Effects of various culture conditions on pluripotent stem cell derivation from chick embryos

The Effect of Inhibiting the Wingless/Integrated (WNT) Signaling Pathway on the Early Embryonic Disc Cell Culture in Chickens

The utilization of chicken embryonic-derived pluripotent stem cell (PSC) lines is crucial in various fields, including growth and development, vaccine and protein production, and germplasm resource protection. However, the research foundation for chicken PSCs is relatively weak, and there are still challenges in establishing a stable and efficient PSC culture system. Therefore, this study aims to investigate the effects of the FGF2/ERK and WNT/β-catenin signaling pathways, as well as different feeder layers, on the derivation and maintenance of chicken embryonic-derived PSCs. The results of this study demonstrate that the use of STO cells as feeder layers, along with the addition of FGF2, IWR-1, and XAV-939 (FIX), allows for the efficient derivation of chicken PSC-like cells. Under the FIX culture conditions, chicken PSCs express key pluripotency genes, such as POUV, SOX2, and NANOG, as well as specific proteins SSEA-1, C-KIT, and SOX2, indicating their pluripotent nature. Additionally, the embryoid body experiment confirms that these PSC-like cells can differentiate into cells of three germ layers in vitro, highlighting their potential for multilineage differentiation. Furthermore, this study reveals that chicken Eyal-Giladi and Kochav stage X blastodermal cells express genes related to the primed state of PSCs, and the FIX culture system established in this research maintains the expression of these genes in vitro. These findings contribute significantly to the understanding and optimization of chicken PSC culture conditions and provide a foundation for further exploration of the biomedical research and biotechnological applications of chicken PSCs.

Wnt signaling blockade is essential for maintaining the pluripotency of chicken embryonic stem cells

Activation of Wnt/β-catenin signaling supports the self-renewal of mouse embryonic stem cells. We aimed to understand the effects of Wnt signaling activation or inhibition on chicken embryonic stem cells (chESCs), as these effects are largely unknown. When the glycogen synthase kinase-3 β inhibitor CHIR99021-which activates Wnt signaling-was added to chESC cultures, the colony shape flattened, and the expression levels of pluripotency-related (NANOG, SOX2, SOX3, OCT4, LIN28A, DNMT3B, and PRDM14) and germ cell (CVH and DAZL) markers showed a decreasing trend, and the growth of chESCs was inhibited after approximately 7 d. By contrast, when the Wnt signaling inhibitor XAV939 was added to the culture, dense and compact multipotent colonies (morphologically similar to mouse embryonic stem cell colonies) showing stable expression of pluripotency-related and germline markers were formed. The addition of XAV939 stabilized the proliferation of chESCs in the early stages of culture and promoted their establishment. Furthermore, these chESCs formed chimeras. In conclusion, functional chESCs can be stably cultured using Wnt signaling inhibitors. These findings suggest the importance of Wnt/β-catenin signaling in avian stem cells, offering valuable insights for applied research using chESCs.

The constitutively active pSMAD2/3 relatively improves the proliferation of chicken primordial germ cells

In many multicellular organisms, mature gametes originate from primordial germ cells (PGCs). Improvements in the culture of PGCs are important not only for developmental biology research, but also for preserving endangered species, and for genome editing and transgenic animal technologies. SMAD2/3 appear to be powerful regulators of gene expression; however, their potential positive impact on the regulation of PGC proliferation has not been taken into consideration. Here, the effect of TGF-β signaling as the upstream activator of SMAD2/3 transcription factors was evaluated on chicken PGCs' proliferation. For this, chicken PGCs at stages 26-28 Hamburger-Hamilton were obtained from the embryonic gonadal regions and cultured on different feeders or feeder-free substrates. The results showed that TGF-β signaling agonists (IDE1 and Activin-A) improved PGC proliferation to some extent while treatment with SB431542, the antagonist of TGF-β, disrupted PGCs' proliferation. However, the transfection of PGCs with constitutively active SMAD2/3 (SMAD2/3CA) resulted in improved PGC proliferation for more than 5 weeks. The results confirmed the interactions between overexpressed SMAD2/3CA and pluripotency-associated genes NANOG, OCT4, and SOX2. According to the results, the application of SMAD2/3CA could represent a step toward achieving an efficient expansion of avian PGCs.

Blood Pharming – eine realistische Option?

Die Bluttransfusion ist ein wesentlicher und unersetzlicher Teil der modernen Medizin. Jedoch stellt vor allem bei Patienten mit sehr seltenen Blutgruppenkonstellationen der Mangel an Blutprodukten auch heute noch ein wichtiges Gesundheitsproblem weltweit dar. Um diesem Problem entgegenzutreten, versucht man seit einiger Zeit künstlich rote Blutzellen zu generieren. Diese haben potenzielle Vorteile gegenüber Spenderblut, wie z. B. ein verringertes Risiko für die Übertragung von Infektionskrankheiten. Diese Übersicht fasst die aktuellen Entwicklungen über den Prozess der Erythropoese, die Expansionsstrategien der erythrozytären Zellen, der verschiedenen Quellen für ex vivo expandierte Erythrozyten, die Hürden für die klinische Anwendung und die zukünftigen Möglichkeiten der Anwendung zusammen.

Differentiation of human induced pluripotent stem cells into erythroid cells

During the last years, several strategies have been made to obtain mature erythrocytes or red blood cells (RBC) from the bone marrow or umbilical cord blood (UCB). However, UCB-derived hematopoietic stem cells (HSC) are a limited source and in vitro large-scale expansion of RBC from HSC remains problematic. One promising alternative can be human pluripotent stem cells (PSCs) that provide an unlimited source of cells. Human PSCs, including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), are self-renewing progenitors that can be differentiated to lineages of ectoderm, mesoderm, and endoderm. Several previous studies have revealed that human ESCs can differentiate into functional oxygen-carrying erythrocytes; however, the ex vivo expansion of human ESC-derived RBC is subjected to ethical concerns. Human iPSCs can be a suitable therapeutic choice for the in vitro/ex vivo manufacture of RBCs. Reprogramming of human somatic cells through the ectopic expression of the transcription factors (OCT4, SOX2, KLF4, c-MYC, LIN28, and NANOG) has provided a new avenue for disease modeling and regenerative medicine. Various techniques have been developed to generate enucleated RBCs from human iPSCs. The in vitro production of human iPSC-derived RBCs can be an alternative treatment option for patients with blood disorders. In this review, we focused on the generation of human iPSC-derived erythrocytes to present an overview of the current status and applications of this field.

Supervivencia de células fibroblásticas humanas en ausencia de suplementación

Introducción. Los fibroblastos gingivales (FGs) son células del tejido conjuntivo gingival que han tomado en los últimos años una relevancia promisoria por su probable utilización en la terapia celular, dadas sus capacidades de multipotencialidad y de autorrenovación. Objetivo. Conocer y describir el impacto de la ausencia en la suplementación de Suero Fetal Bovino (SFB) en la supervivencia de fibroblastos gingivales en cultivos. Materiales y métodos. Fibroblastos gingivales fueron aislados de tejido gingival de pacientes sanos y cultivados en medios de cultivos DMEM (Dulbecco’s Modified of Eagle Medium) en ausencia y suplementados con 0.2% de SFB a 37°C en una atmósfera húmeda con 5% de CO2. Se llevó a cabo una evaluación morfológica, de supervivencia y proliferación de los FGs, así como la identificación mediante la técnica de inmunofluorescencia de marcadores del citoesqueleto celular como la actina y mitocondrias. Resultados. Los FGs cultivados en ausencia y con suplementación de 0.2% de SFB evidenciaron una forma fusiforme, con núcleos ovalados y numerosas prolongaciones citoplasmáticas durante el tiempo de cultivo. Un leve aumento en la proliferación de FGs fue observado en aquellas células en contacto con el medio DMEM+0.2% de SFB comparadas con el medio donde estuvo ausente la suplementación. El inmunomarcaje de la actina y las mitocondrias dejó en evidencia que la ausencia y suplementación a 0.2% de SFB no afectó su localización en los FGs evaluados. Conclusión. Los fibroblastos gingivales sobreviven y proliferan en ausencia de SFB, conservando sus características morfológicas celulares.

Advances in Isolation and Culture of Chicken Embryonic Stem Cells In Vitro

Chicken embryonic stem cells (cESCs) isolated from the egg at the stage X hold great promise for cell therapy, tissue engineering, pharmaceutical, and biotechnological applications. They are considered to be pluripotent cells with the capacity to self-renewal and differentiate into specialized cells. However, long-term maintenance of cESCs cannot be realized now, which impedes the establishment of cESC line and limits their applications. Therefore, the separation locations, isolation methods, and culture conditions especially the supplements and action mechanisms of cytokines, including leukemia inhibitory factor, fibroblast growth factor, transforming growth factor beta, bone morphogenic protein, and activin for cESCs in vitro, have been reviewed here. These defined strategies will contribute to identify the key mechanism on the self-renewal of cESCs, facilitate to optimize system that supports the derivation and longtime maintenance of cESCs, establish the cESC line, and develop the biobank of genetic resources in chicken.

Suppression of TGF-β and ERK Signaling Pathways as a New Strategy to Provide Rodent and Non-Rodent Pluripotent Stem Cells

Stem cells are unspecialized cells and excellent model in developmental biology and a promising approach to the treatment of disease and injury. In the last 30 years, pluripotent embryonic stem (ES) cells were established from murine and primate sources, and display indefinite replicative potential and the ability to differentiate to all three embryonic germ layers. Despite large efforts in many aspects of rodent and non-rodent pluripotent stem cell culture, a number of diverse challenges remain. Natural and synthetic small molecules (SMs) strategy has the potential to overcome these hurdles. Small molecules are typically fast and reversible that target specific signaling pathways, epigenetic processes and other cellular processes. Inhibition of the transforming growth factor-β (TGF-β/Smad) and fibroblast growth factor 4 (FGF4)/ERK signaling pathways by SB431542 and PD0325901 small molecules, respectively, known as R2i, enhances the efficiency of mouse, rat, and chicken pluripotent stem cells passaging from different genetic backgrounds. Therefore, the application of SM inhibitors of TGF-β and ERK1/2 with leukemia inhibitory factor (LIF) allows the cultivation of pluripotent stem cells in a chemically defined condition. In this review, we discuss recently emerging evidence that dual inhibition of TGF-β and FGF signaling pathways plays an important role in regulating pluripotency in both rodent and non-rodent pluripotent stem cells.

Transition of inner cell mass to embryonic stem cells: mechanisms, facts, and hypotheses

Embryonic stem cells (ESCs) are immortal stem cells that own multi-lineage differentiation potential. ESCs are commonly derived from the inner cell mass (ICM) of pre-implantation embryos. Due to their tremendous developmental capacity and unlimited self-renewal, ESCs have diverse biomedical applications. Different culture media have been developed to procure and maintain ESCs in a state of naïve pluripotency, and to preserve a stable genome and epigenome during serial passaging. Chromatin modifications such as DNA methylation and histone modifications along with microRNA activity and different signaling pathways dynamically contribute to the regulation of the ESC gene regulatory network (GRN). Such modifications undergo remarkable changes in different ESC media and determine the quality and developmental potential of ESCs. In this review, we discuss the current approaches for derivation and maintenance of ESCs, and examine how differences in culture media impact on the characteristics of pluripotency via modulation of GRN during the course of ICM outgrowth into ESCs. We also summarize the current hypotheses concerning the origin of ESCs and provide a perspective about the relationship of these cells to their in vivo counterparts (early embryonic cells around the time of implantation). Finally, we discuss generation of ESCs from human embryos and domesticated animals, and offer suggestions to further advance this fascinating field.

Efficient Production of Biallelic RAG1 Knockout Mouse Embryonic Stem Cell Using CRISPR/Cas9

Background

Recombination Activating Genes (RAG) mutated embryonic stem cells are (ES) cells which are unable to perform V (D) J recombination. These cells can be used for generation of immunodeficient mouse. Creating biallelic mutations by CRISPR/Cas9 genome editing has emerged as a powerful technique to generate site-specific mutations in different sequences.

Objectives

The main purposes of this study were to achieve complete knock-out of RAG1 gene by investigating the nature of mutations in mutant mESC and to generate RAG1 knock-out mESCs containing homozygous indels with the aim of creating desired and specific RAG-1 -/- mutant mouse in a shorter period of time.

Materials and Methods

Here, we first utilized CRISPR/Cas9 system to target RAG1/RAG2 genes in NIH3T3 cells to test the activity and efficiency of our CRISPR system. Then we used the system for targeting RAG1 gene in mouse embryonic stem cell (mESCs) to generate knock-out embryonic stem cells. This method combined with highly active single guide RNA (sgRNA) is an efficient way to produce new RAG1-knockout mESCs in the selected regions of early coding DNA sequence, approximately between nucleotide c. 512-c. 513 and nucleotide c. 725-c. 726 of RAG1 coding sequence that had not been targeted previously.

Results

CRISPR gene editing resulted in a multitude of engineered homozygous and compound heterozygous mutations, including both in-frame and out-of-frame indels in 92% of mES cell clones. Most of the mutations generated by CRISPR/Cas9 system were out-of-frame, resulting in a complete gene knockout. In addition, 59% of the mutant ES cell clones carried out-of-frame homozygous indel mutations. The RAG1-knockout mESC clones retained normal morphology and pluripotent gene expression.

Conclusions

Our study demonstrated that CRISPR/Cas9 system can efficiently create biallelic indels containing both homozygous and compound heterozygous RAG1 mutations in about 92% of the mutant mESC clones. The 59% of mutant ES cell clones carried out-of-frame homozygous indel mutations.