期刊
HEPATOLOGY
卷 60, 期 3, 页码 964-976出版社
WILEY-BLACKWELL
DOI: 10.1002/hep.27082
关键词
-
资金
- NIH [1R01DK62277, 1R01DK100287]
- Endowed Chair for Experimental Pathology
- [5R01AR053293]
- [5R21RR024887]
- Grants-in-Aid for Scientific Research [23791549] Funding Source: KAKEN
Liver-specific beta-catenin knockout (beta-catenin-LKO) mice have revealed an essential role of beta-catenin in metabolic zonation where it regulates pericentral gene expression and in initiating liver regeneration (LR) after partial hepatectomy (PH), by regulating expression of Cyclin-D1. However, what regulates beta-catenin activity in these events remains an enigma. Here we investigate to what extent beta-catenin activation is Wnt-signalingdependent and the potential cell source of Wnts. We studied liver-specific Lrp5/6 KO (Lrp-LKO) mice where Wnt-signaling was abolished in hepatocytes while the beta-catenin gene remained intact. Intriguingly, like beta-catenin-LKO mice, Lrp-LKO exhibited a defect in metabolic zonation observed as a lack of glutamine synthetase (GS), Cyp1a2, and Cyp2e1. Lrp-LKO also displayed a significant delay in initiation of LR due to the absence of beta-catenin-TCF4 association and lack of Cyclin-D1. To address the source of Wnt proteins in liver, we investigated conditional Wntless (Wls) KO mice, which lacked the ability to secrete Wnts from either liver epithelial cells (Wls-LKO), or macrophages including Kupffer cells (Wls-MKO), or endothelial cells (Wls-EKO). While Wls-EKO was embryonic lethal precluding further analysis in adult hepatic homeostasis and growth, Wls-LKO and Wls-MKO were viable but did not show any defect in hepatic zonation. Wls-LKO showed normal initiation of LR; however, Wls-MKO showed a significant but temporal deficit in LR that was associated with decreased beta-catenin-TCF4 association and diminished Cyclin-D1 expression. Conclusion: Wnt-signaling is the major upstream effector of beta-catenin activity in pericentral hepatocytes and during LR. Hepatocytes, cholangiocytes, or macrophages are not the source of Wnts in regulating hepatic zonation. However, Kupffer cells are a major contributing source of Wnt secretion necessary for beta-catenin activation during LR.
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