Expression of markers for germ cells and oocytes in cow dermal fibroblast treated with 5-azacytidine and cultured in differentiation medium containing BMP2, BMP4 or follicular fluid

Pluripotent stem cell-derived gametes: A gap for infertility treatment and reproductive medicine in the future

Infertility affects 10-15 % of reproductive-age couples worldwide, with male infertility linked to sperm dysfunction and female infertility caused by ovulation disorders and reproductive abnormalities. Stem cell research presents a promising avenue for infertility treatment through germ cell differentiation. However, standardizing differentiation protocols and ensuring the functionality of in vitro-derived gametes remain significant challenges before clinical application becomes feasible.

Emerging Contributions of Pluripotent Stem Cells to Reproductive Technologies in Veterinary Medicine

The generation of mature gametes and competent embryos in vitro from pluripotent stem cells has been successfully achieved in a few species, mainly in mice, with recent advances in humans and scarce preliminary reports in other domestic species. These biotechnologies are very attractive as they facilitate the understanding of developmental mechanisms and stages that are generally inaccessible during early embryogenesis, thus enabling advanced reproductive technologies and contributing to the generation of animals of high genetic merit in a short period. Studies on the production of in vitro embryos in pigs and cattle are currently used as study models for humans since they present more similar characteristics when compared to rodents in both the initial embryo development and adult life. This review discusses the most relevant biotechnologies used in veterinary medicine, focusing on the generation of germ-cell-like cells in vitro through the acquisition of totipotent status and the production of embryos in vitro from pluripotent stem cells, thus highlighting the main uses of pluripotent stem cells in livestock species and reproductive medicine.

The Role of Bone Morphogenetic Protein 4 in Ovarian Function and Diseases

Bone morphogenetic proteins (BMPs) are the largest subfamily of the transforming growth factor-β (TGF-β) superfamily. BMP4 is a secreted protein that was originally identified due to its role in bone and cartilage development. Over the past decades, extensive literature has indicated that BMP4 and its receptors are widely expressed in the ovary. Dysregulation of BMP4 expression may play a vital role in follicular development, polycystic ovary syndrome (PCOS), and ovarian cancer. In this review, we summarized the expression pattern of BMP4 in the ovary, focused on the role of BMP4 in follicular development and steroidogenesis, and discussed the role of BMP4 in ovarian diseases such as polycystic ovary syndrome and ovarian cancer. Some studies have shown that the expression of BMP4 in the ovary is spatiotemporal and species specific, but the effects of BMP4 seem to be similar in follicular development of different species. In addition, BMP4 is involved in the development of hyperandrogenemia in PCOS and drug resistance in ovarian cancer, but further research is still needed to clarify the specific mechanisms.

5-Azacytidine pretreatment confers transient upregulation of proliferation and stemness in human mesenchymal stem cells

Successful outcomes of cell-based therapeutic is highly-dependent on quality and quantity of the cells. Epigenetic modifiers are known to modulate cell fates via reprogramming, hence it is plausible to use them in enhancing the plasticity of mesenchymal stem cells. In this study, we aimed to study the effects of 5-Azacytidine (5-AzaCR), an epigenetic modifier, pretreatment on mesenchymal stem cells-derived from Wharton's Jelly (WJMSCs) fates. WJMSCs were pretreated with 5-AzaCR for 24 h and subsequently cultured in culture media mixtures. The proliferative and stemness characteristics of the pretreated WJMSCs were assessed through morphological and gene expression analyses. Results showed that cells pretreated with 5 μM to 20 μM of 5-AzaCR showed to acquire higher proliferative state transiently when cultured in embryonic-mesenchymal stem cell (ESC-MSC) media, but not in MSC medium alone, and this coincides with significant transitional upregulation of stemness transcription factors. 5-AzaCR pretreatment has potential to confer initial induction of higher state of stemness and proliferation in WJMSCs, influenced by the culture media.

In Vitro Generation of Oocyte Like Cells and Their In Vivo Efficacy: How Far We have been Succeeded

In the last few decades, stem cell therapy has grown as a boon for many pathological complications including female reproductive disorders. In this review, a brief description of available strategies that are related to stem cell-based in vitro oocyte-like cell (OLC) development are given. We have tried to cover all the aspects and latest updates of the in vitro OLC developmental methodologies, marker profiling, available disease models, and in vivo efficacies, with a special focus on mesenchymal stem cells (MSCs), induced pluripotent stem cells (iPSCs), and embryonic stem cells (ESCs) usage. The differentiation abilities of both the ovarian and non-ovarian stem cell sources under various induction conditions have shown different effects on morphological alterations, proliferation- and size-associated developments, hormonal secretions under gonadotropic stimulations, and their neo-oogenesis or folliculogenesis abilities after in vivo transplantations. The attainment of characters like oocyte-like morphology, size expansion, and meiosis initiation have been found to be major obstacles during in vitro oogenesis. A number of reports have either lacked in vivo studies or have shown their functional incapability to produce viable and healthy offspring. Though researchers have gained many valuable insights regarding in vitro gametogenesis, still there are many things to do to make stem cell-derived OLCs fully functional.