State Key Laboratory of Cancer Biology, Xijing Hospital of Digestive Diseases, The Fourth Military Medical University, Xi'an, Shaanxi Province, China.
PLoS One. 2012;7(9):e44737. doi: 10.1371/journal.pone.0044737. Epub 2012 Sep 12.
Despite the extensive hepatic differentiation potential of human umbilical cord lining-derived mesenchymal stem cells (hUC-MSC), little is known about the molecular mechanisms of hUC-MSC differentiation. At the post-transcriptional level, microRNAs are key players in the control of cell fate determination during differentiation. In this study, we aimed to identify microRNAs involved in the hepatic differentiation of hUC-MSCs. After successfully isolating hUC- MSCs, we induced hepatocyte formation in vitro with growth factors. After 26 days of induction, hUC-MSCs could express hepatocyte-specific genes, synthesize urea and glycogen and uptake low-density lipoprotein. Cellular total RNA from hUC-MSCs and hepatic differentiated hUC-MSCs was collected at 7 time points, including 2 days, 6 days, 10 days, 14 days, 22 days and 26 days, for microRNA microarray analysis. Dynamic microRNA profiles were identified that did not overlap or only partially overlapped with microRNAs reported to be involved in human liver development, hepatocyte regeneration or hepatic differentiation of liver-derived progenitor cells. A total of 61 microRNAs among 1205 human and 144 human viral microRNAs displayed consistent changes and were altered at least 2-fold between hUC-MSCs and hepatic differentiated hUC-MSCs. Among these microRNAs, 25 were over-expressed; this over-expression occurred either gradually or increased sharply and was maintained at a high level. A total of 36 microRNAs were under-expressed, with an expression pattern similar to that of the over-expressed microRNAs. The expression of the altered expressed microRNAs was also confirmed by quantitative reverse-transcription polymerase chain reaction. We also found that microRNAs involved in hepatic differentiation were not enriched in hepatocyte or hepatocellular carcinoma cells and can potentially target liver-enriched transcription factors and genes. The elucidation of the microRNA profile during the hepatic differentiation of hUC-MSCs provides the basis for clarifying the role of microRNAs in hUC-MSC hepatic differentiation and specific microRNA selection for the conversion of hUC-MSCs to hepatocytes.
尽管人脐带衬里来源间充质干细胞 (hUC-MSC) 具有广泛的肝分化潜能，但对于 hUC-MSC 分化的分子机制知之甚少。在转录后水平，microRNAs 是控制分化过程中细胞命运决定的关键因素。在这项研究中，我们旨在鉴定参与 hUC-MSC 肝分化的 microRNAs。成功分离 hUC-MSC 后，我们用生长因子在体外诱导肝细胞形成。诱导 26 天后，hUC-MSC 可以表达肝细胞特异性基因、合成尿素和糖原并摄取低密度脂蛋白。在 7 个时间点收集 hUC-MSC 和肝分化 hUC-MSC 的细胞总 RNA，包括 2 天、6 天、10 天、14 天、22 天和 26 天，进行 microRNA 微阵列分析。确定了动态 microRNA 谱，这些谱与参与人类肝脏发育、肝细胞再生或肝源性祖细胞肝分化的 microRNAs 不重叠或仅部分重叠。在 1205 个人类和 144 个人类病毒 microRNAs 中，共有 61 个 microRNAs 显示出一致的变化，在 hUC-MSC 和肝分化 hUC-MSC 之间至少有 2 倍的变化。在这些 microRNAs 中，25 个被过度表达；这种过表达要么逐渐发生，要么急剧增加，并保持在高水平。共有 36 个 microRNAs 被低表达，表达模式与过表达的 microRNAs 相似。通过定量逆转录聚合酶链反应也证实了改变表达的 microRNAs 的表达。我们还发现，参与肝分化的 microRNAs 不在肝细胞或肝癌细胞中富集，并且可以潜在地靶向肝脏丰富的转录因子和基因。阐明 hUC-MSC 肝分化过程中的 microRNA 谱为阐明 microRNAs 在 hUC-MSC 肝分化中的作用以及特定 microRNA 选择用于 hUC-MSC 向肝细胞的转化提供了基础。
