人類牙髓幹細胞是獨特的間葉幹細胞，具有自我更新與多譜系分化的能力。 Oct4與Nanog 屬於複效性基因。本研究的目的欲檢測牙髓幹細胞中 Oct4與Nanog 基因表現所致之細胞生理功能。於本研究中，利用慢病毒轉殖基因方法，調控牙髓幹細胞 Oct4/Nanog基因共同減弱或共同過度表現，以審視Oct4與Nanog基因表現於間葉幹細胞特性中所扮演的角色。間葉幹細胞具有成骨、成軟骨與成脂肪誘導性分化能力，此乃利用定量即時反轉錄-聚合酶連鎖反應檢測其成骨性、成軟骨性與成脂肪性細胞標誌表現程度而得知。首先，觀察到細胞標誌Stro-1與CD146皆為陽性的牙髓細胞，其Oct4與Nanog基因表現經調升後，其間葉幹細胞特性比細胞標誌Stro-1與CD146皆為陰性的牙髓細胞更明顯。調降牙髓幹細胞Oct4與Nanog基因共同表現會明顯地降低其細胞增殖、成骨性分化能力、Stro-1、CD146細胞標誌與鹼性磷酸酶的活性。反之，Oct4與Nanog基因共同過度表現會加強Stro-1與CD 146細胞標誌的表現程度、增殖速率、成骨、成軟骨與成脂肪誘導性分化能力以及成骨、成軟骨與成脂肪誘導性分化細胞標誌的表現程度。因此，在維持人類牙髓幹細胞特性上，Oct4與Nanog 的訊息傳遞應具有調控樞紐的功能。
Human dental pulp stem cells (DPSCs), unique mesenchymal stem cells (MSCs) type, exhibit the characteristics of self-renewal and multi-lineage differentiation capacity. Oct4 and Nanog are pluripotent genes. The aim of this study was to determine the physiological functions of Oct4 and Nanog expression in DPSCs. Herein, we determined the critical role of Oct4 and Nanog axis modulating MSCs properties of DPSCs by lentiviral-mediated co-knockdown or co-overexpression of Oct4 and Nanog in DPSCs. MSCs properties including osteogenic / chondrogenic / adipogenic induction differentiation was assayed for expression of osetogenic / chondrogenic / adipogenic markers by quantitative real-time RT-PCR analysis. Initially, we observed that the expression profile of Oct4 and Nanog in Stro-1(＋) / CD146(＋) dental pulp cells, which exerted properties of MSCs, was significantly up-regulated compared to that of Stro-1(－) / CD146(－) dental pulp cells. Down-regulation of Oct4 and Nanog co-expression significantly reduced the cell proliferation, osteogenic differentiation capability, Stro-1, CD 146, and Alkaline phosphatase (ALP) activity of DPSCs. In contrast, co-overexpression of Oct4 and Nanog enhanced the proliferation rate , expression level of Stro-1 and CD146, and osteogenic / chodrogenic / adipogenic induction differentiation capability, and expression of osteogenic / chondrogenic / adipogenic induction differentiation markers. Our results suggest that Oct4 and Nanog signaling is a regulatory switch to maintain properties in DPSCs.
