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Hollins S.L.,University of Newcastle | Hollins S.L.,Schizophrenia Research Institute | Hollins S.L.,Hunter Medical Research Institute | Zavitsanou K.,University of New South Wales | And 6 more authors.
Translational Psychiatry | Year: 2014

A significant feature of the cortical neuropathology of schizophrenia is a disturbance in the biogenesis of short non-coding microRNA (miRNA) that regulate translation and stability of mRNA. While the biological origin of this phenomenon has not been defined, it is plausible that it relates to major environmental risk factors associated with the disorder such as exposure to maternal immune activation (MIA) and adolescent cannabis use. To explore this hypothesis, we administered the viral mimic poly I:C to pregnant rats and further exposed some of their maturing offsprings to daily injections of the synthetic cannabinoid HU210 for 14 days starting on postnatal day 35. Whole-genome miRNA expression analysis was then performed on the left and right hemispheres of the entorhinal cortex (EC), a region strongly associated with schizophrenia. Animals exposed to either treatment alone or in combination exhibited significant differences in the expression of miRNA in the left hemisphere, whereas the right hemisphere was less responsive. Hemisphere-associated differences in miRNA expression were greatest in the combined treatment and highly over-represented in a single imprinted locus on chromosome 6q32. This observation was significant as the syntenic 14q32 locus in humans encodes a large proportion of miRNAs differentially expressed in peripheral blood lymphocytes from patients with schizophrenia, suggesting that interaction of early and late environmental insults may affect miRNA expression, in a manner that is relevant to schizophrenia. © 2014 Macmillan Publishers Limited. Source

Fillman S.G.,Schizophrenia Research Institute | Fillman S.G.,Schizophrenia Research Laboratory | Fillman S.G.,University of New South Wales | Cloonan N.,University of Queensland | And 11 more authors.
Molecular Psychiatry | Year: 2013

Upregulation of the immune response may be involved in the pathogenesis of schizophrenia with changes occurring in both peripheral blood and brain tissue. To date, microarray technology has provided a limited view of specific inflammatory transcripts in brain perhaps due to sensitivity issues. Here we used SOLiD Next Generation Sequencing to quantify neuroimmune mRNA expression levels in the dorsolateral prefrontal cortex of 20 individuals with schizophrenia and their matched controls. We detected 798 differentially regulated transcripts present in people with schizophrenia compared with controls. Ingenuity pathway analysis identified the inflammatory response as a key change. Using quantitative real-time PCR we confirmed the changes in candidate cytokines and immune modulators, including interleukin (IL)-6, IL-8, IL-1β and SERPINA3. The density of major histocompatibility complex-II-positive cells morphologically resembling microglia was significantly increased in schizophrenia and correlated with IL-1β expression. A group of individuals, most of whom had schizophrenia, were found to have increased inflammatory mRNA expression. In summary, we have demonstrated changes in an inflammatory response pathway that are present in ∼40% of people diagnosed with schizophrenia. This suggests that therapies aimed at immune system attenuation in schizophrenia may be of direct benefit in the brain. © 2013 Macmillan Publishers Limited. Source

Lambe E.K.,University of Toronto | Fillman S.G.,Schizophrenia Research Institute | Fillman S.G.,Schizophrenia Research Laboratory | Fillman S.G.,University of New South Wales | And 4 more authors.
PLoS ONE | Year: 2011

Serotonin and its receptors (HTRs) play critical roles in brain development and in the regulation of cognition, mood, and anxiety. HTRs are highly expressed in human prefrontal cortex and exert control over prefrontal excitability. The serotonin system is a key treatment target for several psychiatric disorders; however, the effectiveness of these drugs varies according to age. Despite strong evidence for developmental changes in prefrontal Htrs of rodents, the developmental regulation of HTR expression in human prefrontal cortex has not been examined. Using postmortem human prefrontal brain tissue from across postnatal life, we investigated the expression of key serotonin receptors with distinct inhibitory (HTR1A, HTR5A) and excitatory (HTR2A, HTR2C, HTR4, HTR6) effects on cortical neurons, including two receptors which appear to be expressed to a greater degree in inhibitory interneurons of cerebral cortex (HTR2C, HTR6). We found distinct developmental patterns of expression for each of these six HTRs, with profound changes in expression occurring early in postnatal development and also into adulthood. However, a collective look at these HTRs in terms of their likely neurophysiological effects and major cellular localization leads to a model that suggests developmental changes in expression of these individual HTRs may not perturb an overall balance between inhibitory and excitatory effects. Examining and understanding the healthy balance is critical to appreciate how abnormal expression of an individual HTR may create a window of vulnerability for the emergence of psychiatric illness. © 2011 Lambe et al. Source

Oh D.H.,Hanyang University | Oh D.,CHA Medical University | Son H.,Hanyang University | Webster M.J.,Stanley Medical Research Institute | And 2 more authors.
Journal of Neural Transmission | Year: 2014

Previous human postmortem studies have shown that expression of glutamate transporters (SLC1A2 and SLC1A3) and gamma-aminobutyric acid-synthesizing enzyme [glutamic acid decarboxylase 1 (GAD1)] are reduced in the dorsolateral prefrontal cortex (dlPFC) in subjects with major depressive disorder (MDD). However, no studies have explored the association between these two molecules and its related biological processes in MDD because of limited postmortem sample availability. Data sharing using the Stanley neuropathology consortium integrative database (SNCID), a web-based tool that integrates datasets from the same postmortem brain samples, allowed us to reanalyze existing postmortem data efficiently. We found two datasets where the mRNA levels of GAD1 and SLC1A2 in subregions of the dlPFC were significantly and marginally lower in subjects with MDD (n = 15) than in controls (n = 15) (p = 0.045 and 0.057, respectively). In addition, there was a positive correlation between these two molecules (n = 30, p < 0.05). Spearman's rank correlation analysis using all available datasets revealed that the expression levels of both GAD1 and SLC1A2 mRNAs were commonly correlated with the expression levels of several neuropathological markers in the dlPFC in all of the SNCID subjects (n = 60, p < 0.001). Most of these markers are known to be involved in the RAF/MEK/ERK signal transduction pathway. This exploratory study provides an initial step for future studies to investigate an association between the reductions in SLC1A2 and GAD1 mRNA expression and their relation to the attenuation of the RAF/MEK/ERK signaling pathway in the dlPFC in MDD. The integration of the existing archival data may shed light on one important aspect of the pathophysiology of MDD. © 2014 Springer-Verlag. Source

Wong J.,Schizophrenia Research Institute | Wong J.,Schizophrenia Research Laboratory | Wong J.,University of New South Wales | Woon H.G.,Schizophrenia Research Institute | And 4 more authors.
Molecular and Cellular Neuroscience | Year: 2011

In this study, we determined if estrogen receptor alpha (ERα) can interact with the full length tropomyosin receptor kinase B (TrkB-TK+), both of which are implicated in schizophrenia pathogenesis. Using neuronal (SHSY5Y) and non-neuronal (CHOK1) cell-lines, we showed that TrkB-TK+ can increase transcription at estrogen response elements (EREs) with and without exogenous estrogen treatment. In the presence of estrogen, TrkB-TK+ further potentiated the effect of estrogen stimulation on ERα-mediated transcription. This synergistic effect of TrkB-TK+ on ERα-mediated transcription was not due to direct effects of TrkB-TK+ in the nucleus, but occurred through cytoplasmic signaling of TrkB-TK+ via the MAPK/ERK pathway to phosphorylate ERα, leading to an induction in ERα-mediated transcription. When we examined the PI3K/AKT pathway, we found that PI3K/AKT activity constitutively inhibited baseline transcription at EREs. Furthermore, we showed that signaling via PI3K/AKT inhibited TrkB-TK+-dependent transcriptional potentiation at EREs. Our findings suggest that TrkB-TK+-linked second messenger signaling pathways can reciprocally regulate ERα-mediated transcription at EREs. Considering that both ERα and TrkB-TK+ expression are reduced in schizophrenia, our findings suggest that dysfunction in TrkB-TK+ signaling may occur upstream of, or in conjunction with a dysfunction in ERα, and that transcriptional regulation by ERα may be decreased by reductions in TrkB-TK+. © 2010. Source

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