Neuronal and vascular interactions in the CNS

项目总结/摘要： 身体中没有任何器官比大脑更依赖于持续的血液供应。的 循环系统对大脑的重要性可以通过大脑占大脑的2%这一事实来证明。 但它接收20%的心输出量。此外，大脑不包含局部燃料 储备，就像外围器官一样。在行为过程中，大脑区域被招募来执行特定的任务， 快速“上线”。大脑通过一个叫做神经血管耦合的过程来调节自己的血液供应， 其中神经活动迅速增加局部血流量以满足局部脑中的时刻变化 能源需求。神经血管偶联的损伤有助于神经变性和血管变性。 痴呆神经血管耦合也是功能性脑成像的基础，这是目前唯一的方法 来推断人类全脑神经元的激活。尽管了解大脑是如何 调节自身的血液供应，神经血管耦合的分子和细胞机制是 还不清楚。在这个提议中，我们已经开发了一种双光子体内成像范例， 同时测量神经活动（通过遗传编码钙指示器）和血管动力学 （血管直径和血流量）在清醒小鼠的单血管分辨率，使我们能够捕捉到 神经血管反应的自然刺激（晶须刺激）在高时间和空间分辨率， vivo.我们将联合收割机这种最先进的体内成像技术与强大的分子，电生理， 超微结构和遗传方法来阐明基本的细胞机制， 神经血管耦合我们的初步数据与在体内活成像和小鼠遗传学在桶皮质， 提示脑内内皮细胞在神经血管耦联中起着积极作用。传统上，EC 被认为是被动参与神经血管耦合，是一个同质的人口。我们 发现aECs和cECs显示分子和亚细胞差异，并在过程中发挥不同的作用。 神经血管耦合我们提出的工作将确定细胞，亚细胞和分子机制 来自血管树的不同节段的内皮细胞通过其启动、传递和实施 神经血管耦合具体来说，我们将展示如何沿着血管树不同类型的EC 介导神经血管耦合，从而连接神经活动和局部血流变化之间的点。 我们希望我们的能力，成像中枢神经系统小血管非侵入性清醒小鼠与高空间 和时间分辨率，沿着与其他复杂的技术，将使我们能够确定关键的分子 以及体内神经血管偶联的亚细胞机制。此外，我们的结构和 分子生物学的发现将为脑血管生物学领域提供可广泛使用的工具。最后， 这些数据将提供关键信息，以加速我们对中枢神经系统疾病相关疾病的理解和治疗。 小血管和血管性痴呆。

Project Summary/abstract: There is no organ in the body that more heavily depends on a continuous supply of blood than the brain. The importance of the circulatory system to the brain is demonstrated by the fact that the brain makes up 2% of total body mass but it receives 20% of cardiac output. Furthermore, the brain does not contain local fuel reserves, as peripheral organs do. During behavior, brain regions are recruited for specific tasks and must be brought “online” quickly. The brain regulates its own blood supply via a process called neurovascular coupling, in which neural activity rapidly increases local blood flow to meet moment-to-moment changes in regional brain energy demand. Impairments in neurovascular coupling contributes to neurodegeneration and vascular dementia. Neurovascular coupling is also the basis for functional brain imaging, which is currently the only way to infer brain-wide neuronal activation in humans. Despite the importance of understanding how the brain regulates its own blood supply, the molecular and cellular mechanisms underlying neurovascular coupling are still not clear. In this proposal, we have developed a two-photon in vivo imaging paradigm that can simultaneously measure neural activity (via a genetically encoded calcium indicator) and vascular dynamics (vessel diameter and blood flow) at single-vessel resolution in awake mice, enabling us to capture the neurovascular response to a natural stimulus (whisker stimulation) at high temporal and spatial resolution in vivo. We will combine this state-of-art in vivo imaging techniques with powerful molecular, electrophysiological, ultrastructural, and genetic approaches to elucidate the fundamental cellular mechanisms governing neurovascular coupling. Our preliminary data with in vivo live imaging and mouse genetics in the barrel cortex, suggest that endothelial cells (ECs) in the brain play active roles in neurovascular coupling. Traditionally, ECs were considered to be passively involved in neurovascular coupling, and to be a homogenous population. We found aECs and cECs display molecular and subcellular differences, and play distinct roles during neurovascular coupling. Our proposed work will identify the cellular, subcellular, and molecular mechanisms by which endothelial cells from different segments of the vascular tree initiate, transmit, and implement neurovascular coupling. Specifically, we will demonstrate how different type of ECs along the vascular tree mediate neurovascular coupling, thus connecting the dots between neural activity and local blood flow change. We expect that our ability to image CNS small blood vessels non-invasively in awake mice with high spatial and temporal resolution, along with other sophisticated techniques, will allow us to identify critical molecular and subcellular mechanisms that underlie neurovascular coupling in vivo. Moreover, our structural and molecular findings will provide tools that can be broadly used by the field to cerebrovascular biology. Finally, the data will provide critical information to accelerate our understanding and treatment of CNS diseases related to small vessels and vascular dementia.