Sex-Dependent Differences in Mouse Placental Gene Expression following a Maternal High-Fat Diet

Objective In utero fetal exposures may have sex-specific placental gene responses. Our objective was to measure sex-based differences in placental gene expression from dams fed high-fat diet (HFD) versus control diet (CD). Study Design We fed timed pregnant Friend virus B–strain dams either a CD (n = 5) or an HFD (n = 5). We euthanized dams on embryonic day 17.5 to collect placentas. We extracted placental RNA and hybridized it to a customized 96-gene Nanostring panel focusing on angiogenic, inflammatory, and growth genes. We compared normalized gene expression between CD and HFD, stratified by fetal sex, using analysis of variance. Pathway analysis was used to further interpret the genomic data. Results Pups from HFD-fed dams were heavier than those from CD-fed dams (0.97 ± 0.06 vs 0.84 ± 0.08 g, p < 0.001). Male pups were heavier than females in the HFD (0.99 ± 0.05 vs 0.94 ± 0.06 g, p = 0.004) but not CD (0.87 ± 0.08 vs 0.83 ± 0.07 g, p = 0.10) group. No sex-based differences in placental gene expression in CD-fed dams were observed. Among HFD-fed dams, placentas from female pups exhibited upregulation of 15 genes (q = 0.01). Network analyses identified a cluster of genes involved in carbohydrate metabolism, cellular function and maintenance, and endocrine system development and function (p = 1 × 10−23). The observed female-specific increased gene expression following in utero HFD exposure was predicted to be regulated by insulin (p = 5.79 × 10−13). Conclusion In female compared with male pups, in utero exposure to HFD upregulated placental gene expression in 15 genes predicted to be regulated by insulin. Sex-specific differences in placental expression of these genes should be further investigated. Key Points