title: The β-adrenoceptor agonist isoproterenol rescues acetaminophen-injured livers through increasing progenitor numbers by Wnt in mice.
abstract: Acetaminophen (APAP)-induced acute liver injury (AILI) is a major health problem. Accumulating evidence suggests that the sympathetic nervous system (SNS) regulates neuronal and hematopoietic progenitors. SNS signaling affects hepatic progenitor/oval cells (HPCs) and β-adrenoceptor agonism will expand HPCs to reduce AILI. Dopamine β-hydroxylase-deficient mice (Dbh-/-), lacking catecholamine SNS neurotransmitters, isolated HPCs, and immature ductular 603B cells were initially used to investigate SNS involvement in HPC physiology. Subsequently, control mice were treated with APAP (350 mg/kg) followed by the β-adrenoceptor agonist, isoproterenol (ISO), or the β-adrenoceptor antagonist, propranolol. Mechanistic studies examined effects of non-SNS HPC expansion on AILI, involvement of the canonical Wnt/β-catenin pathway (CWP) in the action of ISO on HPC expansion and comparison of ISO with the current standard of care, N-acetylcysteine (NAC). Dbh-/- mice lacking catecholamines had low HPC numbers, reconstituted by ISO. In vitro, ISO-induced proliferation of 603B cells was CWP dependent. In control mice, AILI raised HPC numbers, further increased by ISO, with attenuation of liver injury. Delayed administration of NAC did not, but delayed ISO did, reverse AILI. Propranolol worsened AILI. AILI activated the CWP, and ISO enhanced Wnt-ligand production. HPCs were the major source of Wnt ligands. Recombinant Wnt3a and ISO-603B-conditioned media, but not ISO alone, protected isolated hepatocytes from death, reversed by DKK1-a Wnt antagonist. Additionally, tumor-associated weak inducer of apoptosis expanded HPCs and protected against AILI. Furthermore, allotransplantation of HPCs from APAP+ISO-treated mice to other APAP-injured mice improved AILI, an effect antagonized by DKK1.
  
  
  CONCLUSIONS
  SNS catecholamines expand HPCs, which are both targets and sources of Wnt ligands. Hepatoprotection by ISO is mediated by para- and autocrine effects of Wnt signaling. ISO represents novel pharmacotherapy for AILI.
authors.affiliation: Institute for Liver and Digestive Health, University College London, London, United Kingdom.
authors.forename: Junpei
authors.initials: J
authors.lastname: Soeda
authors.forename: Angelina
authors.initials: A
authors.lastname: Mouralidarane
authors.forename: Shuvra
authors.initials: S
authors.lastname: Ray
authors.forename: Marco
authors.initials: M
authors.lastname: Novelli
authors.forename: Steven
authors.initials: S
authors.lastname: Thomas
authors.forename: Tania
authors.initials: T
authors.lastname: Roskams
authors.forename: Anna Mae
authors.initials: AM
authors.lastname: Diehl
authors.forename: Jude A
authors.initials: JA
authors.lastname: Oben
mesh_terms: D000082:Acetaminophen / Q000506:poisoning; D000318:Adrenergic beta-Agonists / Q000494:pharmacology / Q000627:therapeutic use*; D018712:Analgesics, Non-Narcotic / Q000506:poisoning; D000818:Animals; D002460:Cell Line; D056486:Chemical and Drug Induced Liver Injury / Q000188:drug therapy* / Q000209:etiology; D004353:Drug Evaluation, Preclinical; D007545:Isoproterenol / Q000494:pharmacology / Q000627:therapeutic use*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D013234:Stem Cells / Q000378:metabolism / Q000473:pathology; D013564:Sympathetic Nervous System / Q000187:drug effects; D051153:Wnt Proteins / Q000378:metabolism*
chemical_list: D000318:Adrenergic beta-Agonists; D018712:Analgesics, Non-Narcotic; D051153:Wnt Proteins; D000082:Acetaminophen; D007545:Isoproterenol