Effect of budesonide on TGF-beta1-enhanced VEGF production by lung fibroblasts

VEGF (vascular endothelial growth factor) is a potent proangiogenic cytokine, and vascular change is one of the characteristic features of airway remodelling. Since the glucocorticoids have shown antifibrosis properties, we sought to investigate whether budesonide, a widely used glucocorticoid in clinical practice, could attenuate TGF-beta1 (transforming growth factor-beta1)-induced VEGF production by HFL-1 (human lung fibroblasts). HFL-1 fibroblasts were treated with various concentrations of budesonide (10(-11) M, 10(-9) M and 10(-7) M) in the absence or presence of TGF-beta1. Postculture media were collected for ELISA of VEGF at the indicated times. The cell lysates were subjected to Western blotting analysis to test TGF-beta1/Smad and MAP (mitogen-activated protein) kinase signalling activation, respectively. The results suggested that budesonide pretreatment reduced the significant increase of VEGF release induced by TGF-beta1 in HFL-1 fibroblasts in a dose-dependent manner, and suppressed the increase of phospho-Smad3 and phosphor-ERK (extracellular signal-regulated kinase) protein levels. In conclusion, budesonide may reduce TGF-beta1-induced VEGF production in the lung, probably through the Smad/ERK signalling pathway and, thus, may provide new sight into the molecular mechanism underlying glucocorticoid therapy for airway inflammatory diseases.