title: Sulforaphane attenuates hepatic fibrosis via NF-E2-related factor 2-mediated inhibition of transforming growth factor-β/Smad signaling.
abstract: Sulforaphane (SFN) is a dietary isothiocyanate that exerts chemopreventive effects via NF-E2-related factor 2 (Nrf2)-mediated induction of antioxidant/phase II enzymes, such as heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1). This work was undertaken to evaluate the effects of SFN on hepatic fibrosis and profibrotic transforming growth factor (TGF)-β/Smad signaling, which are closely associated with oxidative stress. SFN suppressed TGF-β-enhanced expression of α-smooth muscle actin (α-SMA), a marker of hepatic stellate cell (HSC) activation, and profibrogenic genes such as type I collagen, fibronectin, tissue inhibitor of matrix metalloproteinase (TIMP)-1, and plasminogen activator inhibitor (PAI)-1 in hTERT, an immortalized human HSC line. SFN inhibited TGF-β-stimulated activity of a PAI-1 promoter construct and (CAGA)(9) MLP-Luc, an artificial Smad3/4-specific reporter, in addition to reducing phosphorylation and nuclear translocation of Smad3. Nrf2 overexpression was sufficient to inhibit the TGF-β/Smad signaling and PAI-1 expression. Conversely, knockdown of Nrf2, but not inhibition of HO-1 or NQO1 activity, significantly abolished the inhibitory effect of SFN on (CAGA)(9) MLP-Luc activity. However, inhibition of NQO1 activity reversed repression of TGF-β-stimulated expression of type I collagen by SFN, suggesting the involvement of antioxidant activity of SFN in the suppression of Smad-independent fibrogenic gene expression. Finally, SFN treatment attenuated the development and progression of early stage hepatic fibrosis induced by bile duct ligation in mice, accompanied by reduced expression of type I collagen and α-SMA. Collectively, these results show that SFN elicits an antifibrotic effect on hepatic fibrosis through Nrf2-mediated inhibition of the TGF-β/Smad signaling and subsequent suppression of HSC activation and fibrogenic gene expression.
authors.affiliation: Department of Internal Medicine and Department of Biochemistry and Cell Biology, Research Institute of Aging and Metabolism, WCU Program, Kyungpook National University School of Medicine, Daegu 700-721, Republic of Korea.
authors.forename: Chang Joo
authors.initials: CJ
authors.lastname: Oh
authors.affiliation: Department of Internal Medicine and Department of Biochemistry and Cell Biology, Research Institute of Aging and Metabolism, WCU Program, Kyungpook National University School of Medicine, Daegu 700-721, Republic of Korea.
authors.forename: Joon-Young
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine and Department of Biochemistry and Cell Biology, Research Institute of Aging and Metabolism, WCU Program, Kyungpook National University School of Medicine, Daegu 700-721, Republic of Korea.
authors.forename: Ae-Kyung
authors.initials: AK
authors.lastname: Min
authors.affiliation: Department of Internal Medicine and Department of Biochemistry and Cell Biology, Research Institute of Aging and Metabolism, WCU Program, Kyungpook National University School of Medicine, Daegu 700-721, Republic of Korea.
authors.forename: Keun-Gyu
authors.initials: KG
authors.lastname: Park
authors.affiliation: Department of Internal Medicine and Department of Biochemistry and Cell Biology, Research Institute of Aging and Metabolism, WCU Program, Kyungpook National University School of Medicine, Daegu 700-721, Republic of Korea; Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202-5122, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Harris
authors.affiliation: Department of Internal Medicine and Department of Biochemistry and Cell Biology, Research Institute of Aging and Metabolism, WCU Program, Kyungpook National University School of Medicine, Daegu 700-721, Republic of Korea. Electronic address: jongikim@hotmail.com.
authors.forename: Han-Jong
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine and Department of Biochemistry and Cell Biology, Research Institute of Aging and Metabolism, WCU Program, Kyungpook National University School of Medicine, Daegu 700-721, Republic of Korea. Electronic address: leei@knu.ac.kr.
authors.forename: In-Kyu
authors.initials: IK
authors.lastname: Lee
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D002460:Cell Line; D004790:Enzyme Induction / Q000187:drug effects; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D005355:Fibrosis; D015870:Gene Expression / Q000187:drug effects; D017930:Genes, Reporter; D006801:Humans; D017879:Isothiocyanates; D008107:Liver Diseases / Q000473:pathology / Q000517:prevention & control*; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D058258:Serpin E2 / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D051785:Smad Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013454:Sulfoxides; D013861:Thiocyanates / Q000494:pharmacology* / Q000627:therapeutic use; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D016326:Extracellular Matrix Proteins; D017879:Isothiocyanates; D051267:NF-E2-Related Factor 2; D058258:Serpin E2; C511869:Serpine2 protein, mouse; D051785:Smad Proteins; D013454:Sulfoxides; D013861:Thiocyanates; D016212:Transforming Growth Factor beta; D008156:Luciferases; C016766:sulforaphane