Rolo of Osteoblastic Cells in Osteoclast Development.

(1)基质细胞系在体外支持破骨细胞形成的研究我们以前报道过，在小鼠脾细胞和从小鼠颅骨分离的成骨细胞共培养中，破骨细胞样多核细胞（MNCs）在1alpha， 25 (OH) _2D_3的响应下形成（内分泌学，123:26,1988）。在这项研究中，我们研究了在诱导破骨细胞样MNC形成过程中，这种原代成骨细胞是否可以被已建立的细胞系所取代。两种骨髓来源的基质细胞系MC3T3-G2/PA6和ST2在与脾细胞共培养时支持破骨细胞样MNC的形成。此外，从小鼠颅骨中建立了一种新的基质细胞系（KS4），该细胞系支持在共培养中形成破骨细胞样MNC。在长期培养中，KS4细胞表现出典型的成骨细胞表型，如强碱性磷酸酶活性，pth依赖性cAMP产生和结节形成。(2)破骨细胞的来源我们利用与ST2细胞共培养的系统考察了破骨细胞的来源。在ST2细胞存在下，不仅骨髓中的未成熟造血细胞，外周血中的单核细胞和肺泡组织中的巨噬细胞也分化为破骨细胞样MNCs。这表明破骨细胞属于单核-巨噬细胞家族。(3)集落刺激因子（colony stimulating factors, csf）对破骨细胞发育的影响我们检测了IL-3、GM-CSF、M-CSF、G-CSF对破骨细胞祖细胞增殖和分化的影响。没有一种csf刺激祖细胞分化为破骨细胞样跨国细胞。然而，csf，特别是M-CSF，明显刺激祖细胞的增殖。最近在M-CSF基因的编码区发现了骨增生（op/op）小鼠的突变。这表明op/op小鼠的破骨细胞缺乏是由于功能性M-CSF的产生失败。我们使用共混系统检测了op/op小鼠破骨细胞的形成。我们发现op/op小鼠成骨细胞与正常脾细胞共培养时不支持破骨细胞的形成。在共培养物中加入M-CSF可诱导破骨细胞样细胞的出现。这些结果表明，成骨细胞产生的M-CSF对破骨细胞的发育至关重要。少

(1) Studies on stromal cell lines which support osteoclast formation in vitroWe previously reported that osteoclast-like multinucleated cells (MNCs) were formed in response to 1alpha, 25 (OH) _2D_3 in co-cultures of mouse spleen cells and osteoblastic cells freshly isolated from mouse calvariae (Endocrinology, 123 : 2600, 1988). In this study, we examined whether such primary osteoblastic cells can be replaced by established cell lines in inducing osteoclast-like MNC formation. Two bone marrow-derived stromal cell line, MC3T3-G2/PA6 and ST2, were found to suppoort osteoclast-like MNC formation in the co-culture with spleen cells. In addition, a new stromal cell line (KS4), which supports osteoclast-like MNC formation in the co-cultures, was established from mouse calvariae. KS4 cells exhibited typical phenotypes of osteoblasts such as intense alkaline phophatase activity, PTH-dependent cAMP production, and nodule formation in a long-term culture.(2) Origin of osteoclastsWe examined the … More origin of osteoclasts using the co-culture system with ST2 cells. Not only immature hematopoietic cells in bone marrow but also monocytoes in peripheral blood and macrophages in alveolar tissues differentiated into osteoclast-like MNCs in the presence of ST2 cells. This indicates that osteoclasts are the cells of the monocyte-macrophage family.(3) Effects of colony stimulating factors (CSFs) on osteoclast developmentWe examined the effects of CSFs (IL-3, GM-CSF, M-CSF, G-CSF) on the proliferation and the differentiation of osteoclast progenitors. None of the CSFs stimulated differentiation of the progenitors into osteoclast-like MNCs. However, the CSFs, especially M-CSF, markedly stimulated proliferation of the progenitors.The mutation of osteopetrotic (op/op) mice was recently found in the coding region of the M-CSF gene. This indicates that osteoclast deficiency in op/op mice is due to failure of the production of functional M-CSF. We examined osteoclast formation in op/op mice using the co-colture system. We found that osteoblastic cells from op/op mice did not support osteoclast formation in the co-cultures with normal spleen cells. Adding M-CSF to the co-cultures induced the appearance of osteoclast-like cells. These results indicate that M-CSF produced by osteoblastic cells is essential for osteoclast development. Less