Specificity protein 6 governs human cytotrophoblast fate decisions and trophoblast stem cell establishment by targeting MSX2 regulatory elements [ChIP-seq]

The commitment and differentiation of human placental progenitor cytotrophoblast (CT) cells are crucial for a successful pregnancy, but the underlying regulatory mechanism remains poorly understood. Here we identified the transcription factor (TF), Specificity protein 6 (SP6), as a human species-specific trophoblast lineage TF expressed in human placental CT cells. Using pluripotent stem cells as a model, we demonstrated that SP6 governs CT generation and the establishment of trophoblast stem cells (TSCs) and discovered msh homeobox 2 (MSX2) as the downstream effector in these events. Mechanistically, we showed that SP6 interacts with histone acetyltransferase P300 to modulate the landscape of H3K27ac at targeted regulatory elements, thereby favoring transcriptional activation and facilitating CT cell fate decisions and TSC maintenance. Our results established SP6 as a novel regulator of the human trophoblast lineage and implied its regulatory role in placental development and the pathogenies of placental diseases.