Sex differences in the molecular signature of the developing mouse hippocampus

A variety of neurological disorders, including Alzheimer's disease, Parkinson's disease, major depressive disorder, dyslexia and autism, are differentially prevalent between females and males. To better understand the possible molecular basis for the sex-biased nature of neurological disorders, we measured both mRNA and protein in the hippocampus of female and male mice at 1, 2, and 4 months of age with RNA-sequencing and mass-spectrometry respectively. Differential expression analyses identify 2699 genes that are differentially expressed between animals of different ages. 198 transcripts are differentially expressed between females and males at one or more ages. The number of transcripts that are differentially expressed between females and males is greater in adult animals than in younger animals. Additionally, we identify 69 transcripts that show complex and sex-specific patterns of temporal regulation across all ages, 8 of which are heat-shock proteins. We also find a modest correlation between levels of mRNA and protein in the mouse hippocampus (Rho = 0.53). This study adds to the substantial body of evidence for transcriptomic regulation in the hippocampus during postnatal development. Additionally, this analysis reveals sex differences in the transcriptome of the developing mouse hippocampus, and further clarifies the need to include both female and male mice in longitudinal studies involving molecular changes in the hippocampus. Overall design: Hippocampal mRNA from 1, 2, and 4 month old male and female B6 mice were analyzed by RNA sequencing of 5 biological replicates using an Illumina HiSeq 2500

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Bundy JL, Vied C, Nowakowski RS