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ApoE4, neurovascular injury and cognitive impairment

ApoE4、神经血管损伤和认知障碍

基本信息

批准号：
10419353
负责人：
Costantino Iadecola
金额：
$ 84.69万
依托单位：
WEILL MEDICAL COLL OF CORNELL UNIV
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-04-01 至 2027-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10419353
关键词：
Age-associated memory impairment Aging Alleles Alzheimer&apos s Disease Alzheimer&apos s disease related dementia Alzheimer&apos s disease risk Apolipoprotein E Astrocytes Automobile Driving Bilateral Blood - brain barrier anatomy Blood Vessels Blood flow Bone Marrow Brain Brain Hypoxia-Ischemia Carotid Stenosis Carrier Proteins Cerebrovascular Circulation Cerebrovascular Disorders Cerebrum Chimera organism Cognitive Consensus Corpus Callosum Dementia Development Disease Enzymes Exhibits Female Fluorescence Functional disorder Gene Targeting Genetic Histopathology Human Hypoxia Image Impaired cognition Individual Inflammation International Knowledge LDL-Receptor Related Protein 1 Lesion Macrophage Activation Mediating Modeling Molecular Mus Myelogenous Myeloid Cells Oxidative Stress Perfusion Photons Play Predisposition Production Reactive Oxygen Species Regulation Risk Risk Factors Role Source Testing United States National Institutes of Health Variant Vascular Cognitive Impairment Vascular Diseases White Matter Disease Work apolipoprotein E-3 apolipoprotein E-4 autocrine base blood-brain barrier disruption cerebrovascular cognitive function cognitive testing experimental study genetic risk factor genetic variant insight lipid transport macrophage male mouse model neocortical neurovascular neurovascular injury new therapeutic target novel novel strategies receptor sex therapeutic target vascular cognitive impairment and dementia vascular factor white matter white matter damage white matter injury

项目摘要

ApoE is a lipid transport protein enriched in brain and present in three allelic variants (e2, e3, e4). Homozygosity for the e4 allele (e4/e4) is the main genetic risk factor for Alzheimer’s disease, but ApoE4 carriers also have increased risk for white matter lesions in both vascular cognitive impairment and Alzheimer’s disease and related dementias. Subcortical and periventricular white matter damage is a major cause of age-related cognitive impairment, but the mechanisms remain elusive. Located at the borderzone between separate arterial territories, the deep white matter is highly vulnerable to hypoxia-ischemia. ApoE4 carriers have reduced cerebral blood flow, whereas mice expressing human ApoE4 exhibit a profound disruption of key mechanisms regulating the delivery of blood flow to the brain. These findings raise the possibility that such cerebrovascular dysregulation renders the deep white matter more susceptible to hypoxia-ischemia. Perivascular macrophages (PVM), brain resident myeloid cells closely apposed to the outer wall of cerebral pial and penetrating vessels, can produce ApoE, are enriched in ApoE receptors, and are a powerful source of vascular oxidative stress and inflammation. Therefore, we hypothesize that PVM-derived ApoE4 acts in an autocrine manner on PVM to produce vascular oxidative stress and inflammation, leading to neurovascular dysfunction and increased susceptibility to white matter injury. Since NOX2 is the main source of reactive oxygen species in macrophages and TRPM2 channels are critical for macrophage activation and neurovascular dysfunction, we will also examine their role. We will test the following hypotheses: (a) PVM are both a source and target of the ApoE4 mediating neurovascular dysfunction; (b) PVM TRPM2 channels and NOX2 mediate ApoE4-induced vascular oxidative stress and inflammation leading to neurovascular dysfunction; (c) PVM-derived ApoE4 is responsible for the increased susceptibility to oligemic WM damage through NOX2 and TRPM2 channels. Studies are conducted in young and old mice of both sexes with targeted replacement of mouse ApoE with human ApoE3 or 4. Deep white matter injury is produced in the corpus callosum by bilateral carotid artery stenosis using microcoils. Cutting-edge approaches are used, including 3-photon excited fluorescence to image the deep white matter and a novel mouse model enabling conditional gene targeting in PVM. These approaches allow us to assess microvascular perfusion and damage in the deep white matter in mice with ApoE4, NOX2, or TRPM2 deletion in PVM. These studies will provide insight into the mechanisms underlying the impact of ApoE4 on white matter damage and may unveil new therapeutic targets for one of the leading causes of cognitive impairment and dementia.

ApoE是一种富含大脑的脂质转运蛋白，存在于三种等位基因变体中（e2, e3, e4）。