THE ROLE OF A-BETA SPECIES IN VASCULAR SMOOTH MUSCLE CELL AND CEREBRAL ARTERIOLE

A-β 物种在血管平滑肌细胞和脑小动脉中的作用

• 批准号: 8465919
• 负责人: GREGORY J ZIPFEL
• 金额: $ 32.09万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-01 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8465919
• 关键词: Affect; Alzheimer' s Disease; Amyloid; Antibodies; Apolipoprotein E; Applications Grants; Asses; Binding; Blood Vessels; Brain; Brain Infarction; Cause of Death; Cell Culture Techniques; Cell Surface Receptors; Cell physiology; Cerebral Amyloid Angiopathy; Cerebral Ischemia; Cerebrovascular Circulation; Cerebrum; Data; Dementia; Deposition; Endothelial Cells; Functional disorder; Future; Genetic; Genetically Engineered Mouse; Goals; Grant; Immunotherapy; Impaired cognition; Impairment; In Vitro; Infarction; LDL-Receptor Related Protein 1; Link; Mediating; Memory; Methods; Mitochondria; Molecular; Mus; NADPH Oxidase; Outcome; Oxidative Stress; Pathology; Pathway interactions; Patients; Peptides; Phenotype; Play; Predisposing Factor; Predisposition; Property; Reactive Oxygen Species; Research Personnel; Risk; Risk Factors; Role; Smooth Muscle Myocytes; Staging; Stroke; Testing; Tg2576; Therapeutic; Transgenic Mice; United States; Vascular Endothelial Cell; aged; arteriole; base; cerebrovascular; effective therapy; heparanase; heparin proteoglycan; improved; in vivo; monomer; pre-clinical; prevent; public health relevance; research study; therapeutic development; therapy development

DESCRIPTION (provided by applicant): The role of A¿ species in vascular smooth muscle cell and cerebral arteriole dysfunction. Alzheimer's Disease (AD) is the leading cause of dementia; yet no therapy exists to slow or stop its progression. Recently, cerebrovascular (CV) pathology has been identified as a strong contributor to AD. Two key observations suggest that amyloid-¿ peptide (A¿) may play a role by either causing or increasing the susceptibility to cerebral ischemia. First, cerebral blood flow (CBF) is reduced in early stages of AD, and the reactivity of cerebral blood vessels is impaired - both of which have been linked to the vasoactive properties of A¿. Second, most AD patients develop A¿ deposits not only in brain but also in vessels - a condition known as cerebral amyloid angiopathy (CAA). CAA is a powerful risk factor for brain infarction and dementia, and is associated with severe CV dysfunction. A2 exists in several forms including soluble monomers (such as A¿40 and A¿42), soluble oligomers (toxic intermediate species), and insoluble fibrils (principle component of CAA). The former (primarily A¿40) and the latter (fibrillar A2 in the form of CAA) have been shown to powerfully alter CV function, while the vascular effects of A2 oligomers are not known. Our preliminary data suggest that the manner and extent to which monomeric A2 vs. fibrillar A2 cause CV dysfunction is different. We find that A¿ monomers cause a hyper-contractile vascular phenotype that is due to endothelial cell (EC) and vascular smooth muscle cell (VSMC) dysfunction that is mediated via reactive oxygen species (ROS), while A¿ fibrils in the form of CAA cause a hypo-contractile vascular phenotype that is primarily due to VSMC dysfunction that is mediated via ROS. We also identified a previously unrecognized contribution of ROS to CAA formation. The long-term objective of the proposed project is to test the central hypothesis that A¿ species powerfully and adversely affect the cerebral circulation by inducing VSMC-mediated arteriole dysfunction via an ROS- mediated pathway. The specific aims are 1) to determine whether A¿ species cause differential CV effects (hyper- vs. hypo-contractile impairment); 2) to determine the ROS pathways by which A¿ species cause VSMC and cerebral arteriole dysfunction; and 3) to determine the manner and extent to which ROS contribute to CAA formation, and to assess the functional benefits of reducing CAA via anti-ROS strategies. Methods used will include a) in vitro assessment of VSMC function after application of exogenous A¿ species; b) in vivo assessment of cerebral arteriole function in transgenic mice producing endogenous A¿ species; c) immunotherapy with anti-A¿ antibodies that bind A¿40, A¿42, A¿ oligomers, and/or A¿ fibrils; d) pharmacologic and genetic inhibition of NADPH oxidase; d) pharmacologic and genetic inhibition of the A2-binding cell surface receptors, LRP1 and HSPGs; and e) quantitation of CAA, A¿40, A¿42, APP, and ApoE. If successful, these studies will result in an improved understanding of the mechanisms underlying A¿-induced CV deficits and CAA formation. This will likely facilitate development of therapies targeting A¿ and its downstream effectors, which may ultimately improve the outcome of patients with AD, CAA, or both.

描述（由申请人提供）：A 物种在血管平滑肌细胞和脑小动脉功能障碍中的作用。 阿尔茨海默病 (AD) 是导致痴呆症的主要原因；但尚无疗法可以减缓或阻止其进展。最近，脑血管 (CV) 病理学已被确定为 AD 的重要促成因素。两个关键的观察结果表明，淀粉样蛋白肽 (A¿) 可能通过引起或增加脑缺血的易感性而发挥作用。首先，AD 早期阶段脑血流量 (CBF) 减少，脑血管反应性受损 - 这两者都与 A¿ 的血管活性特性有关。其次，大多数 AD 患者不仅在大脑中而且在血管中出现 A 沉积，这种情况称为脑淀粉样血管病 (CAA)。 CAA 是脑梗塞和痴呆的重要危险因素，并与严重的心血管功能障碍有关。 A2 以多种形式存在，包括可溶性单体（例如 A'40 和 A'42）、可溶性低聚物（有毒中间体）和不溶性原纤维（CAA 的主要成分）。前者（主要是 A¿40）和后者（CAA 形式的纤维状 A2）已被证明可以强有力地改变 CV 功能，而 A2 寡聚物的血管效应尚不清楚。我们的初步数据表明，单体 A2 与纤维状 A2 导致 CV 功能障碍的方式和程度不同。我们发现，A¿单体会导致血管收缩过度表型，这是由于活性氧（ROS）介导的内皮细胞（EC）和血管平滑肌细胞（VSMC）功能障碍所致，而CAA形式的A¿原纤维会导致血管收缩不足表型，这主要是由于ROS介导的VSMC功能障碍。我们还发现了 ROS 对 CAA 形成的一个以前未被认识到的贡献。 该项目的长期目标是测试中心假设，即 A¿ 物种通过 ROS 介导的途径诱导 VSMC 介导的小动脉功能障碍，从而对脑循环产生强大而不利的影响。具体目标是 1) 确定 A¿ 物种是否会引起不同的 CV 效应（收缩过度与收缩受损）； 2)确定A¿物种引起VSMC和脑小动脉功能障碍的ROS途径； 3) 确定ROS促进CAA形成的方式和程度，并评估通过抗ROS策略减少CAA的功能益处。使用的方法包括a)应用外源A¿后VSMC功能的体外评估； b) 体内评估产生内源性A¿物种的转基因小鼠的脑小动脉功能； c)用结合AK 40、AK 42、AK寡聚物和/或AK原纤维的抗AK抗体进行免疫疗法； d) NADPH氧化酶的药理和遗传抑制； d) A2结合细胞表面受体、LRP1和HSPG的药理和遗传抑制； e) CAA、A¿40、A¿42、APP 和 ApoE 的定量。如果成功，这些研究将有助于更好地理解 A 诱导的 CV 缺陷和 CAA 形成的机制。这可能会促进针对 A¿ 及其下游效应器的疗法的开发，最终可能改善 AD、CAA 或两者兼而有之的患者的预后。