中的体内意义仍不清楚。我们最近创建了一种新型 PMAT 敲除小鼠模型，为评估 PMAT 在体内的作用和意义提供了独特的资源。使用化学生物学方法，我们还确定了一组有前途的 PMAT 特异性小分子抑制剂。更令人兴奋的是，PMAT 无效小鼠在结肠中表现出生理和组织学异常，这可能代表与炎症性肠病发展相关的早期迹象。由于 5-HT 是一种已知参与炎症性肠病发病机制的关键肠道激素，因此这些观察结果表明 PMAT 可能通过 5-HT 介导的途径发挥对结肠炎的保护作用。在这一竞争性的更新应用中，我们建议使用我们新颖的动物模型和独特的化学工具来研究 PMAT 的生理、药理和病理功能。在目标 1 中，我们将进一步表征和验证 PMAT 的高效选择性小分子抑制剂。在目标 2 中，我们将使用我们的基因敲除动物模型和特定化学抑制剂来研究 PMAT 在介导血脑脊液屏障处 OC 外流中的作用。最后，在目标 3 中，我们将研究 PMAT 在肠道炎症反应发展中的致病作用。拟议的研究将极大地增强我们对新型有机阳离子转运蛋白的体内作用和意义的理解。这些研究将为影响大脑对 OC 药物和毒素的处置的决定因素提供新的线索。最后，我们的研究将阐明 PMAT 在肠道中的病理生理学作用，并为影响宿主对炎症性肠病易感性的遗传因素提供新的见解。