Protein Kinase D Promotes in Vitro Osteoclast Differentiation and Fusion
Protein Kinase D Promotes in Vitro Osteoclast Differentiation and Fusion
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DOI：
10.1074/jbc.m112.444133
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发表时间：
2013-04-05
影响因子：
4.8
通讯作者：
Gopalakrishnan, Rajaram
中科院分区：
文献类型：
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作者：
Mansky, Kim C.;Jensen, Eric D.;Gopalakrishnan, Rajaram
尽管 PKD 广泛表达并参与许多细胞过程，但其在破骨细胞中的功能此前尚未报道。在这项研究中，我们发现 PKD2 是破骨细胞中表达的主要 PKD 亚型。用 M-CSF 和 RANKL 处理骨髓巨噬细胞 2-3 天后，表明激活状态的 PKD 磷酸化增加，对应于破骨细胞前融合的开始。针对 PKD2 的 RNAi 和 PKD 抑制剂 CID755673 的治疗表明，PKD 活性对于诱导骨髓巨噬细胞转化为培养物中的酒石酸抗性酸性磷酸酶阳性前破骨细胞来说是可有可无的，但对于从单核前破骨细胞向多核破骨细胞的转变是必需的。 PKD 活性的丧失降低了 RANKL 刺激的培养物中 DC-STAMP 的表达。 DC-STAMP 的过表达足以挽救 CID755673 的治疗并恢复与多核破骨细胞的融合。从这些数据中，我们得出结论，PKD 活性通过增加 DC-STAMP 的表达来促进破骨细胞祖细胞的分化。
Although PKD is broadly expressed and involved in numerous cellular processes, its function in osteoclasts has not been previously reported. In this study, we found that PKD2 is the main PKD isoform expressed in osteoclastic cells. PKD phosphorylation, indicative of the activated state, increased after 2-3 days of treatment of bone marrow macrophages with M-CSF and RANKL, corresponding to the onset of preosteoclast fusion. RNAi against PKD2 and treatment with the PKD inhibitor CID755673 showed that PKD activity is dispensable for induction of bone marrow macrophages into tartrate-resistant acid phosphatase-positive preosteoclasts in culture but is required for the transition from mononucleated preosteoclasts to multinucleated osteoclasts. Loss of PKD activity reduced expression of DC-STAMP in RANKL-stimulated cultures. Overexpression of DC-STAMP was sufficient to rescue treatment with CID755673 and restore fusion into multinucleated osteoclasts. From these data, we conclude that PKD activity promotes differentiation of osteoclast progenitors through increased expression of DC-STAMP.