title: Increased truncated TrkB receptor expression and decreased BDNF/TrkB signaling in the frontal cortex of reeler mouse model of schizophrenia.
abstract: Heterozygous reeler mouse has been used as an animal model for schizophrenia based on several neuropathological and behavioral abnormalities homologous to schizophrenia. Since some of these abnormalities are primarily associated with altered BDNF signaling we investigated BDNF signaling in the frontal cortex of reeler mice in order to shed some light on the neuropathology and treatment of schizophrenia. BDNF, TrkB receptor isoforms (full-length and truncated), reelin, GAD67, GAD65, p75NTR, and NRH-2 levels were measured in the frontal cortex samples from reeler (B6C3Fe a/a-Reln rl/+) and wild-type (WT) mice. BDNF protein levels were significantly higher in reeler compared to WT. The protein levels of full-length TrkB were not altered in reeler mice, but both mRNA and protein levels of truncated TrkB were significantly higher. Protein analysis showed that TrkB activity, as indicated by the levels of tyrosine-phosphorylated TrkB, was lower in reeler mice. We did not find any significant change in the levels of p75NTR and NRH-2, regulatory proteins of TrkB signaling, in the reeler mice. Furthermore, we found significant reduction in reelin and GAD67 expressions, but not GAD65 expression in reeler compared to WT mice. In summary, molecular processes associated with defective BDNF signaling in reeler mice provide new therapeutic targets for neuroprotective pharmacotherapy for schizophrenia.
authors.affiliation: Department of Psychiatry and Health Behavior, Medical College of Georgia and Medical Research Service, Veterans Affairs Medical Center, Augusta, GA 30907, USA. apillai@mail.mcg.edu
authors.forename: Anilkumar
authors.initials: A
authors.lastname: Pillai
authors.forename: Sahebarao P
authors.initials: SP
authors.lastname: Mahadik
mesh_terms: D000818:Animals; D015153:Blotting, Western; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D015816:Cell Adhesion Molecules, Neuronal / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D004195:Disease Models, Animal; D016326:Extracellular Matrix Proteins / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D005625:Frontal Lobe / Q000737:chemistry / Q000378:metabolism* / Q000503:physiopathology; D015870:Gene Expression; D005968:Glutamate Decarboxylase / Q000235:genetics* / Q000378:metabolism; D006579:Heterozygote; D006801:Humans; D007118:Immunoassay; D047908:Intracellular Signaling Peptides and Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008818:Mice, Neurologic Mutants; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D009474:Neurons / Q000378:metabolism / Q000502:physiology; D017397:Prefrontal Cortex / Q000378:metabolism / Q000503:physiopathology; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D020813:Receptor, trkB / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D018079:Receptors, GABA / Q000235:genetics / Q000502:physiology; D000091042:Reelin Protein; D012559:Schizophrenia / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D012697:Serine Endopeptidases / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics* / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000032:analysis / Q000235:genetics*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D018079:Receptors, GABA; D000091042:Reelin Protein; D005680:gamma-Aminobutyric Acid; D020813:Receptor, trkB; C000717127:RELN protein, human; C000717128:Reln protein, mouse; D012697:Serine Endopeptidases; D005968:Glutamate Decarboxylase