Developmental Molecular Mechanisms | Protein Chemistry & Proteomics | Morphogenesis & Cell Biology | Cell Growth & Division | Control of Gene Expression | Stem Cells & Regeneration
A novel marker of undifferentiated liver progenitor cells
R. Y. W Huang, C. C. Chiu, L. L. Chiou, G. T. Huang, H. S. Lee*
*Corresponding author: H. S. Lee
Institute of Biotechnology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan
Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
F1000Posters 2010, 1: 81 (poster) [ENGLISH]
American Society of Cell Biology Annual Meeting 2009, 5 - 9 Dec 2009, 782/B729
Although some of hepatic progenitor cells have been characterized, up to now, neither liver stem cells nor universal liver stem cell markers have been identified. An adult rat liver stem cell line, Lig-8, has been derived from non-parenchymal fraction of F344 rats. This study is to identify and characterize the rat stem cell marker, LigAg, which is specifically expressed in Lig-8 cells and recognized by our derived monoclonal antibody, named Ligab.
To generate monoclonal antibody Ligab, we subcutaneously injected whole Lig-8 cells into mice. The Ligab specifically recognizes its target antigen (LigAg) with native form expressed by Lig-8 cells. To detect the presence of LigAg in Lig-8 cells and the localization of LigAg-bearing cells in rat liver, we indirectly conjugated Ligab with FITC to perform immunofluorescent stain. For in vitro differentiation, sodium butyrate (SB) was used to induce Lig-8 cell differentiation, and differentiated properties of expression of cytokeratin (CK)-19 and albumin were detected by PCR and immunocytostaining. To identify LigAg, we extracted different fractions of proteins from Lig-8 cells followed by immunoprecipitation and analyzed with SDS-PAGE. The identified bands in SDS-PAGE will be excised for peptide sequencing.
The Ligab yielded belongs to IgG subclass G1. Lig-Ag is expressed on membrane and in cytoplasm of Lig-8 cells. Ligab could detect its antigen only by native PAGE-based immnoblotting. Indirect immunohistochemical staining in rat normal liver sections distinguishes LigAg bearing cells from currently known hepatic progenitor cells. In the induction with SB in vitro, Lig-8 cells were shown able to differentiate into both hepatocytes and bile duct cells with prospective markers expression. More interestingly, LigAg was decreasingly expressed along with Lig-8 cells differentiation.
Conclusions: Inasmuch as our results showed LigAg was specifically expressed in rat hepatic progenitor cells, and its expression in a decreasing trend with Lig-8 cells differentiation. LigAg can be a differentiation-related marker for these cells and Ligab may help study the molecular mechanisms of liver progenitor cell differentiation.
No relevant conflicts of interest declared.
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