Knockout Serum Replacement (KSR) Has a Suppressive Effect on Sendai Virus-Mediated Transduction of Cynomolgus ES Cells

Effects of different culture systems on the culture of prepuberal buffalo (Bubalus bubalis) spermatogonial stem cell-like cells in vitro

Currently, the systems for culturing buffalo spermatogonial stem cells (SSCs) in vitro are varied, and their effects are still inconclusive. In this study, we compared the effects of culture systems with undefined (foetal bovine serum) and defined (KnockOut Serum Replacement) materials on the in vitro culture of buffalo SSC-like cells. Significantly more DDX4- and UCHL1-positive cells (cultured for 2 days at passage 2) were observed in the defined materials culture system than in the undefined materials system (p < 0.01), and these cells were maintained for a longer period than those in the culture system with undefined materials (10 days vs. 6 days). Furthermore, NANOS2 (p < 0.05), DDX4 (p < 0.01) and UCHL1 (p < 0.05) were expressed at significantly higher levels in the culture system with defined materials than in that with undefined materials. Induction with retinoic acid was used to verify that the cultured cells maintained SSC characteristics, revealing an SCP3⁺ subset in the cells cultured in the defined materials system. The expression levels of Stra8 (p < 0.05) and Rec8 (p < 0.01) were significantly increased, and the expression levels of ZBTB16 (p < 0.01) and DDX4 (p < 0.05) were significantly decreased. These findings provided a clearer research platform for exploring the mechanism of buffalo SSCs in vitro.

Efficient genetic modification of cynomolgus monkey embryonic stem cells with lentiviral vectors

Embryonic stem (ES) cells have the ability to undergo indefinite self-renewal in vitro and give rise during development to derivatives of all three primary germ layers (ectoderm, endoderm, and mesoderm), which make them a highly prized reagent in cell and gene therapy. Efficient introduction of various genes of interest into primate ES cells has proven to be difficult. Here, we demonstrated that the self-inactivating HIV-1-based lentiviral vectors constructed by MultiSite gateway technology are efficient tools for the transduction of cynomolgus monkey (Macaca fasicularis) ES (cmES) cells. After antibiotic selection, all of the transduced cells can stably express the reporter gene (humanized Renilla GFP or dTomato) while maintaining their stem cell properties, including continuous expression of stem cell markers, alkaline phosphatase (AKP), OCT-4, SSEA-4, and TRA-1-60, formation of embryoid bodies in vitro and teratomas in vivo containing derivatives of three embryonic germ layers. This approach will provide a useful tool for both gene function studies and in vivo cell tracking of stem cells.