核因子KB受体活化因子对骨质吸收的影响

核因子kB受体活化因子（RANK）的研究多集中在它所参与组成的信号传导通路及其调节破骨细胞增殖分化作用的机制方面。RANK编码基因在转录、翻译最终形成有活性的RANK过程中受到多种因素的调节，其中任何一个环节的异常都会给破骨细胞的增殖分化带来影响，并最终导致出现以骨质吸收异常为特征的疾病。RANK与许多骨质破坏性疾病存在密切关系，近年在治疗这些疾病方面围绕RANK的研究逐步展开，并在体外试验中取得了很大进展，为进一步临床试验奠定基础。该文就近年RANK研究成果作一综述，并探讨控制异常骨质吸收的新途径。     

破骨细胞分化机制的研究进展

破骨细胞为人体主要的骨吸收细胞,对骨骼的发育及维持具有重要作用,同时破骨细胞的异常活化对多种溶骨性疾病的发展具有重要作用;明确破骨细胞的分化机制,可为多种骨代谢性疾病提供新的治疗策略及药物靶点。大量的实验对破骨细胞的分化机制进行了研究,并确认有一些基因为破骨细胞分化形成所必需,这些基因的缺失或突变将导致破骨细胞形成障碍,进而引起骨质硬化;并且由巨睡细胞集落刺激因子（macrophage colony stimulating factor,M-CSF)、核因子k B受体活化因子 配体（receptor Activator for Nuclear Factor-k B Ligand, RANKL)及免疫受体酪氨酸激活基序（immunoreceptor tyrosine-based activation motif,ITAM)介导的3条重要的信号通路参与其分化过程,3条信号通路相互作用,共同促进破骨细胞的分化形成,但RANKL如何激活ITAM信号通路,有待进一步研究,本文就破骨细胞分化机制的研究进展作一综述。     

致敏淋巴细胞对破骨细胞分化及骨吸收的影响

目的；研究致敏淋巴细胞对破骨细胞分化及骨吸收功能的影响。方法：从被骨水泥单体甲基丙烯酸甲酯（MMA）致敏的新西兰兔外周血中分离淋巴细胞并提取培养介质（LCM），分离培养兔颅骨成骨细胞和兔骨髓细胞，通过抗酒石酸酸性磷酸酶（TrACP)染色和骨磨片扫描电镜观察对破骨细胞进行鉴定。在成骨细胞与骨髓细胞的培养体系中，分别在无LCM，未经MMA刺激的LCM和经MMA刺激的LCM等3种情况下，进行成熟破骨细胞计数和TrACP活性检测。结果：骨髓细胞能够分化成破骨细胞并且能在骨磨片上形成骨吸收陷窝，致敏淋巴细胞培养介质能够明显促进破骨细胞数量的增加和TrACP的分泌，在加入MMA刺激后，这种作用更加显著。结论：致敏淋巴细胞能够促进骨髓破骨细胞的分化和骨吸收能力。     

阿司匹林对大鼠破骨细胞分化成熟和骨吸收活性的影响

目的 研究不同浓度阿司匹林对体外培养大鼠破骨细胞(Osteoclast,OC)分化成熟及骨吸收活性的影响.方法 建立由核激活因子受体配体(receptor activator of NF-κB ligand,RANKL)和巨噬细胞集落刺激因子(Macrophage colony stimulating factor,M-CSF)共同作用的大鼠破骨细胞骨髓诱导体系,将雌激素(10-6 mmol/L)和不同浓度的阿司匹林(0.25 mmol/L、0.5 mmol/L、1.0 mmol/L、1.5 mmol/L)分别作用于破骨细胞.诱导培养后分别对破骨细胞进行抗酒石酸酸性磷酸酶(The tartrate-resistant acid phosphatase,TRAP)染色,观察细胞形态,并计数破骨样细胞数量;将各组破骨细胞接种于骨磨片上,建立破骨细胞-骨磨片活性分析模型,于不同时间点对骨磨片进行光镜和扫描电镜观察,分析计算骨吸收陷窝面积.结果 与正常对照组相比,雌激素组破骨细胞数量和骨吸收陷窝面积低于正常对照组,差异有统计学意义(P＜0.05);且随着阿司匹林浓度的增加,阿司匹林组TRAP阳性多核破骨细胞数量、骨吸收陷窝面积逐渐减少直至消失,差异有统计学意义(P＜0.05).与雌激素组相比,低浓度阿司匹林组(0.25mmol/L)没有明显差异;但中、高浓度阿司匹林实验组(0.5mmol/L、1.0mmol/L、1.5mmol/L)破骨细胞数量和骨吸收陷窝面积减少,差异有统计学意义(P＜0.05).结论 阿司匹林对破骨细胞的分化成熟及骨吸收功能有抑制作用,且呈剂量依赖性,从而具有抗骨质疏松的作用.     

Genistein对破骨细胞分化和骨吸收功能的影响及其机制探讨

目的 探讨三羟异黄酮类药Genistein对破骨细胞性骨吸收的作用及其机制。方法 1，25(OH)2D3诱导小鼠骨髓细胞形成破骨样细胞，分别加入0moL／L、10^-9moL／L、10～moL／L、10^-7moL／L、10～moL／L、10^-5moL／LGenistein，于培养3，5和8d分别计数抗酒石酸酸性磷酸酶阳性细胞个数；于培养12d利用图像分析系统对骨吸收陷窝的面积进行测量分析。另从小鼠颅盖骨分离培养获得原代成骨细胞，分别加入0，10^-8，10^-7，10^-6和10^-5moL／LGenistein并以10^-9moL／L^-7 β雌二醇为对照，采用RT-PCR的方法检测Genistein对骨保护因子(osteoprotegerin，OPG)及破骨细胞分化因子(receptor activator of NF-κB ligand，RANKL)mRNA表达的影响。结果 利用1，25(OH)2D3成功诱导出破骨样细胞；随Genistein浓度增加，抗酒石酸酸性磷酸酶阳性细胞(单核、双核和多核)个数和骨吸收陷窝面积呈剂量依赖性减少。同时，应用Genistein后原代成骨细胞中OPG和RANKL的mRAN表达都有增强，但其最终效应表现为剂量依赖性和时间依赖性地增大OPG／RANKL的浓度比。结论 Genistein通过抑制破骨前体细胞分化来抑制其体外骨吸收功能，其分子机制与OPG／RANKL mRNA表达比值的升高有关。     

核因子κB受体活化因子对骨质吸收的影响

核因子κB受体活化因子(RANK)的研究多集中在它所参与组成的信号传导通路及其调节破骨细胞增殖分化作用的机制方面。RANK编码基因在转录、翻译最终形成有活性的RANK过程中受到多种因素的调节,其中任何一个环节的异常都会给破骨细胞的增殖分化带来影响,并最终导致出现以骨质吸收异常为特征的疾病。RANK与许多骨质破坏性疾病存在密切关系,近年在治疗这些疾病方面围绕RANK的研究逐步展开,并在体外试验中取得了很大进展,为进一步临床试验奠定基础。该文就近年RANK研究成果作一综述,并探讨控制异常骨质吸收的新途径。     

BM210955对破骨细胞骨吸收的抑制作用

细胞水平研究国产双磷酸盐药物－ＢＭ２１０９５５的骨吸收抑制作用。由１日龄ＳＤ大鼠四肢长骨分离破骨细胞（ＯＣ）并接种于牛皮质骨薄切片上,在不同浓度ＢＭ２１０９５５作用下培养,定时取骨片作ＴＲＡＰ免疫组化染色,计数阳性多核细胞后,经超声去除细胞后作甲苯胺蓝染色,光镜下作吸收陷窝计数,数据以ｘ±ｓ表示,并与对照比较作ｔ检验。结果显示：①ＢＭ２１０９５５能降低体外培养ＯＣ的数目,１０－８ｍｏｌ／Ｌ组的ＴＲＡＰ阳性多核细胞较对照组减少７３％,差异具有非常显著性,Ｐ＜０．０１。②ＢＭ２１０９５５抑制ＯＣ的陷窝形成能力,１０－１０、１０－８ｍｏｌ／Ｌ组的抑制率分别为７６．３２％和８７．９９％,均与对照有明显差异,Ｐ＜０．０１。③上述结果与剂量有关,剂量越高,抑制效应越明显     

破骨细胞骨吸收机制的研究进展

人体骨骼依赖于骨吸收和骨形成之间的动态平衡 ,当破骨细胞的骨吸收功能超过成骨细胞的骨形成作用后 ,这一平衡的失调将导致骨质疏松或骨质破坏。因妇女绝经、过量服用糖皮质激素等多种因素引起的骨质疏松 ,Ｐａｇｅｔ’ｓ病 ,以及癌症骨转移造成的骨破坏 ,都与破骨细胞异常活跃的分化增殖和骨吸收功能有关。因此 ,破骨细胞 (ｏｓｔｅｏｃｌａｓｔ,ＯＣ)是治疗上述疾病的靶细胞[1,2 ] 。1　破骨细胞分化形成的微环境ＯＣ是一种特殊类型的多核巨细胞 ,来源于ＣＤ3 4+ 的骨髓造血干细胞 ,其分化主要受骨髓基质细胞和成骨细胞所分泌的集落细胞…     

RANK信号调控破骨细胞分化与成熟的研究进展

破骨细胞来源于微环境造血前体细胞,它的生存、增殖、分化和激活需要巨噬细胞集落刺激因子(M-CSF)和核因子κB受体活化因子配体(RANKL)参与。RANKL与相应的RANK受体结合,从而刺激破骨前体细胞分化成为破骨细胞。这一过程由不同的调节蛋白和激酶来调控,并且依赖于RANKL-RANK信号。本文中,笔者总结了目前已知的在破骨细胞发生过程中调节RANK信号的机制。在早期阶段,RANK信号的调节通过募集调节蛋白如肿瘤坏死因子受体相关因子6(tumor necrosis factor receptor-associated factor 6, TRAF6),引起丝裂原活化蛋白激酶(mitogen-activated protein kinases, MAPKs)以及转录因子核因子κB(nuclear factor-κB, NF-κB)和激活蛋白-1(activator protein-1, AP-1)的活化。活化的NF-κB进一步激活调节破骨细胞生成的重要因子-T细胞核因子1(nuclear factor of activated T-cells cytoplasmic 1, NFATc1)。在信号传递的中间阶段,共刺激信号通过激活磷脂酶Cγ2(phospholipase Cγ2, PLCγ2)连同c-Fos/AP-1引起钙离子(Ca~(2+))振荡,同时Ca~(2+)信号促进NFATc1的产生。在破骨细胞生成的晚期阶段,NFATc1入核诱导大量的破骨细胞特异性靶基因的表达,从而使细胞融合并发挥其功能。     

致敏淋巴细胞对破骨细胞分化及骨吸收的影响

目的研究致敏淋巴细胞对破骨细胞分化及骨吸收功能的影响.方法从被骨水泥单体甲基丙烯酸甲酯(MMA)致敏的新西兰兔外周血中分离淋巴细胞并提取培养介质(LCM),分离培养兔颅骨成骨细胞和兔骨髓细胞,通过抗酒石酸酸性磷酸酶(TrACP)染色和骨磨片扫描电镜观察对破骨细胞进行鉴定.在成骨细胞与骨髓细胞的培养体系中,分别在无LCM,未经MMA刺激的LCM和经MMA刺激的LCM等3种情况下,进行成熟破骨细胞计数和TrACP活性检测.结果骨髓细胞能够分化成破骨细胞并且能在骨磨片上形成骨吸收陷窝,致敏淋巴细胞培养介质能够明显促进破骨细胞数量的增加和TrACP的分泌,在加入MMA刺激后,这种作用更加显著.结论致敏淋巴细胞能够促进骨髓破骨细胞的分化和骨吸收能力.     

不同氧环境中破骨细胞的发育分化和功能变化研究

目的 本实验拟观察不同氧浓度下破骨细胞诱导过程中的分化发育,寻找破骨细胞体外培养的适宜氧浓度,为骨转换平衡的修复提供依据.方法 取野生型C57B/L小鼠(2个月龄左右,雄性)骨髓进行破骨细胞的诱导培养.用RANKL(10ng/ml)和M-CSF(10ng/ml)联合的诱导方案,将小鼠骨髓中单核-巨噬细胞系体外诱导为破骨细胞样细胞.将原代破骨细胞置于20%O2、7%O2、2%O2下诱导培养,MOCP5不同氧浓度下普通培养.用MTT法检测MOCP5的增殖变化,用抗酒石酸酸性磷酸酶(TRAP)染色检测破骨细胞形成的变化,并进行TRAP阳性细胞计数,用象牙骨片骨吸收陷窝甲苯胺蓝染色检测破骨细胞骨吸收活性的变化.结果 骨髓中单核-巨噬细胞体外经RANKL和M-CSF联合诱导可分化为多核的破骨细胞样细胞,在诱导第3天细胞开始融合,第5天TRAP染色强阳性,第8天可见象牙骨片上形成圆形、椭圆形、腊肠形等多种形态的骨吸收陷窝.MTT检测显示MOCP5在20%O2培养时一直处于增殖状态,7%O2条件下由增殖期进入平台期,2%O2时增殖缓慢且没有规律.20%O2、7%O2、2%O2培养下形成的TRAP阳性破骨细胞数分别为22±5.97、34±2.97、7±1.39(P<0.05),原代诱导的破骨细胞在20%O2、7%O2、2%O2形成的骨吸收陷窝面积(μm2)分别为3892.28±1642.78、5356.7±1655.6、2573±994.48(P<0.05).结论 体外RANKL和M-CSF联合可将骨髓单核-巨噬细胞诱导成多核的破骨细胞样细胞作为破骨细胞的研究模型.常氧条件下破骨细胞的TRAP阳性细胞数和骨吸收活性均低于7%O2.7%O2培养下的破骨细胞更接近于体内生理状态的破骨细胞.     

甲状旁腺激素在体外对破骨细胞分化及骨重吸收能力的影响

目的 探讨甲状旁腺激素(PTH)在体外直接对破骨细胞(OCs)分化及骨吸收能力的影响，以及其与成骨细胞(OBs)中核因子kB受体激活剂受体配体(ligand of receptor activator of nuclear factor kappa B，RANKL)基因和OPG(osteoprotegerin)基因表达的关系。方法体外直接用PTH诱导C3h小鼠全骨髓分化出OCs，用牙片小坑法(pits assayr)观察OCs对骨的重吸收能力。并采用多重RT-PCR方法检测在不同PTH作用浓度和不同作用时间的条件下,OBs中RANKL基因和OPG基因的表达情况。结果(1)PTH在体外可诱导C3h小鼠全骨髓分化出OCs，且在一定浓度范围内，随着PTH增加，OCs的形成数目和骨组织的破坏程度随之增加；(2)在一定PTH浓度和时间范围内，OBs中的RANKL-mRNA及OPG-mRNA表达呈剂量依赖性和时间依赖性。结论 PTH在体外可通过诱导RANKL基因和OPG基因表达而直接影响OCs的分化和骨重吸收功能。     

Titanium particles stimulate bone resorption by inducing differentiation of murine osteoclasts

BACKGROUND: Loosening of orthopaedic implants is mediated by cytokines that elicit bone resorption and are produced in response to phagocytosis of implant-derived wear particles. This accelerated bone resorption could be due to increased osteoclastic activity, survival, or differentiation. Although a number of in vitro studies have shown that wear particles increase osteoclastic activity, the increase was less than twofold in all cases. The objective of the current study was to test the hypothesis that wear particles stimulate bone resorption by inducing osteoclast differentiation. METHODS: Conditioned media were prepared from murine marrow cells or human peripheral blood monocytes incubated in the presence or absence of titanium particles. The effects of conditioned media on osteoclast differentiation were examined with use of a recently developed assay in which osteoclast precursors are co-cultured with mesenchymal support cells. RESULTS: The present study showed that titanium particles induced both murine marrow cells and human peripheral blood monocytes to produce factors that stimulated osteoclast differentiation. The mean increase in osteoclast differentiation was 29.3+/-9.4-fold. The stimulation of osteoclast differentiation led to a parallel increase in bone resorption. The amount of stimulation was regulated in a dose-dependent manner by the concentration of both titanium particles and conditioned media. The stimulation of osteoclast differentiation required interactions between the cells and the particles themselves and, therefore, was not due to metal ions, soluble contaminants released from the particles, or submicrometer particles. In contrast, conditioned media from control cells incubated in the absence of titanium particles had no detectable effect on any of the examined parameters. CONCLUSIONS: The present study showed that titanium particles stimulate in vitro bone resorption primarily by inducing osteoclast differentiation. In contrast, the titanium particles had only small effects on osteoclast activity or survival.     

The effects of bisphosphonates on the resorption cycle of isolated osteoclasts

Binding sites for wheat germ agglutinin (WGA)-lectin have been shown to become revealed in the demineralized resorption lacunae that osteoclasts excavate on bone substrate. Peroxidase-conjugated WGA-lectin, which binds to bone matrix glycoconjugates and proteoglycans, was used in pit formation assays to assess the activity of isolated osteoclasts cultured on either 3-amino-1,1-hydroxy-propylidene-bisphosphonate (APD)-or dichloromethylene bisphosphonate (Cl₂MBP)-covered bone slices. Immunofluorescence and histochemical techniques were also used to study the effects of bone-bound bisphosphonates on isolated rat osteoclasts. Neither APD nor Cl₂MBP interfered with the special organization of actin or vinculin in osteoclasts when the cells were initializing their resorption cycle. After 24 hours of culture, the number of resorbing osteoclasts increased strongly on control slices, but remained low on either APD- or Cl₂MBP-treated slices. At this time, the actin and vinculin rings in osteoclasts also started to exhibit abnormal, more diffuse staining. Both bisphosphonates studied resulted in signs of cytotoxicity: the number of osteoclasts decreased on APD- or Cl₂MBP-covered bone during the course of the study and those remaining attached exhibited severe cytoplasmic retractions. The total areas of resorption remained at significantly lower levels in both experimental groups studied, and this was due to decreases in both the number and sizes of individual resorption pits. The size of the most extensive lacunae detected on the Cl₂MBP slices did not exceed 5x10³ m², whereas on the control slices, resorption pits bigger than 15x10^{3 2} were frequently discovered.     

The effects of extracellular pH on bone resorption by avian osteoclasts in vitro

It has previously been reported that low extracellular pH stimulates the excavation of resorption lacunae by rodent osteoclasts in vitro. Using avian bone cells in a similar in vitro assay we have demonstrated that osteoclast activity is optimal at pH 7.20-7.40 and is inhibited at extremes of pH (less than 7.10 and greater than 7.60). Over the first 24 h of incubation at low pH there may be an increase in osteoclastic resorption but to a lesser extent than that reported for rodent cells. However, after 24-30 h in culture there is little or no further increase in bone resorption, presumably due to a cytotoxic effect of low pH acting either on the osteoclast directly or via nonosteoclastic bone cells. In contrast to a previous report, in which preincubation of wafers for 24 h had no effect on bone resorption, we found that preincubation of bone substrates at pH 6.50 for longer periods enhances subsequent resorption at pH 7.20.     

The effect of insulin on bone resorption

the administration of crystalline insulin to thyroparathyroidectomized rats raised their calcium and phosphorus plasma levels. The plasma calcium gave a linear response between 31 and 250 mU of insulin/100 g body weight. The slope obtained is not significantly different from that obtained with parathyroid extract. The simultaneous administration of insulin and parathyroid extract to thyroparathyroidectomized rats affected the calcium and phosphorus plasma levels in an additive fashion. When chick embryo frontal bones were cultivatedin vitro with crystalline insulin the rate of resorption increased. Insulin increased the rate of glucose consumption by the explants and induced the accumulation of citrate in the culture medium. It is concluded that insulin stimulates bone resorption.     

二甲双胍对破骨细胞体外分化的影响

目的 探讨二甲双胍对破骨细胞体外分化的影响及其可能机制.方法 采用RANKL诱导鼠巨噬细胞系Raw264.7细胞破骨分化模型,给予不同浓度的二甲双胍(400 μmol/L、800 μmol/L和1000μmol/L)和雷帕霉素(100 hmol/L)处理后,通过抗酒石酸酸性磷酸酶(tartrate-resistant Acid Phosphatase,TRAP)染色和破骨细胞骨架结构荧光染色观察破骨细胞数量,骨吸收培养板观察骨陷窝面积,RT-PCR技术检测破骨细胞特异性基因TRAP、组织蛋白酶K、降钙素受体和金属基质蛋白酶-9的表达,ELISA法检测肿瘤坏死因子-α(tumor necrosis factor,TNF-α)表达水平,Western-b1ot检测c-Fos蛋白以及哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin complex l,mTORC1)信号通路下游底物S6K1 Thr389、S6 Ser235/236、4EBP1 Thr37/46的表达及磷酸化水平.结果 二甲双胍和雷帕霉素均可使RANKL诱导的破骨细胞数量减少,抑制破骨细胞特异性基因的表达、抑制TNF-α、c-Fos蛋白以及mTORC1信号通路下游底物S6K1 Thr389、S6 Ser235/236、4E-BP1 Thr37/46的磷酸化,且二甲双胍的抑制作用具有浓度依赖性.结论 二甲双胍可抑制RANKL诱导的破骨前体细胞分化,其机制可能与抑制TNF-α和c-Fos蛋白的生成,以及抑制mTORC1信号通路激活有关.

Abstract：

Objective To investigate the effects of mefformin on the differentiation of osteoclastas well as relative mechanism.Methods Raw264.7 cells from the murine macrophage cell line was used.Receptor activator of NF-κB ligand (RANKL) was used to stimulate osteoclast differentiation from Raw264.7 cells.Osteoclast differentiation was assessed by tartrate-resistant acid phosphatase (TRAP) and actin fluorescence staining and counting the TRAP-positive cells after exposure to different concentrations of mefformin (0 μmol/L,400 μmol/L,800 μmol/L and 1000 μmol/L) or rapamicin (100 nmol/L) in the presence of 50 ng/ml RANKL for 5 days.Bone-resorbing activity was evaluated by BD BioCoatTM OsteologicTM Bone Cell Culture System.The expression of osteoclast-specific genes like TRAP,capthesin K,calcitonin receptor (CTR) and matrix metalloproteinase (MMP-9) was evaluated by RT-PCR.The expression of tumor necrosis factor-α(TNF-ct) S6K1Thr389,S6 Ser235/236,4E-BP1Thr37/46 and c-Fos protein was evaluated by ELISA kit and Western blot analysis,respectively.Results Mefformin dose-dependently inhibited RANKL-stimulated osteoclasts differentiation in Raw264.7 cell culture,as manifested by decrease of TRAP-positive multinucleated cells and pit erosion area,down-regulation of TRAP,cathepsin K,CTR and MMP-9 mRNA and reduction of TNF-α and c-Fos protein expression.Further study revealed that RANKL activated mTOR complex 1(mTORC1) signaling,while mefformin impaired RANKL-stimulated mTORC1 signaling.Rapamycin,an mTORCl-specific inhibitor and immunosuppressive macrolides could also prevent RANKL-induced osteoclast differentiation and bone resorption in vitro.Conclusion Mefformin inhibits osteoclastogenesis in vitro,which may due to reduction of TNF-α and c-Fos protein expression,and mTORC1 signaling is involved in this process.