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ABSTRACT: Background
Prostaglandin E2 (PGE2), the main metabolite of cyclooxygenase (COX), is a well-known anti-fibrotic agent. Moreover, myofibroblasts expressing ?-smooth muscle actin (?-SMA), fibroblast expansion and epithelial-mesenchymal transition (EMT) are critical to the pathogenesis of idiopathic pulmonary fibrosis (IPF). Our aim was to investigate the expression of COX-2 and PGE2 in human lung myofibroblasts and establish whether fibroblast-myofibroblast transition (FMT) and EMT are associated with COX-2 and PGE2 down-regulation.Methods
Fibroblasts obtained from IPF patients (n = 6) and patients undergoing spontaneous pneumothorax (control, n = 6) and alveolar epithelial cell line A549 were incubated with TGF-?1 and FMT and EMT markers were evaluated. COX-2 and ?-SMA expression, PGE2 secretion and cell proliferation were measured after IL-1? and PGE2 incubation.Results
Myofibroblasts from both control and IPF fibroblast cultures stimulated with IL-1? showed no COX-2 expression. IPF fibroblasts showed increased myofibroblast population and reduced COX-2 expression in response to IL-1?. TGF-?1 increased the number of myofibroblasts in a time-dependent manner. In contrast, TGF-?1 induced slight COX-2 expression at 4 h (without increase in myofibroblasts) and 24 h, but not at 72 h. Both IPF and control cultures incubated with TGF-?1 for 72 h showed diminished COX-2 induction, PGE2 secretion and ?-SMA expression after IL-1? addition. The latter decreased proliferation in fibroblasts but not in myofibroblasts. A549 cells incubated with TGF-?1 for 72 h showed down-regulated COX-2 expression and low basal PGE2 secretion in response to IL-1?. Immuno-histochemical analysis of IPF lung tissue showed no COX-2 immuno-reactivity in myofibroblast foci.Conclusions
Myofibroblasts are associated with COX-2 down-regulation and reduced PGE2 production, which could be crucial in IPF development and progression.
SUBMITTER: Gabasa M
PROVIDER: S-EPMC3670886 | biostudies-literature | 2013
REPOSITORIES: biostudies-literature
PloS one 20130603 6
<h4>Background</h4>Prostaglandin E2 (PGE2), the main metabolite of cyclooxygenase (COX), is a well-known anti-fibrotic agent. Moreover, myofibroblasts expressing α-smooth muscle actin (α-SMA), fibroblast expansion and epithelial-mesenchymal transition (EMT) are critical to the pathogenesis of idiopathic pulmonary fibrosis (IPF). Our aim was to investigate the expression of COX-2 and PGE2 in human lung myofibroblasts and establish whether fibroblast-myofibroblast transition (FMT) and EMT are asso ...[more]