The calcineurin/nuclear factor of activated T cells signaling pathway regulates osteoclastogenesis in RAW264.7 cells
The calcineurin/nuclear factor of activated T cells signaling pathway regulates osteoclastogenesis in RAW264.7 cells
复制标题
DOI：
10.1074/jbc.m213067200
复制
发表时间：
2004-04-02
影响因子：
4.8
通讯作者：
Clipstone, NA
中科院分区：
文献类型：
--
作者：
Hirotani, H;Tuohy, NA;Clipstone, NA
尽管钙调神经磷酸酶/活化T细胞核因子(NFAT)信号通路在T淋巴细胞活化中的作用已为人所知，但它也参与了多种不同细胞类型的广泛的其他生物学反应。在此，我们研究了钙调神经磷酸酶/NFAT信号通路在破骨细胞分化调控中的作用。破骨细胞是在核因子-kappaB受体激活剂(RANKL)的刺激下，从单核/巨噬细胞系分化而来的具有骨吸收功能的多核细胞。我们现在报道，用免疫抑制剂环孢素A和FK506抑制钙调神经磷酸酶，或者逆转录病毒介导的特定钙调神经磷酸酶抑制肽的异位表达，都能有效地抑制RANKL诱导的RAW264.7单核/巨噬细胞系向成熟的多核破骨细胞的分化。此外，我们还发现NFAT家族成员在RAW264.7细胞中表达，并且其表达受RANKL刺激而上调。最重要的是，我们发现在RAW264.7细胞中异位表达具有结构性活性、不依赖钙调神经磷酸酶的NFATc1突变体足以诱导这些细胞表达破骨细胞特有的基因表达模式，并分化为形态不同的多核破骨细胞，能够诱导生理矿化基质的吸收。综上所述，这些数据将钙调神经磷酸酶定义为RANKL诱导的信号转导通路的重要下游效应因子，导致破骨细胞分化的诱导，并进一步表明，NFATc1转录因子的激活足以启动导致成熟功能破骨细胞表型规范的遗传程序。
Although best known for its role in T lymphocyte activation, the calcineurin/nuclear factor of activated T cells ( NFAT) signaling pathway is also known to be involved in a wide range of other biological responses in a variety of different cell types. Here we have investigated the role of the calcineurin/NFAT signaling pathway in the regulation of osteoclast differentiation. Osteoclasts are bone-resorbing multinucleated cells that are derived from the monocyte/macrophage cell lineage after stimulation with a member of the tumor necrosis factor family of ligands known as receptor activator of nuclear factor-kappaB ligand (RANKL). We now report that inhibition of calcineurin with either the immunosuppressant drugs cyclosporin A and FK506, or the retrovirally mediated ectopic expression of a specific calcineurin inhibitory peptide, all potently inhibit the RANKL-induced differentiation of the RAW264.7 monocyte/macrophage cell line into mature multinucleated osteoclasts. In addition, we find that NFAT family members are expressed in RAW264.7 cells and that their expression is up-regulated in response to RANKL stimulation. Most importantly, we find that ectopic expression of a constitutively active, calcineurin-independent NFATc1 mutant in RAW264.7 cells is sufficient to induce these cells to express an osteoclast-specific pattern of gene expression and differentiate into morphologically distinct, multinucleated osteoclasts capable of inducing the resorption of a physiological mineralized matrix substrate. Taken together, these data define calcineurin as an essential downstream effector of the RANKL-induced signal transduction pathway leading toward the induction of osteoclast differentiation and furthermore, indicate that the activation of the NFATc1 transcription factor is sufficient to initiate a genetic program that results in the specification of the mature functional osteoclast cell phenotype.