In vitro apatite induction by osteopontin:: Interfacial energy for hydroxyapatite nucleation on osteopontin
In vitro apatite induction by osteopontin:: Interfacial energy for hydroxyapatite nucleation on osteopontin
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DOI：
10.1002/jbm.a.20066
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发表时间：
2004-04-01
影响因子：
4.9
通讯作者：
Amano, K
中科院分区：
文献类型：
--
作者：
Ito, S;Saito, T;Amano, K
与 I 型胶原相互作用的非胶原磷蛋白被认为使矿物相成核到矿化组织的胶原原纤维网络中。我们之前报道过，一种特定的牙本质磷蛋白（磷酸蛋白）与不溶性基质（如 I 型胶原原纤维）交联，是一种有效的磷灰石成核剂。在这项研究中，我们研究了牙本质中另一种磷蛋白——骨桥蛋白在体外磷灰石成核的能力。从牛奶中纯化的骨桥蛋白被吸附到琼脂糖珠上或交联到琼脂糖珠上。每种制剂均在亚稳态溶液中于 37°C 下孵育。磷灰石是由与琼脂糖珠交联的骨桥蛋白诱导的，而吸附到琼脂糖珠上的骨桥蛋白未能诱导磷灰石晶体形成。使用经典成核理论，骨桥蛋白与琼脂糖珠交联的羟基磷灰石成核的界面能被确定为94.7 ergs /cm(2)。该值大于磷磷灰石的值，但与羟基磷灰石的值相似。本研究表明，骨桥蛋白与磷酸蛋白一样，当其在体外与某些底物共价结合时，具有很高的诱导磷灰石形成的潜力，并表明骨桥蛋白与 I 型胶原蛋白结合可能在体内诱导磷灰石形成。 (C) 2004 年 Wiley 期刊公司。
Noncollagenous phosphoproteins that interact with type I collagen are thought to nucleate the mineral phase to the collagen fibril network of mineralized tissues. We previously reported that a specific dentin phosphoprotein, phosphophoryn, crosslinked to an insoluble substrate such as type I collagen fibrils, was an effective nucleator of apatite. In this study, we investigated the capacity of another phosphoprotein in dentin, osteopontin, for apatite nucleation in vitro. Osteopontin purified from bovine milk was either absorbed to agarose beads or crosslinked to agarose beads. Each preparation was incubated at 37degreesC in metastable solutions. Apatite was induced by osteopontin that was crosslinked to agarose beads, whereas osteopontin adsorbed to agarose beads failed to induce apatite crystal formation. Using classical nucleation theory, the interfacial energy for hydroxyapatite nucleation on osteopontin crosslinked to agarose beads was determined to be 94.7 ergs /cm(2). This value is larger than that for phosphophoryn, though it is similar to that for hydroxyapatite. The present study indicates that osteopontin, like phosphophoryn, has a high potential to induce apatite formation when it is covalently bound to some substrate in vitro, and suggests the possibility that osteopontin bound to type I collagen may induce apatite formation in vivo. (C) 2004 Wiley Periodicals, Inc.