title: Fas-induced apoptosis increases hepatocyte tissue factor procoagulant activity in vitro and in vivo.
abstract: Hepatocyte (HPC) apoptosis occurs in association with hepatotoxic responses and chronic liver disease, and is coupled to activation of the blood coagulation cascade. HPCs have been shown to express tissue factor (TF), the primary activator of blood coagulation, in a form that lacks procoagulant activity. In this study, we determined the effect of inducing HPC apoptosis on the procoagulant activity of TF. Treatment of primary mouse HPCs with the Fas death receptor agonist (anti-CD95 antibody, Jo2) triggered apoptosis as shown by cleavage of caspase-3, increased caspase-3 proteolytic activity, and cell surface exposure of phosphatidylserine (PS). Jo2-induced apoptosis significantly increased TF-dependent factor Xa generation by HPCs. Moreover, Jo2 treatment was associated with increased levels of microparticle-associated TF procoagulant activity in the culture medium. Pretreatment with a caspase-3 inhibitor significantly reduced Jo2-induced HPC TF activity and prevented the increase in microparticle-associated TF procoagulant activity. Application of the high-affinity PS-binding protein lactadherin inhibited TF-dependent factor Xa generation by Jo2-treated HPCs and dramatically reduced microparticle-associated TF procoagulant activity. Treatment of wild-type mice with a sublethal dose of Jo2 was associated with a robust increase in the activation of coagulation as measured by plasma thrombin-antithrombin (TAT) levels; whereas mice with liver-specific TF deficiency had significantly lower TAT levels. Overall, the results indicate that Fas-initiated, caspase-3-dependent HPC apoptosis increases TF procoagulant activity through a mechanism involving PS externalization. This suggests that activation of liver TF likely contributes to the procoagulant state associated with HPC apoptosis in liver toxicity and disease.
authors.affiliation: Department of Pathobiology and Diagnostic Investigation, Michigan State University, 253 Food Safety and Toxicology Bldg, East Lansing, Michigan 48824 luyendyk@cvm.msu.edu.
authors.forename: Michelle
authors.initials: M
authors.lastname: Lopez
authors.affiliation: Department of Pathobiology and Diagnostic Investigation, Michigan State University, 253 Food Safety and Toxicology Bldg, East Lansing, Michigan 48824 luyendyk@cvm.msu.edu.
authors.forename: Anna K
authors.initials: AK
authors.lastname: Kopec
authors.affiliation: Department of Pharmacology and Toxicology, Michigan State University, B346 Life Sciences, Michigan State University, East Lansing, Michigan 48824.
authors.forename: Nikita
authors.initials: N
authors.lastname: Joshi
authors.affiliation: Department of Medicine, University of North Carolina at Chapel Hill, 98 Manning Dr. Chapel Hill, North Carolina 27599.
authors.forename: Julia E
authors.initials: JE
authors.lastname: Geddings
authors.affiliation: Department of Pathobiology and Diagnostic Investigation, Michigan State University, 253 Food Safety and Toxicology Bldg, East Lansing, Michigan 48824.
authors.forename: Holly
authors.initials: H
authors.lastname: Cline
authors.affiliation: Department of Pathobiology and Diagnostic Investigation, Michigan State University, 253 Food Safety and Toxicology Bldg, East Lansing, Michigan 48824.
authors.forename: Keara L
authors.initials: KL
authors.lastname: Towery
authors.affiliation: Department of Pharmacology and Toxicology, Michigan State University, B346 Life Sciences, Michigan State University, East Lansing, Michigan 48824.
authors.forename: Cheryl E
authors.initials: CE
authors.lastname: Rockwell
authors.affiliation: Department of Medicine, University of North Carolina at Chapel Hill, 98 Manning Dr. Chapel Hill, North Carolina 27599.
authors.forename: Nigel
authors.initials: N
authors.lastname: Mackman
authors.affiliation: Department of Pathobiology and Diagnostic Investigation, Michigan State University, 253 Food Safety and Toxicology Bldg, East Lansing, Michigan 48824 luyendyk@cvm.msu.edu.
authors.forename: James P
authors.initials: JP
authors.lastname: Luyendyk
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D000990:Antithrombin III / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D001777:Blood Coagulation / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D061945:Caspase Inhibitors / Q000494:pharmacology; D055252:Cell-Derived Microparticles / Q000378:metabolism; D002478:Cells, Cultured; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010447:Peptide Hydrolases / Q000378:metabolism; D010718:Phosphatidylserines / Q000378:metabolism; D015398:Signal Transduction; D013925:Thromboplastin / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D019014:fas Receptor / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*
chemical_list: D000906:Antibodies; D061945:Caspase Inhibitors; C491899:Fas protein, mouse; D010718:Phosphatidylserines; C046193:antithrombin III-protease complex; D019014:fas Receptor; D000990:Antithrombin III; D013925:Thromboplastin; D010447:Peptide Hydrolases; C505409:Casp3 protein, mouse; D053148:Caspase 3
keywords: apoptosis; coagulation; hepatotoxicity; microparticles; tissue factor