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

项目摘要 本申请的目的是确定组织非特异性碱性磷酸酶（TNAP）如何酶促 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（BMEC）构成脑微血管系统并作为血脑的结构基础 屏障（BBB）。BMEC的渗透性增加和完整性降低是两种常见的机制 在人类疾病中，脑血管功能通过其受损。TNAP是一种高度富集的酶 在脑微血管中，其在脑BMEC中的功能知之甚少。我们的初步数据显示 TNAP活性刺激了一种新的信号传导机制， 微血管完整性和渗透性。这些有趣的发现使我们提出了一个中心假设， TNAP通过保持BBB的完整性来维持脑缺血期间NVU的稳态。我们将利用老鼠 用内皮细胞中VE-钙粘蛋白-Cre驱动的TNAP条件性缺失（VEcKO）及其野生型 同窝仔询问TNAP在BMEC中的作用。我们将比较年轻人（4-5个月）和 年龄（18-20个月）小鼠，以评估脑内皮TNAP对脑指数的年龄依赖性影响。 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将阐明脑内皮细胞TNAP在缺血性卒中NVU功能障碍中的作用， 年轻的老鼠我们将采用短暂性中动脉闭塞模型来评估 脑血管结局和行为指标。目的2将确定脑内皮细胞TNAP的影响 NVU的年龄依赖性损伤。这一目标将评估TNAP对衰老过程中BMEC功能的影响 以及缺血性卒中中年龄依赖性相互作用的假设。目标3将确定TNAP-Rho 相关激酶（ROCK）途径调节屏障功能，以及是否对 ROCK通路可防止缺血性卒中相关的屏障完整性丧失和功能缺陷。 年轻和年老的老鼠。总而言之，本提案中的研究将通过以下方式描绘一种新的机制 其脑内皮细胞TNAP酶活性在缺血性中风中保持NVU功能并改善 中风后的功能恢复总体结果将有助于我们对基本的 TNAP在BBB中的作用及其对人类健康和疾病中NVU体内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.