title: Interaction of ERK1/2 and Smad2/3 signaling pathways in TGF-β1-induced TIMP-3 expression in rat chondrocytes.
abstract: Tissue inhibitor of metalloproteinase-3 (TIMP-3) is an important natural inhibitor of matrix metalloproteinases (MMPs) and of a disintegrin and metalloproteinase with thrombospondin motif (ADAMTs), which can cleave cartilage extracellular matrix components to cause cartilage degradation. In this study, our data suggest TGF-β1 induces TIMP-3 expression through activations of both the ERK1/2 and Smad2/3 signaling pathways. TGF-β1-stimulated TIMP-3 expression was significantly inhibited by SB525334 (TGF-β receptor I kinase inhibitor), accompanied by a reduction in ERK1/2 and Smad3 phosphorylation. We used PD98059 (MEK inhibitor) and SIS3 (inhibitor of Smad3 phosphorylation) to investigate the respective roles of ERK1/2 and Smad2/3 signaling pathways in TGF-β1-induced TIMP-3 expression. The results show PD98059 treatment significantly suppressed TGF-β1-induced ERK1/2 phosphorylation and TIMP-3 expression. Under these conditions, the degree of Smad3 phosphorylation correlated with ERK1/2 activation, which suggests that ERK1/2 may activate Smad3 phosphorylation. SIS3 significantly inhibited TGF-β1-induced Smad3 phosphorylation and TIMP-3 expression. ERK1/2 phosphorylation alone had no effect on TGF-β1-induced TIMP-3 expression, which suggests ERK1/2 via Smad3 phosphorylation regulates TGF-β1-induced TIMP-3 expression. Here, we demonstrate that ERK1/2 may be capable of activating the Smad2/3 signaling pathway to result in TGF-β1-induced TIMP-3 up-regulation.
authors.affiliation: Department of Orthopaedics, Shanghai 3rd People's Hospital, School of Medicine, Shanghai Jiao Tong University, 280 Mohe Road, Shanghai, China; Department of Orthopaedics, The No. 6 Affiliated Hospital of Shanghai Jiaotong University, 600 Yishan Road, Shanghai, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Orthopaedics, Shanghai 3rd People's Hospital, School of Medicine, Shanghai Jiao Tong University, 280 Mohe Road, Shanghai, China.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of Orthopaedics, Shanghai 3rd People's Hospital, School of Medicine, Shanghai Jiao Tong University, 280 Mohe Road, Shanghai, China.
authors.forename: Hairong
authors.initials: H
authors.lastname: Tao
authors.affiliation: Department of Orthopaedics, Shanghai 3rd People's Hospital, School of Medicine, Shanghai Jiao Tong University, 280 Mohe Road, Shanghai, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Jin
authors.affiliation: Department of Orthopaedics, Shanghai 3rd People's Hospital, School of Medicine, Shanghai Jiao Tong University, 280 Mohe Road, Shanghai, China.
authors.forename: Yonzhang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Orthopaedics, Shanghai 3rd People's Hospital, School of Medicine, Shanghai Jiao Tong University, 280 Mohe Road, Shanghai, China.
authors.forename: Xiongwei
authors.initials: X
authors.lastname: Lu
authors.affiliation: Department of Orthopaedics, Shanghai 3rd People's Hospital, School of Medicine, Shanghai Jiao Tong University, 280 Mohe Road, Shanghai, China.
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Hu
authors.affiliation: Department of Orthopaedics, The No. 6 Affiliated Hospital of Shanghai Jiaotong University, 600 Yishan Road, Shanghai, China. Electronic address: fancunyi888@yeah.net.
authors.forename: Cunyi
authors.initials: C
authors.lastname: Fan
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D005419:Flavonoids / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D051899:Smad2 Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051900:Smad3 Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000096:biosynthesis* / Q000235:genetics; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology*
chemical_list: C508504:6,7-dimethyl-2-(2E)-3-(1-methyl-2-phenyl-1H-pyrrolo(2,3-b)pyridin-3-yl-prop-2-enoyl)-1,2,3,4-tetrahydroisoquinoline hydrochloride; C521813:6-(2-tert-butyl-5-(6-methylpyridin-2-yl)-1H-imidazol-4-yl)quinoxaline; D005419:Flavonoids; D007093:Imidazoles; D007546:Isoquinolines; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D011758:Pyrroles; D011810:Quinoxalines; D051899:Smad2 Protein; C497784:Smad2 protein, rat; D051900:Smad3 Protein; C497787:Smad3 protein, rat; C508962:Tgfb1 protein, rat; D019717:Tissue Inhibitor of Metalloproteinase-3; D053773:Transforming Growth Factor beta1; D048052:Mitogen-Activated Protein Kinase 3; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one
keywords: Chondrocytes; ERK1/2; Smad2/3; TIMP-3; Transforming growth factor beta1