Placental effects on the maternal brain revealed by disrupted placental gene expression in mouse hybrids.

The mammalian placenta is both the physical interface between mother and fetus, and the source of endocrine signals that target the maternal hypothalamus, priming females for parturition, lactation and motherhood. Despite the importance of this connection, the effects of altered placental signalling on the maternal brain are insufficiently studied. Here, we show that placental dysfunction alters gene expression in the maternal brain, with the potential to affect maternal behaviour. Using a cross between the house mouse and the Algerian mouse, in which hybrid placental development is abnormal, we sequenced late-gestation placental and maternal medial preoptic area transcriptomes and quantified differential expression and placenta-maternal brain co-expression between normal and hybrid pregnancies. The expression of Fmn1 and Drd3 was significantly altered in the brains of females exposed to hybrid placentas. Most strikingly, expression patterns of placenta-specific gene families and Drd3 in the brains of house mouse females carrying hybrid litters matched those of female Algerian mice, the paternal species in the cross. Our results indicate that the paternally derived placental genome can influence the expression of maternal-fetal communication genes, including placental hormones, suggesting an effect of the offspring's father on the mother's brain.