Cerebrovascular endothelial cilia in the pathogenesis and therapy of Alzheimer's disease

初级纤毛是以微管为基础的细胞器，从血管内皮细胞表面延伸到感觉 细胞外信号提示和流体剪切力。纤毛功能障碍(纤毛病)与许多 遗传性疾病，表现出广泛的症状，包括高血压(HTN)和认知和 记忆障碍。我们证明了初级内皮纤毛不能感知和传输液体 切应力可导致一氧化氮(NO)缺乏，引起血管性HTN。HTN可引起脑微血管病变 内皮机械应激，损伤神经血管单位，最终导致认知障碍， 导致阿尔茨海默病(AD)的发展。此外，NO的生物合成减少 通过增加β-淀粉样蛋白(A-β)的沉积，促进AD患者的慢性再生障碍性贫血。然而，分子 HTN和AD的发病机制尚不完全清楚，从而限制了我们的 预防这种疾病的开始和发展的能力。最近的研究发现了特定的mAChR- 调控通路是AD治疗的新靶点。乙酰胆碱受体(MAChRs)也是 在心血管系统中表达，并能调节血压和NO的生物合成。然而， 纤毛、mAChR信号和HTN在AD发病机制中的联系从未被研究过 在此之前。主要受我们最近发现的AChM3R定位于初级纤毛的支持，我们提出了一种 大胆的想法来研究脑血管纤毛受体在BP和BP中的病理生理作用 在活体AD中。这一应用程序旨在推进这一概念，即在AD的早期阶段，纤毛减少- 内皮源性A-β在脑血管壁介导的NO生物合成和沉积 HTN和AD发病的重要机制。我们产生了血管特异的AChM3R和 Tg737 KO小鼠，其中AChM3R和Tg737(纤毛发生的重要基因)从 血管内皮细胞。有趣的是，这些小鼠的血压升高，与NO的产生减弱有关，并且 认知功能改变。这些研究证实了原生纤毛来源的生理意义。 不能长期控制血管和认知功能。在这个提案中，我们阐述了假设 内皮纤毛AChM3R通过减少NO的生物合成参与AD的进展。在AIM 1、在3xTgAD模型中，我们将研究AChM3R或纤毛从血管内皮细胞中缺失对A？ 蓄积、血管反应性和脑血管完整性/功能。我们还将测试小说的效果 药物调节剂促进睫状肌AChM3R介导的NO生物合成。在目标2中，我们将 在3xTgAD模型中检测脑血管纤毛和AChM3R KO在BP和AD表现中的作用。 我们预计，该项目的成功完成将为利用内皮细胞提供新的机会 MAChRs作为旨在预防HTN有害影响的治疗干预的分子靶点 脑血管和认知功能。

Primary cilia are microtubule-based organelles, extending from the surface of vascular endothelial cells to sense extracellular signaling cues and fluid-shear stress. Cilia dysfunctions (ciliopathies) have been linked to numerous genetic disorders, and manifest a broad range of symptoms, including hypertension (HTN) and cognitive and memory dysfunction. We demonstrated that the inability of primary endothelial cilia to sense and transmit fluid shear stress can lead to nitric oxide (NO) deficiency and cause vascular HTN. HTN can cause brain microvascular endothelial mechanical stress, damage the neurovascular unit, and ultimately induce cognitive impairment, contributing to the progression of Alzheimer’s disease (AD). In addition, decreased biosynthesis of NO contributes to CAA in AD patients through increased deposition of beta amyloid (Aβ). However, the molecular mechanisms underlying the pathogenesis of HTN and AD are incompletely understood thereby limiting our ability to prevent initiation and progression of this disease. Recent studies have identified specific mAChR- regulated pathways as novel therapeutic targets for AD. Muscarinic acetylcholine receptors (mAChRs) are also expressed throughout the cardiovascular system and can regulate BP and NO biosynthesis. However, the connection between cilia, mAChR signaling, and HTN in the pathogenesis of AD has never been investigated before. Supported primarily by our recent discovery of the AChM3R localization to primary cilia, we propose a bold idea to look at the pathophysiological roles of cerebrovascular ciliary receptors in BP and in AD in vivo. This application is designed to advance the concept that in early stages of AD, diminished cilia- mediated NO biosynthesis and deposition of endothelium-derived Aβ in cerebral blood vessel wall is an important mechanism contributing to pathogenesis HTN and AD. We generated vascular-specific AChM3R and Tg737 KO mice, in which AChM3R and Tg737 (important for ciliogenesis) were specifically deleted from the vascular endothelia. Interestingly, these mice developed high BP, associated with attenuated NO production, and altered cognitive function. These studies demonstrated the physiological significance of primary cilia-derived NO in the long-term control of vascular and cognitive function. In this proposal, we formulated the hypothesis that endothelial ciliary AChM3R contributes to AD progression through diminished NO biosynthesis. In Aim 1, we will study the effect of AChM3R or cilia deletion from vascular endothelia in 3xTgAD model on Aß accumulation, vascular reactivity, and brain vascular integrity/function. We will also test the effect of novel pharmacological modulators on enhancing ciliary AChM3R-mediated NO biosynthesis. In Aim 2, we will examine the role of cerebrovascular cilia and AChM3R KO in BP and AD manifestations in the 3xTgAD model. We anticipate that successful completion of this project will offer new opportunities to utilize endothelial mAChRs as molecular targets for therapeutic interventions designed to prevent detrimental effects of HTN on cerebrovascular and cognitive function.