Kaji H, Sugimoto T, Kanatani M, Fukase M, Chihara K
Department of Medicine, Kobe University School of Medicine, Japan.
Biochem Biophys Res Commun. 1993 Jul 15;194(1):157-62. doi: 10.1006/bbrc.1993.1798.
The present study was performed to examine whether parathyroid hormone (PTH) and parathyroid hormone-related peptide (PTHrP) would stimulate osteoclast-like cell formation via soluble factor(s) released from osteoblasts and, if so, to characterize the involvement of PTH/PTHrP-responsive dual signal transduction systems [cAMP-dependent protein kinase (PKA) and calcium/protein kinase C(PKC)]. Osteoblasts-conditioned medium (CM) was obtained from rat osteoblastic osteosarcoma cells (UMR-106 cells), which had been cultured in serum free medium for 24 hrs after treatment with various kinds of reagents. The CM of osteoblasts treated with either 10(-7) M human(h) PTH-(1-34) or 10(-7)M hPTHrP-(1-34) equally stimulated osteoclast-like cell formation from hemopoietic blast cells derived from mouse spleen cells, although the CM treated with 10(-8) M 1,25dihydroxyvitamin D3 failed to affect it. The CM treated with both 10(-4) M dibutyryl-cAMP and a direct PKA activator, 10(-4)M Sp-cAMPS significantly increased osteoclast-like cell formation. The CM treated with a PKC activator, 10(-7)M phorbol 12-myristate 13-acetate (PMA) and calcium ionophores (10(-7)M A23187 and 10(-7)M ionomycin) also significantly enhanced osteoclast-like cell formation. The present study first indicated that osteoblast-mediated stimulation of osteoclast-like cell formation by PTH and PTHrP, and the participation of PTH/PTHrP-responsive dual signal transduction systems of osteoblasts in the stimulation of osteoclast-like cell formation by PTH and PTHrP.
本研究旨在探讨甲状旁腺激素（PTH）和甲状旁腺激素相关肽（PTHrP）是否会通过成骨细胞释放的可溶性因子刺激破骨细胞样细胞形成，如果是，则表征PTH/PTHrP反应性双信号转导系统[环磷酸腺苷依赖性蛋白激酶（PKA）和钙/蛋白激酶C（PKC）]的参与情况。成骨细胞条件培养基（CM）取自大鼠成骨细胞骨肉瘤细胞（UMR-106细胞），这些细胞在用各种试剂处理后在无血清培养基中培养24小时。用10^(-7)M人（h）PTH-(1-34)或10^(-7)M hPTHrP-(1-34)处理的成骨细胞CM同样刺激了源自小鼠脾细胞的造血母细胞形成破骨细胞样细胞，而用10^(-8)M 1,25-二羟基维生素D3处理的CM未能影响其形成。用10^(-4)M二丁酰环磷酸腺苷和直接的PKA激活剂10^(-4)M Sp-cAMPS处理的CM显著增加了破骨细胞样细胞的形成。用PKC激活剂10^(-7)M佛波醇12-肉豆蔻酸酯13-乙酸酯（PMA）和钙离子载体（10^(-7)M A23187和10^(-7)M离子霉素）处理的CM也显著增强了破骨细胞样细胞的形成。本研究首次表明，成骨细胞介导的PTH和PTHrP对破骨细胞样细胞形成的刺激作用，以及成骨细胞的PTH/PTHrP反应性双信号转导系统参与PTH和PTHrP对破骨细胞样细胞形成的刺激作用。
