调控成骨细胞分化影响因子的研究进展

哺乳动物的骨骼处在骨形成和骨溶解的平衡中,这两个过程分别由成骨细胞和破骨细胞介导。成骨细胞可由间充质干细胞经过前成骨细胞发育而来,这个过程受到许多细胞因子的调控,包括促进成骨和抑制成骨。本篇综述主要介绍在成骨细胞分化过程中发挥重要调节作用的细胞因子。     

rhBMP-7对小鼠骨髓间充质干细胞向成骨细胞分化的影响

目的:观察重组人骨形成蛋白-7(rhBMP-7)对小鼠骨髓间充质干细胞(BMSCs)向成骨细胞分化的影响。方法:采用密度梯度离心法分离骨髓,体外培养扩增,获得小鼠骨髓间充质干细胞,贴壁培养至第3代,向培养液中加入rhBMP-7,培养5 d后进行碱性磷酸酶(ALP)染色,ALP活性与骨钙素(OC)含量检测,并用RT-PCR法分析成骨细胞标志基因骨钙素(OC)与Ⅰ型胶原(Col-Ⅰ)表达情况,Western blot法检测Ⅰ型胶原(Col-Ⅰ)蛋白的分泌量。结果:rhBMP-7诱导组的骨髓间充质干细胞的ALP染色强度、ALP活性及OC含量明显升高,OC与Col-Ⅰ的mRNA表达水平以及Col-Ⅰ的蛋白表达水平均明显提高。结论:rhBMP-7可促进体外培养的小鼠BMSCs向成骨细胞方向分化。     

中药龟板对Parkinson病大鼠模型BMP4表达的影响

为研究益肾中药龟板对Parkinson病(PD)模型大鼠骨形成蛋白4(BMP4)表达的影响,本研究将6-羟基多巴胺注入大鼠黑质建立PD大鼠模型,对模型大鼠行高、低剂量龟板水煎液口服治疗45d后,采用ELISA和RT-PCR方法进行血清中BMP4酶联免疫试验和脑黑质、纹状体中BMP4mRNA的检测。结果显示:PD模型组的BMP4表达明显降低,用龟板治疗后可以显著阻碍此趋势,而且高剂量组比低剂量组效果更为明显(P<0.05)。本研究结果提示,龟板有明显的促进BMP4及BMP4mRNA表达的作用。     

低氧条件下成骨细胞的增殖与分化

背景：低氧可通过多种途径作用于成骨细胞影响骨代谢,对骨生成、骨愈合等产生负面影响。 目的：观察低氧对体外培养大鼠成骨细胞增殖、分化的影响,并探讨其分子机制。 方法：分离培养新生Wistar大鼠颅盖骨成骨细胞,取第2代细胞分别在常氧(体积分数20%O₂)与低氧(体积分数3%O₂)条件下培养。 结果与结论：低氧组成骨细胞增殖、碱性磷酸酶活性、骨钙素水平及茜素红结节形成数量均明显低于常氧组(P < 0.05或  P < 0.01),说明缺氧条件对成骨细胞的增殖、分化及功能有抑制作用;低氧组骨形成发生蛋白2及Runx2表达低于常氧组(P < 0.05或P < 0.01),说明低氧条件下大鼠成骨细胞Runx2、骨形成发生蛋白2的表达受抑制。结果表明低氧可通过抑制大鼠成骨细胞的Runx2、骨形成发生蛋白2的表达进一步抑制成骨细胞的增殖与分化。     

脊髓缺血再灌注损伤对大鼠水通道蛋白4表达的影响

目的:在整体水平研究脊髓缺血再灌注损伤对大鼠水通道蛋白4表达水平的影响.方法:SD大鼠72只随机分为空白组、假手术组和SCⅡ组,每组24只.建立大鼠脊髓缺血再灌注损伤模型,并于1、3、5、7天四个时间点分别处死6只.BBB评分评价神经功能,Western blot和免疫荧光方法检测AQP4的表达情况.结果:空白对照组和假手术组在不同时间点的BBB评分均为21分,SCⅡ组的BBB评分在1天时最低,随时间推移逐渐增加,3天明显优于1天(P＜0.05),5天明显优于3天(P＜0.05),5天明显优于7天(P＜0.05).Western blot在34 kD及43 kD分子量处可见特异性条带,SCⅡ组早期AQP4的表达水平显著下降,即在1、3、5、7天四个时间点AQP4的表达显著低于空白对照组和假手术组,但呈逐渐增加趋势;在7天仍显著低于正常空白组和假手术组(P＜0.05).免疫荧光检测AQP4的表达变化趋势与Western blot的检测结果相似.结论:SCⅡ存在AQP4低表达,这可能是造成SCⅡ神经功能障碍的重要原因.     

茶多酚对脂多糖刺激下成骨细胞增殖分化的影响

背景：研究表明,茶多酚在牙周炎等疾病的研究中能发挥抗炎、抗氧化作用。目的：探讨茶多酚在脂多糖刺激下对小鼠成骨细胞增殖分化及氧化应激的影响。方法：体外培养小鼠成骨细胞MC3T3-E1,分4组处理：对照组常规培养;脂多糖组加入10μg/mL脂多糖,茶多酚组加入1μg/mL茶多酚,联合组加入10μg/mL脂多糖+1μg/mL茶多酚。采用MTT法检测细胞增殖情况,碱性磷酸酶试剂盒检测细胞碱性磷酸酶活性,偶氮偶联法检测细胞碱性磷酸酶染色程度,钙检测试剂盒检测细胞钙沉积量,超氧化物试剂盒检测细胞超氧化物含量,丙二醛试剂盒检测细胞丙二醛含量。结果与结论：(1)与对照组相比,脂多糖组成骨细胞增殖活性、碱性磷酸酶活性、钙沉积量降低(P <0.05),碱性磷酸酶染色程度降低(P <0.01),超氧化物和丙二醛含量增加(P <0.05);茶多酚组成骨细胞增殖活性、碱性磷酸酶活性、钙沉积量升高(P <0.05),碱性磷酸酶染色程度提高(P <0.01),超氧化物和丙二醛含量减少(P <0.05);(2)与脂多糖组相比,联合组成骨细胞增殖活性、钙沉积量升高(P <0.0...     

SIRT1对早期脑缺血大鼠水通道蛋白4表达的影响

目的:检测水通道蛋白4(AQP4)及沉默信息调节因子1(SIRT1)在脑缺血大鼠脑组织中的表达变化,探究SIRT1对AQP4的调节作用,明确二者在脑缺血及脑水肿发生发展中的作用。方法:雄性SD大鼠随机分成假手术组(sham组)和脑缺血模型组(MCAO组),其中MCAO组又分为6 h、12 h、24 h和48 h 4个时点组别。采用线栓法阻塞大脑中动脉建立局灶性脑缺血模型,于相应时点进行神经症状评分,Morris水迷宫检测大鼠学习认知功能,TTC染色观察脑梗死体积,干湿重法检测脑含水量的变化,HE染色观察大脑皮层周围组织神经细胞形态学变化,Western blot检测AQP4、SIRT1和基质金属蛋白酶9(MMP-9)的表达情况。结果:与sham组相比较,随着再灌注时间增加,MCAO组大鼠神经功能评分、脑梗死体积、脑组织通透性和脑组织含水量均持续增加,而大鼠学习认知功能则降低显著,HE染色显示脑缺血大脑皮层周围组织神经元细胞形态不规则,数目减少;Western blot实验结果显示AQP4表达水平呈增高趋势,SIRT1表达降低,MMP-9表达增高,MCAO-48 h组与sham组比较差异最明显(P0.01)。结论:脑缺血后,伴随脑组织损伤的加剧,SIRT1和MMP-9信号通路的表达激活影响了AQP4的表达活化,共同参与了脑水肿的形成。     

骨形成蛋白4对人胶质瘤干细胞增殖和凋亡的影响

目的 研究骨形成蛋白4(bone morphogenetic protein 4,BMP4)对人胶质瘤干细胞增殖和凋亡的影响.方法 在体外以重组人BMP4蛋白干预人胶质瘤U87细胞系来源的胶质瘤干细胞,免疫荧光鉴定胶质瘤干细胞,通过软琼脂克隆实验、流式细胞仪检测,观察BMP4对胶质瘤干细胞增殖和凋亡的影响.结果 BMP4能显著抑制胶质瘤干细胞的增殖能力,并诱导其凋亡.BMP4组增殖相关蛋白Cyclin D1 表达降低,抗凋亡蛋白Bcl-2表达明显降低,促凋亡蛋白Bax表达显著增多.结论 BMP4可显著抑制胶质瘤U87细胞系来源的胶质瘤干细胞的增殖能力,并诱导其凋亡.     

小鼠嗅球中水通道蛋白4表达缺失对抑郁发生的影响

目的:观察水通道蛋白4(AQP4)在小鼠嗅球中的表达情况,探讨AQP4表达缺失对小鼠抑郁发生的影响。方法:应用免疫荧光技术观察小鼠嗅上皮和嗅球中AQP4的表达,采用嗅觉电位(EOG)测定比较小鼠的嗅觉差异,悬尾试验(TST)和喷溅试验(ST)检测AQP4基因敲除(AQP4^-/-)小鼠与野生型(WT)小鼠的抑郁样行为,并分析抑郁行为与嗅觉电位的相关性。结果:免疫荧光检测发现AQP4在嗅上皮和嗅球神经纤维层和突触小球层均有不同程度表达; AQP4^-/-与WT小鼠相比,食物性嗅觉电位诱发实验的电位更低(P <0.01);抑郁行为学发现AQP4^-/-小鼠悬尾实验的不动时间较长、第一次梳理背部毛发潜伏时间较长以及梳理时间较短(P <0.01); AQP4^-/-小鼠嗅觉电位与悬尾不动时间、梳理潜伏时间呈负相关(P <0.05),与梳理背部毛发时间呈正相关性(P <0.05)。结论:AQP4表达在小鼠嗅鞘细胞膜上,其表达对于维持嗅觉信号的传递具有重要意义,AQP4基因敲除引起小鼠嗅觉的减退...     

水通道蛋白-4与脑水肿关系研究进展

脑水肿是指脑组织内的异常水分潴留，使脑体积增大，是多种疾病伴发的一种病理状态。脑水肿的非手术治疗的方法有渗透性利尿、高张盐水，亚低温治疗等，尚没有针对脑水肿分子机制的有效治疗。水通道蛋白（AQP）是膜水通道蛋白家族，为调节跨细胞水平衡的选择性孔道，迄今在哺乳动物中已发现13种水通道蛋白（AQPO-AQPl2）^[1]。     

IRAK-4 as the central TIR signaling mediator in innate immunity

Toll-like receptors (TLRs), which recognize pathogen-associated molecular patterns and members of the proinflammatory interleukin-1 receptor (IL-1R) family, share homologies in their cytoplasmic domains. Engagement of members of both of these families initiates a common intracellular signaling cascade, in which MyD88 and tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) are key adaptor proteins. Signaling between MyD88 and TRAF6 is mediated by members of the IL-1R-associated kinase (IRAK) family; however, the exact function of each IRAK protein remains controversial. IRAK-1 is required for the optimal transduction of IL-1R- and TLR-mediated signals, but IRAK-1 can be replaced by other IRAKs. Surprisingly, gene targeting studies show that the newest IRAK protein, IRAK-4, has an essential role in mediating signals initiated by IL-1R and TLR engagement. The kinase activity of IRAK-4 might be necessary to functionally modify IRAK-1 and perhaps other signal transducing substrates. Understanding the role of IRAK-4 in innate immunity will enable us to design novel strategies for therapeutic intervention in human infectious disease.     

Minimal structure of IRAK-1 to induce degradation of TRAF6

Excessive activation of Toll-like receptor (TLR) leads to sepsis. Inflammatory responses to various microbiological components are initiated via different TLR proteins, but all TLR signals are transmitted by TRAF6. We reported that TRAF6 associated with ubiquitinated IRAK-1 undergoes proteasome-mediated degradation, suggesting that IRAK-1 has a negative regulatory role in TLR signaling. Here, we investigated the minimal structural region of IRAK-1 needed for degradation of TRAF6. The IRAK-1 protein contains an N-terminal death domain (DD; amino acids 1–102), a serine/proline/threonine-rich ProST domain (amino acids 103–197), a central kinase domain with an activation loop (amino acids 198–522), and the C-terminal C1 and C2 domains (amino acids 523–712), which contain two and one putative TRAF6-binding (TB) sites, respectively. TRAF6 degradation was severely impaired by deletion of the DD or C1 domain, and a mutant (DC1) containing only the DD and C1 domains could induce TRAF6 degradation. IRAK-1 mutants lacking the N- or C-terminal amino acids of DD induced little degradation. Deletion or mutation of TB2 (amino acids 585–591) in the C1 domain also inhibited TRAF6 degradation. An IRAK-1 mutant possessing only DD and TB2 did not induce TRAF6 degradation, although a mutant in which a short spacer was inserted between DD and TB2 induced TRAF6 degradation, which and DC1-induced degradation were inhibited by proteasome inhibitors. All IRAK-1 mutants that induced TRAF6 degradation could be immunoprecipitated with TRAF6. Meanwhile, NF-κB activation was observed for all IRAK-1 mutants–including those that failed to induce degradation and was severely impaired only for a mutant carrying mutations in both TBs of C1. These results demonstrate that only DD and TB2 separated by an appropriate distance can induce TRAF6 degradation. Conformational analysis of this minimal structural unit may aid development of low molecular compounds that negatively regulate TLR signaling.     

IRAK-4 kinase activity is required for IRAK-4-dependent innate and adaptive immune responses

Interleukin-1 receptor-associated kinase (IRAK)-4 is a serine-threonine kinase that plays an important role in innate and adaptive immune responses. While the requirement of IRAK-4 kinase activity has been studied in the context of IL-1R signaling, it is not clear whether IRAK-4 requires its kinase function for all of its roles in the immune system. IRAK-4 kinase-dead knock-in (IRAK-4KD/KD) mice were generated to further elucidate whether IRAK-4 kinase activity is required for IRAK-4 to induce cytokine production. IRAK-4KD/KD mice were impaired in their ability to produce cytokines in response to in vivo challenge with lipopolysaccharide (LPS), a potent TLR4 ligand. Cytokine production was also reduced in macrophages and dendritic cells from IRAK-4KD/KD mice in response to LPS and other TLR ligands. In addition, adaptive immune responses were impaired in IRAK-4KD/KD mice. Although in vitro T cell proliferation in response to TCR activation was unaffected in IRAK-4-deficient mice, in vivo T cell responses to lymphocytic choriomeningitits virus infection were significantly impaired in IRAK-4-knockout mice or mice expressing the kinase-dead mutant of IRAK-4. Collectively, these results indicate that IRAK-4 kinase activity is required for IRAK-4-dependent signaling in innate and adaptive immunity.     

BMP-2通过诱导RBP4表达调控小鼠骨髓间充质细胞的成骨分化

目的　探讨视黄醇结合蛋白4（RBP4）在骨形态发生蛋白（BMP-2）诱导骨髓间充质干细胞（BMSCs）成骨分化中的作用。  方法　用重组人源BMP-2（rhBMP-2）诱导小鼠BMSCs成骨分化,采用Western-blot和qPCR检测成骨分化过程中RBP4表达情况;RNA干扰技术抑制RBP4表达,检测小鼠BMSCs成骨分化情况。  结果    qPCR和western-blot检测结果表明：rhBMP-2诱导小鼠BMSCs细胞7 d后,成骨分化明显,同时细胞RBP4表达水平显著升高;转染RBP4 siRNA 24 h后以rhBMP-2诱导7 d,小鼠BMSCs细胞成骨分化被显著抑制。   结论    BMP-2通过诱导RBP4表达,促进小鼠BMSCs的成骨分化。     

IRAK-4 kinase activity-dependent and -independent regulation of lipopolysaccharide-inducible genes

IRAK-4 kinase inactive (IRAK-4 KD) knock-in mice display defects in TLR- and IL-1 receptor signaling and are resistant to LPS-induced shock. In the present study we examined the LPS-induced response in IRAK-4 KD mice in more detail. We show that IRAK-4 kinase activity is required for certain aspects of TLR-mediated signaling but not for others. We found that IRAK-4 KD cells displayed reduced JNK and p38 signaling, while NF-kappaB was activated to a normal level but with delayed kinetics compared to wild-type cells. TLR4-mediated IRF3 activation was intact in these cells. Comprehensive analysis of expression of LPS-inducible genes by microarray demonstrated that IRAK-4 KD cells were severely impaired in the expression of many pro-inflammatory genes, suggesting their dependence on IRAK-4 kinase activity. In contrast, the expression of a subset of LPS-induced genes of anti-viral response was not affected by IRAK-4 kinase deficiency. Additionally, we demonstrate that LPS-activated early expression and production of some cytokines, e.g., TNF-alpha, is partially induced in the absence of IRAK-4 kinase activity. This suggests that the partially unaffected TLR4-mediated signaling could still drive expression of these genes in early phases and that IRAK-4 kinase activity is important for a more sustained anti-bacterial response.     

碳化硅对成骨细胞增殖和分化的影响

目的研究碳化硅(SiC)的体外生物相容性,为探索SiC作为骨缺损修复材料的可行性奠定基础。方法实验组为实质SiC,对照组为致密羟基磷灰石(HA)。将取自大鼠胎鼠颅骨的成骨细胞分别接种于2组材料表面。分别采用扫描电子显微镜、四甲基偶氮唑盐(MTT)法、碱性磷酸酶(ALP)含量测定技术、流式细胞仪检测细胞周期,观察分析两种材料表面上的细胞的增殖和分化能力。结果扫描电子显微镜显示:原代成骨细胞在两种材料表面伸展良好,细胞在材料表面伸出很多伪足,并且在材料表面可见明显的细胞外基质沉积。两组材料上细胞的MTT值从1、3、5、7 d随观察时间逐渐升高,并且各个时间点实质SiC均高于致密HA,两者之间的差异有统计学意义(P<0.05)。两组材料上细胞的ALP含量从1、3、5、7 d随观察时间逐渐升高;在1、3 d时,致密HA高于实质SiC,在5、7 d时,致密HA低于实质SiC,但是两组之间的差异均无统计学意义(P>0.05)。1、3、5 d两组材料的细胞增值指数(PI)值逐渐升高,高峰出现在第5天,第7天时下降,两组材料在各个时间点的PI均接近,差异无统计学意义(P>0.05)。结论实质SiC具有与致密HA相似的良好的细胞相容性。     

不同浓度地塞米松体外对人成骨细胞和破骨细胞分化的影响

目的: 探讨地塞米松(DEX)体外对人成骨细胞(OBs)和破骨细胞(OCs)分化的影响。方法: 以DEX为主要成分的诱导剂体外刺激正常人骨髓间充质干细胞(MSCs),茜素红染色及碱性磷酸酶(ALP)定量法检测OBs间钙结节形成及OBs中ALP水平;改变DEX浓度后,再检测ALP水平以及用Western blotting检测OBs中磷酸化GSK-3β蛋白的表达;外源性核因子κB受体活化因子配基(RANKL)刺激人骨髓单个核细胞(BMMs)14 d后,用抗酒石酸酸性磷酸酶染色鉴定OCs形成情况、Western blotting检测BMMs中RANKL下游的信号途径;不同浓度DEX刺激MSCs 7 d后,用ELISA和Western blotting检测培养液中可溶性RANKL(sRANKL)水平及MSCs中RANKL蛋白表达。结果: 含0.1 μmol/L DEX的诱导剂刺激MSCs后可有钙结节形成,在DEX 0.001-0.1 μmol/L浓度范围内,OBs中ALP水平逐渐增高、磷酸化GSK-3β蛋白表达逐渐增强,当DEX浓度进一步增加后(0.1-10 μmol/L), ALP水平和磷酸化GSK-3β蛋白表达反而下降;外源性RANKL可以诱导BMMs分化为OCs,且BMMs中磷酸化IκBα、SPAK/JNK、p38 MAPK、p44/42 MAPK表达增强;在0.001-10 μmol/L浓度范围内,DEX刺激MSCs后,培养液中 sRANKL水平和MSCs中RANKL蛋白表达逐渐增高,且sRANKL水平和DEX浓度呈正相关(r=0.821,P<0.05)。结论: 在低浓度(0.001-0.1 μmol/L)范围内,DEX既促进OBs分化,又可促进OCs分化。在高浓度(0.1-10 μmol/L)范围内,仍能促进OCs分化,但失去了其对OBs的分化作用。     

Effects of IL-1 Receptor-Associated Kinase-4 Gene Silencing on Human Osteoblast-Like Cells

The aim of this study is to identify the effects of interleukin-1 receptor-associated kinase-4 (IRAK-4) gene silencing on human osteoblast-like cells. The siRNA sequences of the target gene, IRAK-4, were constructed and transferred into MG63 cells (control group = MG63 cells; SC group = MG63 cells transfected with scrambled IRAK-4 siRNA; KD group = MG63 cells transfected with 75 nM IRAK-4 siRNA). The morphological changes, cell growth, cell-cycle progression, apoptosis, and the expression of various cytokines and proteins were compared. Compared with the control and SC groups, IRAK-4 gene silencing in MG63 cells caused morphological changes, inhibited growth, altered the cell-cycle distribution, increased apoptosis (p < 0.05), decreased bone alkaline phosphatase and osteocalcin levels (p < 0.05), and decreased protein expression of Bcl-2/Bax and Bcl-2, p-JNK1/2, p-ERK1/2, and p-p38MAPK (p < 0.05). The results indicated that IRAK-4 gene silencing in MG63 cells inhibited cell proliferation and function and increase apoptosis, which may be related to the decreased Bcl-2/Bax ratio and inhibition of the protein expression of various components of the mitogen-activated protein kinase pathways. The results of this study may help improve the understanding of the relationship between IRAK-4 and osteoblast-like cells and the interactions between various cytokines in the periprosthetic inflammatory environment.     

阻断经典Wnt通路对棕色脂肪干细胞向起搏样细胞分化的作用

目的:研究阻断经典Wnt通路对棕色脂肪干细胞向起搏样细胞分化的影响。方法:在诱导棕色脂肪干细胞向起搏特性诱导的过程中,培养基中加入经典Wnt通路阻断剂Dkk-1培养10 d。相差显微镜观察诱导组细胞的形态学变化、应用real-time PCR检测其中起搏细胞发育相关结构基因的表达情况,免疫荧光显色普通光镜和激光共聚焦显微镜观察起搏特征分子的蛋白表达。结果:分化后的棕色脂肪干细胞具有起搏细胞特性,经Dkk-1诱导后,棕色脂肪干细胞向起搏样细胞的转化率明显提高,起搏细胞发育相关基因和蛋白表达明显上调。结论:阻断经典Wnt通路可促进棕色脂肪干细胞向起搏样细胞的分化。     

野黄芩苷体外促成骨分化作用研究

目的研究野黄芩苷的体外促成骨分化作用。方法利用荧光素酶报告基因系统检测野黄芩苷对稳定转染bmp2启动子的MC3T3-bmp2-Luc细胞中bmp2转录活性的影响;体外培养小鼠颅骨来源的前体成骨细胞系MC3T3-E1和小鼠多能间充质干细胞样成纤维细胞C3H10T1/2,采用MTT的方法检测野黄芩苷对细胞增殖的影响;p-NPP法检测野黄芩苷对成骨细胞内碱性磷酸酶活性的影响以及通过茜素红染色的方法考察野黄芩苷对钙化结节形成的影响;Real-time PCR进一步验证野黄芩苷长时间诱导后对成骨细胞bmp2 m RNA水平的影响。结果野黄芩苷可以在20μmol/L显著上调bmp2转录活性(P0.001);在1~20μmol/L的剂量浓度范围内,野黄芩苷作用72 h后对MC3T3-E1细胞增殖不明显但也无杀伤作用。野黄芩苷在两种实验用细胞中均能剂量依赖地上调ALP的活性,其中10μmol/L和20μmol/L最为显著(P0.05),并且在C3H10T1/2细胞中该作用呈时间依赖性。同时也观察到24 d诱导后,野黄芩苷(5~10μmol/L)可以增加成骨细胞钙化结节的数目,且诱导12 d后,在5~20μmol/L浓度下上调bmp2 m RNA的水平。结论野黄芩苷具有体外促成骨分化的活性,有潜力成为抗骨质疏松候选化合物。