Eilam Y, Beit-Or A, Nevo Z
Biochem Biophys Res Commun. 1985 Oct 30;132(2):770-9. doi: 10.1016/0006-291x(85)91199-4.
Cartilage-derived growth factors, enhance proteoglycan synthesis in cultured chick-embryo chondrocytes, and have almost no effect on cell proliferation. Addition of cartilage derived growth factors to cartilage cells loaded with the fluorescent Ca2+ indicator quin 2, caused a rapid, concentration dependent decrease in cytoplasmic free Ca2+. This decrease persisted also in Ca2+-free medium, indicating that it is not mediated by a decrease in the passive permeability of cell membrane to Ca2+. Addition of the Ca2+ ionophore A23187, with or without cartilage derived factors, caused an increase in cytoplasmic free Ca2+ together with inhibition of proteoglycan synthesis and enhanced cell proliferation. The results may indicate that whereas cell proliferation in chondrocytes is signaled by an increase in cytoplasmic Ca2+ ([Ca2+]in), proteoglycan synthesis is signaled by a decrease in [Ca2+]in. The data lead to suggesting a mechanism for antagonistic regulation of cell proliferation and the expression of the differentiated state.
软骨衍生生长因子可增强培养的鸡胚软骨细胞中蛋白聚糖的合成，且对细胞增殖几乎没有影响。向负载有荧光钙指示剂喹啉-2的软骨细胞中添加软骨衍生生长因子，会导致细胞质游离钙迅速且呈浓度依赖性降低。这种降低在无钙培养基中也持续存在，表明它不是由细胞膜对钙的被动通透性降低所介导的。添加钙离子载体A23187，无论有无软骨衍生因子，都会导致细胞质游离钙增加，同时抑制蛋白聚糖合成并增强细胞增殖。结果可能表明，软骨细胞中的细胞增殖是由细胞质钙浓度升高（[Ca2+]in）发出信号，而蛋白聚糖合成则是由[Ca2+]in降低发出信号。这些数据提示了一种细胞增殖与分化状态表达的拮抗调节机制。
