Deconstructing human embryonic stem cell cultures: niche regulation of self-renewal and pluripotency

The factors and signaling pathways controlling pluripotent human cell properties, both embryonic and induced, have not been fully investigated. Failure to account for functional heterogeneity within human embryonic stem cell (hESC) cultures has led to inconclusive results in previous work examining extrinsic influences governing hESC fate (self renewal vs. differentiation vs. death). Here, we attempt to reconcile these inconsistencies with recent reports demonstrating that an autologously produced in vitro niche regulates hESCs. Moreover, we focus on the reciprocal paracrine signals within the in vitro hESC niche allowing for the maintenance and/or expansion of the hESC colony-initiating cell (CIC). Based on this, it is clear that separation of hESC-CICs, apart from their differentiated derivatives, will be essential in future studies involving their molecular regulation. Understanding how extrinsic factors control hESC self-renewal and differentiation will allow us to culture and differentiate these pluripotent cells with higher efficiency. This knowledge will be essential for clinical applications using human pluripotent cells in regenerative medicine.     

The Pursuit of ES Cell Lines of Domesticated Ungulates

In contrast to differentiated cells, embryonic stem cells (ESC) maintain an undifferentiated state, have the ability to self-renew, and exhibit pluripotency, i.e., they can give rise to most if not all somatic cell types and to the germ cells, egg and sperm. These characteristics make ES cell lines important resources for the advancement of human regenerative medicine, and, if established for domesticated ungulates, would help make possible the improvement of farm animals through their contribution to genetic engineering technology. Combining other genetic engineering technologies, such as somatic cell nuclear transfer with ESC technology may result in synergistic gains in the ability to precisely make and study genetic alterations in mammals. Unfortunately, despite significant advances in our understanding of human and mouse ESC, the derivation of ES cell lines from ungulate species has been unsuccessful. This may result from a lack of understanding of species-specific mechanisms that promote or influence cell pluripotency. Thorough molecular characterizations, including the elucidation of stem cell “marker” signaling cascade hierarchy, species-appropriate pluripotency markers, and pluripotency-associated chromatin alterations in the genomes of ungulate species, should improve the chances of developing efficient, reproducible technologies for the establishment of ES cell lines of economically important species like the pig, cow, goat, sheep and horse. Mention of a trade name, proprietary product or vendor does not constitute a guarantee or warranty of the product by USDA or imply its approval to the exclusion of other suitable products or vendors.     

Human embryonic stem cells: a model for human ageing in vitro

Stem cells have been used to investigate developmental processes and may be used as a therapeutic source of material for regenerative medicine and cancer. Here we propose the use of human embryonic stem cells, which represent a youthful phenotype, as models for experimentally investigating human ageing.     

In vitro culture and morphological characterization of prepubertal buffalo (Bubalus bubalis) putative spermatogonial stem cell

Purpose

Spermatogonial stem cells (SSCs) have the unique ability both to self-renew and to produce progeny that undergo differentiation to spermatozoa. The present study has been carried out to develop a method to purify and enrich the pure populations of spermatogonial stem cell like cells in buffalo.

Methods

The spermatogonial cells were isolated from testes of 3–7 month old buffalo calves and disaggregated by double enzymatic digestion. Mixed population of isolated cells were then plated on Datura stramonium agglutinin (DSA) lectin coated dishes for attachment of Sertoli cells. The desired cells were obtained from suspension medium after 18 h of incubation and then loaded on discontinuous density gradient using percoll (20–65 %) and different types of spermatogonia cells were obtained at interface of each layer. These cells were cultured in vitro.

Results

Spermatogonial cells isolated have spherical outline and two or three eccentrically placed nucleoli, created a colony after proliferation during first week or immediately after passage. After 7–10 days of culture, the resulted developed colonies of spermatogonial cells expressed the spermatogonial specific genes like Plzf and VASA; and other pluripotency related markers viz. alkaline phosphtase, DBA, CD9, CD90, SSEA-1, OCT-4, NANOG and REX-1.

Conclusion

Our results show that the isolated putative spermatogonial stem cells exhibit the expression of pluripotency related and spermatogonial specific genes. This study may help to establish a long term culture system for buffalo spermatogonia.     

Important role of glutathione in stemness and regulation of stem cells北大核心

BACKGROUND: Stem cells possess the capacities of self-renewal and multiple differentiation. Glutathione, an important sulfhydryl compounds, not only participates in the active oxygen metabolism of stem cells, but also plays an important role in self-renewal, proliferation, aging, stemness maintenance and differentiation regulation of stem cells. OBJECTIVE: To explore the important role of glutathione in stem cells. METHODS: In April 2020, the first author searched the title/abstract with the English keywords of “glutathione or GSH, stem cell”, and searched any field with the Chinese keywords of “glutathione, stem cell”, and searched the related articles included in CNKI, VIP, Wanfang and PubMed databases from 2000 to 2020. A total of 358 Chinese articles and 405 English articles were retrieved. Finally, 86 eligible articles were enrolled for the analysis after deleting the repetitive and non-conforming articles. RESULTS AND CONCLUSION: By reviewing the recent studies on glutathione and stem cells, we found that glutathione played an important role in maintaining stemness, regulating the differentiation of stem cells. In addition, effects of glutathione on cancer stem cells have been verified, which provides more evidence for the future treatment of cancer with reduced glutathione. Key words:. © 2022, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.