Trubert C L, Bernard F, Hivroz C, Carlioz A, Fischer A, Cournot G
CNRS URA 583, Departement d'Anatomie Pathologique, Hôpital Cochin, Paris, France.
Eur J Histochem. 1997;41(3):169-76.
Malignant infantile osteopetrosis is a severe congenital disease characterized by impaired osteoclast activity. Among the multiple factors that influence bone resorption, the c-src protooncogene product pp60c-src plays an essential role, since mice which lack pp60c-src develop osteopetrosis. To gain insight into the possible role of pp60c-csrc in the pathogenesis of infantile osteopetrosis, we examined the osteoclasts of three children displaying the typical features of the disease, aged respectively one, four and seven months. pp60c-csrc expression and localization, together with the expression of a 80/85-kilodalton pp60c-src substrate, cortactin, were examined by immunoelectron microscopy. Osteoclasts from two giant cell tumors were used as controls. Bone and tumor samples were fixed in 4% paraformaldehyde, included in LR-White resin at -30 degrees C and the sections processed with mAb 327 or mAb anti p80/85 by an immunogold technique. pp60c-src was expressed in the cytoplasm, in nuclear membranes and in nuclei of the osteoclasts of the three osteopetrotic children. The subcellular localization of the kinase was not different from the localization in giant tumor cells. In both cases cortactin was abundant. In conclusion, in three children with malignant osteopetrosis, pp60c-src expression in osteoclasts does not appear to be involved in the pathogenesis of the disease. The presence of this protein, however, does not necessarily reflect normal c-src tyrosine kinase activity, nor normal c-src-dependent intracellular signaling pathways. Moreover the presence of the protein in nuclear membranes, and especially around nuclear pores supports the hypothesis that in osteoclasts, c-src may participate in the regulation of RNA processing.
恶性婴儿骨硬化症是一种严重的先天性疾病，其特征为破骨细胞活性受损。在影响骨吸收的多种因素中，原癌基因c-src的产物pp60c-src起着至关重要的作用，因为缺乏pp60c-src的小鼠会发生骨硬化症。为深入了解pp60c-csrc在婴儿骨硬化症发病机制中的可能作用，我们检查了三名分别为1个月、4个月和7个月大、表现出该疾病典型特征的儿童的破骨细胞。通过免疫电子显微镜检查了pp60c-csrc的表达和定位，以及80/85千道尔顿的pp60c-src底物cortactin的表达。来自两个巨细胞瘤的破骨细胞用作对照。将骨和肿瘤样本固定在4%多聚甲醛中，于-30℃包埋在LR-White树脂中，并用免疫金技术用单克隆抗体327或抗p80/85单克隆抗体处理切片。pp60c-src在三名患骨硬化症儿童的破骨细胞的细胞质、核膜和细胞核中均有表达。该激酶的亚细胞定位与巨细胞瘤细胞中的定位没有差异。在这两种情况下，cortactin都很丰富。总之，在三名患有恶性骨硬化症的儿童中，破骨细胞中pp60c-src的表达似乎与该疾病的发病机制无关。然而，这种蛋白质的存在不一定反映正常的c-src酪氨酸激酶活性，也不一定反映正常的c-src依赖性细胞内信号通路。此外，该蛋白质在核膜中尤其是核孔周围的存在支持了这样一种假说，即在破骨细胞中，c-src可能参与RNA加工的调节。
