Contrasting Effects of Different Maternal Diets on Sexually Dimorphic Gene Expression in the Murine Placenta

Diet during pregnancy influences the future health of a woman's offspring, with outcomes differing depending on the child's sex. Because the placenta buffers the fetus from the mother, we examined the impact of diet and fetal sex on placental gene expression in mice fed either a very-high-fat, low-fat, chow diet of intermediate caloric density. At day 12.5 of pregnancy, placental RNA was extracted and analyzed by microarray. The expression of 1,972 genes was changed more than 2-fold (P < 0.05) in comparisons across diet in at least one of the three groups. Female placentae demonstrated more striking alterations in gene expression in response to maternal diet than male placentae. Notably, each diet provided a distinctive signature of sexually dimorphic genes, with expression generally higher in genes (651 out of 700) from female placentae than those from male placentae. Several genes normally considered as characteristic of kidney function were affected by diet, including genes regulating ion balance and chemoreception. The placenta also expressed most of the known olfactory receptor genes (Olfr), which may allow the placenta to sense odorant molecules and other minor dietary components, with transcript levels of many of these genes influenced by diet and fetal sex. In conclusion, gene expression in the murine placenta is adaptive and shaped by maternal diet. It also exhibits pronounced sexual dimorphism, with placentae of females more sensitive to nutritional perturbations than placentae of males.