Mitochondrial Dysfunction in the Endothelium as a Mediator of Inflammatory Injury

摘要 研究表明，内皮细胞通过调节细胞内流和表型，在宿主防御中起着关键作用 免疫细胞。项目3的重点是描绘线粒体功能障碍和线粒体自噬在内皮细胞凋亡中的作用。 细胞在调节肺血管稳态和损伤时宿主防御中的作用。拟议的研究将确定 EC中线粒体损伤的机制以及适应性线粒体自噬如何激活代偿性线粒体 生物起源项目3还将研究线粒体自噬和线粒体肽的释放如何影响中性粒细胞 在炎症性肺损伤期间。本提案将解决的基本问题包括： TNFα诱导线粒体损伤和线粒体自噬的机制是什么？我们能用生物传感器来检测线粒体吗 在体外和体内，以确定关键阶段的线粒体自噬和补偿线粒体生物发生？如何 内皮细胞线粒体自噬影响内皮细胞代谢的恢复和内皮细胞的再生？如何 内皮细胞线粒体自噬影响中性粒细胞信号传导、炎性损伤和宿主防御。项目3将测试 肺内皮细胞线粒体自噬是内皮细胞稳态的中心调节因子， 免疫反应这将在两个目标中解决。目的1：确定内皮细胞线粒体自噬的作用， 代偿性线粒体生物发生以恢复内皮再生和稳态， 炎性肺损伤在这里，我们将测试炎症诱导线粒体损伤的假设， 肺内皮细胞中的适应性线粒体自噬以协调内皮细胞再生和稳态。此外，委员会认为， 我们认为恢复内稳态的中心机制是通过线粒体的代偿性生物合成。 我们使用内皮细胞线粒体自噬的活体双光子成像（使用核心D），并使用EC-2000进行体内研究。 线粒体自噬介体PINK 1、线粒体生物发生转录因子PGC 1 α的特异性遗传缺失 和TFAM，以及线粒体磷酸酶PGAM 5（将线粒体自噬后信号传递到细胞核） 在人肺内皮细胞中进行了机械驱动的体外研究。这些研究将与EC的分析相结合。 代谢、线粒体生物发生和EC再生。目的2：确定内皮细胞线粒体自噬的作用 在炎症损伤期间激活肺宿主防御功能。在这里，我们将测试的假设， EC-线粒体自噬增加跨内皮中性粒细胞流入，从而通过分泌 甲酰化肽和甲酰肽受体的活化。我们将使用EC特异性PINK 1的遗传模型， 在不同的炎症性肺损伤模型（LPS和肺炎假单胞菌）中缺失，并分析EC 表观遗传和转录调控（核心B）所造成的线粒体自噬，并解决这些如何有助于 EC和EC PINK 1下游中性粒细胞的宿主防御功能。我们还将评估EC-PINK 1如何调节 嗜酸性粒细胞诱导的肺损伤和N-甲酰化线粒体肽的产生。我们还将确定 肺EC线粒体自噬对中性粒细胞迁移和细菌吞噬作用的影响（核心D），并研究 在嗜中性粒细胞中线粒体甲酰基肽下游的信号传导途径（具有核心C）。

ABSTRACT Studies have shown that the endothelium plays a critical role in host defense by regulating the influx and phenotype of immune cells. Project 3 focuses on delineating the role of mitochondrial dysfunction and mitophagy in endothelial cells in regulating lung vascular homeostasis and host-defense during injury. The proposed studies will identify mechanisms of mitochondrial injury in ECs as well as how adaptive mitophagy activates compensatory mitochondrial biogenesis. Project 3 will also examine how mitophagy and the release of mitochondrial peptides impact neutrophils during inflammatory lung injury. The fundamental questions that will be addressed by this proposal include: What are the mechanisms of TNFα induced mitochondrial injury and mitophagy? Can we use biosensors for mitochondria in vitro and in vivo to define key phases of mitophagy and compensatory mitochondrial biogenesis? How does endothelial mitophagy affect restoration of endothelial metabolism and endothelial regeneration? How does endothelial mitophagy impact neutrophil signaling, inflammatory injury and host defense. Project 3 will test the overall hypothesis that lung endothelial mitophagy is a central regulator of endothelial homeostasis and the innate immune response. This will be addressed in two Aims. Aim 1: Determine the role of endothelial mitophagy and compensatory mitochondrial biogenesis to restore endothelial regeneration and homeostasis during inflammatory lung injury. Here we will test the hypothesis that inflammation induces mitochondrial injury and adaptive mitophagy in the lung endothelium to orchestrate endothelial regeneration and homeostasis. Furthermore, we posit that the central mechanism of restoring homeostasis is through the compensatory mitochondrial biogenesis. We use intravital two photon imaging of endothelial mitophagy (with Core D) and perform in vivo studies using EC- specific genetic deletion of the mitophagy mediator PINK1, the mitochondrial biogenesis transcription factors PGC1α and TFAM, and the mitochondrial phosphatase PGAM5 (which transfers post-mitophagy signaling to the nucleus) with mechanistically driven in vitro studies in human lung ECs. These studies will be coupled to analysis of EC metabolism, mitochondrial biogenesis, and EC regeneration. Aim 2: Determine the role of endothelial mitophagy in activating the lung host-defense function during inflammatory injury. Here we will test the hypothesis that EC-mitophagy increases transendothelial neutrophil influx and thereby bacterial killing through secretion of formylated peptides and activation of formyl peptide receptors. We will use genetic models of EC-specific PINK1 deletion in distinct models of inflammatory lung injury (LPS and Pseudomonas pneumonia) and analyze EC epigenetic and transcriptomic regulation (with Core B) wrought by mitophagy and address how these contribute to host-defense function of EC and neutrophils downstream of EC PINK1. We will also assess how EC-PINK1 regulates neutrophil-induced lung injury and generation of N-formylated mitochondrial peptides. We will also determine the effects of lung EC mitophagy on neutrophil transmigration and bacterial phagocytosis (with Core D) and study the signaling pathways (with Core C) downstream of mitochondrial formyl peptides in neutrophils.