Isolation and long-term maintenance of hepatic progenitor cells (HPCs) from healthy, non-injured adult livers remains challenging due to the lack of specific surface markers for selection and a limited understanding o...Isolation and long-term maintenance of hepatic progenitor cells (HPCs) from healthy, non-injured adult livers remains challenging due to the lack of specific surface markers for selection and a limited understanding of the mechanisms for maintaining self-renewal. Previously, we identified a Sca-1 positive, bipotent HPC population in the peri-portal region of adult liver, and found MAPK/ERK and Wnt/β-Catenin pathways to be synergistically involved in their proliferation. In this study, we report the long-term culture of Sca-1 positive HPCs with epidermal growth factor (EGF) and CHIR99021, a small molecule inhibitor of glycogen synthase kinase 3 (GSK-3). Sca-1+ HPCs remain non-tumorigenic when passaged 35 times in vitro over 1 year. Flow cytometric analysis indicates that HPCs are positive for Sca-1 and putative liver progenitor cell markers, including CD13, CD24 and Prominin-1, but negative for hematopoietic/endothelial cell markers CD31, CD34, CD45, CD90 and CD117. Immunocyto-chemistry and RT-PCR indicate Sca-1+ HPCs express albumin (ALB), α-fetoprotein (AFP), cytokeratin19 (CK19), Sox9 and a panel of special hepatic progenitor transcriptional factors. Moreover, Sca-1+ HPCs are able to differentiate into hepatocyte-like and cholangiocyte-like cells under appropriate culture conditions in vitro and can take part in liver repopulation in an acetaminophen (APAP) induced liver injury mouse model. This study provides a paradigm to capture and maintain HPCs from naive liver tissue and offers a valuable cell model for investigating the molecular mechanisms underlying the cell lineage relationship in normal liver.展开更多
文摘Isolation and long-term maintenance of hepatic progenitor cells (HPCs) from healthy, non-injured adult livers remains challenging due to the lack of specific surface markers for selection and a limited understanding of the mechanisms for maintaining self-renewal. Previously, we identified a Sca-1 positive, bipotent HPC population in the peri-portal region of adult liver, and found MAPK/ERK and Wnt/β-Catenin pathways to be synergistically involved in their proliferation. In this study, we report the long-term culture of Sca-1 positive HPCs with epidermal growth factor (EGF) and CHIR99021, a small molecule inhibitor of glycogen synthase kinase 3 (GSK-3). Sca-1+ HPCs remain non-tumorigenic when passaged 35 times in vitro over 1 year. Flow cytometric analysis indicates that HPCs are positive for Sca-1 and putative liver progenitor cell markers, including CD13, CD24 and Prominin-1, but negative for hematopoietic/endothelial cell markers CD31, CD34, CD45, CD90 and CD117. Immunocyto-chemistry and RT-PCR indicate Sca-1+ HPCs express albumin (ALB), α-fetoprotein (AFP), cytokeratin19 (CK19), Sox9 and a panel of special hepatic progenitor transcriptional factors. Moreover, Sca-1+ HPCs are able to differentiate into hepatocyte-like and cholangiocyte-like cells under appropriate culture conditions in vitro and can take part in liver repopulation in an acetaminophen (APAP) induced liver injury mouse model. This study provides a paradigm to capture and maintain HPCs from naive liver tissue and offers a valuable cell model for investigating the molecular mechanisms underlying the cell lineage relationship in normal liver.
