Functional deficits in neurovascular coupling in Alzheimer's disease

项目摘要 阿尔茨海默病（AD）是美国的一个主要公共卫生负担，死亡人数持续上升， 急剧增加。虽然AD患者的脑血流量（CBF）显著降低，但血管病理生理学改变可能与AD的发病机制有关。 还没有完全确定。我们已经确定了两个神经血管耦合（NVC）机制， CBF的调节：电信号（由K+介导），快速（毫秒时间尺度），作用于 长距离和Ca 2+信号传导（由GqPCR激动剂介导），其缓慢（秒）并且局部作用。然而 这些NVC机制在AD中是如何改变的尚不完全清楚。因此，长期目标 该建议的一个主要目的是使用AD的家族性小鼠模型（5xFAD）来确定NVC中的功能缺陷， 机制，并设计治疗策略，以恢复这些障碍。初步数据显示， 由于Kir2.1通道功能受损，5xFAD小鼠中的电信号减少， 补充膜磷脂; PIP 2-Kir2.1通道功能的必需组分。因此，我们认为， 我有一个新的假设，即AD中功能性充血的缺陷是血管PIP 2耗竭的结果， 这会削弱血流的电信号和Ca 2+信号控制。因此，我将确定分子 PIP 2的缺失破坏这些过程的机制，并评估PIP 2补充是否 恢复CBF控制，并反过来改善5xFAD小鼠的认知功能。我将测试这个假设， 以下具体目标：1）阐明与AD中有缺陷的电信号相关的机制，2） 评估AD病理学对脑内皮Ca 2+活性的影响，以及3）确定PIP 2的作用 在AD中恢复NVC。为了实现这些具体目标，我将结合体内和体外尖端技术的联合收割机 行为测试的实验方法。总的来说，该提案将确定血管功能 基于AD和PIP 2的治疗性干预的缺陷，以恢复CBF，进而恢复 AD.该提案与NIH预防和有效治疗阿尔茨海默氏症的使命声明之一一致 到2025年的疾病。 目前的提案将有助于Amreen Mughal博士的职业发展，因为她从一个 博士后研究员到独立研究员。加上她在血管生物学方面的强大背景，Amreen 将在最先进的图像分析和行为测试方面发展新技能。Mark T.博士纳尔逊，一个专家 离子通道，Ca 2+信号和血管生物学，将指导Amreen的科学发展和转型 在这次获奖中，为了加强候选人的培训，该计划还招募了一名 职业顾问团队，包括Anne Joutel博士、Sayamwong Hammack博士和塞韦林Schneebeli博士。的 在NIH独立之路奖（K99/R 00）的支持下， 允许候选人发展自己的研究利基，并成功地过渡为独立的研究 调查员

PROJECT SUMMARY Alzheimer’s disease (AD) is a major public health burden in the United states with a death toll that continues to increase steeply. While cerebral blood flow (CBF) is substantially reduced in AD, the vascular pathophysiology is not yet entirely characterized. We have identified two neurovascular coupling (NVC) mechanisms essential in regulation of CBF: electrical signaling (mediated by K+), which is rapid (millisecond time scale) and acts over long distances, and Ca2+ signaling (mediated by GqPCR agonists), which is slow (seconds) and acts locally. Yet how- these NVC mechanisms are altered in AD is incompletely understood. Therefore, the long-term objective of this proposal is to use a familial mouse model of AD (5xFAD) to determine functional deficit in NVC mechanisms in AD and design therapeutic strategies to restore these impairments. Preliminary data show that electrical signaling is reduced in 5xFAD mice due to impaired Kir2.1 channel function and restored by supplementation of membrane phospholipid; PIP2—an essential component for Kir2.1 channel function. Hence, I have a novel hypothesis that deficit in functional hyperemia in AD is the result of vascular PIP2 depletion, which cripples electrical and Ca2+ signaling control of blood flow. Accordingly, I will determine the molecular mechanisms through which loss of PIP2 disrupts these processes and evaluate whether PIP2 supplementation restores CBF control and in turn, improve cognitive function in 5xFAD mice. I will test this hypothesis by executing the following specific aims: 1) Elucidate mechanisms associated with defective electrical signaling in AD, 2) Evaluate the impact of AD pathology on brain endothelial Ca2+ activity, and 3) Determine the effect of PIP2 restoration on NVC in AD. To execute these specific aims, I will combine of cutting edge in vivo and ex vivo experimental approaches with behavioral testing. Collectively, this proposal will identify vascular functional deficits in AD and PIP2 based therapeutic intervention for restoration of CBF and in turn, cognitive function in AD. This proposal aligns with one of the NIH mission statements to prevent and effectively treat Alzheimer's disease by 2025. This current proposal will contribute Dr. Amreen Mughal’s career development as she transitions from a postdoctoral fellow to an independent researcher. Adding to her strong background in vascular biology, Amreen will develop new skills in the state-of-the-art image analysis and behavioral testing. Dr. Mark T. Nelson, an expert in ion channels, Ca2+ signaling, and vascular biology, will mentor Amreen’s scientific development and transition to independence during this award. To enhance the Candidate’s training, the program additionally enlists a career advisory team, including Drs. Anne Joutel, Sayamwong Hammack, and Severin Schneebeli. The productive research environment with the backing of the NIH Pathway to Independence Award (K99/R00) will allow the Candidate to develop her own research niche and successfully transition as an independent research investigator.