PLAGL2 Expression in Emphysema Patient Lungs

描述(由申请人提供)： 摘要：多形性腺瘤基因类2(PLAGL2)是表面活性蛋白C(SP-C)的反式激活因子。为了研究PLAGL2基因表达对体内SP-C产生的影响，建立了一种肺特异的PLAGL2转基因小鼠模型。在多西环素(Dox)诱导II型和细支气管上皮细胞PLAGL2表达后，转基因小鼠的肺出现了加速的小叶中心型肺气肿。这种表型出现在具有不同PLAGL2基因拷贝的多个小鼠创始人身上，这表明整合位点或转基因拷贝数的贡献很小。在这个PLAGL2转基因小鼠模型中，涉及巨噬细胞、中性粒细胞和CD8淋巴细胞的呼吸道炎症在人类COPD的发展过程中没有出现。雌性小鼠表现出更高的肺气肿发病率，这表明这种小叶中心型肺气肿的小鼠模型可能与最近显示女性慢性阻塞性肺疾病(COPD)患病率增加的数据相似。该小鼠模型的初步特征表明，在诱导的小鼠肺中，PLAGL2和SP-C在远端呼吸道上皮细胞中的表达均上调。这项研究的假设是PLAGL2可能在表面活性物质蛋白动态平衡中发挥作用，能够引发人类小叶中心型肺气肿。这一假设将通过LTRC提供的患者样本进行验证。PLAGL2的表达将通过免疫组织化学(IHC)染色检测来自肺气肿患者、以慢性支气管炎为主的慢性阻塞性肺疾病患者或对照组的组织切片。PLAGL2的相对表达水平将通过激光捕获显微解剖(LCM)技术从肺气肿病变内收集的样本中分离出来的实时PCR分析来评估。对肺气肿基因芯片的传统IHC染色和定量RT-PCR分析得到的评分结果将进行评估，以确定PLAGL2的表达与疾病严重程度的相关性。由于PLAGL2的长期肺特异性表达会导致小鼠小叶中心型肺气肿，而且有数据表明PLAGL2可能直接诱导细胞凋亡，或者由于错误处理的SP-C的过度产生而导致细胞毒性变化，因此PLAGL2在人类COPD患者肺气肿中发挥作用的可能性很大。(摘要结束) 公共卫生相关性： 项目简介：利用动物模型，发现肺细胞中的分子异常与肺泡扩大的结果相关，称为肺气肿。这项研究将使用LTRC收集的人类患者样本来建立该分子作为人类肺气肿发病机制的新机制的概念。

DESCRIPTION (provided by applicant): Abstract: Pleomorphic Adenoma Gene Like-2 (PLAGL2) was identified as a transactivator of surfactant protein C (SP-C). In an attempt to examine the effect of PLAGL2 expression on SP-C production in vivo, an inducible, a lung specific PLAGL2 transgenic mouse model was developed. Lungs from transgenic mice developed an accelerated form of centrilobular emphysema following doxycycline (Dox) induction of PLAGL2 expression in type II and bronchiolar epithelial cells. This phenotype occurred in multiple mouse founders with varying PLAGL2 gene copies, indicating little contribution from integration sites or transgene copy numbers. Airway inflammation involving macrophages, neutrophils, and CD8 lymphocytes that frequently accompanies the development of COPD in humans did not appear in this PLAGL2 transgenic mouse model. Female mice displayed a higher incidence of emphysema, suggesting that this mouse model of centrilobular emphysema might mimic recent data demonstrating an increased prevalence of chronic obstructive pulmonary disease (COPD) among women. The initial characterization of this mouse model demonstrated that both PLAGL2 and SP-C expression were upregulated in distal airway epithelial cells in the induced mouse lung. The hypothesis of this study is that PLAGL2, which may play a role in surfactant protein homeostasis, is capable of initiating centrilobular emphysema in humans. This hypothesis will be tested with the supply of patient samples from LTRC. PLAGL2 expression will be examined on immunohistochemistry (IHC) staining of tissue sections from patients with histologic evidence of emphysema, COPD with predominantly chronic bronchitis, or controls. Relative levels of PLAGL2 expression will be evaluated using real-time PCR analysis of transcripts isolated from samples collected within the emphysema lesion by laser capture microdissection (LCM) technique. Scoring results obtained from both traditional IHC staining and the quantitative RT-PCR analysis of cDNA array of emphysema will be assessed to determine the correlation of PLAGL2 expression with disease severity. Given that long term lung specific expression of PLAGL2 results in centrilobular emphysema in mice, and data suggesting that PLAGL2 may either directly induce apoptosis or cause cytotoxic changes from overproduction of misprocessed SP-C, the probability that PLAGL2 plays a role in emphysema in humans with COPD is substantial. (End of Abstract) PUBLIC HEALTH RELEVANCE: Project Narrative: Using an animal model, a molecular abnormality in lung cells has been found correlated with the outcome of airspace enlargement, known as emphysema. This research will use the LTRC collected human patient samples to establish the concept of this molecule as a novel mechanism of pathogenesis of emphysema in humans.