BMP-7 Does Not Protect against Bleomycin-Induced Lung or Skin Fibrosis

Bone morphogenic protein (BMP)-7 is a member of the BMP family which are structurally and functionally related, and part of the TGF beta super family of growth factors. BMP-7 has been reported to inhibit renal fibrosis and TGF beta 1-induced epithelial-mesenchymal transition (EMT), in part through negative interactions with TGF beta 1 induced Smad 2/3 activation. We utilized in vivo bleomycin-induced fibrosis models in the skin and lung to determine the potential therapeutic effect of BMP-7. We then determined the effect of BMP-7 on TGF beta 1-induced EMT in lung epithelial cells and collagen production by human lung fibroblasts. We show that BMP-7 did not affect bleomycin-induced fibrosis in either the lung or skin in vivo; had no effect on expression of pro-fibrotic genes by human lung fibroblasts, either at rest or following exposure to TGF beta 1; and did not modulate TGF beta 1-induced EMT in human lung epithelial cells. Taken together our data indicates that BMP-7 has no antifibrotic effect in lung or skin fibrosis either in vivo or in vitro. This suggests that the therapeutic options for BMP-7 may be confined to the renal compartment.