Treatment of Alzheimer’s Disease using Ultrasound-Targeted Microbubble Cavitation-Mediated Blood Brain Barrier Opening to Facilitate Drug Delivery to the Brain

项目摘要/摘要 阿尔茨海默病(AD)是一种毁灭性的、进行性的神经退行性疾病，影响着数百万人 然而，目前还没有治愈的方法，治疗选择也非常有限。在其他方面有希望的失败 治疗阿尔茨海默病的药物可能部分是由于对大脑的渗透性差和/或需要较大的全身剂量来 达到治疗性的大脑集中，导致偏离目标的效果。解决血脑屏障(BBB)问题 超声靶向微泡空化(UTMC)作为一种新的治疗方法正在被探索 AD的战略。在这种方法中，低强度超声被应用于静脉注射的超声造影剂。 药剂(微泡)穿过大脑的微循环。UTMC导致一过性内皮细胞 屏障高渗透性，允许通过血脑屏障进行特定部位的治疗药物输送。当UTMC展示的时候 作为一种增加血脑屏障通透性的技术，其潜在的机制尚不完全清楚， 最终限制了临床翻译。我的首要目标是，针对大脑的UTMC提供了 为治疗阿尔茨海默病而加强血脑屏障药物输送的方法。为了方便临床翻译这篇文章 平台，我的建议将确定介导UTMC诱导的血脑屏障高通透性的机制并利用 UTMC在体内提供针对抗体斑块的治疗药物的目的如下：(1)鉴定 UTMC导致一过性血脑屏障高通透性的机制。UTMC在脐静脉中的应用 体外培养的内皮细胞可以改变细胞骨架动力学，导致内皮细胞间的缝隙， 它可以增加细胞旁通透性，并与钙离子内流接触的细胞有关，以及 远离空化的微气泡。将这些发现推广到血脑屏障，我假设UTMC介导的 CA2的内流破坏了脑微血管内皮细胞之间紧密和粘连的连接，还可能 导致邻近星形胶质细胞内钙离子介导的变化。血脑屏障体外接触共培养Transwell模型的建立 将用于研究内皮细胞和星形胶质细胞的功能和结构变化(共聚焦显微镜) 在UTMC之后。(2)确定UTMC介导的血脑屏障开放，结合药物治疗， 将降低抗体斑块负荷，改善治疗窗口。我假设UTMC介导的血脑屏障 开放将减少特定药物所需的剂量，该药物旨在降低抗体斑块沉积，从而 最大限度地减少偏离目标的影响。该药物将被给予，UTMC将被应用于小鼠的大脑 AD的模型。脑抗体斑块将通过连续的脑PET成像进行量化。我已经组装了一个不同寻常的 由导师和合作者组成的多学科团队，以及具体的课程和研讨会，以获得 在AD生物学、超声声学、成像和小鼠AD模型方面的必要内容专业知识。穿过 与我的导师见面并进行我的实验，我将在严谨的 实验设计、数据分析和演示。我的全面训练计划将为我做好准备 实现我的职业目标，成为一名内科科学家，从事从板凳到床边的翻译研究。

PROJECT SUMMARY/ABSTRACT Alzheimer’s disease (AD) is a devastating, progressive, neurodegenerative disease that affects millions of Americans, yet there is no cure, and there are very limited treatment options. Failure of otherwise promising drugs for AD may be due, in part, to poor penetration into the brain and/or large systemic dose requirements to achieve therapeutic brain concentrations, resulting in off-target effects. To address blood brain barrier (BBB) impenetrability, ultrasound-targeted microbubble cavitation (UTMC) is being explored as a new treatment strategy for AD. In this approach, low intensity ultrasound is applied to intravenously injected ultrasound contrast agents (microbubbles) as they traverse the microcirculation of the brain. UTMC causes transient endothelial barrier hyperpermeability, allowing for site-specific delivery of therapeutics across the BBB. While UTMC shows promise as a technique to increase BBB permeability, its underlying mechanisms are incompletely understood, ultimately constraining clinical translation. My overarching goal is that UTMC directed to the brain offers an approach to enhance drug delivery across the BBB for treatment of AD. To facilitate clinical translation of this platform, my proposal will determine mechanisms mediating UTMC-induced BBB hyperpermeability and utilize UTMC for delivering therapeutics directed at Ab plaques in vivo in the following Aims: (1) To identify mechanisms by which UTMC causes transient BBB hyperpermeability. UTMC applied to umbilical vein endothelial cells in vitro has been shown to change cytoskeletal dynamics, leading to inter-endothelial cell gaps, which can increase paracellular permeability, and was associated with Ca2+ influx into cells in contact with, and remote from, cavitating microbubbles. Extending these findings to the BBB, I hypothesize that UTMC-mediated Ca2+ influx disrupts tight and adherens junctions between brain microvascular endothelial cells, and may also lead to Ca2+-mediated changes in adjacent astrocytes. A contact co-culture in vitro transwell model of the BBB will be used to study changes in function and structure (confocal microscopy) of endothelial cells and astrocytes after UTMC. (2) To determine whether UTMC-mediated BBB opening, in combination with drug therapy, will lower Ab plaque burden and improve the therapeutic window. I hypothesize that UTMC-mediated BBB opening will decrease the dose required for a specific drug designed to lower Ab plaque deposition, thereby minimizing off-target effects. The drug will be administered, and UTMC will be applied to the brain in a mouse model of AD. Brain Ab plaques will be quantified by serial brain PET imaging. I have assembled an exceptional multidisciplinary team of mentors and collaborators, along with specific coursework and seminars, to acquire the necessary content expertise in AD biology, ultrasound theranostics, imaging, and murine AD models. Through meetings with my mentors and conducting my experiments, I will acquire experiential lessons in rigorous experimental design, data analysis, and presentation. My comprehensive training plan will prepare me to achieve my career goal of becoming a physician-scientist pursuing bench to bedside translational research.