Abstract
Rationale: Epithelial-mesenchymal transition (EMT) is supposed to be implicated in the pathogenesis of lung fibrosis through enhanced TGF-b1 signaling. TNF-a has also been implicated in tissue fibrosis. Recently, TGF-b induced EMT is augmented by TNF-a, suggesting that enhanced EMT by TNF-a may be important in the pathological processed of lung diseases. However, the mechanism of enhanced EMT by TNF-a has not been fully elucidated. Therefore, we evaluated the cytokine/ chemokine profiles of the cells that underwent EMT by TGF-b and/or TNF-a.
Methods: A549 cells were incubated for 48 hours with 5 ng/ml of TGF-b1, 10 ng/ml of TNF-a, or TGF-b1 and TNF-a to undergo EMT. After 48 hours incubation, growth medium was changed to serum-free medium, and the supernatants were collected at 48 hours. Cytokine/ chemokine array was performed using Ray Bio human cytokine array V. Relative values were quantified by densitometry, and normalized to that obtained in non-treated sample.
Results: TNF-a induced production of inflammatory chemokines, such as RANTES and MCP-1. TGF-b induced production of inflammatory chemokines, including GM-CSF, GRO, GRO-a, MCP-2, and MCP-3. Simultaneous stimulation with TNF-a and TGF-b induced production of GM-CSF, GRO, GRO-a, IL6, MCP-1, RANTES, and these effects were enhanced on the production of GRO, GRO-a, IL-8, and MCP-1.
Conclusion: The cells treated with TGF-b1 or TNF-a have different chemokine profile, and the effect on chemokines production was enhanced by the combination with TGF-b1 and TNF-a. This study might contribute to understanding mechanism of EMT enhanced by TNF-a and pathogenesis of lung fibrosis.
- © 2012 ERS
