title: Generation and behavioral characterization of beta-catenin forebrain-specific conditional knock-out mice.
abstract: The canonical Wnt pathway and beta-catenin have been implicated in the pathophysiology of mood disorders. We generated forebrain-specific CRE-mediated conditional beta-catenin knock-out mice to begin exploring the behavioral implications of decreased Wnt pathway signaling in the central nervous system. In situ hybridization revealed a progressive knock-out of beta-catenin that began between 2 and 4 weeks of age, and by 12 weeks resulted in considerably decreased beta-catenin expression in regions of the forebrain, including the frontal cortex, hippocampus, and striatum. A significant decrease in protein levels of beta-catenin in these brain regions was observed by Western blot. Behavioral characterization of these mice in several tests (including the forced swim test, tail suspension test (TST), learned helplessness, response and sensitization to stimulants, and light/dark box among other tests) revealed relatively circumscribed alterations. In the TST, knock-out mice spent significantly less time struggling (a depression-like phenotype). However, knock-out mice did not differ from their wild-type littermates in the other behavioral tests of mood-related or anxiety-related behaviors. These results suggest that a 60-70% beta-catenin reduction in circumscribed brain regions is only capable of inducing subtle behavioral changes. Alternatively, regulating beta-catenin may modulate drug effects rather than being a model of mood disorder pathophysiology per se.
authors.affiliation: Laboratory of Molecular Pathophysiology and Experimental Therapeutics, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA. tgould@psych.umaryland.edu
authors.forename: Todd D
authors.initials: TD
authors.lastname: Gould
authors.forename: Kelley C
authors.initials: KC
authors.lastname: O'Donnell
authors.forename: Alyssa M
authors.initials: AM
authors.lastname: Picchini
authors.forename: Eliot R
authors.initials: ER
authors.lastname: Dow
authors.forename: Guang
authors.initials: G
authors.lastname: Chen
authors.forename: Husseini K
authors.initials: HK
authors.lastname: Manji
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001007:Anxiety / Q000235:genetics / Q000378:metabolism*; D001522:Behavior, Animal / Q000502:physiology*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000235:genetics; D004195:Disease Models, Animal; D005625:Frontal Lobe / Q000378:metabolism; D005818:Genetic Engineering / Q000379:methods; D006624:Hippocampus / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D019964:Mood Disorders / Q000235:genetics / Q000378:metabolism*; D017072:Neostriatum / Q000378:metabolism; D011401:Promoter Regions, Genetic; D016548:Prosencephalon / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D018709:Statistics, Nonparametric; D051153:Wnt Proteins / Q000378:metabolism*; D051176:beta Catenin / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D051153:Wnt Proteins; D051176:beta Catenin; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2