Vascular endothelial growth factor (VEGF) is implicated as a molecular mediator for adult neurogenesis and behavioral effects of antidepressant drugs. However, these potential roles of VEGF in the CNS have not been clarified in model animals. Here we have created transgenic mice overexpressing a short active variant of VEGF-A (VEGF120) in forebrain. Expression of VEGF120 significantly enhanced cell proliferation and angiogenesis, as exemplified by the formation of an enlarged reddish brain. Adult neurogenesis in hippocampus was markedly stimulated without affecting cell differentiation of neural progenitor cells. Hippocampal neurogenesis was particularly robust in young adult animals, but it declined with age and reduced to control levels by 20 weeks under continuous expression of VEGF120. Thus, VEGF alone is not sufficient to support the long-term enhancement of adult neurogenesis, and VEGF-induced vascularization per se does not necessarily predict increased neurogenesis. In transgenic mice, we observed significant changes in affective behaviors. VEGF was found to have not only antidepressant effects but also anxiolytic effects. In addition, we found that VEGF significantly reduced fear and aggression. In contrast, basal activities under natural conditions were not affected much. Unexpectedly, these characteristic behaviors were maintained in older transgenic mice undergoing a reduced level of cell proliferation in hippocampus, suggesting that there is potential dissociation between adult neurogenesis and mood regulation. Our data indicate that VEGF exerts strong neurogenic and angiogenic effects in postnatal brain and influences different forms of affective behaviors.

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Recent increases in fructose consumption have raised concerns about the potential adverse intergenerational effects of excess fructose intake. In the present study, we investigated whether excess maternal fructose intake affects hippocampal function in offspring. Female Sprague-Dawley rats were divided into 3 experimental groups: one group received distilled water, one group received 20% fructose water, and one group received 20% glucose water in addition to standard chow during gestation and lactation. Hippocampal function of offspring was evaluated by using novel object recognition and fear conditioning tests. Impaired cognitive performance was observed in the offspring of fructose-fed dams at postnatal d 60, potentially a result of decreased hippocampal neurogenesis. Real-time PCR analysis demonstrated that offspring from fructose-fed dams exhibited decreased brain-derived neurotrophic factor ( BDNF) gene expression, whereas pyrosequencing assays revealed increased DNA methylation at the BDNF promoter. The potential association between BDNF transcription and levels of DNA methylation was confirmed on the basis of luciferase activity. Furthermore, longitudinal analysis revealed that increased methylation of the BDNF promoter region was maintained at least until rats reached maturity. These results indicate that epigenetic changes associated with BDNF may underlie hippocampal dysfunction that is induced by early-life exposure to excess maternal fructose consumption.-Yamazaki, M., Yamada, H., Munetsuna, E., Ishikawa, H., Mizuno, G., Mukuda, T., Mouri, A., Nabeshima, T., Saito, K., Suzuki, K., Hashimoto, S., Ohashi, K. Excess maternal fructose consumption impairs hippocampal function in offspring via epigenetic modification of BDNF promoter.

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