title: Osteopontin is a proximal effector of leptin-mediated non-alcoholic steatohepatitis (NASH) fibrosis.
abstract: Liver fibrosis develops when hepatic stellate cells (HSC) are activated into collagen-producing myofibroblasts. In non-alcoholic steatohepatitis (NASH), the adipokine leptin is upregulated, and promotes liver fibrosis by directly activating HSC via the hedgehog pathway. We reported that hedgehog-regulated osteopontin (OPN) plays a key role in promoting liver fibrosis. Herein, we evaluated if OPN mediates leptin-profibrogenic effects in NASH.
  
  
  
  Leptin-deficient (ob/ob) and wild-type (WT) mice were fed control or methionine-choline deficient (MCD) diet. Liver tissues were assessed by Sirius-red, OPN and αSMA IHC, and qRT-PCR for fibrogenic genes. In vitro, HSC with stable OPN (or control) knockdown were treated with recombinant (r)leptin and OPN-neutralizing or sham-aptamers. HSC response to OPN loss was assessed by wound healing assay. OPN-aptamers were also added to precision-cut liver slices (PCLS), and administered to MCD-fed WT (leptin-intact) mice to determine if OPN neutralization abrogated fibrogenesis.
  
  
  
  MCD-fed WT mice developed NASH-fibrosis, upregulated OPN, and accumulated αSMA+ cells. Conversely, MCD-fed ob/ob mice developed less fibrosis and accumulated fewer αSMA+ and OPN+ cells. In vitro, leptin-treated HSC upregulated OPN, αSMA, collagen 1α1 and TGFβ mRNA by nearly 3-fold, but this effect was blunted by OPN loss. Inhibition of PI3K and transduction of dominant negative-Akt abrogated leptin-mediated OPN induction, while constitutive active-Akt upregulated OPN. Finally, OPN neutralization reduced leptin-mediated fibrogenesis in both PCLS and MCD-fed mice.
  
  
  
  OPN overexpression in NASH enhances leptin-mediated fibrogenesis via PI3K/Akt. OPN neutralization significantly reduces NASH fibrosis, reinforcing the potential utility of targeting OPN in the treatment of patients with advanced NASH.
authors.affiliation: Regeneration and Repair Group, The Institute of Hepatology, Foundation for Liver Research, London, UK; Division of Transplantation Immunology and Mucosal Biology, King's College London, UK.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Coombes
authors.affiliation: Division of Gastroenterology, Department of Medicine, Duke University, NC, USA; Section of Gastroenterology, Department of Medicine, Durham Veteran Affairs Medical Center, Durham, NC, USA.
authors.forename: Steve S
authors.initials: SS
authors.lastname: Choi
authors.affiliation: Division of Gastroenterology, Department of Medicine, Duke University, NC, USA.
authors.forename: Marzena
authors.initials: M
authors.lastname: Swiderska-Syn
authors.affiliation: Regeneration and Repair Group, The Institute of Hepatology, Foundation for Liver Research, London, UK; Department of Gastroenterology and Hepatology, Essen University Hospital, Essen, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Manka
authors.affiliation: Snyder Institute for Chronic Diseases, Health Research and Innovation Centre (HRIC), University of Calgary, Canada.
authors.forename: Danielle T
authors.initials: DT
authors.lastname: Reid
authors.affiliation: Division of Transplantation Immunology and Mucosal Biology, King's College London, UK; Viral Hepatitis and Alcohol Research Group, The Institute of Hepatology, Foundation for Liver Research, London, UK.
authors.forename: Elena
authors.initials: E
authors.lastname: Palma
authors.affiliation: Regeneration and Repair Group, The Institute of Hepatology, Foundation for Liver Research, London, UK; Division of Transplantation Immunology and Mucosal Biology, King's College London, UK.
authors.forename: Marco A
authors.initials: MA
authors.lastname: Briones-Orta
authors.affiliation: Division of Gastroenterology, Department of Medicine, Duke University, NC, USA.
authors.forename: Guanhua
authors.initials: G
authors.lastname: Xie
authors.affiliation: Regeneration and Repair Group, The Institute of Hepatology, Foundation for Liver Research, London, UK.
authors.forename: Rasha
authors.initials: R
authors.lastname: Younis
authors.affiliation: Regeneration and Repair Group, The Institute of Hepatology, Foundation for Liver Research, London, UK.
authors.forename: Naoto
authors.initials: N
authors.lastname: Kitamura
authors.affiliation: Viral Hepatitis and Alcohol Research Group, The Institute of Hepatology, Foundation for Liver Research, London, UK.
authors.forename: Marco
authors.initials: M
authors.lastname: Della Peruta
authors.affiliation: Liver Cell Biology Lab (LIVR), Department of Cell Biology (CYTO), Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Shanna
authors.initials: S
authors.lastname: Bitencourt
authors.affiliation: Liver Cell Biology Lab (LIVR), Department of Cell Biology (CYTO), Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Laurent
authors.initials: L
authors.lastname: Dollé
authors.affiliation: Centre for Liver Research and NIHR Birmingham Biomedical Research Unit, University of Birmingham, Birmingham, UK.
authors.forename: Ye Htun
authors.initials: YH
authors.lastname: Oo
authors.affiliation: Department of Surgery, Loyola University, Chicago, USA.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Mi
authors.affiliation: Department of Surgery, Loyola University, Chicago, USA.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Kuo
authors.affiliation: Regeneration and Repair Group, The Institute of Hepatology, Foundation for Liver Research, London, UK; Division of Transplantation Immunology and Mucosal Biology, King's College London, UK.
authors.forename: Roger
authors.initials: R
authors.lastname: Williams
authors.affiliation: Division of Transplantation Immunology and Mucosal Biology, King's College London, UK; Viral Hepatitis and Alcohol Research Group, The Institute of Hepatology, Foundation for Liver Research, London, UK.
authors.forename: Shilpa
authors.initials: S
authors.lastname: Chokshi
authors.affiliation: Department of Gastroenterology and Hepatology, Essen University Hospital, Essen, Germany.
authors.forename: Ali
authors.initials: A
authors.lastname: Canbay
authors.affiliation: Liver Unit, St James University Hospital, Leeds, UK.
authors.forename: Lee C
authors.initials: LC
authors.lastname: Claridge
authors.affiliation: Snyder Institute for Chronic Diseases, Health Research and Innovation Centre (HRIC), University of Calgary, Canada.
authors.forename: Bertus
authors.initials: B
authors.lastname: Eksteen
authors.affiliation: Division of Gastroenterology, Department of Medicine, Duke University, NC, USA.
authors.forename: Anna Mae
authors.initials: AM
authors.lastname: Diehl
authors.affiliation: Regeneration and Repair Group, The Institute of Hepatology, Foundation for Liver Research, London, UK; Division of Transplantation Immunology and Mucosal Biology, King's College London, UK; Department of Surgery, Loyola University, Chicago, USA; Liver Unit, Barts Health NHS Trust, London, UK; Department of Physiology, University of the Basque Country, Bilbao, Spain. Electronic address: wsyn@doctors.org.uk.
authors.forename: Wing-Kin
authors.initials: WK
authors.lastname: Syn
mesh_terms: D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D017353:Gene Deletion; D022781:Hepatocytes / Q000378:metabolism / Q000473:pathology; D020738:Leptin / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000378:metabolism / Q000473:pathology*; D008103:Liver Cirrhosis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008810:Mice, Inbred C57BL; D065626:Non-alcoholic Fatty Liver Disease / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D053495:Osteopontin / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D015854:Up-Regulation
chemical_list: D020738:Leptin; D053495:Osteopontin; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt
keywords: Adipokine; Fibrosis; Hepatic; Signaling