Rankl-induced osteoclastogenesis leads to loss of mineralization in a medaka osteoporosis model
Rankl-induced osteoclastogenesis leads to loss of mineralization in a medaka osteoporosis model
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DOI：
10.1242/dev.071035
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发表时间：
2012-01-01
期刊：
影响因子：
4.6
通讯作者：
Winkler, Christoph
中科院分区：
文献类型：
--
作者：
Thuy Thanh To;Witten, P. Eckhard;Winkler, Christoph
破骨细胞是与巨噬细胞相关的造血来源的骨吸收细胞。破骨细胞生成的调控因子对于研究骨质疏松症等骨疾病的病理和治疗具有重要意义。在哺乳动物中，NF-κ B配体的受体活化剂（Rankl）是破骨细胞形成和活化的调节剂：其错误表达引起破骨细胞刺激和骨质疏松性骨丢失。在这里，我们报告了一种由青鳉模型中Rankl过表达诱导的突变表型。我们产生了转基因青鳉品系，其在受精后12天（dpf）开始在破骨细胞中的组织蛋白酶K启动子的控制下表达GFP，或在双向热休克启动子的控制下表达Rankl和CFP。使用双和三转基因幼虫的长期共聚焦延时成像，我们监测体内破骨细胞的形成和激活，以及它们与成骨细胞的相互作用。在Rankl诱导后，GFP阳性破骨细胞首先在椎间区域中观察到，然后迅速迁移到矿化的神经和血管弓的表面，以及椎体的中心。这些破骨细胞是TRAP（抗酒石酸酸性磷酸酶）和组织蛋白酶K阳性的、单核的和具有动态延伸的突起的高度移动的。它们仅与矿化基质紧密接触。Rankl诱导的破骨细胞形成导致椎体和椎弓中矿化基质严重降解。总之，我们的体内成像方法证实了Rankl在硬骨鱼中破骨细胞生成中的保守作用，并为动物模型中骨吸收过程中的细胞相互作用提供了新的见解，该模型可用于遗传和化学筛选。
Osteoclasts are macrophage-related bone resorbing cells of hematopoietic origin. Factors that regulate osteoclastogenesis are of great interest for investigating the pathology and treatment of bone diseases such as osteoporosis. In mammals, receptor activator of NF-kappa B ligand (Rankl) is a regulator of osteoclast formation and activation: its misexpression causes osteoclast stimulation and osteoporotic bone loss. Here, we report an osteoporotic phenotype that is induced by overexpression of Rankl in the medaka model. We generated transgenic medaka lines that express GFP under control of the cathepsin K promoter in osteoclasts starting at 12 days post-fertilization (dpf), or Rankl together with CFP under control of a bi-directional heat-shock promoter. Using long-term confocal time-lapse imaging of double and triple transgenic larvae, we monitored in vivo formation and activation of osteoclasts, as well as their interaction with osteoblasts. Upon Rankl induction, GFP-positive osteoclasts are first observed in the intervertebral regions and then quickly migrate to the surface of mineralized neural and haemal arches, as well as to the centra of the vertebral bodies. These osteoclasts are TRAP (tartrate-resistant acid phosphatase) and cathepsin K positive, mononuclear and highly mobile with dynamically extending protrusions. They are exclusively found in tight contact with mineralized matrix. Rankl-induced osteoclast formation resulted in severe degradation of the mineralized matrix in vertebral bodies and arches. In conclusion, our in vivo imaging approach confirms a conserved role of Rankl in osteoclastogenesis in teleost fish and provides new insight into the cellular interactions during bone resorption in an animal model that is useful for genetic and chemical screening.