Department of Cell Biology, Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, China.
J Cell Physiol. 2014 Jun;229(6):801-12. doi: 10.1002/jcp.24501.
The potential of adult human adipose tissue stem cells (hASCs) to differentiate into hepatocytes has generated much excitement over the possible use of hASCs in therapeutic applications. An understanding of the molecular mechanisms that underlie the plasticity of hASCs toward hepatocytes will help to make this possibility a reality. Herein, we show that a homogenous population of hASCs characterized by a high level of CD73, CD90, and CD105 express the pluripotent transcription factors OCT4, SOX2, NANOG, and SALL4 under proliferation conditions. A high level of activin A allows for hASCs acquiring the fate of definitive endoderm (DE) cells and expressing the specific transcription factors HEX, FOXA2, SOX17, and GATA4 synchronously. Using a reproducible three-stage method by mimicking liver embryogenesis, hASCs were directed to differentiate into functional hepatocytes. In the first stage, hASCs were induced to become DE cells by 2 days cultured in serum-free medium and 3 days of activin A treatment. Next, the presence of fibroblast growth factor (FGF) 4 and bone morphogenetic protein (BMP) 2 in the medium for 5 days induced efficient hepatic differentiation from DE cells. After 10 days of further maturated by the sequential exposure to hepatocyte growth factor (HGF), oncostatin M (OSM), and dexamethasone (DEX), the hASC-derived hepatocytes expressed mature hepatocytes marker and exhibited functional characterization, including albumin secretion, glycogen storage, urea production, activity of drug transporters, and cytochrome P450 activity. These findings will be useful for the implementation of hASC-derived hepatocytes in therapeutic purposes, metabolic analyses, drug toxicity screening, and studies of hepatocyte function.
人脂肪组织干细胞（hASCs）向肝细胞分化的潜力激发了人们对 hASCs 在治疗应用中可能用途的极大兴趣。了解 hASC 向肝细胞分化的可塑性的分子机制将有助于使这种可能性成为现实。本文中，我们证明了在增殖条件下，高表达 CD73、CD90 和 CD105 的 hASC 同质群体表达多能转录因子 OCT4、SOX2、NANOG 和 SALL4。高水平的激活素 A 允许 hASC 获得明确内胚层（DE）细胞的命运，并同步表达特定的转录因子 HEX、FOXA2、SOX17 和 GATA4。通过模拟肝胚胎发生的可重复的三阶段方法，将 hASC 定向分化为功能性肝细胞。在第一阶段，通过在无血清培养基中培养 2 天和用激活素 A 处理 3 天，将 hASC 诱导成为 DE 细胞。接下来，在培养基中存在成纤维细胞生长因子（FGF）4 和骨形态发生蛋白（BMP）2 的情况下培养 5 天，从 DE 细胞诱导有效的肝分化。在进一步通过顺序暴露于肝细胞生长因子（HGF）、肿瘤坏死因子-α（OSM）和地塞米松（DEX）10 天后成熟后，hASC 衍生的肝细胞表达成熟肝细胞标志物，并表现出功能特征，包括白蛋白分泌、糖原储存、尿素生成、药物转运体活性和细胞色素 P450 活性。这些发现将有助于 hASC 衍生的肝细胞在治疗用途、代谢分析、药物毒性筛选和肝细胞功能研究中的应用。
