小鼠胚胎成纤维细胞重编程为多能干细胞

背景：目前胚胎干细胞研究面临伦理争议及来源困难等诸多问题,人们一直在寻找不需破坏胚胎或卵细胞的建立多潜能干细胞的方法。 目的：构建小鼠诱导性多潜能干细胞系并对其进行鉴定。 方法：利用反转录病毒将3个干细胞基因Oct4、Sox2、Klf4导入小鼠胚胎成纤维细胞中,将其诱导为多潜能干细胞。通过镜下观察、碱性磷酸酶染色、反转录PCR(RT-PCR)、免疫荧光实验及畸胎瘤形成实验等对诱导性多潜能干细胞形态、多能性基因表达情况、干细胞表面标记及全能性等进行鉴定分析。 结果与结论：从小鼠胚胎成纤维细胞诱导而来的诱导性多潜能干细胞镜下观察呈典型的克隆状生长,圆形或椭圆形,与饲细胞分界清楚;RT-PCR、碱性磷酸酶染色及免疫荧光检测诱导性多潜能干细胞高表达胚胎干细胞相关基因及蛋白;种植在免疫缺陷鼠体内能够形成向内中外3个胚层分化的畸胎瘤,表明诱导性多潜能干细胞具有多潜能性。通过转导3种重编程因子可以将小鼠成纤维细胞诱导为类似胚胎干细胞的多潜能干细胞。     

人脐带间充质干细胞表达胚胎干细胞相关转录因子

背景：Nanog、Oct4和Sox2通过调节胚胎干细胞的基因转录,对其多潜能性和自我更新的能力具有关键性的调控作用,脐带间充质干细胞中这些胚胎干细胞相关转录因子的表达情况如何还不太清楚。 目的：研究脐带间充质干细胞中Nanog、Oct4和Sox2等这些胚胎干细胞相关转录因子的表达情况。 方法：胶原酶和胰酶消化法培养脐带间充质干细胞;mTeSRTM1体系进行无滋养层培养人胚胎干细胞,定量PCR比较上述两种细胞中Nanog、Oct4和Sox2 mRNA表达量的差异;免疫荧光检测上述两种细胞中Nanog、Oct4和Sox2的表达情况。 结果与结论：间充质干细胞表达胚胎干细胞标记Nanog、Oct4和Sox2,但Oct4主要表达在胞浆,且以Oct4B为主。脐带间充质干细胞Nanog、Oct4A和Sox2的表达量明显低于胚胎干细胞,其mRNA表达量分别为胚胎干细胞的20%,0.3%,10%左右。通过了解两种细胞Nanog、Oct4和Sox2的表达差异,可为优化脐带间充质干细胞重编程提供依据,也为进一步研究胚胎干细胞相关转录因子在成体干细胞表达起何种作用提供参考。     

巴马小型猪胎儿成纤维细胞重编程为诱导多能性细胞的研究

目的探讨巴马小型猪胎儿成纤维细胞重编程为诱导多能性细胞的方法。方法应用经典的逆转录病毒介导方法,将Oct4,Sox2,c-Myc和Klf4四种人源性转录因子转导入巴马小型猪的胎儿成纤维细胞中,建立形态和特征类似猪上胚层细胞来源的猪多能性细胞(pig induced pluripotent cells,piPCs)。免疫荧光化学方法检测多能性细胞标记物,RT-PCR检测了该细胞体外三胚层相关基因表达水平。结果巴马小型猪胎儿成纤维细胞重编程的piPCs细胞呈AKP染色阳性,体外长期传代都保持正常的染色体核型,猪上胚层多潜能性细胞标记分子Oct4,Sox2,Nanog,Tra-1-60,Tra-1-81和SSEA-4呈阳性表达,并且表达小鼠胚胎干细胞(ES)多潜能性细胞标记分子SSEA-1,体外诱导分化后具有三胚层特异基因的表达,但是体内分化能力存在缺陷。结论巴马小型猪胎儿成纤维细胞重编程成功诱导成多能性细胞。     

人参皂苷Rg1干预骨髓间充质干细胞转化为多潜能干细胞关键基因mRNA的表达

背景：将成体细胞重编程为诱导多潜能干细胞方案主要通过反转录病毒将Oct-4, Sox2, c-Myc, Klf4等基因转入成体细胞而实现。 目的：观察人参皂苷Rg1作用于骨髓间充质干细胞后,对成体细胞向诱导多潜能干细胞转化的关键性基因Oct4、Sox2、c-Myc、Klf4、Nanog mRNA表达的影响。 方法：培养骨髓间充质干细胞,对照组培养基为α-MEM,体积分数5%FBS,1%双抗;用药组培养基为α-MEM,体积分数15%FBS,1 000 U/mL Rat ESGRO®,1%双抗,并加入6.25 μmol/L和12.5 μmol/L人参皂苷Rg1。检测骨髓间充质干细胞Oct4,Sox2,c-Myc,Klf4,Nanog等mRNA的表达。 结果与结论：人参皂苷Rg1 6.25 μmol/L培养30 d,Nanog、c-Myc、Oct、Klf4、Sox2 mRNA表达均有升高,且Nanog、c-Myc与对照组差异有显著性意义。人参皂苷Rg1能促进骨髓间充质干细胞表达c-Myc,Nanog,但Nanog阳性的诱导多潜能干细胞在基因表达谱上很难与胚胎干细胞区分出来,提示人参皂苷Rg1对骨髓间充质干细胞向诱导多潜能干细胞转化可能具有促进作用。     

可利用小鼠诱导多能干细胞的建立及鉴定

目的 建立小鼠诱导多能性干细胞(iPSCs)模型,为干细胞和iPSCs研究提供可利用资源。 方法 取C57BL/6J小鼠12.5d的胚胎成纤维细胞,感染含有Sox2、Oct4、Klf4和c-Myc的慢病毒进行重编程。病毒感染后12d挑取iPSCs的克隆进行扩大培养,进行碱性磷酸酶染色鉴定。体外悬滴培养检测拟胚体（EB）的形成,并皮下接种BABL/c裸鼠检测畸胎瘤形成。全反式维甲酸诱导iPSCs克隆株定向分化。PCR法进行种属鉴定并检测支原体。 结果 得到了12个碱性磷酸酶阳性的小鼠iPSCs克隆株,体外可以形成拟胚体,其中9个克隆株可以在BALB/c裸鼠体内形成畸胎瘤。全反式维甲酸可诱导iPSCs定向分化为平滑肌细胞。iPSCs克隆株种属鉴定为鼠源性,无支原体的污染,细胞资源中心入库保藏。结论 成功建立了小鼠iPSCs模型,为干细胞、iPSCs重编程机制及定向分化研究提供可利用的资源。     

诱导多潜能干细胞

通过病毒载体导入4个外源转录因子Oct4、Sox2、c-Myc、Klf或者Oct4、Sox2、Nanog、Lin28入体细胞,可以诱导产生具有胚胎干细胞特性相似的诱导多潜能干细胞(induced pluripotent stem cells,iPS).iPS在疾病治疗和药物研究等领域具有非常重要的应用前景,但是目前存在诱导效率低以及致肿瘤性等缺点,采用改良方法诱导产生iPS是将来研究的重点.     

诱导性多潜能干细胞(iPS)的应用进展

<正>诱导性多潜能干细胞(induced pluripotent stem cells,iPS cells)自问世以来,取得了突飞猛进的发展。2006年8月,Takahashi和Yamanaka[1]确定诱导iPS细胞生成的4种转录因子是:Oct4、Sox2、c-Myc和Klf4。2007年11~     

过表达Sox2基因可增强人骨髓干细胞向神经元分化（英文）

目的:研究Sox2对于人骨髓间充质干细胞(hBMSCs)向神经元跨分化能力的影响。方法:利用Western Blot检测hBMSCs中Sox2、Oct4和c-Myc的表达,将携带Sox2和rhGFP编码序列的Tet-On慢病毒感染hBMSCs,通过多西环素(Dox)处理10 d诱导Sox2和rhGFP表达;利用神经诱导培养基诱导感染慢病毒的hBMSCs分化,通过免疫荧光染色技术检测神经元标记物Tuj1的表达;利用Western Blot技术检测Smad 2/3信号通路蛋白在hBMSCs向神经元分化过程中的表达水平。结果:Western Blot结果显示hBMSCs不仅表达Sox2和Oct4,同时还表达c-Myc;光镜下发现Sox2的过表达促进hBMSCs的形态向神经元样细胞转化,同时通过免疫荧光染色发现Tuj1的表达水平增加; Western Blot证实Sox2基因过表达引起hBMSCs中磷酸化Smad 2/3的表达水平降低。结论:Sox2可通过Smad 2/3信号通路增强人骨髓间充质干细胞向神经元分化。     

体细胞重编程为诱导多能干细胞

诱导多功能性干细胞(induced pluripotent stem cells,iPS细胞)是通过导入特定的转录因子(如Oct3/4、Sox2、c-Myc和Klf4等)将体细胞诱导重编程为多能性干细胞,其功能与胚胎干细胞相似.iPS细胞的建立,在生命科学领域引起了新的轰动.目前,iPS细胞的研究领域在转录因子的优化、iPS细胞的筛选、载体的运用、体细胞种类的选择和iPS细胞的应用等方面取得突破进展,但仍然存在致癌性、效率低等一系列急需解决的问题.     

应用双胎羊水多能干细胞建立诱导分化的内对照模型

目的 快速重编程羊水细胞为多能干细胞,建立诱导分化研究的内对照模型.方法 应用逆转录病毒介导4种基因(Oct4、Sox2、c-Myc、Klf4)诱导双胎羊水细胞,筛选羊水诱导性多能干细胞(human amniotic fluid-derived cells induced pluripotent stem cells,hAFDCs-iPSCs),对其进行多能性、体内外分化能力、核型等鉴定.结果 双胎hAFDC-iPSCs能维持自我更新状态,在蛋白和mRNA水平上高表达全能性的标志基因,具有体内外分化潜能,在体外长期培养能维持正常核型.结论 双胎hAFDCs-iPSCs遗传背景相一致,可以为iPSCs的诱导分化研究提供很好的内对照模型,并为胎儿的细胞自体移植治疗提供理想来源.     

Induced Pluripotent Stem Cells from Human Hair Follicle Mesenchymal Stem Cells

Reprogramming of somatic cells into inducible pluripotent stem cells (iPSCs) provides an alternative to using embryonic stem cells (ESCs). Mesenchymal stem cells derived from human hair follicles (hHF-MSCs) are easily accessible, reproducible by direct plucking of human hairs. Whether these hHF-MSCs can be reprogrammed has not been previously reported. Here we report the generation of iPSCs from hHF-MSCs obtained by plucking several hairs. hHF-MSCs were isolated from hair follicle tissues and their mesenchymal nature confirmed by detecting cell surface antigens and multilineage differentiation potential towards adipocytes and osteoblasts. They were then reprogrammed into iPSCs by lentiviral transduction with Oct4, Sox2, c-Myc and Klf4. hHF-MSC-derived iPSCs appeared indistinguishable from human embryonic stem cells (hESCs) in colony morphology, expression of alkaline phosphotase, and expression of specific hESCs surface markers, SSEA-3, SSEA-4, Tra-1-60, Tra-1-81, Nanog, Oct4, E-Cadherin and endogenous pluripotent genes. When injected into immunocompromised mice, hHF-MSC-derived iPSCs formed teratomas containing representatives of all three germ layers. This is the first study to report reprogramming of hHF-MSCs into iPSCs.     

诱导多功能干细胞的研究进展

背景：由于胚胎干细胞移植存在致瘤性和伦理学争议,有关胚胎干细胞的研究及临床应用存在较大的限制。2006年Yamanaka实验室利用Oct3/4、Sox2、Klf4、c-Myc 4 种因子将鼠成纤维细胞重编程为诱导多功能干细胞,标志着一种新型类胚胎干细胞的问世。 目的：了解诱导多功能干细胞的研究进展和应用前景。 方法：由第一作者检索2006/2010 PubMed 数据库(http://www.ncbi.nlm.nih.gov/PubMed)及万方数据库(http://g.wanfangdata.com.cn/)有关诱导多功能干细胞的产生、细胞特征、产生技术的研究进展及应用前景等方面的文章,英文检索词为“induced pluripotent stem cells,defined factors,reprogramming,vectors,disease”,排除重复性研究,共保留其中的69篇进行归纳总结。 结果与结论：诱导多功能干细胞研究在诱导因子种类,因子导入方式,重编程效率及应用研究等诸多方面取得进展。然而体细胞重编程为诱导多功能干细胞仍存在一定的风险,重编程效率还非常低。一旦解决诱导多功能干细胞的安全性和重编程效率问题,诱导多功能干细胞就可被广泛应用于疾病模型,药物测试,细胞移植及患者和疾病特异性多功能干细胞的建立等诸多方面。     

High efficiency of reprogramming CD34⁺ cells derived from human amniotic fluid into induced pluripotent stem cells with Oct4

Although many techniques can be used to generate multitype-induced pluripotent stem (iPS) cells from multitype seed cells, improving the efficiency and shortening the period of cell reprogramming remain troublesome issues. In this study, to generate iPS cells, CD34? cells, isolated from human amniotic fluid cells (HuAFCs) by flow cytometry, were infected with retroviruses carrying only one reprogramming factor (Oct4) and cultured on human amniotic epithelial cell (HuAEC) feeder layers. Approximately 4 to 5 days after viral infection, some embryonic stem cell (ESC)-like colonies appeared among the feeder cells. These colonies were positive for alkaline phosphatase and expressed high levels of ESC pluripotent markers (Nanog, Sox2, Oct4, CD133, and Rex1). Moreover, these iPS cells exhibited high levels of telomerase activity and had normal karyotypes. Additionally, these cells could differentiate into cell types from all 3 germ layers in vivo and in teratomas. In summary, we report a novel way of iPS generation that uses CD34? HuAFCs as seed cells. Using this method, we can generate human iPS cells with greater efficiency and safety (the oncogenic factors, c-Myc and Klf4, were not used), and using the minimum number of reprogramming factors (only one factor, Oct4). Besides, HuAECs were used as feeder layers to culture human iPS cells, which could not only avoid contamination with heterogeneous proteins, but also maintain iPS cells in a self-renewing and undifferentiated state for a long time.     

Analysis of Esg1 expression in pluripotent cells and the germline reveals similarities with Oct4 and Sox2 and differences between human pluripotent cell lines

Establishment of pluripotent epiblast cells is a critical event during early mammalian development because all somatic lineages and the primordial germ cells (PGCs) are derived from them. The epiblast and PGCs are in turn the precursors of pluripotent embryonic stem cells and embryonic germ cells, respectively. Although PGCs are specialized cells, they express several key pluripotency-related genes, such as Oct4 and Sox2. We have analyzed Esg1 expression in mouse and human cells and shown that in the mouse the gene is specifically expressed in preimplantation embryos, stem cells, and the germline. Moreover, Esg1 coexpresses with Oct4 and Sox2, confirming its identity as a marker of the pluripotent cycle. Esg1 is also expressed with Oct4 and Sox2 by human embryonic stem cells and in germ cell carcinoma tissue but not by all human embryonal carcinoma cell lines. These data suggest that together with Oct4 and Sox2, Esg1 plays a conserved role in the pluripotent pathway of mouse and human stem and germ cells.     

Generation of Induced Pluripotent Stem Cells From Buffalo (Bubalus bubalis) Fetal Fibroblasts with Buffalo Defined Factors

Ectopically, expression of defined factors could reprogram mammalian somatic cells into induced pluripotent stem cells (iPSCs), which initiates a new strategy to obtain pluripotent stem cell lines. Attempts have been made to generate buffalo pluripotent stem cells by culturing primary germ cells or inner cell mass, but the efficiency is extremely low. Here, we report a successful method to reprogram buffalo fetal fibroblasts (BFFs) into pluripotent stem cells [buffalo induced pluripotent stem cell (biPSCs)] by transduction of buffalo defined factors (Oct4, Sox2, Klf4, and c-Myc) using retroviral vectors. The established biPSCs displayed typical morphological characteristics of pluripotent stem cells, normal karyotype, positive staining of alkaline phosphatase, and expressed pluripotent markers including Oct4, Sox2, Nanog, Lin28, E-Cadherin, SSEA-1, SSEA-4, TRA-1-81, STAT3, and FOXD3. They could form embryoid bodies (EBs) in vitro and teratomas after injecting into the nude BALB/C mice, and 3 germ layers were identified in the EBs and teratomas. Methylation assay revealed that the promoters of Oct4 and Nanog were hypomethylated in biPSCs compared with BFFs and pre-biPSCs, while the promoters of Sox2 and E-Cadherin were hypomethylated in both BFFs and biPSCs. Further, inhibiting p53 expression by coexpression of SV40 large T antigen and buffalo defined factors in BFFs or treating BFFs with p53 inhibitor pifithrin-a (PFT) could increase the efficiency of biPSCs generation up to 3-fold, and nuclear transfer embryos reconstructed with biPSCs could develop to blastocysts. These results indicate that BFFs can be reprogrammed into biPSCs by buffalo defined factors, and the generation efficiency of biPSCs can be increased by inhibition of p53 expression. These efforts will provide a feasible approach for investigating buffalo stem cell signal pathways, establishing buffalo stem cell lines, and producing genetic modification buffaloes in the future.