Project description:Schizophrenia-associated anomalies in gene expression in postmortem brain are caused by a combination of genetic and environmental influences. Given the small effect size of common variants it is likely that we may only see the combined impact of some of these at the pathway level in small postmortem studies. However, at the gene level we will see more impact from common environmental risk factors mediated by influential epigenomic modifiers. In this study we examine changes in cortical gene expression to identify regulatory interactions and networks associated with the disorder. Gene expression analysis in post-mortem prefrontal dorsolateral cortex (BA 46) (n=74 matched pairs of schizophrenia, schizoaffective and control samples) was performed using Illumina HT12 gene expression microarrays. Significant gene interaction networks were identified for differentially expressed genes in pathways of neurodevelopmental and oligodendrocyte function.
Project description:The existence of repressive and durable chromatin assemblies along gene promoters or networks, especially in the brain, is of theoretical and therapeutic relevance in a subset of individuals diagnosed with schizophrenia who experience a chronic, persistent, and treatment-resistant trajectory. We used chromatin immunoprecipitation followed by deep sequencing (ChIP-Seq) to generate an epigenomic map that includes differential sites occupied by di-methylated lysine 9 of histone 3 (H3K9me2), a repressive modification that is yet unexplored in human postmortem brain tissue. We have discovered over 150 significantly differential promoter sites in the postmortem prefrontal cortex tissue of individuals diagnosed with schizophrenia (n=15) when compared to controls (n=15). Potentially dysregulated gene categories include postsynaptic proteins, processing enzymes (for proproteins, lipids, and oxidative stress), cadherin family genes, the complement system, and peptide hormones. Ten genes with significantly increased or decreased H3K9me2 promoter occupation were selected through statistical analysis, function, or previous GWAS association, and qRT-PCR was performed on an extended sample of postmortem brain tissue, adding an additional 17 controls, 7 individuals with schizophrenia, and 19 individuals with bipolar samples (n=32 control, 22 schizophrenia, 19 bipolar). This approach revealed that mRNA expression levels correlated with chromatin modification levels in eight of ten selected genes, and mRNA expression in the total sample could be predicted by the occupancy of H3K9me2. Utilization of this method and replication in a larger sample open a pathway to durable and restrictive epigenomic assemblies whose accumulation across the lifespan of individuals diagnosed with schizophrenia may explain treatment resistance, and advance therapeutic options.
Project description:<p>Schizophrenia is a common mental illness. It is a complex disorder with many symptoms and cognitive impairments. Despite extensive study, the molecular mechanisms of this disease are still unknown. Present time studies on the lipid composition of the human brain are extremely fragmented. Of the possible levels of molecular analysis involving gene expression at the RNA or protein level, and the representation of polar metabolites and lipids, the latter seem to us to be the most promising now. We chose lipids as representative data of the pathogenic mechanism because they are the main structural components of brain cell tissue. The dataset provided unique samples of lipid LC-MS profiles of post-mortem human brains. Samples include not only healthy individuals but also patients with schizophrenia.</p>
Project description:Recent studies suggest that genetic and environmental factors do not account for all the schizophrenia risk and epigenetics also plays a role in disease susceptibility. DNA methylation is a heritable epigenetic modification that can regulate gene expression. Genome-Wide DNA methylation analysis was performed on post-mortem human brain tissue from 24 patients with schizophrenia and 24 unaffected controls. DNA methylation was assessed at over 485 000 CpG sites using the Illumina Infinium Human Methylation450 Bead Chip. After adjusting for age and post-mortem interval (PMI), 4 641 probes corresponding to 2 929 unique genes were found to be differentially methylated. Of those genes, 1 291 were located in a CpG island and 817 were in a promoter region. These include NOS1, AKT1, DTNBP1, DNMT1, PPP3CC and SOX10 which have previously been associated with schizophrenia. More than 100 of these genes overlap with a previous DNA methylation study of peripheral blood from schizophrenia patients in which 27 000 CpG sites were analysed. Unsupervised clustering analysis of the top 3 000 most variable probes revealed two distinct groups with significantly more people with schizophrenia in cluster one compared to controls (p = 1.74x10-4). The first cluster was composed of 88% of patients with schizophrenia and only 12% controls while the second cluster was composed of 27% of patients with schizophrenia and 73% controls. These results strongly suggest that differential DNA methylation is important in schizophrenia etiology and add support for the use of DNA methylation profiles as a future prognostic indicator of schizophrenia Genome-Wide DNA methylation analysis was performed on post-mortem human brain tissue from 24 patients with schizophrenia and 24 unaffected controls. DNA methylation was assessed at over 485 000 CpG sites using the Illumina Infinium Human Methylation450 Bead Chip.
Project description:Recent studies suggest that genetic and environmental factors do not account for all the schizophrenia risk and epigenetics also plays a role in disease susceptibility. DNA methylation is a heritable epigenetic modification that can regulate gene expression. Genome-Wide DNA methylation analysis was performed on post-mortem human brain tissue from 24 patients with schizophrenia and 24 unaffected controls. DNA methylation was assessed at over 485 000 CpG sites using the Illumina Infinium Human Methylation450 Bead Chip. After adjusting for age and post-mortem interval (PMI), 4 641 probes corresponding to 2 929 unique genes were found to be differentially methylated. Of those genes, 1 291 were located in a CpG island and 817 were in a promoter region. These include NOS1, AKT1, DTNBP1, DNMT1, PPP3CC and SOX10 which have previously been associated with schizophrenia. More than 100 of these genes overlap with a previous DNA methylation study of peripheral blood from schizophrenia patients in which 27 000 CpG sites were analysed. Unsupervised clustering analysis of the top 3 000 most variable probes revealed two distinct groups with significantly more people with schizophrenia in cluster one compared to controls (p = 1.74x10-4). The first cluster was composed of 88% of patients with schizophrenia and only 12% controls while the second cluster was composed of 27% of patients with schizophrenia and 73% controls. These results strongly suggest that differential DNA methylation is important in schizophrenia etiology and add support for the use of DNA methylation profiles as a future prognostic indicator of schizophrenia
Project description:Schizophrenia is a complex and severe neuropsychiatric disorder, with a wide range of debilitating symptoms. Several aspects of its multifactorial complexity are still unknown, and some are accepted to be an early developmental deficiency with a more specifically neurodevelopmental origin. Understanding timepoints of disturbances during neural cell differentiation processes could lead to an insight into the development of the disorder. In this context, human brain organoids and neural cells differentiated from patient-derived induced pluripotent stem cells are of great interest as a model to study the developmental origins of the disease. Here we evaluated the differential expression of proteins of schizophrenia patient-derived neural progenitors, early neurons, and brain organoids. Using bottom-up shotgun proteomics with a label-free approach for quantitative analysis. Multiple dysregulated proteins were found in pathways related to synapses, in line with postmortem tissue studies of schizophrenia patients. However, organoids and immature neurons exhibit impairments in pathways never before found in patient-derived induced pluripotent stem cell studies, such as spliceosomes and amino acid metabolism. In conclusion, here we provide comprehensive, large-scale, protein-level data that may uncover underlying mechanisms of the developmental origins of schizophrenia.
Project description:We investigated the transcriptome of dentate gyrus (DG) granule cells in postmortem hippocampus from 79 subjects with mental illness (schizophrenia, bipolar disorder, major depression) or non-psychiatric controls.
Project description:We used microarrays to detail the global program of gene expression underlying Parkinson's disease Experiment Overall Design: Substantia nigra tissue from postmortem brain of normal and Parkinson disease patients were used for RNA extraction and hybridization on Affymetrix microarrays: 9 replicates for the controls and 16 replicates for the Parkinson's disease patients were used. Both cohorts included males and females.