Vascular Smooth Muscle Notch Signaling in Arterial Patterning and Function

描述(由申请人提供)：血管平滑肌细胞(VSMCs)支持血管系统发育、出生后成熟和功能所需的形成、结构完整性和化学响应性。在血管生成过程中，内皮细胞(ECs)结合形成原始的管状毛细血管网络，VSMCs的招募促进血管成熟或血管新生重塑，受ECs和VSMCs内操作的信号和转录程序的复杂相互作用控制。在生理和病理条件下，这些活动的平衡对血管的形成和功能起着至关重要的调节作用。PI以前发表的研究表明，体内VSMCs中规范的Notch信号的抑制导致了不正确的脑动脉构型以及无法形成成熟的动脉血管壁。这些发现证实了Notch信号在正常血管形成中的VSMC自主作用，并暗示了Notch信号在动脉构型和侧支动脉形成中的重要作用。此外，这些解剖结构紊乱与诱发脑缺血的小鼠发生脑血管功能不全和中风的风险增加有关。综上所述，这些观察结果支持我们的中心假设，即VSMCs中的Notch信号提供了动脉血管系统正确组织和功能所需的指导性线索。本研究的目的是进一步全面研究Notch信号在体外和体内VSMC生物学中的作用。在目标1中，将对含有Notch信号缺陷的VSMCs的小鼠胚胎进行研究，以绘制出生前发育期间新生血管的时空组织图，作为观察到的出生后解剖异常的基础。目的2将通过检测血管对生理和化学刺激的反应，探讨Notch信号缺陷的VSMCs在天然血管中的功能动力学。最后，目标3将通过评估Notch信号缺陷的VSMC的血管生成和血管重塑作用的体外研究，部分地检验血管结构和VSMC功能改变的分子基础。公共卫生相关性：血管平滑肌细胞(VSMCs)是形成合格的血管系统所必需的。Notch信号是调节VSMC功能的重要分子途径，Notch信号缺陷与人类以中风和先天性心血管异常为特征的血管综合征有关。这一建议用于在机械水平上确定Notch信号在VSMC中的确切作用，从而赋予血管系统适当的组织和功能。这些研究的结果将为治疗外周和脑动脉疾病等血管功能不全的新疗法奠定基础。

DESCRIPTION (provided by applicant): Vascular smooth muscle cells (VSMCs) support the formation, structural integrity and chemical responsivity required for development, post-natal maturation and function of the blood vasculature. Following the process of vasculogenesis wherein endothelial cells (ECs) coalesce to form a primitive, tubular capillary network, recruitment of VSMCs promotes vessel maturation or angiogenic remodeling governed by a complex interplay of signaling and transcriptional programs operating within ECs and VSMCs. The balance of these activities critically regulates vascular formation and function under physiologic and pathologic conditions. Previous studies published by the PI revealed that suppression of canonical Notch signaling in VSMCs in vivo resulted in improper cerebral arterial patterning as well as failure to form mature arterial vessel walls. These findings identified a VSMC-autonomous role for Notch signaling in the formation of competent vessels and implicated an important role for Notch signaling in arterial patterning and collateral artery formation. In addition, these anatomical derangements were associated with an increased risk for cerebrovascular insufficiency and stroke in mice subjected to induced ischemia. Taken together, these observations support our central hypothesis that Notch signaling in VSMCs provides instructive cues required for proper organization and function of the arterial vasculature. The goal of this proposal is to further study, in a comprehensive manner, the role of Notch signaling in VSMC biology in vitro and in vivo. In Aim 1, studies in mouse embryos harboring Notch signaling-deficient VSMCs will be undertaken to map the temporal-spatial organization of emerging vessels during pre-natal development as a basis for the observed post-natal anatomical abnormalities. Aim 2 will address the functional dynamics of Notch signaling-deficient VSMCs within native vessels by examining vasoreactive responses to physiological and chemical stimuli important for cerebral and peripheral vascular homeostasis. Finally, Aim 3 will examine the molecular basis for altered vessel structure and VSMC function in part through ex vivo and in vitro studies assessing the angiogenic and vessel remodeling contributions of Notch signaling-deficient VSMCs. PUBLIC HEALTH RELEVANCE: Vascular smooth muscle cells (VSMCs) are required for the formation of a competent vascular system. Notch signaling is an important molecular pathway that regulates VSMC function and defects in Notch signaling are genetically linked to human vascular syndromes featuring stroke and congenital cardiovascular abnormalities. This proposal serves to identify at a mechanistic level the precise roles for Notch signaling in VSMCs that confer proper organization and function of the vasculature. The results from these investigations will provide the foundation for novel therapies for the treatment of vascular insufficiencies such as peripheral and cerebral arterial disease.