Aims

Direct cardiac reprogramming represents an attractive way to reversing heart damage caused by myocardial infarction because it removes fibroblasts, while also generating new functional cardiomyocytes. Yet, the main hurdle for bringing this technique to the clinic is the lack of efficacy with current reprogramming protocols. Here, we describe our unexpected discovery that DMSO is capable of significantly augmenting direct cardiac reprogramming in vitro.

Methods and results

Upon induction with cardiac transcription factors- Gata4, Hand2, Mef2c and Tbx5 (GHMT), the treatment of mouse embryonic fibroblasts (MEFs) with 1% DMSO induced ~5 fold increase in Myh6-mCherry+ cells, and significantly upregulated global expression of cardiac genes, including Myh6, Ttn, Nppa, Myh7 and Ryr2. RNA-seq confirmed upregulation of cardiac gene programmes and downregulation of extracellular matrix-related genes. Treatment of TGF-β1, DMSO, or SB431542, and the combination thereof, revealed that DMSO most likely targets a separate but parallel pathway other than TGF-β signalling. Subsequent experiments using small molecule screening revealed that DMSO enhances direct cardiac reprogramming through inhibition of the CBP/p300 bromodomain, and not its acetyltransferase property.

Conclusion

In conclusion, our work points to a direct molecular target of DMSO, which can be used for augmenting GHMT-induced direct cardiac reprogramming and possibly other cell fate conversion processes.

中文翻译：

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二甲基亚砜 (DMSO) 通过抑制共激活剂 CBP/p300 的溴结构域来增强直接心脏重编程

目标

直接心脏重编程代表了逆转心肌梗塞引起的心脏损伤的一种有吸引力的方法，因为它去除了成纤维细胞，同时还产生了新的功能性心肌细胞。然而，将这种技术引入临床的主要障碍是目前的重编程方案缺乏疗效。在这里，我们描述了我们的意外发现，即 DMSO 能够显着增强体外直接心脏重编程。

方法和结果

用心脏转录因子Gata4、Hand2、Mef2c和Tbx5 (GHMT) 诱导后，用 1% DMSO 处理小鼠胚胎成纤维细胞 (MEF) 后，Myh6 -mCherry+ 细胞增加了约 5 倍，并显着上调了心脏基因的整体表达, 包括Myh6 , Ttn , Nppa , Myh7和Ryr2. RNA-seq 证实了心脏基因程序的上调和细胞外基质相关基因的下调。TGF-β1、DMSO 或 SB431542 及其组合的处理显示 DMSO 最有可能靶向除 TGF-β 信号传导之外的单独但平行的途径。随后使用小分子筛选的实验表明，DMSO 通过抑制 CBP/p300 溴结构域而不是其乙酰转移酶特性来增强直接心脏重编程。

结论

总之，我们的工作指向 DMSO 的直接分子靶点，可用于增强 GHMT 诱导的直接心脏重编程和可能的其他细胞命运转换过程。