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: 7780060
• 负责人: Sekhar P. Reddy
• 金额: $ 36.53万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 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/7780060
• 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; Homeostasis; Human; Hyperoxia; In Vitro; Inflammation; JUN gene; Link; Lung; 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; novel; novel therapeutics; optical imaging; overexpression; pathogen; promoter; public health relevance; 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“阻遏物”之间的平衡行为似乎在维持组织稳态方面起着关键作用。但是，转移平衡以支持激活因子或阻遏物函数可以放松调节转录（基因表达的初始步骤），最终导致病理状态。实际上，新兴数据与损伤和修复有关的基因的因果关系异常连接到各种环境损伤，这会导致或增强对包括急性和慢性肺部疾病在内的多种病理状态的敏感性。这种竞争性更新应用的重点是扩大我们对FRA1转录在肺损伤和修复中的新作用的持续研究。 FRA1是AP1（JUN/FOS）的二聚体合作伙伴，它被环境损伤激活，并调节与正常和病理过程有关的基因表达。在最后一个资金期间，我们表明上游启动子元素与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在体外促进了肺部细胞的运动和侵袭，但它要求其他活化的原子量在体内赋予其致癌潜力。尽管新兴数据明确证明了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尚不清楚。有趣的是，与对照小鼠的结果相比，FRA1的缺失赋予了对促氧化剂诱导的肺损伤的保护。我们还发现，FRA1缺陷型细胞比FRA1充足的细胞更具耐药性，对促氧化剂诱导的细胞死亡。在报告基因测定中，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起着“转录阻遏物”的作用，从而在促进细胞损伤和肺发病机理中起关键作用。为了检验我们的假设并进一步剖析FRA1启动子调节，我们提出了以下具体目的：1）确定使用基因靶向的小鼠和急性肺损伤的实验模型的FRA1缺乏症的保护涉及的机制，2）以调节基本水平和含糊不清的FRA表达的关键因素。 3）检查肺部疾病中FRA1诱导的模式，以及在体内和Ex Vivo中使用基于TDTOMATO的非侵入性光学成像的损伤和修复模式。拟议的研究不仅在阐明FRA1的生物学和功能方面是新颖的，而且还将为基础培养剂诱导的细胞应激和非机敏性肺发病机理提供关键的见解。由于细胞应激是许多肺部疾病和恶性肿瘤的组成部分，因此这些结果可以使我们能够靶向FRA1或专门调节FRA1的步骤，作为新型治疗剂。公共卫生相关性：了解FRA1在急性肺损伤中的作用，并描述FRA1诱导的机制以及对体内人类FRA1启动子激活的非侵染性红色光学成像的发展将有助于我们使我们能够监测和跟踪对宿主的疾病和毒性的疾病和毒性的影响，使其与毒性和毒性相关联/毒素的疾病和毒性相关。从这项研究中获得的结果对于我们对疾病机制的理解将具有重要意义，例如氧化应激，DNA损伤和MAP激酶/AP1-FRA1信号对应激刺激的响应。