Bone Morphogenetic Protein-7 Antagonizes Myocardial Fibrosis Induced by Atrial Fibrillation by Restraining Transforming Growth Factor-β (TGF-β)/Smads Signaling
Xinjun Chen, Jing Xu, Baozhou Jiang, Danping Liu
(Emergency Internal Medicine, Shaanxi Province People’s Hospital, Xi’an, Shaanxi, China (mainland))
Med Sci Monit 2016; 22:3457-3468
This aim of this study was to investigate the expression of BMP-7 in atrial fibrillation and illuminate the role of BMP-7 and TGF-β/Smads signaling in myocardial fibrosis.
MATERIAL AND METHODS: Fibrosis of myocardial fibroblasts was induced by TGF-β1 and the optimal condition was determined by the MTT assay. Cells with TGF-β1 treatment were sub-divided into 4 groups: TGF-β1 group, TGF-β1 + Smad3 siRNA group, TGF-β1 + BMP-7 group, and TGF-β1 + BMP-7 + Smad1/5 siRNA group. Cells were then analyzed by detecting the expression of epithelial cadherin (E-cadherin), collagen I, alpha smooth muscle cell actin (α-SMA), and activated Smads using Western blot. Mice were injected daily with Ach-CaCl2 with or without the addition of BMP-7 and Smad1/5 siRNA over a period of 4 weeks. Cardiac functions were tested by echocardiogram assay and fibrosis was diagnosed by histopathological examination. Finally, molecule biomarkers were detected using standard procedures.
RESULTS: TGF-β1 treatment significantly down-regulated E-cadherin expression and up-regulated expressions of Collagen I, α-SMA, and pSmad3 (P<0.05). The effects of TGF-β1 treatment can be significantly suppressed by Smad3 siRNA (P<0.05). Cells in the BMP-7 group exhibited significantly higher expression levels of E-cadherin and pSmad1/5 together with lower expression levels of pSmad3, collagen I, and a-SMA (P<0.05). Moreover, Smad1/5 siRNA can substantially repress the effects of BMP-7 (P<0.05) and results from th... read more
Keywords: Atrial Fibrillation, Bone Morphogenetic Protein Receptors, Endomyocardial Fibrosis, Latent TGF-beta Binding Proteins, Smad3 Protein