Infection-induced up-regulation of the costimulatory molecule 4-1BB in osteoblastic cells and its inhibitory effect on M-CSF/RANKL-induced in vitro osteoclastogenesis
Infection-induced up-regulation of the costimulatory molecule 4-1BB in osteoblastic cells and its inhibitory effect on M-CSF/RANKL-induced in vitro osteoclastogenesis
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DOI：
10.1074/jbc.m303791200
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发表时间：
2004-04-02
影响因子：
4.8
通讯作者：
Nakayama, K
中科院分区：
文献类型：
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作者：
Saito, K;Ohara, N;Nakayama, K
细菌感染有时会损害骨代谢。在本研究中，我们用牛分枝杆菌卡介苗（BCG）感染成骨细胞系MC3T3-E1，并通过抑制消减杂交方法鉴定了BCG感染细胞中上调的基因。编码 4-1BB (CD137) 的基因（肿瘤坏死因子-α 受体家族的成员）被发现是上调的基因之一。大肠杆菌、鼠伤寒沙门氏菌和金黄色葡萄球菌感染以及脂多糖和热灭活卡介苗治疗也观察到 4-1BB 上调。发现骨髓细胞以及巨噬细胞样细胞系 J774 和 RAW264.7 表达 4-1BB 配体 (4-1BBL)。固定在培养板上的重组 4-1BB (r4-1BB) 强烈抑制巨噬细胞集落刺激因子 (M-CSF)/核因子 kappaB 配体受体激活剂 (RANKL) 诱导的体外骨髓细胞破骨细胞形成。抗4-1BBL抗体也在较小程度上抑制破骨细胞形成，表明在抑制破骨细胞形成过程中涉及通过4-1BBL的反向信号传导。酪蛋白激酶 I (CKI) 抑制剂显着抑制 r4-1BB 对 M-CSF/RANKL 诱导的破骨细胞形成的抑制作用，表明 CKI 可能参与 4-1BB/4-1BBL 反向信号传导。 r4-1BB 对 M-CSF 或 RANKL 诱导的 I-kappaB、ERK1/2、p38 或 JNK 磷酸化没有影响，而 RANKL 诱导的 Akt（磷脂酰肌醇 3-激酶 (PI3K) 下游靶标）磷酸化被 r4-1BB 完全消除，表明 4-1BB/4-1BBL 反向信号传导可能干扰 PI3K/Akt途径。 r4-1BB 还消除了 RANKL 介导的活化 T 细胞核因子 2 的诱导。这项研究可能阐明 4-1BB 在细胞代谢，特别是破骨细胞生成中的新作用。
Bacterial infection sometimes impairs bone metabolism. In this study, we infected the osteoblastic cell line MC3T3-E1 with Mycobacterium bovis bacillus Calmette-Guerin (BCG) and identified genes that were up-regulated in the BCG-infected cells by the suppression subtractive hybridization method. A gene encoding 4-1BB (CD137), a member of the tumor necrosis factor-alpha receptor family, was found to be one of the up-regulated genes. Up-regulation of 4-1BB was also observed by infection with Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus, and by treatment with lipopolysaccharides and heat-killed BCG. Bone marrow cells and the macrophage-like cell lines J774 and RAW264.7 were found to express 4-1BB ligand (4-1BBL). Recombinant 4-1BB (r4-1BB) that was immobilized on culture plates strongly inhibited macrophage colony stimulating factor (M-CSF)/receptor activator of nuclear factor-kappaB ligand (RANKL)-induced in vitro osteoclast formation from bone marrow cells. Anti-4-1BBL antibody also inhibited osteoclast formation to a lesser extent, indicating involvement of reverse signaling through 4-1BBL during inhibition of osteoclast formation. A casein kinase I (CKI) inhibitor markedly suppressed the inhibitory effect of r4-1BB on M-CSF/ RANKL-induced osteoclast formation, suggesting that CKI might be involved in 4-1BB/4-1BBL reverse signaling. r4-1BB showed no effects on M-CSF- or RANKL-induced phosphorylation of I-kappaB, ERK1/2, p38, or JNK, whereas RANKL-induced phosphorylation of Akt, a downstream target of phosphatidylinositol 3-kinase (PI3K), was completely abolished by r4-1BB, suggesting that 4-1BB/4-1BBL reverse signaling may interfere with PI3K/Akt pathway. r4-1BB also abolished RANKL-mediated induction of nuclear factor of activated T cells-2. This study may elucidate a novel role of 4-1BB in cell metabolism, especially osteoclastogenesis.