Murgatroyd, C. | Search bioRxiv

bioRxiv2018

Discrimination Exposure and DNA Methylation of Stress-Related Genes in Latina Mothers

Latina mothers, who have the highest fertility rate among all ethnic groups in the US, are often exposed to discrimination. The biological impacts of this discrimination are unknown. This study is the first to explore the relationship between discrimination and DNA methylation of stress regulatory genes in Latinas. Our sample was Latina women (n = 147) with a mean age of 27.6 years who were assessed at 24-32 weeks gestation (T1) and 4-6 weeks postpartum (T2) and reside in the U.S. Blood was collected at T1, and the Everyday Discrimination Scale (EDS) was administered at T1 and T2. DNA Methylation at candidate gene regions was determined by bisulphite pyrosequencing. Associations between EDS and DNA methylation were assessed via zero-inflated Poisson models, adjusting for covariates and multiple-test comparisons. Discrimination was negatively associated with methylation at CpG sites within the glucocorticoid receptor (NR3C1) and brain-derived neurotrophic factor (BDNF) genes that were consistent over time. In addition, discrimination was negatively associated with methylation of a CpG in the glucocorticoid binding protein (FKBP5) at T1 but not at T2. This study underscores the complex biological pathways between discrimination and epigenetic modification in Latina women that warrant further investigation to better understand the genetic and psychopathological impact of discrimination on Latino mothers and their families.

genomics↗

bioRxiv2017

Maternal depression and child behaviours: sex-dependent mediation by glucocorticoid receptor gene methylation in a longitudinal study from pregnancy to age 5 years

BackgroundEvolutionary hypotheses predict that male fetuses are more vulnerable to poor maternal conditions than females (Sex-biased Maternal Investment), but that the adaptive female fetus, with a more responsive hypothalamic-pituitary-adrenal (HPA) axis, is put at later risk of glucocorticoid mediated disorders where there is a mismatch between fetal and postnatal environments (Predictive Adaptive Response). Self-report measures of prenatal and postnatal depression and maternal report of child anxious depressed symptoms at 2.5, 3.5 and 5.0 years were obtained from an extensive sample of first time mothers recruited from the general population (N = 794). Salivary NR3C1 1-F promoter methylation was assayed at 14 months in an intensive subsample (N = 176) stratified during pregnancy by psychosocial risk. Generalised structural equation models (SEM) were fitted and estimated by maximum likelihood to allow inclusion of participants from both intensive and extensive samples.\n\nResultsPostnatal depression was associated with NR3C1 methylation and with anxious-depressed symptoms in the daughters of mothers lacking the hypothesised protective effect of high prenatal depression (prenatal-postnatal depression interaction for methylation, p =.00001; for child symptoms, p = .011). In girls, NR3C1 methylation mediated the association between maternal depression and child anxious-depressed symptoms. The effects were greater in girls than boys, and the test of the sex differences in the effect of the prenatal-postnatal depression interaction on both outcomes gave {chi}2(2) = 5.95 (p=.051).\n\nConclusionsThis is the first study to show in humans that, as a result of sex-biased reproductive investment and fetal adaptation, epigenetic and early behavioural outcomes may arise through different mechanisms in males and females. Epigenetic effects at the NR3C1 promoter mediated mismatch between prenatal and postnatal maternal conditions and child anxious-depressed symptoms, specifically in females.

genetics↗