Ozone Effects on Function of Surfactant Protein Variants

描述(申请人提供)：已发表的工作指出表面活性蛋白A(SP-A)在天然宿主防御中的重要作用。SP-A调节一系列宿主防御过程，暴露在臭氧中会导致SP-A的功能和结构改变。已经鉴定了两个人类基因SP-A1和SP-A2，以及每个SP-A基因的几个遗传变异。体外研究表明，这两个基因和基因特定变体之间存在功能、结构或生化上的差异。在各种肺部疾病中，SP-A水平会发生改变，并且SP-A基因变异与几种肺部疾病的风险有关。我们的中心假设是，SP-A变异体之间的差异解释了环境侮辱导致肺部疾病风险的差异。我们的具体假设是，这两个人类SP-A基因产物在功能上并不等同于它们的宿主防御功能，并且臭氧暴露对这一功能有不同的影响。为了探讨这一特定假设，我们建议研究臭氧对病原体感染的C57BL/6和SP-A-/-小鼠(目标1)的影响，方法包括：a)在细菌感染下存活；b)清除肺部病原体并限制感染的传播；c)细胞因子的产生，体内巨噬细胞的吞噬指数，SP-A的体内氧化状态；以及对野生型和SP-A-/-小鼠巨噬细胞体外宿主防御功能的影响(目标2)。在SP-A-/-背景下建立表达等量人SP-A1或SP-A2基因产物的转基因小鼠系(目标3)。为研究臭氧对SP-A1和SP-A2转基因小鼠品系的影响，进行与Aim 1相似的研究，并研究转基因产物的生化特性(Aim 4)，以及SP-A1和SP-A2转基因小鼠品系巨噬细胞的体外宿主防御功能(Aim 5)。通过拟议的工作，我们将建立一个动物模型来研究人类SP-A变体，我们将在体内确定SP-A在宿主防御中的作用，并评估两种人类SP-A基因产物之间的功能宿主防御差异。所获得的知识可能有助于解释并可能将体外数据与人类基因关联数据联系起来，并为理解SP-A基因复制的价值提供洞察力。

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.