title: Norepinephrine enhances fibrosis mediated by TGF-beta in cardiac fibroblasts.
abstract: Cardiac fibrosis results from proliferation of interstitial fibroblasts and concomitant increased biosynthesis of extracellular matrix (ECM) components and is often complicated by cardiac hypertrophy. This study was conducted to investigate whether norepinephrine (NE) potentiates transforming growth factor-beta (TGF-beta)-induced cardiac fibrosis. The expression of the cardiac ECM proteins, plasminogen activator inhibitor-1 (PAI-1), fibronectin, and collagen type I, was examined by Western blotting using extracts from neonatal rat primary cardiac fibroblasts. In cardiac fibroblasts, treatment with a combination of NE and TGF-beta1 increased cell proliferation and ECM expression. Luciferase assays were conducted to clarify the effect of NE on TGF-beta signaling. TGF-beta1 (1 ng/mL) increased the specific signaling activity 2-fold, whereas the combination of NE (10 micro mol/L) and TGF-beta1 (1 ng/mL) resulted in an approximate 10-fold increase in specific signaling activity. We confirmed that treatment with NE markedly enhances TGF-beta-induced phosphorylation of activating transcription factor 2 (ATF-2). These results indicated that NE has a synergistic effect on TGF-beta signaling. To determine whether this activation by NE was mediated by the TGF-beta1 receptor, we used a dominant negative vector of the TGF-beta1 type II receptor, and the synergistic effects were inhibited. Furthermore, this synergistic effect was attenuated by a specific inhibitor of p38, SB203680. These data indicate that NE enhances cardiac fibrosis through TGF-beta1 post-receptor signaling, predominantly via the p38 MAP kinase pathway.
authors.affiliation: Department of Cardiovascular Medicine, Atomic Bomb Disease Institute, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Akiyama-Uchida
authors.forename: Naoto
authors.initials: N
authors.lastname: Ashizawa
authors.forename: Akira
authors.initials: A
authors.lastname: Ohtsuru
authors.forename: Shinji
authors.initials: S
authors.lastname: Seto
authors.forename: Tomoo
authors.initials: T
authors.lastname: Tsukazaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kikuchi
authors.forename: Shunichi
authors.initials: S
authors.lastname: Yamashita
authors.forename: Katsusuke
authors.initials: K
authors.lastname: Yano
mesh_terms: D051698:Activating Transcription Factor 2; D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects; D024042:Collagen Type I / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004357:Drug Synergism; D005260:Female; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005353:Fibronectins / Q000378:metabolism; D005355:Fibrosis; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D009543:Nifedipine / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology*; D010766:Phosphorylation; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism; D011247:Pregnancy; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1; D014407:Tumor Cells, Cultured
chemical_list: C497105:ATF2 protein, human; D051698:Activating Transcription Factor 2; C497107:Atf2 protein, rat; D024042:Collagen Type I; D017362:Cyclic AMP Response Element-Binding Protein; D005353:Fibronectins; D005419:Flavonoids; D007093:Imidazoles; D017395:Plasminogen Activator Inhibitor 1; D011725:Pyridines; D011993:Recombinant Fusion Proteins; C508960:TGFB1 protein, human; C508962:Tgfb1 protein, rat; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D008156:Luciferases; D009543:Nifedipine; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D009638:Norepinephrine