We previously demonstrated that hepatoblasts can be isolated from mouse fetal liver based on the expression of delta-like [corrected] (Dlk), also known as Pref-1. Each Dlk+ hepatoblast forms a colony containing both albumin+ hepatocytes and
cytokeratin 19+ (CK19) cholangiocytic cells on either
type IV collagen or
laminin. Here we show that extracellular matrices (ECMs) significantly affect the growth of Dlk+ cells. Dlk+ cells vigorously proliferated on
type IV collagen-coated dishes in the presence of
EGF and HGF during the first 5 days, but their proliferative capability declined thereafter. Dlk+ cells also proliferated on
laminin-coated plates and some colonies continued to expand even beyond one month after plating. These hepatic progenitor cells proliferating on
laminin (HPPL) efficiently proliferated even after replating. Moreover, they were induced to differentiate into hepatocytes and cholangiocytes by overlaying
Engelbreth-Holm-Swarm sarcoma (EHS) gel and by embedding in
type I collagen gel, respectively. HPPL acquired the metabolic functions of accumulating
polysaccharides and detoxifying
ammonium ions after hepatic differentiation. Surprisingly, HPPL expressed pancreatic genes such as Pdx1 when
dexamethasone was depleted from the culture medium. Therefore, the long-term culture of hepatoblasts on
laminin produces multi-potential hepatic progenitors, which possess a strong proliferative capability, differentiate into both hepatocytes and cholangiocytes, and potentially give rise to pancreatic cells.