Dynamic DNA methylation programs persistent adverse effects of early-life stress

Area of Science:

• Neuroscience
• Epigenetics
• Endocrinology

Background:

• Adverse early life events can lead to persistent physiological and behavioral changes.
• Early-life stress (ELS) is linked to altered stress responses and cognitive deficits.

Purpose of the Study:

• To investigate the molecular mechanisms underlying long-lasting effects of ELS on neuroendocrine and behavioral outcomes.
• To explore the role of arginine vasopressin (AVP) and DNA methylation in mediating ELS-induced phenotypes.

Main Methods:

• Mice were subjected to ELS, and subsequent physiological and behavioral assessments were performed.
• Arginine vasopressin (AVP) expression in the hypothalamus was measured.
• DNA methylation patterns in regulatory regions of the Avp gene were analyzed.
• The effect of an AVP receptor antagonist on ELS-induced phenotypes was evaluated.

Main Results:

• ELS induced persistent hypersecretion of corticosterone and altered stress coping and memory in mice.
• A sustained increase in hypothalamic AVP expression was observed post-ELS.
• This AVP alteration was linked to stable DNA hypomethylation in an Avp gene regulatory region, involving MeCP2 binding sites.
• Pharmacological blockade of AVP receptors reversed the ELS-induced phenotype.

Conclusions:

• ELS can induce stable epigenetic modifications in neuronal DNA methylation, specifically affecting the Avp gene.
• These epigenetic changes contribute to long-term neuroendocrine and behavioral alterations relevant to depression.
• Neuronal activity plays a critical role in regulating activity-dependent gene transcription and epigenetic marking of the Avp gene.