Laboratório de Biologia Básica de Células-Tronco, Instituto Carlos Chagas, FIOCRUZ, Curitiba, PR, Brasil.
Braz J Med Biol Res. 2013 May;46(5):405-16. doi: 10.1590/1414-431X20132893.
Epigenetic mechanisms such as DNA methylation and histone modification are important in stem cell differentiation. Methylation is principally associated with transcriptional repression, and histone acetylation is correlated with an active chromatin state. We determined the effects of these epigenetic mechanisms on adipocyte differentiation in mesenchymal stem cells (MSCs) derived from bone marrow (BM-MSCs) and adipose tissue (ADSCs) using the chromatin-modifying agents trichostatin A (TSA), a histone deacetylase inhibitor, and 5-aza-2'-deoxycytidine (5azadC), a demethylating agent. Subconfluent MSC cultures were treated with 5, 50, or 500 nM TSA or with 1, 10, or 100 µM 5azadC for 2 days before the initiation of adipogenesis. The differentiation was quantified and expression of the adipocyte genes PPARG and FABP4 and of the anti-adipocyte gene GATA2 was evaluated. TSA decreased adipogenesis, except in BM-MSCs treated with 5 nM TSA. Only treatment with 500 nM TSA decreased cell proliferation. 5azadC treatment decreased proliferation and adipocyte differentiation in all conditions evaluated, resulting in the downregulation of PPARG and FABP4 and the upregulation of GATA2. The response to treatment was stronger in ADSCs than in BM-MSCs, suggesting that epigenetic memories may differ between cells of different origins. As epigenetic signatures affect differentiation, it should be possible to direct the use of MSCs in cell therapies to improve process efficiency by considering the various sources available.
表观遗传机制，如 DNA 甲基化和组蛋白修饰，在干细胞分化中起着重要作用。甲基化主要与转录抑制有关，而组蛋白乙酰化与活性染色质状态相关。我们使用组蛋白去乙酰化酶抑制剂曲古抑菌素 A（TSA）和去甲基化剂 5-氮杂-2′-脱氧胞苷（5azadC），研究了这些表观遗传机制对骨髓间充质干细胞（BM-MSCs）和脂肪组织来源的间充质干细胞（ADSCs）中成脂分化的影响。在诱导成脂分化前，将亚汇合的 MSC 培养物用 5、50 或 500nM TSA 或 1、10 或 100μM 5azadC 处理 2 天。定量分化，并评估脂肪细胞基因 PPARG 和 FABP4 以及抗脂肪细胞基因 GATA2 的表达。TSA 降低了成脂分化，除了用 5nM TSA 处理的 BM-MSCs 之外。只有用 500nM TSA 处理才会降低细胞增殖。5azadC 处理降低了所有评估条件下的增殖和成脂分化，导致 PPARG 和 FABP4 下调，GATA2 上调。与 BM-MSCs 相比，ADSCs 对处理的反应更强，这表明不同来源的细胞之间可能存在不同的表观遗传记忆。由于表观遗传特征会影响分化，因此通过考虑可用的各种来源，有可能指导间充质干细胞在细胞治疗中的使用，以提高过程效率。
