Cooperative Regulation of Chondrocyte Differentiation by CCN2 and CCN3 Shown by a Comprehensive Analysis of the CCN Family Proteins in Cartilage
Cooperative Regulation of Chondrocyte Differentiation by CCN2 and CCN3 Shown by a Comprehensive Analysis of the CCN Family Proteins in Cartilage
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DOI：
10.1359/jbmr.080615
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发表时间：
2008-11-01
影响因子：
6.2
通讯作者：
Takigawa, Masaharu
中科院分区：
文献类型：
--
作者：
Kawaki, Harumi;Kubota, Satoshi;Takigawa, Masaharu
CCN 2是CCN家族成员中软骨细胞分化的促进剂。其无效小鼠显示骨骼畸形。然而，很少有人知道其他CCN成员在软骨细胞中的作用。使用体内和体外方法，我们对CCN 2缺失和野生型小鼠进行了比较分析，以研究CCN 2和其他CCN蛋白在软骨发育中的作用。免疫组织化学用于评估CCN蛋白和其他软骨细胞相关分子在两种类型小鼠中的定位。此外，基因表达水平和外源性CCN蛋白油软骨细胞增殖，分化和软骨细胞相关基因在其原代软骨细胞中的表达的影响进行了评估。CCN 3在CCN 2缺失的软骨和软骨细胞中显著上调。这种上调与细胞增殖减少和分化延迟有关。与体内研究结果一致，CCN 2缺失完全延缓了软骨细胞终末分化，并降低了体外几种软骨细胞相关基因的表达。而CcO表达显著增加。相反，外源CCN 2的加入强烈地促进分化并诱导相关基因的表达。而CcO表达则降低。这些发现共同表明，CCN 2通过调节软骨细胞相关基因的表达诱导软骨细胞分化，但这些作用被CCN 3抵消。CCN 2的缺乏导致CCN 2缺失小鼠中CCN 3的上调，这导致观察到的表型，例如最终分化的延迟。PTHrP-Ihh环参与CCN 3表达的调节。
CCN2 is best known as a promoter of chondrocyte differentiation among the CCN family members. and its null mice display skeletal dysmorphisms. However, little is known concerning roles of the other CCN members in chondrocytes. Using both in vivo and in vitro approaches, We conducted a comparative analysis of CCN2-null and wildtype mice to study the roles of CCN2 and the other CCN proteins in cartilage development. Immunohistochemistry was used to evaluate the localization of CCN proteins and other chondrocyte-associated molecules in the two types of mice. Moreover, gene expression levels and the effects of exogenous CCN proteins oil chondrocyte proliferation, differentiation, and the expression of chondrocyte-associated genes in their primary chondrocytes were evaluated. Ccn3 was dramatically upregulated in CCN2-null cartilage and chondrocytes. This upregulation was associated with diminished cell proliferation and delayed differentiation. Consistent with the in vivo findings, CCN2 deletion entirely retarded chondrocyte terminal differentiation and decreased the expression of several chondrocyte-associated genes ill vitro. whereas CcO expression drastically increased. In contrast, the addition Of exogenous CCN2 promoted differentiation strongly and induced the expression of the associated genes. whereas decreasing, the CcO expression. These findings collectively indicate that CCN2 induces chondrocyte differentiation by regulating the expression of chondrocyte-associated genes but that these effects are counteracted by CCN3. The lack of CCN2 caused upregulation of CCN3 in CCN2-null mice, which resulted in the observed phenotypes, Such as the resultant delay of terminal differentiation. The involvement of the PTHrP-Ihh loop in the regulation of CCN3 expression is also suggested.