The role of tissue nonspecific alkaline phosphatase in brain endothelial cell homeostasis

项目总结 本应用目的是确定组织的非特异性碱性磷酸酶(TNAP)如何被酶催化 活动维持神经血管单位(NVU)内的脑血管功能。脑微血管内皮细胞 细胞(BMECs)构成脑微血管系统，是血脑的结构基础 屏障(BBB)和。BMECs通透性增加和完整性降低是两种常见的机制 在人类疾病中，脑血管功能通过这种方式受到损害。TnAP是一种高度浓缩的酶 在脑微血管中，其在脑内BMECs中的功能尚不清楚。我们的初步数据显示 TNAP活性刺激了一种新的信号机制，防止脑组织丢失 微血管完整性和通透性。这些耐人寻味的发现使我们提出了一个中心假设 在脑缺血期间，TNAP通过保持血脑屏障的完整性来维持NVU的动态平衡。我们将利用鼠标 用VE-钙粘蛋白-Cre驱动的内皮细胞条件缺失TNAP及其野生型 询问TnAP在BMEC中的作用。我们将比较年轻(4-5个月)和 老年(18~20月)小鼠脑内皮细胞TNAP对脑指数的增龄效应 内皮屏障通透性结合血管网络分析和功能行为结果。 目的1阐明脑内皮细胞TNAP在缺血性卒中NVU功能障碍中的作用 幼小的老鼠。我们将使用一过性中动脉闭塞模型来评估 脑血管结局和行为指标。AIM 2将确定对脑血管内皮细胞TNAP的影响 关于NVU的年龄相关性损害。这一目的将评估TNAP对衰老过程中BMEC功能的影响 缺血性卒中中可能存在的年龄依赖性交互作用。目标3将决定TNAP-RHO如何 相关蛋白激酶(ROCK)通路对屏障功能的调节以及药物对其的抑制作用 ROCK通路对缺血性卒中相关屏障完整性和功能缺陷的保护作用 无论是幼鼠还是老年鼠。综上所述，这项建议的研究将勾勒出一种新的机制，通过 哪种脑内皮细胞TNAP酶活性可保护缺血性卒中患者的NVU功能并改善其功能 卒中后功能恢复。总体结果将有助于我们对基本情况的有限理解 TNAP在BBB中的作用及其对人类健康和疾病中NVU动态平衡的贡献的生物学。

PROJECT SUMMARY The objective of this application is to determine how tissue nonspecific alkaline phosphatase (TNAP) enzymatic activity maintains cerebrovascular function within the neurovascular unit (NVU). Brain microvascular endothelial cells (BMECs) comprise the cerebral microvasculature and serve as the structural foundation of the blood-brain barrier (BBB) and. Increased permeability and diminished integrity of BMECs are two common mechanisms through which cerebrovascular function is compromised in human disease. TNAP is a highly enriched enzyme in cerebral microvessels whose function in brain BMECs is poorly understood. Our preliminary data demonstrate that TNAP activity stimulates a novel signaling mechanism which protects against the loss of cerebral microvascular integrity and permeability. These intriguing findings led us to propose the central hypothesis that TNAP maintains NVU homeostasis during cerebral ischemia by preserving BBB integrity. We will utilize mice with a VE-cadherin-Cre driven conditional deletion of TNAP in endothelial cells (VEcKO) and its wild type littermates to interrogate the role of TNAP in BMECs. We will compare responses in young (4-5 months) and aged (18-20 months) mice to assess the age-dependent effects of brain endothelial TNAP on indices of brain endothelial barrier permeability combined with vascular network analysis and functional behavioral outcomes. Aim 1 will elucidate the contribution of brain endothelial cell TNAP to NVU dysfunction in ischemic stroke in young mice. We will employ the transient middle artery occlusion model to assess quantitative differences in cerebrovascular outcomes and behavioral indices. Aim 2 will determine the impact of brain endothelial cell TNAP on age-dependent impairment of the NVU. This aim will assess the impact TNAP on BMEC function in aging and the putative age-dependent interactions in ischemic stroke. Aim 3 will determine how the TNAP-Rho associated kinase (ROCK) pathway regulates the barrier function and whether pharmacological inhibition of the ROCK pathway protects against the loss of barrier integrity and functional deficits associated ischemic stroke in both young and aged mice. Taken together, the studies in this proposal will delineate a novel mechanism through which brain endothelial cell TNAP enzyme activity preserves NVU function in ischemic stroke and improves functional recovery post-stroke. The overall results will contribute to our limited understanding of the basic biology of TNAP’s role at the BBB and its contribution to NVU homeostasis in human health and disease.