Blood Brain Barrier Changes Induced by Pain

疼痛每年折磨着美国超过8500万人，造成巨大的痛苦，花费数十亿美元用于医疗和生产力损失。疼痛诱导的血脑屏障（BBB）功能障碍显著改变了用于治疗疼痛的临床相关药物向脑中的转运。此外，BBB功能障碍引发和/或加剧与疼痛和/或炎症相关的许多中枢神经系统（CNS）和非CNS疾病和病理，包括阿尔茨海默病、缺血性中风、关节炎、糖尿病、多发性硬化和动脉粥样硬化。不幸的是，大多数关于神经药物在CNS中分布的研究都是使用未经历疼痛和/或炎症的健康动物进行的。我们实验室的研究表明，由？角叉菜胶、福尔马林或完全弗氏佐剂增加了细胞旁BBB通透性，改变了临床上用于治疗疼痛的阿片类药物的多药耐药（MDR）P-糖蛋白（P-gp）表达和脑摄取。此外，我们发现外周炎性疼痛改变了关键的紧密连接（TJ）蛋白闭合蛋白，claudin-3，claudin-5和闭合蛋白1（ZO-1）的表达和定位，这些蛋白在限制BBB细胞旁转运中至关重要。所有类别的疼痛（急性、亚慢性和慢性）都可以由疼痛刺激或炎症原引发，其激发外周先天免疫应答和CNS介导的应答。外周先天免疫反应涉及炎症介质在炎症损伤部位的快速产生和局部释放。中枢神经系统对外周炎症疼痛的反应涉及胶质细胞活化、促炎细胞因子和生长因子的从头合成以及过度的疼痛传递（痛觉过敏）。该提案的总体目标是详细了解外周疼痛和炎症如何导致BBB结构和功能的变化，从而改变用于治疗疼痛和CNS疾病的重要药物向大脑的递送。我们的假设是，外周先天性免疫反应和CNS介导的外周炎性疼痛反应引起的变化，在微血管内皮细胞在BBB的关键TJ和MDR（P-gp）蛋白的表达和细胞内运输，这些变化严重影响BBB细胞信号转导，细胞旁通透性和外排转运。本基金的目的将使用我们实验室建立和工作的生物化学，分子，药理学和体内方法的组合进行研究。这一建议将阐明由疼痛和炎症引起的BBB变化的潜在机制，并将有助于发现新的治疗BBB功能障碍和疼痛的治疗靶点。公共卫生相关性：在美国，疼痛每年折磨着超过8500万人，造成巨大的痛苦，花费数十亿美元的医疗费用和生产力损失。疼痛诱导的血脑屏障（BBB）功能障碍显著改变了用于治疗疼痛的临床重要药物向脑中的递送。这项NIH拨款提案将研究疼痛和炎症诱导的BBB变化的关键机制，并将在帮助发现治疗BBB功能障碍和疼痛的新治疗药物方面发挥关键作用。

DESCRIPTION (provided by applicant): Pain afflicts more than 85 million people in the United States each year, causing tremendous suffering and costing billions of dollars in medical treatments and lost productivity. Pain-induced blood-brain barrier (BBB) dysfunction significantly alters transport into the brain of clinically relevant drugs used to treat pain. Moreover, BBB dysfunction initiates and/or exacerbates numerous central nervous system (CNS) and non-CNS diseases and pathologies associated with pain and/or inflammation, including Alzheimer's disease, ischemic stroke, arthritis, diabetes, multiple sclerosis and atherosclerosis. Unfortunately, most research on the distribution of neuropharmaceuticals to the CNS has been performed using naive, healthy animals not suffering from pain and/or inflammation. Studies from our laboratory show that peripheral inflammatory pain induced by ?-carrageenan, formalin or complete Freund's adjuvant, increases paracellular BBB permeability, alters multi-drug resistant (MDR) P-glycoprotein (P-gp) expression and brain uptake of opiates used clinically to treat pain. Additionally, we find that peripheral inflammatory pain alters expression and localization of the key Tight Junction (TJ) proteins occludin, claudin-3, claudin-5 and zona occludens 1 (ZO-1) which are critically important in restricting BBB paracellular transport. All categories of pain (acute, subchronic and chronic) can be initiated by a painful stimulus or inflamagen that elicits both a peripheral innate immune response and a CNS-mediated response. The peripheral innate immune response involves the rapid production and local release of inflammatory mediators at the site of injury of inflammation. The CNS response to peripheral inflammation pain involves glia activation, de novo synthesis of proinflammatory cytokines and growth factors, and exaggerated pain transmission (hyperalgesia). The overall goal of this proposal is to provide a detailed understanding of how peripheral pain and inflammation cause the changes in BBB structure and function that lead to altered delivery to the brain of important pharmaceuticals used to treat pain and CNS disease. Our hypothesis is that both the peripheral innate immune response and the CNS-mediated response to peripheral inflammatory pain elicit changes in the expression and intracellular trafficking of key TJ and MDR (P-gp) proteins in microvascular endothelial cells at the BBB, and that these changes critically affect BBB cell signaling, paracellular permeability and efflux transport. The aims of this grant will be investigated using a combination of biochemical, molecular, pharmacological and in vivo methods established and working in our laboratory. This proposal will elucidate underlying mechanism of BBB changes induced by pain and inflammation, and will facilitate discovery of novel therapeutic targets for treating both BBB dysfunction and pain. PUBLIC HEALTH RELEVANCE: Pain afflicts more than 85 million people in the United States each year, causing tremendous suffering and costing billions of dollars in medical treatments and lost productivity. Pain-induced blood-brain barrier (BBB) dysfunction significantly alters delivery into the brain of clinically important drugs used to treat pain. This NIH grant proposal will study key mechanisms of BBB changes induced by pain and inflammation, and will be critical in aiding the discovery of new therapeutic drugs for treating BBB dysfunction and pain.