MOLECULAR MECHANISMS OF MACROPHAGE MULTINUCLEATION

破骨细胞和多核巨细胞来源于融合。 单核巨噬细胞系的单核前体细胞。 多核化是这些细胞的主要表型特征之一。 细胞。尽管核聚变是形成它们的关键一步 细胞，其发生的分子机制，以及功能 人们对多核化的后果知之甚少。破骨细胞和 巨细胞有一些相似之处，但显然是不同的细胞类型 并生活在不同的微环境中。就他们的 相似之处在于，我们已经证明了多核肺泡 巨噬细胞像破骨细胞一样，表达一种高度极化的 质膜Na，K-ATPase的浓度和高拷贝 降钙素受体的数量。最重要的是，它一直是 最近证明，肺泡巨噬细胞，在 在适当的条件下，能够在体外吸收骨。在……里面 这个应用我们建议使用巨噬细胞作为模型系统来 单核-巨噬细胞融合机制的研究 血统。 为了研究细胞融合的机制，我们假设 多核细胞的形成必须依赖于细胞表面分子 专用于单核巨噬细胞。 在之前的资助期间，我们发现了巨噬细胞- 潜在地调节融合的特定表面分子。我们有 产生的单克隆抗体因其预防能力而被挑选出来 巨噬细胞的体外融合。初步的生化特征- 其中一种抗原的表面糖蛋白已经显露出来。 它是在巨噬细胞中特异性检测到的 核聚变。检测到一种类似分子量的糖蛋白 另外三种单抗，我们也选择了它们 防止核聚变的能力。 该项目的长期目标是阐明融合机制。 巨噬细胞，导致多核细胞的形成。 本申请的具体目的是： 1.在分子水平上表征化合物的结构 我们的单抗12D6、10B11、10C4和 10C5能在体外阻断巨噬细胞融合。这将会实现的 通过克隆编码相应抗原的cDNA。 2.建立适合功能基因表达的细胞表达系统 对这些抗原的分析。 3.确定12D6抗原在破骨细胞和巨细胞中的作用 在体内形成，以及通过药物对其表达的调节 影响破骨细胞分化。

Osteoclasts and multinucleated giant cells originate from the fusion of mononuclear precursors of the monocyte-macrophage lineage. Multinucleation is one of the main phenotypic characteristics of these cells. Although fusion is an essential step in formation of these cells, the molecular mechanisms by which it occurs, and the functional consequences of multinucleation are poorly understood. Osteoclast and giant cells share some similarities but are clearly distinct cell types and reside in different microenvironments. As far as their similarities are concerned, we have shown that multinucleated alveolar macrophages express, like osteoclasts, a high and polarized concentration of plasma membrane Na,K-ATPases as well as a high copy number of receptors for calcitonin. Most importantly, it has been recently demonstrated that alveolar macrophages, cultured under appropriate conditions, are capable of resorbing bone in vitro. In this application we propose to use macrophages as a model system to study the mechanism of fusion of cells of the monocyte- macrophage lineage. To investigate the mechanism of cell fusion, we hypothesize that the formation of polykaryons must depend upon cell surface molecules specific for monocyte-macrophages. During the previous funding period, we have identified macrophage- specific surface molecules which potentially mediate fusion. We have generated monoclonal antibodies selected for their ability to prevent fusion of macrophages in vitro. Preliminary biochemical character- ization of one of the antigens has revealed a surface glycoprotein which is specifically detected in macrophages at the time of their fusion. A glycoprotein of similar molecular weight is detected by three additional monoclonal antibodies which we also selected for their ability to prevent fusion. The long-term goal of this project is to elucidate the fusion mechanism of macrophages which leads to the formation of polykaryons. The SPECIFIC AIMS of the present application are: 1. To characterize at the molecular level the structure of the antigens recognized by our monoclonal antibodies 12D6, 10B11, 10C4 and 10C5 which block macrophage fusion in vitro. This will be accomplished by cloning cDNAs coding for the corresponding antigens. 2. To establish a suitable cell expression system for the functional analysis of these antigens. 3. To determine the role of 12D6 antigen in osteoclast and giant cell formation in vivo, and the regulation of its expression by agents that affect osteoclast differentiation.