Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, China.
Dev Growth Differ. 2012 Jun;54(5):605-17. doi: 10.1111/j.1440-169X.2012.01363.x. Epub 2012 Jun 10.
Cell transplantation is efficient method to therapy end-stage liver disease (ESLD). How to punctually induce stem cell differentiation into hepatocyte is still a challenge. Notch plays important roles in embryonic development and cell differentiation. However, during the differentiation process from fetal liver stem/progenitor cells (FLSPCs) to mature hepatocytes, the contribution of Notch, especially which Notch receptor is primarily responsible, is unknown. First, specific Notch receptor responsible for FLSPCs differentiation was identified. On both tissue level and cell level, we found that Notch3 was the only receptor greater expressed in liver tissue at embryonic day (ED) 14 and FLSPCs, compared with the adult liver and BRL cells, respectively. Second, morphological phenotypic and functional aspects were analyzed to evaluate whether Notch inhibition by GSIs (γ-secretase inhibitors, inhibitor of Notch) promotes the differentiation of FLSPCs into hepatocytes. Results showed that N-[N-(3, 5-Difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) as GSIs was able to induce FLSPCs differentiation into hepatocytes. The differentiated FLSPCs showed similar morphology to mature hepatocytes, expressed hepatic markers indicative of a mature developmental stage, and displayed similar functionality to mature hepatocytes. The differentiation efficiency by GSIs was similar to that by hepatocyte growth factor (HGF) induction. More specifically, as the differentiation of FLSPCs progressed towards hepatocytes, the expression of Notch3 was gradually down-regulated, consistent with the down-regulation of other stem cell markers. These findings imply that Notch3 may not only be a regulator of FLSPCs differentiation into hepatocytes, but also be a potential marker of FLSPCs.
细胞移植是治疗终末期肝病（ESLD）的有效方法。如何及时诱导干细胞分化为肝细胞仍然是一个挑战。Notch 在胚胎发育和细胞分化中发挥重要作用。然而，在从胎肝干细胞/祖细胞（FLSPCs）分化为成熟肝细胞的过程中，Notch 的作用，特别是哪个 Notch 受体起主要作用，尚不清楚。首先，确定了负责 FLSPCs 分化的特定 Notch 受体。在组织和细胞水平上，我们发现 Notch3 是胚胎第 14 天（ED）肝脏组织和 FLSPCs 中表达高于成年肝脏和 BRL 细胞的唯一受体。其次，分析了形态表型和功能方面，以评估 Notch 抑制剂（γ-分泌酶抑制剂，Notch 抑制剂）是否促进 FLSPCs 向肝细胞分化。结果表明，作为 GSIs 的 N-[N-（3,5-二氟苯乙酰基）-L-丙氨酰]-S-苯甘氨酸叔丁酯（DAPT）能够诱导 FLSPCs 分化为肝细胞。分化的 FLSPCs 表现出与成熟肝细胞相似的形态，表达指示成熟发育阶段的肝标志物，并表现出与成熟肝细胞相似的功能。GSIs 的分化效率与肝细胞生长因子（HGF）诱导的分化效率相似。更具体地说，随着 FLSPCs 向肝细胞分化的进展，Notch3 的表达逐渐下调，与其他干细胞标志物的下调一致。这些发现表明 Notch3 不仅可能是 FLSPCs 向肝细胞分化的调节剂，而且可能是 FLSPCs 的潜在标志物。
