慢病毒沉默Piezo1蛋白与人骨髓间充质干细胞成骨分化及TAZ的表达

Effect of lentiviral silencing of Piezo1 on osteogenic differentiation and TAZ expression in human bone marrow mesenchymal stem cells

背景:Piezo1作为机械敏感蛋白与成骨分化密切相关,TAZ也被证明参与调节成骨分化,但Piezo1调控人骨髓间充质干细胞成骨分化时TAZ是否参与其中目前尚不明确,故研究其具体机制对防治股骨头坏死具有重要意义。目的:探讨Piezo1对人骨髓间充质干细胞成骨分化及TAZ表达的影响。方法:构建靶向Piezo1的siRNA,转染至293T细胞,通过RT-qPCR检测其沉默效率并筛选出Piezo1-Homo-2337进行包装,使用荧光染色检测其最佳感染复数值。Piezo1沉默重组慢病毒进一步被转染至人骨髓间充质干细胞中,通过RT-qPCR、Western blot检测其沉默效果;通过茜素红染色、碱性磷酸酶活性分析、免疫荧光染色、RT-qPCR及Western blot检测分析沉默Piezo1对人骨髓间充质干细胞成骨分化能力及TAZ表达的影响。结果与结论:①与正常组、阴性对照组比较,转染si-Piezo1后人骨髓间充质干细胞中Piezo1的mRNA及蛋白水平明显降低;②与阴性对照组比较,si-Piezo1组碱性磷酸酶活性明显降低,钙沉积明显减少;③与阴性对照组比较,si-Piezo1组成骨相关基因Runx2、OPN、DLX5、osteocalcin、β-catenin及TAZ的mRNA水平明显降低。si-Piezo1组TAZ、β-catenin的蛋白表达明显降低;相反,si-Piezo1组p-TAZ、p-β-catenin的蛋白表达明显增加;④与阴性对照组比较,免疫荧光染色结果提示si-Piezo1组人骨髓间充质干细胞中TAZ、β-catenin的表达较少;⑤结果表明Piezo1可促进人骨髓间充质干细胞的成骨分化,沉默Piezo1后人骨髓间充质干细胞的成骨能力明显降低,同时TAZ的表达也同样降低。

BACKGROUND:Piezo1,a mechanosensitive protein,is tightly connected to osteogenic differentiation,and it has been demonstrated that TAZ has a role in regulating osteogenic differentiation.It is unclear whether TAZ participates in the regulation of osteogenic differentiation of human bone marrow mesenchymal stem cells by Piezo1,so it is crucial to investigate its unique mechanism to prevent osteonecrosis of the femoral head.OBJECTIVE:To elucidate what function Piezo1 plays in osteogenic differentiation and TAZ expression in human bone marrow mesenchymal stem cells.METHODS:The siRNA targeting Piezo1 was constructed and transfected into 293T cells.The silencing efficiency was detected by RT-qPCR.The selected Piezo1-Home-2337 was packaged according to the silencing efficiency,and its optimal multiplicity of infection value was assayed by immunofluorescence staining.The packaged Piezo1 silencing recombinant lentivirus was transfected into human bone marrow mesenchymal stem cells,and its silencing effect was detected by RT-qPCR and western blot assay.Alizarin red staining,alkaline phosphatase activity analysis,immunofluorescence staining,RT-qPCR and western blot assay were utilized to analyze the effect of silencing Piezo1 on the osteogenic differentiation of human bone marrow mesenchymal stem cells.RESULTS AND CONCLUSION:(1)The mRNA and protein levels of Piezo1 in human bone marrow mesenchymal stem cells transfected by si-Piezo1 were decreased significantly,with a statistically significant difference compared with normal and negative control groups.(2)The alkaline phosphatase activity in the si-Piezo1 group was much lower and the calcium deposition in the si-Piezo1 group was significantly reduced compared with the negative control group.(3)The mRNA levels of osteogenesis-related genes including Runt-related transcription factor 2(Runx2),osteopontin(OPN),distal-less homeobox 5(DLX5),osteocalcin,β-catenin and Tafazzin(TAZ)in the si-Piezo1 group were significantly decreased compared with the negative control group.Afterward,the expression levels of TAZ andβ-catenin protein in the si-Piezo1 group were down-regulated significantly compared with the negative control group,whereas the expression levels of p-TAZ and p-β-catenin protein in the si-Piezo1 group had the opposite condition.(4)The results of immunofluorescence staining showed that the expression of TAZ andβ-catenin in human bone marrow mesenchymal stem cells in the si-Piezo1 group was less compared with the negative control group.(5)These findings indicate that Piezo1 can promote the osteogenic differentiation of human bone marrow mesenchymal stem cells.The osteogenic ability of human bone marrow mesenchymal stem cells is significantly reduced after silencing Piezo1,and the expression of TAZ is also reduced.