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.

在阿尔茨海默氏病和阿尔茨海默氏病有关的痴呆症（AD/ADRD）中，毛细血管的异常收缩周细胞导致脑部灌注不足。但是，我们对血管活性信号和仍然缺乏细胞内机制。周细胞表达高水平内皮素-1 A型受体（ETAR）和血栓烷A2受体（TXA2R）。我们的中心假设是 ETAR和TXA2R信号传导对于优化通过脑毛细管网络的血流至关重要，并且这种异常淀粉样β（A）积累期间通过这些受体的活性导致灌注不足。解决这个假设，我们将使用创新的成像方法和一种新颖的鼠使用体内体内体内管道 Cre-Driver通常靶向CNS周围。这项工作将由调查人员进行完善体内双光子成像的专业知识，体内脑切片实验，周细胞生物学和ETAR 和TXA2R信号传导机制。 AIM 1将测试周细胞中ETAR和TXA2R信号传导的假设提供基本的毛细血管色调，并通过脑毛细管网络进行优化。 etar（埃德拉）基因）和分别是TXA2R（TBXA2R基因），将在正常小鼠的毛细血管期有条件地删除。体内深的两光子成像将用于研究皮质层的毛细血管流动动力学并进入醒着老鼠的白色事物。一系列血管指标，组织缺氧，神经炎症和将评估行为结果。 AIM 2将检验以下假设：G蛋白信号在下游 ETAR和TXA2R需要毛细管周细胞中的肌动球蛋白收缩机制，dospite低表达α- 平滑肌肌动蛋白。如Etar的下游，我们将使用化学遗传学驱动G蛋白激活和TXA2R信号传导。周细胞将在离体脑切片和阻滞剂的化学上收缩肌动球蛋白和细胞骨架机制将被施用，以剖析其在周细胞收缩中的作用。此外， CNS毛细血管周细胞体内的化学发生激活将被视为一种新的大脑模型灌注不良。 AIM 3将检验以下假设：异常ETAR和TXA2R信号导致缺乏症 A积累期间毛细血管灌注和认知下降。 ETAR或 TXA2R以及单独的ETAR/TXA2R抑制剂的慢性给药像病理学（TG-SWDI和5XFAD）。对脑血流，大脑健康和行为指标的影响检查。该项目将使我们对AD/ADRD中大脑灌注灌注的理解：（1）解密正常和广告大脑中周细胞收缩的机制；（2）利用一种新颖的毛细管周细胞特异性小鼠线以剖析周细胞对血流的贡献；（3）表征毛细管驱动的新型模型体内灌注不足；（4）采用先进的体内成像方法研究深毛细管网络广告/ADRD受到最大影响；（5）提供概念临床前研究证明，以测试是否调制周细胞中的ETAR和TXA2R信号传导可以改善AD/ADRD中的毛细管网络流量和认知。