Heart Group, Finnish Cardiovascular Research Center and Science Mimicking Life Research Center, Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland.
Adult Stem Cell Group, Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland.
Cells. 2023 Sep 27;12(19):2368. doi: 10.3390/cells12192368.
Induced pluripotent stem cell (iPSC) technology enables differentiation of human hepatocytes or hepatocyte-like cells (iPSC-HLCs). Advances in 3D culturing platforms enable the development of more in vivo-like liver models that recapitulate the complex liver architecture and functionality better than traditional 2D monocultures. Moreover, within the liver, non-parenchymal cells (NPCs) are critically involved in the regulation and maintenance of hepatocyte metabolic function. Thus, models combining 3D culture and co-culturing of various cell types potentially create more functional in vitro liver models than 2D monocultures. Here, we report the establishment of 3D cultures of iPSC-HLCs alone and in co-culture with human umbilical vein endothelial cells (HUVECs) and adipose tissue-derived mesenchymal stem/stromal cells (hASCs). The 3D cultures were performed as spheroids or on microfluidic chips utilizing various biomaterials. Our results show that both 3D spheroid and on-chip culture enhance the expression of mature liver marker genes and proteins compared to 2D. Among the spheroid models, we saw the best functionality in iPSC-HLC monoculture spheroids. On the contrary, in the chip system, the multilineage model outperformed the monoculture chip model. Additionally, the optical projection tomography (OPT) and electrical impedance tomography (EIT) system revealed changes in spheroid size and electrical conductivity during spheroid culture, suggesting changes in cell-cell connections. Altogether, the present study demonstrates that iPSC-HLCs can successfully be cultured in 3D as spheroids and on microfluidic chips, and co-culturing iPSC-HLCs with NPCs enhances their functionality. These 3D in vitro liver systems are promising human-derived platforms usable in various liver-related studies, specifically when using patient-specific iPSCs.
诱导多能干细胞（iPSC）技术可使人类肝细胞或肝样细胞（iPSC-HLC）分化。3D 培养平台的进步使人们能够开发出更接近体内的肝脏模型，这些模型比传统的 2D 单层培养更好地重现复杂的肝脏结构和功能。此外，在肝脏中，非实质细胞（NPC）在调节和维持肝细胞代谢功能方面起着至关重要的作用。因此，将 3D 培养与各种细胞类型的共培养相结合的模型比 2D 单层培养更有可能创建更具功能的体外肝脏模型。在这里，我们报告了单独培养 iPSC-HLC 以及与人脐静脉内皮细胞（HUVEC）和脂肪组织来源的间充质干细胞/基质细胞（hASC）共培养的 3D 培养的建立。3D 培养是作为球体或在利用各种生物材料的微流控芯片上进行的。我们的结果表明，与 2D 相比，3D 球体和芯片培养均能增强成熟肝脏标记基因和蛋白质的表达。在球体模型中，我们在 iPSC-HLC 单层培养球体中看到了最佳的功能。相反，在芯片系统中，多谱系模型的表现优于单核培养芯片模型。此外，光学投影断层扫描（OPT）和电阻抗断层扫描（EIT）系统显示球体培养过程中球体大小和电导率的变化，表明细胞-细胞连接发生变化。总之，本研究表明 iPSC-HLC 可以成功地在 3D 中作为球体和微流控芯片进行培养，并且与 NPC 共培养 iPSC-HLC 可增强其功能。这些 3D 体外肝脏系统是有前途的人类衍生平台，可用于各种与肝脏相关的研究，特别是在使用患者特异性 iPSC 时。
