Effects of Overexpression of Membrane-bound Transferrin-like Protein (MTf) on Chondrogenic Differentiation in Vitro*
Effects of Overexpression of Membrane-bound Transferrin-like Protein (MTf) on Chondrogenic Differentiation in Vitro*
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膜结合转铁蛋白样蛋白 (MTf) 过表达对体外软骨分化的影响*
DOI：
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发表时间：
2002
影响因子：
4.8
通讯作者：
Y. Kato
中科院分区：
文献类型：
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作者：
Ketut Suardita;K. Fujimoto;R. Oda;A. Shimazu;K. Miyazaki;T. Kawamoto;Y. Kato
膜结合转铁蛋白样蛋白（MTf）在软骨细胞分化过程中与软骨特征基因的表达同时表达，且软骨中的MTf水平远高于其他组织。为了研究 MTf 在软骨中的作用，我们检测了生长因子对小鼠软骨形成前 ATDC5 细胞中 MTf 表达的影响，以及 MTf 过表达对 ATDC5 和小鼠多能间充质 C3H10T1/2 细胞分化的影响。在 ATDC5 培养物中，当骨形态发生蛋白 2 和转化生长因子 β 以及胰岛素诱导软骨分化时，这些肽会诱导 MTf mRNA 表达。在 ATDC5 细胞中强制表达兔 MTf 会诱导聚集蛋白聚糖、II 型胶原、matrilin-1、X 型胶原 mRNA，以及从成纤维细胞到球形软骨细胞的细胞形状变化。因此，MTf表达培养物中蛋白多糖的合成和积累高于对照培养物。 MTf 过表达的这些影响与细胞表面的 MTf 蛋白水平相关，并且在抗 MTf 抗体存在时减弱。然而，过表达MTf的ATDC5细胞中聚集蛋白聚糖mRNA水平低于暴露于10μg/ml胰岛素的野生型ATDC5细胞。 C3H10T1/2 细胞中 MTf 过表达也诱导聚集蛋白聚糖和/或 II 型胶原 mRNA，但不诱导球形表型。这些发现表明，细胞表面的 MTf 表达促进了软骨形成前细胞的分化，尽管单独 MTf 过表达似乎不足以使多能间充质细胞分化为软骨细胞谱系。
Membrane-bound transferrin-like protein (MTf) is expressed in parallel with the expression of cartilage-characteristic genes during differentiation of chondrocytes, and the MTf level is much higher in cartilage than in other tissues. To investigate the role of MTf in cartilage, we examined the effects of growth factors on MTf expression in mouse prechondrogenic ATDC5 cells and the effect of MTf overexpression on differentiation of ATDC5 and mouse pluripotent mesenchymal C3H10T1/2 cells. In ATDC5 cultures, bone morphogenetic protein-2 and transforming growth factor-β as well as insulin induced MTf mRNA expression when these peptides induced chondrogenic differentiation. Forced expression of rabbit MTf in ATDC5 cells induced aggrecan, type II collagen, matrilin-1, type X collagen mRNAs, and cell-shape changes from fibroblastic cells to spherical chondrocytes. Accordingly, the synthesis and accumulation of proteoglycans were higher in MTf-expressing cultures than in control cultures. These effects of MTf overexpression correlated with the MTf protein level on the cell surface and decreased in the presence of anti-MTf antibody. However, the aggrecan mRNA level in the ATDC5 cells overexpressing MTf was lower than that in wild type ATDC5 cells exposed to 10 μg/ml insulin. MTf overexpression in C3H10T1/2 cells also induced aggrecan and/or type II collagen mRNA but not the spherical phenotype. These findings suggest that the expression of MTf on the cell surface facilitates the differentiation of prechondrogenic cells, although MTf overexpression alone seems to be insufficient to commit pluripotent mesenchymal cells to the chondrocyte lineage.