Osteoinductivity of partially purified bovine, ostrich and emu bone morphogenetic proteins in vitro

The aim of this study was to observe the osteogenic activity of native bone morphogenetic proteins (BMPs) obtained from different species including bovine, ostrich and emu sources in order to compare mammalian and avian BMPs. Rat mesenchymal progenitor marrow stromal cells and pre-osteoblastic C2C12 cell cultures, were exposed to the native BMPs and alkaline phosphatase (ALP) and creatine kinase (CK) levels were determined by assay. The results showed that the ALP activity in C2C12 cultures was elevated by bovine BMP by 2- to 10-fold (p < 0.05-0.001) from day 3 during 14 days. There were no significant differences in avian BMP related elevations of ALP activity except with ostrich BMPs at day 14 (p < 0.05). However, exposure of MSCs cultures to BMPs derived from bovine, ostrich or emu sources resulted in elevated ALP from day 3 (p < 0.05). Bovine BMP resulted in more ALP elevation than with either of the avian BMPs. All of BMPs elevated Creatine kinase (CK) activity from day 1 and climbed until peaking at day 7. Compared with control cultures, CK was elevated more with exposure to emu BMP and was more elevated with greater statistical significance than with bovine and ostrich BMP before day 5. These higher levels remained until day 14 (p < 0.05). The results of this study suggest that both bovine and avian BMPs are able to stimulate osteogenesis in mature osteoblasts in vitro. The strongest synergistic effect on osteogenesis was detected in cells stimulated with bovine BMP. Avian BMPs had lower effects on ALP and CK activity, emu BMP being more effective than ostrich BMP.     

The role of BMP-6, IL-6, and BMP-4 in mesenchymal stem cell-dependent bone development: effects on osteoblastic differentiation induced by parathyroid hormone and vitamin D(3)

Human bone marrow-derived mesenchymal stem cells (MSCs) represent an ideal source for cell therapy for inherited and degenerative diseases, bone and cartilage repair, and as target for gene therapy. The role of the combination of human parathyroid hormone (PTH) and vitamin D(3) in bone formation and mineralization has been established in several osteoblast cell culture studies. The aim of the present study was to evaluate the role of this hormonal combination alone and in the presence of bone morphogenetic protein-4 (BMP-4) or-6 (BMP-6) in inducing osteogenic differentiation of human MSC. Human MSC derived from adult normal bone marrow that are positive for CD29, CD44, CD105, and CD166 and negative for CD14, CD34, and CD45, were treated with the PTH and 1,25-dihydroxyvitamin D(3) in the presence and absence of recombinant human BMP-4 or BMP6. PTH and vitamin D(3) induced high levels of expression of two key markers of bone formation: osteocalcin and alkaline phosphatase by MSCs. BMP-6 but not BMP-4 increased osteocalcin expression induced by PTH and vitamin D(3). Both BMPs enhanced calcium formation in MSC cultures and this response was potentiated by PTH and vitamin D(3). The present results revealed a novel potent effect of PTH and vitamin D(3) plus BMPs in inducing bone development by human MSCs. These results may facilitate therapeutic utility of MSCs for bone disease and help clarify mechanisms involved in stem cell-mediated bone development.     

Embryonic Stem Cell Marker Expression Pattern in Human Mesenchymal Stem Cells Derived from Bone Marrow, Adipose Tissue, Heart and Dermis

Mesenchymal stem cells (MSCs) have been isolated from a variety of human tissues, e.g., bone marrow, adipose tissue, dermis, hair follicles, heart, liver, spleen, dental pulp. Due to their immunomodulatory and regenerative potential MSCs have shown promising results in preclinical and clinical studies for a variety of conditions, such as graft versus host disease (GvHD), Crohn’s disease, osteogenesis imperfecta, cartilage damage and myocardial infarction. MSC cultures are composed of heterogeneous cell populations. Complications in defining MSC arise from the fact that different laboratories have employed different tissue sources, extraction, and cultivation methods. Although cell-surface antigens of MSCs have been extensively explored, there is no conclusive evidence that unique stem cells markers are associated with these adult cells. Therefore the aim of this study was to examine expression of embryonic stem cell markers Oct4, Nanog, SOX2, alkaline phosphatase and SSEA-4 in adult mesenchymal stem cell populations derived from bone marrow, adipose tissue, dermis and heart. Furthermore, we tested whether human mesenchymal stem cells preserve tissue-specific differences under in vitro culture conditions. We found that bone marrow MSCs express embryonic stem cell markers Oct4, Nanog, alkaline phosphatase and SSEA-4, adipose tissue and dermis MSCs express Oct4, Nanog, SOX2, alkaline phosphatase and SSEA-4, whereas heart MSCs express Oct4, Nanog, SOX2 and SSEA-4. Our results also indicate that human adult mesenchymal stem cells preserve tissue-specific differences under in vitro culture conditions during early passages, as shown by distinct germ layer and embryonic stem cell marker expression patterns. Studies are now needed to determine the functional role of embryonic stem cell markers Oct4, Nanog and SOX2 in adult human MSCs.     

Enhancement of the in vivo osteogenic potential of marrow/hydroxyapatite composites by bovine bone morphogenetic protein

A composite of marrow mesenchymal stem cells and porous hydroxyapatite (HA) has in vivo osteogenic potential. To investigate factors enhancing the osteogenic potential of marrow/HA composites, we prepared a bone morphogenetic protein (BMP) fraction from the 4M guanidine extract of bovine bone by heparin-sepharose affinity chromatography. Marrow/HA composites or composites containing marrow mesenchymal stem cells, BMP, and HA (marrow/BMP/HA composites) were implanted subcutaneously in 7-week-old male Fischer rats. BMP/HA composites and HA alone were also implanted. The implants were harvested after 2, 4, or 8 weeks and were prepared for histological and biochemical studies. Histological examination showed obvious de novo bone formation together with active osteoblasts at 2 weeks, as well as more extensive bone formation at 4 and 8 weeks in many pores of the marrow/BMP/HA composites. The marrow/HA composites did not induce bone formation at 2 weeks, but there was moderate bone formation at 4 weeks. At 2 weeks, only marrow/BMP/HA composites resulted in intensive osteogenic activity, judging from alkaline phosphatase and osteocalcin expression at both the protein and gene levels. These results indicate that the combination of marrow mesenchymal stem cells, porous HA, and BMP synergistically enhances osteogenic potential, and may provide a rational basis for their clinical application, although further in vivo experiment is needed.     

Spry1在miR-21调控人骨髓间充质干细胞成骨分化中的作用

背景：前期研究发现,miR-21在骨髓间充质干细胞成骨分化中表达上升,但是miR-21在骨髓间充质干细胞成骨分化中的作用及分子机制尚不明确。 目的：验证miR-21的靶基因Spry1,探明Spry1在人骨髓间充质干细胞成骨分化中的作用。 方法：荧光素酶报告验证miR-21靶基因Spry1,Western Blot检测Spry1在人骨髓间充质干细胞成骨过程的表达。构建Spry1慢病毒表达载体,感染人骨髓间充质干细胞。碱性磷酸酶、茜素红染色、RT-PCR和Western Blot分析Spry1高表达后人骨髓间充质干细胞成骨能力的改变。 结果与结论：荧光素酶报告提示Spry1为miR-21的靶基因,在人骨髓间充质干细胞成骨过程中表达量下降。上调Spry1能够抑制人骨髓间充质干细胞的成骨分化。结果表明Spry1作为miR-21的靶基因负向调控人骨髓间充质干细胞的成骨分化,在骨形成过程发挥着重要作用。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

腺病毒介导的人骨形态发生蛋白2基因转染骨髓间充质干细胞

背景：骨髓间充质干细胞作为骨、软骨创伤缺损及退变修复的种子细胞越来越受到关注。 目的：分析人骨形态发生蛋白2基因转染对白色封闭群大鼠(SD大鼠)骨髓间充质干细胞的影响。 方法：分离纯化SD大鼠骨髓间充质干细胞并体外扩增,通过腺病毒载体介导人骨形态发生蛋白2基因转染骨髓间充质干细胞,分别通过荧光显微镜观察荧光表达情况及蛋白质水平来测定转染后人骨形态发生蛋白2的表达,碱性磷酸酶定量测定鉴定成骨活性及MTT法评估人骨形态发生蛋白2转染对骨髓间充质干细胞的影响。 结果与结论：从SD大鼠骨髓提取物中分离培养的细胞形态为梭形,呈铺路石状、漩涡状生长,经流式细胞仪检测及多项分化能力鉴定符合骨髓间充质干细胞的特征;经转染人骨形态发生蛋白2基因后,骨髓间充质干细胞表达人骨形态发生蛋白2、碱性磷酸酶;MTT法检测转染人骨形态发生蛋白2基因后,骨髓间充质干细胞增殖能力明显增强(P < 0.05)。说明人骨形态发生蛋白2基因转染骨髓间充质干细胞后可以持续、高效表达人骨形态发生蛋白2和碱性磷酸酶,在体外明显促进骨髓间充质干细胞的增殖。     

酪蛋白激酶2相互作用蛋白1调控骨质疏松大鼠骨髓间充质干细胞的成骨能力北大核心

背景:目前对酪蛋白激酶2相互作用蛋白1(casein kinase 2-interaction protein-1,CKIP-1)分子机制的体外研究主要集中在基因敲除小鼠来源成骨细胞或骨髓间充质干细胞,鲜见报道骨质疏松模型大鼠来源骨髓间充质干细胞中CKIP-1表达的研究。目的:探讨下调CKIP-1基因前后骨质疏松状态骨髓间充质干细胞成骨分化能力的变化。方法:用维甲酸诱导雌性SD大鼠骨质疏松模型,采用全骨髓贴壁法体外培养骨质疏松组、正常组大鼠骨髓间充质干细胞。成骨诱导后进行茜素红染色、碱性磷酸酶染色及实时定量RT-PCR检测骨桥蛋白、Runx2 mRNA的相对表达,实时定量RT-PCR检测成骨诱导过程中2组细胞中CKIP-1的动态表达;通过基因转染沉默CKIP-1基因,成骨诱导后进行茜素红染色、碱性磷酸酶染色及实时定量RT-PCR检测骨桥蛋白、Runx2 mRNA的相对表达。结果与结论:①与正常组相比,骨质疏松组骨髓间充质干细胞茜素红染色钙结节定量、碱性磷酸酶活性及骨桥蛋白、Runx2的mRNA水平降低(P<0.05),骨质疏松组骨髓间充质干细胞中CKIP-1基因动态表达水平总体偏高;②与未下调CKIP-1的骨质疏松组骨髓间充质干细胞相比,下调CKIP-1基因表达后,骨质疏松组骨髓间充质干细胞茜素红染色钙结节定量、碱性磷酸酶活性及骨桥蛋白、Runx2的mRNA水平明显升高(P<0.05);③结果表明,维甲酸诱导的骨质疏松大鼠骨髓间充质干细胞成骨能力降低,下调CKIP-1基因可以部分提高其成骨分化能力。     

Interaction of mesenchymal stem cells and osteoblasts for in vitro osteogenesis

It has recently been reported that bone marrow-derived mesenchymal stem cells (MSCs), which are systemically administrated to different species, undergo site-specific differentiation. This suggests that the tissue specific cells may cause or promote the differentiation of the MSCs toward their cell type via a cell-to-cell interaction that is mediated not only by hormones and cytokines, but also by direct cell-to-cell contact. In this study, in order to assess the possible synergistic interactions for osteogenesis between the two types of cells, the MSCs derived from rabbit bone marrow were co-cultured with rat calvarial osteoblasts in direct cell-to-cell contact in a control medium (CM) and in an osteogenic medium (OM). The cell number, alkaline phosphatase activity, and amount of calcium deposition were assayed in the cultures of MSCs, osteoblasts, and co-cultures of them in either OM or CM for up to 40 days. The cell numbers and the alkaline phosphatase activities in the co-culture were somewhere in between those of the osteoblast cultures and the MSC cultures. The amounts of deposited calcium were lower in the co-culture compared to those of the other cultures. This suggests that there are little synergistic interactions during osteogenesis in vitro between the rat osteoblasts and rabbit MSCs.     

Comparative effects of nacre water-soluble matrix and dexamethasone on the alkaline phosphatase activity of MRC-5 fibroblasts

In this study we demonstrate, for the first time, that dexamethasone and BMP-2 stimulated alkaline phosphatase (ALP) activity in MRC-5 fibroblasts, a cell line derived from human fetal lung. Previously we reported that the water-soluble matrix (WSM) of nacre obtained from the inner shell layer of the oyster Pinctada maxima, promoted an increase in ALP activity that was dose-dependent. In this work, we show that the effect of WSM is also time-dependent. As a comparison, the effect of WSM was also tested in bone marrow stromal cells because marrow and other bone surface-derived osteoblast stem cells have the inherent direct potential for osteogenesis. WSM promotes cell proliferation and ALP activity when tested with bone marrow cells in concentrations between 135 and 540 microg protein/mL. The effect of WSM on ALP activity of bone marrow stromal cells is similar to that obtained by dexamethasone. These results imply that MRC-5 fibroblasts respond to differentiating factors that promote osteoblastic phenotype in bone-derived cell cultures.     

龟板含药血清促进骨髓间充质干细胞骨形态发生蛋白4的表达

目的 龟板有促大鼠骨髓间充质干细胞(MSCs)增殖作用,本研究观察龟板含药血清对MSCs中骨形态发生蛋白4(BMP4)表达的影响.方法 使用密度梯度法分离大鼠骨髓间充质干细胞进行培养,传代纯化,在基础培养液中添加不同浓度龟板含药血清和对照血清,用荧光定量PCR和原位杂交方法检测BMP4 mRNA表达,用ELISA、免疫组织化学和免疫荧光组织化学法结合激光扫描共聚焦显微镜技术检测BMP4蛋白表达的变化.结果 BMP4蛋白和mRNA表达相一致,龟板含药血清以浓度依赖方式促进MSC的BMP4 mRNA及其蛋白表达.结论 龟板含药血清以时效和量效依赖性促进BMP4在MSCs的表达,可能与龟板促MSCs增殖作用有关.     

力生长因子促进骨髓间充质干细胞向成骨细胞的分化

BACKGROUND:Mechano growth factor has the potential to activate muscle satellite cells and promote myogenic cell growth, and has dual roles in maintaining bone mass and repairing bone defects. OBJECTIVE:To explore the mechanism underlying osteogenic differentiation of rabbit bone marrow mesenchymal stem cells promoted by the mechano growth factor. METHODS:The best concentration and time of mechano growth factor to promote osteogenic differentiation of rabbit bone marrow mesenchymal stem cells were detected by MTT. The mRNA and protein expressions of alkaline phosphatase and osteocalcin were detected by qPCR and western blot, respectively. The phosphorylation level of AKT and mTOR were detected by western blot assay. RESULTS AND CONCLUSION:The best concentration and time of mechano growth factor was 45 μg/L and 5 days for promoting the osteogenic differentiation of rabbit bone marrow mesenchymal stem cells. The expressions of alkaline phosphatase and osteocalcin at mRNA and protein levels were highest after 4-hour intervention with 45 μg/L mechano growth factor, and meanwhile, the phosphorylation levels of mTOR and AKT were also highest. These findings indicate that the mechano growth factor can promote the differentiation of rabbit bone marrow mesenchymal stem cells into osteoblasts via PI3K/AKT pathway, and its best concentration and time are 45 μg/L and 4 hours, respectively.     

动静态不同牵张条件下大鼠骨髓间充质干细胞的增殖与分化

背景：在体外和体内关于细胞对于不同的机械牵张反应的大量研究表明,牵张能够刺激成骨。然而鲜有文献报道不同的牵张方式对于同种细胞的影响有何不同。 目的：比较不同机械牵张方式对大鼠骨髓间充质干细胞的影响。 方法：分离培养大鼠骨髓间充质干细胞,应用自行研制的牵张装置对骨髓间充质干细胞分别施加动态、静态和模拟临床的混合牵张牵张刺激,分别检测3种刺激方式下骨髓间充质干细胞的增殖能力、碱性磷酸酶活性及Runx2基因的mRNA表达,并测量细胞骨钙素的分泌情况。 结果与结论：静态牵张组与对照组相比,细胞增殖能力提高18.67%,碱性磷酸酶活性、Runx2表达及骨钙素分泌无明显差异;动态牵张组相对于对照组,细胞碱性磷酸酶活性提高60.33%, Runx2表达上升49.67%,细胞外骨钙素的分泌提高了48%,然而细胞增殖则受到了抑制;混合牵张组相对于对照组,细胞增殖能力稍有上升但无统计学差异,其对碱性磷酸酶活性、Runx2表达以及骨钙素的分泌有一定的促进作用,但没有动态牵张组明显。结果提示,静态牵张能够显著刺激骨髓间充质干细胞的增殖,而动态牵张对于刺激骨髓间充质干细胞成骨向分化作用更为明显,混合牵张方式对于细胞增殖及成骨分化均有一定的促进作用。     

In Vitro Osteogenesis of Synovium Mesenchymal Cells Induced by Controlled Release of Alendronate and Dexamethasone from a Sintered Microspherical Scaffold

In vitro osteogenesis was successfully achieved with synovium-derived mesenchymal stem cells (SMSCs), which intrinsically have a strong chondrogenic tendency, by in situ release of alendronate (AL) and dexamethasone (Dex) from poly(lactic-co-glycolic acid) (PLGA)/hydroxyapatite (HA) sintered microspherical scaffold (PLGA/HA-SMS). Cumulative release profiles of AL and Dex from PLGA/HA-SMS and the influence on SMSCs osteogenic commitment were investigated. SMSCs seeded in Al-/Dex-loaded PLGA/HA-SMS (PLGA/HA-Com-SMS) exhibited significant osteogenic differentiation, as indicated by high yields of alkaline phosphatase (ALP) and bone calcification. In addition, mechanical properties (compressional) of PLGA/HA-Com-SMSs were also evaluated and approved. In conclusion, by promoting osteogenic commitment of SMSCs in vitro, this newly designed controlled-release system opens a new door to bone reparation and regeneration.     

Glucocorticoid‐induced differentiation of primary cultured bone marrow mesenchymal cells into adipocytes is antagonized by exogenous Runx2

Lin L, Dai S‐Dong, Fan G‐Yu. Glucocorticoid‐induced differentiation of primary cultured bone marrow mesenchymal cells into adipocytes is antagonized by exogenous Runx2. APMIS 2010; 118: 595–605. Long‐term clinical use of glucocorticoids often causes the serious side effect of non‐traumatic avascular osteonecrosis. The aim of this study was to examine the effects and mechanisms of a glucocorticoid, dexamethasone (Dex), on differentiation of primary cultured rat bone marrow mesenchymal cells (BMCs). We also tried to block the inhibitory effects of Dex on osteoblast differentiation. Adipocyte markers (peroxisome proliferator‐activated receptorγ‐2 and aP2) were increased in response to Dex treatment in a dose‐ and time‐dependent manner, while osteoblastic markers [Runx2, COL 1, osterix, alkaline phosphatase (ALP) and OC] were down‐regulated, consistent with ALP and osteocalcin promoter activity. To validate the effects of Runx2 on the expression of osteogenesis and adipocyte genes, pCMV/Flag‐Runx2 was transfected into BMCs, and relevant markers were detected after 10^?7 M Dex treatment for 48 h. The results indicated that Dex treatment induced adipogenic differentiation and suppressed proliferation. No significant difference was detected in expressions of these genes between Runx2‐transfected cells and Dex‐treated BMCs. These data suggest that Dex primarily induced adipocyte differentiation of BMCs. Exogenous Runx2 can antagonize the effect of Dex on osteoblast differentiation.