体外诱导C2C12细胞向成骨细胞的分化

目的成骨细胞特异性转录因子a1(core binding factor a1,Cbfa1)通过调节生长因子和骨特异性细胞外基质蛋白的基因表达而参与成骨细胞的分化和骨发育过程。文中构建成Cbfa1,以腺病毒载体转染成肌细胞C2C12,为种子细胞构建组织工程化骨。方法体外培养小鼠成肌细胞C2C12,用重组腺病毒质粒pAd-IL-31介导Cbfa1/Osf2基因瞬时转染小鼠成肌C2C12细胞,Western blot检测Cbfa1蛋白表达。结果 Cbfa1蛋白表达、碱性磷酸酶(alkaline phosphatase,ALP)活性测定、骨钙素(osteocalcin,OCN)分泌量以及茜素红染色感染组明显高于对照组。结论成肌细胞C2C12可以作为种子细胞构建组织工程化骨。     

LncRNA AK051397在BMP-2诱导的C2C12成骨分化中的作用

目的研究骨形态发生蛋白2（bone morphogenetic protein-2,BMP-2）诱导后表达上调的LncRNA AK051397在C2C12成骨分化过程中的作用。方法 BMP-2诱导C2C12成骨分化过程,实时定量PCR技术与碱性磷酸酶（ALP）染色检测成骨相关指标。对C2C12细胞在BMP-2诱导下,成骨分化过程中的LncRNAs表达变化进行芯片分析（ArrayStar LncRNA Array）,筛选出表达明显上调的LncRNAs,最后采用siRNA干扰的方法下调LncRNAs表达后分析其对成骨分化过程的影响。结果 BMP-2诱导C2C12成骨分化过程中,成骨指标ALP、SPT增高,成肌指标MYOG降低。芯片结果表明,LncRNA AK051397在BMP2诱导后表达明显上调,处理组与未处理组相比升高4.9倍（P〈0.05）。干扰AK051397后成骨分化指标ALP、SP7表达下降,MYOG表达上升。结论 LncRNA AK051397在C2C12细胞中具有促进成骨分化的作用,同时也具有抑制细胞成肌分化的作用。     

MSCs成骨分化中BMP2对成骨转录因子SATB2表达的调控作用

目的探索间充质干细胞（MSCs）成骨分化中骨形态发生蛋白2（BMP2）对成骨转录因子SATB2表达的调控作用。方法体外培养小鼠间充质细胞系C2C12,腺病毒介导的BMP2（Adv-BMP2）诱导其向成骨细胞分化,建立并验证C2C12细胞成骨分化细胞模型。Real-Time PCR和Western blotting分别检测C2C12细胞成骨分化过程中经不同浓度Adv-BMP2处理不同时间时SATB2 mRNA和SATB2蛋白表达;以经相应浓度Adv-β-Gal处理细胞作对照。结果经150 pfu/cell Adv-BMP2处理C2C12细胞5 d后,成骨细胞标志基因Ⅰ型胶原、骨唾液酸蛋白和骨钙素表达以及碱性磷酸酶活性均显著增加,MSCs成骨分化模型构建成功。150 pfu/cell Adv-BMP2诱导C2C12细胞成骨分化过程中,SATB2 mRNA和SATB蛋白表达随分化进程而增加;Adv-BMP2浓度为0～225 pfu/cell时,SATB2表达随Adv-BMP2浓度升高而增加。结论 BMP2可调控SATB2的表达,从而影响MSCs成骨分化。     

白藜芦醇对C3H10T1/2间质干细胞成骨分化及CXCL12、EGFR和CCL2基因表达的影响

目的 探讨白藜芦醇对C3H10T1/2细胞成骨分化的作用及CXCL12、EGFR和CCL2基因表达的影响。方法采用CCK-8法检测不同浓度白藜芦醇对C3H10T1/2细胞增殖影响,碱性磷酸酶染色鉴定早期成骨分化,实时荧光定量PCR法检测CXCL12、EGFR和CCL2基因的表达。结果 白藜芦醇在20μmol/L浓度对C3H10T1/2细胞增殖没有影响(P>0.05),随着浓度增加,40、80、100μmol/L的白藜芦醇明显抑制细胞增殖(P<0.05)。20μmol/L白藜芦醇能增强重组人骨形成蛋白2(rhBMP-2)诱导C3H10T1/2的碱性磷酸酶染色。白藜芦醇对C3H10T1/2细胞CXCL12、EGFR、CCL2基因表达没有明显影响(P>0.05)。结论 白藜芦醇能促进rhBMP-2诱导成骨分化。促成骨分化作用可能不是通过调控CXCL12、EGFR和CCL2基因的表达来实现。     

pSG5-Cbfa1转染兔皮肤成纤维细胞及其瞬时表达

目的　探讨外源性小鼠Cbfa1基因在兔皮肤成纤维细胞中获得瞬时表达的可行性。方法　在阳离子脂质体介导下 ,将含外源性小鼠Cbfa1基因的 pSG5 Cbfa1真核表达质粒导入原代培养的第 2代兔皮肤成纤维细胞内。采用RT PCR及Western Blot法检测Cbfa1基因在兔皮肤成纤维细胞内的瞬时表达。同时采用RT PCR法检测细胞内骨钙素及碱性磷酸酶基因的表达情况。结果　转染pSG5 Cbfa1真核表达质粒的兔皮肤成纤维细胞内有大量小鼠Cbfa1mRNA转录及蛋白瞬时表达 ,同时诱导骨钙素mRNA及碱性磷酸酶mRNA大量表达。结论　在阳离子脂质体介导下 ,小鼠Cbfa1基因能够导入兔皮肤成纤维细胞内并获得瞬时表达 ,同时诱导细胞内成骨特异性骨钙素基因及碱性磷酸酶基因的转录     

pSG5-Cbfal转染兔皮肤成纤维细胞及其瞬时表达

目的 探讨外源性小鼠Cbfal基因在兔皮肤成纤维细胞中获得瞬时表达的可行性。方法 在阳离子脂质体介导下，将含外源性小鼠Cbfal基因的pSG5-Cbfal真核表达质粒导入原代培养的第2代兔皮肤成纤维细胞内。采用RT-PCR及Western-Blot法检测Cbfal基因在兔皮肤成纤维细胞内的瞬时表达。同时采用RT—PCR法检测细胞内骨钙素及碱性磷酸酶基因的表达情况。结果 转染pSG5-Cbfal真核表达质粒的兔皮肤成纤维细胞内有大量小鼠Cbfal mRNA转录及蛋白瞬时表达，同时诱导骨钙素mRNA及碱性磷酸酶mRNA大量表达。结论 在阳离子脂质体介导下，小鼠Cbfal基因能够导入兔皮肤成纤维细胞内并获得瞬时表达，同时诱导细胞内成骨特异性骨钙素基因及碱性磷酸酶基因的转录。     

BICC1对骨髓基质细胞定向分化的调控作用研究

目的:探讨BICC1在骨髓基质细胞向成骨细胞及脂肪细胞分化过程中的作用。方法:构建Bicc1过表达质粒Bicc1-pcDNA3.1,以pcDNA3.1为对照,分别转染小鼠骨髓基质细胞ST2。对两组细胞进行成脂和成骨诱导,在成骨诱导14 d时碱性磷酸酶染色检测成骨分化情况,在成脂诱导5 d时利用油红O染色检测脂滴形成情况;采用qRT-PCR及Western blot技术检测细胞Bicc1过表达对成骨及成脂相关因子的影响。结果:酶切及测序结果显示Bicc1过表达质粒构建成功,将其转染到ST2细胞后,Bicc1 mRNA表达水平较对照组升高15.23倍（P＜0.05）。成骨诱导条件下,Bicc1过表达组ST2细胞碱性磷酸酶染色增强,成骨相关因子Osterix、碱性磷酸酶、Osteopontin、Runt相关转录因子2（Runx2）和骨钙素的mRNA和/或蛋白表达水平显著上升（均P＜0.05）。成脂诱导条件下, Bicc1过表达组ST2细胞中脂滴形成减少,油红OD520较对照组明显降低（P＜0.01）,成脂相关因子过氧化物酶体增殖物活化受体γ（PPARγ）、CCAAT增强子结合蛋白α（C/EBPα）、脂肪酸结合蛋白（FABP4/aP2）和adipsin的mRNA及蛋白表达水平显著下降（均P＜0.05）。结论:BICC1可促进骨髓基质细胞向成骨细胞分化,抑制其向脂肪细胞分化。     

rhBMP-2在诱导C3H10T1/2干细胞成骨中对MMP-13、Collagen-2 mRNA表达的影响

目的研究基质金属蛋白酶13(MMP13)、II型胶原(collagen2)在C3H10T1/2细胞中的相互关系,探讨rhBMP-2在诱导C3H10T1/2成骨的同时对MMP13以及Collagen2 mRNA表达水平的影响。方法取C3H10T1/2细胞加入rhBMP-2诱导成骨细胞的产生,Von Kossa染色观察细胞形态,同时在不同时间段抽取总RNA,利用Real-time PCR检测MMP13、Collagen2的表达情况。结果未加rhBMP-2的细胞中MMP13、Collagen2前10d表达呈负相关;而rhBMP-2处理后的细胞中MMP-13表达水平受抑制,且MMP13和collagen2前14d表达呈明显负相关。结论MMP-13和Collagen-2 mRNA表达水平具明显相关性,rhBMP-2在诱导成骨的同时,具有抑制MMP-13表达的作用。     

基因沉默组织型转谷氨酰胺酶抑制SaOS-2细胞成骨分化

目的 研究组织型转谷氨酰胺酶（tissue transglutaminase, TG2）是否参与人SaOS-2细胞系成骨分化过程。方法 使用携带短发夹RNA（short hairpin RNA, shRNA）的慢病毒转染SaOS-2细胞以敲减TG2表达，以SaOS-2细胞及转染了含阴性对照shRNA病毒的SaOS-2作为对照组，分别进行体外成骨诱导培养，并进行以下检测：1）诱导14 d后各组矿化情况（茜素红染色），2）诱导4 d、7 d后碱性磷酸酶活性及I型胶原、骨钙素、骨形态发生蛋白-2（BMP-2）的mRNA表达，并与诱导前的表达水平相比较。结果 SaOS-2细胞组及转染阴性对照shRNA组在体外成骨诱导过程中I型胶原、骨钙素、BMP-2的mRNA表达和ALP活性逐渐增加，14 d时形成明显矿化结节，而TG2敲减后的SaOS-2细胞在诱导14 d时矿化水平显著低于对照组，诱导7 d时ALP活性及I型胶原、骨钙素、BMP-2的mRNA表达水平显著低于对照组。结论 组织型转谷氨酰胺酶参与SaOS-2细胞体外成骨分化及矿化。     

利用CRISPR/Cas9系统构建Lrtm1基因敲除的C2C12细胞系

目的：利用CRISPR/Cas9技术构建稳定敲除Lrtm1（leucine-rich repeats and transmenbrane domains 1）基因的C2C12细胞系,为研究Lrtm1基因的作用提供实验基础。方法：设计3对针对Lrtm1基因的向导RNA（sgRNA）,将sgRNA插入载体pCRISPR-LvSG06中;利用慢病毒包装系统包装含有sgRNA的重组质粒pCRISPR-LvSG06;将病毒感染C2C12细胞,并加入嘌呤霉素筛选,将筛选嘌呤霉素阳性的细胞提取RNA,逆转录成cDNA;设计Cas9引物,利用cDNA为模版,PCR验证C2C12细胞中Cas9的表达,确认慢病毒成功感染C2C12细胞;利用96孔板挑选单克隆细胞的方法筛选得到单克隆细胞;将扩增的单克隆细胞提取基因组DNA,测序Lrtm1基因相关序列并与野生型Lrtm1基因进行对比,确认敲除成功的克隆细胞株;诱导敲除Lrtm1稳定细胞株成肌分化,检测成肌分化标志因子Myosin的蛋白表达,RT-PCR检测转录因子PAX7的mRNA表达,Western blot检测H3K27me3蛋白水平。结果：测序结果显示向导RNA（sgRNA）成功插入载体质粒;将单克隆细胞DNA测序结果显示A和C克隆成功敲除Lrtm1基因;敲除Lrtm1基因后成肌分化标志因子Myosin蛋白表达降低,成肌转录因子PAX7 mRNA的表达降低,在分化72和96 h组,H3K27me3蛋白水平较野生型组增高。结论：利用CRISPR/Cas9技术成功敲除Lrtm1基因,稳定敲除Lrtm1基因的C2C12细胞系构建成功;敲除Lrtm1后能抑制C2C12细胞成肌分化,并且抑制成肌转录因子PAX7的mRNA表达,PAX7 mRNA表达降低的原因可能为H3K27me3水平增高。     

Effect of rhBMP-2 and Osteogenic Revulsants on Proliferation and Differentiation of Bone Marrow Stromal Cells in Rats

The effects of recombinant human bone morphogenetic protein-2 （rhBMP-2） and osteogenic revulsants alone or in combination at different time points and in different dosages on proliferation and osteogenesis of bone marrow stromal cells （BMSCs） in SD rats were investigated. Rat BMSCs were cultured in vitro and induced by rhBMP-2 in different dosages （10, 50, 100 and 200μg/L） alone or in combination with osteogenic revulsants. MTT colorimetric assay was used to evaluate The proliferation, activity of alkaline phosphoric （ALP） and osteocalcin were measured at 3rd, 6th, 9th, 12th day respectively. The results showed that rhBMP-2 and osteogenic revulsants could promote the differentiation of BMSCs towards osteoblast phenotype. The proliferation of BMSCs could be enhanced by rhBMP-2 in a dose-dependent manner. The expression of osteoblast phenotype was significantly higher by using both of them than by using them alone, which was verified by the activity of ALP and osteocalcin. It was suggested that the combined use of rhBMP-2 and osteogenic revulsants could promote the proliferation and simultaneously induce and maintain the expression of osteoblast phenotype of BMSCs in rats.     

重组人骨形成蛋白-2在诱导C3H10T1/2干细胞成骨中对MMP-9 mRNA表达的影响

目的：测定MMP-9mRNA在C3H10T1／2 clone 8(10T1／2)中的表达，探讨rhBMP-2诱导10T1／2产生成骨细胞时对MMP-9mRNA表达的影响。方法：取10T1／2培养至细胞完全贴壁，加入rhBMP-2培养28天，同时利用Real—time PCR检测MMP-9在10T1／2中不同时间段的表达。结果：10T1／2经rhBMP-2的诱导14天出现钙化点，MMP-9mRNA也随着rhBMP-2的加入表达降低，而对照组几乎不变化。结论：rhBMP-2在诱导10T1／2产生成骨细胞的同时抑制着MMP-9mRNA的表达。     

重组人 BMP-2 诱导 C3H10T1/2 间质干细胞定向成骨分化早期基因表达谱分析简

目的 研究间质干细胞早期定向成骨分化基因表达谱,为研究基因对早期成骨定向分化调控机制提供实验基础.方法 分别提取重组人骨形成蛋白2（rhBMP-2）诱导组和对照组C3H10T1/2细胞总RNA,进行扩增标记后,与ArraySTAR小鼠基因芯片杂交,应用生物信息学软件GeneSpring和GATHER对基因芯片数据进行分析.应用STRING在线软件对差异表达基因构建蛋白互作网络并进行网络分析.结果 C3H10T1/2早期成骨分化中,主要富集发育、器官形成等分子功能本体以及细胞因子-细胞因子受体作用信号通路.成骨分化1d和4d均上调表达基因42个,下调表达基因45个.网络分析研究表明：Egfr、Cxcl 12等信号分子参与调控rhBMP-2诱导成骨分化.结论 筛选的差异表达基因和信号分子对早期成骨分化调控具有重要作用,为进一步全面解析早期成骨定向分化提供实验基础.     

Pericyst may be a new pharmacological and therapeutic target for hydatid disease

Background  Most hydatid cysts with calcified walls are biologically and clinically silent and inactive. Transforming growth factor-beta 1 (TGF-β1) plays a critical role in the calcification process of cells. The aim of this study was to assess the effect of modulating TGF-β1 signaling on the calcification of hydatid cysts.

Methods  Pericyst cells isolated from hepatic hydatid cysts were cultured with osteogenic media. These cells were assessed for alkaline phosphatase activity and mineralization capacity using Alizarin Red staining. Cells were also treated with recombinant human TGF-β1 and TGF-β inhibitor, and the expression profiles of osteoblast markers (RUNX2, osterix, and osteocalcin) were analyzed using Western blotting. The effects of inhibiting TGF-β1 signaling on calcification of pericyst walls were assessed using different doses of TGF-β inhibitor for 7 weeks in a preclinical disease model of liver cystic echinococcosis.

Results  Cells within the pericyst displayed high levels of alkaline phosphatase activity and mineralized nodule formation, as induced by osteogenic media. These activities, as well as expression profiles of osteoblast markers (RUNX2, osterix, and osteocalcin) could be inhibited by addition of recombinant human TGF-β1 (rhTGF-β1) and enhanced by TGF-β inhibitor. In the animal model of cystic echinococcosis, inhibition of TGF-β1 signaling increased calcification of the pericyst wall, which was associated with decreased cyst load index and lower viability of protoscoleces.

Conclusions  Cells within the pericysts adopt an osteoblast-like phenotype and have osteogenic potential. Inhibition of TGF-β1 signaling increases hydatid cyst calcification. Pharmacological modulation of calcification in pericysts may be a new therapeutic target in the treatment of hydatid disease.

     

Hypoxia-induced MTA1 promotes MC3T3 osteoblast growth but suppresses MC3T3 osteoblast differentiation

Background

Bone fracture is one of the most common physical injuries in which gene expression and the microenvironment are reprogramed to facilitate the recovery process.

Methods

By specific siRNA transfection and MTT assay, we evaluated the effects of metastasis-associated gene 1 (MTA1) in osteoblast growth. To show the role of MTA1 in osteoblast under hypoxia conditions, by overexpressing and silencing MTA1 expression, we performed mineral deposition and alkaline phosphatase activity assay to observe the differentiation status of osteoblast cells. Real-time PCR and Western blot assays were adopted to detect the expression of certain target genes.

Results

Here, we reported that hypoxia-induced MTA1 expression through hypoxia-induced factor 1 alpha (HIF-1α) and stimulated the growth of osteoblast MC3T3 cells. Silencing of MTA1 through specific siRNA suppressed MC3T3 cell growth and elicited cell differentiation and induced alkaline phosphatase activation and the upregulation of bone morphogenetic protein-2 and osteocalcin.

Conclusions

We found that MTA1 was regulated by HIF-1α in hypoxia circumstance to suppress osteoblast differentiation. These findings provide new insights for bone fracture healing and new strategies to develop potential targets to promote fracture healing.

Electronic supplementary material

The online version of this article (doi:10.1186/s40001-015-0084-x) contains supplementary material, which is available to authorized users.     

Effects of secretive bone morphogenetic protein 2 induced by gene transfection on the biological changes of NIH3T3 cells

Background Bone morphogenetic proteins (BMPs), which belong to the transforming growth factor beta superfamily, are powerful regulators of cartilage and bone formation. This study investigated the biological changes of NIH3T3 cells incubated with secretive BMP2 that was induced by gene transfection through transwell. Methods Eukaryonic expression vector (pcDNA3.1-B2) was transfered into NIH3T3 cells with Sofast&#8482;,a positive compound transfection agent. The positive cell clones were selected with G418. The cytoplasmic and extracellular expressions of BMP2 were determined by immunohistochemical stain and enzyme-linked immunosorbent assay. NIH3T3 cells were co-cultured with hBMP2 gene transfecting cells through transwell, and the ultrastructure, alkaline phosphatase activity and the expression of osteocalcin (the marker of osteogenetic differentiation) changes were observed. Results There were cytoplasmic and extracellular expressions of BMP2 in transfecting NIH3T3 cells. The ultrastructural changes, the high activity of alkaline phosphatase and the positive stain of osteocalcin suggested the osteogenetic differentiation tendency of NIH3T3 cells co-cultured with transfecting NIH3T3 cells. Conclusion Secretive BMP2 that is induced by gene transfection could promote the osteogenetic differentiation of fibroblast cells.     

USF2与其截短体真核表达载体的构建及对Smurf1/2转录水平的影响

目的 构建上游刺激因子2(USF2)及其截短体的真核表达载体,鉴定USF2蛋白中抑制泛素连接酶Smurf1/2转录的功能区域。方法 采用PCR技术扩增USF2 及其两个截短体USF2(1~235aa)、USF2(236~346aa)编码基因,分别将其构建在pCMV-Myc重组载体上,转染真核细胞后验证其表达,Western blot及实时定量PCR确定USF2下调Smurf1/2转录水平的区域。结果 成功地将USF2及其两个截短体编码基因构建至pCMV-Myc载体,并验证其在真核细胞中的正确表达,Western Blot和实时定量PCR实验结果显示,USF2 C端236~346aa区域对Smurf1/2的转录水平有抑制效应。结论 USF2通过其C端236~346aa区域对Smurf1/2的转录产生抑制效应。     

微囊化成骨细胞诱导骨髓间充质干细胞体外成骨分化的量效研究

目的探讨微囊化成骨细胞体系细胞添加量对诱导骨髓间充质干细胞体外成骨分化的影响。方法制备含有成骨细胞的海藻酸钠-聚赖氨酸-海藻酸钠微囊,与间充质干细胞的共培养,在1,7,14 d通过细胞增殖量、碱性磷酸酶活性、实时定量PCR等检测,统计结果并分析。结果各时段细胞增量无统计学意义;碱性磷酸酶活性随细胞浓度增加表现出递增趋势,且骨钙蛋白mRNA的表达结果基本一致。结论微囊化成骨细胞在低浓度下已能促进骨髓间充质干细胞成骨分化,浓度升高时促分化能力越强,但达到一定浓度后继续提高时,对成骨分化的作用则不再增强。