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A Mouse Model of Chronic Liver Fibrosis for the Study of Biliary Atresia
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YAP, but Not RSPO-LGR4/5, Signaling in Biliary Epithelial Cells Promotes a Ductular Reaction in Response to Liver
Lara Planas-Paz1, Tianliang Sun1, Monika Pikiolek1
1Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland.
Cell Stem Cell
|May 14, 2019
Summary
Biliary epithelial cells (BECs) are not reliant on WNT/β-catenin signaling for liver regeneration. YAP and mTORC1 pathways are crucial for ductular reaction (DR), while AXIN2 and LGR5 upregulation aids hepatocyte regeneration.
Area of Science:
- Hepatology and Stem Cell Biology
- Liver Regeneration and Injury Response
Background:
- Biliary epithelial cells (BECs) are facultative liver stem cells crucial for ductular reaction (DR) during liver regeneration.
- Periportal LGR5+ cells are implicated as stem cells in liver injury, with WNT/β-catenin signaling suggested to be vital for DR.
Purpose of the Study:
- To investigate the roles of WNT/β-catenin and other signaling pathways in BECs during liver ductular reaction (DR).
- To clarify the identity and function of injury-induced periportal LGR5+ cells in liver regeneration.
Main Methods:
- Conducted a CRISPR-based loss-of-function screen in BEC-like organoids.
- Performed in vivo validation and single-cell RNA sequencing.
- Analyzed signaling pathway involvement in ductular reaction.
Main Results:
- BECs do not require LGR4/5-mediated WNT/β-catenin signaling for DR.
- YAP and mTORC1 signaling pathways are essential for ductular reaction.
- Upregulation of AXIN2 and LGR5 in hepatocytes is necessary for their regenerative capacity post-injury.
Conclusions:
- Highlights heterogeneity within the biliary epithelial cell pool.
- Delineates key signaling pathways (YAP, mTORC1) driving ductular reaction.
- Clarifies the role of AXIN2 and LGR5 in hepatocyte regeneration.
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