Mitochondrial network remodeling and the development of the hyper-proliferative and antiapoptotic endothelial phenotype.

项目摘要 肺血管疾病是常见的婴儿和儿童发病率显著增加的原因 导致肺血流量(PBF)和压力增加的先天性心脏缺陷。缺少这样一个人 限制内皮功能障碍和血管病变的共同病理生理特征的有效治疗 改建。我们最近的研究表明，代谢重新编程和线粒体功能障碍， 由机械应激介导，是这些儿童血管损伤的核心调节途径。 此外，我们最近发现了一种高增殖、抗凋亡的内皮细胞表型。 在我们的分流羔羊模型中，PBF和压力增加参与了血管生成反应并导致 肺小动脉数量增多。我们的数据表明，这种内皮细胞表型与 Survivin(一种抗凋亡蛋白)表达增加，线粒体分裂和增加 自噬/有丝分裂。这些过程与NO信号的丢失有关。我们体内NO信号的减少 分流羔羊模型的发生，至少部分是通过减少ATP介导的HSP90的激活来实现的。大块头 与过度增殖相关的代谢要求需要大量消耗ATP。基于 这些数据我们的总体假设是，维持超增殖、抗衰老所需的ATP消耗 细胞凋亡、血管内皮细胞表型与PBF和压力升高有关，在这种丧失中起着重要作用 通过减弱HSP90的活性来抑制NO信号。我们的数据表明RhoA/ROCK信号是 这些小路。我们实验室的研究表明，连接S1PR3受体，诱导Rho GTP酶信号转导 和细胞骨架重塑。有趣的是，S1PR1受体对机械刺激具有保护作用 应激，在我们的分流羔羊模型的肺中显著下调，而S1PR3受体的表达 增加了。我们假设机械应力介导了S1PR3受体-RhoA/ROCK的激活 AXIS负责线粒体的分裂、自噬/有丝分裂和凋亡，它们协同作用产生 高增殖、抗凋亡的内皮细胞表型和NO信号的丢失。三个具体目标 (SA)被提出来检验这一假设。在目标1中，我们将定义线粒体分裂在 发展一种高增殖的内皮细胞表型，并确定这如何调节NO信号。在……里面 目的2，我们将表征自噬/有丝分裂吞噬在条件下NO信号丢失中所起的作用 并研究抗凋亡因子Survivin(Birc5)在其中所起的作用。在……里面 目的3，我们将确定靶向线粒体分裂和自噬是否是潜在的治疗靶点。 在我们的临床前分流羔羊模型中。随着这项研究的完成，我们将大幅增加 线粒体网络重塑和自噬/有丝分裂吞噬在脑出血中的作用 肺血管疾病的发病机制与PBF和压力增加有关，同时强调 新型治疗干预措施的应用。

Project Summary Pulmonary vascular disease is responsible for significant morbidity in infants and children with common congenital heart defects that result in increased pulmonary blood flow (PBF) and pressure. There is a lack of effective therapies to limit the shared pathophysiologic features of endothelial dysfunction and vascular remodeling. Our recent studies have demonstrated that metabolic reprogramming and mitochondrial dysfunction, mediated by mechanical stress, is a core regulatory pathway underlying the vascular injury in these children. Further, we have recently identified the presence of a hyper-proliferative, anti-apoptotic endothelial phenotype in our Shunt lamb model of increased PBF and pressure that is involved in an angiogenic response and results in an increase in pulmonary arteriole number. Our data indicate that this endothelial phenotype is associated with increased expression of survivin (an anti-apoptotic protein), mitochondrial fission and increased autophagy/mitophagy. These processes are linked to a loss of NO signaling. The decreased NO signaling in our Shunt lamb model occurs, at least in part, through a decrease in ATP-mediated hsp90 activation. The massive metabolic requirement associated with hyper-proliferation requires a significant consumption of ATP. Based on these data our overall hypothesis is that the ATP consumption required to maintain the hyper- proliferative, anti- apoptotic, endothelial phenotype associated with increased PBF and pressure plays a significant role in the loss of NO signaling by attenuating hsp90 activity. Our data implicate RhoA/ROCK signaling as a master-regulator of these pathways. Studies in our lab have shown that ligation of S1PR3 receptor, induces Rho GTPase signaling and cytoskeletal remodeling. Interestingly, S1PR1 receptor, which exerts a protective effect against mechanical stress, is significantly downregulated in the lungs of our Shunt lamb model, while S1PR3 receptor expression is increased. We hypothesize that a mechanical stress mediated activation of an S1PR3 receptor-RhoA/ROCK axis is responsible for the mitochondrial fission, autophagy/mitophagy, and apoptosis that synergize to produce the hyper-proliferative, anti-apoptotic endothelial phenotype and the loss of NO signaling. Three Specific Aims (SAs) are proposed to test this hypothesis. In Aim 1, we will define the role of mitochondrial fission in the development of a hyper-proliferative endothelial phenotype and determine how this modulates NO signaling. In Aim 2, we will characterize the role played by autophagy/mitophagy in the loss of NO signaling under conditions of increased PBF and pressure and investigate the role played by the anti- apoptotic factor, survivin (Birc5). In Aim 3, we will determine whether targeting mitochondrial fission and autophagy are potential therapeutic targets in our pre-clinical Shunt lamb model. With the completion of this study, we will significantly increase our understanding of the role played by mitochondrial network remodeling and autophagy/mitophagy in the pathogenesis of pulmonary vascular disease associated with increased PBF and pressure while highlighting the application of novel therapeutic interventions.