BMP4 plays a role in apoptosis during human preimplantation development

Comprehensive understanding of lineage differentiation and apoptosis processes is important to increase our knowledge of human preimplantation development in vitro. We know that BMP signaling is important for different processes during mammalian development. In mouse preimplantation embryos, BMP signaling has been shown to play a role in the differentiation into extra-embryonic trophectoderm (TE) and primitive endoderm (PE). In this study, we aimed to investigate the effect of bone morphogenetic protein 4 (BMP4) supplementation on human preimplantation embryos cultured in vitro. The BMP4 treatment impaired human blastocyst formation. No differences in the expression of the early lineage markers NANOG, CDX2, GATA3, and GATA6 were found between BMP4-treated embryos and controls. Instead, BMP4 supplementation triggered apoptosis in the human blastocyst. We focused on P53, which is known to play a major role in the apoptosis. In BMP4-treated embryos, the P53 responsive gene expression was not altered; however, the P53 deacetylase SIRT1 was downregulated and acetylated P53 was increased in mitochondria. Altogether, our findings suggest that BMP4 plays a role in the apoptosis during human preimplantation development.