title: Metformin attenuates lung fibrosis development via NOX4 suppression.
abstract: Accumulation of profibrotic myofibroblasts in fibroblastic foci (FF) is a crucial process for development of fibrosis during idiopathic pulmonary fibrosis (IPF) pathogenesis, and transforming growth factor (TGF)-β plays a key regulatory role in myofibroblast differentiation. Reactive oxygen species (ROS) has been proposed to be involved in the mechanism for TGF-β-induced myofibroblast differentiation. Metformin is a biguanide antidiabetic medication and its pharmacological action is mediated through the activation of AMP-activated protein kinase (AMPK), which regulates not only energy homeostasis but also stress responses, including ROS. Therefore, we sought to investigate the inhibitory role of metformin in lung fibrosis development via modulating TGF-β signaling.
  
  
  
  TGF-β-induced myofibroblast differentiation in lung fibroblasts (LF) was used for in vitro models. The anti-fibrotic role of metfromin was examined in a bleomycin (BLM)-induced lung fibrosis model.
  
  
  
  We found that TGF-β-induced myofibroblast differentiation was clearly inhibited by metformin treatment in LF. Metformin-mediated activation of AMPK was responsible for inhibiting TGF-β-induced NOX4 expression. NOX4 knockdown and N-acetylcysteine (NAC) treatment illustrated that NOX4-derived ROS generation was critical for TGF-β-induced SMAD phosphorylation and myofibroblast differentiation. BLM treatment induced development of lung fibrosis with concomitantly enhanced NOX4 expression and SMAD phosphorylation, which was efficiently inhibited by metformin. Increased NOX4 expression levels were also observed in FF of IPF lungs and LF isolated from IPF patients.
  
  
  
  These findings suggest that metformin can be a promising anti-fibrotic modality of treatment for IPF affected by TGF-β.
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.|Department of Respiratory Medicine, Faculty of Life Science, Kumamoto University, Kumamoto, Japan.
authors: Nahoko
authors: N
authors: Sato
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Naoki
authors: N
authors: Takasaka
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Masahiro
authors: M
authors: Yoshida
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.|Research Institute for Diseases of the Chest, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors: Kazuya
authors: K
authors: Tsubouchi
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Shunsuke
authors: S
authors: Minagawa
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan. araya@jikei.ac.jp.
authors: Jun
authors: J
authors: Araya
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Nayuta
authors: N
authors: Saito
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Yu
authors: Y
authors: Fujita
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Yusuke
authors: Y
authors: Kurita
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Kenji
authors: K
authors: Kobayashi
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Saburo
authors: S
authors: Ito
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Hiromichi
authors: H
authors: Hara
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Tsukasa
authors: T
authors: Kadota
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Haruhiko
authors: H
authors: Yanagisawa
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Mitsuo
authors: M
authors: Hashimoto
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Hirofumi
authors: H
authors: Utsumi
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Hiroshi
authors: H
authors: Wakui
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Jun
authors: J
authors: Kojima
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Takanori
authors: T
authors: Numata
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Yumi
authors: Y
authors: Kaneko
authors: Division of Chest Diseases; Department of Surgery, Jikei University School of Medicine, Tokyo, Japan.
authors: Makoto
authors: M
authors: Odaka
authors: Division of Chest Diseases; Department of Surgery, Jikei University School of Medicine, Tokyo, Japan.
authors: Toshiaki
authors: T
authors: Morikawa
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Katsutoshi
authors: K
authors: Nakayama
authors: Department of Respiratory Medicine, Faculty of Life Science, Kumamoto University, Kumamoto, Japan.
authors: Hirotsugu
authors: H
authors: Kohrogi
authors: Division of Respiratory Diseases; Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
authors: Kazuyoshi
authors: K
authors: Kuwano
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000818:Animals; D001761:Bleomycin; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D019610:Cytoprotection; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000201:enzymology / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D008168:Lung / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008687:Metformin / Q000494:pharmacology*; D008810:Mice, Inbred C57BL; D058628:Myofibroblasts / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D000074663:NADPH Oxidase 4 / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000378:metabolism; D051785:Smad Proteins / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000494:pharmacology
chemical_list: D017382:Reactive Oxygen Species; D051785:Smad Proteins; D016212:Transforming Growth Factor beta; D001761:Bleomycin; D008687:Metformin; D000074663:NADPH Oxidase 4; C498910:NOX4 protein, human; C422943:Nox4 protein, mouse; D055372:AMP-Activated Protein Kinases
keywords: IPF; Metformin; NOX4; ROS; TGF-β