Gatekeeper transcription factors regulate switch between lineage preservation and cell plasticity

Reprogramming somatic cells to pluripotency by repressing lineage-instructive transcription factors (TFs) alone has not been pursued because lineage specification is thought to be regulated by transcriptional regulatory networks (TRNs) comprising of multiple TFs rather than by single pivotal "gatekeeper" TFs. Utilizing an intra-species somatic cell hybrid model, we identified Snai2 and Prrx1 as the most critical determinants of mesenchymal commitment in rat embryonic fibroblasts (REFs) and demonstrate that siRNA-mediated knockdown of either of these master regulators is adequate to convert REFs into functional adipocytes, chondrocytes or osteocytes without requiring exogenous TFs or small molecule cocktails. Furthermore, knockdown of Snai2 alone proved sufficient to transform REFs to dedifferentiated pluripotent stem-like cells (dPSCs) that formed embryoid bodies capable of triple germ-layer differentiation. These findings suggest that inhibition of a single gatekeeper TF in a lineage committed cell is adequate for acquisition of cell plasticity and reprogramming without requiring permanent genetic modification. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=143 SRC="FIGDIR/small/999433v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@1acdb83org.highwire.dtl.DTLVardef@17fb3ddorg.highwire.dtl.DTLVardef@f994c9org.highwire.dtl.DTLVardef@197541e_HPS_FORMAT_FIGEXP M_FIG C_FIG Schematic diagram depicting transdifferentiation of REFs into adipocytes, osteocytes, chondrocytes and dedifferentiation into MSCs on individual treatment with siSnai2 or siPrrx1. dPSCs were generated only in the siSnai2 group.