Role of cytoglobin in promoting smooth muscle cell survival during maladaptive vascular remodeling

我们对动脉粥样硬化和非动脉粥样硬化性心脏病血管重构调控机制的认识 动脉粥样硬化性血管病变仍然是不够的。这代表着重要的速率限制步骤 改进或设计新的治疗干预措施，在动脉粥样硬化形成期间或在 晚期动脉粥样硬化病变。在心血管系统中，包括血红蛋白和 肌红蛋白被认为只负责运输和储存分子氧，并调节一氧化氮。 生物利用度。然而，最近的证据表明，这种模式并不是完全的和哺乳动物的。 细胞球蛋白(Cygb)等珠蛋白在血管重塑中可能具有重要作用 不依赖于氧气的储存和运输。我们发现，CygB在 啮齿动物和人类血管的中层平滑肌细胞。我们已经取得了很好的初步结果 表明在体内和体外，CygB抑制血管损伤中的细胞凋亡，我们已经产生了 一种允许组织特异性缺失CygB的小鼠品系。这项提案的目标是测试 平滑肌细胞色素B结合新型抗细胞凋亡药物和一氧化氮的一般假设 对抑制动脉粥样硬化斑块发病有良好效果的消食功能。在……里面 目的1，我们将检验一种假说，即平滑肌特异性条件性敲除细胞色素B基因将 增加了平滑肌细胞的凋亡率，损害了平滑肌细胞的流失， 斑块稳定性指数。我们将使用新的遗传编码细胞谱系追踪方法在 小鼠动脉粥样硬化模型联合靶向条件性缺失血管内皮细胞色素B。 在目标2中，我们将确定一氧化氮信号在细胞色素B功能中的作用。 血管系统和晚期动脉粥样硬化斑块中的功能和代谢组学 特征结合一氧化氮合酶(NOS)和CygB基因缺失。在目标3中，我们 将决定细胞色素B在细胞凋亡中的作用机制。为此，我们将确立 细胞色素B通过氧化还原和基因表达调控细胞凋亡下游效应因子caspase-3 调节对其激活的抑制。最后，我们将检验CyGB作为NO和AND的假设 O2传感器用于调节下游信号。总的来说，这项工作将通过对人类的研究来指导 动脉粥样硬化斑块样本来自无症状和有症状的患者。结果是 从拟议的实验中衍生出来的将挑战目前与哺乳动物珠蛋白相关的教条 起简单的氧气运输和一氧化氮处理系统的作用。最终，我们希望 在血管系统中描绘新的有利于生存的通路，这些通路可以被操纵以减轻 通过联合调控细胞凋亡和一氧化氮生物效应来实现不适当的血管重构 可用性。

Our knowledge of mechanisms regulating vascular remodeling in atherosclerotic and non- atherosclerotic vasculopathies is still inadequate. This represents an important rate-limiting step to improve or design new therapeutic interventions that may prove beneficial during atherogenesis or in advanced atherosclerotic lesions. In the cardiovascular system, globins including hemoglobin and myoglobin are thought exclusively to transport and store molecular oxygen and regulate nitric oxide bioavailability. However, recent evidence suggests that this model is not complete and mammalian globins such as cytoglobin (CYGB) might have important functions in vascular remodeling that are independent of oxygen storage and transport. We discovered that CYGB is abundantly expressed in medial smooth muscle cells of rodent and human vessels. We have obtained strong preliminary results showing that CYGB inhibits apoptosis during vascular injury in vivo and in vitro and we have generated a floxed mouse line allowing for tissue specific deletion of CYGB. The goal of this proposal is to test the general hypothesis that smooth muscle CYGB combines novel anti-apoptotic and nitric oxide consuming functions that have favorable effects in inhibiting atherosclerotic plaque pathogenesis. In Aim 1, we will test the hypothesis that smooth muscle specific conditional knockdown of CYGB will increase smooth muscle cell apoptosis, with a detrimental loss of smooth muscle cells, and a decrease in indices of plaque stability. We will use novel genetically encoded cell lineage tracing approaches in a mouse model of atherosclerosis combined with targeted conditional deletion of smooth muscle CYGB. In Aim 2, we will establish the contribution of nitric oxide signaling to the function of CYGB in the vasculature and in advanced atherosclerotic plaques through functional and metabolomics characterization combined with nitric oxide synthase (NOS) and CYGB genetic deletion. In Aim 3, we will determine the mechanism of action of CYGB in apoptosis. To this end, we will establish the role of CYGB in regulating the downstream effector of apoptosis caspase-3 through redox- and gene- regulated inhibition of its activation. Finally, we will test the hypothesis that CYGB serves as an NO and O2 sensor to regulate downstream signals. Overall, this work will be guided through studies of human atherosclerotic plaque samples derived from asymptomatic and symptomatic patients. The results derived from the proposed experiments will challenge the current dogma related to mammalian globin functions as simply oxygen transport and nitric oxide handling systems. Ultimately, we hope to delineate novel pro-survival pathways in the vasculature that could be manipulated to mitigate inappropriate vascular remodeling through combined regulation of apoptosis and nitric oxide bio- availability.