The Role and Biology of Fra-1 in Lung Injury and Repair

Fra-1 在肺损伤和修复中的作用和生物学

• 批准号: 8265096
• 负责人: Sekhar P. Reddy
• 金额: $ 30.49万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-15 至 2013-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8265096
• 关键词: Acute; Acute Lung Injury; Affect; Antioxidants; Biological; Biological Assay; Biology; Cell Death; Cells; Cellular Stress; Chronic lung disease; DNA Damage; Data; Development; Disease; Elements; Endotoxins; Enzymes; Epithelial; Epithelial Cells; Equilibrium; Experimental Models; Exposure to; FOS gene; FOSL1 gene; Funding; Gene Expression; Gene Targeting; Genetic Transcription; Grant; Health; Homeostasis; Human; Hyperoxia; In Vitro; Inflammation; JUN gene; Link; Lung; Lung Inflammation; Lung diseases; Malignant Neoplasms; Mitogen-Activated Protein Kinases; Modeling; Monitor; Mus; Non-Malignant; Oncogenic; Oxidative Stress; Pathogenesis; Pathologic; Pathologic Processes; Pattern; Physiological; Play; Predisposition; Process; Proto-Oncogenes; Regulation; Reporter; Resistance; Role; Serum Response Element; Signal Transduction; Stimulus; Testing; Therapeutic Agents; Time; Tissues; Toxic Environmental Substances; Transcription Coactivator; Transcription Factor AP-1; Transcription Repressor/Corepressor; Tumor Promoters; bZIP Domain; base; cancer cell; cell injury; cell motility; cell type; cigarette smoke-induced; in vivo; injury and repair; insight; lung injury; mortality; mouse model; novel; novel therapeutics; optical imaging; overexpression; pathogen; promoter; response; toxicant; transcription factor

DESCRIPTION (provided by applicant): A balancing act between transcriptional "activators" and "repressors" appears to play a key role in maintaining tissue homeostasis. However, shifting the balance in favor of activator or repressor functions can deregulate transcription (the initial step in gene expression), ultimately leading to a pathologic state. Indeed, emerging data have causally linked abnormal expression of genes involved in injury and repair to a wide variety of environmental insults, which either cause or enhance susceptibility to a variety of pathologic states, including acute and chronic lung diseases. This competing renewal application is focused on expanding our ongoing studies of the novel roles of Fra1 transcription in lung injury and repair. Fra1 is a dimeric partner of AP1 (Jun/Fos), which is activated by environmental insults and regulates gene expression that is involved in both normal and pathologic processes. During the last funding period, we have shown that interplay between the upstream promoter elements and the serum response element drives the Fra1 induction. We have shown that ectopic Fra1 promotes lung cell motility and invasion in vitro, but it requires other activated protooncogene(s) to impart its oncogenic potential in vivo. Although emerging data have unequivocally demonstrated a causative role for Fra1 in cancer cell progression and invasion, the exact role of Fra1 in non-malignant lung diseases remains unclear. Intriguingly, we have found that deletion of Fra1 confers increased protection against prooxidant-induced lung injury, when compared to results in control mice. We have also found that Fra1-deficient cells are remarkably more resistant than Fra1-sufficient cells to prooxidant-induced cell death. In reporter assays, ectopic Fra1 expression decreased both AP1-dependent and -independent transcriptional responses in lung epithelial cells. Based on these novel preliminary observations, we hypothesize that Fra1 functions as a "transcriptional repressor," thereby playing a key role in promoting cellular injury and lung pathogenesis. To test our hypothesis and to further to dissect Fra1 promoter regulation, we propose the following specific aims: 1) To determine the mechanisms involved in protection against prooxidant exposure by Fra1 deficiency using gene-targeted mice and experimental models of acute lung injury, 2) to dissect the critical factors that regulate basal-level and inducible Fra1 expression in vitro; and 3) to examine the patterns of Fra1 induction in lung disease and during injury and repair by using tdTomato-based noninvasive optical imaging in vivo and ex vivo. The proposed studies are not only novel in terms of elucidating the biology and functions of Fra1 but will also provide critical insights into the mechanistic basis underlying prooxidant-induced cellular stress and non-malignant lung pathogenesis. Because cellular stress is an integral part of many lung diseases and malignancy, these results could enable us to target Fra1, or steps that specifically regulate Fra1, as novel therapeutic agent(s). PUBLIC HEALTH RELEVANCE: Understanding the role of Fra1 in acute lung injury and delineating the mechanisms underlying FRA1 induction and the development of noninvasive red florescence-based optical imaging of human FRA1 promoter activation in vivo will be helpful in allowing us to monitor and track the host transcriptional response to proxidants and toxicants over time in cells that are undergoing injury and repair or are associated with a pathological/disease state. The results obtained from this study will be of great significance for our understanding of disease mechanisms such as oxidative stress, DNA damage, and inflammation regulated by MAP kinase/AP1-Fra1 signaling in response to stressful stimuli.

描述（由申请人提供）：转录“激活剂”和“阻抑剂”之间的平衡作用似乎在维持组织稳态中发挥着关键作用。然而，改变平衡以支持激活子或阻遏子功能可能会解除转录（基因表达的初始步骤）的调节，最终导致病理状态。事实上，新出现的数据已将参与损伤和修复的基因的异常表达与多种环境损害联系起来，这些环境损害要么导致或增强对各种病理状态的易感性，包括急性和慢性肺部疾病。这项竞争性更新应用的重点是扩大我们正在进行的关于 Fra1 转录在肺损伤和修复中的新作用的研究。 Fra1 是 AP1 (Jun/Fos) 的二聚体伴侣，可通过环境损伤激活并调节参与正常和病理过程的基因表达。在上一个资助期间，我们已经证明上游启动子元件和血清反应元件之间的相互作用驱动 Fra1 诱导。我们已经表明，异位 Fra1 在体外促进肺细胞运动和侵袭，但它需要其他激活的原癌基因才能在体内赋予其致癌潜力。尽管新出现的数据明确证明了 Fra1 在癌细胞进展和侵袭中的致病作用，但 Fra1 在非恶性肺部疾病中的确切作用仍不清楚。有趣的是，我们发现与对照小鼠的结果相比，Fra1 的缺失可以增强对促氧化剂诱导的肺损伤的保护。我们还发现，Fra1 缺陷的细胞比 Fra1 充足的细胞对促氧化剂诱导的细胞死亡具有更强的抵抗力。在报告基因检测中，异位 Fra1 表达降低了肺上皮细胞中 AP1 依赖性和非依赖性转录反应。基于这些新颖的初步观察，我们假设 Fra1 作为“转录抑制因子”发挥作用，从而在促进细胞损伤和肺部发病机制中发挥关键作用。为了检验我们的假设并进一步剖析 Fra1 启动子调控，我们提出以下具体目标：1) 使用基因靶向小鼠和急性肺损伤实验模型来确定 Fra1 缺陷导致的促氧化剂暴露保护机制，2)剖析调节基础水平和体外诱导型 Fra1 表达的关键因素； 3) 通过使用基于 tdTomato 的体内和离体无创光学成像来检查肺部疾病以及损伤和修复过程中 Fra1 的诱导模式。拟议的研究不仅在阐明 Fra1 的生物学和功能方面具有新颖性，而且还将为促氧化剂诱导的细胞应激和非恶性肺发病机制的机制基础提供重要的见解。由于细胞应激是许多肺部疾病和恶性肿瘤的一个组成部分，因此这些结果可以使我们能够以 Fra1 或特异性调节 Fra1 的步骤为目标，作为新型治疗剂。公共健康相关性：了解 Fra1 在急性肺损伤中的作用，描述 FRA1 诱导的机制，以及开发基于红色荧光的人体内 FRA1 启动子激活的非侵入性光学成像，将有助于我们监测和追踪宿主随着时间的推移，正在经历损伤和修复或与病理/疾病状态相关的细胞对氧化剂和毒物的转录反应。这项研究获得的结果对于我们理解应激刺激下MAP激酶/AP1-Fra1信号调节的氧化应激、DNA损伤和炎症等疾病机制具有重要意义。