Derivation of Intermediate Pluripotent Stem Cells Amenable to Primordial Germ Cell Specification

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Stem cells for reprogramming: could hUMSCs be a better choice?

Human umbilical cord mesenchymal stem cells (hUMSC) are primitive multipotent cells capable of differentiating into cells of different lineages. They can be an alternative source of pluripotent cells since they are ethically and regulatory approved, are easily obtained and have low immunogenicity compared to embryonic stem cells which are dogged with numerous controversies. hUMSC can be a great source for cell and transplantation therapy.     

Derivation and characterization of human embryonic stem cell lines from the Chinese population

Human embryonic stem cells(hESCs) can self-renew indefinitely and differentiate into all cell types in the human body.Therefore,they are valuable in regenerative medicine,human developmental biology and drug discovery.A number of hESC lines have been derived from the Chinese population, but limited of them are available for research purposes.Here we report the derivation and characterization of two hESC lines derived from human blastocysts of Chinese origin.These hESCs express alkaline phosphatase and hE...     

胰岛类器官研究进展

类器官是将具有多向分化潜能的干细胞或组织细胞在特定环境下培养分化成为能够模拟原生器官结构和功能的三维结构.类器官在各种疾病模型研究及药物筛选中发挥至关重要的作用.近年来,通过体外诱导胰腺组织或多能干细胞分化形成具有胰岛细胞功能的胰岛类器官研究成为热点,为胰岛相关疾病模型、药物研究以及糖尿病的治疗提供了新的手段.本文针对...     

Generation of rabbit pluripotent stem cell lines

Pluripotent stem cells have the capacity to divide indefinitely and to differentiate into all somatic cells and tissue lines. They can be genetically manipulated in vitro by knocking genes in or out, and therefore serve as an excellent tool for gene function studies and for the generation of models for some human diseases. Since 1981, when the first mouse embryonic stem cell (ESC) line was generated, many attempts have been made to generate pluripotent stem cell lines from other species. Comparative characterization of ESCs from different species would help us to understand differences and similarities in the signaling pathways involved in the maintenance of pluripotency and the initiation of differentiation, and would reveal whether the fundamental mechanism controlling self-renewal of pluripotent cells is conserved across different species. This report gives an overview of research into embryonic and induced pluripotent stem cells in the rabbit, an important nonrodent species with considerable merits as an animal model for specific diseases. A number of putative rabbit ESC and induced pluripotent stem cell lines have been described. All of them expressed stem cell-associated markers and maintained apparent pluripotency during multiple passages in vitro, but none have been convincingly proven to be fully pluripotent in vivo. Moreover, as in other domestic species, the markers currently used to characterize the putative rabbit ESCs are suboptimal because recent studies have revealed that they are not always specific to the pluripotent inner cell mass. Future validation of rabbit pluripotent stem cells would benefit greatly from a validated panel of molecular markers specific to pluripotent cells of the developing rabbit embryos. Using rabbit-specific pluripotency genes may improve the efficiency of somatic cell reprogramming for generating induced pluripotent stem cells and thereby overcome some of the challenges limiting the potential of this technology.     

Activin A and Wnt-dependent specification of human definitive endoderm cells

Activin/Nodal and Wnt signaling are known to play important roles in the regional specification of endoderm. Here we have investigated the effect of the length of stimulation with Activin A plus Wnt3a on the development of hepatic and pancreatic progenitors from the definitive endoderm (DE) cells derived from human pluripotent stem cells (hPSC). We show that DE-cells derived from hPSC with 3 days high Activin A and Wnt3a treatment were able to differentiate further into both tested endodermal lineages. When prolonging the DE-induction protocol from 3 to 5 or 7 days, almost pure DE-marker positive cell populations were obtained. However, these cells had an impaired pancreatic differentiation capacity, while they still developed into hepatocyte-like cells. Further propagation of the DE-cells in the presence of Wnt3a and Activin A led to the complete loss of differentiation capacity into hepatic or pancreatic lineages. When Wnt3a was removed after 24 h from the initiation of the differentiation, the cells were able to differentiate into PDX1+/NKX6.1+ pancreatic progenitors even with longer DE induction time while efficiency of hepatic differentiation was lower. Our results suggest that both the length and the timing of Wnt3a treatment during DE induction are crucial for the final differentiation outcome. Although it is possible to derive apparently pure DE cells with prolonged Activin A/Wnt-stimulation, their progenitor capacity is restricted to a limited time window.     

Artificial niche substrates for embryonic and induced pluripotent stem cell cultures

Stem cells possess the ability to self-renew and differentiate into other cell types. In vivo, stem cells reside in their own anatomic niches in a defined physiological environment, from which they are released to differentiate into a required cell type when deemed appropriate. While a resident within the niche, the stem cell receives signals that in turn maintain the cell in a pluripotent state. In addition, the niche also provides nourishment to the cell. Physically, the niche also serves to anchor the cell via various ECM components and cell-adhesion molecules. Therefore, in vitro models that replicate the in vivo niche will lead to a better understanding of stem cell fate and turnover. In turn, this will help inform attempts to culture stem cells in vitro on artificial niche-like substrates. In this review, we have highlighted recent studies describing artificial niche-like substrates used to culture embryonic and induced pluripotent stem cells in vitro.     

无异源培养条件下人多能干细胞系H1非病毒转染方法的比较和优化

目的将人类多能干细胞（hPSCs）进行基因编辑和分化是干细胞治疗的发展趋势。所以在无异源（Xeno-free）的培养条件下,系统地比较研究非病毒的干细胞转染方法有助于临床科研的发展。 方法采用E8和Vitronectin人类干细胞Xeno-free培养系统培养人类H1干细胞系,从细胞活力、干细胞分化标记和转染效率三个方面比较并优化了3种主流的非病毒转染方法,分为空白对照组（正常培养的H1,未做任何处理）、转染GFP荧光质粒的电转组、脂质体组和磷酸钙组。多组间比较采用单因素方差分析和Tukey多重比较。 结果3种转染方法对H1细胞的分化都没有显著的影响,转染后各组99.4﹪以上的细胞分型为SSEA1^-TRA-1-60⁺。从形态上观察,磷酸钙转染对干细胞损伤严重;电转和脂质体转染对细胞的损伤较小,且可以在Xeno-free培养系统下对干细胞形成有效转染。转染效率方面：优化前,与对照组、电转组、磷酸钙组的GFP阳性细胞率[（0.46±0.10）﹪、（0.06±0.10）﹪、（0.14±0.24）﹪]相比,脂质体组的转染效率（7.99±0.47）﹪最高（P均< 0.01）。优化试剂浓度和程序后,电转组的转染效率升高到（65.47±3.07）﹪,比优化后的脂质体组和磷酸钙组的效率都要高[（14.7±0.26）﹪和（4.84±0.25）﹪],差异有统计学意义（P < 0.01）。 结论电转和脂质体转染适用于Xeno-free培养系统下人类多能干细胞系H1的转染,优化后利用电转程序A13转染H1细胞可以获得本实验中最高的转染效率。