title: Extracellular-signal regulated kinase (Erk1/2), mitogen-activated protein kinase-activated protein kinase 2 (MK2) and tristetraprolin (TTP) comprehensively regulate injury-induced immediate early gene (IEG) response in in vitro liver organ culture.
abstract: Differentiated hepatocytes are long-lived and normally do not undergo cell division, however they have the unique capacity to autonomously decide their replication fate after liver injury. In this context, the key players of liver regeneration immediately after injury have not been adequately studied. Using an in vitro liver culture system, we show that after liver injury, p38 mitogen-activated protein kinase (p38MAPK), mitogen-activated protein kinase-activated protein kinase 2 (MK2) and extracellular-signal regulated kinase (Erk)1/2 were activated within 15 min and continued to be phosphorylated for more than 2h. Both p38MAPK and Erk1/2 were activated at the edge of the cut as well as on the liver surface where the mesothelial cell sheet expresses several cytokines. Notably, in human liver Erk1/2 was also activated under the mesothelial cell sheet shortly after liver resections. Furthermore, in in vitro liver slice culture immediate early genes (IEGs) were upregulated within 1-2 h and the S phase marker proliferation-cell-nuclear-antigen (PCNA) appeared 24 h after injury. Although Erk1/2 was activated after injury, in MK2 depleted liver a set of IEGs, such as Dusp1, Cox2, or c-Myc and proliferation marker gene Ki67 were not induced. In addition, in immortalized hepatocyte cells, THLE-2, the same subset of genes was upregulated upon stimulation with lipopolysaccharide (LPS), but not in the presence of MK2 inhibitor. The protein level of tristetraprolin (TTP), a substrate for MK2 that plays a role in mRNA degradation, was increased in the presence of MK2 inhibitor. In this context, the depletion of TTP gene rescued Dusp1, Cox2, or c-Myc upregulation in the presence of MK2 inhibitor. These data imply that MK2 pathway is positively involved in Erk1/2 induced IEG response after liver injury. These data also suggest that in vitro liver culture may be a useful tool for measuring the proliferation potential of hepatocytes in individual liver.
authors.affiliation: Institut fuer Biochemie, OE4310, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, D-30623 Hannover, Germany.
authors.forename: Doan Duy Hai
authors.initials: DDH
authors.lastname: Tran
authors.affiliation: Institut fuer Biochemie, OE4310, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, D-30623 Hannover, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Koch
authors.affiliation: Institut fuer Biochemie, OE4310, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, D-30623 Hannover, Germany.
authors.forename: Shashank
authors.initials: S
authors.lastname: Saran
authors.affiliation: Institut fuer Biochemie, OE4310, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, D-30623 Hannover, Germany.
authors.forename: Marcel
authors.initials: M
authors.lastname: Armbrecht
authors.affiliation: Department of Hepatobiliary and Transplant Surgery, University Medical Center Eppendorf, Martinistrasse 52, 20256, Hamburg, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Ewald
authors.affiliation: Department of Hepatobiliary and Transplant Surgery, University Medical Center Eppendorf, Martinistrasse 52, 20256, Hamburg, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Koch
authors.affiliation: Model Systems for Infection and Immunity (MSYS), Helmholtz Centre for Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany.
authors.forename: Tom
authors.initials: T
authors.lastname: Wahlicht
authors.affiliation: Model Systems for Infection and Immunity (MSYS), Helmholtz Centre for Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany.
authors.forename: Dagmar
authors.initials: D
authors.lastname: Wirth
authors.affiliation: Fraunhofer Institut für Toxikologie und Experimentelle Medizin Atemwegspharmakologie, Nikolai-Fuchs-Str.1, D-30625 Hannover, Germany.
authors.forename: Armin
authors.initials: A
authors.lastname: Braun
authors.affiliation: Department of Hepatobiliary and Transplant Surgery, University Medical Center Eppendorf, Martinistrasse 52, 20256, Hamburg, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Nashan
authors.affiliation: Institut fuer Biochemie, OE4310, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, D-30623 Hannover, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Gaestel
authors.affiliation: Institut fuer Biochemie, OE4310, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, D-30623 Hannover, Germany. Electronic address: Tamura.Teruko@MH-Hannover.de.
authors.forename: Teruko
authors.initials: T
authors.lastname: Tamura
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D017781:Genes, Immediate-Early; D022781:Hepatocytes / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D008099:Liver / Q000201:enzymology / Q000293:injuries / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009924:Organ Culture Techniques; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D015533:Transcriptional Activation; D059467:Transcriptome; D051816:Tristetraprolin / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D000099190:MAP-Kinase-Activated Kinase 2
chemical_list: D048049:Extracellular Signal-Regulated MAP Kinases; D047908:Intracellular Signaling Peptides and Proteins; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D018809:Proliferating Cell Nuclear Antigen; D017346:Protein Serine-Threonine Kinases; D051816:Tristetraprolin; D048051:p38 Mitogen-Activated Protein Kinases; D000099190:MAP-Kinase-Activated Kinase 2
keywords: Hepatocyte proliferation; Immediate early gene response; In vitro liver culture; Liver regeneration; MK2; TTP