Pdx1 protein induces human embryonic stem cells into the pancreatic endocrine lineage

Success in generating insulin-producing cells (IPCs) from human embryonic stem (hES) cells by genetic manipulation has recently revealed a new therapeutic potential for diabetes. However, clinical application has been hampered by the viral genome integration and the risk of insertion mutagenesis that are entailed. Herein, we report the induction of hEC into IPCs by direct delivery of human Pdx1 proteins per se. Recombinant human Pdx1 proteins (hPdx1), which have an Antennapedia-like protein transduction domain sequence in their structure, can be efficiently translocated into hES cells and function as pancreatic transcription factor. hPdx1 protein activates a group of genes related to pancreatic beta-cell lineage development in hES cells, including NeuroD1, Nkx2.2, Pax4, Pax6, Nkx6.1 and Isl-1. hPdx1-treated hES cells synthesise and release insulin in response to glucose challenge. Therefore, this study constitutes a proof-of-concept demonstration of protein-mediated pancreatic specific differentiation of the hES cells by exploiting specific intrinsic properties of the hPdx1 protein.