Kawaida Reimi, Ohtsuka Toshiaki, Okutsu Junichi, Takahashi Tohru, Kadono Yuho, Oda Hiromi, Hikita Atsuhiko, Nakamura Kozo, Tanaka Sakae, Furukawa Hidehiko
Biomedical Research Laboratories, Sankyo Co., Ltd., Shinagawa-ku, Tokyo 140-8710, Japan.
J Exp Med. 2003 Apr 21;197(8):1029-35. doi: 10.1084/jem.20021321.
Osteoclasts are multinucleated cells that resorb bones, and are derived from hematopoietic cells of the monocyte/macrophage lineage. The receptor activator of NF-kappaB ligand (RANKL, also called ODF/TRANCE/OPGL) stimulates both osteoclast differentiation from osteoclast progenitors and activation of mature osteoclasts. To identify genes responsible for osteoclast differentiation, we used a molecular indexing technique. Here, we report a clone of one of these genes whose transcription is induced by soluble RANKL (sRANKL) in both the RAW264.7 cells of the mouse macrophage cell line and the mouse primary bone marrow cells. The predicted protein was found to be a mouse homologue of Jun dimerization protein 2 (JDP2), a member of the AP-1 family of transcription factors, containing a basic region-leucine zipper motif. Transient transfection experiments revealed that overexpression of JDP2 leads to activation of both tartrate-resistant acid phosphatase (TRAP) and cathepsin K gene promoters in RAW264.7 cells. Infection of mouse primary bone marrow cells with retroviruses expressing JDP2-facilitated sRANKL-mediated formation of TRAP-positive multinuclear osteoclasts. Importantly, antisense oligonucleotide to JDP2 strongly suppressed sRANKL-induced osteoclast formation of RAW264.7 cells. Our findings suggest that JDP2 may play an important role in the RANK-mediated signal transduction system, especially in osteoclast differentiation.
破骨细胞是多核细胞，可重吸收骨骼，由单核细胞/巨噬细胞谱系的造血细胞衍生而来。核因子κB受体活化因子配体（RANKL，也称为ODF/TRANCE/OPGL）既刺激破骨细胞前体向破骨细胞的分化，也刺激成熟破骨细胞的活化。为了鉴定负责破骨细胞分化的基因，我们使用了一种分子索引技术。在此，我们报告了其中一个基因的克隆，其转录在小鼠巨噬细胞系RAW264.7细胞和小鼠原代骨髓细胞中均由可溶性RANKL（sRANKL）诱导。预测的蛋白质被发现是Jun二聚化蛋白2（JDP2）的小鼠同源物，JDP2是转录因子AP-1家族的成员，含有一个碱性区域-亮氨酸拉链基序。瞬时转染实验表明，JDP2的过表达导致RAW264.7细胞中抗酒石酸酸性磷酸酶（TRAP）和组织蛋白酶K基因启动子的激活。用表达JDP2的逆转录病毒感染小鼠原代骨髓细胞促进了sRANKL介导的TRAP阳性多核破骨细胞的形成。重要的是，针对JDP2的反义寡核苷酸强烈抑制了RAW264.7细胞中sRANKL诱导的破骨细胞形成。我们的研究结果表明，JDP2可能在RANK介导的信号转导系统中发挥重要作用，尤其是在破骨细胞分化过程中。
