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Bi Y.,Chongqing Medical University | Bi Y.,Chongqing Stem Cell Therapy Engineering and Technology Center | He Y.,Chongqing Medical University | He Y.,Chongqing Stem Cell Therapy Engineering and Technology Center | And 47 more authors.
Cellular Physiology and Biochemistry | Year: 2014

Background/Aims: Liver is a vital organ and retains its regeneration capability throughout adulthood, which requires contributions from different cell populations, including liver precursors and intrahepatic stem cells. To overcome the mortality of hepatic progenitors (iHPs) in vitro, we aim to establish reversibly immortalized hepatic progenitor cells from mouse embryonic liver. Methods and Results: Using retroviral system to stably express SV40 T antigen fanked with Cre/LoxP sites, we establish a repertoire of iHP clones with varied differentiation potential. The iHP cells maintain long-term proliferative activity and express varied levels of progenitor markers (Pou5f1/Oct4 and Dlk) and hepatocyte markers (AFP, Alb and ApoB). Five representative iHP clones express hepatic/pancreatic transcription factors HNF3α/Foxa1, HNF3β/Foxa2, and HNF4α/MODY1. Dexamethasone is shown to promote the expression of hepatocyte markers AFP and TAT, along with ICG-uptake and glycogen storage functions in the iHP clones. Cre-mediated removal of SV40 T antigen reverses the proliferative activity of iHP cells. When iHP cells are subcutaneously implanted in athymic nude mice, no tumor formation is observed for up to 8 weeks. Conclusions: We demonstrate that the established iHP cells are stable, reversible, and non-tumorigenic hepatic progenitor-like cells, which should be valuable for studying liver organogenesis, metabolic regulations, and hepatic lineage-specifc differentiation. Copyright © 2014 S. Karger AG, Basel.

Yang K.,Chongqing Medical University | Yang K.,University of Chicago | Yang K.,Chongqing Stem Cell Therapy Engineering and Technology Center | Wang X.,University of Chicago | And 18 more authors.
Laboratory Investigation | Year: 2016

The canonical WNT/β-catenin signaling pathway governs a myriad of biological processes underlying the development and maintenance of adult tissue homeostasis, including regulation of stem cell self-renewal, cell proliferation, differentiation, and apoptosis. WNTs are secreted lipid-modified glycoproteins that act as short-range ligands to activate receptor-mediated signaling pathways. The hallmark of the canonical pathway is the activation of β-catenin-mediated transcriptional activity. Canonical WNTs control the β-catenin dynamics as the cytoplasmic level of β-catenin is tightly regulated via phosphorylation by the 'destruction complex', consisting of glycogen synthase kinase 3β (GSK3β), casein kinase 1α (CK1α), the scaffold protein AXIN, and the tumor suppressor adenomatous polyposis coli (APC). Aberrant regulation of this signaling cascade is associated with varieties of human diseases, especially cancers. Over the past decade, significant progress has been made in understanding the mechanisms of canonical WNT signaling. In this review, we focus on the current understanding of WNT signaling at the extracellular, cytoplasmic membrane, and intracellular/nuclear levels, including the emerging knowledge of cross-talk with other pathways. Recent progresses in developing novel WNT pathway-targeted therapies will also be reviewed. Thus, this review is intended to serve as a refresher of the current understanding about the physiologic and pathogenic roles of WNT/β-catenin signaling pathway, and to outline potential therapeutic opportunities by targeting the canonical WNT pathway. © 2016 USCAP, Inc All rights reserved.

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