Search Results - EGA European Genome-Phenome Archive

Single Cell DNA Methylation Analysis for Forensic Epigenetics

As part of the Epigenetic CHaracterization and Observation (ECHO) program, the Genomic Analysis Laboratory at the Salk Institute generated the DNA methylation profiles of certain PBMC cell types to determine the change in methylation levels before, during or after exposure to certain biological or chemical agents. Samples from individuals who either handled anthrax in controlled environments or who tested positive to MRSA, MSSA, HIV, COVID-19 or exposed to Flu virus or organophosphates, or control samples were used in single-nucleus methylation (snmC-seq) assays to quantify DNA methylation levels of cytosine residues of the DNA. Around 5-10% cytosine sites were sampled in the assay. Using computational analyses, regions in the genome differentially methylated in response to the exposure were identified. This information can be used to develop diagnostic tools to predict the type of infection or time since exposure.

Study phs003204

Disease-Linked Regulatory DNA Variants and Homeostatic Transcription Factors in Epidermis

The role of non-coding variants in polygenic skin disease and their connection to homeostatic transcription factors (TFs) in epidermis was investigated. Homeostatic TFs were identified by perturb-seq in differentiating keratinocytes, using either 10x or split-pool approaches to sequencing, with follow-up validation by siRNA and RNA-seq. TF binding events were profiled by population sampling Cleavage Under Targets & Release Using Nuclease (CUT&RUN), in which a random population of neonatal foreskin keratinocytes were assayed by CUT&RUN for homeostatic TFs under progenitor growth and differentiation conditions. Heterozygous alleles were identified from the TF binding data and examined for allele specific binding events (ASBs). ASBs were then compared with non-coding variants linked to skin disease. Variants with potentially pathogenic effects were identified. Promoters and high TF occupancy genomic regions were found to be "buffered" against variants causing ASBs.

Study phs003977

Transcriptome of human trophoblast stem cells derived from normal and HDP placentas

Hypertensive disorders of pregnancy (HDP) is a disease driven by abnormal placenta formation, which is a leading cause of maternal and fetal death. For investigation of genetic and epigenetic regulation of human trophoblast differentiation, we have previously established human trophoblast stem cells (hTSCs) from first-trimester placentas. Those hTSCs were able to differentiate into extravillous trophoblasts (EVTs) and syncytiotrophoblasts (STs), and their transcriptome was similar to that of cytotrophoblasts in human placenta. However, since HDP happens in the second half of pregnancy, the conventional hTSC derivation method was not enough to investigate the nature of HDP trophoblasts. In this analysis, we improved the derivation method and successfully established the hTSCs from normal and HDP term placentas after delivery. We performed RNA-seq of normal and HDP hTSCs, and HDP hTSCs recapitulated abnormalities in gene expression reported in HDP placentas.

Study JGAS000660

RNA sequencing of surgically removed lung adenocarcinoma afterwards treated with immune checkpoint inhibitors

Patients with lung adenocarcinoma (LUAD) from The Cancer Genome Atlas (TCGA) database were enrolled in the training cohort to establish a prognostic signature based on the expression of tumor-specific amino acid metabolism related genes. The established signature was further investigated against an original cohort, KCC-ICI, of chemotherapy combined with immune checkpoint inhibitors. The signature consisting of nine genes, KYNU, PSPH, PPAT, MIF, GCLC, ACAD8, TYRP1, ALDH2, and HDC, could effectively stratify the OS in LUAD patients. The KCC-ICI cohort confirmed the predictive ability of the established signature in the clinical response to immune checkpoint blockade therapy, which correlated with the infiltration of immune cells (e.g., T lymphocytes and nature killer cells). We discovered that the high signature risk score patients showed a significantly lower concentration of plasma-free ??-aminobutyric acid (AABA).

Study JGAS000675

The Formation and Propagation of Human Robertsonian Chromosomes

Robertsonian chromosomes are a type of variant chromosome found commonly in nature. Present in one in 800 humans, these chromosomes can underlie infertility, trisomies, and increased cancer incidence. Recognized cytogenetically for more than a century, their origins have remained mysterious. Recent advances in genomics have allowed us to assemble three human Robertsonian chromosomes completely. We identify a common breakpoint and epigenetic changes in centromeres that provide insight into the formation and propagation of common Robertsonian translocations. Further investigation of the assembled genomes of chimpanzee and bonobo highlights the structural features of the human genome that uniquely enable the specific crossover event that creates these chromosomes. Resolving the structure and epigenetic features of human Robertsonian chromosomes at a molecular level will pave the way to understanding how chromosomal structural variation occurs more generally, and how chromosomes evolve.

Study phs003920

Identification of a Type 1 Diabetes-Associated T Cell Receptor Repertoire Signature from the Human Peripheral Blood

Type 1 Diabetes (T1D) is a T-cell mediated disease with a strong immunogenetic HLA dependence. HLA allelic influence on the T cell receptor (TCR) repertoire shapes thymic selection and controls activation of diabetogenic clones, yet remains largely unresolved in T1D. We sequenced the circulating TCRβ chain repertoire from 2250 HLA-typed participants across three cross-sectional cohorts, including T1D individuals, and healthy related and unrelated controls. We found that HLA risk alleles show higher restriction of TCR repertoires in T1D individuals. We leveraged deep learning to identify T1D-associated TCR subsequence motifs that were also observed in independent TCR cohorts residing in pancreas-draining lymph nodes of T1D individuals. Collectively, our data demonstrate T1D-related TCR motif enrichment based on genetic risk, offering a potential metric for autoreactivity and groundwork for TCR-based diagnostics and therapeutics.

Study phs003979

End motifs analysis of circulating DNA from the plasma of patients with stage II-III breast cancer (n=50), stage I-III non-small cell lung cancer (n=56), metastatic colorectal cancer (mCRC) (n=15) and healthy individuals (n=37)..

We have developed an algorithm designed to discriminate cancer patients and healthy individuals based on cirDNA fragment end motif analysis assisted by machine learning, using data obtained from shallow whole genome sequencing (a method we call EMA). We applied EMA to cirDNA from the plasma of patients with stage II-III breast cancer, stage I-III non-small cell lung cancer, and metastatic colorectal cancer (mCRC). CirDNA from 158 individuals was prepared following the conventional double-stranded DNA library preparation (DSP). We also performed a single-stranded DNA library preparation (SSP) using mCRC patients and healthy control cirDNA, which allowed us to make the first ever end motif analysis in the literature which compares the use of DSP and SSP.

Study EGAS50000001319

ProstOmics: spatial and bulk multi-omics of prostate cancer

In this ERC-funded ProstOmics project we have used spatial and bulk multi-omics on fresh frozen prostate cancer samples to investigate cancer biology and find for biomarkers to improve patient treatment. All tissue material were collected from prostate cancer patients undergoing radical prostatectomy who had not received any prior cancer-specific treatment.Of the 498 prostate tissue samples (114 patients) included in our project, 176 samples (N=37 patients) have been analyzed with bulk transcriptomics (RNA-seq). Some of these 176 samples were also analyzed with spatial transcriptomics (n=32, N=8, Visium 10x RNA-seq) and DNA methylomics (n=96, N=24, array). All datasets include metadata for histopathological evaluation. Patient metadata include information of age at surgery, time (months) until reported relapse, pre-surgery PSA and post-surgery T-stage.

Study EGAS50000000413

Dynamic Evolution of Fibroblasts Revealed by Single Cell RNA Sequencing of Human Pancreatic Cancer

Understanding the constituents of the pancreatic ductal adenocarcinoma (PDAC) microenvironment may illuminate more efficacious targets for treating this aggressive malignancy. However, the compositional changes occurring in untreated and treated PDAC relative to both normal and inflamed pancreas have not been well characterized. To provide a more comprehensive understanding of the PDAC tumor microenvironment relative to the non-cancerous pancreas, we performed single-cell expression profiling (10X Genomics Chromium) on samples of upfront resectable PDAC, FOLFIRINOX-based treated PDAC, chronic pancreatitis, and normal pancreas specimens from 19 patients. Spatial gene expression profiling (10X Genomics Visium) was performed to gain additional insight into cell populations. Our analysis revealed that fibroblasts are central mediators of cell-cell communication in both inflamed and malignant settings and defined unique roles for these cell populations in different disease contexts.

Study phs003751

DNA methylation dynamics during early human development

DNA methylation is globally reprogrammed during mammalian preimplantation development, which has been well characterized in the mouse but not in other mammals. Here we report on the single base-resolution DNA methylome of human gametes and blastocysts. Near complete demethylation of the paternal genome was apparent, except for tandem repeat-containing CpG-rich regions, whereas the maternal genome was essentially resistant to replication-dependent global demethylation. The human oocyte methylome was characterized by a unique bimodal distribution of gene body methylation, a particular promoter methylation profile and a high proportion of hypomethylated transposable elements. Methylome and transcriptome comparisons between the human and mouse suggested species-specific regulation of many genes including the important DNA methylation regulators. Our findings are essential to understand the unique gene regulatory mechanisms during early human development and will facilitate preimplantation epigenetic diagnosis of human embryos.

Study JGAS000006

A capture methyl-seq protocol with improved efficiency and cost-effectiveness using pre-pooling and enzymatic conversion

The opportunities for sequencing-based methylome analysis of clinical samples are increasing. To reduce its cost and the amount of genomic DNA required for library preparation, we aimed to establish a capture methyl-seq protocol, which adopts pre-pooling of multiple libraries before hybridization capture and TET2/APOBEC-mediated conversion of unmethylated cytosine to thymine. We compared a publicly available dataset generated by the standard Agilent protocol of SureSelect XT Human Methyl-Seq Kit and our dataset obtained by our modified protocol, EMCap, that adopted sample pre-pooling and enzymatic conversion. We confirmed that the quality of DNA methylation data was comparable between the two datasets. As our protocol, EMCap, is more cost-effective and reduces the amount of input genomic DNA, it would serve as a better choice for clinical methylome sequencing.

Study JGAS000605

Controlling cell differentiation with precision through understanding the structure and dynamics of gene regulatory networks

We established a set of transgenic human ES cell lines that carry inducible expression gene cassette for singe transcriptional factor induction with Tet-ON system. Transcriptome data was obtained 48h after transgene induction by Microarray. We established inducible human ES lines about more than 700 genes, and achieved microarray analysis on 115 genes. Our data set has multiple characteristic properties; 1) the same platform across data set, 2) analyzed with dynamic cell status, 3) pre-determined initiation point on gene perturbation, 4)inducible in different cell status. In parallele, we also performed RNA sequenncig analysis on 435 transgene induced ES lines as well. 32 transgene induced transcriptome data were obtained from both Microarray and RNA sequencing, normalizing technical gaps between them. We hope those systematic data set to reveal transcriptional network structure and molecular mechanisms of cell differentiation.

Study JGAS000121

Genomics characterization of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare malignancy confined to the central nervous system (CNS). Despite low tendency of systemic dissemination, its prognosis is poor with median overall survival of 2?4 years. Due to its rarity, knowledge of genomic alterations underling PCNSL pathogenesis is severely limited. Here we performed whole-exome sequencing on 44 PCNSL and paired normal specimens, revealing high penetrance of nonsynonymous somatic mutations in PIM1 (95.5%), BTG2 (88.6%) and MYD88 (81.8%). Interestingly we found oncogenic mutations in GRB2, and this effect was cancelled when transformed cells are treated with inhibitors to downstream kinases MAP2K1/2. Further, when tumor cells carries MYD88 mutations, the same mutations were also found at low frequency in peripheral blood mononuclear cells (PBMNC), implying that MYD88 mutation?positive precancerous cells originate outside CNS and develop to lymphoma with additional genetic hits that fit the CNS environment.

Study JGAS000021

Mutational anysis of breast cancer stem cells

Exome sequences of breast cancer have been investigated for many patients. Recently it has been shown that there are intra-heterogeneity in tumor tissues. When the tumor cells were sequenced in bulk condition, only the major populations�� (clones��) mutations will be detected. Based on cancer stem theory, each populations�� cells are derived from each cancer stem cells, which their numbers are not so different among different clones. Here, we separated cancer cells into cancer stem cells and non-cancer stem cells exploiting cancer stem cell specific surface markers. By comping two groups�� mutation, we identified mutations, which were only detected in stem cell population. These mutations could be the mutations in cells of small size populations, and maybe the important mutations to understand the heterogeneity of tumor tissues, progression, and/or prediction for the outcome to therapies.

Study JGAS000304

DEPArray-based sorting of pure carcinoma and stromal populations from formalin-fixed paraffin-embedded (FFPE) tissues followed by shallow whole genome sequencing

To overcome the challenges of low DNA yields, degraded DNA by formalin fixation and diluted signal of genomic aberrations by non-carcinoma components in the heterogeneous FFPE samples, we isolated pure carcinoma and stromal cells using the DEPArray™ NxT system, a microchip-based digital sorter that allows isolation of pure, homogeneous subpopulations of cells from FFPE samples. We isolated pure carcinoma and stromal cell populations from 12 FFPE tissues, including tissues from 9 primary and metastatic breast cancer and 3 primary ovarian high-grade serous carcinomas. This was followed by downstream shallow whole genome sequencing (WGS) for copy number landscape profiling for 10 samples. Seven out of 10 samples (even some with low tumour content or of old age) produced good quality genomic data, detecting sCNA in all carcinoma population samples but not in the stromal populations.

Study EGAS50000001328

APOL1 Risk Variants Induce Metabolic Reprogramming of Podocytes in Patient-Derived Kidney Organoids

Apolipoprotein L1 (APOL1) high-risk genotypes G1 and G2 are responsible for the increased risk of chronic kidney disease (CKD) in the African-American population, especially in the presence of interferon gamma (IFN-γ). Here, we applied single cell transcriptomics on kidney organoids generated from patient-derived induced pluripotent stem cells (iPSCs) to model human APOL1 nephropathy. iPSCs were generated from fibroblasts of two patients with APOL1 nephropathy homozygous for G1 or G2 risk variants, and an isogenic control (G0) was created by gene correction. Kidney organoids were generated according to previously published protocol (Takasato M et al. Nat. Protoc. 2016) and treated with IFN-γ for two days to induce APOL1. Twenty-four hours after IFN-γ removal, treated organoids from all three lines that were cultured in parallel were harvested for single cell transcriptomics.

Study EGAS50000001223

A benchmark of DNA methylation deconvolution methods for tumoral fraction estimation using DecoNFlow

In cancer patients, circulating cell-free DNA (cfDNA) originates from both healthy and cancer cells, and the proportion of tumor-derived cfDNA serves as a surrogate marker of tumor burden. Tumoral cfDNA can be identified using patient-specific mutations or more general tumor-specific DNA methylation patterns that are preserved in cfDNA, enabling non-invasive cancer detection and monitoring. Accurately estimating tumor fractions remains challenging due to the heterogeneous mixture of cfDNA sources in body fluids. Computational DNA methylation deconvolution methods can address this by estimating tumoral fraction with or without reference methylomes. Here, we benchmarked 10 reference-based and 2 reference-free DNAm deconvolution tools and provide the data generated for this benchmarking, consisting of 10 neuroblastoma cell lines and one healthy cfDNA sample (pooled from 15 healthy cfDNA samples), profiled using cfRRBS.

Study EGAS50000001529

Multimodal epigenetic sequencing analysis of cell-free DNA identifies biomarkers for ALS diagnosis and progression

The role of the circulating epigenome in ALS remains understudied. We aim to develop diagnostic and prognostic blood-based biomarkers for Amyotrophic Lateral Sclerosis (ALS) by profiling methylome signatures in circulating cell-free DNA (cfDNA) in 20 sporadic ALS cases, 10 C9orf72-associated ALS cases, 10 asymptomatic C9orf72 expansion carriers, and 21 healthy controls using targeted enzymatic methyl-sequencing (EM-seq) of ~4 million CpG loci. We detected numerous differentially methylated genes, including several implicated in ALS risk and pathobiology, and integrated multiple epigenetic features with our Multimodal Epigenetic Sequencing Analysis (MESA) algorithm, achieving an ROC AUC of 0.91 and detecting ~70% of ALS cases at ~100% specificity. Methylation at a subset of loci also correlated with clinical progression and cerebrospinal-fluid neurofilament levels, supporting the potential of cfDNA-based biomarkers for ALS diagnosis and monitoring.

Study EGAS50000001267

Single-nucleus brain transcriptomics reveals microglia dysfunction in Multiple System Atrophy

Multiple System Atrophy (MSA) is a rare, age-related neurodegenerative disease that shares clinical and pathological features with Parkinson’s disease (PD) but presents a more devastating disease course. To elucidate the distinct cellular pathophysiology underlying multiple system atrophy (MSA) or Parkinson's disease (PD), we performed single-nucleus RNA sequencing on postmortem striatal brain tissue from 7 MSA and 12 PD patients, and 10 non-neurological cases. Using 10x Genomics Chromium Next GEM Single Cell 3' Reagent Kits v3.1, we isolated 130k nuclei covering all major cell types of the striatum. We performed state-of-the-art bioinformatic analyses on the data followed by orthogonal analyses to validate our findings. We identified a disease-specific activation of microglia cells distinguishing the two diseases and possibly explaining some of the detrimental effects observed in both.

Study EGAS50000001406

An ancient DNA perspective on the Russian Conquest of Yakutia

Yakut communities from northeastern Siberia inhabit some of the coldest environments on Earth preserving an extraordinary archaeological record. Their history was profoundly reshaped by the Russian conquest, which introduced cereals, pathogens and Christianity from 1632 CE. However, the biological impact of these transformations remains unknown. Here, we generated extensive ancient DNA data to elucidate contemporary changes in Yakut genomic diversity and oral microbiomes. We found Yakut origins tracing back to local populations that admixed with trans-Baikal groups migrating as the Great Mongol Empire spread. Despite the Russian conquest, the Yakut gene pool and oral microbiomes appeared largely stable, though smallpox strains distinct from those documented in Europe by ~1650 CE circulated. Marital practices generally maintained low consanguinity, with the exception of one female bearing the latest markers of traditional shamanism, who was the daughter of second-degree relatives.

Study EGAS50000001329

TenK10K Phase 1: Single Cell

Understanding the genetic basis of gene expression can shed light on the regulatory mechanisms underlying complex traits and diseases. Single-cell resolved measures of RNA levels and single-cell expression quantitative trait loci (sc-eQTLs) have revealed genetic regulation that drives sub-tissue cell states and types across diverse human tissues. Here, we describe the first phase of TenK10K, the largest- to-date dataset of matched whole-genome sequencing (WGS) and single-cell RNA-sequencing (scRNA-seq). We leverage scRNA-seq data from over 5 million cells across 28 immune cell types and matched WGS from 1,925 individuals. This provides power to detect associations between rare and low-frequency genetic variants that have largely been uncharacterised in their impact on cell-specific gene expression. We map the effects of both common and rare variants in a cell type specific manner using SAIGE-QTL.

Study EGAS50000001653

The function of circular RMST in neuroendocrine tumours

Circular RNA (circRNA) is a class of noncoding RNA with regulatory potentials. Its role in the transdifferentiation of prostate and lung adenocarcinoma into neuroendocrine prostate cancer (NEPC) and small cell lung cancer (SCLC) remains unexplored. Here we identified circRMST as an exceptionally abundant circRNA predominantly expressed in NEPC using total RNA-seq profiling of patient samples. In addition, circRMST is also abundantly expressed in SCLC. Functional studies using shRNA, siRNA, CRISPR-Cas13 and Cas9 consistently demonstrate that circRMST is essential for tumour growth and the expression of ASCL1, a master regulator of neuroendocrine fate. Mechanistically, circRMST physically interacts with lineage transcription factors NKX2-1 and SOX2. Loss of circRMST induces NKX2-1 protein degradation through autophagy-lysosomal pathway and alters the genomic binding of SOX2, collectively leading to the loss of ASCL1 transcription.

Study EGAS50000000897

Long-read sequencing of saliva collected and stablized at room temperature in Oragene devices on the PacBio Revio

Saliva collected in Oragene™ devices and extracted with Nanobind kits yields high‑molecular‑weight DNA suitable for PacBio HiFi whole‑genome sequencing, offering a convenient alternative to blood collection (“High-quality HMW DNA was obtained from all samples…”). Sequencing of paired saliva and blood samples on the Revio system produced comparable HiFi read lengths, yields, and 30–39× genome coverage. Methylation profiles were also highly similar, with minor differences attributable to small amounts of non‑human DNA present in saliva (“DNA extracted from saliva is typically ~75–95% human…”). Variant calling using PacBio WGS pipelines showed high concordance between saliva and blood from the same donor for both SNVs and structural variants. These results demonstrate that saliva enables reliable, high‑throughput HiFi sequencing workflows with performance equivalent to blood.

Study EGAS50000001666

Genetic landscape of pediatric Retinoblastoma

Retinoblastoma is a pediatric cancer of the developing retina. All retinoblastomas are believed to initiate with biallelic inactivation of the RB1 gene. To identify subsequent genetic lesions in retinoblastoma, we performed whole genome sequencing of tumor and normal DNA of 4 children with retinoblastoma and one matched orthotopic xenograft. Both alleles of RB1 were inactivated in the tumor samples. 3 of the patients had sporadic retinoblastoma and one patient had inherited retinoblastoma. Overall, there were few single nucleotide changes in coding regions of the genome and some of the tumors had few chromosomal lesions. There were very few new genetic lesions in the xenograft compared to the primary tumor. These data suggest that the genome in retinoblastoma is more stable than previously believed and there are relatively few recurrent genetic lesions in known cancer pathways other than the RB1 pathway.

Study EGAS00001000346

Cell-type, allelic and genetic signatures in the human pancreatic beta cell transcriptome

Pancreatic beta cells within the islets of Langerhans are centrally involved in the pathogenesis of both type 1 and type 2 diabetes. Describing the differentiated state of the human beta cell has been hampered so far by technical (low resolution microarrays) and biological limitations (whole islet preparations rather than isolated beta cells). We circumvent these by deep RNA sequencing of purified beta cells from 11 individuals, presenting here the first characterization of the human beta cell transcriptome. Additionally, we perform the first comparison of gene expression profiles between beta cells, whole islets (N=7) and beta cell depleted islet preparations (N=5), revealing thus beta cell specific expression signatures. Finally, we combine this with whole-genome sequencing data for 7 of our donors, describing here the first set of genetic variants controlling inter-individual variability in beta cell gene expression.

Study EGAS00001000442

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