Prevention of Endothelial Injury by Toll-like Receptor 4 Modulators

 个人描述(申请人提供)：我是范德比尔特大学医学院儿科重症监护科的助理教授。作为一名儿科重症医生，我经常会遇到与疾病相关的炎症，尽管医学领域取得了进展，但仍会导致显著的发病率和死亡率。我一直对免疫、炎症和血管生物学有浓厚的兴趣。我之前的工作研究了脂多糖(LPS)诱导的血栓形成的血小板依赖机制。在此期间，我利用活体显微镜和内毒素血症动物模型中的血小板聚集计量学，重点研究了Toll样受体4(TLR4)依赖的微血管血栓形成机制。这一奖项将使我能够继续探索炎症的机制，特别是感染过程中内皮损伤的调节。同样重要的是，在这个奖项期间进行的活动将通过结构化的课程和指导监督来帮助我实现成功的研究独立，从而促进我作为一名内科科学家的职业发展。医院获得性感染是危重患者发病率和死亡率的主要原因，其中危重烧伤患者尤其脆弱。严重感染会导致严重的内皮功能障碍和损伤，这是一氧化氮和活性氧产生变化的结果。然而，目前尚不清楚感染是如何在内皮细胞中具体调节这些途径的。此外，目前还没有可用的预防策略来调节感染过程中的内皮损伤。在这项提案中，我们将重点关注感染过程中依赖内皮型一氧化氮合酶(ENOS)的内皮功能的变化，并应用TLR4指导的调节剂单磷脂a(Mpla)。目的1：建立内皮细胞TLR4信号改变eNOS功能的机制。这些实验的重点将是确定TLR4激活诱导eNOS功能障碍以及与之相关的一氧化氮和活性氧生成变化的机制。目的2：探讨聚乳酸对内皮细胞炎症调节作用的机制。我们将确定在微生物攻击之前Mpla处理对人内皮细胞产生保护作用的机制。目的3：明确烧伤创面感染时，Mpla预防内皮功能障碍的能力。在这些研究中，我们将在一个临床相关的烧伤创面感染动物模型中研究MLA如何预防全身性内皮依赖性血管功能障碍。本研究的目的是了解导致内皮功能障碍的细胞内机制，并确定感染诱导的eNOS依赖信号的作用。如果对内皮的负面影响能够被Mpla调节，这一发现将具有直接的治疗潜力。烧伤合并获得性感染的炎症反应是独一无二的，因为这些脆弱的患者通常在感染变得明显之前就得到了医疗关注。因此，它是高度顺从的预防性的 心理治疗。

 DESCRIPTION (provided by applicant): I am an Assistant Professor in the Division of Pediatric Critical Care at Vanderbilt University School of Medicine. As a Pediatric Intensivist, I encounter patients on a regular basis that suffer from disease-related inflammation, which despite advances in the medical field, still lead to significant morbidity and mortality. I have always had a strong interest in immunity, inflammation and vascular biology. My previous work examined platelet-dependent mechanisms of lipopolysaccharide (LPS)-induced thrombosis. During that time, I focused on toll-like receptor 4 (TLR4)-dependent mechanisms of microvascular thrombosis using intravital microscopy and platelet aggregometry in animal models of endotoxemia. This award will allow me to continue to explore mechanisms of inflammation, specifically the modulation of endothelial injury during infections. Equally important, the activities pursued during this award will enhance my career development as a physician-scientist through a structured curriculum and mentored oversight to help me achieve successful research independence. Hospital-acquired infections are a leading cause of morbidity and mortality in critically-ill patients, among which critically-injured burn patients ar particularly vulnerable. Severe infections cause significant endothelial dysfunction and injury that is a consequence of alterations within nitric oxide and reactive oxygen species generation. However, it is unclear how infections specifically modulate these pathways in endothelial cells. Furthermore, there are no current preventative strategies available to modulate endothelial injury during infection. In this proposal, we will focus on endothelial nitric oxide synthase (eNOS)- dependent changes in endothelial function during infection and apply a TLR4-directed modulator, monophosphoryl lipid a (MPLA). Aim 1: Establish the mechanism by which endothelial TLR4 signaling alters eNOS function. The focus of these experiments will be to define the mechanisms by which eNOS dysfunction and associated alterations in nitric oxide and reactive oxygen species generation are induced by TLR4 activation. Aim 2: Determine the mechanism of MPLA-induced inflammatory modulation in endothelial cells. We will determine the mechanisms by which MPLA treatment prior to microbial challenge induces a protective effect on human endothelial cells. Aim 3: Define the ability of MPLA to prevent endothelial dysfunction in the setting of a burn-wound infection. In these studies, we will examine how MPLA prevents systemic endothelial- dependent vascular dysfunction in a clinically relevant animal model of burn-wound infection. The goal of this study is to understand the intracellular mechanisms leading to endothelial dysfunction and define the role of eNOS-dependent signals induced by infection. If the negative effects on the endothelium can be modulated with MPLA, this finding will have immediate therapeutic potential. The inflammatory response of burn injury with acquired infection is unique because these vulnerable patients typically come to medical attention before the infection becomes significant. It is therefore highly amenable to preventative therapy.