title: Overexpression of Smad7 suppressed ROS/MMP9-dependent collagen synthesis through regulation of heme oxygenase-1.
abstract: We previously reported that AngiotensinII receptor blocker effectively inhibited TGF-β1-mediated epithelial-to-mesenchymal transition progress through regulating Smad7. However, the underlying mechanism by which Smad7 exerted in regulating MMP9 and fibrogenic response has not been fully elucidated. In the current study, we proved that NADPH p47(phox)-dependent reactive oxygen species (ROS) production contributed to MMP9 activation and collagen expression, which was suppressed by transfecting pcDNA3-Smad7 in cardiac fibroblasts. The effect of Smad7 overexpression on MMP9 activity and collagen expression was further reversed by adding H2O2 (10 μmol/L). In contrast, knockdown of Smad7 caused the enhanced collagen synthesis in cardiac fibroblasts, which was also reversed by treating cells with a ROS inhibitor, YCG063 (2 μmol/L). Further investigation showed that Smad7 regulated NADPH-mediated ROS production through activating Heme oxygenase-1 (HO-1). Meanwhile, the intercellular level of bilirubin (product of hemin) and nitric oxide (NO) in cell supernatant were not significantly increased in cells treated with AngII or transfected with Smad7. Knockdown of HO-1 in Smad7-overexpressed cardiac fibroblasts or cells pretreated with SnPP IX, a competitive inhibitor of HO-1 activity, resulted in increased productions of ROS and NADPH p47(phox), and abolished the inhibitory effects of Smad7 on MMP9 activity and collagen expression. Our results indicated that HO-1 might be critically involved in Smad7-mediated regulation of MMP9 activity and fibrogenic genes expression via antagonizing the enhanced myocardial oxidative stress.
authors: Department of Pathology, Taizhou People's Hospital, 210 Yingchun Road, Taizhou, 225300, Jiangsu, China. yuhongmiaomiao@163.com
authors: Hong
authors: H
authors: Yu
authors: Junxing
authors: J
authors: Huang
authors: Shijun
authors: S
authors: Wang
authors: Gang
authors: G
authors: Zhao
authors: Xia
authors: X
authors: Jiao
authors: Li
authors: L
authors: Zhu
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D003094:Collagen / Q000096:biosynthesis*; D017931:DNA Primers / Q000235:genetics; D005347:Fibroblasts; D051547:Heme Oxygenase-1 / Q000378:metabolism*; D006835:Hydrazones; D008156:Luciferases; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D009593:Nitroimidazoles; D010957:Plasmids / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D051906:Smad7 Protein / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D006835:Hydrazones; D009593:Nitroimidazoles; D017382:Reactive Oxygen Species; D051906:Smad7 Protein; C497808:Smad7 protein, rat; C555826:YCG 063; D003094:Collagen; D008156:Luciferases; D051547:Heme Oxygenase-1; D020780:Matrix Metalloproteinase 9; C572337:Mmp9 protein, rat
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