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，并且暴露于臭氧导致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体已被表征。体外研究表明，这两个基因和基因特异性变体之间存在功能、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遗传变异与几种肺部疾病的风险相关。我们的中心假设是SP-A变异体之间的差异解释了对环境损伤的肺部疾病风险的差异。我们的具体假设是，这两种人类SP-A基因产物在其宿主防御功能方面功能不等同，臭氧暴露对这种功能有不同的影响。为了研究特定的假设，我们建议研究臭氧对病原体感染的C57 BL/6和SP-A-/-小鼠（目的1）的影响，通过评估：a）细菌感染的存活率; B）从肺部清除病原体和限制感染传播的能力; c）细胞因子产生，巨噬细胞的体内吞噬指数和SP-A的体内氧化状态;以及对来自野生型和SP-A-/-小鼠的巨噬细胞的离体宿主防御功能的影响（目的2）。在SP-A-/-背景下生成表达同等水平人SP-A1或SP-A2基因产物的转基因小鼠品系（目的3）。通过进行与目标1所述研究相似的研究，并通过研究转基因产物的生物化学特性（目标4）以及SP-A1和SP-A2小鼠系巨噬细胞的离体宿主防御功能（目标5），研究臭氧对SP-A1和SP-A2转基因小鼠系的影响。通过拟议的工作，我们将产生一个动物模型来研究人类SP-A变异体，我们将确定，在体内，并在臭氧暴露，SP-A在宿主防御中的作用，并评估两个人类SP-A基因产物之间的功能性宿主防御差异。所获得的知识可能有助于解释体外数据，并可能将其与人类遗传关联数据联系起来，并为理解SP-A基因重复的价值提供见解。

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.