Mikuni-Takagaki Y, Kakai Y, Satoyoshi M, Kawano E, Suzuki Y, Kawase T, Saito S
Department of Oral Biochemistry, Kanagawa Dental College, Yokosuka, Japan.
J Bone Miner Res. 1995 Feb;10(2):231-42. doi: 10.1002/jbmr.5650100209.
Osteocyte-like cells were prepared by sequentially treating calvaria from newborn rats with collagenase and chelating agents. On a reconstituted gel of basement membrane components, cells from the third collagenase digest displayed a round shape and expressed the highest level of alkaline phosphatase with minimal osteocalcin deposition into the matrix. On the other hand, cells derived from the interior after EDTA treatment exhibited well-developed dendritic cell processes and expressed essentially no alkaline phosphatase. The latter population also showed quite distinct characteristics such as higher extracellular activities of casein kinase II and ecto-5'-nucleotidase and the extracellular accumulation of a large amount of osteocalcin associated with mineral. These diverse phenotypic and protein expressions as well as the sites from which each population of cells were recovered strongly suggest that we have isolated osteoblastic and osteocytic cells. Bone sialoprotein II was extracellularly phosphorylated by casein kinase II in osteocytic cells but not in osteoblastic cells. We discuss the possibility that differentiation of young osteocytes from osteoblasts may facilitate the biochemical sequence of mineral deposition in the bone matrix.
通过用胶原酶和螯合剂依次处理新生大鼠的颅骨来制备类骨细胞。在基底膜成分的重组凝胶上，第三次胶原酶消化得到的细胞呈圆形，碱性磷酸酶表达水平最高，且骨钙素在基质中的沉积最少。另一方面，经乙二胺四乙酸（EDTA）处理后从内部获得的细胞呈现出发育良好的树突状细胞突起，且基本不表达碱性磷酸酶。后一组细胞还表现出相当明显的特征，如酪蛋白激酶II和胞外5'-核苷酸酶的细胞外活性较高，以及与矿物质相关的大量骨钙素在细胞外积累。这些不同的表型和蛋白质表达以及回收每组细胞的部位有力地表明，我们已经分离出了成骨细胞和骨细胞。骨唾液蛋白II在骨细胞中被酪蛋白激酶II细胞外磷酸化，但在成骨细胞中则不会。我们讨论了成骨细胞向年轻骨细胞的分化可能促进骨基质中矿物质沉积生化序列的可能性。
