Characteristics of vasculogenic mimicry and tumour to endothelial transdifferentiation in human glioblastoma: a systematic review.

BACKGROUND: Glioblastoma, the most common primary malignant brain tumour in adults, is a highly vascular tumour characterised by abnormal angiogenesis. Additional mechanisms of tumour vascularisation have also been reported in glioblastoma, including the formation of tumour cell-derived vessels by vasculogenic mimicry (VM) or the transdifferentiation of tumour cells to endothelial cells. VM and endothelial transdifferentiation have frequently been reported as distinct processes, however, the use of both terms to describe a single process of vascularisation also occurs. Some overlapping characteristics have also been reported when identifying each process. We therefore aimed to determine the markers consistently attributed to VM and endothelial transdifferentiation in the glioblastoma literature. METHODS: Ovid MEDLINE and Ovid Embase were searched for studies published between January 1999 and July 2021 that assessed VM or tumour to endothelial transdifferentiation in human glioblastoma. The online systematic review tool Covidence was used for screening and data extraction. Extracted data included type of tumour-derived vasculature reported, methods and techniques used, and markers investigated. Studies were grouped based on type of vasculature reported for further assessment. RESULTS: One hundred and thirteen of the 419 unique records identified were included for analysis. VM was reported in 64/113 studies, while tumour to endothelial transdifferentiation was reported in 16/113 studies. The remaining studies used both terms to describe a single process, did not define the process that occurred, or concluded that neither VM nor endothelial transdifferentiation occurred. Absence of CD34 and/or CD31 in vascular structures was the most common indicator of VM, while expression of CD34 and/or CD31, in addition to various other endothelial, stem cell or tumour cell markers, indicated tumour to endothelial transdifferentiation. CONCLUSION: Cells derived from tumour to endothelial transdifferentiation express typical endothelial markers including CD34 and CD31, while tumour cells contributing to VM lack CD34 and CD31 expression. Additional tumour markers are required to identify transdifferentiation in glioblastoma tissue, and this process requires further characterisation.

Comparison between [68Ga]Ga-PSMA-617 and [18F]FET PET as Imaging Biomarkers in Adult Recurrent Glioblastoma.

The aim of this prospective clinical study was to evaluate the potential of the prostate specific membrane antigen (PSMA) targeting ligand, [68Ga]-PSMA-Glu-NH-CO-NH-Lys-2-naphthyl-L-Ala-cyclohexane-DOTA ([68Ga]Ga-PSMA-617) as a positron emission tomography (PET) imaging biomarker in recurrent glioblastoma patients. Patients underwent [68Ga]Ga-PSMA-617 and O-(2-[18F]-fluoroethyl)-L-tyrosine ([18F]FET) PET scans on two separate days. [68Ga]Ga-PSMA-617 tumour selectivity was assessed by comparing tumour volume delineation and by assessing the intra-patient correlation between tumour uptake on [68Ga]Ga-PSMA-617 and [18F]FET PET images. [68Ga]Ga-PSMA-617 tumour specificity was evaluated by comparing its tumour-to-brain ratio (TBR) with [18F]FET TBR and its tumour volume with the magnetic resonance imaging (MRI) contrast-enhancing (CE) tumour volume. Ten patients were recruited in this study. [68Ga]Ga-PSMA-617-avid tumour volume was larger than the [18F]FET tumour volume (p = 0.063). There was a positive intra-patient correlation (median Pearson r = 0.51; p < 0.0001) between [68Ga]Ga-PSMA-617 and [18F]FET in the tumour volume. [68Ga]Ga-PSMA-617 had significantly higher TBR (p = 0.002) than [18F]FET. The [68Ga]Ga-PSMA-617-avid tumour volume was larger than the CE tumour volume (p = 0.0039). Overall, accumulation of [68Ga]-Ga-PSMA-617 beyond [18F]FET-avid tumour regions suggests the presence of neoangiogenesis in tumour regions that are not overly metabolically active yet. Higher tumour specificity suggests that [68Ga]-Ga-PSMA-617 could be a better imaging biomarker for recurrent tumour delineation and secondary treatment planning than [18F]FET and CE MRI.

Wnt receptor gene FZD1 was associated with schizophrenia in genome-wide SNP analysis of the Australian Schizophrenia Research Bank cohort.

OBJECTIVES: Large-scale genetic analysis of common variation in schizophrenia has been a powerful approach to understanding this complex but highly heritable psychotic disorder. To further investigate loci, genes and pathways associated more specifically in the well-characterized Australian Schizophrenia Research Bank cohort, we applied genome-wide single-nucleotide polymorphism analysis in these three annotation categories. METHODS: We performed a case-control genome-wide association study in 429 schizophrenia samples and 255 controls. Post-genome-wide association study analyses were then integrated with genomic annotations to explore the enrichment of variation at the gene and pathway level. We also examine candidate single-nucleotide polymorphisms with potential function within expression quantitative trait loci and investigate overall enrichment of variation within tissue-specific functional regulatory domains of the genome. RESULTS: The strongest finding (p = 2.01 × 10-6, odds ratio = 1.82, 95% confidence interval = [1.42, 2.33]) in genome-wide association study was with rs10252923 at 7q21.13, downstream of FZD1 (frizzled class receptor 1). While this did not stand alone after correction, the involvement of FZD1 was supported by gene-based analysis, which exceeded the threshold for genome-wide significance (p = 2.78 × 10-6). CONCLUSION: The identification of FZD1, as an independent association signal at the gene level, supports the hypothesis that the Wnt signalling pathway is altered in the pathogenesis of schizophrenia and may be an important target for therapeutic development.

Altered neural signaling and immune pathways in peripheral blood mononuclear cells of schizophrenia patients with cognitive impairment: A transcriptome analysis.

Cognitive deficits are a core feature of schizophrenia and contribute significantly to functional disability. We investigated the molecular pathways associated with schizophrenia (SZ; n=47) cases representing both 'cognitive deficit' (CD; n=22) and 'cognitively spared' (CS; n=25) subtypes of schizophrenia (based on latent class analysis of 9 cognitive performance indicators), compared with 49 healthy controls displaying 'normal' cognition. This was accomplished using gene-set analysis of transcriptome data derived from peripheral blood mononuclear cells (PBMCs). We detected 27 significantly altered pathways (19 pathways up-regulated and 8 down-regulated) in the combined SZ group and a further 6 pathways up-regulated in the CS group and 5 altered pathways (4 down-regulated and 1 up-regulated) in the CD group. The transcriptome profiling in SZ and cognitive subtypes were characterized by the up-regulated pathways involved in immune dysfunction (e.g., antigen presentation in SZ), energy metabolism (e.g., oxidative phosphorylation), and down-regulation of the pathways involved in neuronal signaling (e.g., WNT in SZ/CD and ERBB in SZ). When we looked for pathways that differentiated the two cognitive subtypes we found that the WNT signaling was significantly down-regulated (FDR<0.05) in the CD group in accordance with the combined SZ cohort, whereas it was unaffected in the CS group. This suggested suppression of WNT signaling was a defining feature of cognitive decline in schizophrenia. The WNT pathway plays a role in both the development/function of the central nervous system and peripheral tissues, therefore its alteration in PBMCs may be indicative of an important genomic axis relevant to cognition in the neuropathology of schizophrenia.

Antipsychotic drug-associated gene-miRNA interaction in T-lymphocytes.

Antipsychotic drugs (APDs) can have a profound effect on the human body that extends well beyond our understanding of their neuropsychopharmacology. Some of these effects manifest themselves in peripheral blood lymphocytes, and in some cases, particularly in clozapine treatment, result in serious complications. To better understand the molecular biology of APD action in lymphocytes, we investigated the influence of chlorpromazine, haloperidol and clozapine in vitro, by microarray-based gene and microRNA (miRNA) expression analysis. JM-Jurkat T-lymphocytes were cultured in the presence of the APDs or vehicle alone over 2 wk to model the early effects of APDs on expression. Interestingly both haloperidol and clozapine appear to regulate the expression of a large number of genes. Functional analysis of APD-associated differential expression revealed changes in genes related to oxidative stress, metabolic disease and surprisingly also implicated pathways and biological processes associated with neurological disease consistent with current understanding of the activity of APDs. We also identified miRNA-mRNA interaction associated with metabolic pathways and cell death/survival, all which could have relevance to known side effects of APDs. These results indicate that APDs have a significant effect on expression in peripheral tissue that relate to both known mechanisms as well as poorly characterized side effects.

Upregulation of the Renin-Angiotensin System Is Associated with Patient Survival and the Tumour Microenvironment in Glioblastoma.

Glioblastoma is a highly aggressive disease with poor survival outcomes. An emerging body of literature links the role of the renin-angiotensin system (RAS), well-known for its function in the cardiovascular system, to the progression of cancers. We studied the expression of RAS-related genes (ATP6AP2, AGTR1, AGTR2, ACE, AGT, and REN) in The Cancer Genome Atlas (TCGA) glioblastoma cohort, their relationship to patient survival, and association with tumour microenvironment pathways. The expression of RAS genes was then examined in 12 patient-derived glioblastoma cell lines treated with chemoradiation. In cases of glioblastoma within the TCGA, ATP6AP2, AGTR1, ACE, and AGT had consistent expressions across samples, while AGTR2 and REN were lowly expressed. High expression of AGTR1 was independently associated with lower progression-free survival (PFS) (p = 0.01) and had a non-significant trend for overall survival (OS) after multivariate analysis (p = 0.095). The combined expression of RAS receptors (ATP6AP2, AGTR1, and AGTR2) was positively associated with gene pathways involved in hypoxia, microvasculature, stem cell plasticity, and the molecular characterisation of glioblastoma subtypes. In patient-derived glioblastoma cell lines, ATP6AP2 and AGTR1 were upregulated after chemoradiotherapy and correlated with an increase in HIF1A expression. This data suggests the RAS is correlated with changes in the tumour microenvironment and associated with glioblastoma survival outcomes.

ATR inhibition using gartisertib enhances cell death and synergises with temozolomide and radiation in patient-derived glioblastoma cell lines.

Glioblastoma cells can restrict the DNA-damaging effects of temozolomide (TMZ) and radiation therapy (RT) using the DNA damage response (DDR) mechanism which activates cell cycle arrest and DNA repair pathways. Ataxia-telangiectasia and Rad3-Related protein (ATR) plays a pivotal role in the recognition of DNA damage induced by chemotherapy and radiation causing downstream DDR activation. Here, we investigated the activity of gartisertib, a potent ATR inhibitor, alone and in combination with TMZ and/or RT in 12 patient-derived glioblastoma cell lines. We showed that gartisertib alone potently reduced the cell viability of glioblastoma cell lines, where sensitivity was associated with the frequency of DDR mutations and higher expression of the G2 cell cycle pathway. ATR inhibition significantly enhanced cell death in combination with TMZ and RT and was shown to have higher synergy than TMZ+RT treatment. MGMT promoter unmethylated and TMZ+RT resistant glioblastoma cells were also more sensitive to gartisertib. Analysis of gene expression from gartisertib treated glioblastoma cells identified the upregulation of innate immune-related pathways. Overall, this study identifies ATR inhibition as a strategy to enhance the DNA-damaging ability of glioblastoma standard treatment, while providing preliminary evidence that ATR inhibition induces an innate immune gene signature that warrants further investigation.

Gene expression profiling in treatment-naive schizophrenia patients identifies abnormalities in biological pathways involving AKT1 that are corrected by antipsychotic medication.

Distinct gene expression profiles can be detected in peripheral blood mononuclear cells (PBMCs) in patients with schizophrenia; however, little is known about the effects of antipsychotic medication. This study compared gene expression profiles in PMBCs from treatment-naive patients with schizophrenia before and after antipsychotic drug treatment. PBMCs were obtained from 10 treatment-naive schizophrenia patients before and 6 wk after initiating antipsychotic drug treatment and compared to PMBCs collected from 11 healthy community volunteers. Genome-wide expression profiling was conducted using Illumina HumanHT-12 expression bead arrays and analysed using significance analysis of microarrays. This analysis identified 624 genes with altered expression (208 up-regulated, 416 down-regulated) prior to antipsychotic treatment (p < 0.05) including schizophrenia-associated genes AKT1, DISC1 and DGCR6. After 6-8 wk treatment of patients with risperidone or risperidone in combination with haloperidol, only 106 genes were altered, suggesting that the treatment corrected the expression of a large proportion of genes back to control levels. However, 67 genes continued to show the same directional change in expression after treatment. Ingenuity® pathway analysis and gene set enrichment analysis implicated dysregulation of biological functions and pathways related to inflammation and immunity in patients with schizophrenia. A number of the top canonical pathways dysregulated in treatment-naive patients signal through AKT1 that was up-regulated. After treatment, AKT1 returned to control levels and less dysregulation of these canonical pathways was observed. This study supports immune dysfunction and pathways involving AKT1 in the aetiopathophysiology of schizophrenia and their response to antipsychotic medication.

Design and interpretation of microRNA-reporter gene activity.

MicroRNAs (miRNAs) are small noncoding RNA molecules that act as sequence specificity guides to direct post-transcriptional gene silencing. In doing so, miRNAs regulate many critical developmental processes, including cellular proliferation, differentiation, migration, and apoptosis, as well as more specialized biological functions such as dendritic spine development and synaptogenesis. Interactions between miRNAs and their miRNA recognition elements occur via partial complementarity, rendering tremendous redundancy in targeting such that miRNAs are predicted to regulate 60% of the genome, with each miRNA estimated to regulate more than 200 genes. Because these predictions are prone to false positives and false negatives, there is an ever present need to provide material support to these assertions to firmly establish the biological function of specific miRNAs in both normal and pathophysiological contexts. Using schizophrenia-associated miR-181b as an example, we present detailed guidelines and novel insights for the rapid establishment of a streamlined miRNA-reporter gene assay and explore various design concepts for miRNA-reporter gene applications, including bidirectional miRNA modulation. In exemplifying this approach, we report seven novel miR-181b target sites for five schizophrenia candidate genes (DISC1, BDNF, ENKUR, GRIA1, and GRIK1) and dissect a number of vital concepts regarding future developments for miRNA-reporter gene assays and the interpretation of their results.

Vasculogenic Mimicry Occurs at Low Levels in Primary and Recurrent Glioblastoma.

Vasculogenic mimicry (VM), the ability of tumour cells to form functional microvasculature without an endothelial lining, may contribute to anti-angiogenic treatment resistance in glioblastoma. We aimed to assess the extent of VM formation in primary and recurrent glioblastomas and to determine whether VM vessels also express prostate-specific membrane antigen (PSMA), a pathological vessel marker. Formalin-fixed paraffin-embedded tissue from 35 matched pairs of primary and recurrent glioblastoma was immunohistochemically labelled for PSMA and CD34 and stained with periodic acid-Schiff (PAS). Vascular structures were categorised as endothelial vessels (CD34+/PAS+) or VM (CD34-/PAS+). Most blood vessels in both primary and recurrent tumours were endothelial vessels, and these significantly decreased in recurrent tumours (p < 0.001). PSMA was expressed by endothelial vessels, and its expression was also decreased in recurrent tumours (p = 0.027). VM was observed in 42.86% of primary tumours and 28.57% of recurrent tumours. VM accounted for only a small proportion of the tumour vasculature and VM density did not differ between primary and recurrent tumours (p = 0.266). The functional contribution of VM and its potential as a treatment target in glioblastoma require further investigation.

Alternative mRNA fates identified in microRNA-associated transcriptome analysis.

BACKGROUND: MicroRNA (miRNA) are small non-coding RNA molecules which function as nucleic acid-based specificity factors in the universal RNA binding complex known as the RNA induced silencing complex (RISC). In the canonical gene-silencing pathway, these activated RISC particles are associated with RNA decay and gene suppression, however, there is evidence to suggest that in some circumstances they may also stabilise their target RNA and even enhance translation. To further explore the role of miRNA in this context, we performed a genome-wide expression analysis to investigate the molecular consequences of bidirectional modulation of the disease-associated miRNAs miR-181b and miR-107 in multiple human cell lines. RESULTS: This data was subjected to pathways analysis and correlated against miRNA targets predicted through seed region homology. This revealed a large number of both conserved and non-conserved miRNA target genes, a selection of which were functionally validated through reporter gene assays. Contrary to expectation we also identified a significant proportion of predicted target genes with both conserved and non-conserved recognition elements that were positively correlated with the modulated miRNA. Finally, a large proportion of miR-181b associated genes devoid of the corresponding miRNA recognition element, were enriched with binding motifs for the E2F1 transcription factor, which is encoded by a miR-181b target gene. CONCLUSIONS: These findings suggest that miRNA regulate target genes directly through interactions with both conserved and non-conserved target recognition elements, and can lead to both a decrease and increase in transcript abundance. They also multiply their influence through interaction with transcription factor genes exemplified by the observed miR-181b/E2F1 relationship.

Finding the needle in the haystack: a review of microarray gene expression research into schizophrenia.

BACKGROUND: With an estimated 80% heritability, molecular genetic research into schizophrenia has remained inconclusive. Recent large-scale, genome-wide association studies only identified a small number of susceptibility genes with individually very small effect sizes. However, the variable expression of the phenotype is not well captured in diagnosis-based research as well as when assuming a 'heterogenic risk model' (as apposed to a monogenic or polygenic model). Hence, the expression of susceptibility genes in response to environmental factors in concert with other disease-promoting or protecting genes has increasingly attracted attention. METHOD: The current review summarises findings of microarray gene expression research with relevance to schizophrenia as they emerged over the past decade. RESULTS: Most findings from post mortem, peripheral tissues and animal models to date have linked altered gene expression in schizophrenia to presynaptic function, signalling, myelination, neural migration, cellular immune mechanisms, and response to oxidative stress consistent with multiple small effects of many individual genes. However, the majority of results are difficult to interpret due to small sample sizes (i.e. potential type-2 errors), confounding factors (i.e. medication effects) or lack of plausible neurobiological theory. CONCLUSION: Nevertheless, microarray gene expression research is likely to play an important role in the future when investigating gene/gene and gene/environment interactions by adopting a neurobiologically sound theoretical framework.

Transcriptomic Profiling of DNA Damage Response in Patient-Derived Glioblastoma Cells before and after Radiation and Temozolomide Treatment.

Glioblastoma is a highly aggressive, invasive and treatment-resistant tumour. The DNA damage response (DDR) provides tumour cells with enhanced ability to activate cell cycle arrest and repair treatment-induced DNA damage. We studied the expression of DDR, its relationship with standard treatment response and patient survival, and its activation after treatment. The transcriptomic profile of DDR pathways was characterised within a cohort of isocitrate dehydrogenase (IDH) wild-type glioblastoma from The Cancer Genome Atlas (TCGA) and 12 patient-derived glioblastoma cell lines. The relationship between DDR expression and patient survival and cell line response to temozolomide (TMZ) or radiation therapy (RT) was assessed. Finally, the expression of 84 DDR genes was examined in glioblastoma cells treated with TMZ and/or RT. Although distinct DDR cluster groups were apparent in the TCGA cohort and cell lines, no significant differences in OS and treatment response were observed. At the gene level, the high expression of ATP23, RAD51C and RPA3 independently associated with poor prognosis in glioblastoma patients. Finally, we observed a substantial upregulation of DDR genes after treatment with TMZ and/or RT, particularly in RT-treated glioblastoma cells, peaking within 24 h after treatment. Our results confirm the potential influence of DDR genes in patient outcome. The observation of DDR genes in response to TMZ and RT gives insight into the global response of DDR pathways after adjuvant treatment in glioblastoma, which may have utility in determining DDR targets for inhibition.

Sex-Dependent Shared and Nonshared Genetic Architecture Across Mood and Psychotic Disorders.

BACKGROUND: Sex differences in incidence and/or presentation of schizophrenia (SCZ), major depressive disorder (MDD), and bipolar disorder (BIP) are pervasive. Previous evidence for shared genetic risk and sex differences in brain abnormalities across disorders suggest possible shared sex-dependent genetic risk. METHODS: We conducted the largest to date genome-wide genotype-by-sex (G×S) interaction of risk for these disorders using 85,735 cases (33,403 SCZ, 19,924 BIP, and 32,408 MDD) and 109,946 controls from the PGC (Psychiatric Genomics Consortium) and iPSYCH. RESULTS: Across disorders, genome-wide significant single nucleotide polymorphism-by-sex interaction was detected for a locus encompassing NKAIN2 (rs117780815, p = 3.2 × 10-8), which interacts with sodium/potassium-transporting ATPase (adenosine triphosphatase) enzymes, implicating neuronal excitability. Three additional loci showed evidence (p < 1 × 10-6) for cross-disorder G×S interaction (rs7302529, p = 1.6 × 10-7; rs73033497, p = 8.8 × 10-7; rs7914279, p = 6.4 × 10-7), implicating various functions. Gene-based analyses identified G×S interaction across disorders (p = 8.97 × 10-7) with transcriptional inhibitor SLTM. Most significant in SCZ was a MOCOS gene locus (rs11665282, p = 1.5 × 10-7), implicating vascular endothelial cells. Secondary analysis of the PGC-SCZ dataset detected an interaction (rs13265509, p = 1.1 × 10-7) in a locus containing IDO2, a kynurenine pathway enzyme with immunoregulatory functions implicated in SCZ, BIP, and MDD. Pathway enrichment analysis detected significant G×S interaction of genes regulating vascular endothelial growth factor receptor signaling in MDD (false discovery rate-corrected p < .05). CONCLUSIONS: In the largest genome-wide G×S analysis of mood and psychotic disorders to date, there was substantial genetic overlap between the sexes. However, significant sex-dependent effects were enriched for genes related to neuronal development and immune and vascular functions across and within SCZ, BIP, and MDD at the variant, gene, and pathway levels.

DNA damage repair in glioblastoma: current perspectives on its role in tumour progression, treatment resistance and PIKKing potential therapeutic targets.

BACKGROUND: The aggressive, invasive and treatment resistant nature of glioblastoma makes it one of the most lethal cancers in humans. Total surgical resection is difficult, and a combination of radiation and chemotherapy is used to treat the remaining invasive cells beyond the tumour border by inducing DNA damage and activating cell death pathways in glioblastoma cells. Unfortunately, recurrence is common and a major hurdle in treatment, often met with a more aggressive and treatment resistant tumour. A mechanism of resistance is the response of DNA repair pathways upon treatment-induced DNA damage, which enact cell-cycle arrest and repair of DNA damage that would otherwise cause cell death in tumour cells. CONCLUSIONS: In this review, we discuss the significance of DNA repair mechanisms in tumour formation, aggression and treatment resistance. We identify an underlying trend in the literature, wherein alterations in DNA repair pathways facilitate glioma progression, while established high-grade gliomas benefit from constitutively active DNA repair pathways in the repair of treatment-induced DNA damage. We also consider the clinical feasibility of inhibiting DNA repair in glioblastoma and current strategies of using DNA repair inhibitors as agents in combination with chemotherapy, radiation or immunotherapy. Finally, the importance of blood-brain barrier penetrance when designing novel small-molecule inhibitors is discussed.

Low tumour-infiltrating lymphocyte density in primary and recurrent glioblastoma.

Immunotherapies targeting tumour-infiltrating lymphocytes (TILs) that express the immune checkpoint molecule programmed cell death-1 (PD-1) have shown promise in preclinical glioblastoma models but have had limited success in clinical trials. To assess when glioblastoma is most likely to benefit from immune checkpoint inhibitors we determined the density of TILs in primary and recurrent glioblastoma. Thirteen cases of matched primary and recurrent glioblastoma tissue were immunohistochemically labelled for CD3, CD8, CD4 and PD-1, and TIL density assessed. CD3+ TILs were observed in all cases, with the majority of both primary (69.2%) and recurrent (61.5%) tumours having low density of TILs present. CD8+ TILs were observed at higher densities than CD4+ TILs in both tumour groups. PD-1+ TILs were sparse and present in only 25% of primary and 50% of recurrent tumours. Quantitative analysis of TILs demonstrated significantly higher CD8+ TIL density at recurrence (p = 0.040). No difference was observed in CD3+ (p = 0.191), CD4+ (p = 0.607) and PD-1+ (p = 0.070) TIL density between primary and recurrent groups. This study shows that TILs are present at low densities in both primary and recurrent glioblastoma. Furthermore, PD-1+ TILs were frequently absent, which may provide evidence as to why anti-PD-1 immunotherapy trials have been largely unsuccessful in glioblastoma.

Dysregulation of miRNA 181b in the temporal cortex in schizophrenia.

Analysis of global microRNA (miRNA) expression in postmortem cortical grey matter from the superior temporal gyrus, revealed significant up-regulation of miR-181b expression in schizophrenia. This finding was supported by quantitative real-time RT-PCR analysis of miRNA expression in a cohort of 21 matched pairs of schizophrenia and non-psychiatric controls. The implications of this finding are substantial, as this miRNA is predicted to regulate many target genes with potential significance to the development of schizophrenia. They include the calcium sensor gene visinin-like 1 (VSNL1) and the ionotropic AMPA glutamate receptor subunit (GRIA2), which were found to be down-regulated in the same cortical tissue from the schizophrenia group. Both of these genes were also suppressed in miR-181b transfected cells and shown to contain functional miR-181b miRNA recognition elements by reporter gene assay. This study suggests altered miRNA levels could be a significant factor in the dysregulation of cortical gene expression in schizophrenia.

Different forms of glycine- and GABA(A)-receptor mediated inhibitory synaptic transmission in mouse superficial and deep dorsal horn neurons.

BACKGROUND: Neurons in superficial (SDH) and deep (DDH) laminae of the spinal cord dorsal horn receive sensory information from skin, muscle, joints and viscera. In both regions, glycine- (GlyR) and GABAA-receptors (GABAARs) contribute to fast synaptic inhibition. For rat, several types of GABAAR coexist in the two regions and each receptor type provides different contributions to inhibitory tone. Recent work in mouse has discovered an additional type of GlyR, (containing alpha 3 subunits) in the SDH. The contribution of differing forms of the GlyR to sensory processing in SDH and DDH is not understood. METHODS AND RESULTS: Here we compare fast inhibitory synaptic transmission in mouse (P17-37) SDH and DDH using patch-clamp electrophysiology in transverse spinal cord slices (L3-L5 segments, 23 degrees C). GlyR-mediated mIPSCs were detected in 74% (25/34) and 94% (25/27) of SDH and DDH neurons, respectively. In contrast, GABAAR-mediated mIPSCs were detected in virtually all neurons in both regions (93%, 14/15 and 100%, 18/18). Several Gly- and GABAAR properties also differed in SDH vs. DDH. GlyR-mediated mIPSC amplitude was smaller (37.1 +/- 3.9 vs. 64.7 +/- 5.0 pA; n = 25 each), decay time was slower (8.5 +/- 0.8 vs. 5.5 +/- 0.3 ms), and frequency was lower (0.15 +/- 0.03 vs. 0.72 +/- 0.13 Hz) in SDH vs. DDH neurons. In contrast, GABAAR-mediated mIPSCs had similar amplitudes (25.6 +/- 2.4, n = 14 vs. 25. +/- 2.0 pA, n = 18) and frequencies (0.21 +/- 0.08 vs. 0.18 +/- 0.04 Hz) in both regions; however, decay times were slower (23.0 +/- 3.2 vs. 18.9 +/- 1.8 ms) in SDH neurons. Mean single channel conductance underlying mIPSCs was identical for GlyRs (54.3 +/- 1.6 pS, n = 11 vs. 55.7 +/- 1.8, n = 8) and GABAARs (22.7 +/- 1.7 pS, n = 10 vs. 22.4 +/- 2.0 pS, n = 11) in both regions. We also tested whether the synthetic endocanabinoid, methandamide (methAEA), had direct effects on Gly- and GABAARs in each spinal cord region. MethAEA (5 muM) reduced GlyR-mediated mIPSC frequency in SDH and DDH, but did not affect other properties. Similar results were observed for GABAAR mediated mIPSCs, however, rise time was slowed by methAEA in SDH neurons. CONCLUSION: Together these data show that Gly- and GABAARs with clearly differing physiological properties and cannabinoid-sensitivity contribute to fast synaptic inhibition in mouse SDH and DDH.

Investigation of the expression of genes affecting cytomatrix active zone function in the amygdala in schizophrenia: effects of antipsychotic drugs.

The cytomatrix active zone (CAZ) is a specialized cellular structure regulating release of vesicles. We reported previously increased expression of three CAZ genes, piccolo, RIMS2 and RIMS3 in the amygdala in schizophrenia. This study determined the levels of gene and protein expression for components of the active zone including two additional CAZ genes in the amygdala from subjects with schizophrenia and non-psychiatric controls, as well as the effects of antipsychotic drugs. Whilst relative real-time PCR analysis did not identify significant change in the expression of six additional active zone genes, Western blot analysis showed increased piccolo and RIMS2 protein expression in the amygdala in schizophrenia. In vitro analysis suggests antipsychotic drug treatment was unlikely to have caused the changes in RIMS2, RIMS3 and piccolo expression observed in the amygdala in schizophrenia. Therefore, this study provides further evidence suggesting that piccolo, RIMS2, RIMS3, but not the entire components of the active zone are involved in the neurobiology of schizophrenia.

White matter neuron biology and neuropathology in schizophrenia.

Schizophrenia is considered a neurodevelopmental disorder as it often manifests before full brain maturation and is also a cerebral cortical disorder where deficits in GABAergic interneurons are prominent. Whilst most neurons are located in cortical and subcortical grey matter regions, a smaller population of neurons reside in white matter tracts of the primate and to a lesser extent, the rodent brain, subjacent to the cortex. These interstitial white matter neurons (IWMNs) have been identified with general markers for neurons [e.g., neuronal nuclear antigen (NeuN)] and with specific markers for neuronal subtypes such as GABAergic neurons. Studies of IWMNs in schizophrenia have primarily focused on their density underneath cortical areas known to be affected in schizophrenia such as the dorsolateral prefrontal cortex. Most of these studies of postmortem brains have identified increased NeuN+ and GABAergic IWMN density in people with schizophrenia compared to healthy controls. Whether IWMNs are involved in the pathogenesis of schizophrenia or if they are increased because of the cortical pathology in schizophrenia is unknown. We also do not understand how increased IWMN might contribute to brain dysfunction in the disorder. Here we review the literature on IWMN pathology in schizophrenia. We provide insight into the postulated functional significance of these neurons including how they may contribute to the pathophysiology of schizophrenia.