Center for Stem Cell Biology and Engineering, University of California, Santa Barbara, California 93106, USA.
Stem Cells Dev. 2010 Aug;19(8):1231-40. doi: 10.1089/scd.2009.0328.
Human induced pluripotent stem cells (iPSCs) hold promise as a source of adult-derived, patient-specific pluripotent cells for use in cell-based regenerative therapies. However, current methods of cell culture are tedious and expensive, and the mechanisms underlying cell proliferation are not understood. In this study, we investigated expression and function of iPSC integrin extracellular matrix receptors to better understand the molecular mechanisms of cell adhesion, survival, and proliferation. We show that iPSC lines generated using Oct-3/4, Sox-2, Nanog, and Lin-28 express a repertoire of integrins similar to that of hESCs, with prominent expression of subunits alpha5, alpha6, alphav, beta1, and beta5. Integrin function was investigated in iPSCs cultured without feeder layers on Matrigel or vitronectin, in comparison to human embryonic stem cells. beta1 integrins were required for adhesion and proliferation on Matrigel, as shown by immunological blockade experiments. On vitronectin, the integrin alphavbeta5 was required for initial attachment, but inhibition of both alphavbeta5 and beta1 was required to significantly decrease iPSC proliferation. Furthermore, iPSCs cultured on vitronectin for 9 passages retained normal karyotype, pluripotency marker expression, and capacity to differentiate in vitro. These studies suggest that vitronectin, or derivatives thereof, might substitute for Matrigel in a more defined system for iPSC culture.
人诱导多能干细胞（iPSCs）有望成为一种成人来源的、患者特异性的多能细胞来源，用于基于细胞的再生治疗。然而，目前的细胞培养方法繁琐且昂贵，细胞增殖的机制尚不清楚。在这项研究中，我们研究了 iPSC 整合素细胞外基质受体的表达和功能，以更好地理解细胞黏附、存活和增殖的分子机制。我们发现，使用 Oct-3/4、Sox-2、Nanog 和 Lin-28 生成的 iPSC 系表达了与 hESCs 相似的整合素谱，其中亚基 alpha5、alpha6、alphav、beta1 和 beta5 的表达较为突出。我们在没有饲养层的情况下，在 Matrigel 或 vitronectin 上培养 iPSC，并与人类胚胎干细胞进行比较，研究了整合素的功能。免疫阻断实验表明，beta1 整合素对于在 Matrigel 上的黏附和增殖是必需的。在 vitronectin 上，整合素 alphavbeta5 对于初始附着是必需的，但抑制 alphavbeta5 和 beta1 都显著降低了 iPSC 的增殖。此外，在 vitronectin 上培养 9 代的 iPSCs 保留了正常的核型、多能性标记物表达和体外分化的能力。这些研究表明，vitronectin 或其衍生物可能替代 Matrigel，用于 iPSC 培养的更明确系统。
