Epithelial Cell Cycle Regulation by Elastase

弹性蛋白酶对上皮细胞周期的调节

• 批准号: 7099872
• 负责人: BERNARD M FISCHER
• 金额: $ 23.31万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7099872
• 关键词: DNA damage; DNA repair; cell cycle; cell line; cell proliferation; cytogenetics; elastases; enzyme activity; flow cytometry; free radical oxygen; gene expression; immunocytochemistry; kinase inhibitor; neutrophil; oxidative stress; oxidoreductase; quinones; respiratory epithelium; small interfering RNA; western blottings

DESCRIPTION (provided by applicant): Respiratory morbidity and mortality in patients with cystic fibrosis (CF), chronic bronchitis (CB), and pollution- or viral-triggered asthma results from chronic neutrophil-dominant inflammation. These patients are plagued by progressive airway obstruction, parenchyma! damage and scarring. Neutrophil elastase (NE), a serine protease released by neutrophils is present in the airways of these patients and injures the airway epithelium. We have reported that as part of the mechanism of NE-regulation of MUC5AC mucin gene expression, NE triggers the generation of intracellular reactive oxygen species (ROS). We examined the epithelial response to NE - mediated oxidative injury. Although, NE did not cause cell death, it did cause a G1 cell cycle arrest corresponding to a marked decrease in epithelial DNA synthesis and proliferation. Further, we demonstrate that NE- generated ROS mediate the decrease in DNA synthesis. In this proposal, we establish a previously unrecognized mechanism employed by the airway epithelium to reestablish homeostasis following NE-induced injury. The Hypothetical Schema to be addressed is: NE triggers the generation of intracellular reactive oxygen species (ROS) by NAD(P)H:quinone oxidoreductase 1 (NQ01), specifically superoxide and hydrogen peroxide. As a result of oxidant stress and consequential DNA damage, there is increased expression of the Cip/Kip family of mitotic inhibitors. Increased expression of these Cip/Kip proteins results in G1 arrest and inhibition of cell cycle progression and epithelial proliferation. This pause in the cell cycle allows for subsequent DNA repair followed by restoration of epithelial proliferation. The Specific Aims are: 1) To determine whether or not NE - induced DNA damage and G1 cell cycle arrest are mediated by reactive oxygen species; 2) To determine whether or not NE - induced molecular regulation and expression of the Cip/Kip family of mitotic inhibitors, p21, p27 and p57, is mediated by reactive oxygen species; 3) To determine whether or not NE - induced inhibition of DNA synthesis and cell cycle arrest are mediated by the Cip/Kip family of mitotic inhibitors - p21, p27, and p57. The information derived from these experiments will provide fundamental insights into epithelial response to injury, and provide a foundation to investigate normal epithelial regeneration versus pathologic remodeling.

描述（由申请人提供）：囊性纤维化患者（CF），慢性支气管炎（CB）和污染或病毒触发的哮喘的呼吸道发病率和死亡率。这些患者受到渐进式气道阻塞的困扰，实质！损坏和疤痕。中性粒细胞弹性蛋白酶（NE），嗜中性粒细胞释放的丝氨酸蛋白酶存在于这些患者的气道中，并伤害气道上皮。我们报告说，作为MUC5AC粘蛋白基因表达的NE-调节机制的一部分，NE触发了细胞内活性氧（ROS）的产生。我们检查了对NE介导的氧化损伤的上皮反应。尽管NE并未引起细胞死亡，但确实引起了G1细胞周期停滞，对应于上皮DNA合成和增殖的显着降低。此外，我们证明了Ne-ne-ne-ROS介导DNA合成的降低。在此提案中，我们建立了一种先前未认识到的机制，该机制是在NE诱导的损伤后重新建立稳态以重建稳态的。要解决的假设模式是：NE触发NAD（P）H：Quinone氧化还原酶1（NQ01）的细胞内活性氧（ROS）的产生，特别是超氧化物和过氧化氢。由于氧化剂应激和结果性DNA损伤，有丝分裂抑制剂的CIP/KIP家族的表达增加。这些CIP/KIP蛋白的表达增加会导致G1停滞并抑制细胞周期进展和上皮增殖。细胞周期中的这种停顿允许随后的DNA修复，然后恢复上皮增殖。具体目的是：1）确定NE诱导的DNA损伤和G1细胞周期停滞是否由活性氧介导； 2）确定有丝分裂抑制剂的CIP/KIP家族p21，p27和p57的NE诱导的分子调节和表达是否由活性氧介导； 3）确定NE诱导的DNA合成和细胞周期停滞的抑制是否由有丝分裂抑制剂的CIP/KIP家族介导-p21，p27和p57。从这些实验中得出的信息将为上皮反应提供基本见解，并为研究正常上皮再生与病理重塑的基础提供了基础。