細胞表面的接受器CD44在牙齒的發育中扮演重要的角色。然而，CD44對於牙髓細胞的礦化作用，目前仍然不明朗。CD44的主要配體—透明質酸(HA)，在細胞分化扮演主導的作用。我們假設添加高分子量的透明質酸會誘導成牙本質細胞分化。使用不同劑量的透明質酸處理牙髓細胞，在3~14天後評估對鹼性磷酸酶活性的影響。透明質酸對牙髓細胞的礦物質沉積能力，則利用基質礦化小體染色檢驗。為了確認與牙齒礦化相關的基因，我們培養三天以後比較正常培養與添加玻尿酸的組別，並且利用PCR array的方式找出礦物質化相關的基因。之後弱化(knockdown) CD44，以相同方式培養，利用及時定量聚合酶連鎖反應、西方點墨法以及免疫組織染色法以研究牙髓細胞中COL15A1,BMP7和ALPL mRNA和蛋白質的表現，驗證PCR array的實驗結果。

實驗結果顯示在培養液當中添加透明質酸(1500~1800 kDa)測試鹼性磷酸酶的活性，在第3天的時間點，相較其他組別增加。PCR array的實驗結果可以看到添加高分子量透明質酸的組別相較於控制組有顯著的增加，成骨相關的基因，例如：COL15A1, IBSP, BMP7 以及ALPL，有高度表現。利用免疫組織化學染色法檢驗CD44, COL15A1, BMP7 以及ALPL是否表現於造牙本質細胞層。
我們的結果分析指出高分子量的透明質酸可以做為一個良好的材料，在早期的培養刺激牙髓細胞礦物質化。我們推測透明質酸所介導CD44的礦物質化，ALPL以及BMP7可能參與其中。

CD44 has been suggested to play an important role during tooth development. However, little emphasis has been placed on whether the CD44 can influence mineralization of dental pulp cells. One major ligand for CD44 is hyaluronan (HA), which plays an important role in cell differentiation. We hypothesized that HA with high molecular weight at optimal concentration may induce odontoblastic differentiation. We added different doses for high molecular weight of HA to the medium at the first plating of cells. After 3 to 14 days in culture, cell differentiation was evaluated by alkaline phosphatase activity. The effects of HA on mineral deposition were examined using Alizarin red staining. To identify the genes that are involved in dental mineralization, we compared the expression of normal α-MEM and α-MEM with additive HA (2 mg/ml) in 3 days by osteogenesis PCR array. Then, PCR array was used to identify the upregulated osteogenesis-associated genes. The CD44 knockdown cells and control cells were cultured in α-MEM with additive HA (2 mg/ml) for 3 days. Q-PCR, immunoblotting, and immunohistochemistry analysis were used to investigate the mRNA and protein expression profiles of COL15A1, BMP7 and ALPL in the dental pulp cells to confirm PCR array results.
The results showed that treatment with high molecular weight (1500~1800 kDa) HA in early cultures (days3) increased alkaline phosphatase activity. On the other hand, high molecular weight HA in basal medium, significantly increased mineralization in the dental pulp cells cultures. The data of osteogenesis PCR array and Q-PCR identifed several up-regulated osteogenesis-associated genes, including COL15A1, IBSP, BMP7 and ALPL. IHC staining with CD44, BMP7, ALPL and COL15A1 was applied to check if all markers had expressed on the odontoblast layer.
Our analysis indicated that high molecular-weight HA maybe a good material to stimulate dental mineralization in early cultures. We hypothesize that hyaluronic acid signals at least in part through CD44 to regulate dental mineralization, with involvement of ALPL and BMP7.

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