Li Jun, Zhang Yongqing, Zhao Qingxia, Wang Jianghua, He Xijing
Cell Physiol Biochem. 2015;37(6):2194-208. doi: 10.1159/000438576. Epub 2015 Nov 27.
BACKGROUND/AIMS: Elucidation of the molecular mechanisms governing osteoblast differentiation and angiogenesis are of great importance for improving the treatment of bone-related diseases. In this study, we examined the role of microRNA (miR)-10a in the differentiation of MC3T3-E1 cells and pro angiogenic activity of mouse umbilical vein endothelial cells (MUVECs).
The murine pre-osteoblast cell line MC3T3-E1 and MUVECs were used in the experiment. After transfected with miR-10a mimics or inhibitors, with or without LiCl pretreatment, the miR-10a, ALP, Runx2, Osx, OC and Dlx5 expression were assessed by RT-PCR. MC3T3-E1 cells were cultured with BMP2 to differentiate into bone cells, osteogenic differentiation of MC3T3-E1 cells were detected by ALP and ARS staining. Cell viability were analyzed by MTT and the protein expression of β-catenin, LEF1, cyclinD1, MMP2, and VEGF were detected by Western blotting; VEGF and VE-cadherin release were assessed by ELISA, and the migration of MUVECs, as well as tube formation were also detected.
MiR-10a expression was obviously down-regulated during osteogenic differentiation. Overexpression of miR-10a inhibited osteogenic differentiation of MC3T3-E1 cells, effectively decreasing MUVECs proliferation, migration, VEGF expression, VE-cadherin concentrations, and tube formation in vitro, whereas miR-10a silence enhanced those processes. Further mechanism assays demonstrated that overexpression of miR-10a reduced the β-catenin at both protein and transcription level, while pretreatment with Wnt signaling activator Licl partially attenuated the suppression effects of miR-10a overexpression on osteoblast differentiation and angiogenesis.
Our findings imply that miR-10a plays a suppressive role in osteoblast differentiation of MC3T3-E1 cells and pro angiogenic activity of MUVECs by regulating the β-catenin expression, representing a novel and potential therapeutic target for the treatment of bone regeneration-related diseases.
背景/目的:阐明调控成骨细胞分化和血管生成的分子机制对于改善骨相关疾病的治疗具有重要意义。在本研究中,我们检测了微小RNA(miR)-10a在MC3T3-E1细胞分化及小鼠脐静脉内皮细胞(MUVECs)促血管生成活性中的作用。
实验采用小鼠前成骨细胞系MC3T3-E1和MUVECs。用miR-10a模拟物或抑制剂转染细胞,有无LiCl预处理,通过RT-PCR评估miR-10a、碱性磷酸酶(ALP)、Runx2、Osx、骨钙素(OC)和Dlx5的表达。用骨形态发生蛋白2(BMP2)培养MC3T3-E1细胞使其分化为骨细胞,通过ALP和茜素红染色检测MC3T3-E1细胞的成骨分化。通过MTT分析细胞活力,用蛋白质印迹法检测β-连环蛋白、淋巴样增强因子1(LEF1)、细胞周期蛋白D1、基质金属蛋白酶2(MMP2)和血管内皮生长因子(VEGF)的蛋白表达;通过酶联免疫吸附测定(ELISA)评估VEGF和血管内皮钙黏蛋白释放,同时检测MUVECs的迁移及管腔形成情况。
在成骨分化过程中,miR-10a表达明显下调。miR-10a过表达抑制MC3T3-E1细胞的成骨分化,有效降低MUVECs的增殖、迁移、VEGF表达、血管内皮钙黏蛋白浓度及体外管腔形成,而miR-10a沉默则增强这些过程。进一步的机制分析表明,miR-10a过表达在蛋白质和转录水平均降低β-连环蛋白,而用Wnt信号激活剂LiCl预处理可部分减弱miR-10a过表达对成骨细胞分化和血管生成的抑制作用。
我们的研究结果表明,miR-10a通过调节β-连环蛋白表达,在MC3T3-E1细胞的成骨分化及MUVECs的促血管生成活性中起抑制作用,这代表了一种治疗骨再生相关疾病的新的潜在治疗靶点。