Mechanisms of MCP-1 in lung contusion with and without gastric aspiration

描述（由申请人提供）：肺挫伤是机动车事故和爆炸创伤受害者常见的伤害。它也是ALI、ARDS和呼吸机相关性肺炎发展的独立危险因素。根据我们对动物的初步研究，它在临床上经常与创伤时的胃误吸有关，可进一步增加肺损伤的严重程度和ALI/ARDS的风险。本研究主要研究孤立性肺挫伤和胃误吸性肺挫伤的小鼠模型。重点是对mcp -1和MCP-5在这些损伤的单独和联合发病机制中的保护作用的机制理解，包括该趋化因子在促进肺泡巨噬细胞的募集和激活以及随后凋亡的中性粒细胞的吞噬中的特定作用。该基金有三个具体目标。目的1研究缺乏MCP-1、MCP-5或受体蛋白CCR2的敲除小鼠以及给予这些分子抗体的野生型小鼠肺挫伤中的肺损伤和先天性肺部炎症。这些在体内的研究被补充了一些实验，在这些实验中，分离的肺泡巨噬细胞在体外被检测表型参数、吞噬潜能和细胞特异性炎症介质谱。此外，通过使用骨髓来源的嵌合体来研究肺挫伤中主要负责MCP-1产生的细胞的来源。此外，研究人员还研究了TLR9与细胞内接头蛋白MyD 88在肺泡巨噬细胞损伤识别以及随后MCP-1的激活和细化中的重要性。Aim 2涉及与Aim 1类似的研究，以确定MCP-1和MCP-5在肺挫伤胃误吸联合损伤模型中的详细活性和作用机制。趋化因子活性与肺泡巨噬细胞活性的确切机制以及TLR9在MCP-1或MCP-5产生中的作用与目的1相似。目的3研究在肺挫伤和胃吸伤肺挫伤后，通过直接滴注和电穿孔促进含有MCP-1的DNA质粒的基因传递给MCP-1（-/-）和野生型小鼠，将外源性MCP-1传递到肺部的影响。后两项研究扩展了目的1和目的2，进一步证明了MCP-1在伴或不伴胃误吸的肺挫伤中的功能意义，同时研究了基于该趋化因子或相关药物肺递送的潜在未来治疗的疗效。

DESCRIPTION (provided by applicant): Lung contusion is a common injury sustained by victims of motor vehicular accidents and blast trauma. It is also an independent risk factor for the development of ALI, ARDS and ventilator associated pneumonia. It is frequently associated clinically with gastric aspiration at the time of trauma that can further increase the severity of lung injury and the risk of ALI/ARDS based on our preliminary studies in animals. The current proposal studies murine models of both isolated lung contusion and lung contusion with gastric aspiration. Emphasis is on mechanistic understanding of the protective roles of MCP-1and MCP-5 in the pathogenesis of these injuries alone and in combination, including specific effects of this chemokine in facilitating the recruitment and activation of alveolar macrophages and the subsequent phagocytosis of apoptotic neutrophils. The grant has three Specific Aims. Aim 1 investigates lung injury and innate pulmonary inflammation in lung contusion in knockout mice lacking MCP-1, MCP-5 or the receptor protein CCR2, as well as in wild type mice given antibodies against these molecules. These in vivo studies are complemented by added experiments where isolated alveolar macrophages are examined ex vivo for phenotypic parameters, phagocytic potential, and cell-specific inflammatory mediator profile. Additionally, an investigation of origin of cells primarily responsible for the production of MCP-1 in lung contusion through the use of bone marrow-derived chimeras is proposed. In addition, the importance of TLR9 with the intracellular adaptor protein MyD 88 as an intermediate in the recognition of injury and the subsequent activation and elaboration of MCP-1 from alveolar macrophages is investigated. Aim 2 involves analogous studies to those in Aim 1 to define the detailed activities and mechanisms of action of MCP-1 and MCP-5 in the combined injury model of lung contusion with gastric aspiration. The precise mechanisms of activity of chemokines with alveolar macrophage activity and role of TLR9 in the production of MCP-1 or MCP-5 are similar to aim 1. Aim 3 examines the effects of delivering exogenous MCP-1 to the lungs via direct instillation and by electroporation-facilitated gene delivery of DNA plasmids containing MCP-1 to MCP-1 (-/-) and wild type mice following lung contusion and lung contusion with gastric aspiration. These latter studies extend Aim 1 and 2 to further document the functional significance of MCP-1 in lung contusion with and without gastric aspiration, while at the same time investigating the efficacy of potential future therapies based on the pulmonary delivery of this chemokine or related agents. PUBLIC HEALTH RELEVANCE: This grant seeks to improve understanding about mechanisms contributing to lung contusion and gastric aspiration, two important human pulmonary diseases (lung injuries) that frequently occur in conjunction with blunt chest trauma. Research in the proposal studies the behavior of specific substances in the pulmonary inflammatory response in these diseases, particularly the chemokines MCP-1 and MCP-5 that affect the activity and recruitment of important inflammatory cells such as macrophages. The grant not only studies mechanisms by which early increases in MCP-1 and MCP-5 may aid the timely resolution of acute inflammatory injury during lung contusion with or without gastric aspiration, but also investigates the effects of related pharmacologic and gene delivery approaches to lay the groundwork for possible future chemokine- based drug or gene therapies for these important lung diseases.