Idiopathic pulmonary fibrosis (IPF) is an incurable, fatal disease with increasing incidence and mortality. Despite coordinated attempts to rapidly translate findings from in vitro and preclinical models into improved care, there have been few major therapeutic breakthroughs. The nature of the intercellular communications leading to altered cellular phenotypes in IPF is poorly characterized. We have demonstrated that the cell surface glycoprotein Thy-1 is a fibrosis suppressor which modulates critical aspects of the fibrogenic phenotype in lung fibroblasts. We have found that in response to stress, fibroblasts release membrane-originating extracellular vesicles (EV) containing membrane-bound Thy-1. In bronchial lavage fluid (BALF) from IPF patients, the level of EV-associated Thy-1 correlates with numbers of fibroblastic foci on biopsy, suggesting that Thy-1+ EV may be useful biomarkers of disease activity. In other fields such as cancer and immunology, EV such as exosomes are increasingly appreciated as critical in cell-cell communication;they usually contain non-coding RNA and mRNA that are taken up by recipient cells and alter their phenotypes. Also, EV have been found to be excellent biomarkers in many diseases. Recently, supernatants from mesenchymal stem cells (MSC), which contain EV, have been shown to promote repair of neonatal lung injury, suggesting that EV transmit potent signals relevant to lung injury and repair. Based on these findings, we hypothesize that extracellular vesicles (EV) from activated fibroblasts sustain and amplifiy, whereas MSC- derived EV inhibit, profibrotic cellular phenotypes in pulmonary fibrosis. The following specific aims will test the hypothesis: 1: To define the molecular characteristics of EV released in response to profibrotic stimuli, by characterizing EV released from lung fibroblasts and MSCs in response to fibrogenic stimuli;2. To define the role of EV in the phenotypic modification of lung cells, by co-culturing fibroblasts and MSC in EV derived from relevant normal and profibrotic cell types, and measuring their uptake and effect on cell phenotype;and 3. To define the role of EV in fibrosis, by characterizing the EV produced in animal models of lung fibrosis and IPF, and by delivering fibroblast- or MSC-derived EV in animal models of fibrosis to determine their fibrogenic and therapeutic effects. Defining the "vesiculome" relevant to lung fibrosis is critical to understanding and modifying intercellular communication in this pernicious disorder.

Public Health Relevance

Despite decades of research on idiopathic pulmonary fibrosis (IPF), this destructive lung disease is increasing in incidence and claiming as many lives annually as breast cancer does. Lung cells in fibrotic disease communicate with each other to promote the spreading of destructive scar tissue throughout the lung. Understanding an important mechanism of cell communication via extracellular vesicles will shed new light on this deadly process and uncover novel avenues for treatment.

National Institute of Health (NIH)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Eu, Jerry Pc
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of California San Diego
Schools of Medicine
La Jolla
United States
Zip Code
Glasser, Stephan W; Hagood, James S; Wong, Simon et al. (2016) Mechanisms of Lung Fibrosis Resolution. Am J Pathol 186:1066-77
Hagood, James S (2014) Beyond the genome: epigenetic mechanisms in lung remodeling. Physiology (Bethesda) 29:177-85
Sanders, Yan Y; Hagood, James S; Liu, Hui et al. (2014) Histone deacetylase inhibition promotes fibroblast apoptosis and ameliorates pulmonary fibrosis in mice. Eur Respir J 43:1448-58
Bradley, John E; Chan, Joy M; Hagood, James S (2013) Effect of the GPI anchor of human Thy-1 on antibody recognition and function. Lab Invest 93:365-74
Sanders, Yan Y; Ambalavanan, Namasivayam; Halloran, Brian et al. (2012) Altered DNA methylation profile in idiopathic pulmonary fibrosis. Am J Respir Crit Care Med 186:525-35
Varisco, Brian M; Ambalavanan, Namasivayam; Whitsett, Jeffrey A et al. (2012) Thy-1 signals through PPARγ to promote lipofibroblast differentiation in the developing lung. Am J Respir Cell Mol Biol 46:765-72
Dell, Sharon; Cernelc-Kohan, Matejka; Hagood, James S (2012) Diffuse and interstitial lung disease and childhood rheumatologic disorders. Curr Opin Rheumatol 24:530-40
Huang, Wen-Tan; Vayalil, Praveen K; Miyata, Toshio et al. (2012) Therapeutic value of small molecule inhibitor to plasminogen activator inhibitor-1 for lung fibrosis. Am J Respir Cell Mol Biol 46:87-95
Kis, Kornelia; Liu, Xiaoqiu; Hagood, James S (2011) Myofibroblast differentiation and survival in fibrotic disease. Expert Rev Mol Med 13:e27
Ramirez, Gustavo; Hagood, James S; Sanders, Yan et al. (2011) Absence of Thy-1 results in TGF-ýý induced MMP-9 expression and confers a profibrotic phenotype to human lung fibroblasts. Lab Invest 91:1206-18

Showing the most recent 10 out of 22 publications