RNA Sendai virus (SeV) vector system has no risk of being integrated into the host genome. Sendai virus (SeV) vectors expressing pluripotent factors have been used to produce integration-free induced pluripotent stem cells (iPSCs) with high efficiency from various cell types in human and mouse. In this study, we generated iPSCs from pig ear fibroblast cells using the SeV vector expressing 4 human factors (POU5F1, SOX2, C-MYC, and KLF4). Colonies were emerged at Day 14 of transduction and expressed the classical pluripotency markers (POU5F1, NANOG, and SOX2) and surface marker (SSEA1). Furthermore, they showed a domed shape and could passage over 40 times under 2i (CHIR99021 and PD0325901)-LIF and MEF feeder culture condition having in vitro differentiation ability into 3 germ layers. Next, we examined the ability of six feeder free culture conditions to maintain piPSCs in a pluripotent state. piPSCs were plated on Matrigel coated dishes in different media: 1. CM: control media (LIF culture media); 2. CM-F: CM+100 ng Fetuin-A; 3. CM-N: CM+100 ng Nanog-TAT; 4. CM-2i: CM+3 uM CHIR99021+1 uM PD0325901; 5. CM-2iN: CM-2i+100 ng Nanog-TAT; 6. CM-2iN+100 ng Fetuin-A. However, piPSC could not maintain the typical self-renewal morphology on feeder free conditions regardless of culture media tested here. Further, expression of pluripotency-related genes (Oct4, Nanog and Klf4) of piPSCs cultured on feeder free conditions could not be compared with that of iPSCs cultured on MEF feeder plate. Our results suggest that integration free pluripotent stem cell from pigs could be generated by SeV vector system and maintained their pluripotency under 2i-LIF and MEF feeder culture condition, but further optimization of culture conditions may be required.

Human embryonic stem cells (hESCs) have been routinely cultured on mouse embryonic fibroblast feeder layers with a medium containing animal materials. For clinical application of hESCs, animal-derived products from the animal feeder cells, animal substrates such as gelatin or Matrigel and animal serum are strictly to be eliminated in the culture system. In this study, we performed that SNUhES32 and H1 were cultured on human amniotic fluid cells (hAFCs) with KOSR XenoFree and a humanized substrate. All of hESCs were relatively well propagated on hAFCs feeders with xeno-free conditions and they expressed pluripotent stem cell markers, alkaline phosphatase, SSEA-4, TRA1-60, TRA1-81, Oct-4, and Nanog like hESCs cultured on STO or human foreskin fibroblast feeders. In addition, we observed the expression of nonhuman N-glycolylneuraminic acid (Neu5GC) molecules by flow cytometry, which was xenotransplantation components of contamination in hESCs cultured on animal feeder conditions, was not detected in this xeno-free condition. In conclusion, SNUhES32 and H1 could be maintained on hAFCs for humanized culture conditions, therefore, we suggested that new xenofree conditions for clinical grade hESCs culture will be useful data in future clinical studies.