title: Developmental timing of the effects of maternal care on gene expression and epigenetic regulation of hormone receptor levels in female rats.
abstract: Maternal care experienced during postnatal development has enduring effects on neuroendocrine function and behavior. Previous studies in rats have illustrated the effect of maternal licking/grooming (LG) on hormone receptors and maternal behavior of adult female offspring associated with altered DNA methylation. However, the developmental timing of these effects, which provide insight into the cellular and molecular pathways through which early experience alters later behavior, had not been explored. Here, we demonstrate the developmental emergence of these outcomes and use cross-fostering to identify sensitive periods for these effects. Estrogen receptor (ER)α and ERβ mRNA levels within the medial preoptic area (MPOA) of the hypothalamus were increased by postnatal day (PN)21 in female offspring of high LG dams; LG-associated increases in oxytocin receptor mRNA levels were observed beyond the weaning period. Quantification of ERα-immunoreactivity indicated a high degree of neuroanatomical specificity of LG effects within the MPOA that were observed by PN6. Reduced DNA methylation and histone 3 lysine 9 tri-methylation and increased histone 3 lysine 4 tri-methylation at the ERα gene promoter (Esr1) were detected at PN21 in high LG female offspring. Latency to engage in maternal behavior toward donor pups was significantly shorter among high LG females. Cross-fostering revealed that maternal sensitization and MPOA ERα levels are sensitive to maternal care experienced before but not after PN10. Differential windows of plasticity were identified for ERβ and oxytocin receptor mRNA levels. These studies contribute significantly to our understanding of the molecular, neurobiological, and behavioral pathways through which variation in maternal behavior is transmitted from one generation to the next.
authors.affiliation: Department of Psychology, Columbia University, 406 Schermerhorn Hall, 1190 Amsterdam Avenue, New York, New York 10027. fac2105@columbia.edu.
authors.forename: Catherine Jensen
authors.initials: CJ
authors.lastname: Peña
authors.forename: Y Dana
authors.initials: YD
authors.lastname: Neugut
authors.forename: Frances A
authors.initials: FA
authors.lastname: Champagne
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D019175:DNA Methylation; D044127:Epigenesis, Genetic / Q000502:physiology*; D047628:Estrogen Receptor alpha / Q000235:genetics / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000235:genetics / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D007031:Hypothalamus; D008425:Maternal Behavior / Q000502:physiology*; D051381:Rats; D020332:Rats, Inbred LEC; D018045:Receptors, Oxytocin / Q000235:genetics / Q000378:metabolism; D011987:Receptors, Steroid / Q000235:genetics / Q000378:metabolism*; D012741:Sexual Maturation
chemical_list: D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D018045:Receptors, Oxytocin; D011987:Receptors, Steroid