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。     

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.     

Embryonic stem cell markers Sox-2 and OCT4 expression and their correlation with WNT signal pathway in cervical squamous cell carcinoma

Background: Both the expression of embryonic stem cells (ESCs) markers (Sox2, Oct4) and the Wnt signal pathway (β-catenin) are crucial for progression of various human malignancies. The purpose of this study was to investigate the clinicopathologic significance of Sox2, Oct4 and β-catenin in cervical squamous cell carcinoma (CSCC) and to study their correlation with the occurrence and prognosis. Methods: Sox2, Oct4 and β-catenin were assessed using immunohistochemistry in normal cervix tissues (n = 28) and invasive cervical squamous cell carcinoma (n = 43). Associations of Sox2, Oct4 and β-catenin levels with clinicopathological characteristics and with overall survival were studied using uni- and multivariate analysis. Results: The expression levels of Sox2, Oct4 and β-catenin were highly increased in CSCC compared with the normal cervix tissues. The ESCs markers expression (Sox2 and Oct4) correlated significantly with β-catenin expression. High expression of Sox2, but not that of Oct4 or β-catenin, was correlated with poorer differentiation (P < 0.05). Furthermore, Sox2 expression was significantly correlated with patients’ status of survival in advanced CSCC (P < 0.05), whereas there was no significant finding in Oct4 or β-catenin expression. Conclusions: These findings provide evidence that both ESCs biomarkers (Sox2, Oct4) and Wnt signal pathway (β-catenin) are activated in CSCC. Sox2 can be regarded as a novel predictor of poor prognosis for CSCC patients.     

人诱导性多潜能干细胞系的建立

背景：诱导性多潜能干细胞与肿瘤干细胞的发生过程极其相似,而且具有的干细胞特性极其接近人胚胎干细胞。因此,研究诱导性多潜能干细胞有利于人们进一步认识并了解人类发育以及肿瘤的发生过程。 目的：掌握建立人诱导性多潜能干细胞系的技术,以便为特异性疾病细胞的重编程建立技术平台,从而利用重编程技术研究疾病的发病机制。 方法：将含有Oct4、Sox2、Klf-4和c-Myc 4个转录因子的反转录病毒感染人皮肤成纤维细胞(HS27细胞),在人胚胎干细胞培养条件下诱导产生人胚胎干细胞样的克隆。挑取并进一步扩增,通过克隆形态、碱性磷酸酶活性、免疫荧光检测是否有人胚胎干细胞标记物Oct4、Sox2、c-Myc、Klf-4的表达,悬滴法检测HS27细胞来源的克隆形成畸胎瘤的能力和验证向3个胚层的分化能力。 结果与结论：经病毒感染诱导产生的胚胎干细胞样克隆呈绿色荧光蛋白阴性,克隆在细胞形态方面与人胚胎干细胞克隆相似,进一步扩增经碱性磷酸酶检测克隆呈阳性,免疫荧光检测克隆表达Oct4、Sox2、c-Myc、Klf-4,并且HS27细胞来源的克隆注入免疫缺陷小鼠体内可以形成畸胎瘤并经苏木精-伊红染色显示具有向三胚层分化能力。实验成功构建了人诱导性多潜能干细胞系,为下一步开展疾病细胞特异性重编程研究奠定了良好的实验基础。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

Two-phase analysis of molecular pathways underlying induced pluripotent stem cell induction

Induced pluripotent stem cells (iPSCs) can be reprogrammed from adult somatic cells by transduction with Oct4, Sox2, Klf4, and c-Myc, but the molecular cascades initiated by these factors remain poorly understood. Impeding their elucidation is the stochastic nature of the iPS induction process, which results in heterogeneous cell populations. Here we have synchronized the reprogramming process by a two-phase induction: an initial stable intermediate phase following transduction with Oct4, Klf4, and c-Myc, and a final iPS phase following overexpression of Sox2. This approach has enabled us to examine temporal gene expression profiles, permitting the identification of Sox2 downstream genes critical for induction. Furthermore, we have validated the feasibility of our new approach by using it to confirm that downregulation of transforming growth factor β signaling by Sox2 proves essential to the reprogramming process. Thus, we present a novel means for dissecting the details underlying the induction of iPSCs, an approach with significant utility in this arena and the potential for wide-ranging implications in the study of other reprogramming mechanisms.     

Regulation of pluripotency in male germline stem cells by Dmrt1

Spermatogonial stem cells (SSCs) present the potential to acquire pluripotency under specific culture conditions. However, the frequency of pluripotent cell derivation is low, and the mechanism of SSC reprogramming remains unknown. In this study, we report that induction of global DNA hypomethylation in germline stem (GS) cells (cultured SSCs) induces pluripotent cell derivation. When DNA demethylation was triggered by Dnmt1 depletion, GS cells underwent apoptosis. However, GS cells were converted into embryonic stem (ES)-like cells by double knockdown of Dnmt1 and p53. This treatment down-regulated Dmrt1, a gene involved in sexual differentiation, meiosis, and pluripotency. Dmrt1 depletion caused apoptosis of GS cells, but a combination of Dmrt1 and p53 depletion also induced pluripotency. Functional screening of putative Dmrt1 target genes revealed that Dmrt1 depletion up-regulates Sox2. Sox2 transfection up-regulated Oct4 and produced pluripotent cells. This conversion was enhanced by Oct1 depletion, suggesting that the balance of Oct proteins maintains SSC identity. These results suggest that spontaneous SSC reprogramming is caused by unstable DNA methylation and that a Dmrt1–Sox2 cascade is critical for regulating pluripotency in SSCs.