title: Visualization of Fra-1/AP-1 activation during LPS-induced inflammatory lung injury using fluorescence optical imaging.
abstract: Inappropriate lung inflammatory response following oxidant and toxicant exposure can lead to abnormal repair and disease pathogenesis, including fibrosis. Thus early detection of molecular and cellular processes and mediators promoting lung inflammation is necessary to develop better strategies for therapeutic intervention and disease management. Previously, we have shown that transcription factor Fra-1/AP-1 plays key roles in lung inflammatory response, as Fra-1-null mice are less susceptible than wild-type mice to LPS-induced lung injury and mortality. Herein, we developed a transgenic reporter mouse model expressing tdTomato under the control of FRA-1 (human) promoter (referred to as FRA-1(TdTg) mice) to monitor its activation during inflammatory lung injury using fluorescence protein-based optical imaging and molecular analysis in vivo and ex vivo. A higher red fluorescent signal was observed in the lungs of LPS-treated FRA-1(TdTg) mice compared with vehicle controls, and Western blot and qRT-PCR analyses revealed a significant correlation with the FRA-1-tdTomato reporter expression. Immunocolocalization demonstrated expression of FRA-1-tdTomato largely in lung alveolar macrophages and to some extent in epithelial cells. Moreover, we validated these results with a second reporter mouse model that expressed green fluorescent protein upon activation of endogenous Fra-1 promoter. Additionally, we demonstrated increased expression of FRA-1 in alveolar macrophages in human lung instilled with Escherichia coli ex vivo. Collectively, our data obtained from two independent reporter mouse models and from human samples underscore the significance of Fra-1 activation in alveolar macrophages during inflammatory lung injury and may aid in developing strategies to target this transcription factor in lung injury and repair.
authors.affiliation: Division of Developmental Biology and Basic Research, Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois;
authors.forename: Subbiah
authors.initials: S
authors.lastname: Rajasekaran
authors.affiliation: Division of Developmental Biology and Basic Research, Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois;
authors.forename: Chandramohan R
authors.initials: CR
authors.lastname: Tamatam
authors.affiliation: Division of Developmental Biology and Basic Research, Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois;
authors.forename: Haranatha R
authors.initials: HR
authors.lastname: Potteti
authors.affiliation: Division of Cancer Imaging Research, Department of Radiology and Radiological Sciences, The Johns Hopkins University, Baltimore, Maryland;
authors.forename: Venu
authors.initials: V
authors.lastname: Raman
authors.affiliation: Departments of Medicine and Anesthesia, Cardiovascular Research Institute, University of California, San Francisco, California;
authors.forename: Jae-Woo
authors.initials: JW
authors.lastname: Lee
authors.affiliation: Departments of Medicine and Anesthesia, Cardiovascular Research Institute, University of California, San Francisco, California;
authors.forename: Michael A
authors.initials: MA
authors.lastname: Matthay
authors.affiliation: Department of Pharmacology, College of Medicine, University of Illinois at Chicago, Chicago, Illinois.
authors.forename: Dolly
authors.initials: D
authors.lastname: Mehta
authors.affiliation: Division of Developmental Biology and Basic Research, Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois; sreddy03@uic.edu.
authors.forename: Narsa M
authors.initials: NM
authors.lastname: Reddy
authors.affiliation: Division of Developmental Biology and Basic Research, Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois;
authors.forename: Sekhar P
authors.initials: SP
authors.lastname: Reddy
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology*; D055370:Lung Injury / Q000276:immunology / Q000378:metabolism*; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D011401:Promoter Regions, Genetic; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D000099169:Fos-Related Antigen 1
chemical_list: D008070:Lipopolysaccharides; D016760:Proto-Oncogene Proteins c-fos; D018808:Transcription Factor AP-1; D000099169:Fos-Related Antigen 1
keywords: Fra-1; acute lung injury; fluorescence; in vivo imaging; tdTomato