肝细胞极化标志分子在骨髓基质干细胞向肝细胞分化过程中的表达

Expression of cell polarization molecules during the differentiation of bone marrow stem cell-derived hepatocytes

目的观察在体外诱导成人骨髓基质干细胞向肝细胞分化过程中肝细胞极化标志分子的表达和分布。方法从成人骨髓中分离基质干细胞,在体外诱导分化为成熟肝细胞。应用半定量逆转录-聚合酶链反应(RT-PCR)方法比较肝细胞极化标志蛋白二肽酰基肽酶Ⅳ(DPPⅣ)和低密度脂蛋白受体(LDLr)mRNA在诱导分化(实验组)和非诱导分化(对照组)条件下的表达情况。应用免疫荧光方法在共聚焦显微镜下观察DPPⅣ和LDLr在细胞膜上的分布情况。结果成人骨髓来源的基质干细胞经诱导后分化表达白蛋白,实验组DPPⅣ和LDLr mRNA的表达高于对照组(P＜0．05)。DPPⅣ和LDLr在肝细胞膜上呈特征性分布。结论成人骨髓基质干细胞在向肝细胞分化过程中表达肝细胞极化标志分子,进一步表明骨髓基质干细胞具有向肝细胞分化的潜能。同时,肝细胞体外分化可以做为研究肝细胞极化形成机制的良好模型。

Objective To Study the expression and distribution pattern of cell polarization molecules during the differentiation of human bone marrow stem cells in hepatocytes in vitro. Methods Adult bone marrow cells were isolated and induced into mature hepatocytes in vitro. The mRNA expression of polarized hepatocyte marker molecules, dipeptidylpeptidase Ⅳ （DPPIV） and low density lipoprorein receptor （LDLr）, was compared between induced and non-induced cultures using semi-quantitative RT-PCR. The distribution patterns of DPPIV and LDLr were observed immunohistochemically by confo- cal microscopy. Results Albumin was expressed in cells after the induction by adult human bone marrow. The mRNA expression level of DPPIV and LDLr was higher in induced cultures than that in non- induced counterparts （P 〈 0.05）. The protein expression of DPPIV and LDLr on the cell membrane was characteristic. Conclusion Cell polarization molecules were expressed during the differentiation of human bone marrow stem cells into hepatocytes. The evidence not only demonstrates the potential of bone marrow stem cells to differentiate towards hepatocyte phenotype,but also provides a model for studying the mechanism of hepatocyte polarization.