Angiotensin-(1-7) decreases the expression of collagen I via TGF-β1/Smad2/3 and subsequently inhibits fibroblast-myofibroblast transition.

Previous studies have shown that the RAS (renin-angiotensin system) might participate in airway remodelling in asthma. As a main component of the RAS, Ang-(1-7) [angiotensin-(1-7)] has been reported in few studies regarding its protective effect on asthma. However, the functional roles and relevant signalling pathways of Ang-(1-7) have not been well illustrated. In the present study, we analysed the effect of Ang-(1-7) on AngII (angiotensin II)-induced HLF (human lung fibroblast)-MF (myofibroblast) transition by detecting Col-I (collagen type I), TGF-β1 (transforming growth factor-β1) and α-SMA (α-smooth muscle actin) expression. We explored further the possible signalling pathways involved in HLF-MF transition. Our results showed that Ang-(1-7) could down-regulate the expression of Col-I, α-SMA and TGF-β1/Smad2/3 (all P<0.05). A significant decrease was found in phosphorylation of PI3K (phosphoinositide 3-kinase), Akt, p38-MAPK (mitogen-activated protein kinase) and JNK (c-Jun N-terminal kinase) signalling pathways during HLF-MF transition (all P<0.05). Our data suggests that Ang-(1-7) decreases the expression of Col-I via TGF-β1/Smad2/3 and subsequently inhibits HLF-MF transition.