摘要

Porcine induced pluripotent stem cells (piPSCs) retain the enormous potential for farm animal reproduction and translational medicine, and have been reported by many laboratories worldwide. Some piPSC lines were bFGF-dependence and showed mouse EpiSC-like morphology; other lines were LIF-dependence and showed mouse ESC-like morphology. Metastable state of piPSC line that required both LIF and bFGF was also reported. Because bona fide pig embryonic stem cells were not available, uncovering piPSC state-specific regulatory circuitries was the most important task. In this study, we explored the function of Activin-SMAD signaling pathway and its downstream activated target genes in piPSCs. Transcriptome analysis showed that genes involved in Activin-SMAD signaling pathway were evidently activated during porcine somatic cell reprogramming, regardless piPSCs were LIF- or bFGF-dependent. Addition of Activin A and overexpression of SMAD2/3 significantly promoted expressions of porcine NANOG and OCT4, whereas inhibition of Activin-SMAD signaling by SB431542 and SMAD7 reduced NANOG and OCT4 expressions, and induced piPSCs differentiation exiting from pluripotent state. Our data demonstrate that activation of Activin-SMAD signaling pathway by addition of Activin A in culture medium is necessary for maintenance of self-renewal in porcine pluripotent stem cells.