Supplement: Stalled capillary flow affects protein clearance by modulating interstitial fluid flow

补充：毛细血管血流停滞通过调节间质液流动影响蛋白质清除

基本信息

批准号：
10617575
负责人：
Nozomi Nishimura
金额：
$ 13.27万
依托单位：
CORNELL UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-05-15 至 2024-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10617575
关键词：
Abeta clearance Acute Affect Alzheimer&apos s Disease Alzheimer&apos s disease model Alzheimer&apos s disease pathology Alzheimer&apos s disease patient Amyloid Amyloid beta-Protein Amyloid beta-Protein Precursor Antibodies Award Basement membrane Binding Biological Assay Blood Vessels Blood capillaries Blood flow Brain Brain region Cell Adhesion Molecules Cerebrovascular Circulation Chronic Cognitive deficits Color Complement Convection Data Dependovirus Disease Disease Progression Elements Endothelial Cells Endothelium Ensure Enzymes Equilibrium Exhibits Extracellular Protein Feedback Fluorescence Microscopy Generations Genes Genetic Engineering Health Hippocampus (Brain)Hour Image Impairment Incidence Individual Inflammatory Injections Intercellular Fluid Ischemia Knock-in Knock-in Mouse Knock-out Lead Leukocytes Link Liquid substance Lymphatic Maps Measurement Mechanics Membrane Proteins Memory Meningeal lymphatic system Modeling Molecular Morphologic artifacts Motion Mus Neurons Oxidative Stress Pathology Pericytes Photons Production Proteins Reactive Oxygen Species Role Side Signal Transduction Speed Stream Stroke Testing Therapeutic Time Tissues Tracer Vasodilation Viral Vector Virus Diseases Wild Type Mouse Work abeta accumulation abeta deposition adeno-associated viral vector arteriole brain volume cell injury cell type cerebral capillary cognitive function constriction design fluid flow fluorescence imaging glymphatic system hypoperfusion improved in vivo intravital imaging mouse model neuropathology neutrophil next generation novel novel therapeutics parent grant pressure prevent protein transport prototype relating to nervous system therapeutic target two-photon venule

项目摘要

Project Summary Cerebral blood flow (CBF) is reduced in Alzheimer’s disease (AD) patients and mouse models by ~20%, but there remains a limited understanding of the mechanisms causing this hypoperfusion or the potential therapeutic benefit of rescuing CBF deficits. Under the previous award, chronic in vivo two-photon excited fluorescence microscopy was used to study CBF in mouse models of AD. While no blood flow disruption in cortical arterioles or venules was observed, blood flow was found to be stalled in ~2% of cortical capillaries in mouse models of AD, as compared to ~0.4% in wild type controls. These capillary stalls appeared early in disease progression, were caused by arrested neutrophils, and had outsized impacts on CBF because they decreased flow speed in up- and down-stream vessels. Antibodies against the neutrophil surface protein Ly6G were serendipitously found to reduce the incidence of capillary stalls immediately, leading to a rescue of two-thirds of the CBF deficit, and, remarkably, to improved memory function within hours. Preliminary data further link this capillary stalling to cellular damage from reactive oxygen species (ROS). In this competitive renewal, the mechanisms underlying neutrophil arrest in capillaries in mouse models of AD and the consequences of improving CBF on AD-related pathology are explored. First, three different hypotheses about the mechanism of neutrophil arrest in capillary segments are tested: a focal constriction of the capillary by a pericyte that prevents neutrophil passage; binding of the neutrophil to increased inflammatory adhesion molecules on endothelial cells; or binding of the neutrophil to basement membrane and adhesion molecules exposed at widened gaps between endothelial cells. Second, the molecular and cellular origin of the ROS that leads to neutrophil arrest is determined using cell type-specific knockouts of ROS producing enzymes. Third, the impact of long-term CBF rescue on the deposition of amyloid- beta (Aβ), a driver of AD pathology, and on neuropathology will be quantified. Critical for this study are recently- developed knock-in mouse models of AD that may better capture the feedback of CBF reductions on expression of amyloid precursor protein (APP), which is cleaved to produce Aβ. Finally, cutting-edge three-photon excited fluorescence microscopy is used to enable imaging of the hippocampus to determine the role of capillary stalling in CBF deficits in one of the first regions of the brain that exhibits AD pathology. The hypothesis that brain hypoperfusion in AD is due to neutrophil arrest in capillaries is both novel and strongly supported by the findings under the previous award. The work proposed in this competitive renewal would uncover the mechanisms underlying that neutrophil arrest, which could suggest therapeutic targets to improve CBF that would be complementary to anti-amyloid and other treatment approaches for AD.

项目摘要在阿尔茨海默氏病（AD）患者和小鼠模型中，脑血流（CBF）降低了约20％，但人们对引起这种灌注灌注或潜在疗法的机制的理解仍然有限营救CBF定义的好处。在先前的奖项下，慢性体内双光子激发荧光显微镜用于研究AD小鼠模型中的CBF。虽然皮质artioles中没有血流破坏或观察到静脉 AD，野生型对照中的约0.4％。这些毛细管摊位出现在疾病进展的早期，是由被捕的中性粒细胞引起的，并且对CBF产生了巨大影响，因为它们降低了流速向上和下游视频。偶然发现针对中性粒细胞表面蛋白Ly6g的抗体为了立即减少毛细管摊位的事件，导致营救三分之二的CBF赤字，并值得注意的是，要在数小时内提高内存功能。初步数据进一步链接了此毛细管的停滞活性氧（ROS）受到细胞损伤。在这种竞争性更新中，基础机制 AD小鼠模型中毛细血管中的中性粒细胞停滞，以及改善CBF对AD相关的后果探索了病理学。首先，关于毛细血管中嗜中性粒细胞阻滞机制的三个不同的假设测试了段：毛细血管对毛细血管的焦点收缩，可防止中性粒细胞传递；结合中性粒细胞增加内皮细胞上炎症粘附分子的增加；或中性粒细胞的结合在内皮细胞之间宽大的间隙处暴露于地下膜和粘合分子。第二，使用细胞类型特异性的ROS的分子和细胞起源。 ROS产生酶的敲除。第三，长期CBF救援对淀粉样蛋白沉积的影响将量化AD病理学和神经病理学的驱动因素（Aβ）。最近这项研究至关重要 - 开发的AD敲入鼠标模型，可以更好地捕获CBF降低表达的反馈淀粉样蛋白前体蛋白（APP）的蛋白质，该蛋白被裂解以产生Aβ。最后，尖端的三光子激动荧光显微镜用于启用海马的成像，以确定毛细管停滞的作用在CBF中，在表现出AD病理学的大脑的第一个区域之一中定义了。大脑的假设 AD中的灌注不足是由于毛细血管中的嗜中性粒细胞停滞既新颖又受到发现的强烈支持根据先前的奖项。在这种竞争更新中提出的工作将揭示机制嗜中性粒细胞逮捕的基础，这可能建议改善CBF的治疗靶标的完全采用AD的抗淀粉样蛋白和其他治疗方法。