Isolation and Characterization of Bipotent Liver Progenitor Cells from Adult Mouse

¹ Department of Cell Biology, Second Military Medical University, Xiangyin Rd. 800, Shanghai 200433, P. R. China
² Department of Pathology, Changzheng Hospital, Fengyang Rd. 415, Shanghai 200003, P. R. China
³ The Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263

^* To whom correspondence should be addressed. E-mail: yphu{at}smmu.edu.cn.

	Abstract

Liver progenitor cells have drawn a great deal of attention both for their therapeutic potential and for their usefulness in exploring the molecular events surrounding liver development and regeneration. Despite the intensive studies on liver progenitors from rat, equivalent progenitor cells derived from mice are relatively rare. We used retrosine treatment followed by partial hepatectomy to elicit liver progenitors in mice. From these animals showing prominent ductular reactions, mouse-derived liver progenitor cell lines (LEPCs) were isolated by single-cell cloning. Phenotypic and lineage profiling of the LEPCs clones were performed using immunochemistry, RT-PCR, and by using a "dual color" system comprising of the reporter EGFP under the control of the cytokeratin 19 promoter and the DsRed reporter under the control of the albumin promoter. LEPCs expressed liver progenitor cell markers. LEPCs also expressed some markers shared by bone marrow derived hematopoietic stem cells c-Kit, Thy-1, but not CD34 and CD45. When cultured as aggregates in Matrigel, LEPCs differentiated into hepatocyte upon treatment with 50ng/ml epithelial growth factor (EGF) or differentiated into biliary lineage cells upon treatment with 20ng/ml hepatocyte growth factor (HGF). In the presence of 2% DMSO and 2% Matrigel, LEPCs acquired predominantly bile lineage phenotypes with occasional patches of cells exhibiting hepatocyte phenotypes. Upon transplantation into CCl₄ -injured-liver, LEPCs engrafted into liver parenchyma and differentiated into hepatocytes. Considering the amenability of the mouse to genetic manipulation, these mouse-derived LEPCs may be useful tools as in vitro models to study molecular events in liver development and regeneration, and can shed light in studying the therapy potential of liver stem cells.