Modifying endothelial Piezo 1 function to improve brain perfusion in AD/ADRD

以下建议是建立在我们最近的新发现基础上的，这些新发现显示了内皮Piezo 1在脑血中的关键作用。 脑血流（CBF）调节和大脑健康。Piezo 1是一种机械敏感性离子通道，其门控Ca 2+和Na+内流以响应 膜拉伸或增加的剪切力。在外周血管系统中，内皮细胞Piezo 1被激活， 流动/剪切，并通过Ca 2+依赖性机制促进血管舒张。我们现在提供新的初步数据 表明内皮细胞Piezo 1的选择性丧失促进静息CBF的减少（灌注不足）， 内皮细胞（EC）的药理学活化Piezo 1促进CBF（充血）增加。我们的数据进一步显示 慢性EC Piezo 1功能丧失（LOF）的后果包括内皮细胞相关基因的上调， 炎症和小胶质细胞/巨噬细胞募集（scRNAseq），广泛的小胶质细胞增生， 白色物质损伤。 特别是关于AD/ADRD，β-淀粉样蛋白（Ab）肽（例如Ab 40、Ab 42）已显示可急性降低Piezo 1 对流动/剪切活化的敏感性。这些发现提供了一种有趣的可能性，即淀粉样变性病可能损害 EC Piezo 1介导的CBF调节。我们的初步数据支持这一可能性，因为我们显示， 症状前和症状性TgAPP小鼠中的EC Piezo 1依赖性充血。此外，通过分析公众 从AD和认知正常患者的snRNAseq数据中，我们发现了与减少的 AD患者脑EC中的流量和Piezo 1依赖性信号传导。总之，这些数据表明，EC Piezo 1是至关重要的 EC Piezo 1功能障碍可加重脑灌注不足和衰老 和AB驱动的病理学 在拟议的项目中，我们将定义EC Piezo 1 LOF如何有助于衰老中的脑血管病理学， 淀粉样变性和探索EC Piezo 1功能获得（GOF）作为改善解决方案的新策略。我们的整体 假设EC Piezo 1 LOF增强衰老和Ab介导的病理，EC Piezo 1 GOF可以恢复 脑血管功能，并提供对衰老和Ab介导的认知下降的恢复力。目标1将定义大脑如何- 特异性EC Piezo 1 LOF导致衰老和淀粉样变性小鼠模型中的脑病理学。我们将使用两个TgAPP鼠标 模型淀粉样变性的不同方面的细胞系（Tg 2576和TgSwDI）。目标2将通过以下方式利用增强CBF的能力 EC Piezo 1 GOF恢复CBF调节，提供脑血管弹性，减缓衰老和AB相关疾病的进展 衰老和淀粉样变性小鼠模型的脑病理学和认知能力下降。我们将选择性诱导Piezo 1 GOF， 年轻和老年WT小鼠以及TgAPP小鼠在症状前和症状阶段的脑内皮。 目标1和2的完成将采用CBF和脑血管功能的体内测量的组合，测量 EC Piezo 1通道功能、白色物质束的3D定量成像、脑和血管免疫/组织化学 分析和行为研究。所有研究将在两种性别中进行。如果成功，这些研究将建立EC Piezo 1是一个有价值的治疗靶点，可增强脑灌注和减少认知能力下降。

The following proposal is built on our recent novel findings showing a critical role for endothelial Piezo1 in cerebral blood flow (CBF) regulation and brain health. Piezo1 is a mechanosensitive ion channel that gates Ca2+ and Na+ influx in response to membrane stretch or increased shear force. In the peripheral vasculature, endothelial Piezo1 is activated by increased flow/shear and promotes vasodilation through Ca2+-dependent mechanisms. We now provide novel preliminary data demonstrating that selective loss of endothelial Piezo1 promotes a decrease in resting CBF (hypoperfusion), while pharmacological activation of endothelial cell (EC) Piezo1 promotes increased CBF (hyperemia). Our data further show that the consequences of chronic EC Piezo1 loss of function (LOF) include endothelial upregulation of genes associated with inflammation and microglia/macrophage recruitment (scRNAseq), widespread microgliosis, and development of white matter injury. In specific regard to AD/ADRD, beta-amyloid (Ab) peptides (e.g. Ab40, Ab42) have been shown to acutely reduce Piezo1 sensitivity to flow/shear activation. These findings offer the intriguing possibility that conditions of amyloidosis may impair EC Piezo1-mediated CBF regulation. Our preliminary data support this possibility, as we show progressive impairment of EC Piezo1-dependent hyperemia in pre-symptomatic and symptomatic TgAPP mice. Additionally, by analyzing public snRNAseq data from AD and cognitively normal patients, we found a transcriptional signature consistent with reduced flow- and Piezo1-dependent signaling in EC from brain of AD patients. Together, these data suggest that EC Piezo1 is vital for normal CBF regulation and that the dysfunction of EC Piezo1 can exacerbate cerebral hypoperfusion and worsen age and Ab-driven pathology. In the proposed project, we will define how EC Piezo1 LOF contributes to cerebrovascular pathology in aging and amyloidosis and explore the novel strategy of EC Piezo1 gain of function (GOF) as an ameliorative solution. Our overall hypothesis is that EC Piezo1 LOF potentiates aging and Ab-mediated pathology and that EC Piezo1 GOF can restore cerebrovascular function and provide resilience to aging and Ab-mediated cognitive decline. Aim 1 will define how brain- specific EC Piezo1 LOF leads to brain pathology in mouse models of aging and amyloidosis. We will use two TgAPP mouse lines that model different aspects of amyloidosis (Tg2576 and TgSwDI). Aim 2 will leverage the ability to enhance CBF via EC Piezo1 GOF to restore CBF regulation, provide cerebrovascular resilience, and slow progression of aging and Ab-related brain pathology and cognitive decline in mouse models of aging and amyloidosis. We will induce Piezo1 GOF selectively in brain endothelium of young and aged WT mice and in TgAPP mice at pre-symptomatic and symptomatic stages. Completion of Aims 1 and 2 will employ a combination of in vivo measures of CBF and cerebrovascular function, measures of EC Piezo1 channel function, 3D quantitative imaging of white matter tracts, brain and vascular immuno/histochemical analyses, and behavior studies. All studies will be performed in both sexes. If successful, these studies will establish EC Piezo1 as a valuable therapeutic target for enhancing brain perfusion and reducing cognitive decline.