51. LTBP2 is secreted from lung myofibroblasts and is a potential biomarker for idiopathic pulmonary fibrosis.
- Author
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Enomoto Y, Matsushima S, Shibata K, Aoshima Y, Yagi H, Meguro S, Kawasaki H, Kosugi I, Fujisawa T, Enomoto N, Inui N, Nakamura Y, Suda T, and Iwashita T
- Subjects
- Aged, Animals, Bleomycin pharmacology, Cells, Cultured, Female, Fibroblasts cytology, Fibroblasts drug effects, Fibroblasts metabolism, Gene Expression Profiling methods, Humans, Idiopathic Pulmonary Fibrosis blood, Idiopathic Pulmonary Fibrosis metabolism, Latent TGF-beta Binding Proteins blood, Latent TGF-beta Binding Proteins metabolism, Lung cytology, Male, Mice, Inbred C57BL, Middle Aged, Myofibroblasts cytology, Myofibroblasts drug effects, Transforming Growth Factor beta1 pharmacology, Biomarkers metabolism, Idiopathic Pulmonary Fibrosis genetics, Latent TGF-beta Binding Proteins genetics, Lung metabolism, Myofibroblasts metabolism
- Abstract
Although differentiation of lung fibroblasts into α-smooth muscle actin (αSMA)-positive myofibroblasts is important in the progression of idiopathic pulmonary fibrosis (IPF), few biomarkers reflecting the fibrotic process have been discovered. We performed microarray analyses between FACS-sorted steady-state fibroblasts (lineage (CD45, TER-119, CD324, CD31, LYVE-1, and CD146)-negative and PDGFRα-positive cells) from untreated mouse lungs and myofibroblasts (lineage-negative, Sca-1-negative, and CD49e-positive cells) from bleomycin-treated mouse lungs. Amongst several genes up-regulated in the FACS-sorted myofibroblasts, we focussed on Ltbp2 , the gene encoding latent transforming growth factor-β (TGF-β) binding protein-2 (LTBP2), because of the signal similarity to Acta2 , which encodes αSMA, in the clustering analysis. The up-regulation was reproduced at the mRNA and protein levels in human lung myofibroblasts induced by TGF-β1. LTBP2 staining in IPF lungs was broadly positive in the fibrotic interstitium, mainly as an extracellular matrix (ECM) protein; however, some of the αSMA-positive myofibroblasts were also stained. Serum LTBP2 concentrations, evaluated using ELISA, in IPF patients were significantly higher than those in healthy volunteers (mean: 21.4 compared with 12.4 ng/ml) and showed a negative correlation with % predicted forced vital capacity (r = -0.369). The Cox hazard model demonstrated that serum LTBP2 could predict the prognosis of IPF patients (hazard ratio for death by respiratory events: 1.040, 95% confidence interval: 1.026-1.054), which was validated using the bootstrap method with 1000-fold replication. LTBP2 is a potential prognostic blood biomarker that may reflect the level of differentiation of lung fibroblasts into myofibroblasts in IPF., (© 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)
- Published
- 2018
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