Generation, characterization, and differentiation of induced pluripotent stem-like cells in the domestic cat

Induced pluripotent stem (iPS) cells are generated from somatic cells and can differentiate into various cell types. Therefore, these cells are expected to be a powerful tool for modeling diseases and transplantation therapy. Generation of domestic cat iPS cells depending on leukemia inhibitory factor has been reported; however, this strategy may not be optimized. Considering that domestic cats are excellent models for studying spontaneous diseases, iPS cell generation is crucial. In this study, we aimed to derive iPS cells from cat embryonic fibroblasts retrovirally transfected with mouse Oct3/4, Klf4, Sox2, and c-Myc. After transfection, embryonic fibroblasts were reseeded onto inactivated SNL 76/7 and cultured in a medium supplemented with basic fibroblast growth factor. Flat, compact, primary colonies resembling human iPS colonies were observed. Additionally, primary colonies were more frequently observed in the KnockOut Serum Replacement medium than in the fetal bovine serum (FBS) medium. However, enhanced maintenance and proliferation of iPS-like cells occurred in the FBS medium. These iPS-like cells expressed embryonic stem cell markers, had normal karyotypes, proliferated beyond 45 passages, and differentiated into all three germ layers in vitro. Notably, expression of exogenous Oct3/4, Klf4, and Sox2 was silenced in these cells. However, the iPS-like cells failed to form teratomas. In conclusion, this is the first study to establish and characterize cat iPS-like cells, which can differentiate into different cell types depending on the basic fibroblast growth factor.

Generation of Footprint-Free Canine Induced Pluripotent Stem Cells Using Auto-Erasable Sendai Virus Vector

Canine induced pluripotent stem cells (ciPSCs) can be used in regenerative medicine. However, there are no reports on the generation of genome integration-free and completely exogenous gene-silenced (footprint free) ciPSCs that are tolerant to enzymatic single-cell passage. In this study, we reprogrammed canine embryonic fibroblasts using the auto-erasable replication-defective and persistent Sendai virus vector, SeVdp(KOSM)302L, and generated two ciPSC lines. The ciPSCs were positive for pluripotent markers, including alkaline phosphatase activity as well as OCT3/4, SOX2, and NANOG transcripts, and NANOG, stage-specific embryonic antigen-1, and partial TRA-1-60 protein expression, even after SeVdp(KOSM)302L removal. The ciPSCs were induced to differentiate into all the three germ layers as embryoid bodies in vitro and as teratomas in vivo. Furthermore, SeVdp(KOSM)302L-free ciPSCs maintained a normal karyotype even after repeated enzymatic single-cell passaging. Therefore, to our knowledge, for the first time, we demonstrated the generation of footprint-free and high-quality ciPSCs that can be passaged at the single-cell stage using enzymatic methods. Our method for generation of ciPSCs is a good step toward the development of clinical application of ciPSCs.