Gene expression in superior temporal cortex of schizophrenia patients

We investigated gene expression pattern obtained from microarray data of 10 schizophrenia patients and 10 control subjects. Brain tissue samples were obtained postmortem; thus, the different ages of the patients at death also allowed a study of the dynamic behavior of the expression patterns over a time frame of many years. We used statistical tests and dimensionality reduction methods to characterize the subset of genes differentially expressed in the two groups. A set of 10 genes were significantly downregulated, and a larger set of 40 genes were upregulated in the schizophrenia patients. Interestingly, the set of upregulated genes includes a large number of genes associated with gene transcription (zinc finger proteins and histone methylation) and apoptosis. We furthermore identified genes with a significant trend correlating with age in the control (MLL3) or the schizophrenia group (SOX5, CTRL). Assessments of correlations of other genes with the disorder (RRM1) or with the duration of medication could not be resolved, because all patients were medicated. This hypothesis-free approach uncovered a series of genes differentially expressed in schizophrenia that belong to a number of distinct cell functions, such as apoptosis, transcriptional regulation, cell motility, energy metabolism and hypoxia.

DnaJB6 is present in the core of Lewy bodies and is highly up-regulated in parkinsonian astrocytes

DnaJ/Hsp40 chaperones determine the activity of Hsp70s by stabilizing their interaction with substrate proteins. We have predicted, based on the in silico analysis of a brain-derived whole-genome transcriptome data set, an increased expression of DnaJ/Hsp40 homologue, subfamily B, member 6 (DnaJB6) in Parkinson's disease (PD; Moran et al. [2006] Neurogenetics 7:1-11). We now show that DnaJB6 is a novel component of Lewy bodies (LBs) in both PD substantia nigra and PD cortex and that it is strongly up-regulated in parkinsonian astrocytes. The presence of DnaJB6 in the center of LBs suggests an early and direct involvement of this chaperone in the neuronal disease process associated with PD. The strong concomitant expression of DnaJB6 in astrocytes emphasizes the involvement of glial cells in PD and could indicate a route for therapeutic intervention. Extracellular alpha-synuclein originating from intravesicular alpha-synuclein is prone to aggregation and the potential source of extracellular aggregates (Lee [2008] J. Mol. Neurosci. 34:17-22). The observed strong expression of DnaJB6 by astrocytes could reflect a protective reaction, so reducing the neuronal release of toxic alpha-synuclein and supporting the astrocyte response in PD might limit the progression of the disease process.