Tissue Engineering Laboratory & Berlin-Brandenburg Center for Regenerative Therapies, Dept. of Rheumatology and Clinical Immunology, Charité-University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany.
Differentiation. 2013 Feb;85(3):78-90. doi: 10.1016/j.diff.2013.02.001. Epub 2013 May 3.
It is generally accepted that after differentiation bone marrow mesenchymal stem cells (MSC) become lineage restricted and unipotent in an irreversible manner. However, current results imply that even terminally differentiated cells transdifferentiate across lineage boundaries and therefore act as a progenitor cells for other lineages. This leads to the questions that whether transdifferentiation occurs via direct cell-to-cell conversion or dedifferentiation to a progenitor cells and subsequent differentiation, and whether MSC potency decreases or increases during differentiation. To address these questions, MSC were differentiated into adipogenic lineage cells, followed by dedifferentiation. The process of dedifferentiation was also confirmed by single cell clonal analysis. Finally the dedifferentiated cells were used for adipogenesis, osteogenesis and chondrogenesis. Histology, FACS, qPCR and GeneChip analyses of undifferentiated MSC, adipogenic-differentiated and dedifferentiated cells were performed. Interestingly, gene profiling and bioinformatics demonstrated that upregulation (DHCR24, G0S2, MAP2K6, SESN3) and downregulation (DST, KAT2, MLL5, RB1, SMAD3, ZAK) of distinct genes have an association with cell cycle arrest in adipogenic-differentiated cells and perhaps narrow down the lineage potency. However, the upregulation (CCND1, CHEK, HGF, HMGA2, SMAD3) and downregulation (CCPG1, RASSF4, RGS2) of these genes have an association with cell cycle progression and maybe motivate dedifferentiation of adipogenic-differentiated cells. We found that dedifferentiated cells have a multilineage potency comparable to MSC, and also observed the associative role of proliferation genes with cell cycle arrest and progression. Concluded, our results indicate that transdifferentiation of adipogenic-differentiated cells into osteogenic- or chondrogenic-differentiated cells proceeds via dedifferentiation and correlates with cell cycle arresting and deriving genes. Regarding clinical use, the knowledge of potency and underlying mechanisms are prerequisites.
人们普遍认为，骨髓间充质干细胞（MSC）在分化后会不可逆地成为谱系受限的单能细胞。然而，目前的结果表明，即使是终末分化的细胞也会跨谱系界限转分化，因此它们充当其他谱系的祖细胞。这就引出了一些问题，即转分化是通过直接的细胞-细胞转化还是去分化为祖细胞并随后分化发生的，以及 MSC 在分化过程中是否会减少或增加其多能性。为了解决这些问题，我们将 MSC 分化为成脂谱系细胞，然后进行去分化。单细胞克隆分析也证实了去分化的过程。最后，将去分化的细胞用于成脂、成骨和成软骨分化。对未分化的 MSC、成脂分化和去分化的细胞进行了组织学、FACS、qPCR 和 GeneChip 分析。有趣的是，基因谱分析和生物信息学表明，在成脂分化细胞中，某些基因的上调（DHCR24、G0S2、MAP2K6、 SESN3）和下调（DST、KAT2、MLL5、RB1、SMAD3、ZAK）与细胞周期停滞有关，也许可以缩小谱系多能性的范围。然而，这些基因的上调（CCND1、CHEK、HGF、HMGA2、SMAD3）和下调（CCPG1、RASSF4、RGS2）与细胞周期进程有关，可能会促使成脂分化的细胞去分化。我们发现，去分化的细胞具有与 MSC 相当的多谱系潜能，并且还观察到增殖基因与细胞周期停滞和进展的关联作用。总之，我们的结果表明，成脂分化的细胞向成骨或成软骨分化的转分化是通过去分化发生的，并且与细胞周期停滞和相关基因有关。就临床应用而言，对多能性和潜在机制的了解是前提条件。
