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.

National Institute of Health (NIH)
National Institute of Environmental Health Sciences (NIEHS)
Research Project (R01)
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Lung Injury, Repair, and Remodeling Study Section (LIRR)
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Nadadur, Srikanth
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University of Illinois at Chicago
Schools of Medicine
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Mezu-Ndubuisi, Olachi J; Wanek, Justin; Chau, Felix Y et al. (2014) Correspondence of retinal thinning and vasculopathy in mice with oxygen-induced retinopathy. Exp Eye Res 122:119-22
Mittal, Manish; Siddiqui, Mohammad Rizwan; Tran, Khiem et al. (2014) Reactive oxygen species in inflammation and tissue injury. Antioxid Redox Signal 20:1126-67
Mezu-Ndubuisi, Olachi J; Teng, Pang-yu; Wanek, Justin et al. (2013) In vivo retinal vascular oxygen tension imaging and fluorescein angiography in the mouse model of oxygen-induced retinopathy. Invest Ophthalmol Vis Sci 54:6968-72
Potteti, Haranatha R; Reddy, Narsa M; Hei, Tom K et al. (2013) The NRF2 activation and antioxidative response are not impaired overall during hyperoxia-induced lung epithelial cell death. Oxid Med Cell Longev 2013:798401
Huang, Long Shuang; Berdyshev, Evgeny; Mathew, Biji et al. (2013) Targeting sphingosine kinase 1 attenuates bleomycin-induced pulmonary fibrosis. FASEB J 27:1749-60
Rajasekaran, Subbiah; Reddy, Narsa M; Zhang, Wei et al. (2013) Expression profiling of genes regulated by Fra-1/AP-1 transcription factor during bleomycin-induced pulmonary fibrosis. BMC Genomics 14:381
Ramchandran, Ramaswamy; Pilipenko, Evgeny; Bach, Laura et al. (2012) Hypoxic regulation of pulmonary vascular smooth muscle cyclic guanosine monophosphate-dependent kinase by the ubiquitin conjugating system. Am J Respir Cell Mol Biol 46:323-30
Yusuf, Dimas; Butland, Stefanie L; Swanson, Magdalena I et al. (2012) The transcription factor encyclopedia. Genome Biol 13:R24
Vaz, Michelle; Machireddy, Narsa; Irving, Ashley et al. (2012) Oxidant-induced cell death and Nrf2-dependent antioxidative response are controlled by Fra-1/AP-1. Mol Cell Biol 32:1694-709
Vaz, Michelle; Reddy, Narsa M; Rajasekaran, Subbiah et al. (2012) Genetic disruption of Fra-1 decreases susceptibility to endotoxin-induced acute lung injury and mortality in mice. Am J Respir Cell Mol Biol 46:55-62

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