Transcriptional Signatures of Cognitive Impairment in Rat Exposed to Prenatal Stress

Exposure to adverse events during gestation has detrimental effects on the maturation of specific brain networks, triggering changes in the expression of several stress-related mechanisms that may lead to long-lasting functional consequences, including cognitive deterioration. On these bases, the aim of the present study was to investigate the effects of early-life stress exposure on cognition and to explore potential molecular mechanisms contributing to the long-term functional impairment. We found that exposure to prenatal stress, a well-established animal model of early-life adversity, produces a significant disruption in the novel object recognition test both in male and female adult rats, although such impairment was more pronounced in females. Furthermore, the cognitive dysfunction observed during the behavioral test appears to be sustained by a disrupted activation of key networks of genes that may be required for proper cognitive performance. In particular, within the dorsal hippocampus, a brain region critical for cognition, the glucocorticoid, the inflammatory, and the protein kinase A signaling pathways are regulated by the novel object recognition test in an opposite manner in animals previously exposed to prenatal stress, when compared with control animals. These data further support the evidence that early-life stress exposure prompts cognitive impairment and suggest that this is the consequence of inability to activate the proper transcriptional machinery required for the cognitive performance.