title: Mouse genetic background contributes to hepatocyte susceptibility to Fas-mediated apoptosis.
abstract: Liver disease progression is modulated by genetic modifiers in mouse strains and across human races and ethnicities. We hypothesized that hepatocyte culture duration and genetic background regulate hepatocyte susceptibility to apoptosis. Hepatocytes were isolated from FVB/N, C57BL/6, and C3H/He mice and cultured or treated with Fas ligand or acetaminophen after different culture times. Protein and mRNA expressions of Fas receptor, caspases-3/7/8, and Bak/Bax/Bid proteins were determined. FVB/N hepatocytes manifested rapid decreases of caspases-3/7 but not caspase-8 as culture time increased, which paralleled decreased susceptibility to apoptosis. Some changes were also found in Fas-receptor and Bak, Bax, and Bid proteins; caspase mRNA decreases were also noted. Caspase protein degradation was partially reversed by lysosomal protease but not proteasome or autophagy inhibitors. C57BL/6 and FVB/N hepatocytes behaved similarly in their limited susceptibility to apoptosis, whereas C3H/He hepatocytes show limited alterations in caspases, with consequent increased susceptibility to apoptosis. Similarly, C3H/He mice were more susceptible than C57BL/6 and FVB/N mice to Fas-mediated liver injury. Therefore there are significant mouse strain-dependent differences in susceptibility to apoptosis and selective loss of caspases upon short-term hepatocyte culture, with consequent decrease in susceptibility to apoptosis. These differences likely reflect genetic modifiers that provide resistance or predisposition to hepatocyte death.
authors.affiliation: Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109 sujith@umich.edu.
authors.forename: Sujith V W
authors.initials: SV
authors.lastname: Weerasinghe
authors.affiliation: Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109.
authors.forename: Min-Jung
authors.initials: MJ
authors.lastname: Park
authors.affiliation: Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Portney
authors.affiliation: Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109 Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109.
authors.forename: M Bishr
authors.initials: MB
authors.lastname: Omary
mesh_terms: D000082:Acetaminophen; D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D051023:BH3 Interacting Domain Death Agonist Protein / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D018929:Cell Culture Techniques; D053222:Fas Ligand Protein / Q000378:metabolism; D000068617:Genetic Background; D022781:Hepatocytes / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H / Q000235:genetics; D008810:Mice, Inbred C57BL / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D019014:fas Receptor / Q000235:genetics* / Q000378:metabolism*
chemical_list: D051023:BH3 Interacting Domain Death Agonist Protein; C494773:Bak1 protein, mouse; C494827:Bax protein, mouse; C494815:Bid protein, mouse; D053222:Fas Ligand Protein; C491899:Fas protein, mouse; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D019014:fas Receptor; D000082:Acetaminophen; C505409:Casp3 protein, mouse; C505524:Casp7 protein, mouse; C505526:Casp8 protein, mouse; D053148:Caspase 3; D053179:Caspase 7; D053181:Caspase 8