Benzo(a)pyrene causes PRKAA1/2-dependent ID2 loss in trophoblast stem cells.

Benzo(a)pyrene (BaP), a cigarette smoke component, is metabolized to diol esters (BPDE) that bind to DNA and form mutagenic BPDE-DNA adducts. BaP activates stress enzymes including stress-activated protein kinase/jun kinase (MAPK8/9) in embryos, AMP-activated protein kinase alpha1/2 subunits (PRKAA1/2) in somatic cells, and inhibits the proliferation of trophoblast cell lineages. The loss of transcription factor inhibitor of differentiation (ID)2 is required for the initial differentiation of mouse trophoblast stem cells (TSC) in implanting mouse embryo to produce the first placental hormone, chorionic sommatomammotropin (CSH)1.