Yang Jinpu, Kaur Keerat, Edwards John G, Eisenberg Carol A, Eisenberg Leonard M
New York Medical College/Westchester Medical Center Stem Cell Laboratory, Departments of Physiology and Medicine, New York Medical College, Valhalla, NY 10595, USA.
Department of Biology and Genomics, New York University, New York, NY 10003, USA.
Stem Cells Int. 2017;2017:3464953. doi: 10.1155/2017/3464953. Epub 2017 Jul 16.
Previously, we reported that treatment with the G9a histone methyltransferase inhibitor BIX01294 causes bone marrow mesenchymal stem cells (MSCs) to exhibit a cardiocompetent phenotype, as indicated by the induction of the precardiac markers Mesp1 and brachyury. Here, we report that combining the histone deacetylase inhibitor trichostatin A (TSA) with BIX01294 synergistically enhances MSC cardiogenesis. Although TSA by itself had no effect on cardiac gene expression, coaddition of TSA to MSC cultures enhanced BIX01294-induced levels of Mesp1 and brachyury expression 5.6- and 7.2-fold. Moreover, MSCs exposed to the cardiogenic stimulus Wnt11 generated 2.6- to 5.6-fold higher levels of the cardiomyocyte markers GATA4, Nkx2.5, and myocardin when pretreated with TSA in addition to BIX01294. MSC cultures also showed a corresponding increase in the prevalence of sarcomeric protein-positive cells when treated with these small molecule inhibitors. These results correlated with data showing synergism between (1) TSA and BIX01294 in promoting acetylation of lysine 27 on histone H3 and (2) BIX01294 and Wnt11 in decreasing -catenin accumulation in MSCs. The implications of these findings are discussed in light of observations in the early embryo on the importance of -catenin signaling and histone modifications for cardiomyocyte differentiation and heart development.
此前，我们报道过，使用G9a组蛋白甲基转移酶抑制剂BIX01294进行处理会使骨髓间充质干细胞（MSC）呈现心脏祖细胞表型，这可通过心脏前体细胞标志物Mesp1和短尾相关蛋白的诱导表达来表明。在此，我们报道，将组蛋白去乙酰化酶抑制剂曲古抑菌素A（TSA）与BIX01294联合使用可协同增强MSC向心肌细胞的分化。尽管TSA单独使用时对心脏基因表达没有影响，但在MSC培养物中同时添加TSA可使BIX01294诱导的Mesp1和短尾相关蛋白表达水平分别提高5.6倍和7.2倍。此外，当除了BIX01294之外还用TSA进行预处理时，暴露于心脏发生刺激因子Wnt11的MSC产生的心肌细胞标志物GATA4、Nkx2.5和心肌转录因子的水平要高出2.6至5.6倍。在用这些小分子抑制剂处理时，MSC培养物中肌节蛋白阳性细胞的比例也相应增加。这些结果与以下数据相关：（1）TSA和BIX01294在促进组蛋白H3赖氨酸27乙酰化方面具有协同作用；（2）BIX01294和Wnt11在降低MSC中β-连环蛋白积累方面具有协同作用。结合早期胚胎中关于β-连环蛋白信号传导和组蛋白修饰对心肌细胞分化和心脏发育的重要性的观察结果，对这些发现的意义进行了讨论。
