Cellular reprogramming by single-cell fusion with mouse embryonic stem cells in pig.

Fusion of differentiated somatic cells with pluripotent stem cells can be used for cellular reprogramming, but the efficiency to obtain hybrid cells is extremely low. Here, we explored a novel cell fusion system, termed single-cell fusion, the efficiency was significantly improved verified by fusion of mouse embryonic stem cells (mESCs), comparing to traditional polyethylene glycol fusion. Then, we employed the optimized system to perform cell fusion of porcine embryonic fibroblasts (PEFs) and porcine pluripotent stem cells (pPSCs) with mESCs. The hybrid cells showed both red and green fluorescence and expressed species-specific genes of mouse and pig to evidence that the fusion was successful. The hybrid cells displayed characteristics similar with mESCs, including colony morphology, alkaline phosphatase positive and formation of embryoid body, and the expressions of core pluripotent factors OCT4, NANOG, and SOX2 of the pig were induced in the mESC/PEF hybrid cells. The results indicate PEFs and pPSCs could be reprogrammed by mESCs via the single-cell fusion. Taking advantage of the hybrid cells to investigate the signaling pathways depended on the pluripotency of pig, we suggest the transforming growth factor-β signaling pathways may play important roles. In summary, the single-cell fusion is highly efficient, and we believe in the future it will be widely used in the application and fundamental research.