scholarly journals Network effects of the neuropsychiatric 15q13.3 microdeletion on the transcriptome and epigenome in human induced neurons

2019 ◽  
Author(s):  
Siming Zhang ◽  
Xianglong Zhang ◽  
Shining Ma ◽  
Carolin Purmann ◽  
Kasey Davis ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Ribosome Biogenesis ◽  
Molecular Mechanisms ◽  
Association Studies ◽  
Neuropsychiatric Disorders ◽  
Chromatin Accessibility ◽  
Gene Copy ◽  
Genome Wide ◽  
Induced Neurons

AbstractHeterozygous deletions in the 15q13.3 region are associated with several neuropsychiatric disorders including autism, schizophrenia, and attention deficit hyperactivity disorder. Several genes within the 15q13.3 deletion region may play a role in neuronal dysfunction, based on association studies in humans and functional studies in mice, but the intermediate molecular mechanisms remain unknown. We analyzed the genome-wide effects of the 15q13.3 microdeletion on the transcriptome and epigenome. Induced pluripotent stem cell (iPSC) lines from three patients with the typical heterozygous 15q13.3 microdeletion and three sex-matched controls were generated and converted into induced neurons (iNs) using the neurogenin-2 induction method. We analyzed genome-wide gene expression using RNA-Seq, genome-wide DNA methylation using SeqCap-Epi, and genome-wide chromatin accessibility using ATAC-Seq, in both iPSCs and iNs. In both cell types, gene copy number change within the 15q13.3 microdeletion was accompanied by significantly decreased gene expression and no compensatory changes in DNA methylation or chromatin accessibility, supporting the model that haploinsufficiency of genes within the deleted region drives the disorder. Further, we observed global effects of the deletion on the transcriptome and epigenome, with the effects being cell type specific and occurring at discrete loci. Several genes and pathways associated with neuropsychiatric disorders and neuronal development were significantly altered, including Wnt signaling, ribosome biogenesis, DNA binding, and clustered protocadherins. This molecular systems analysis of a large neuropsychiatric microdeletion can also be applied to other brain relevant chromosomal aberrations to further our etiological understanding of neuropsychiatric disorders.

scholarly journals Genomic dissection of 43 serum urate-associated loci provides multiple insights into molecular mechanisms of urate control

2019 ◽  
Author(s):  
James Boocock ◽  
Megan Leask ◽  
Yukinori Okada ◽  
Hirotaka Matsuo ◽  
Yusuke Kawamura ◽  
...  
Keyword(s):  
Gene Expression ◽  
Molecular Mechanisms ◽  
Association Studies ◽  
Organic Anion ◽  
Serum Urate ◽  
Regulatory Function ◽  
Eqtl Analysis ◽  
Genome Wide Association Studies ◽  
Genome Wide ◽  
Causal Genes

AbstractSerum urate is the end-product of purine metabolism. Elevated serum urate is causal of gout and a predictor of renal disease, cardiovascular disease and other metabolic conditions. Genome-wide association studies (GWAS) have reported dozens of loci associated with serum urate control, however there has been little progress in understanding the molecular basis of the associated loci. Here we employed trans-ancestral meta-analysis using data from European and East Asian populations to identify ten new loci for serum urate levels. Genome-wide colocalization with cis-expression quantitative trait loci (eQTL) identified a further five new loci. By cis- and trans-eQTL colocalization analysis we identified 24 and 20 genes respectively where the causal eQTL variant has a high likelihood that it is shared with the serum urate-associated locus. One new locus identified was SLC22A9 that encodes organic anion transporter 7 (OAT7). We demonstrate that OAT7 is a very weak urate-butyrate exchanger. Newly implicated genes identified in the eQTL analysis include those encoding proteins that make up the dystrophin complex, a scaffold for signaling proteins and transporters at the cell membrane; MLXIP that, with the previously identified MLXIPL, is a transcription factor that may regulate serum urate via the pentose-phosphate pathway; and MRPS7 and IDH2 that encode proteins necessary for mitochondrial function. Trans-ancestral functional fine-mapping identified six loci (RREB1, INHBC, HLF, UBE2Q2, SFMBT1, HNF4G) with colocalized eQTL that contained putative causal SNPs (posterior probability of causality > 0.8). This systematic analysis of serum urate GWAS loci has identified candidate causal genes at 19 loci and a network of previously unidentified genes likely involved in control of serum urate levels, further illuminating the molecular mechanisms of urate control.Author SummaryHigh serum urate is a prerequisite for gout and a risk factor for metabolic disease. Previous GWAS have identified numerous loci that are associated with serum urate control, however, only a small handful of these loci have known molecular consequences. The majority of loci are within the non-coding regions of the genome and therefore it is difficult to ascertain how these variants might influence serum urate levels without tangible links to gene expression and / or protein function. We have applied a novel bioinformatic pipeline where we combined population-specific GWAS data with gene expression and genome connectivity information to identify putative causal genes for serum urate associated loci. Overall, we identified 15 novel serum urate loci and show that these loci along with previously identified loci are linked to the expression of 44 genes. We show that some of the variants within these loci have strong predicted regulatory function which can be further tested in functional analyses. This study expands on previous GWAS by identifying further loci implicated in serum urate control and new causal mechanisms supported by gene expression changes.

scholarly journals A novel quantile regression approach for eQTL discovery

2016 ◽  
Author(s):  
Xiaoyu Song ◽  
Gen Li ◽  
Iuliana Ionita-Laza ◽  
Ying Wei
Keyword(s):  
Gene Expression ◽  
Genetic Variation ◽  
Linear Regression ◽  
Genetic Variants ◽  
Molecular Mechanisms ◽  
Association Studies ◽  
Expression Level ◽  
Special Focus ◽  
Genome Wide Association Studies ◽  
Genome Wide

AbstractOver the past decade, there has been a remarkable improvement in our understanding of the role of genetic variation in complex human diseases, especially via genome-wide association studies. However, the underlying molecular mechanisms are still poorly characterized, impending the development of therapeutic interventions. Identifying genetic variants that influence the expression level of a gene, i.e. expression quantitative trait loci (eQTLs), can help us understand how genetic variants influence traits at the molecular level. While most eQTL studies focus on identifying mean effects on gene expression using linear regression, evidence suggests that genetic variation can impact the entire distribution of the expression level. Indeed, several studies have already investigated higher order associations with a special focus on detecting heteroskedasticity. In this paper, we develop a Quantile Rank-score Based Test (QRBT) to identify eQTLs that are associated with the conditional quantile functions of gene expression. We have applied the proposed QRBT to the Genotype-Tissue Expression project, an international tissue bank for studying the relationship between genetic variation and gene expression in human tissues, and found that the proposed QRBT complements the existing methods, and identifies new eQTLs with heterogeneous effects genome-wideacross different quantile levels. Notably, we show that the eQTLs identified by QRBT but missed by linear regression are more likely to be tissue specific, and also associated with greater enrichment in genome-wide significant SNPs from the GWAS catalog. An R package implementing QRBT is available on our website.

scholarly journals In utero Bisphenol A Exposure Is Linked with Sex Specific Changes in the Transcriptome and Methylome of Human Amniocytes

2019 ◽  
Vol 105 (2) ◽  
pp. 453-467
Author(s):  
Amita Bansal ◽  
Nicole Robles-Matos ◽  
Paul Zhiping Wang ◽  
David E Condon ◽  
Apoorva Joshi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Bisphenol A ◽  
Gestational Age ◽  
Molecular Mechanisms ◽  
In Utero ◽  
Metabolic Dysfunction ◽  
Altered Expression ◽  
Obesity And Diabetes ◽  
Genome Wide

Abstract Context Prenatal exposure to bisphenol A (BPA) is linked to obesity and diabetes but the molecular mechanisms driving these phenomena are not known. Alterations in deoxyribonucleic acid (DNA) methylation in amniocytes exposed to BPA in utero represent a potential mechanism leading to metabolic dysfunction later in life. Objective To profile changes in genome-wide DNA methylation and expression in second trimester human amniocytes exposed to BPA in utero. Design A nested case-control study was performed in amniocytes matched for offspring sex, maternal race/ethnicity, maternal age, gestational age at amniocentesis, and gestational age at birth. Cases had amniotic fluid BPA measuring 0.251 to 23.74 ng/mL. Sex-specific genome-wide DNA methylation analysis and RNA-sequencing (RNA-seq) were performed to determine differentially methylated regions (DMRs) and gene expression changes associated with BPA exposure. Ingenuity pathway analysis was performed to identify biologically relevant pathways enriched after BPA exposure. In silico Hi-C analysis identified potential chromatin interactions with DMRs. Results There were 101 genes with altered expression in male amniocytes exposed to BPA (q < 0.05) in utero, with enrichment of pathways critical to hepatic dysfunction, collagen signaling and adipogenesis. Thirty-six DMRs were identified in male BPA-exposed amniocytes and 14 in female amniocyte analysis (q < 0.05). Hi-C analysis identified interactions between DMRs and 24 genes with expression changes in male amniocytes and 12 in female amniocytes (P < 0.05). Conclusion In a unique repository of human amniocytes exposed to BPA in utero, sex-specific analyses identified gene expression changes in pathways associated with metabolic disease and novel DMRs with potential distal regulatory functions.

scholarly journals Unique and assay specific features of NOMe-, ATAC- and DNase I-seq data

2019 ◽  
Vol 47 (20) ◽  
pp. 10580-10596 ◽  
Author(s):  
Karl J V Nordström ◽  
Florian Schmidt ◽  
Nina Gasparoni ◽  
Abdulrahman Salhab ◽  
Gilles Gasparoni ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Experimental Design ◽  
Chromatin Accessibility ◽  
Dnase I ◽  
Open Chromatin ◽  
Functional Interpretation ◽  
Genome Wide ◽  
Show Evidence

Abstract Chromatin accessibility maps are important for the functional interpretation of the genome. Here, we systematically analysed assay specific differences between DNase I-seq, ATAC-seq and NOMe-seq in a side by side experimental and bioinformatic setup. We observe that most prominent nucleosome depleted regions (NDRs, e.g. in promoters) are roboustly called by all three or at least two assays. However, we also find a high proportion of assay specific NDRs that are often ‘called’ by only one of the assays. We show evidence that these assay specific NDRs are indeed genuine open chromatin sites and contribute important information for accurate gene expression prediction. While technically ATAC-seq and DNase I-seq provide a superb high NDR calling rate for relatively low sequencing costs in comparison to NOMe-seq, NOMe-seq singles out for its genome-wide coverage allowing to not only detect NDRs but also endogenous DNA methylation and as we show here genome wide segmentation into heterochromatic B domains and local phasing of nucleosomes outside of NDRs. In summary, our comparisons strongly suggest to consider assay specific differences for the experimental design and for generalized and comparative functional interpretations.

Genome-wide analysis reveals dynamic epigenomic differences in soybean response to low-phosphorus stress

2019 ◽  
Author(s):  
Shanshan Chu ◽  
Kaiye Yu ◽  
Lingling Lv ◽  
Xiangqian Zhang ◽  
Chongyuan Sun ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Molecular Mechanisms ◽  
Transcriptional Level ◽  
Small Interfering Rnas ◽  
Regulatory Relationship ◽  
Transcription Analysis ◽  
Genome Wide ◽  
Transcriptional Alterations ◽  
Methylome Analysis

Abstract Background: Phosphorus ( P ) is an essential nutrient for plant growth and metabolism, and low-P stress has a significant limiting effect on crop yield and quality. Although the molecular mechanisms of the transcriptional level responsible for the low-P stress response have been studied in detail, the underlying epigenetic mechanisms in gene regulation remain largely unknown. Results: In this study, we evaluated the changes in DNA methylation, gene expression and small interfering RNAs (siRNAs) abundance genome-wide in response to low-P stress in two representative soybean genotypes with different P-efficiencies. The methylome analysis revealed that the soybean genome presents ~67.54% mCG (mCG/CG), ~44.57% mCHG (mCHG/CHG) and ~3.79% mCHH (mCHH/CHH), respectively. The DNA methylation levels were slightly higher under low-P stress in both genotypes. Integral methylation and transcription analysis suggested a complex regulatory relationship between DNA methylation and gene expression that may be associated with the type, region, and extent of methylation. Association analysis of low-P-induced differential methylation and gene expression showed that transcriptional alterations of a small part of genes were associated with methylation changes. Dynamic methylation alterations in transposable element ( TE ) regions in the CHH methylation context correspond with changes in the amount of siRNA under low-P conditions, indicating an important role of siRNAs in modulating TE activity by guiding CHH methylation in TE regions. Conclusions: This is the first time to investigate low-P-induced methylome alterations and their relationship with changes of gene expression and siRNA abundance in soybean. The results in our study could help to elucidate the epigenetic regulation mechanisms governing the responses of plants to abiotic stresses.

scholarly journals Genome-Wide Analysis Reveals Dynamic Epigenomic Differences in Soybean Response to Low-Phosphorus Stress

2020 ◽  
Vol 21 (18) ◽  
pp. 6817
Author(s):  
Shanshan Chu ◽  
Xiangqian Zhang ◽  
Kaiye Yu ◽  
Lingling Lv ◽  
Chongyuan Sun ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Molecular Mechanisms ◽  
Transcriptional Level ◽  
Small Interfering Rnas ◽  
Regulatory Relationship ◽  
Transcription Analysis ◽  
Genome Wide ◽  
Low Phosphorus ◽  
Transcriptional Alterations

Low-phosphorus (low-P) stress has a significant limiting effect on crop yield and quality. Although the molecular mechanisms of the transcriptional level responsible for the low-P stress response have been studied in detail, the underlying epigenetic mechanisms in gene regulation remain largely unknown. In this study, we evaluated the changes in DNA methylation, gene expression and small interfering RNAs (siRNAs) abundance genome-wide in response to low-P stress in two representative soybean genotypes with different P-efficiencies. The DNA methylation levels were slightly higher under low-P stress in both genotypes. Integrative methylation and transcription analysis suggested a complex regulatory relationship between DNA methylation and gene expression that may be associated with the type, region, and extent of methylation. Association analysis of low-P-induced differential methylation and gene expression showed that transcriptional alterations of a small part of genes were associated with methylation changes. Dynamic methylation alterations in transposable element (TE) regions in the CHH methylation context correspond with changes in the amount of siRNA under low-P conditions, indicating an important role of siRNAs in modulating TE activity by guiding CHH methylation in TE regions. Together, these results could help to elucidate the epigenetic regulation mechanisms governing the responses of plants to abiotic stresses.

scholarly journals Integrative genomic strategies applied to a lymphoblast cell line model reveal specific transcriptomic signatures associated with clozapine response

2020 ◽  
Author(s):  
SAJ de With ◽  
APS Ori ◽  
T Wang ◽  
SL Pulit ◽  
E Strengman ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Adverse Effects ◽  
Drug Targets ◽  
Molecular Mechanisms ◽  
Disease Risk ◽  
Density Lipoprotein ◽  
Expression Levels ◽  
Genome Wide ◽  
Gene Expression Levels

AbstractClozapine is an important antipsychotic drug. However, its use is often accompanied by metabolic adverse effects and, in rare instances, agranulocytosis. The molecular mechanisms underlying these adverse events are unclear. To gain more insights into the response to clozapine at the molecular level, we exposed lymphoblastoid cell lines (LCLs) to increasing concentrations of clozapine and measured genome-wide gene expression and DNA methylation profiles. We observed robust and significant changes in gene expression levels due to clozapine (n = 463 genes at FDR < 0.05) affecting cholesterol and cell cycle pathways. At the level of DNA methylation, we find significant changes upstream of the LDL receptor, in addition to global enrichments of regulatory, immune and developmental pathways. By integrating these data with human tissue gene expression levels obtained from the Genotype-Tissue Expression project (GTEx), we identified specific tissues, including liver and several tissues involved in immune, endocrine and metabolic functions, that clozapine treatment may disproportionately affect. Notably, differentially expressed genes were not enriched for genome-wide disease risk of schizophrenia or for known psychotropic drug targets. However, we did observe a nominally significant association of genetic signals related to total cholesterol and low-density lipoprotein levels. Together, these results shed light on the biological mechanisms through which clozapine functions. The observed associations with cholesterol pathways, its genetic architecture and specific tissue effects may be indicative of the metabolic adverse effects observed in clozapine users. LCLs may thus serve as a useful tool to study these molecular mechanisms further.

scholarly journals Unique and assay specific features of NOMe-, ATAC- and DNase I-seq data

2019 ◽  
Author(s):  
Karl JV Nordström ◽  
Florian Schmidt ◽  
Nina Gasparoni ◽  
Abdulrahman Salhab ◽  
Gilles Gasparoni ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Chromatin Accessibility ◽  
Dnase I ◽  
Open Chromatin ◽  
Functional Interpretation ◽  
Genome Wide ◽  
Show Evidence

AbstractChromatin accessibility maps are important for the functional interpretation of the genome. Here, we systematically analysed assay specific differences between DNase I-Seq, ATAC-Seq and NOMe-Seq in a side by side experimental and bioinformatic setup. We observe that most prominent nucleosome depleted regions (NDRs, e.g. in promoters) are roboustly called by all three or at least two assays. However we also find a high proportion of assay specific NDRs that are often “called” by only one of the assays. We show evidence that these assay specific NDRs are indeed genuine open chromatin sites and contribute important information for accurate gene expression prediction. While technically ATAC-Seq and DNAse I-Seq provide a high NDR calling rate for relatively low sequencing costs in comparison to NOMe-Seq, NOMe-Seq singles out as it provides a multitude of information: it allows to not only detect NDRs but also endogenous DNA methylation, genome wide segmentation into heterochromatic A/B domains and local phasing of nucleosomes outside of NDRs. In summary our comparison strongly suggest to consider assay specific differences for the experimental desgin and for generalized and comparative functional interpretations.

scholarly journals Reversible Epigenetic Alterations Regulate Class I HLA Loss in Prostate Cancer

2021 ◽  
Author(s):  
Tamara Rodems ◽  
Erika Henninger ◽  
Charlotte Stahlfeld ◽  
Cole Gilsdorf ◽  
Kristin Carlson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Prostate Cancer ◽  
Dna Methylation ◽  
Tumor Cells ◽  
Molecular Mechanisms ◽  
Hla Class I ◽  
Chromatin Accessibility ◽  
Class I ◽  
Immune Recognition ◽  
Hdac Inhibition

Abstract Downregulation of HLA class I (HLA-I) impairs immune recognition and surveillance in prostate cancer and may underlie the ineffectiveness of checkpoint blockade. However, the molecular mechanisms regulating HLA-I loss in prostate cancer have not been fully explored. Here, we conducted a comprehensive analysis of HLA-I genomic, epigenomic and gene expression alterations in primary and metastatic human prostate cancer. Loss of HLA-I gene expression was associated with repressive chromatin states including DNA methylation, histone H3 tri-methylation at lysine 27, and reduced chromatin accessibility. Pharmacological DNMT and HDAC inhibition decreased DNA methylation and increased H3 lysine 27 acetylation and resulted in re-expression of HLA-I on the surface of tumor cells. Re-expression of HLA-I on LNCaP cells by DNMT and HDAC inhibition increased activation of co-cultured PSMA27-38-specific CD8+ T-cells. Methylated HLA-I was detected in HLA-Ilow circulating tumor cells (CTCs), which may serve as a biomarker for identifying patients who would benefit from epigenetic targeted therapies.

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