| 摘要: | 胚胎幹細胞 (ESCs) 在使用時常會遇到道德上的問題，而誘導型多能性幹細胞 (iPSCs) 在培養時常會受到飼養層的汙染。間葉幹細胞 (MSCs) 是一種在臨床上最被廣泛利用的自體幹細胞來源。從羊水中分離出來的幹細胞能夠分化成多種不同的細胞譜系，同時沒有道德上的問題。因此，羊水幹細胞比胚胎幹細胞 (ESCs) 和誘導型多能性幹細胞 (iPSCs) 更適合應用在組織工程以及再生醫學。幹細胞的分化能力以及幹細胞的多能性不只取決於細胞本身，同時也會受到外在環境的影響。因此，使用天然的生物分子 (如細胞外間質) 模仿細胞的微環境，增加幹細胞在體外生長的數量以及調控幹細胞的分化對再生醫學是一件非常重要的研究。 在這篇研究中，我們將羊水幹細胞分別培養在接枝有 gelatin, collagen, fibronectin, laminin, vitronectin和Matrigel 等細胞外間質 (ECM) 的培養皿上，以分析羊水幹細胞與細胞外間質的交互作用。接枝有細胞外間質的培養皿水接觸角大約在40到65度之間，非常適合細胞生長。羊水幹細胞培養在細胞外間質接枝的培養皿上增強了幹細胞分化為成骨細胞的能力。此發現說明了羊水幹細胞在與細胞外間質的交互作用下有助於幹細胞分化為成骨細胞。 在培養皿上改植適合的奈米片段 (細胞外間質) 能夠促進羊水幹細胞分化為成骨細胞。奈米片段的選擇取決於希望幹細胞分化成何種譜系，我們將會討論幹細胞在長時間培養繼代後，哪種細胞外間質能夠維持羊水幹細胞的多能性以及羊水幹細胞的分化能力。Mesenchymal stem cells (MSCs) are one of the most widely available autologous sources of stem cells for clinical applications. Stem cells derived from amniotic fluid are pluripotent fetal cells capable of differentiating into multiple lineages, including representatives of the three embryonic germ layers. Therefore, amniotic fluid may become a more suitable source of stem cells in regenerative medicine and tissue engineering than embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) due to the lack of ethical concerns regarding use of ESCs and the lack of concerns about xenogenic contamination arising from the use of mouse embryonic fibroblasts as a feeder layer for iPSCs. However, stem cell characteristics, such as proper differentiation and maintenance of pluripotency, are regulated not only by the stem cells themselves but also by their microenvironment. Therefore, mimicking stem cell microenvironments using natural biomacromolecules, such as extracellular matrix (ECM) proteins, facilitates the in vitro production of the large numbers of pluripotent stem cells and specifically differentiated cells needed for regenerative medicineIn this study, stem cells from amniotic fluid were cultured for several passages on dishes grafted with extracellular matrix (ECM) or Matrigel where gelatin, collagen, fibronectin, laminin, and vitronectin were selected as ECM components (nanosegments). The effects of interactions between amniotic fluid stem cells and nanosegments were investigated on the expression of pluripotent genes (e.g., Oct4 and Nanog) and on the differentiation abilities of osteoblasts at each passage. The ECM-grafted dishes produced water contact angles from 40 to 65 degrees, which was an adequate water contact angle range for the cell culture. Culture on ECM-immobilized dishes enhances amniotic fluid stem cell differentiation into osteoblasts more than culture on polystyrene dishes grafted with amino groups (PS-NH2 dishes). This finding indicates that specific interactions between amniotic fluid cells and the ECM grafted onto the culture dishes promote the differentiation of cells into osteoblasts. Immobilization of the optimal nanosegments (ECM or Matrigel) onto culture dishes enhances amniotic fluid stem cell differentiation into osteoblasts; the choice of nanosegments depends on the desired differentiated cell type. We will discuss the optimal ECM-grafted dishes, which keep pluripotency of the amniotic fluid stem cells for a long time (i.e., at late passages). |
