WNT及TGF-β信号通路对鹿茸间充质干细胞软骨分化的影响

Cooperation between TGF-β and Wnt pathways during chondrocyte differentiation of velvet antler mesenchymal stem cells

目的 TGF-β和Wnt信号通路在控制某些发育事件和特定靶基因的活化中起主要作用。研究探究了二者是否在鹿茸间充质干细胞软骨分化过程中发生相互作用。方法利用TGF-β1诱导鹿茸间充质干细胞软骨分化,并在此过程中使用逆转录酶-聚合酶链式反应(RT-PCR)、蛋白质印迹和宏阵列分析Wnt信号相关基因和软骨细胞分化基因在鹿茸MSCs软骨分化中表达情况。结果TGF-β1刺激上调鹿茸间充质干细胞中共受体LRP5、兼并Wnt、Wnt2、Wnt4、Wnt5a、Wnt7a和Wnt10a基因表达。Western blot结果表明,TGF-β1能显著增加细胞中β-catenin蛋白表达。TGF-β在鹿茸间充质干细胞中上调Aggrecan基因表达。仅当TGF-β1和LiCl共同处理时,软骨细胞的COLⅡ基因才表达。结论 TGF-β刺激鹿茸间充质干细胞软骨细胞分化,同时激活TGF-β和Wnt信号通路,增加细胞中β-catenin蛋白表达,以及TGF-β和Wnt信号之间的协同作用,支持了Wnt信号传导是TGF-β刺激鹿茸间充质干细胞软骨形成的介质之一。

Objective TGF-β and Wnt signaling pathways play major roles in controling certain developmental events and activation of specific target genes. We tested whether these pathways interact during differentiation of chondrocytes and adipocytes in velvet antler mesenchymal stem cells. Methods Induction of chondrogenic differentiation of pilose antler mesenchymal stem cells by TGF-β1. Reverse transcriptase-polymerase chain reaction( RT-PCR),Western blot,and macroarrays were used for analysis of the modulation of TGF-β on Wnt signaling – associated genes,and chondrocyte differentiation genes in velvet antler mesenchymal stem cells. Results TGF-β1 activated genes in the TGF-β/Smad pathway,upregulated Wnt2,Wnt4,Wnt5 a,Wnt7 a,Wnt10 a,and Wnt co-receptor LRP5 in velvet antler mesenchymal stem cells. The results of Western blot showed that TGF-β1 could significantly increase the expression of β-catenin protein in cells. TGF-β1 significantly stimulated aggrecan gene expression. Velvet antler mesenchymal stem cells expressed collagen type II mRNA only when treated with both TGF-β1 and LiCl.Conclusion In summary,TGF-β stimulate velvet antler mesenchymal stem cells differentiation in vitro. The activation of both TGF-β and Wnt signal pathways by TGF-β,and synergy between TGF-β and Wnt signals,supports the viewthat Wnt-mediated signaling is one of the mechanisms of TGF-β’s effects on chondrocyte differentiation of velvet antler mesenchymal stem cells.