Transcriptomic Profiling of Porcine Pluripotency Identifies Species-specific Reprogramming Requirements for Culturing iPSCs

Abstract Porcine embryonic and induced pluripotent stem cells (ESCs; iPSCs) have proven difficult to derive and maintain in vitro. This may be due to inappropriate culturing conditions and incomplete activation of proper pluripotency networks. To this end, we characterized the transcriptome of porcine inner cell mass, epiblast, and transgene-dependent iPSCs in relation to human and mouse embryonic and epiblast stem cells. We found that porcine inner cell mass have a unique pluripotency transcriptome distinct from human and mouse ESCs but shares more features with human naive-like than primed stem cell states, as illustrated by their expression of KLF17 but not KLF2. Our data further shows that current reprogramming strategies fail to silence parental fibroblast-specific genes and to activate specific signalling pathways that may be important for porcine pluripotency. Accordingly, we used human naive culturing conditions to improve reprogramming efficiencies of porcine embryonic fibroblasts and enable essential naive stem cell markers to be expressed such as NANOG, KLF17 and CDH1. The resultant porcine iPSC-like cells display a transcriptomic signature more closely resembling an inner cell mass state. These results represent new important steps towards generating bona fide porcine iPSCs and their great potential in translational medicine.