Molecular and Behavioral Effects of Infant Maltreatment across Generations in Rhesus Monkeys

Childhood maltreatment is among the most robust risk factors for subsequent psychiatric and medical disorders, and data in humans and rodents suggest that effects of adverse childhood experiences may be transmitted across generations. Recent indications for biological processes underlying this transfer of experiential effects are intriguing; yet, their relevance in primates is inconclusive due to limitations of current studies. In this study, we bridge research in rodent models and humans with a natural non-human primate model on intergenerational effects of childhood maltreatment. Using a unique, well-controlled, randomized cross-fostering design in rhesus monkeys, we test the influence of ancestral maltreatment on molecular, neuroendocrine and behavioral outcomes in offspring, and show that childhood maltreatment results in transmission of information to the subsequent generation independent of behavioral transmission. We further demonstrate differences in the offspring longitudinal DNA methylation profile of the FKBP5 gene, an important regulator of the hypothalamus-pituitary-adrenal axis in offspring of the maltreatment lineage compared to the control lineage. Finally, we show that differences in FKBP5 methylation have functional effects on molecular, neuroendocrine and behavioral outcomes in offspring of the maltreatment ancestral line, even if the infants were never exposed to maltreatment nor interacted with their exposed ancestors. Although the molecular mechanism underlying our observations remains unknown, our data point to a potential germline-dependent effect. In summary, our data suggest that history of maltreatment in primates can induce molecular and behavioral changes in a subsequent generation independent of behavioral transmission that may influence risk for mental and physical diseases across generations.