PROJECT SUMMARY This is a proposal to facilitate prospective collection of a sample of women at risk for postpartum depression (PPD) in order to facilitate the validation and refinement of epigenetic biomarkers predictive of the disease. Funds obtained will be used to enable genome-wide genetic and epigenetic analysis of subjects recruited under the BRAINS R01 mechanism. The project will take advantage of the talents of a leader in the field of women's mental health and PPD and a highly experienced DNA methylome researcher. The precipitation of anxiety and depressive symptoms in PPD is thought to be triggered by the rapid withdrawal of gonadal hormones. Evidence out of our laboratory and others implicate a heightened sensitivity of at-risk women to fluctuation in estradiol (E2), specifically on the level of DNA methylation. The central hypothesis that PPD risk may arise due to an altered sensitivity of the epigenetic reprogramming machinery in response to gonadal hormones and that epigenetic markers of PPD resultant from pregnancy related hormonal changes will be detectable in blood. In previous work, we used DNA methylation modeled on hippocampal E2 responsiveness and identified successful epigenetic predictors of human PPD from antenatal blood at the HP1BP3 and TTC9B genes that exhibit >82% accuracy at predicting PPD. In Aim 1, we propose to expand collection of blood and psychological measures from 100 pregnant women with a history of mood disorders and 200 pregnant women from the general population beyond that afforded by the BRAINS R01. Collection will take place within the 1st, 2nd, and within 2 and 6 weeks postpartum in all but 80 women selected for the BRAINS protocol. For all women, we will extend the data collection period by adding a 3 month time point. In Aim 2, genome-wide Illumina HM450 methylation chips will be used to validate existing PPD biomarker efficacy and refine and add to novel biomarker models. In Aim 3, a longitudinal analysis of microarray signatures will be performed and integrated with genetic and hormonal data to understand methylation changes resultant from parturition and potential precipitating PPD episodes. Pyrosequencing will be used to assess promising loci identified in Aims 2 and 3 across all prospective time points. In Aim 4, genome-wide data will be integrated with neuroimaging endophenotypes in the N=80 women who underwent the BRAINS prospective fMRI imaging protocol. Promising loci will be followed up in in vitro cell culture models to assess for causative roles in models of synaptic plasticity. This study will generate an important PPD resource, confirm and expand the utility of early screening, and identify new targets and time points for therapeutic intervention.