title: Insulin-Like Growth Factor Binding Protein-3 Deficiency Leads to Behavior Impairment with Monoaminergic and Synaptic Dysfunction.
abstract: Insulin-like growth factor binding protein (IGFBP)-3 regulates IGF bioactivity, induces apoptosis, and inhibits cell growth independent of IGFs, but the functional role of IGFBP3 in the brain is not clear. In the present study, we revealed the effect of IGFBP3 on the brain by characterizing the phenotype of Igfbp3-null mice. Compared with wild-type mice, Igfbp3-null mice had significantly decreased IGF-1 content in the brain but no change in weights of brain and body. In Igfbp3-null mice, the number of dendritic spines was significantly reduced, and the dendritic diameter was thickening. In addition, in Igfbp3-null mice, a decrease in phosphorylated Akt and ERK1/2 significantly reduced PSD-95 expression, and GAD65/67 expression was significantly decreased. These results indicate that IGFBP3 deficiency impairs neuronal structure and signaling. In behavioral studies, Igfbp3-null mice were hyperactive, and a Y-maze alternation test revealed impaired spatial working memory but no anxiety-like behavior. Monoaminergic analysis using high-performance liquid chromatography indicated that Igfbp3-null mice had lower levels of dopamine and serotonin compared with wild-type mice, suggesting an abnormal monoaminergic neurotransmission. In conclusion, our studies found that the deletion of IGFBP3 results in behavioral impairments that are associated with abnormal synaptic function and monoaminergic neurotransmission, which helps to characterize the critical role of IGFBP3 in the brain.
authors.affiliation: Department of Mental Retardation and Birth Defect Research, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Dai
authors.affiliation: Department of Mental Retardation and Birth Defect Research, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
authors.forename: Yu-Ichi
authors.initials: YI
authors.lastname: Goto
authors.affiliation: Department of Mental Retardation and Birth Defect Research, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan. Electronic address: itoh@ncnp.go.jp.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Itoh
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism* / Q000473:pathology*; D002851:Chromatography, High Pressure Liquid; D004195:Disease Models, Animal; D007150:Immunohistochemistry; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000172:deficiency*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009474:Neurons / Q000473:pathology; D009435:Synaptic Transmission / Q000502:physiology*
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3