Lomri A, Marie P J
Unité 18 INSERM, Hôpital Lariboisière, France.
Bone. 1990;11(6):445-51. doi: 10.1016/8756-3282(90)90141-k.
Transforming growth factor beta (TGF beta) has been shown to influence the growth and differentiation of many cell types in vitro. We have examined the effects of TGF beta on cell morphology and cytoskeletal organization in relation to parameters of cell proliferation and differentiation in endosteal osteoblastic cells isolated from mouse caudal vertebrae. Treatment of mouse osteoblastic cells cultured in serum free medium for 24 hours with TGF beta (1.5-30 ng/mL) slightly (-23%) inhibited alkaline phosphatase activity. In parallel, TGF beta (0.5-30 ng/mL, 24 hours) greatly increased cell replication as evaluated by [3H]-thymidine incorporation into DNA (157% to 325% of controls). At a median dose (1.5 ng/mL) that affected both alkaline phosphatase and DNA synthesis (235% of controls) TGF beta induced rapid (six hours) cell respreading of quiescent mouse osteoblastic cells. This effect was associated with increased polymerization of actin, alpha actinin, and tubulins, as evaluated by both biochemical and immunofluorescence methods. In addition, TGF beta (1.5 ng/mL) increased the de novo biosynthesis of actin, alpha actinin, vimentin, and tubulins, as determined by [35S] methionine labeling and fractionation of cytoskeletal proteins using two-dimensional gel electrophoresis. These effects were rapid and transient, as they occurred at six hours and were reversed after 24 hours of TGF beta exposure. The results indicate that the stimulatory effect of TGF beta on DNA synthesis in endosteal mouse osteoblastic cells is associated with a transient increase in cell spreading associated with enhanced polymerization and synthesis of cytoskeletal proteins.
转化生长因子β（TGFβ）已被证明在体外可影响多种细胞类型的生长和分化。我们研究了TGFβ对从小鼠尾椎分离的骨内膜成骨细胞的细胞形态和细胞骨架组织的影响，这些影响与细胞增殖和分化参数相关。用TGFβ（1.5 - 30 ng/mL）处理在无血清培养基中培养24小时的小鼠成骨细胞，可轻微（-23%）抑制碱性磷酸酶活性。同时，通过[³H] - 胸苷掺入DNA评估，TGFβ（0.5 - 30 ng/mL，24小时）可显著增加细胞复制（为对照的157%至325%）。在影响碱性磷酸酶和DNA合成的中位剂量（1.5 ng/mL）下（为对照的235%），TGFβ可诱导静止的小鼠成骨细胞快速（6小时）重新铺展。通过生化和免疫荧光方法评估，这种作用与肌动蛋白、α - 辅肌动蛋白和微管蛋白的聚合增加有关。此外，通过[³⁵S]甲硫氨酸标记和使用二维凝胶电泳对细胞骨架蛋白进行分级分离测定，TGFβ（1.5 ng/mL）可增加肌动蛋白、α - 辅肌动蛋白、波形蛋白和微管蛋白的从头生物合成。这些作用迅速且短暂，因为它们在6小时时出现，并在TGFβ暴露24小时后逆转。结果表明，TGFβ对骨内膜小鼠成骨细胞DNA合成的刺激作用与细胞铺展的短暂增加有关，这与细胞骨架蛋白的聚合和合成增强有关。
