Reduced GSK-3beta MRNA Levels in Postmortem Dorsolateral Prefrontal Cortex of Schizophrenic Patients

Glycogen Synthase Kinase (GSK)-3 is a ubiquitous serine/threonine protein kinase highly abundant in brain which plays a key role in neural development and neuron survival. We have previously reported that GSK-3beta protein levels and GSK-3 activity are reduced by over 40% in postmortem prefrontal cortex of schizophrenic patients compared to patients with bipolar illness, unipolar depression and to normal controls, and Emamian et al. have recently presented convergent evidence for impaired AKT1-GSK-3beta signaling in schizophrenia. Using specimens of dorsolateral prefrontal cortex tissue obtained from The Stanley Medical Research Institute's Brain Collection, from the same subjects used previously, we now show that GSK-3beta, but not GSK-3alpha, mRNA levels are 36% lower in the patients with schizophrenia compared to all other comparison groups. The present study lends further support to the finding of low GSK-3beta levels in schizophrenia and extends this observation by suggesting that the decrease in GSK-3beta may be due to reduced protein synthesis possibly due to altered transcriptional drive of the GSK-3beta gene.