Pigs are important for disease model generation, xenotransplantation, and interspecies organogenesis. Porcine induced pluripotent stem cells (piPSCs) should enable these efforts, but have not been generated to meet the attributes, such as feeder-free culture, robust development potential, and blastocyst generation through nuclear transfer. We report an improved strategy to generate such piPSCs. We show that chemically defined medium 3 promotes the formation of epithelium-like colonies in porcine reprogramming, which allows further reprogramming under the new medium cocktail LACID. The resulting piPSCs have key features, including flat morphology with feeder-free culture, generating robust teratoma and blastoids, forming chimeric blastocysts, and readily edited with CRISPR-Cas9. Lastly, nuclear transfer with piPSCs can develop into blastocysts. Despite maintaining a primed pluripotent state, our results suggest that the newly established LACID piPSCs may be ideal for applications in regenerative medicine. This method may be further improved to generate naive or totipotent stem cells.
Shi et al. (Sun,) studied this question.