Tissue-type plasminogen activator deficiency exacerbates cholestatic liver injury in mice.
Recent studies demonstrating a role for plasminogen activator inhibitor (PAI)-1 in cholestatic liver disease in mice suggested that tissue-type plasminogen activator (tPA) or urokinase plasminogen activator (uPA) might be important after biliary tract obstruction. We now demonstrate that blocking tPA exacerbates liver injury after bile duct ligation (BDL). tPA deficient mice have increased bile infarcts, increased TUNEL positive cells, increased neutrophil infiltration, reduced hepatocyte proliferation and reduced ductular reaction 72 hours after BDL compared to wild type mice. In addition, the protective and proliferative effects of plasminogen activator inhibitor 1 (PAI-1) deficiency after BDL are dramatically blocked by the tPA inhibitor tPA-STOP. One potential mechanism for these effects is that both tPA deficiency and tPA-STOP reduce hepatocyte growth factor (HGF) activation and c-Met phosphorylation in the liver after BDL. In support of this hypothesis, HGF treatment reverses the effects of tPA deficiency in mice. Furthermore, preferential tPA activation in areas of injury after BDL might occur because fibrin accumulates in bile infarcts and activates tPA.


CONCLUSIONS
tPA inactivation accelerates liver injury after BDL and reduces HGF activation. These data suggest that strategies to increase HGF activation might be protective in liver diseases with biliary tract obstruction even without increased HGF production.
Wang
Hongtao
H
Division of Gastroenterology and Nutrition, Department of Pediatrics, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
Zhang
Yan
Y
Heuckeroth
Robert O
RO
D000818:Animals; D001652:Bile Ducts / Q000378:metabolism / Q000473:pathology; D016923:Cell Death / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D054360:Chemokine CXCL1; D054426:Chemokine CXCL2; D019743:Chemokines, CXC / Q000235:genetics; D001651:Cholestasis, Extrahepatic / Q000378:metabolism* / Q000473:pathology*; D004195:Disease Models, Animal; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D005337:Fibrin / Q000378:metabolism; D005341:Fibrinolysin / Q000378:metabolism; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism / Q000473:pathology; D007238:Infarction / Q000378:metabolism / Q000473:pathology; D008099:Liver / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009504:Neutrophils / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000172:deficiency* / Q000378:metabolism; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism
D054360:Chemokine CXCL1; D054426:Chemokine CXCL2; D019743:Chemokines, CXC; C513297:Cxcl1 protein, rat; C513296:Cxcl2 protein, rat; D012333:RNA, Messenger; D017228:Hepatocyte Growth Factor; D005337:Fibrin; D010959:Tissue Plasminogen Activator; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator