Molecular tools to decipher communication across the blood-brain barrier

项目摘要/摘要 血脑屏障(BBB)通过保护大脑免受血流的影响来维持大脑健康。这些 屏障的特性阻碍了几乎所有大脑疾病的治疗，代表了最大的 神经科学和药物输送方面的挑战。然而，有趣的是，最近的研究发现了各种 令人惊讶的外周对大脑功能的影响，暗示存在被低估的模式 通过BBB进行通信。事实上，虽然规范的血脑屏障特性，如细胞旁的紧密连接 和最小的小窝蛋白介导的跨细胞作用，已经通过几个标准示踪剂建立，它 目前尚不清楚这些示踪剂是否完全代表了血脑屏障与和 对它不断接触的数以千计的循环蛋白质和细胞具有渗透性。通过开发 方法标记和追踪血浆蛋白质组，我最近观察到了一个意想不到的程度和多样性 蛋白质进入健康成人大脑的能力。因此，我假设大脑的健康不仅仅是通过 血脑屏障不通透性--但通过血脑屏障积极促进的特定的血与脑沟通途径。 具体地说，我建议有三条逻辑路径来传递外围信息 跨越健康的血脑屏障：蛋白质直接运输到大脑；由 血脑屏障进入大脑；以及血脑屏障许可的外周免疫细胞进入大脑。通过组合 利用生物正交化学的蛋白质组标记技术，每个提出的目标都探索一个独立的目标 系统地揭示通过健康的血脑屏障传递的信号的身份和机制。我 将首先创建一个直接跨越血脑屏障的血浆蛋白目录，并量化它们的 渗透率(目标1)。我随后将通过推导信号来表征新的BBB中继功能 血脑屏障对周围提示做出反应而分泌到大脑中(目标2)。最后，我将阐明神经免疫 通过确定能够使免疫细胞健康地迁移到大脑中的BBB部位和分子进行监测 (目标3)。总之，这些研究将扩大我们对血脑屏障如何维持大脑健康和 开展新的研究，探索血脑屏障通透性蛋白和细胞在健康、衰老、 和疾病。我们的结果还将提供一套全面的功能靶点，以增强药物输送到 大脑，揭示了解和钝化神经炎症的新机制，并产生创新的工具 破译跨学科广泛使用的细胞间通信。

Project Summary/Abstract The blood-brain barrier (BBB) maintains brain health by protecting the brain from the bloodstream. These barrier properties frustrate the treatment of nearly all brain disorders, representing one of the largest challenges in neuroscience and drug delivery. Yet, intriguingly, recent studies have discovered a variety of surprising peripheral influences on brain function, hinting at the existence of underappreciated modes of communication across the BBB. Indeed, while canonical BBB properties, such as paracellular tight junctions and minimal caveolin-mediated transcytosis, have been established via a handful of standard tracers, it remains unclear whether these tracers fully represent the BBB’s physiological interactions with and permeability to the thousands of circulating proteins and cells it is constantly exposed to. By developing methods to tag and track the blood plasma proteome, I recently observed an unexpected degree and diversity of protein transport into the healthy adult brain. Thus, I hypothesize that brain health is maintained not just by BBB impermeability—but by specific routes of blood-to-brain communication actively facilitated by the BBB. Specifically, I propose that there are three logical routes for how peripheral information is communicated across the healthy BBB: the direct transport of proteins into the brain; the responsive relay of proteins made by the BBB into the brain; and the BBB-licensed migration of peripheral immune cells into the brain. By combining proteome tagging techniques with bioorthogonal chemistries, each proposed aim explores one independent route to systematically reveal the identities and mechanisms of the signals transmitted via the healthy BBB. I will begin by creating a first catalog of plasma proteins that directly cross the BBB and quantifying their permeabilities (Aim 1). I will subsequently characterize a new BBB relay function by deducing the signals the BBB secretes into the brain in response to peripheral cues (Aim 2). Lastly, I will elucidate neuroimmune surveillance by determining the BBB sites and molecules enabling healthy immune cell migration into the brain (Aim 3). Together, these studies will expand our understanding of how the BBB maintains brain health and enable new studies exploring the neurological functions of BBB-permeable proteins and cells in health, aging, and disease. Our results will also provide a comprehensive set of functional targets to enhance drug delivery to the brain, reveal new mechanisms to understand and blunt neuroinflammation, and generate innovative tools to decipher intercellular communication for broad use across disciplines.