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

下面的建议是建立在我们最近的新发现基础上的，这些发现表明内皮型Piezo1在脑血液中起着关键作用 血流(CBF)调节与大脑健康。PIEZO1是一种机械敏感的离子通道，它可以控制钙离子和钠离子的内流。 使薄膜拉伸或增加剪切力。在外周血管系统中，内皮细胞Piezo1通过增加 流动/剪切，并通过钙依赖机制促进血管扩张。我们现在提供新的初步数据 证明选择性丢失内皮细胞Piezo1促进静息CBF的减少(低灌注率)，而 内皮细胞(EC)Piezo1的药理激活促进了CBF的增加(充血)。我们的数据进一步表明 慢性EC Piezo1功能丧失(LOF)的后果包括内皮相关基因上调 伴随炎症和小胶质细胞/巨噬细胞募集(ScRNAseq)，广泛的小胶质细胞增生症，并发展为 脑白质损伤。 关于AD/ADRD，已证明β-淀粉样多肽(如Ab40、AB42)可显著降低Piezo1 对流动/剪切激活的敏感性。这些发现提供了一种耐人寻味的可能性，即淀粉样变性的条件可能会损害 EC Piezo1介导的CBF调节。我们的初步数据支持这种可能性，因为我们显示出 出现症状前和出现症状的TgAPP小鼠的EC Piezo1依赖性充血。此外，通过分析公共 来自AD和认知正常患者的SnRNAseq数据，我们发现一个转录签名与Reduced AD患者脑内皮细胞Flow和Piezo1依赖的信号转导。总之，这些数据表明EC Piezo1是至关重要的 对于正常的脑血流量调节，EC Piezo1的功能障碍会加剧脑灌流不足和年龄恶化 和抗体驱动的病理学。 在拟议的项目中，我们将定义EC Piezo1 LOF如何在衰老和脑血管病变中起作用 淀粉样变性和探索EC Piezo1功能增强(GOF)作为改善解决方案的新策略。我们的整体 假设EC Piezo1 LOF增强衰老和抗体介导的病理，EC Piezo1 GOF可以恢复 脑血管功能，并提供对衰老和抗体介导的认知功能下降的韧性。目标1将定义大脑如何- 特异性EC Piezo1 LOF导致衰老和淀粉样变性小鼠模型的脑病理。我们将使用两个TgAPP鼠标 模拟淀粉样变性不同方面的线条(Tg2576和TgSwDI)。目标2将利用通过以下方式增强CBF的能力 EC Piezo1 GOF恢复CBF调节，提供脑血管韧性，延缓衰老和抗体相关进展 衰老和淀粉样变性小鼠模型的脑病理和认知功能减退。我们将选择性地诱导Piezo1 GOF 青年和老年WT小鼠以及TgAPP小鼠症状前期和症状阶段的脑内皮细胞。 目标1和目标2的完成将采用体内CBF和脑血管功能的测量相结合的方法 EC Piezo1通道功能、白质束3D定量成像、脑和血管免疫/组织化学 分析和行为研究。所有的研究都将在两性中进行。如果成功，这些研究将建立EC PIEZO1是一种有价值的治疗靶点，可增强脑血流灌注，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.