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Rajasekaran S, Tamatam CR, Potteti HR, Raman V, Lee JW, Matthay MA, Mehta D, Reddy NM, Reddy SP. Visualization of Fra-1/AP-1 activation during LPS-induced inflammatory lung injury using fluorescence optical imaging. Am J Physiol Lung Cell Mol Physiol 2015; 309:L414-24. [PMID: 26071555 DOI: 10.1152/ajplung.00315.2014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 06/08/2015] [Indexed: 01/11/2023] Open
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.
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Affiliation(s)
- Subbiah Rajasekaran
- Division of Developmental Biology and Basic Research, Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois
| | - Chandramohan R Tamatam
- Division of Developmental Biology and Basic Research, Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois
| | - Haranatha R Potteti
- Division of Developmental Biology and Basic Research, Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois
| | - Venu Raman
- Division of Cancer Imaging Research, Department of Radiology and Radiological Sciences, The Johns Hopkins University, Baltimore, Maryland
| | - Jae-Woo Lee
- Departments of Medicine and Anesthesia, Cardiovascular Research Institute, University of California, San Francisco, California
| | - Michael A Matthay
- Departments of Medicine and Anesthesia, Cardiovascular Research Institute, University of California, San Francisco, California
| | - Dolly Mehta
- Department of Pharmacology, College of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Narsa M Reddy
- Division of Developmental Biology and Basic Research, Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois;
| | - Sekhar P Reddy
- Division of Developmental Biology and Basic Research, Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois
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Dorward DA, Lucas CD, Rossi AG, Haslett C, Dhaliwal K. Imaging inflammation: molecular strategies to visualize key components of the inflammatory cascade, from initiation to resolution. Pharmacol Ther 2012; 135:182-99. [PMID: 22627270 DOI: 10.1016/j.pharmthera.2012.05.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 05/07/2012] [Indexed: 12/19/2022]
Abstract
Dysregulation of inflammation is central to the pathogenesis of innumerable human diseases. Understanding and tracking the critical events in inflammation are crucial for disease monitoring and pharmacological drug discovery and development. Recent progress in molecular imaging has provided novel insights into spatial associations, molecular events and temporal sequelae in the inflammatory process. While remaining a burgeoning field in pre-clinical research, increasing application in man affords researchers the opportunity to study disease pathogenesis in humans in situ thereby revolutionizing conventional understanding of pathophysiology and potential therapeutic targets. This review provides a description of commonly used molecular imaging modalities, including optical, radionuclide and magnetic resonance imaging, and details key advances and translational opportunities in imaging inflammation from initiation to resolution.
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Affiliation(s)
- D A Dorward
- MRC Centre for Inflammation Research, The Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK.
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