Impact of social defeat stress on DNA methylation in Drd2, Nr3c1, and Stmn1 in wild-type and Stmn1 knock-out mice

Young-Eun Oh ^{1, 2}, Thong Ba Nguyen ^{1, 2}, Fatima Zahra Rami ^{1, 2}, Maryam Karamikheirabad ^{1, 2}, Young-Chul Chung ^{1, 2*}

¹Department of Psychiatry, Jeonbuk National University Medical School, Jeonju, Korea, ²Research Institute of Clinical Medicine of Jeonbuk National University, Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Korea

Received: September 8, 2020; Revised: October 26, 2020; Accepted: October 27, 2020; Published online: October 27, 2020.

Abstract: Objective: Epigenetic profiles can be modified by stress. Dopamine receptor D2 glucocorticoid receptor gene and Stathmin 1 genes are all implicated in adaptation to stress. The aim of study is to investigate impact of social defeat on DNA methylation in Drd2, Nr3c1 and Stmn1 in wild-type and Stmn1 knock-out mice.
Methods: The WT and Stmn1 KO mice were subjected to chronic social defeat. Brain tissues of the prefrontal cortex, amygdala and hippocampus were obtained. We measured DNA methylation levels of the Drd2, Nr3c1 and Stmn1 genes in the PFC, AMY and HIP using pyrosequencing.
Results: In WT mice, social defeat stress did not induce any changes in Drd2 methylation, whereas significant hypermethylation occurred in Nr3c1 and Stmn1 in the susceptible and unsusceptible groups, respectively, compared to the control group. The methylation responses in the Stmn1 KO mice differed from those seen in the WT mice, such that hypermethylation was evident in all three genes in the susceptible and unsusceptible groups compared to control group.
Conclusions: Social defeat stress induced different epigenetic modifications in three genes among control, unsusceptible, and susceptible groups of WT and Stmn1 KO mice. In particular, hypermethylation of Nr3c1 in the HIP of the susceptible group, and of Stmn1 in the AMY of the unsusceptible group in WT mice, could serve as epigenetic biomarkers of stress susceptibility and stress resilience, respectively.
Keywords: Social defeat stress, DNA methylation, Dopamine receptor D2 (Drd2), Nr3c1, Stathmin 1, Epigenetic.; Keywords: Social defeat stress, Nr3c1, DNA methylation, Stathmin 1, Dopamine receptor D2 (Drd2), Epigenetic

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