基因沉默组织型转谷氨酰胺酶抑制SaOS-2细胞成骨分化

目的 研究组织型转谷氨酰胺酶（tissue transglutaminase, TG2）是否参与人SaOS-2细胞系成骨分化过程。方法 使用携带短发夹RNA（short hairpin RNA, shRNA）的慢病毒转染SaOS-2细胞以敲减TG2表达，以SaOS-2细胞及转染了含阴性对照shRNA病毒的SaOS-2作为对照组，分别进行体外成骨诱导培养，并进行以下检测：1）诱导14 d后各组矿化情况（茜素红染色），2）诱导4 d、7 d后碱性磷酸酶活性及I型胶原、骨钙素、骨形态发生蛋白-2（BMP-2）的mRNA表达，并与诱导前的表达水平相比较。结果 SaOS-2细胞组及转染阴性对照shRNA组在体外成骨诱导过程中I型胶原、骨钙素、BMP-2的mRNA表达和ALP活性逐渐增加，14 d时形成明显矿化结节，而TG2敲减后的SaOS-2细胞在诱导14 d时矿化水平显著低于对照组，诱导7 d时ALP活性及I型胶原、骨钙素、BMP-2的mRNA表达水平显著低于对照组。结论 组织型转谷氨酰胺酶参与SaOS-2细胞体外成骨分化及矿化。

Knockdown of tissue transglutaminase in SaOS-2 cell line inhibits its osteoblastic differentiation and mineralization

Objective To investigate the issue that whether TG2 plays an important role in the osteoblast differentiation and mineralization. Methods TG2 mRNA of SaOS-2 was knocked down through stable expression of a short-hairpin(sh) RNA targeting TG2 and then the cells were cultured in osteo-inductive medium for 14 d to measure mineralization and 7 d to measure the level of osteoblastic differentiation markers including ALP activity and mRNA of collagen I, osteocalcin(OCN) and BMP-2, wild-type SaOS-2 cells and scrambled shRNA-transducted SaOS-2 cells served as the controls. Results The controls displayed an increasing trend on the level of ALP activity and mRNA of collagen I, osteocalcin and BMP-2, and notable mineralization at 14 d. When TG2 was knocked down, ALP activity, mRNA of collagen I, osteocalcin and BMP-2 at 7 d, and mineralization at 14 d were all at lower level in comparison with the corresponding values in the controls. Conclusion TG2 plays a key role in the differentiation and mineralization of osteoblast.