Thy-1-positive cells in the subodontoblastic layer possess high potential to differentiate into hard tissue-forming cells
Thy-1-positive cells in the subodontoblastic layer possess high potential to differentiate into hard tissue-forming cells
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DOI：
10.1007/s00418-012-0928-1
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发表时间：
2012-06-01
影响因子：
2.3
通讯作者：
Nakamura, Hiroaki
中科院分区：
文献类型：
--
作者：
Hosoya, Akihiro;Hiraga, Toru;Nakamura, Hiroaki
牙髓中富含成牙本质细胞层的细胞可能含有成牙本质细胞前体细胞，因为它们与成牙本质细胞的位置关系以及它们的高碱性磷酸酶(ALP)活性。然而，目前尚未确定这些细胞是否具有分化为成牙本质细胞的能力。在本研究中，我们首次发现亚母细胞层中的大多数细胞表达Thy-1，这是一种干细胞和祖细胞的细胞表面标志。然后，我们利用荧光激活的细胞分选器从大鼠牙髓细胞中分离出高表达和低表达的Thy-1细胞(Thy-1(高)和Thy-1(低))，并在体内外评价其向硬组织形成细胞分化的能力。与Thy-1(低)细胞相比，经骨形态发生蛋白-2刺激后，Thy-1(高)细胞的碱性磷酸酶(ALP)活性和茜素红阳性矿化基质的形成明显加快。此外，Thy-1(高)细胞皮下移植可有效诱导骨样基质的形成。这些结果提示，定位于亚成牙本质层的Thy-1阳性牙髓细胞具有向硬组织形成细胞分化的能力，因此这些细胞可能是成牙本质细胞的来源。
The cells of the subodontoblastic cell-rich layer in dental pulp are speculated to contain odontoblast progenitor cells because of their positional relationship with odontoblasts as well as their high alkaline phosphatase (ALP) activity. However, it has yet to be determined whether these cells have the ability to differentiate into odontoblastic cells. In the present study, we firstly found that the majority of cells in the subodontoblastic layer expressed Thy-1, a cell-surface marker of stem and progenitor cells. Then, we evaluated the capacity of Thy-1 high- and low-expressing (Thy-1(high) and Thy-1(low)) cells separated from rat dental pulp cells by use of a fluorescence-activated cell sorter to differentiate into hard tissue-forming cells in vitro and in vivo. Following stimulation with bone morphogenetic protein-2, Thy-1(high) cells in vitro showed accelerated induction of ALP activity and formation of alizarin red-positive mineralized matrix compared with Thy-1(low) cells. Furthermore, subcutaneous implantation of Thy-1(high) cells efficiently induced the formation of bone-like matrix. These results collectively suggest that Thy-1-positive dental pulp cells localized in the subodontoblastic layer had the ability to differentiate into hard tissue-forming cells, and thus these cells may serve as a source of odontoblastic cells.