Overexpression of microRNA-124 promotes the neuronal differentiation of bone marrow-derived mesenchymal stem cells

microRNAs(miRNAs) play an important regulatory role in the self-renewal and differentiation of stem cells. In this study, we examined the effects of miRNA-124(miR-124) overexpression in bone marrow-derived mesenchymal stem cells. In particular, we focused on the effect of overexpression on the differentiation of bone marrow-derived mesenchymal stem cells into neurons. First, we used GeneChip technology to analyze the expression of miRNAs in bone marrow-derived mesenchymal stem cells, neural stem cells and neurons. miR-124 expression was substantially reduced in bone marrow-derived mesenchymal stem cells compared with the other cell types. We constructed a lentiviral vector overexpressing miR-124 and transfected it into bone marrow-derived mesenchymal stem cells. Intracellular expression levels of the neuronal early markers β-III tubulin and microtubule-associated protein-2 were significantly increased, and apoptosis induced by oxygen and glucose deprivation was reduced in transfected cells. After miR-124-transfected bone marrow-derived mesenchymal stem cells were transplanted into the injured rat spinal cord, a large number of cells positive for the neuronal marker neurofilament-200 were observed in the transplanted region. The Basso-Beattie-Bresnahan locomotion scores showed that the motor function of the hind limb of rats with spinal cord injury was substantially improved. These results suggest that miR-124 plays an important role in the differentiation of bone marrow-derived mesenchymal stem cells into neurons. Our findings should facilitate the development of novel strategies for enhancing the therapeutic efficacy of bone marrow-derived mesenchymal stem cell transplantation for spinal cord injury.     

The Effects of Osterix on the Proliferation and Odontoblastic Differentiation of Human Dental Papilla Cells

Introduction

Dental papilla cells (DPCs) are precursors of odontoblasts and have the potential to differentiate into odontoblasts. Osteoblasts and odontoblasts have many common characteristics. Osterix (Osx) is essential for osteoblast differentiation. However, no information is available for the effects of Osx on the odontoblastic differentiation of DPCs. The purpose of this study was to investigate the effects of Osx on the proliferation and odontoblastic differentiation of DPCs.

Methods

An immortalized human dental papilla cell (hDPC) line was used. Osx was stably overexpressed or knocked down in hDPCs with infection of lentiviral particles to determine its biological effects on hDPCs. The proliferation of cells was measured by the 5-ethynyl-2′-deoxyuridine incorporation assay and direct cell counting. Expressions of dentin sialophosphoprotein, nestin, dentin matrix protein 1, and alkaline phosphatase were detected by real-time polymerase chain reaction to determine the odontoblastic differentiation of cells. The mineralization ability of cells was evaluated by von Kossa staining and alkaline phosphatase activity assay.

Results

Overexpression of Osx retarded the proliferation of hDPCs, whereas knockdown of Osx increased the cell proliferation. Overexpression of Osx promoted the odontoblastic differentiation of hDPCs by up-regulating odontoblastic differentiation genes and increased the mineralization ability of hDPCs. Knockdown of Osx down-regulated odontoblastic differentiation genes and decreased the mineralization ability of hDPCs.

Conclusions

Osx might function as a potential regulator for the proliferation and odontoblastic differentiation of hDPCs.     

慢病毒携带shRNA对宫颈癌细胞中HPV16型E6表达的抑制作用

目的研究慢病毒携带的短发夹状干扰RNA(short hairpin RNA, shRNA)对宫颈癌Caski细胞中人乳头瘤病毒(human papilloma virus, HPV)16型E6表达的抑制作用.方法将靶向HPV16型E6的shRNA表达序列克隆到改建的慢病毒表达载体PLL3.7中,经限制性酶切鉴定和测序后,与3种包装质粒混合,以Lipofectamine 2000包裹后转染293FT细胞,72 h后收取含病毒的上清液并感染宫颈癌Caski细胞,感染48 h后加入G418筛选阳性克隆.每天对阳性细胞克隆进行细胞计数;提取细胞总mRNA,进行RT-PCR反应.结果与对照组相比HPV16型E6的表达降低70%,宫颈癌Caski细胞生长速度减慢50%.结论慢病毒携带的短发夹状干扰RNA能干扰宫颈癌细胞中HPV16型E6的表达并有抑制癌细胞生长的作用.     

HSP90β干扰和过表达慢病毒载体的构建及其在骨肉瘤细胞Saos-2中的表达

目的:获得热休克蛋白90β(HSP90β)基因干扰和过表达慢病毒表达系统,并检测其在人骨肉瘤细胞株Saos-2中的表达水平。方法:设计合成shRNA,以慢病毒表达质粒构建HSP90β干扰和过表达载体,酶切电泳、测序技术鉴定载体构建是否成功。重组病毒转染H1299细胞,以嘌呤霉素筛选稳定转染的Saos-2细胞,通过荧光显微镜观察计数获得转染效率。将感染好的细胞分为干扰NC组（NEG-shRNA）、干扰组（shRNA-HSP90β）、过表达NC对照组（NEG-pEZ）及过表达组（pEZ-HSP90β）。通过qRT-PCR 与Western blotting 分别从mRNA 和蛋白表达水平验证目的基因的干扰和过表达水平。结果:插入慢病毒表达载体的基因片段与目的基因的碱基序列完全一致。病毒包装成功后,嘌呤霉素最小致死浓度1 μg/ml,感染复数200,感染人Saos-2的感染效率达80%,其中shRNA-HSP90β组干扰效率为86.35%,pEZ-HSP90β组的mRNA相对表达量增加2.8倍。进一步研究发现,shRNA-HSP90β组较NEG-shRNA组中HSP90β蛋白表达明显降低,pEZ-HSP90β组较NEG-pEZ组HSP90β蛋白表达增加。结论:HSP90β基因干扰和过表达慢病毒载体构建成功,并能够在Saos-2中稳定表达。     

Construction of a lentiviral vector for RNA interference of human VIM gene and its silencing effect in pancreatic cancer cells

Objective： To construct a lentiviral expression vector for RNA interference （RNAi） of human VIM gene; and assess its gene silencing effect in pancreatic cancer cell line Panc-1. Methods： Three pairs of human VIM gene short hairpin RNA（shRNA） sequences were designed using a software available on-line and one pair came from document. After synthesis and annealing, four double-stranded oligonucleotides （dsOligo） were cloned into the pGCL-GFP/U6 plasmid, which were subsequently confirmed by polymerase chain reaction （PCR） and DNA sequencing analysis. Real-time PCR and Westemblotting were used to screen the effective pGCL-GFP-shRNA plasmid in 293T cells, then the most effective one was packed into the recombinant lentivirus Lv-VIM-shRNA with lentiviral packing materials pHelper 1.0 and pHelper 2.0 in 293T cells. The titer of lentivirus was determined by hole-by-dilution titer assay. The silencing effect of Lv-VIM-shRNA in Panc-1 calls were validated by real-time PCR and Western-blotting. Results： An effective Lv-VIM-shRNA was successfully constructed. The titer of lentivirus was determined on 2× 10^9TU/mL. The expressions of VIM mRNA and vimentin were down-regluated in the Panc-1 cells infected with Lv-VIM-shRNA. Conclusion： An effective Lv-VIM-shRNA could inhibit the expression of VIM gene in Panc-1 cells in vitro, which provides a tool for investigating the role of VIM gene in the signaling pathway involved in tumorigenesis and progression of pancreatic cancer and searching new therapeutic targets.     

沉默caspase-3基因影响骨髓间充质干细胞的增殖和凋亡

背景：缺血缺氧的心肌微环境导致植入的细胞存活率低。目的：观察沉默caspase-3基因对大鼠骨髓间充质干细胞增殖和体外缺血缺氧环境下凋亡的影响。方法：构建靶向caspase-3的shRNA重组慢病毒并转染骨髓间充质干细胞为转基因组,以正常细胞组和空载体组做对照,采用MTS法检测各组细胞增殖情况。建立缺血缺氧模型,real-timePCR和免疫组织化学分别检测缺血缺氧环境各组细胞的caspase-3mRNA和蛋白表达水平,应用流式细胞术检测不同缺血缺氧时间点（0,6,12,24,48h）各组细胞的凋亡率。结果与结论：重组慢病毒成功转染骨髓间充质干细胞,且细胞增殖活性升高（P〈0．05）。缺血缺氧环境下,转基因组细胞caspase-3在mRNA和蛋白表达水平相比对照组下降（P〈0．05）。沉默caspase-3能显著降低骨髓间充质干细胞的凋亡率（P〈0．05）,且随着缺血缺氧时间的延长凋亡率缓慢升高。结果提示,沉默caspase-3能加快骨髓间充质干细胞的生长速度和提高在体外缺血缺氧环境下的抗凋亡能力。     

人THAP11基因RNAi慢病毒表达系统的建立

目的构建人THAP11基因RNA干扰（RNAi）慢病毒载体,制备高滴度病毒颗粒,敲低K562细胞和脐带血CD34＋细胞中THAP11表达。方法采用第三代慢病毒包装系统,将含有特异性干涉THAP11的DNA序列克隆入穿梭质粒pSicoR中,构建siTHAP11-pSicoR质粒。在脂质体介导下,siTHAP11-pSicoR与包装质粒pLP1,pLP2,pLP/VSVG共转染HEK293T细胞,获得高滴度慢病毒颗粒。感染K562细胞,检测内源THAP11敲低效果。感染人CD34＋细胞,流式分选GFP阳性细胞,检测原代细胞中THAP11的敲低效果。结果成功构建针对THAP11两个位点的RNAi慢病毒载体siTHAP11-1和siTHAP11-2并获得慢病毒颗粒,病毒滴度检测可达1.8×108TU/ml。感染K562细胞后建立稳定株,THAP11的蛋白水平和mRNA水平均有下调。感染CD34＋细胞效率达30%以上,siT-HAP11-1可下调THAP11mRNA约80%,siTHAP11-2约下调85%。结论成功构建THAP11的RNAi慢病毒载体,包装后的病毒颗粒可有效敲低细胞株及原代细胞中内源性THAP11的表达,为后续研究THAP11对CD34＋细胞的影响奠定基础。     

In situ reprogramming to transdifferentiate fibroblasts into cardiomyocytes using adenoviral vectors: Implications for clinical myocardial regeneration

Objective

The reprogramming of cardiac fibroblasts into induced cardiomyocyte-like cells improves ventricular function in myocardial infarction models. Only integrating persistent expression vectors have thus far been used to induce reprogramming, potentially limiting its clinical applicability. We therefore tested the reprogramming potential of nonintegrating, acute expression adenoviral (Ad) vectors.

慢病毒携带shRNA抑制CR-1基因表达对 CNE-2细胞特性的影响

 【目的】 应用慢病毒介导的RNA干扰(RNAi)技术,有效沉默鼻咽癌细胞CNE-2的CR-1基因表达,研究CR-1对鼻咽癌细胞生物学行为的影响&;#65377; 【方法】 构建针对CR-1的siRNA慢病毒表达载体[含H1启动子和绿色荧光蛋白(GFP)]&;#65377;利用包装细胞293FT生产慢病毒,感染鼻咽癌细胞CNE-2, 流式筛选GFP阳性细胞&;#65377;应用荧光定量PCR&;#65380;Western blot检测病毒感染后CNE-2细胞中CR-1基因的mRNA和蛋白表达,获得干扰CR-1基因的细胞群&;#65377;并用MTT法&;#65380;平板克隆形成实验及Boyden侵袭小室观察CR-1干扰后对CNE-2细胞生物学行为的影响&;#65377; 【结果】 PCR 和测序证实,成功构建了CR-1 shRNA的慢病毒载体pLVTHM-shCR-1&;#65377;荧光定量PCR 和Western blot结果表明,所获得的细胞中CR-1 mRNA及蛋白表达水平较阴性对照组&;#65380;空白对照组均显著降低(P < 0.05)&;#65377;CR-1干扰后的细胞生长明显减慢,克隆形成能力减弱,侵袭运动能力下降&;#65377; 【结论】 通过RNAi技术阻断CR-1的表达,可抑制CNE-2细胞的生长&;#65380;增殖&;#65380;迁徙,提示CR-1在鼻咽癌的发生&;#65380;发展过程中起重要作用&;#65377;