22941 results for "ega"

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• The Egyptian Collaborative Cardiac Genomics (ECCO-GEN) Project: Defining a Healthy Volunteer Cohort

  The integration of comprehensive genomic and phenotypic data from diverse ethnic populations offers unprecedented opportunities towards advancements in precision medicine and novel diagnostic technologies. Current reference genomic databases are not representative of the global human population, making variant interpretation challenging, especially in underrepresented populations such as the North African population. To address this, the Egyptian Collaborative Cardiac Genomics (ECCO-GEN) Project launched a study comprising 1000 individuals free of cardiovascular disease (CVD). Here, we present the first 391 Egyptian healthy volunteers (EHVols) recruited to establish a pilot phenotyped control cohort. All individuals underwent detailed clinical investigation, including cardiac MRI, and were sequenced using a targeted panel of 174 genes with reported roles in inherited cardiac conditions (ICC). We identified 1,262 variants in 27 cardiomyopathy genes of which 15.1% were not captured in current global and regional genetic reference databases (here: gnomAD and Great Middle Eastern (GME) Variome). The ECCO-GEN project aims at defining the genetic landscape of an understudied population and providing individual-level genetic and phenotypic data to support future studies in CVD and population genetics.

  Study EGAS00001004434

• SS18-SSX-mediated hijacking of BAF complexes drives synovial sarcoma

  Synovial sarcoma (SS) is defined by a recurrent t(x;18) chromosomal translocation, which produces the hallmark SS18-SSX oncogenic fusion. Incorporation of SS18-SSX into BAF complexes renders BAF complexes aberrant in two distinct manners: the addition of 78aa of SSX onto SS18, and concomitant loss of BAF47 assembly. However, the importance and functional contributions of each of these perturbations on BAF complex targeting and gene expression regulation remain unclear. Here we use an integrative set of genomic approaches in human cancer cell lines and primary tumor samples to define the mechanistic consequences of the SS18-SSX fusion oncoprotein. We find that SS18-SSX hijacks BAF complexes to broad polycomb domains to activate bivalent genes, driving a unique gene expression program distinct from other loss-of-function BAF complex malignancies. Importantly, restoration of BAF47 rescues enhancer activation but is dispensable for proliferative arrest in cell lines. These results demonstrate that gain-of-function SS18-SSX-mediated BAF complex targeting and gene activation is the driving event in SS, and present a mechanism by which distinct functions of BAF complexes can be co-opted to drive oncogenesis.

  Study EGAS00001002920

• Khoe-San genomes reveal unique variation and confirm deepest population divergence in Homo sapiens

  The southern African indigenous Khoe-San populations harbor the most divergent lineages of all living peoples. Exploring their genomes is key to understanding deep human history. We sequenced 25 full genomes from five Khoe-San populations, revealing many novel variants, that 25% of variants are unique to the Khoe-San, and that the Khoe-San group harbors the greatest level of diversity across the globe. In line with previous studies, we found several gene-regions with extreme values in genome-wide distributions, potentially caused by natural selection early in the modern human lineage and more recent in time. These gene-regions included immunity-, sperm-, brain-, diet- and muscle-related genes. When accounting for recent admixture, all Khoe-San groups display genetic diversity approaching the levels in other African groups and a reduction in effective population size starting around 100,000 years ago. Hence, all human groups show a reduction in effective population size commencing around the time of the Out-of-Africa migrations, which coincides with changes in the paleoclimate records, changes that potentially impacted all humans at the time.

  Study EGAS00001004459

• Kidney_transplant_nephrectomy_scRNAseq

  Single cell transcriptomics study of tissue from human kidney transplant nephrectomies Tissue is acquired from kidney transplant nephrectomies, homogenised and disaggregated to a single cell suspension prior to droplet encapsulation single cell RNAseq (10X protocol) or plate based single cell RNAseq (SS2 protocol). Human tissues, including the kidney are seeded with a tissue resident immune cell network throughout life. These cells may self renew in situ or be replaced by circulating precursors which enter the tissue in response to tissue specific niche and inflammatory signals. We are using single cell RNA sequencing of kidney transplant nephrectomy tissue to 1) understand the immune cell populations which are resident within the human kidney 2) identify which of these populations is donor or recipient derived. 3) Uncover the temporal dynamics of donor/recipient chimerism in the the human kidney following transplantation. 4) Understand transcriptional differences between organs removed for a variety of reasons (infection, chronic rejection, vascular emergencies) This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/

  Study EGAS00001003935

• Mutational bias in spermatogonia impacts the anatomy of regulatory sites in the human genome

  Mutation in the germline is the ultimate source of genetic variation, but little is known about the influence of germline chromatin structure on mutational processes. Using ATAC-seq, we profile the open chromatin landscape of human spermatogonia, the most proliferative cell-type of the germline, identifying transcription factor binding sites (TFBSs) and PRDM9-binding sites, a subset of which will initiate meiotic recombination. We observe an increase in rare structural variant (SV) breakpoints at PRDM9-bound sites, implicating meiotic recombination in the generation of structural variation. Many germline TFBSs, such as NRF, are also associated with increased rates of SV breakpoints, apparently independent of recombination. Singleton short insertions (>=5 bp) are highly enriched at TFBSs, particularly at sites bound by testis active TFs, and their rates correlate with those of structural variant breakpoints. Short insertions often duplicate the TFBS motif, leading to clustering of motif sites near regulatory regions in this male-driven evolutionary process. Increased mutation loads at germline TFBSs disproportionately affect neural enhancers with activity in spermatogonia, potentially altering neurodevelopmental regulatory architecture. Local chromatin structure in spermatogonia is thus pervasive in shaping both evolution and disease.

  Study EGAS00001005366

• Patient-derived neuroblastoma model system OHC-NB1

  Accurate disease modeling presents a bottleneck against effective translation of novel neuroblastoma therapies into the clinic. Recently, considerable intra-tumor genetic heterogeneity has been observed in neuroblastoma, which calls for preclinical models that reflect this feature. Flexibility in a testing platform is also desirable to support assessment of different endpoints and tumor cell characteristics. We present the novel neuroblastoma model OHC-NB1, propagated from a bone marrow metastasis from a patient with INRG stage M, MYCN-amplified neuroblastoma at first diagnosis. To model different aspects of the disease, several preclinical models were developed from the bone marrow aspirate: a tissue plastic-adherent cell line, a 3-dimensional (3D) spheroid culture, and cell line-derived xenografts that were subcutaneously passaged in mice. Typical aspects of MYCN-amplified neuroblastoma, such as MYCN amplification in double minutes, 1p deletion, 17q gain, and a diploid karyotype, are present in OHC-NB1 and persist in all culture types. Whole exome sequencing revealed intra-tumor heterogeneity in the bone marrow metastasis reflected in the culture models. The set of OHC-NB1 cultures with a genetically heterogeneous MYCN-amplified neuroblastoma background provide a flexible preclinical testing system that recapitulates important features of metastatic neuroblastoma.

  Study EGAS00001003031

• A Single-cell Atlas of Progressive TKI Resistance in Chronic Myeloid Leukemia

  High-dimensional scRNA seq and CyTOF were used to identify features predictive of treatment outcome at diagnosis. An optimal TKI response was characterised by erythroid lineage skewing of the CD34+ HSPC compartment. While TKI-resistant CP was reminiscent of a BC-like state, where HSPCs were enriched for inflammation, stemness and quiescence. We designed a machine-learning approach which assessed the prognostic potential of all 32 sub-populations of our scRNA seq dataset. LSCs and NK populations harboured the highest prognostic power at diagnosis. Within the LSCs, erythroid lineage priming and MYC activation were features of an optimal and poor TKI responses, respectively. With the NK cell compartment, apart from a higher abundance of NK cells in TKI optimal responders, a memory-like HLA-DR+ adaptive NK and KLRC1+ NK populations were hallmarks of an optimal and poor TKI responses, respectively. Mechanistically, both cell intrinsic and extrinsic mechanisms contributed towards the higher sensitivity of EPs to TKI therapy. In summary, our high-dimensional single-cell atlas of TKI resistance highlights pivotal transcriptional features associated with TKI-resistance disease, some of which have the potential to be exploited as biomarkers.

  Study EGAS00001005509

• Transcriptomes of human CD4+ T lymphocytes - Metabolic project

  Human CD4+ T cells are essential mediators of immune responses. By altering the mitochondrial and metabolic states, we defined metabolic requirements of human CD4+ T cells for in vitro activation, expansion, and effector function. T cell activation and proliferation were reduced by inhibiting oxidative phosphorylation, while early cytokine production was maintained by either OXPHOS or glycolytic activity. Glucose deprivation in the presence of mild mitochondrial stress markedly reduced all three T cell functions, contrasting the exposure to resveratrol, an antioxidant and sirtuin-1 activator, which specifically inhibited cytokine production and T cell proliferation, but not T cell activation. Conditions that inhibited T cell activation were associated with the downregulation of 2′,5′-oligoadenylate synthetase genes via interferon response pathways. Our findings indicate that T cell function is grossly impaired by stressors combined with nutrient deprivation, suggesting that correcting nutrient availability, metabolic stress and/or the function of T cells in these conditions will improve the efficacy of T cell-based therapies.

  Study EGAS00001005565

• Resequencing (MIPS) of candidate genes for Keratoconus (2020)

  In this study, we selected 34 candidate genes for KC based on previous Whole Exome Sequencing (WES) and the literature, and resequenced them in 745 KC patients and 810 ethnically matched controls. Data analysis was performed using the single variant association test as well as gene-based mutation burden and variance components tests. In our study, we detected enrichment of genetic variation across multiple gene-based tests for the genes COL2A1, COL5A1, TNXB, ZEB1 and ZNF469. The top hit in the Fisher’s exact test was obtained for a common variant in the COL12A1 gene. Interestingly, COL5A1, TNXB, ZNF469 and COL12A1 are all known Ehlers-Danlos Syndrome (EDS) genes. Though the co-occurrence of KC and EDS has been reported previously, this study is the first to demonstrate a consistent role of genetic variants in EDS genes in the etiology of KC. In conclusion, our data show a shared genetic etiology between KC and EDS, and clearly confirm the currently disputed role of ZNF469 in disease susceptibility for KC. Besides the role for EDS genes, we also confirm the previously reported involvement of genetic variation in ZEB1 in KC.

  Study EGAS00001004267

• Clonal Decomposition and DNA Replication States Defined by Scaled Single-Cell Genome Sequencing

  Accurate measurement of clonal genotypes, mutational processes, and replication states from individual tumor-cell genomes will facilitate improved understanding of tumor evolution. We have developed DLP+, a scalable single-cell whole-genome sequencing platform implemented using commodity instruments, image-based object recognition, and open source computational methods. Using DLP+, we have generated a resource of 51,926 single-cell genomes and matched cell images from diverse cell types including cell lines, xenografts, and diagnostic samples with limited material. From this resource we have defined variation in mitotic mis-segregation rates across tissue types and genotypes. Analysis of matched genomic and image measurements revealed correlations between cellular morphology and genome ploidy states. Aggregation of cells sharing copy number profiles allowed for calculation of single-nucleotide resolution clonal genotypes and inference of clonal phylogenies and avoided the limitations of bulk deconvolution. Finally, joint analysis over the above features defined clone-specific chromosomal aneuploidy in polyclonal populations.

  Study EGAS00001003190