Direct conversion by overexpression of defined transcription factors (TFs) is a promising new method that can generate desired cell types from abundant, accessible cells. While previous studies have reported hepatic generation from fibroblasts, tremendous interest exists in the understanding of hepatic reprograming and its applicability in regenerative medicine. Here, we show that overexpression of Yamanaka factors can induce reprograming of mouse fibroblasts into cells that closely resemble hepatocytes in vitro in the presence of an optimized hepatic growth medium. By screening the effects of 20 candidate transcription factors, we identified a combination of three TFs (Hnf4a, Cebpa, and Nr1i2) that can convert fibroblasts into a hepatic fate. These factors in conjunction with Yamanaka factors increase the efficiency of hepatic reprograming. The induced hepatocyte-like (iHep) cells have multiple hepatocyte-specific characteristics; express hepatocyte-specific markers, glycogen storage, albumin secretion, urea production, as well as low-density lipoprotein and indocyanin green uptake. Production of iHep cells by these novel approaches may bring new insights into the molecular nature of hepatocyte differentiation and future cell-based therapeutics for liver diseases.

中文翻译：

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转录因子介导的成纤维细胞重编程为肝细胞样细胞。

通过过量表达已定义的转录因子（TF）进行直接转化是一种有前途的新方法，可以从大量可及的细胞中产生所需的细胞类型。尽管先前的研究报道了从成纤维细胞生成肝，但是人们对肝重编程及其在再生医学中的适用性有着极大的兴趣。在这里，我们显示Yamanaka因子的过表达可以诱导小鼠成纤维细胞重编程为在体外存在优化的肝生长培养基的情况下非常类似于肝细胞的细胞。通过筛选20种候选转录因子的作用，我们鉴定了可以将成纤维细胞转化为肝命运的三种TF（Hnf4a，Cebpa和Nr1i2）的组合。这些因素与Yamanaka因素一起提高了肝脏重编程的效率。诱导的肝细胞样（iHep）细胞具有多种肝细胞特有的特征；表达肝细胞特异性标志物，糖原储存，白蛋白分泌，尿素生成以及低密度脂蛋白和吲哚青绿的吸收。通过这些新颖的方法生产iHep细胞，可能会为肝细胞分化的分子性质和未来用于肝病的基于细胞的疗法带来新的见解。