Nasatzky E, Azran E, Dean D D, Boyan B D, Schwartz Z
Department of Periodontics, Hebrew University Hadassah Faculty of Dental Medicine, Jerusalem, Israel.
Endocrine. 2000 Dec;13(3):305-13. doi: 10.1385/ENDO:13:3:305.
Parathyroid hormone (1-34) (PTH(1-34) and transforming growth factor-beta1 (TGF-beta1) regulate chondrocyte proliferation, differentiation, and matrix synthesis. Both proteins mediate their effects in a dose- and time-dependent manner, and the effects are cell maturation specific. Moreover, similar signaling pathways are used, suggesting that there may be cross talk leading to coregulated cell response. To test this hypothesis, confluent cultures of rat costochondral resting zone and growth zone chondrocytes were treated with 0.22, 0.44, or 0.88 ng/mL of rhTGF-beta1 for 24 h, followed by treatment with 10(-11) to 10(-8) M PTH(1-34) for 10 min or 24 h. [3H]-Thymidine incorporation, specific activity of alkaline phosphatase (AP), and [35S]-sulfate incorporation were measured. PTH(1-34) had no effect on [3H]-thymidine incorporation by growth zone cells pretreated with 0.22 or 0.44 ng/mL of TGF-beta1, but in cultures treated with 0.88 ng/mL, PTH(1-34) caused a dose-dependent decrease that was maximal at the lowest concentration tested. By contrast, PTH(1-34) stimulated [3H]-thymidine incorporation by resting zone cells, and this effect was additive with the stimulation caused by 0.22 ng/mL of TGF-beta1. PTH(1-34) caused a synergistic increase in AP in growth zone cells treated with 0.44 or 0.88 ng/mL of TGF-beta1, but not in cells treated with 0.22 ng/mL of TGF-beta1. It had no effect on AP in resting zone cells pretreated with any concentration of TGF-beta1. PTH(1-34) increased [35S]-sulfate incorporation in growth zone and resting zone cell cultures treated with 0.22 ng/mL of TGF-beta1 to levels seen in cultures treated with 0.88 ng/mL of TGF-beta1 alone. These results support the hypothesis that PTH(1-34) and TGF-beta1 coregulate growth plate chondrocytes and that the effects are cell maturation dependent.
甲状旁腺激素（1-34）（PTH(1-34)）和转化生长因子-β1（TGF-β1）调节软骨细胞的增殖、分化和基质合成。这两种蛋白质均以剂量和时间依赖性方式介导其作用，且这些作用具有细胞成熟特异性。此外，它们使用相似的信号通路，这表明可能存在相互作用从而导致共同调节的细胞反应。为了验证这一假设，将大鼠肋软骨静止区和生长区软骨细胞的汇合培养物用0.22、0.44或0.88 ng/mL的重组人转化生长因子-β1（rhTGF-β1）处理24小时，随后用10⁻¹¹至10⁻⁸ M的PTH(1-34)处理10分钟或24小时。测量了[³H] - 胸腺嘧啶核苷掺入、碱性磷酸酶（AP）的比活性以及[³⁵S] - 硫酸盐掺入情况。PTH(1-34)对用0.22或0.44 ng/mL的TGF-β1预处理的生长区细胞的[³H] - 胸腺嘧啶核苷掺入没有影响，但在用0.88 ng/mL处理的培养物中，PTH(1-34)导致剂量依赖性降低，在测试的最低浓度下达到最大降幅。相比之下，PTH(1-34)刺激静止区细胞的[³H] - 胸腺嘧啶核苷掺入，并且这种作用与0.22 ng/mL的TGF-β1所引起的刺激相加。PTH(1-34)在用0.44或0.88 ng/mL的TGF-β1处理的生长区细胞中导致AP协同增加，但在用0.22 ng/mL的TGF-β1处理的细胞中没有这种作用。它对用任何浓度的TGF-β1预处理的静止区细胞中的AP没有影响。PTH(1-34)在用0.22 ng/mL的TGF-β1处理的生长区和静止区细胞培养物中使[³⁵S] - 硫酸盐掺入增加到仅用0.88 ng/mL的TGF-β1处理的培养物中所观察到的水平。这些结果支持以下假设：PTH(1-34)和TGF-β1共同调节生长板软骨细胞，且这些作用取决于细胞成熟度。
