Bone tissue engineering may be hindered by underlying osteoporosis because of a decreased osteogenic ability of autologous seed cells and an unfavorably changed microenvironment in these patients. Epigenetic regulatio...Bone tissue engineering may be hindered by underlying osteoporosis because of a decreased osteogenic ability of autologous seed cells and an unfavorably changed microenvironment in these patients. Epigenetic regulation plays an important role in the developmental origins of osteoporosis; however, few studies have investigated the potential of epigenetic therapy to improve or rescue the osteogenic ability of bone marrow mesenchymal stem cells(BMMSCs) under osteoporotic conditions. Here, we investigated pargyline, an inhibitor of lysine-specific demethylase 1(LSD1), which mainly catalyzes the demethylation of the di- and mono-methylation of H3K4. We demonstrated that 1.5 mmol·Lpargyline was the optimal concentration for the osteogenic differentiation of human BMMSCs. Pargyline rescued the osteogenic differentiation ability of mouse BMMSCs under osteoporotic conditions by enhancing the dimethylation level of H3K4 at the promoter regions of osteogenesis-related genes. Moreover, pargyline partially rescued or prevented the osteoporotic conditions in aged or ovariectomized mouse models, respectively. By introducing the concept of epigenetic therapy into the field of osteoporosis, this study demonstrated that LSD1 inhibitors could improve the clinical practice of MSC-based bone tissue engineering and proposes their novel use to treat osteoporosis.展开更多
背景:目前认为低氧诱导因子1α是维持机体细胞内氧稳态的最重要调控因子之一,骨形态发生蛋白6是成骨活性最强的骨形态发生蛋白之一,实验拟构建二者共表达的骨髓间充质干细胞系,以研究细胞在低氧状态下的耐受及功能受益问题。目的:探讨...背景:目前认为低氧诱导因子1α是维持机体细胞内氧稳态的最重要调控因子之一,骨形态发生蛋白6是成骨活性最强的骨形态发生蛋白之一,实验拟构建二者共表达的骨髓间充质干细胞系,以研究细胞在低氧状态下的耐受及功能受益问题。目的:探讨体外模拟低氧环境下低氧诱导因子1α和骨形态发生蛋白6协同过表达骨髓间充质干细胞的成骨和成血管生物学特性。方法:分离培养鉴定SD大鼠骨髓间充质干细胞,将已构建好的携带有骨形态发生蛋白6和低氧诱导因子1α双基因的腺病毒真核表达载体共同感染骨髓间充质干细胞,在体积分数为21%O_2,2%O_2条件下分别进行培养,并以常氧状态下未转染的骨髓间充质干细胞作为对照组,RT-qPCR检测各组细胞HIF-1α、VEGF、BMP-6、GLUT-1、SIRT-1、OCN、RUNX2、AKP的m RNA水平。各组骨髓间充质干细胞与人脐静脉内皮细胞共培养后,观察体外小管形成能力;各组骨髓间充质干细胞经成骨诱导培养基干预后,碱性磷酸酶染色及茜素红染色鉴定成骨效果。结果与结论:(1)流式细胞仪检测结果显示第4代骨髓间充质干细胞高表达CD29、CD90、CD44,低表达CD45、CD11、CD34;(2)低氧组骨髓间充质干细胞VEGF、GLUT-1、SIRT-1、OCN、RUNX2、AKP m RNA表达水平高于常氧组(P<0.01);(3)低氧组小管形成数量要明显高于对照组,差异有非常显著性意义(P<0.01);(4)低氧组细胞出现更多的钙结节及圆形矿化结节;(5)上述结果表明,低氧诱导因子1α与骨形态发生蛋白6协同过表达骨髓间充质干细胞在体外低氧环境下具有更强的血管生成及成骨分化能力。展开更多
The rapid degradation of magnesium(Mg)-based implants in physiological environment limits its clinical applications, and alloying treatment is an effective way to regulate the degradation rate of Mg-based materials. I...The rapid degradation of magnesium(Mg)-based implants in physiological environment limits its clinical applications, and alloying treatment is an effective way to regulate the degradation rate of Mg-based materials. In the present study, three Mg alloys, including Mg-0.8Ca(denoted as ZQ), Mg-0.8Ca-5Zn-1.5Ag(denoted as ZQ71) and Mg-0.8Ca-5Zn-2.5Ag(denoted as ZQ63), were fabricated by alloying with calcium(Ca), zinc(Zn) and silver(Ag). The results obtained from electrochemical corrosion tests and in vitro degradation evaluation demonstrated that the three Mg alloys exhibited distinct corrosion resistance, and ZQ71 exhibited the lowest degradation rate in vitro among them. After addition of Zn and Ag, the antibacterial potential of Mg alloys was also enhanced. The in vitro cell experiments showed that all the three Mg alloys had good biocompatibility. After implantation in a rat femoral defect, ZQ71 showed significantly higher osteogenic activity and bone substitution rate than ZQ63 and ZQ, due to its higher corrosion resistance as well as the stimulatory effects of the released metallic ions. In addition, the average daily degradation rate of each Mg alloy in vivo was significantly higher than that in vitro, as could be due to the implantation site located in the highly vascularized trabecular region. Importantly, the correlations between the in vitro and in vivo degradation parameters of the Mg alloys were systematically analyzed to find out the potential predictors of the in vivo degradation performance of the materials. The current work not only evaluated the clinical potential of the three biodegradable Mg alloys as bone grafts but also provided a feasible approach for predicting the in vivo degradation behavior of biodegradable materials.展开更多
Although Ni-Ti-O nanopores(NPs) can be fabricated by anodization of mechanically polished NiTi alloys, the top disordered layer is difficult to remove thus hindering the functionality of the Ni-Ti-O NPs. In this work,...Although Ni-Ti-O nanopores(NPs) can be fabricated by anodization of mechanically polished NiTi alloys, the top disordered layer is difficult to remove thus hindering the functionality of the Ni-Ti-O NPs. In this work, an electropolishing(EP) pretreatment was performed on the NiTi substrate prior to anodization to thoroughly expose the NPs. Our results show that the EP pretreatment for 5 min perfectly removes the top disordered layer on the Ni-Ti-O NPs to expose the underlying NPs and consequently, the corrosion resistance and antibacterial ability are enhanced. The exposed NPs can elongate bone marrow mesenchymal stem cells, which may be responsible for the upregulated alkaline phosphatase activity, secretion of Type I collagen, and extracellular matrix mineralization. These results suggest that EP is a desirable pretreatment before anodization of the NiTi alloys because the irregular surface layer on the Ni-Ti-O NPs can be removed to enhance the corrosion resistance and biological functions.展开更多
基金supported by grants from the National Natural Science Foundation of China(81200763 to WG and 81070809 to YZ)the Program for New Century Excellent Talents(NCET)at the University from Ministry of Education of China(NCET-11-0026)+1 种基金the PKU School of Stomatology for Talented Young Investigators(PKUSS20150107)the Construction Program for the National Key Clinical Specialty from the National Health and Family Planning Commission of China(2011)
文摘Bone tissue engineering may be hindered by underlying osteoporosis because of a decreased osteogenic ability of autologous seed cells and an unfavorably changed microenvironment in these patients. Epigenetic regulation plays an important role in the developmental origins of osteoporosis; however, few studies have investigated the potential of epigenetic therapy to improve or rescue the osteogenic ability of bone marrow mesenchymal stem cells(BMMSCs) under osteoporotic conditions. Here, we investigated pargyline, an inhibitor of lysine-specific demethylase 1(LSD1), which mainly catalyzes the demethylation of the di- and mono-methylation of H3K4. We demonstrated that 1.5 mmol·Lpargyline was the optimal concentration for the osteogenic differentiation of human BMMSCs. Pargyline rescued the osteogenic differentiation ability of mouse BMMSCs under osteoporotic conditions by enhancing the dimethylation level of H3K4 at the promoter regions of osteogenesis-related genes. Moreover, pargyline partially rescued or prevented the osteoporotic conditions in aged or ovariectomized mouse models, respectively. By introducing the concept of epigenetic therapy into the field of osteoporosis, this study demonstrated that LSD1 inhibitors could improve the clinical practice of MSC-based bone tissue engineering and proposes their novel use to treat osteoporosis.
文摘背景:目前认为低氧诱导因子1α是维持机体细胞内氧稳态的最重要调控因子之一,骨形态发生蛋白6是成骨活性最强的骨形态发生蛋白之一,实验拟构建二者共表达的骨髓间充质干细胞系,以研究细胞在低氧状态下的耐受及功能受益问题。目的:探讨体外模拟低氧环境下低氧诱导因子1α和骨形态发生蛋白6协同过表达骨髓间充质干细胞的成骨和成血管生物学特性。方法:分离培养鉴定SD大鼠骨髓间充质干细胞,将已构建好的携带有骨形态发生蛋白6和低氧诱导因子1α双基因的腺病毒真核表达载体共同感染骨髓间充质干细胞,在体积分数为21%O_2,2%O_2条件下分别进行培养,并以常氧状态下未转染的骨髓间充质干细胞作为对照组,RT-qPCR检测各组细胞HIF-1α、VEGF、BMP-6、GLUT-1、SIRT-1、OCN、RUNX2、AKP的m RNA水平。各组骨髓间充质干细胞与人脐静脉内皮细胞共培养后,观察体外小管形成能力;各组骨髓间充质干细胞经成骨诱导培养基干预后,碱性磷酸酶染色及茜素红染色鉴定成骨效果。结果与结论:(1)流式细胞仪检测结果显示第4代骨髓间充质干细胞高表达CD29、CD90、CD44,低表达CD45、CD11、CD34;(2)低氧组骨髓间充质干细胞VEGF、GLUT-1、SIRT-1、OCN、RUNX2、AKP m RNA表达水平高于常氧组(P<0.01);(3)低氧组小管形成数量要明显高于对照组,差异有非常显著性意义(P<0.01);(4)低氧组细胞出现更多的钙结节及圆形矿化结节;(5)上述结果表明,低氧诱导因子1α与骨形态发生蛋白6协同过表达骨髓间充质干细胞在体外低氧环境下具有更强的血管生成及成骨分化能力。
基金financially supported by InterGovernmental S&T Cooperation Project Between China and Romania (2018LMNY003)Sichuan Science and Technology Innovation Team of China (2019JDTD0008)the Fundamental Research Funds for the Central Universities (2021SCU12071)。
文摘The rapid degradation of magnesium(Mg)-based implants in physiological environment limits its clinical applications, and alloying treatment is an effective way to regulate the degradation rate of Mg-based materials. In the present study, three Mg alloys, including Mg-0.8Ca(denoted as ZQ), Mg-0.8Ca-5Zn-1.5Ag(denoted as ZQ71) and Mg-0.8Ca-5Zn-2.5Ag(denoted as ZQ63), were fabricated by alloying with calcium(Ca), zinc(Zn) and silver(Ag). The results obtained from electrochemical corrosion tests and in vitro degradation evaluation demonstrated that the three Mg alloys exhibited distinct corrosion resistance, and ZQ71 exhibited the lowest degradation rate in vitro among them. After addition of Zn and Ag, the antibacterial potential of Mg alloys was also enhanced. The in vitro cell experiments showed that all the three Mg alloys had good biocompatibility. After implantation in a rat femoral defect, ZQ71 showed significantly higher osteogenic activity and bone substitution rate than ZQ63 and ZQ, due to its higher corrosion resistance as well as the stimulatory effects of the released metallic ions. In addition, the average daily degradation rate of each Mg alloy in vivo was significantly higher than that in vitro, as could be due to the implantation site located in the highly vascularized trabecular region. Importantly, the correlations between the in vitro and in vivo degradation parameters of the Mg alloys were systematically analyzed to find out the potential predictors of the in vivo degradation performance of the materials. The current work not only evaluated the clinical potential of the three biodegradable Mg alloys as bone grafts but also provided a feasible approach for predicting the in vivo degradation behavior of biodegradable materials.
基金financially supported by the Fund for Shanxi ‘‘1331 Project’’ Key Innovative Research Team (No.PY201809)the Program for the Innovative Talents of Higher Education Institutions of Shanxi (PTIT)+1 种基金the Natural Science Foundation of Shanxi Province (No. 201801D121093)Hong Kong Research Grant Council (RGC) General Research Funds (GRF)(No. City U11205617)。
文摘Although Ni-Ti-O nanopores(NPs) can be fabricated by anodization of mechanically polished NiTi alloys, the top disordered layer is difficult to remove thus hindering the functionality of the Ni-Ti-O NPs. In this work, an electropolishing(EP) pretreatment was performed on the NiTi substrate prior to anodization to thoroughly expose the NPs. Our results show that the EP pretreatment for 5 min perfectly removes the top disordered layer on the Ni-Ti-O NPs to expose the underlying NPs and consequently, the corrosion resistance and antibacterial ability are enhanced. The exposed NPs can elongate bone marrow mesenchymal stem cells, which may be responsible for the upregulated alkaline phosphatase activity, secretion of Type I collagen, and extracellular matrix mineralization. These results suggest that EP is a desirable pretreatment before anodization of the NiTi alloys because the irregular surface layer on the Ni-Ti-O NPs can be removed to enhance the corrosion resistance and biological functions.
