Human PGC commitment shares key gene dynamics to mouse, but owns a unique PRDM14 expression pattern

The molecular mechanisms of human primordial germ cell (PGC) specification are poorly understood due to the inaccessibility of cell materials and the lack of an alternative in vitro model that enables tracking of the earliest stages of germ cell development. Here, we introduce a defined and efficient differentiation system for the induction of pre-migratory PGC-like cells from human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). By step-wise differentiation, we generated an OCT4+/ T+/BLIMP1+ cell population that transitioned into STELLA expressing PGC-like cells that exhibited a similar key gene expression as mouse PGCs as well as global epigenetic reprogramming. Even though, these PGC-like cells expressed PRDM14 at very low levels, they underwent activation of pluripotency/PGC genes, suppression of neural induction and suppression of de novo DNA methylation, events that are regulated by Prdm14 during mouse PGC specification. This study demonstrates that human PGC commitment shares many key features with mouse PGC specification, but harbors unique and so far unknown mechanisms that, point to a novel human transcriptional regulation. 7 samples were analyzed. ESC: Human Embryonic Stem Cells, 1 biological rep iPSC: Human induced Pluripotent Stem Cells, 1 biological rep d2: Human induced Pluripotent Stem Cells, 2 days differentiation treatment , 2 biological rep d4PGCLC: Human induced Pluripotent Stem Cells, 4 days differentiation treatment towards Primordial Germ Cells Like Cells, 1 biological rep d6PGCLC: Human induced Pluripotent Stem Cells, 6 days differentiation treatment towards Primordial Germ Cells Like Cells, 2 biological rep