Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, USA.
Biotechnol Bioeng. 2011 Feb;108(2):364-75. doi: 10.1002/bit.22939.
Many applications of stem cell technologies require a large quantity of cells for which scalable processes of cell expansion and differentiation are essential. Multipotent adult progenitor cells (MAPCs) are adult stem cells isolated from the bone marrow with extensive self-renewal and broad differentiation capabilities. MAPCs are typically cultured surface adherent (2D) and at low cell density, making the large surface required for cell expansion a hindrance for many applications. This study demonstrates that MAPCs can be cultivated as aggregates in an undifferentiated state for at least 16 days, as levels of a number of transcripts, including Oct4, remained similar, Oct4 protein was unchanged, and differentiation to neural progenitor, endothelial cell and hepatocyte like cells was retained. Cultivation of these aggregates in stirred bioreactor lead to a 70-fold expansion in 6 days with final cell densities of close to 10⁶/mL. Importantly, the MAPC aggregates recovered from stirred bioreactors could be differentiated to hepatocyte-like cells that expressed albumin, alpha-1-antitrypsin (AAT), and tyrosine amino transferase (TAT) transcripts and also secreted albumin and urea. This method of scalable expansion combined with differentiation of MAPCs can potentially be used for generating large numbers of MAPC and MAPC-derived differentiated cells.
许多干细胞技术的应用都需要大量的细胞，因此需要可扩展的细胞扩增和分化工艺。多能成体祖细胞（MAPC）是从骨髓中分离出来的成体干细胞，具有广泛的自我更新和广泛的分化能力。MAPC 通常在低细胞密度下以表面贴壁（2D）方式培养，这使得细胞扩增所需的大表面积成为许多应用的障碍。本研究表明，MAPC 可以作为未分化的聚集体培养至少 16 天，因为包括 Oct4 在内的许多转录本的水平保持相似，Oct4 蛋白不变，并且能够分化为神经祖细胞、内皮细胞和肝样细胞。将这些聚集体在搅拌式生物反应器中培养可在 6 天内实现 70 倍的扩增，最终细胞密度接近 10⁶/mL。重要的是，从搅拌式生物反应器中回收的 MAPC 聚集体可以分化为表达白蛋白、α-1-抗胰蛋白酶（AAT）和酪氨酸氨基转移酶（TAT）转录本的肝样细胞，并且还分泌白蛋白和尿素。这种可扩展的 MAPC 扩增和分化方法可用于生成大量的 MAPC 和 MAPC 衍生的分化细胞。
