Four recombinant pluripotency transcriptional factors containing a protein transduction domain maintained the in vitro pluripotency of chicken embryonic stem cells

Construction of a TAT-Cas9-EGFP Site-Specific Integration Eukaryotic Cell Line Using Efficient PEG10 Modification

The CRISPR/Cas9 system enables precise and efficient modification of eukaryotic genomes. Among its various applications, homology-directed repair (HDR) mediated knock-in (KI) is crucial for creating human disease models, gene therapy, and agricultural genetic enhancements. Despite its potential, HDR-mediated knock-in efficiency remains relatively low. This study investigated the impact of 5' end PEG10 modification on site-specific integration of the target gene. The HEK293 cell line is considered a highly attractive expression system for the production of recombinant proteins, with the construction of site-specific integration cell lines at the AAVS1 locus enabling stable protein expression. This study investigated the impact of the 5' end PEG10 modification on the site-specific integration of the target gene at the AAVS1 locus in the 293T cell line. Utilizing this 5' end PEG10 modification resulted in a 1.9-fold increase in knock-in efficiency for a 1.8 kb target fragment, improving efficiency from 26% to 49%. An optimized system was utilized to successfully establish a high-expression, site-specific integration 293T cell line for TAT-Cas9-EGFP, providing a reliable resource of seed cells for subsequent protein production.

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.

The evolution of chicken stem cell culture methods

1. The avian embryo is an excellent model for studying embryology and the production of pharmaceutical proteins in transgenic chickens. Furthermore, chicken stem cells have the potential for proliferation and differentiation and emerged as an attractive tool for various cell-based technologies. 2. The objective of these studies is the derivation and culture of these stem cells is the production of transgenic birds for recombinant biomaterials and vaccine manufacture, drug and cytotoxicity testing, as well as to gain insight into basic science, including cell tracking. 3. Despite similarities among the established chicken stem cell lines, fundamental differences have been reported between their culture conditions and applications. Recent conventional protocols used for expansion and culture of chicken stem cells mostly depend on feeder cells, serum-containing media and static culture. 4. Utilising chicken stem cells for generation of cell-based transgenic birds and a variety of vaccines requires large-scale cell production. However, scaling up the conventional adherent chicken stem cells is challenging and labour intensive. Development of a suspension cell culture process for chicken embryonic stem cells (cESCs), chicken primordial germ cells (PGCs) and chicken induced pluripotent stem cells (ciPSCs) will be an important advance for increasing the growth kinetics of these cells. 6. This review describes various approaches and suggestions to achieve optimal cell growth for defined chicken stem cells cultures and use in future manufacturing applications.

Sequence-defined shuttles for targeted nucleic acid and protein delivery

Molecular medicine opens into a space of novel specific therapeutic agents: intracellularly active drugs such as peptides, proteins or nucleic acids, which are not able to cross cell membranes and enter the intracellular space on their own. Through the development of cell-targeted shuttles for specific delivery, this restriction in delivery has the potential to be converted into an advantage. On the one hand, due to the multiple extra- and intracellular barriers, such carrier systems need to be multifunctional. On the other hand, they must be precise and reproducibly manufactured due to pharmaceutical reasons. Here we review the design of precise sequence-defined delivery carriers, including solid-phase synthesized peptides and nonpeptidic oligomers, or nucleotide-based carriers such as aptamers and origami nanoboxes.