健骨方对破骨细胞形成和成骨细胞增殖分化的影响

目的　探讨健骨方水提物对破骨细胞分化及成骨细胞增殖分化的影响。方法　制备健骨方水提物,通过MTT法测定药物对骨髓单核巨噬细胞（BMMs）细胞的毒性,采用核因子κB受体活化因子配体（RANKL）诱导BMMs分化形成破骨细胞,加入不同浓度药物进行干预,采用抗酒石酸酸性磷酸酶( TRACP) 染色法测定破骨细胞分化抑制作用,采用Western Blot 法测定RANKL诱导的NF-κB破骨细胞分化信号通路,运用RT-qPCR法测定信号通路下游破骨细胞分化关键基因NFATc1、C-FOS等的mRNA表达水平。以MC3T3-E1细胞作为前体成骨细胞,加入不同浓度药物进行干预,通过CCK8法测定细胞增殖能力、PNPP法检测碱性磷酸酶（ALP）活性、茜素红S染色法测定细胞矿化能力。结果　MTT法结果显示,健骨方细胞有毒性浓度大于500 μg/mL（P＜0.05）,破骨细胞分化抑制IC50为1.25 μg/mL。机制研究显示健骨方显著下调了RANKL-NF-κB信号通路中的p-P65、P53的蛋白表达（P＜0.05）,显著抑制了通路下游C-FOS、NFATc1等的mRNA表达水平（P＜0.01,P＜0.05）。此外,成骨细胞活性检测显示,健骨方能明显促进MC3T3-E1细胞增殖、提高ALP活性及增加成骨细胞钙化的能力。结论 健骨方具有抑制破骨细胞分化和促进成骨前体细胞增殖、分化、矿化的药效作用。其作用与抑制破骨细胞分化RANKL-NF-κB信号通路及其下游C-FOS、NFATc1等基因,上调成骨细胞分化促进因子CAL1A2、SPARC和FOSL1基因的表达有关。     

钛颗粒诱导破骨细胞分化过程中活化T细胞核因子c1的表达

目的探讨钙调磷酸酶（CN）／活化T细胞核因子（NFAT）途经在磨损颗粒诱导破骨细胞分化调节中的作用。方法MTT法检测11R—VIVIT肽和钛（Ti）颗粒对小鼠骨髓单核／巨噬细胞系细胞（BMMs）活力的影响;RT—PCR法分析Ti颗粒诱导破骨细胞分化过程中NFATcl mRNA表达,并观察1R—VIVIT肽对Ti颗粒诱导NFATcl表达的影响;TRAP染色进行破骨细胞分化鉴定。结果11R—VIVIT肽和Ti颗粒均不影响体外培养中的BMMs活力;Ti颗粒显著刺激破骨细胞分化（P〈0.01）和NFATcl mRNA表达;应用11R—VIVIT肽阻断CN／NFAT途径可显著抑制Ti颗粒诱导的NFATcl表达。结论Ti颗粒刺激BMMs向破骨细胞分化;其作用机制可能与激活CN／NFAT途径有关。     

成骨细胞分化调控因子研究进展

成骨细胞具有维持骨骼结构,调控骨矿化和破骨细胞的功能,其分化受多种因子影响.Wnt信号转导通路中Wnt- 10b、Wnt-3a蛋白与成骨细胞分化关系密切;骨形态发生蛋白(BMP)信号通路中BMP-2、BMP-13等蛋白双向调控成骨细胞分化,维护骨量平衡,BMP还能通过调控Osx、Smad1等促进成骨细胞分化;3磷脂酰肌...     

成骨细胞特异性钙黏蛋白基因转染对人骨髓基质干细胞成骨分化影响的研究

目的 观测成骨细胞特异性钙黏蛋白(Cad-Ⅱ)基因转染对人骨髓基质干细胞(hBMSCs)成骨分化的影响. 方法把脂质体介导的Cad-Ⅱ cDNA转染体外分离培养的hBMSCs,检测Cad-Ⅱ蛋白表达变化,并对比观测转染组和单纯成骨诱导组在培养3,7、14、21 d时,hBMSCs碱性磷酸酶(ALP)和骨钙索的表达变化. 结果 转染组和成骨诱导组3 d后开始有ALP的阳性染色,呈棕黑色,7 d开始有骨钙索的阳性染色并随培养时间延长逐渐增多,但各时间点转染组ALP浓度(P=0.008)和骨钙素染色阳性数(P=0.023)均显著高于单纯成骨诱导组.转染组和成骨诱导组从14 d后开始有红色的刚件染色矿化结节出现,结节数目随时间推移而增多. 结论 Cad-Ⅱ基因转染可促进hBMSCs向成骨细胞的分化.     

羟基磷灰石掺锶对成骨细胞增殖分化及矿化影响的实验研究

[目的]探讨羟基磷灰石(HA)中掺锶对成骨细胞增殖、分化和矿化的影响,以及HA材料中适宜的掺锶量。[方法]用掺锶量分别为1%,5%和10%的HA生物陶瓷粉末及纯HA生物陶瓷粉末制备的浸提液培养SD大鼠成骨细胞,在不同时间点检测成骨细胞增殖、碱性磷酸酶(ALP)活性、核心结合因子(cbfal)基因表达,以及矿化结节形成的情况。[结果]各组成骨细胞的增殖无明显差别(P0.05);细胞培养第14、21d,掺锶各组成骨细胞的ALP活性、cbfalmRNA表达,及矿化结节数量等方面均显著高于HA组(P0.01),其中以掺锶量5%组最高,但与10%组相比无显著差异。[结论]HA中掺锶能上调成骨细胞cbfalmRNA的表达,促进成骨细胞分泌碱性磷酸酶,从而促进成骨细胞的分化、矿化,促进骨形成。详细的作用机制及HA中最佳的掺锶量尚需进一步的研究。     

环指蛋白11调控Akt信号通路促进BMSCs成骨分化的机制研究北大核心CSCD

目的研究BMSCs成骨分化过程中环指蛋白11(ring finger protein 11,RNF11)对Akt信号通路的调节作用,为进一步阐明BMSCs成骨分化机制和用于临床治疗提供思路。方法从健康人体新鲜骨髓中分离培养BMSCs并传代,取第4代细胞经流式细胞术,成骨、成软骨和成脂诱导培养鉴定后用于实验。BMSCs成骨诱导分化培养0~14 d,通过茜素红染色和ALP染色检测其成骨分化程度,并用Western blot法检测RNF11蛋白表达。取第4代BMSCs,分为空白对照组(A组)、空载慢病毒(Lv-NC)组(B组)和敲低RNF11(Lv-ShRNF11)组(C组),成骨诱导分化培养0~14 d,采用Western blot检测RNF11蛋白表达,茜素红染色和ALP染色检测其成骨分化程度,14 d实时荧光定量PCR(real-time fluorescence quantitative PCR,qRT-PCR)检测BMSCs成骨标志物Runx2、骨钙素(osteocalcin,OCN)及骨桥蛋白(osteopontin,OPN)的mRNA相对表达量;采用Western blot检测Akt、Smad1/5/8及β-catenin信号通路蛋白相对表达量,以磷酸化前后比值表示。为研究RNF11对Akt信号通路的影响机制,取第4代BMSCs分为Lv-NC转染组(A1组)、Lv-ShRNF11转染组(B1组)和添加Akt信号通路激活剂SC79的Lv-ShRNF11转染组(C1组),14 d时采用Western blot检测RNF11和Akt信号通路蛋白相对表达量,茜素红染色、ALP染色及qRT-PCR检测成骨相关指标。结果流式细胞术及成骨、成软骨和成脂诱导培养鉴定显示分离培养细胞为BMSCs。RNF11蛋白相对表达量随成骨分化时间延长而逐渐增加(P<0.05);下调RNF11后,茜素红和ALP染色示C组相较于A、B组BMSCs成骨分化程度降低,qRT-PCR检测示Runx2、OCN、OPN mRNA相对表达量减少(P<0.05)。随成骨分化时间延长,RNF11与Akt信号通路蛋白相对表达量均上升(P<0.05)。下调RNF11后,C组相较于A、B组,其Akt信号通路蛋白相对表达量显著降低(P<0.05),而对Smad1/5/8以及β-catenin信号通路蛋白相对表达量无明显影响(P>0.05)。B1、C1组相较于A1组,其RNF11蛋白相对表达量减少(P<0.05),B1组相较于A1、C1组,其Akt信号通路蛋白相对表达量降低(P<0.05);茜素红与ALP染色示C1组BMSCs成骨分化程度稍低于A1组(P>0.05),而明显高于B1组(P<0.05);qRT-PCR检测示C1组Runx2、OCN、OPN mRNA相对表达量稍低于A1组(P>0.05),而明显高于B1组(P<0.05)。结论RNF11通过正向调控Akt信号通路激活水平促进BMSCs向成骨细胞分化。RNF11可作为提高BMSCs修复骨缺损疗效以及治疗骨代谢病的潜在靶点。     

钙敏感受体缺失对小鼠成骨细胞增殖与分化的影响及机制研究

目的 探讨钙敏感受体(CaSR)在小鼠成骨细胞增殖与分化中的作用,以及Wnt信号通路在其促进成骨细胞增殖及分化过程中的调节作用. 方法 取新生同窝野生型小鼠(对照组)和CaSR敲除纯合子小鼠(实验组)各4只,分离培养颅骨成骨细胞并传至第3代,分别于培养2、4、6、8d时采用CCK-8法测定细胞的吸光度(OD)值,检测成骨细胞碱性磷酸酶(ALP)的活性.取培养6d的细胞行实时荧光定量-聚合酶链反应(RT-qPCR)检测核心结合因子(Runx2)、ALP、骨钙素(OCN)、核激活因子受体配体(RANKL)、骨保护素(OPG)及β-链蛋白的mRNA基因表达水平;采用Western Blot检测β-链蛋白、Wnt-5a、胰岛素样生长因子-1(IGF-1)、Runx2的蛋白表达水平. 结果 培养6d时对照组和实验组成骨细胞的OD值(1.55±0.05、1.26±0.02)和ALP活性[(0.023±0.002)、(0.017±0.001)U/mg· prot]均达到峰值,与其他时间点比较差异均有统计学意义(P＜0.05);同一时间点实验组成骨细胞的OD值和ALP活性均低于对照组,差异有统计学意义(P＜0.05).与对照组比较,培养6d时实验组成骨细胞的Runx2、ALP、OCN、RANKL/OPG、β-链蛋白的mRNA表达水平,以及β-链蛋白、Wnt-5a、IGF-1、Runx2的蛋白表达水平均显著降低,两组比较差异均有统计学意义(P＜0.05). 结论 CaSR缺失将导致成骨细胞的增殖和分化障碍,其机制可能与经典的Wnt信号通路抑制有关.     

cAMP/PKA信号通路介导人脂肪干细胞成骨分化的体外试验

目的 研究环腺苷酸(cAMP)/蛋白激酶A(PKA)信号通路对脂肪干细胞(ADSCs)成骨分化的影响.方法 在成骨细胞培养基中加入cAMP/PKA信号通路的激动剂db-cAMP和抑制剂H-89,观察成骨细胞分化、PKA的活化及下游调节蛋白CREB的磷酸化和成骨基因表达的变化.结果 db-cAMP促进PKA的活化,上调CREB的磷酸化和相关基因表达的变化,促进ADSCs的成骨分化,同时以上作用可被PKA抑制剂H-89有效地阻断.结论 cAMP/PKA是介导人ADSCs成骨分化的重要信号通路.     

GCM1通过激活Wnt3a/β-catenin信号通路改善绝经后骨质疏松症

目的 探究GCM1对小鼠胚胎成骨细胞前体细胞（MC3T3-E1）成骨分化及矿化的影响。方法 实验设置control组、BMP2诱导组、BMP2+ov-NC组、MP2+ov-GCM1组、BMP2+sh-NC组、BMP2+sh-GCM1组,BMP2用于诱导细胞成骨分化。通过碱性磷酸酶(ALP)染色及茜素红染色检测GCM1对MC3T3-E1成骨分化及矿化的影响;通过Western blot检测成骨分化相关蛋白及Wnt3a/β-catenin蛋白的表达变化。结果 GCM1在绝经后骨质疏松症患者血清中低表达。过表达GCM1能够促进BMP2诱导MC3T3-E1的成骨分化和矿化,而抑制GCM1表达则抑制了BMP2诱导MC3T3-E1的成骨分化和矿化。此外,过表达GCM1增加了Wnt3a/β-catenin蛋白表达,激活Wnt3a/β-catenin信号通路,抑制GCM1表达则与上述结果相反。结论 GCM1在绝经后骨质疏松症患者血清中低表达,过表达GCM1则可能通过激活Wnt3a/β-catenin信号通路、促进MC3T3-E1成骨分化及矿化,进而改善绝经后骨质疏松症。     

成骨与破骨细胞促红细胞生成素肝细胞受体B4/肝配蛋白B2双向信号通路

成骨细胞与破骨细胞以直接接触的方式共同调控骨重建平衡,这也决定了两者的不可分割性。最新研究表明前破骨细胞肝配蛋白(Ephrin)B2与成骨细胞膜上促红细胞生成素肝细胞受体(Eph)B4受体的直接接触来调控骨稳态平衡。具有EphrinB2配体的前破骨细胞可通过直接接触具有EphB4受体的前成骨细胞从而触发各自相应的下游信号转导分子。通过激活成骨细胞膜表面Eph受体而起正向作用,进一步去抑制下游信号转导分子RhoA活性促进前体细胞分化成熟。反之,EphrinB2配体的激活起到反向作用,抑制破骨相关转录因子的C-fos/NFATc1转录级联反应来抑制前破骨细胞的分化,磨损颗粒导致的骨溶解会使破骨细胞上EphrinB2配体表达明显升高,并且会促进NFATc1的高表达,可以通过这种双向信号的机制来减弱甚至是抑制磨损颗粒导致的破骨细胞的进一步分化。     

Cyclosporin A elicits dose-dependent biphasic effects on osteoblast differentiation and bone formation

Cyclosporin A (CsA) is thought to prevent immune reactions after organ transplantation by inhibiting calcineurin (Cn) and its substrate, the Nuclear Factor of Activated T Cells (NFAT). A dichotomy exists in describing the effects of CsA on bone formation. The concept that the suppression of Cn/NFAT signaling by CsA inhibits bone formation is not entirely supported by many clinical reports and laboratory animal studies. Gender, dosage and basal inflammatory activity have all been suggested as explanations for these seemingly contradictory reports. Here we examine the effects of varying concentrations of CsA on bone formation and osteoblast differentiation and elucidate the role of NFATc1 in this response. We show that low concentrations of CsA (< 1 μM in vitro and 35.5 nM in vivo) are anabolic as they increase bone formation, osteoblast differentiation, and bone mass, while high concentrations (> 1 μM in vitro and in vivo) elicit an opposite and catabolic response. The overexpression of constitutively active NFATc1 inhibits osteoblast differentiation, and treatment with low concentrations of CsA does not ameliorate this inhibition. Treating osteoblasts with low concentrations of CsA (< 1 μM) increases fra-2 gene expression and protein levels in a dose-dependent manner as well as AP-1 DNA-binding activity. Finally, NFATc1 silencing with siRNA increases Fra-2 expression, whereas NFATc1 overexpression inhibits Fra-2 expression. Therefore, NFATc1 negatively regulates osteoblast differentiation, and its specific inhibition may represent a viable anabolic therapy for osteoporosis.     

Blockade of JNK and NFAT pathways attenuates orthopedic particle‐stimulated osteoclastogenesis of human osteoclast precursors and murine calvarial osteolysis

Particles released from orthopedic implants attract immune host defense cells to the bone‐implant interface and contribute to development of inflammation. The inflammatory microenvironment supports recruitment and differentiation of osteoclasts, the primary culprit of osteolysis. Therefore, understanding the complex signals that contribute to osteoclastogenesis and osteolysis is a sensible approach to design strategies to inhibit bone loss. The signaling cascades that coordinate osteoclastogenesis have been widely investigated. These include MAP kinases, Akt/PI3K pathway, NF‐κB signal transduction pathway, and NFAT pathway. We have recently reported that polymethylmethacrylate (PMMA) particles activate the NFAT pathway in murine osteoclast precursors and that NFAT inhibitors dose‐dependently block PMMA‐induced osteoclastogenesis. In the current study, we examined the role of JNK and NFATc1 in mice in response to PMMA particles using murine calvaria model. We show that locally administered MAPK/JNK inhibitor SP600125 and calcineurin/NFAT inhibitor cyclosporine‐A effectively blocked PMMA‐induced osteolysis in murine calvaria. To buttress the clinical relevance of JNK/NFATc1‐based regulation of PMMA‐induced osteoclastogenesis, we evaluated the effect of PMMA using human macrophages. We demonstrate that SP600125 and cyclosporine‐A abolished particle‐induced osteoclastogenesis in human osteoclast progenitors retrieved from patients undergoing total hip replacement. Thus JNK and NFATc1 appear to act as significant mediators of orthopedic particle‐induced osteolysis in humans. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:67–72, 2012     

Kinetics of polymethylmethacrylate particle-induced inhibition of osteoprogenitor differentiation and proliferation.

Periprosthetic bone loss induced by implant wear debris may be a combined effect of osteolysis and reduced bone formation resulting from particle-induced suppression of osteoprogenitor differentiation. This study investigated the time-dependent effects of polymethylmethacrylate (PMMA) particles on the osteogenic capability of bone marrow osteoprogenitor cells during the early phase of differentiation. Murine bone marrow cells were challenged with PMMA particles (0.30% v/v) on the first day of growth in osteogenic medium. Particles were removed from culture after 1, 3, and 5 days, respectively, after which cell growth in osteogenic medium was continued until the 15th day. Bone marrow osteoprogenitor cells exposed to particles during the first 5 days of differentiation showed complete, irreversible inhibition of proliferation, alkaline phosphatase expression, and mineralization. Osteoprogenitors exposed to particles for more than 5 days showed the same degree of inhibition, while those exposed to particles for less than 5 days showed a diminished inhibitory response. Conditioned medium from particle-treated cells did not suppress osteogenic development, demonstrating that suppression of osteogenesis was not due to secreted inhibitory factors. This study has shown that the early phase of osteoprogenitor differentiation is a crucial time period during which exposure to PMMA particles causes irreversible inhibition of osteogenesis.     

Polymethylmethacrylate particles inhibit osteoblastic differentiation of MC3T3‐E1 osteoprogenitor cells

Orthopedic wear debris has been implicated as a significant inhibitory factor of osteoblast differentiation. Polymethylmethacrylate (PMMA) particles have been previously shown to inhibit the differentiation of osteoprogenitors in heterogeneous murine marrow stromal cell cultures, but the effect of PMMA particles on pure osteoprogenitor populations remains unknown. In this study, we challenged murine MC3T3‐E1 osteoprogenitor cells with PMMA particles during their initial differentiation in osteogenic medium. MC3T3‐E1 cultures challenged with PMMA particles showed a gradual dose‐dependent decrease in mineralization, cell number, and alkaline phosphatase activity at low particle doses (0.038–0.150% v/v) and complete reduction of these outcome parameters at high particle doses (≥0.300% v/v). MC3T3‐E1 cultures challenged with a high particle dose (0.300% v/v) showed no rise in these outcome parameters over time, whereas cultures challenged with a low particle dose (0.075% v/v) showed a normal or reduced rate of increase compared to controls. Osteocalcin production was not significantly affected by particles at all doses tested. MC3T3‐E1 cells grown in conditioned medium from particle‐treated MC3T3‐E1 cultures showed a significant reduction in mineralization only. These results indicate that direct exposure of MC3T3‐E1 osteoprogenitors to PMMA particles results in suppression of osteogenic proliferation and differentiation. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:932–936, 2008     

Osteogenic potential of postnatal skeletal muscle-derived stem cells is influenced by donor sex.

This study compared the osteogenic differentiation of F-MDSCs and M-MDSCs. Interestingly, M-MDSCs expressed osteogenic markers and underwent mineralization more readily than F-MDSCs; a characteristic likely caused by more osteoprogenitor cells within the M-MDSCs than the F-MDSCs and/or an accelerated osteogenic differentiation of M-MDSCs. INTRODUCTION: Although therapies involving stem cells will require both female and male cells, few studies have investigated whether sex-related differences exist in their osteogenic potential. Here, we compared the osteogenic differentiation of female and male mouse skeletal muscle-derived stem cells (F- and M-MDSCs, respectively), a potential cell source for orthopedic tissue engineering. MATERIALS AND METHODS: F- and M-MDSCs were stimulated with bone morphogenetic protein (BMP)4, followed by quantification of alkaline phosphatase (ALP) activity and expression of osteogenic genes. F- and M-MDSCs were also cultured as pellets in osteogenic medium to evaluate mineralization. Single cell-derived colonies of F- and M-MDSCs were stimulated with BMP4, stained for ALP, and scored as either Low ALP+ or High ALP+ to detect the presence of osteoprogenitor cells. F- and M-MDSCs were transduced with a BMP4 retrovirus (MDSC-BMP4 cells) and used for the pellet culture and single cell-derived colony formation assays. As well, F- and M-MDSC-BMP4 cells were implanted in the intramuscular pocket of sex-matched and sex-mismatched hosts, and bone formation was monitored radiographically. RESULTS AND CONCLUSIONS: When stimulated with BMP4, both F- and M-MDSCs underwent osteogenic differentiation, although M-MDSCs had a significantly greater ALP activity and a larger increase in the expression of osteogenic genes than F-MDSCs. In the pellet culture assay, M-MDSCs showed greater mineralization than F-MDSCs. BMP4 stimulation of single cell-derived colonies from M-MDSCs showed higher levels of ALP than those from F-MDSCs. Similar results were obtained with the MDSC-BMP4 cells. In vivo, F-MDSC-BMP4 cells displayed variability in bone area and density, whereas M-MDSC-BMP4 cells showed a more consistent and denser ectopic bone formation. More bone formation was also seen in male hosts compared with female hosts, regardless of the sex of the implanted cells. These results suggest that M-MDSCs may contain more osteoprogenitor cells than F-MDSCs, which may have implications in the development of cellular therapies for bone healing.