Mapping of hippocampal gene clusters regulated by the amygdala to nonlinkage sites for schizophrenia

[SCHIZOBANK - The Hungarian national schizophrenia biobank and its role in schizophrenia research and in personalized medicine]

Delineating the pathogenesis of multifactorial diseases is a major challenge of the postgenomial era. Genetic factors are known to play an important role in the pathogenesis of certain psychiatric disorders as well as in the development of adverse reactions to psychoactive drugs. Containing large numbers of samples and linking them clinical data, biobanks are gaining importance in the studies of chronic multifactorial diseases. Several biobanks are under establishment in Hungary. The first initiative to collect samples in neurological and psychiatric disorders was the NEPSYBANK coordinated by the Hungarian Society of Clinical Neurogenetics. The national biobank network is currently established by the NEKIFUT project of the National Office of Research and Technology. In this article we describe the structure, logistics and informatical background of the national schizophrenia biobank (SCHIZOBANK). The initiative of the SCHIZOBANK originates from a consortium in which academy and health industry partners are collecting biological materials and data in five major psychiatric center under the coordination of the Medical and Health Science Center of the University of Debrecen. We review other international schizophrenia biobanks as well. Major strength of the SCHIZOBANK is the collection of very detailed phenotypic data and of RNA and plasma both in psychotic and non-psychotic state of the patient which permits longitudinal follow-up and the study of both static and dynamically changing transcriptomic, proteomic and metabolomic markers. The collection of the SCHIZOBANK is available not only to consortial partners but to other national and international research groups as well.

Regulation of the GABA cell phenotype in hippocampus of schizophrenics and bipolars

GABAergic dysfunction is present in the hippocampus in schizophrenia (SZ) and bipolar disorder (BD). The trisynaptic pathway was "deconstructed" into various layers of sectors CA3/2 and CA1 and gene expression profiling performed. Network association analysis was used to uncover genes that may be related to regulation of glutamate decarboxylase 67 (GAD(67)), a marker for this system that has been found by many studies to show decreased expression in SZs and BDs. The most striking change was a down-regulation of GAD(67) in the stratum oriens (SO) of CA2/3 in both groups; CA1 only showed changes in the SO of schizophrenics. The network generated for GAD(67) contained 25 genes involved in the regulation of kainate receptors, TGF-beta and Wnt signaling, as well as transcription factors involved in cell growth and differentiation. In SZs, IL-1beta, (GRIK2/3), TGF-beta2, TGF-betaR1, histone deacetylase 1 (HDAC1), death associated protein (DAXX), and cyclin D2 (CCND2) were all significantly up-regulated, whereas in BDs, PAX5, Runx2, LEF1, TLE1, and CCND2 were significantly down-regulated. In the SO of CA1 of BDs, where GAD67 showed no expression change, TGF-beta and Wnt signaling genes were all up-regulated, but other transcription factors showed no change in expression. In other layers/sectors, BDs showed no expression changes in these GAD(67) network genes. Overall, these results are consistent with the hypothesis that decreased expression of GAD(67) may be associated with an epigenetic mechanism in SZ. In BD, however, a suppression of transcription factors involved in cell differentiation may contribute to GABA dysfunction.