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Updated: Jul 6, 2026
A Mouse Model of Chronic Liver Fibrosis for the Study of Biliary Atresia
Published on: February 3, 2023
Temporal-spatial activation of apoptosis and epithelial injury in murine experimental biliary atresia
Nissa Erickson1, Sujit Kumar Mohanty, Pranavkumar Shivakumar
1Cincinnati Children's Hospital Medical Center and Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229-3039, USA.
Insights
Biliary atresia involves early apoptosis of the biliary epithelium in a mouse model. Combined interferon-gamma and tumor necrosis factor-alpha synergistically activate caspases, driving this cell death and injury.
Area of Science:
- Hepatology
- Pediatric Gastroenterology
- Cell Biology
Background:
- Biliary atresia is a serious infant liver disease causing bile duct obstruction.
- Its exact cause is unknown, but increased pro-apoptosis molecules are observed.
- Apoptosis (programmed cell death) is hypothesized as a key injury mechanism.
Purpose of the Study:
- To investigate the role of apoptosis in the pathogenesis of experimental biliary atresia.
- To examine the molecular mechanisms, including cytokine signaling and caspase activation, involved in biliary epithelial injury.
Main Methods:
- Utilized a mouse model of biliary atresia induced by Rhesus rotavirus (RRV) infection.
- Quantified apoptosis using TUNEL and active caspase-3 staining in liver and bile duct tissues.
- Assessed gene expression of inflammatory cytokines and caspases.
- Investigated cholangiocyte viability and caspase activation in vitro with interferon-gamma (IFNγ) and tumor necrosis factor-alpha (TNFα).
- Evaluated the effect of a caspase inhibitor (IDN-8050) on apoptosis and injury in vivo.
Main Results:
- RRV infection significantly increased apoptosis in the biliary epithelium.
- Apoptosis peaked 5-10 days post-infection.
- Biliary expression of caspases 1 and 4, IFNγ, and TNFα genes increased.
- Co-exposure to IFNγ and TNFα, but not alone, induced caspase-3 activation and reduced cholangiocyte viability.
- Caspase inhibition reduced apoptosis and epithelial injury in the RRV model.
Conclusions:
- The biliary epithelium shows early apoptosis activation in this mouse model of biliary atresia.
- IFNγ and TNFα synergistically promote apoptosis in cholangiocytes via caspase-3 activation.
- Pharmacologic inhibition of caspases mitigates apoptosis and injury, supporting apoptosis's significant role in biliary atresia pathogenesis.
Unlabelled:
Biliary atresia is a fibro-inflammatory cholangiopathy that obstructs the extrahepatic bile ducts in young infants. Although the pathogenesis of the disease is undefined, studies in livers from affected children and neonatal mice with experimental biliary atresia have shown increased expression of proapoptosis molecules. Therefore, we hypothesized that apoptosis is a significant mechanism of injury to duct epithelium. To test this hypothesis, we quantified apoptosis using terminal transferase dUTP nick end labeling and active caspase-3 staining in livers and extrahepatic bile ducts from Balb/c mice infected with Rhesus rotavirus (RRV) within 24 hours of birth. RRV induced a significant increase in labeled cells in the portal tracts and in epithelial and subepithelial compartments of extrahepatic bile ducts, with onset within 3 days and peaks at 5-10 days. Exploring mechanisms of injury, we found increased biliary expression of caspases 1 and 4 and of interferon-gamma (IFNgamma)-related and tumor necrosis factor-alpha (TNFalpha)-related genes. Using a cholangiocyte cell line, we found that neither IFNgamma nor TNFalpha alone affected cell viability; however, simultaneous exposure to IFNgamma and TNFalpha activated caspase-3 and decreased cell viability. Inhibition of caspase activity blocked apoptosis and restored viability to cultured cholangiocytes. In vivo, administration of the caspase inhibitor IDN-8050 decreased apoptosis in the duct epithelium and the extent of epithelial injury after RRV challenge.
Conclusion:
The biliary epithelium undergoes early activation of apoptosis in a mouse model of biliary atresia. The synergistic role of IFNgamma and TNFalpha in activating caspase-3 in cholangiocytes and the decreased apoptosis following pharmacologic inhibition of caspases support a prominent role for apoptosis in the pathogenesis of experimental biliary atresia.
