Early life infection alters adult BALB/c hippocampal gene expression in a sex specific manner.

During the perinatal period, the developing brain is sensitive to environmental events. Deleterious programing resulting from infection, dietary restriction, or psychological stress has been observed and affects adult immune and endocrine systems as well as behavior. In this study, we determined whether neonatal infection permanently alters immune and glucocorticoid receptor signaling pathways in the adult hippocampus. A Chlamydia muridarum respiratory infection was induced in male and female mice at birth. Mice were allowed to recover and microarray analysis was conducted on RNA from adult hippocampal tissue. In males, neonatal infection induced an up-regulation of genes associated with cellular development, nervous system development and function, such as cyclin-dependent kinase inhibitor 1A. After neonatal infection, adult females exhibited a T-helper 2 immune bias with genes such as major histocompatibility complex, class II, DQ beta 1 up-regulated. Expression of prolactin, vasopressin, hypocretin, corticotrophin-releasing hormone-binding protein, and oxytocin were confirmed by quantitative real-time polymerase chain reaction. This study shows that neonatal infection differentially alters the gene expression profiles of both female and male mice along immune and neuroendocrine pathways.