Social stress increases expression of hemoglobin genes in mouse prefrontal cortex

Background: In order to better understand the effects of social stress on the prefrontal cortex, we investigated gene expression in mice subjected to acute and repeated social encounters of different duration using microarrays. Results: The most important finding was identification of hemoglobin genes (Hbb-b1, Hbb-b2, Hba-a1, Hba-a2, Beta-S) as potential markers of chronic social stress in mice. Expression of these genes was progressively increased in animals subjected to 8 and 13 days of repeated stress and was correlated with altered expression of Mgp (Mglap), Fbln1, 1500015O10Rik (Ecrg4), SLC16A10, and Mndal. Chronic stress increased also expression of Timp1 and Ppbp that are involved in reaction to vascular injury. Acute stress did not affect expression of hemoglobin genes but it altered expression of Fam107a (Drr1) and Agxt2l1 (Etnppl) that have been implicated in psychiatric diseases. Conclusions: The observed up-regulation of genes associated with vascular system and brain injury suggests that stressful social encounters may affect brain function through the stress-induced dysfunction of the vascular system.