Mechanisms of endothelial regeneration and resolution of lung vascular injury

项目摘要。内皮屏障完整性丧失是急性呼吸窘迫发病机制的核心 综合征(ARDS)是一种严重的肺部疾病，与脓毒症和创伤有关。因此，动态平衡补给 为了有效地形成稳定的内皮屏障并防止长时间的内皮细胞损伤，损伤后内皮细胞的活性是必需的 肺血管损伤，但这些“修复性内皮细胞(ECs)”的身份和来源尚不清楚。 鉴于这一发现，内皮细胞可以在组织损伤后转化为成纤维细胞样细胞(FLC)，并迫使 ETS家族转录因子(如ETV2)的表达将FLC重新编程为ECs，这是一个基本的 悬而未决的问题是，从“修复性的”EC谱系转变为非修复性的FLC谱系 损害内皮细胞再生，从而从肺血管损伤中恢复。PTEN(磷酸酶和 Tensin Homolog)是一种众所周知的肿瘤抑制因子，并调节血管形成的关键特征，如 内皮细胞迁移和增殖。我们的初步数据显示，欧共体特有的有条件删除 PTEN显著减少肺内皮细胞再生，而Flc增加，并使这些小鼠形成肺 自发的浮肿。进一步的实验表明，PTEN定位于内皮细胞的胞核并维持 内皮转录因子ETS相关基因(ERG)的表达。基于这些耐人寻味 初步数据，并使用一系列强大的方法，如新的遗传小鼠模型(可诱导 用于谱系追踪的双报告EC-PTEN和EC-ERG缺失小鼠)、RNAseq和肺血管测量 通透性我们将研究PTEN诱导的ERG通路是EC的关键决定因素的假设 肺水平衡的谱系和分解。我们的具体目标是：#1：调查假设 EC表达的PTEN以成纤维样细胞为代价促进内皮细胞再生 从而维持肺血管屏障；#2：确定(A)内皮细胞转录的作用 ERG因子，作为PTEN的效应因子和EC谱系的关键决定因素，以及(B)鉴定ERG丰富 通过内皮谱系追踪的内皮细胞作为其激活的内在修复性内皮细胞 促进肺血管再生，恢复肺液平衡。凭借这些全面的 研究，我们将首次确定PTEN-ERG级联在维持修复性EC中的作用 在血统和解决炎症性肺血管损伤方面。我们期待我们的研究为我们的研究奠定一个新的概念 利用PTEN作为治疗的关键靶点开发新的治疗方法的框架 急性呼吸窘迫综合征。

Project Summary. Loss of endothelial barrier integrity is central to pathogenesis of acute respiratory distress syndrome (ARDS), a severe lung disease, associated with sepsis and trauma. Thus, homeostatic replenishment of ECs after injury is required for the efficient formation of a stable endothelial barrier and to prevent long-lasting lung vascular injury but the identity and source of these “reparative endothelial cells (ECs)” remains unclear. Given the findings that ECs can convert into fibroblast-like cells (FLC) upon tissue injury and that forced expression of the ETS family of transcription factors (e.g., ETV2) reprogram FLC into ECs, a fundamental unanswered question is whether a shift from the “reparative” EC lineage into a non-reparative FLC lineage impairs endothelial regeneration and thereby recovery from lung vascular injury. PTEN (Phosphatase and TENsin homolog) is a well-known tumor suppressor and regulates key features of vascularization such as endothelial migration and proliferation. Our Preliminary Data, showed that EC-specific conditional deletion of PTEN markedly decreased lung EC regeneration while FLCs were increased and these mice developed lung edema spontaneously. Further experiments showed that PTEN localized to the nucleus of ECs and maintained the expression of endothelial transcription factor, Ets-Related Gene (ERG). Based on these intriguing Preliminary Data, and using a range of powerful approaches such as novel genetic mouse models (inducible dual-reporter EC-PTEN and EC-ERG null mice for lineage tracing), RNAseq and measurements of lung vascular permeability we will investigate the hypothesis that PTEN-induced ERG pathway is a key determinant of the EC lineage and resolution of lung-fluid balance. Our Specific Aims are: #1: to investigate the hypothesis that EC-expressed PTEN drives endothelial cell regeneration at the expense of fibroblast-like cells and thereby maintains the lung vascular barrier; #2: to determine (a) the role of the endothelial transcription factor, ERG, as an effector of PTEN and a key determinant of EC lineage, and (b) to identify ERG enriched endothelial cells through endothelial lineage tracing as intrinsic reparative ECs whose activation promotes lung vascular regeneration and restoration of lung fluid balance. With these comprehensive studies, we will identify for the first time the role of the PTEN-ERG cascade in maintaining the reparative EC lineage and in resolving inflammatory lung vascular injury. We expect our studies to lay a new conceptual framework for the development of novel therapeutic approaches exploiting PTEN as a key target for the treatment of ARDS.