Leptin regulates chondrocyte differentiation and matrix maturation during endochondral ossification
Leptin regulates chondrocyte differentiation and matrix maturation during endochondral ossification
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DOI：
10.1016/j.bone.2005.05.009
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发表时间：
2005-11-01
期刊：
影响因子：
4.1
通讯作者：
Myoui, A
中科院分区：
文献类型：
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作者：
Kishida, Y;Hirao, M;Myoui, A
瘦素通过其广泛表达的受体（Ob-Rb）介导多种作用，包括骨发育。在这项研究中，我们研究了瘦素在生长板软骨内骨化中的作用。分析野生型和ob/ob小鼠的生长板。采用软骨细胞原代培养和ATDC 5细胞分化培养系统观察瘦素对软骨细胞基因表达、细胞周期、细胞凋亡和基质矿化的影响。免疫组化和原位杂交结果显示，瘦素定位于正常小鼠肥大前软骨细胞，而Ob-Rb定位于正常和ob/ob小鼠肥大软骨细胞。在机械测试中，ob/ob小鼠的生长板比野生型小鼠的生长板更脆弱，并且在软骨-骨连接处容易破裂。ob/ob小鼠生长板柱状结构紊乱，X型胶原表达减少，胶原纤维排列紊乱，细胞凋亡增加，过早矿化。肥胖基因型小鼠给予瘦素后，股骨和肱骨长度增加，钙化肥大区与整个肥大区的比例长度减少。在原代软骨细胞培养中，ob/ob软骨细胞中的基质矿化比野生型小鼠强;通过加入外源性瘦素（10 ng/ml），这两种类型小鼠中的矿化被废除。在ATDC 5细胞分化培养过程中，外源性瘦素在1 - 10 ng/ml（相当于正常血清瘦素浓度）的浓度下改变了X型胶原mRNA的表达，抑制了细胞凋亡、细胞生长和基质钙化。总之，我们证明了瘦素调节与软骨细胞终末分化相关的几个事件。我们发现ob/ob小鼠的生长板是脆弱的，这意味着生长板的分化/成熟过程中的干扰，由于在ob/ob小鼠瘦素信号的耗尽。这些结果表明，外周瘦素信号在生长板的软骨内骨化中起着重要作用。(c)2005年爱思唯尔公司All rights reserved.
Leptin has been suggested to mediate a variety of actions, including bone development, via its ubiquitously expressed receptor (Ob-Rb). In this study, we investigated the role of leptin in endochondral ossification at the growth plate. The growth plates of wild-type and ob/ob mice were analyzed. Effects of leptin on chondrocyte gene expression, cell cycle, apoptosis and matrix mineralization were assessed using primary chondrocyte Culture and the ATDC5 cell differentiation culture system. Immunohistochemistry and in situ hybridization showed that leptin was localized in prehypertrophic chondrocytes in normal mice and that Ob-Rb was localized in hypertrophic chondrocytes in normal and ob/ob mice. Growth plates of ob/ob mice were more fragile than those of wild-type mice in a mechanical test and were broken easily at the chondro-osseous junction. The growth plates of ob/ob mice showed disturbed columnar structure, decreased type X collagen expression, less organized collagen fibril arrangement, increased apoptosis and premature mineralization. Leptin administration in ob/ob mice led to an increase in femoral and humeral lengths and decrease in the proportional length of the calcified hypertrophic zone to the whole hypertrophic zone. In primary chondrocyte culture, the matrix mineralization in ob/ob chondrocytes was stronger than that of wild-type mice; this mineralization in both types of mice was abolished by the addition of exogenous leptin (10 ng/ml). During ATDC5 cell differentiation Culture, exogenous leptin at a concentration of 1 - 10 ng/ml (equivalent to the normal serum concentration of leptin) altered type X collagen mRNA expression and Suppressed apoptosis, cell growth and matrix calcification. In conclusion, we demonstrated that leptin modulates several events associated with terminal differentiation of chondrocytes. Our finding that the growth plates of ob/ob mice were fragile implies a disturbance in the differentiation/maturation process of growth plates due to depletion of leptin signaling in ob/ob mice. These findings suggest that peripheral leptin signaling plays in essential role in endochondral ossification at the growth plate. (c) 2005 Elsevier Inc. All rights reserved.