Taylor L M, Turksen K, Aubin J E, Heersche J N
Medical Research Council Group in Periodontal Physiology, Faculty of Dentistry, University of Toronto, Ontario, Canada.
Endocrinology. 1993 Nov;133(5):2292-300. doi: 10.1210/endo.133.5.7691585.
Previous reports have demonstrated that hemopoietic progenitor cells derived from mouse bone marrow can form osteoclast-like cells when cultured in the presence of stromal cells and 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]. We show here that in cocultures of mouse bone marrow cells and a clonal chondrogenic cell line (C5.18), a stimulation of the number of tartrate-resistant acid phosphatase-positive (TRAP+) colonies is seen with or without the addition of 1,25-(OH)2D3 to the cultures. A large proportion of the TRAP+ cells had calcitonin receptors. In addition resorption lacunae were observed on bone slices on which cocultures were maintained, thus these cells had the characteristics of osteoclasts. The number of osteoclast-containing colonies that formed in cocultures varied with the plating density of the C5.18 cells and the length of time the C5.18 cells were cultured before adding mouse bone marrow. These results suggested that osteoclast differentiation decreased with increasing cartilage differentiation. C5.18 cells treated with 1,25-(OH)2D3 before coculture stimulated TRAP+ osteoclast colony formation to a greater extent than untreated C5.18 cells, whereas C5.18 cells cultured in the presence of dexamethasone before coculture inhibited TRAP+ osteoclast colony formation relative to untreated C5.18 cells. Since 1,25-(OH)2D3 inhibits and dexamethasone stimulates cartilage differentiation in C5.18 cells, these results agree with the view that chondroprogenitor cells stimulate osteoclast colony formation, whereas cultures containing predominantly mature chondrocytes do not. Osteoclast-containing colonies were frequently associated with colonies of alkaline phosphatase-positive (AP+) cells. This raised the possibility that C5.18 cells stimulated osteoclast differentiation indirectly by increasing the numbers of AP+ stromal cells from the marrow population, which in turn could stimulate osteoclast differentiation from marrow hemopoietic progenitors. In cocultures in which the C5.18 cells were physically separated from the marrow cells, we also observed increased numbers of TRAP+ colonies growing in association with large colonies of AP+ cells, suggesting that C5.18 cells release a soluble factor that mediates these effects.
先前的报告表明，从小鼠骨髓中分离出的造血祖细胞在基质细胞和1,25 - 二羟基维生素D3 [1,25-(OH)2D3]存在的情况下培养时，可以形成破骨细胞样细胞。我们在此表明，在小鼠骨髓细胞与克隆软骨生成细胞系（C5.18）的共培养物中，无论培养物中是否添加1,25-(OH)2D3，抗酒石酸酸性磷酸酶阳性（TRAP+）集落的数量都会增加。大部分TRAP+细胞具有降钙素受体。此外，在维持共培养的骨切片上观察到吸收陷窝，因此这些细胞具有破骨细胞的特征。共培养中形成的含破骨细胞集落的数量随C5.18细胞的接种密度以及添加小鼠骨髓前C5.18细胞的培养时间而变化。这些结果表明，破骨细胞分化随着软骨分化的增加而减少。共培养前用1,25-(OH)2D3处理的C5.18细胞比未处理的C5.18细胞更能刺激TRAP+破骨细胞集落的形成，而共培养前在地塞米松存在下培养的C5.18细胞相对于未处理的C5.18细胞抑制TRAP+破骨细胞集落的形成。由于1,25-(OH)2D3抑制而地塞米松刺激C5.18细胞中的软骨分化，这些结果与软骨祖细胞刺激破骨细胞集落形成而主要含有成熟软骨细胞的培养物则不然的观点一致。含破骨细胞的集落经常与碱性磷酸酶阳性（AP+）细胞的集落相关联。这增加了一种可能性，即C5.18细胞通过增加来自骨髓群体的AP+基质细胞的数量间接刺激破骨细胞分化，而这些AP+基质细胞反过来又可以刺激骨髓造血祖细胞分化为破骨细胞。在C5.18细胞与骨髓细胞物理分离的共培养物中，我们还观察到与大的AP+细胞集落相关联生长的TRAP+集落数量增加，这表明C5.18细胞释放一种可溶性因子来介导这些效应。
