title: Self-renewal of hepatoblasts under chemically defined conditions by iterative growth factor and chemical screening.
abstract: Tissue-specific stem/progenitor cells are essential to mediate organogenesis and tissue homeostasis. In addition, these cells have attracted significant interest for their therapeutic potential. However, it remains challenging to expand most types of these cells in vitro. In this study we devised a screening strategy aimed at identifying growth factors and small molecules that can sustain self-renewal of mouse hepatoblasts. This approach began with a defined basal condition, on top of which collections of growth factors and bioactive small molecules were screened for maintaining self-renewal of primary hepatoblasts. The initially identified proteins and small molecules were then combined in the basal media for subsequent screening to identify additional molecules that can synergistically promote hepatoblast self-renewal. This strategy was performed iteratively to eventually define a small molecule and growth factor cocktail, including epidermal growth factor, glycogen synthase kinase 3 inhibitor, transforming growth factor β receptor inhibitor, lysophosphatidic acid, and sphingosine 1-phosphate, which was sufficient to sustain long-term self-renewal of the murine hepatoblasts under chemically defined conditions. These expanded hepatoblasts retain the ability to respond to liver developmental cues and produce functional hepatocytes and form bile duct-like structures.
  
  
  CONCLUSIONS
  Our work established a chemically defined condition that allows long-term expansion of hepatoblasts, improved our understanding of hepatoblast self-renewal, and highlights the power of phenotypic screening to enable self-renewal of somatic stem/progenitor cells.
authors.affiliation: Department of Cell Biology, Second Military Medical University, Shanghai, China.
authors.forename: Linjie
authors.initials: L
authors.lastname: Lv
authors.forename: Qingwang
authors.initials: Q
authors.lastname: Han
authors.forename: Yinghao
authors.initials: Y
authors.lastname: Chu
authors.forename: Muzi
authors.initials: M
authors.lastname: Zhang
authors.forename: Lin
authors.initials: L
authors.lastname: Sun
authors.forename: Wanguo
authors.initials: W
authors.lastname: Wei
authors.forename: Caixia
authors.initials: C
authors.lastname: Jin
authors.forename: Wenlin
authors.initials: W
authors.lastname: Li
mesh_terms: D000818:Animals; D001549:Benzamides; D018929:Cell Culture Techniques; D003470:Culture Media; D004149:Dioxoles; D004815:Epidermal Growth Factor; D005260:Female; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors; D022781:Hepatocytes / Q000166:cytology*; D008099:Liver / Q000166:cytology*; D008815:Mice, Inbred Strains; D011247:Pregnancy; D011720:Pyrazoles; D011725:Pyridines; D011743:Pyrimidines; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects
chemical_list: C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D001549:Benzamides; C473711:Chir 99021; D003470:Culture Media; D004149:Dioxoles; D011720:Pyrazoles; D011725:Pyridines; D011743:Pyrimidines; D018125:Receptors, Transforming Growth Factor beta; C550621:RepSox; D004815:Epidermal Growth Factor; D038362:Glycogen Synthase Kinase 3