Increased expression of Wnt-1 in schizophrenic brains

The regulated expression of Wnt-1, one member of the wingless/Wnt pathway, in the brain is critical for many neurodevelopmental processes. Recently, i t has been reported that the wingless/Wnt pathway participates in a complex behavioral phenomenon and suggested that this pathway's molecules are cand idate genes for neuropsychiatric disorders. Thus, we investigated the expre ssion of Wnt-1 in the hippocampal region, which is believed to be closely i nvolved in the pathophysiology of schizophrenia, of postmortem brains from 10 schizophrenic and 10 control individuals. Immunohistochemical analysis w ith polyclonal antibodies recognizing Wnt-1 revealed immunoreactivity prima rily in the pyramidal cell layer, particularly in CA3 and CA4 regions. We o bserved a significant elevation in the number of Wnt-1-immunoreactive neuro ns in the great majority of schizophrenic brains relative to that in contro ls. The expression of Wnt-1 may be related to cell adhesion, synaptic rearr angement, and plasticity. Therefore, the increase in Wnt-1 immunoreactivity in schizophrenic hippocampi suggests an altered plasticity of this structu re in a large proportion of schizophrenic brains. These findings suggest an abnormality of the wingless/Wnt pathway present in the schizophrenic brain and may support the 'neurodevelopmental hypothesis' of schizophrenia. (C) 1999 Elsevier Science B.V. All rights reserved.