GSK-3 signaling is involved in proliferation of chicken primordial germ cells

Identification of key events and regulatory networks in the formation process of primordial germ cell based on proteomics

Currently, studies have analyzed the formation mechanism of primordial germ cell (PGC) at the transcriptional level, but few at the protein level, which made the mechanism study of PGC formation not systematic. Here, we screened differential expression proteins (DEPs) regulated PGC formation by label-free proteomics with a novel sampling strategy of embryonic stem cells and PGC. Analysis of DEPs showed that multiple key events were involved, such as the transition from glycolysis to oxidative phosphorylation, activation of autophagy, low DNA methylation ensured the normal formation of PGC, beyond that, protein ubiquitination also played an important role in PGC formation. Importantly, the progression of such events was attributed to the inconsistency between transcription and translation. Interestingly, MAPK, PPAR, Wnt, and JAK signaling pathways not only interact with each other but also interact with different events to participate in the formation of PGC, which formed the PGC regulatory network. According to the regulatory network, the efficiency of PGC formation in induction system can be significantly improved. In conclusion, our results indicate that chicken PGC formation is a complex process involving multiple events and signals, which provide technical support for the specific application in PGC research.

Fate Decisions of Chicken Primordial Germ Cells (PGCs): Development, Integrity, Sex Determination, and Self-Renewal Mechanisms

Primordial germ cells (PGCs) are precursor cells of sperm and eggs. The fate decisions of chicken PGCs in terms of their development, integrity, and sex determination have unique features, thereby providing insights into evolutionary developmental biology. Additionally, fate decisions in the context of a self-renewal mechanism have been applied to establish culture protocols for chicken PGCs, enabling the production of genome-edited chickens and the conservation of genetic resources. Thus, studies on the fate decisions of chicken PGCs have significantly contributed to both academic and industrial development. Furthermore, studies on fate decisions have rapidly advanced owing to the recent development of essential research technologies, such as genome editing and RNA sequencing. Here, we reviewed the status of fate decisions of chicken PGCs and provided insight into other important research issues that require attention.

BDE-209 disturbed proliferation and differentiation of spermatogonia during mitotic process through estrogen receptor α

Deca-bromodiphenyl ether (BDE-209) exposure caused spermatogenesis disorder resulting in poor sperm quality has become a public concern in recent years. Spermatogenesis refers to the process by which the division of spermatogonia stem cells (SSCs) produces haploid spermatozoa, including mitosis, meiosis, and spermiogenesis. However, the mechanism of mitosis including proliferation and differentiation of spermatogonia dysfunction induced by BDE-209 remains largely unclear. Here, our data showed that BDE-209 exposure caused a decline in sperm quality with seminiferous tubule structure disorder in rats. In addition, BDE-209 exposure damage spermatogonia proliferation and differentiation with decreasing level of PLZF and cKit in testis. Moreover, rats exposed to BDE-209 decreased the expression of ERα, whereas an elevated expression of Wnt3a and Wnt5a. Mechanistically, supplementation with propipyrazole triol (PPT, a selective ERα pathway agonist) rescued sperm quality and attenuated impairment of proliferation and differentiation of spermatogonia in BDE-209-induced rats. Therefore, ERα plays a crucial role in the proliferation and differentiation of spermatogonia during mitotic process. In conclusion, our study clarified the role of ERα in BDE-209-induced spermatogonia proliferation and differentiation in rats and provides a potential therapeutic application on poor sperm quality caused by BDE-209 exposure.

Germline stem cells in human

The germline cells are essential for the propagation of human beings, thus essential for the survival of mankind. The germline stem cells, as a unique cell type, generate various states of germ stem cells and then differentiate into specialized cells, spermatozoa and ova, for producing offspring, while self-renew to generate more stem cells. Abnormal development of germline stem cells often causes severe diseases in humans, including infertility and cancer. Primordial germ cells (PGCs) first emerge during early embryonic development, migrate into the gentile ridge, and then join in the formation of gonads. In males, they differentiate into spermatogonial stem cells, which give rise to spermatozoa via meiosis from the onset of puberty, while in females, the female germline stem cells (FGSCs) retain stemness in the ovary and initiate meiosis to generate oocytes. Primordial germ cell-like cells (PGCLCs) can be induced in vitro from embryonic stem cells or induced pluripotent stem cells. In this review, we focus on current advances in these embryonic and adult germline stem cells, and the induced PGCLCs in humans, provide an overview of molecular mechanisms underlying the development and differentiation of the germline stem cells and outline their physiological functions, pathological implications, and clinical applications.

3D printing of chemical-empowered tendon stem/progenitor cells for functional tissue repair

Tendon injuries are the leading cause of chronic debilitation to patients. Tendon stem/progenitor cells (TSPCs) are potential seed cells for tendon tissue engineering and regeneration, but TSPCs are prone to lose their distinct phenotype in vitro and specific differentiation into the tenocyte lineage is challenging. Utilizing small molecules in an ex vivo culture system may be a promising solution and can significantly improve the therapeutic applications of these cells. Here, by using an image-based, high-throughput screening platform on small molecule libraries, this study established an effective stepwise culture strategy for TSPCs application. The study formulated a cocktail of small molecules which effected proliferation, tenogenesis initiation and maturation phases, and significantly upregulated expression of various tendon-related genes and proteins in TSPCs, which were demonstrated by high-throughput PCR, ScxGFP reporter assay and immunocytochemistry. Furthermore, by combining small molecule-based culture system with 3D printing technology, we embedded living, chemical-empowered TSPCs within a biocompatible hydrogel to engineer tendon grafts, and verified their enhanced ability in promoting functional tendon repair and regeneration both in vivo and in situ. The stepwise culture system for TSPCs and construction of engineered tendon grafts can not only serve as a platform for further studies of underlying molecular mechanisms of tenogenic differentiation, but also provide a new strategy for tissue engineering and development of novel therapeutics for clinical applications.