Iba K, Sawada N, Nuka S, Chiba H, Obata H, Isomura H, Satoh M, Ishii S, Mori M
Department of Pathology, Sapporo Medical University School of Medicine, Japan.
Bone. 1996 Oct;19(4):363-9. doi: 10.1016/s8756-3282(96)00216-5.
A human osteoblastic cell line (SV-HFO) established in our laboratory expresses osteoblastic markers, including mineralization in vitro, in response to differentiation-inducing agents such as dexamethasone. In this study, we examined the effects of transforming growth factor beta 1 (TGF-beta 1) on the mineralization of SV-HFO cells and show that TGF-beta 1 inhibited the mineralization of the cells via down regulation of tetranectin and alkaline phosphatase without influencing other osteoblastic markers. To examine precisely the effects of TGF-beta 1 on the process of mineralization, we tentatively divided the whole process of mineralization into four phases: induced ALP activity (days 0-5), maximal ALP activity (days 5-10), early mineralization (days 10-15), and progressive mineralization (days 15-20). These inhibitory effects of TGF-beta 1 on the expression of tetranectin and alkaline phosphatase, like that on mineralization, were observed only when TGF-beta 1 was applied in the early phase of the process of mineralization. On the other hand, the other osteoblastic markers were not influenced by treatment with TGF-beta 1. These results suggest that TGF-beta 1 may inhibit mineralization of osteoblasts by the downregulation of tetranectin and alkaline phosphatase expression in the early phase. Thus, TGF-beta 1 has phase-dependent effects on a human osteoblastic cell line during the process of mineralization.
我们实验室建立的人成骨细胞系（SV-HFO）表达成骨细胞标志物，包括在体外对诸如地塞米松等诱导分化剂作出反应而矿化。在本研究中，我们检测了转化生长因子β1（TGF-β1）对SV-HFO细胞矿化的影响，结果表明TGF-β1通过下调纤连蛋白和碱性磷酸酶来抑制细胞矿化，而不影响其他成骨细胞标志物。为了精确检测TGF-β1对矿化过程的影响，我们暂时将矿化的整个过程分为四个阶段：诱导碱性磷酸酶活性（第0 - 5天）、最大碱性磷酸酶活性（第5 - 10天）、早期矿化（第10 - 15天）和进行性矿化（第15 - 20天）。TGF-β1对纤连蛋白和碱性磷酸酶表达的这些抑制作用，与对矿化的抑制作用一样，仅在矿化过程的早期阶段应用TGF-β1时才观察到。另一方面，其他成骨细胞标志物不受TGF-β1处理的影响。这些结果表明，TGF-β1可能通过在早期阶段下调纤连蛋白和碱性磷酸酶的表达来抑制成骨细胞的矿化。因此，在矿化过程中，TGF-β1对人成骨细胞系具有阶段依赖性作用。
