PM Induced Altered Regulation of G1 Cyclins in AEC

描述(由申请人提供)： 环境空气污染颗粒物(PM)与包括肺癌在内的急性和慢性心肺损伤所致的发病率和死亡率的增加有关。最近的研究表明，PM通过引起DNA损伤和细胞凋亡而对肺泡上皮细胞(AEC)产生遗传毒性。血管内皮细胞损伤和修复的程度是PM毒性潜力的关键决定因素PM的肺毒性效应的确切细胞和分子机制尚未完全确定。然而，这些机制可能取决于PM与包括DNA、脂类和蛋白质在内的一系列生物分子相互作用和修饰的能力。越来越多的证据表明，PM引起的DNA损伤和细胞凋亡是由于各种颗粒物引起的铁源性活性氧(ROS)作为重要的第二毒性信使所致。 众所周知，各种DNA损伤剂，如氧化剂，产生的信号会聚到细胞周期停滞或细胞凋亡。氧化应激对细胞周期进程的控制与进入细胞周期的S阶段之前的检查点机制的激活有关。一个反馈控制被激活，作为细胞周期的刹车，以抑制进入S阶段，直到DNA修复完成。通过G1期和G1-S转变的过程涉及细胞周期机制、细胞周期蛋白和细胞周期蛋白依赖性蛋白激酶(CDK)的关键调控因子的顺序组装和激活。然而，目前还没有关于空气颗粒物诱导对这种细胞周期机制进行调控的信息。 我们的初步数据显示，PM诱导AEC细胞周期停滞，并改变对G1期细胞周期蛋白和细胞周期蛋白依赖性激酶的调节。这项建议的具体目的是1)确定环境空气污染颗粒物是否通过改变AEC中产生的活性氧对G1周期蛋白的调节而导致细胞周期停滞。2)探讨铁源性自由基是否参与了PM诱导的AEC细胞周期调控靶基因的表达改变和翻译后修饰。3)确定PM诱导的细胞周期停滞是否通过激活线粒体死亡途径的G1期细胞周期蛋白和CDKs的调节而起作用。我们拟议的工作将使我们能够理解环境空气颗粒物引起的肺部疾病的分子和生物学基础。

DESCRIPTION (provided by applicant): Ambient air pollution particle (PM) is associated with increased morbidity and mortality resulting from acute and chronic cardiopulmonary injury including lung cancer. Recent investigations have demonstrated that PM is genotoxic to alveolar epithelial cell (AEC) by causing DMA damage and apoptosis. The extent of AEC injury and repair are critical determinants of the toxic potential of PM. The precise cellular and molecular mechanisms underlying the toxic pulmonary effects of PM are not fully established. However, the mechanisms may depend upon the ability of PM to interact with and modify a spectrum of biomolecules including DNA, lipids, and proteins. Accumulating evidence implicate PM induced DNA damage and apoptosis due to iron-derived reactive oxygen species (ROS) as important second messengers of toxicity due to a variety of particulates. It is known that various DNA-damaging agents such as oxidants generate signals that converge to either cell cycle arrest or apoptosis. Control of cell cycle progression in response to oxidative stress is linked to activation of a checkpoint mechanism operating before entry into the S phase of the cell cycle. A feedback control is activated that acts as a brake on the cell cycle to inhibit entry into the S phase until DNA repair is completed. Progression through the G1 phase and the G1-S transition involves sequential assembly and activation of key regulators of the cell cycle machinery, the Cyclins and cyclin-dependent kinases (CDKs). However, there is no information on airborne particulate matter induced regulation of this cell cycle machinery. Our preliminary data show that PM induces cell cycle arrest and alters regulation of G1 Cyclins and cyclin-dependent kinase in AEC. The specific aims of this proposal are 1) To determine whether ambient air pollution particulates induce cell cycle arrest via altered regulation of G1 cyclins by generation of reactive oxygen species in AEC. 2) To determine whether iron derived free radicals mediate PM-induced altered expression and posttranslational modification of cell cycle regulatory target genes in AEC. 3) To determine whether PM-induced cell cycle arrest is mediated by altered regulation of G1 Cyclins and CDKs that activate mitochondria) death pathway. Our proposed work will enable us to understand the molecular and biological basis of pathophysiology of ambient airborne particulate induced lung diseases.