Pericyte control of capillary perfusion in the Alzheimer's disease brain

阿尔茨海默病大脑中毛细血管灌注的周细胞控制

基本信息

批准号：
10655813
负责人：
Andy Y Shih
金额：
$ 89万
依托单位：
SEATTLE CHILDREN'S HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-04-15 至 2028-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10655813
关键词：
Actins Actomyosin Address Affect Agonist Alzheimer like pathology Alzheimer&apos s Disease Alzheimer&apos s disease brain Alzheimer&apos s disease model Alzheimer&apos s disease pathology Alzheimer&apos s disease related dementia Architecture Behavioral Biology Blood Vessels Blood capillaries Blood flow Brain Cells Central Nervous System Cerebral Amyloid Angiopathy Cerebrovascular Circulation Cerebrum Chronic Cognition Collaborations Contracts Cre driver Cytoskeleton Diameter Endothelin-1 Energy Supply Ensure GTP-Binding Proteins Gene Deletion Genes Genetic Health Heterogeneity Human Hyperemia Hypoxia Image Impaired cognition Impairment Knowledge Link Microscopy Modeling Mus Pathology Pattern Perfusion Pericytes Receptor Gene Receptor Signaling Regulation Research Research Personnel Resources Role Scientist Signal Transduction Signaling Protein Slice Smooth Muscle Smooth Muscle Myocytes Testing Therapeutic Thromboxane A2 Receptor Tissues Titrations Training Support Work abeta accumulation awake base behavioral outcome brain health brain tissue career cell type cerebral capillary cerebral hypoperfusion cerebral microvasculature constriction designer receptors exclusively activated by designer drugs experimental study genetic approach hypoperfusion imaging approach improved in vivo in vivo imaging in vivo two-photon imaging inhibitor innovation neuroinflammation next generation novel optogenetics pharmacologic pre-clinical research preclinical study protein activation receptor tool two-photon white matter

项目摘要

In Alzheimer's disease and Alzheimer's disease related dementias (AD/ADRD), aberrant contraction of capillary pericytes contributes to cerebral hypoperfusion. However, our understanding of the vasoactive signals and intracellular mechanisms underlying pericyte contractility remains lacking. Pericytes express high levels of endothelin-1 type A receptors (ETAR) and thromboxane A2 receptors (TXA2R). Our central hypothesis is that ETAR and TXA2R signaling is essential to optimize blood flow through brain capillary networks, and that aberrant activity through these receptors during amyloid beta (A) accumulation contributes to hypoperfusion. To address this hypothesis, we will use an in vivo-ex vivo pipeline with innovative imaging approaches and a novel murine Cre-driver to genetically target CNS pericytes. The work will be conducted by investigators with complementary expertise in in vivo two-photon imaging of blood flow, ex vivo brain slice experiments, pericyte biology, and ETAR and TXA2R signaling mechanisms. Aim 1 will test the hypothesis that ETAR and TXA2R signaling in pericytes provides basal capillary tone and orchestrates optimization of flow through brain capillary networks. ETAR (ednra gene), and separately, TXA2R (tbxa2r gene), will be conditionally deleted in capillary pericytes of normal mice. In vivo deep two-photon imaging will be used to study capillary flow dynamics across cortical layers and into callosal white matter of awake mice. A battery of vascular metrics, tissue hypoxia, neuroinflammation, and behavioral outcomes will be assessed. Aim 2 will test the hypothesis that G-protein signaling downstream of ETAR and TXA2R requires actomyosin contractile machinery in capillary pericytes, despite low expression of α- smooth muscle actin. We will use chemogenetics to drive G-protein activation, as seen downstream of ETAR and TXA2R signaling. Pericytes will be chemogenetically contracted in ex vivo brain slices and blockers of actomyosin and cytoskeletal machinery will be administered to dissect their roles in pericyte contraction. Further, chemogenetic activation of CNS capillary pericytes in vivo will be characterized as a new model of cerebral hypoperfusion. Aim 3 will test the hypothesis that aberrant ETAR and TXA2R signaling drives deficiency in capillary perfusion and cognitive decline during A accumulation. Conditional genetic deletion of ETAR or TXA2R, and separately, chronic administration of ETAR/TXA2R inhibitors will be examined in two models of AD- like pathology (Tg-SwDi and 5xFAD). Effects on cerebral blood flow, brain health, and behavioral metrics will be examined. This project will advance our understanding of brain hypoperfusion in AD/ADRD by: (1) Deciphering mechanisms of pericyte contractility in the normal and AD brain; (2) leveraging a novel capillary pericyte-specific mouse line to dissect pericyte contributions to blood flow; (3) characterizing a novel model of capillary-driven hypoperfusion in vivo; (4) employing advanced in vivo imaging approaches to study deep capillary networks most strongly affected in AD/ADRD; (5) providing proof of concept preclinical studies to test if modulation of ETAR and TXA2R signaling in pericytes can improve capillary network flow and cognition in AD/ADRD.

在阿尔茨海默病和阿尔茨海默病相关痴呆症 (AD/ADRD) 中，毛细血管异常收缩然而，周细胞导致脑灌注不足。周细胞收缩性的细胞内机制仍然缺乏。内皮素-1 A 型受体 (ETAR) 和血栓素 A2 受体 (TXA2R) 我们的中心假设是 ETAR 和 TXA2R 信号传导对于优化脑毛细血管网络的血流至关重要，并且异常 β 淀粉样蛋白 (A) 积累期间通过这些受体的活性有助于解决灌注不足问题。根据这一假设，我们将使用具有创新成像方法和新型小鼠的体内-离体管道 Cre-driver 基因靶向中枢神经系统周细胞这项工作将由具有互补性的研究人员进行。体内血流双光子成像、离体脑切片实验、周细胞生物学和 ETAR 方面的专业知识目标 1 将检验周细胞中 ETAR 和 TXA2R 信号传导的假设。提供基础毛细血管张力并协调通过脑毛细血管网络的流量优化（ednra。基因），以及单独的TXA2R（tbxa2r基因），将在正常小鼠的毛细血管周细胞中被有条件地删除。体内深层双光子成像将用于研究穿过皮质层并进入的毛细血管流动动力学清醒小鼠的胼胝体白质。一系列血管指标、组织缺氧、神经炎症和目标 2 将测试 G 蛋白信号传导下游的假设。 ETAR 和 TXA2R 需要毛细血管周细胞中的肌动球蛋白收缩机制，尽管 α- 表达较低我们将使用化学遗传学来驱动 G 蛋白激活，如 ETAR 下游所示。和 TXA2R 信号传导将在离体脑切片和阻断剂中发生化学遗传学收缩。将使用肌动球蛋白和细胞骨架机制来剖析它们在周细胞收缩中的作用。体内中枢神经系统毛细血管周细胞的化学遗传学激活将被描述为一种新的脑模型目标 3 将检验异常 ETAR 和 TXA2R 信号传导缺陷的假设。 A 积累过程中毛细血管灌注和认知能力下降。ETAR 或条件性基因缺失。 TXA2R 以及单独的 ETAR/TXA2R 抑制剂的长期给药将在两种 AD 模型中进行检查例如病理学（Tg-SwDi 和 5xFAD）对脑血流、大脑健康和行为指标的影响。该项目将通过以下方式增进我们对 AD/ADRD 中大脑灌注不足的理解：(1) 解读。正常和 AD 大脑中周细胞收缩性的机制；（2）利用新型毛细血管周细胞特异性小鼠系解剖周细胞对血流的贡献；（3）表征毛细血管驱动的新模型 (4) 采用先进的体内成像方法研究深层毛细血管网络 (5) 提供概念验证临床前研究来测试是否调节周细胞中的 ETAR 和 TXA2R 信号传导可以改善 AD/ADRD 中的毛细血管网络流动和认知。