Modulating P-glycoprotein to Enhance Neurodegenerative Drug Penetration of Brain

描述(由申请人提供)：在这项提案中，我们正在研究如何提高针对癫痫和阿尔茨海默病的药物的大脑生物利用度，这两种疾病是常见的和破坏性的神经疾病。我们正在探索可逆地调节血脑屏障(BBB)上P-糖蛋白(P-gp)活性的方法。体内研究表明，Valspodar(PSC833)对血脑屏障P-gp的药理抑制可增加P-gp底物抗癫痫药苯妥英在脑内的摄取。我们建议在治疗药物本身的基础上开发新型的P-gp二聚体前药抑制剂。一旦进入大脑，这些二聚体前药将恢复为已知的经批准的治疗剂。我们假设，二聚体前体药物抑制剂与治疗剂量的单体药物联合使用将有助于增加治疗药物在大脑中的水平，并可能降低患者的总剂量水平。我们相信，我们已经组建了一支具有丰富经验的个人投资团队，以实现每一个具体目标。具体目标1：我们将合成抗癫痫药物(苯妥英、苯巴比妥和拉莫三嗪)、抗阿尔茨海默病药物(加兰他明)和潜在抗阿尔茨海默病药物(格列卫)的前药物二聚体，这些药物通过无踪迹连接物连接。具体目标2：我们将使用体内过表达P-gp或表达P-gp的不同细胞株来评价前药二聚体对P-gp转运的抑制作用。具体目标3：我们将评价前药物二聚体对荧光底物柔红霉素、钙黄素-AM、BODIPY-FL-维拉帕米和罗丹明123在大鼠脑毛细血管中P-gp转运的抑制作用，并以治疗性单体为对照。在拟议的资助期结束时，我们将在脑内皮细胞和脑毛细血管模型中获得具有抗P-糖蛋白活性的二聚体前药。这项研究的长期目标将是监测AEDs和抗阿尔茨海默氏症药物与活性前体药物在癫痫小鼠模型中的脑渗透情况。治疗脑部疾病是有问题的，因为许多药物无法进入大脑。这种缺乏大脑穿透力的部分原因是在进入大脑之前，大脑屏障上的泵将药物清除。这项提议试图通过暂时阻断泵以允许药物进入大脑来解决这个问题。这些研究的完成有可能改善癫痫和阿尔茨海默病的治疗。

DESCRIPTION (provided by applicant): In this proposal, we are investigating ways to increase the brain bioavailability of agents targeted against epilepsy and Alzheimer's disease, two common and devastating neurological disorders. We are exploring ways to reversibly modulate the activity of P-glycoprotein (P-gp) at the blood brain barrier (BBB). It has been shown in vivo that pharmacological inhibition of P-gp at the blood brain barrier by valspodar (PSC833) increased the uptake of the anti-epileptic agent phenytoin, a P-gp substrate, in brains. We propose to develop novel dimeric prodrug inhibitors of P-gp based on the therapeutic agents themselves. Once into the brain, these dimeric prodrugs will revert to the known approved therapeutic agent. We hypothesize that co-administration of the dimeric prodrug inhibitor in conjunction with therapeutic doses of the monomeric drug would serve to increase the level of the therapeutic agent in the brain and potentially lower the overall patient dose level. We believe that we have assembled a team of PIs with extensive experience to address each of the Specific Aims. Specific Aim 1: We will synthesize prodrug dimers of anti-epilepsy drugs (AEDs) (phenytoin, phenobarbital and lamotrigine), an anti-Alzheimer's disease drug (galantamine) and a potential anti- Alzheimer's disease agent (Gleevec) that are tethered via traceless linkers. Specific Aim 2: We will evaluate inhibition of P-gp transport by the prodrug dimers using various cell lines that overexpress P-gp or express P-gp at endogenous in vivo levels. Specific Aim 3: We will evaluate inhibition of P-gp transport of the fluorescent substrates daunomycin, calcein-AM, Bodipy-FL-verapamil and rhodamine 123 in isolated rat brain capillaries by the prodrug dimers and will use the therapeutic monomers as controls. At the completion of the proposed funding period, we will have dimeric prodrugs with activity against P-glycoprotein in brain endothelial cell and brain capillary models. The long term goals of this research will be to monitor brain penetration of AEDs and anti-Alzheimer's drugs in combination with the active prodrugs in an epileptic mouse model. Treating brain diseases is problematic because a number of drugs are not able to enter the brain. This lack of brain penetration is caused in part by a pump at the barrier to the brain that removes drugs before brain entry. This proposal seeks to remedy this problem by blocking the pump temporarily to allow drugs to pass into the brain. Completion of these studies has the potential to improve treatment of epilepsy and Alzheimer's disease.