Ozone Effects on Function of Surfactant Protein Variants

描述（由申请人提供）：已发表的工作指出表面活性剂蛋白A （SP-A）在先天宿主防御中的重要作用。SP-A调节许多宿主防御过程，暴露于臭氧导致SP-A的功能和结构改变。两个人类基因，SP-A1和SP-A2，以及每个SP-A基因的几个遗传变异已经被表征。体外研究显示两种基因和基因特异性变异之间的功能、结构或生化差异。SP-A水平在多种肺部疾病中发生改变，SP-A基因变异与几种肺部疾病的风险相关。我们的中心假设是SP-A变体之间的差异解释了对环境损害的肺部疾病风险的差异。我们的具体假设是，两种人类SP-A基因产物在宿主防御功能方面功能不同，臭氧暴露对该功能有不同的影响。为了验证这一假设，我们提出通过评估臭氧对病原体感染的C57BL/6和SP-A-/-小鼠（目的1）的影响：a)细菌感染后的存活率；B)清除肺部病原体和限制感染传播的能力；c)细胞因子产量、巨噬细胞体内吞噬指数、SP-A体内氧化状态；以及野生型和SP-A-/-小鼠巨噬细胞的离体宿主防御功能（Aim 2）。在SP-A-/-背景下产生表达等量人SP-A1或SP-A2基因产物的转基因小鼠系（目标3）。研究臭氧对SP-A1和SP-A2转基因小鼠系的影响，通过与Aim 1类似的研究，研究转基因产物的生化特性（Aim 4），以及SP-A1和SP-A2小鼠系巨噬细胞的体外宿主防御功能（Aim 5）。通过提出的工作，我们将建立一个动物模型来研究人类SP-A变异，我们将确定，在体内，并响应臭氧暴露，SP-A在宿主防御中的作用，并评估两种人类SP-A基因产物在宿主防御功能上的差异。所获得的知识可能有助于解释或可能将体外数据与人类遗传关联数据联系起来，并为理解SP-A基因复制的价值提供见解。

DESCRIPTION (provided by applicant): Published work points to an important role of surfactant protein A (SP-A) in innate host defense. SP-A modulates a number of host defense processes and exposure to ozone results in functional and structural alterations of SP-A. Two human genes, SP-A1 and SP-A2, and several genetic variants for each SP-A gene have been characterized. In vitro studies show functional, structural, or biochemical differences between the two genes and the gene-specific variants. SP-A levels are altered in a variety of lung diseases, and SP-A genetic variants are associated with risk for several pulmonary diseases. Our central hypothesis is that differences among SP-A variants account for differences in risk to lung disease in response to environmental insults. Our specific hypothesis is that the two human SP-A gene products are not functionally equivalent with regards to their host defense function, and that ozone exposure has a differential impact on this function. To investigate the specific hypothesis, we propose to study the effect of ozone, on pathogen-infected C57BL/6 and SP-A-/- mice (Aim 1) by assessing: a) survival with bacterial infection; b) ability to clear pathogens from their lungs and limit dissemination of infection; c) cytokine production, the in vivo phagocytic index of macrophages, and the in vivo oxidation status of SP-A; as well as, on the ex vivo host defense function of macrophages from wild type and SP-A-/- mice (Aim 2). To generate transgenic mouse lines on the SP-A-/- background that express equivalent levels of human SP-A1 or SP-A2 gene products (Aim 3). To study the impact of ozone on the SP-A1 and SP-A2 transgenic mouse lines by carrying out studies similar to those described for Aim 1 and by studying biochemical characteristics of the transgene products (Aim 4), and the ex vivo host defense function of macrophages from the SP-A1 and SP-A2 mouse lines (Aim 5). Through the proposed work we will generate an animal model to study human SP-A variants, and we will determine, in vivo, and in response to ozone exposure, the role of SP-A in host defense and assess functional host defense differences between the two human SP-A gene products. Knowledge gained may help explain and perhaps link the in vitro data with the human genetic association data, and provide insight in the understanding of the value of the SP-A gene duplication.