Search Results - EGA European Genome-Phenome Archive

Knoll et al Identification of drug candidates targeting monocyte reprogramming in people living with HIV

Introduction People living with HIV (PLHIV) are characterized by functional reprogramming of innate immune cells even after long-term antiretroviral therapy (ART). In order to assess technical feasibility of omics technologies for application to larger cohorts, we compared multiple omics layers. Methods Bulk and single-cell transcriptomics, flow cytometry, proteomics, chromatin landscape analysis by ATAC-seq as well as ex vivo drug stimulation was performed in a small number of blood samples derived from PLHIV and healthy controls from the 200-HIV cohort study. Results Single-cell RNA-seq analysis revealed that most immune cells in peripheral blood of PLHIV are altered in their transcriptomes and that a specific functional monocyte state previously described in acute HIV infection is still existing in PLHIV while other monocyte cell states are only occurring acute infection. Moreover, a reverse transcriptome approach on a rather small number of PLHIV was sufficient to identify drug candidates for reversing the transcriptional phenotype of monocytes in PLHIV. Discussion These scientific findings and technological advancements for clinical application of single-cell transcriptomics form the basis for the larger 2000-HIV multicenter cohort study on PLHIV, for which a combination of bulk and single-cell transcriptomics will be included as the leading technology to determine disease endotypes in PLHIV and to predict disease trajectories and outcomes.

Study EGAS00001007460

Epigenomics of Human CD8 T cell Differentiation and Aging

The efficacy of the adaptive immune response declines dramatically with age, but the cell-intrinsic mechanisms driving the changes characteristic of immune aging in humans remain poorly understood. One hallmark of immune aging is the loss of self-renewing naive cells and the accumulation of differentiated but dysfunctional cells within the CD8 T cell compartment. Using ATAC-seq, we first inferred the transcription factor binding activities that maintain the naive and central and effector memory CD8 T cell states in young adults. Integrating our results with RNA-seq, we determined that BATF, ETS1, Eomes, and Sp1 govern transcription networks associated with specific CD8 T cell subset properties, including activation and proliferative potential. Extending our analysis to aged humans, we found that the differences between memory and naive CD8 T cells were largely preserved across age, but that naive and central memory cells from older individuals exhibited a shift toward a more differentiated pattern of chromatin openness. Additionally, aged naive cells displayed a loss in chromatin openness at gene promoters, a phenomenon that appears to be due largely to a loss in binding by NRF1, leading to a marked drop-off in the ability of the naive cell to initiate transcription of mitochondrial genes. Our findings identify BATF- and NRF1-driven gene regulation as targets for delaying CD8 T cell aging and restoring T cell function.

Study phs001187

Single cell transcriptomics of hESC-derived midbrain dopaminergic neurons generated by a new human development-based protocol

Recent advances in stem cell technologies provide new opportunities for regenerative medicine and Parkinson’s disease modelling. However, the precise composition and quality of human embryonic stem cell (hESC)-derived preparations at the single cell level, compared to endogenous brain standards, remains to be determined. In addition, multiple developmental pathways important for midbrain dopaminergic (mDA) neuron development remain to be implemented in hESCs. Here we use mouse developmental knowledge and human single cell RNA-sequencing (scRNA-seq) data to generate a new development-based protocol to differentiate hESCs into mDA neurons. We found that Laminin 511, dual WNT activation with CHIR99021 and WNT5A, together with FGF8b, improved different aspects of midbrain patterning. Moreover, mDA neurogenesis and differentiation were enhanced by activation of liver X receptors and inhibition of fibroblast growth factor signaling. Analysis of hESC-derived midbrain cultures by scRNA-seq revealed multiple hESC-derived clusters, which resembled those in the endogenous human ventral midbrain. Moreover, high quality mDA neurons were detected and found to progressively acquire functionality in vitro. Thus, we hereby provide a hESC differentiation protocol that recapitulates several aspects of endogenous mDA neuron development, and a strategy to determine cell composition and quality of hESC-derived preparations that can be useful for disease modeling and cell therapy.

Study EGAS00001006313

Control of Focal Adhesion Kinase Activation by RUNX1-regulated miRNAs in high-risk AML

We recently described a 16-gene expression signature for improved risk stratification of acute myeloid leukemia (AML) patients called the AML Prognostic Score (APS). A subset of APS high-risk AML patients showed increased levels of focal adhesion kinase (FAK), encoded by the Protein Tyrosine Kinase 2 (PTK2) gene, which was correlated with RUNX1 mutations. RUNX1 mutant cells are more sensitive to PTK2 inhibitors. As we were not able to detect RUNX1 binding sites in the PTK2 promoter, we hypothesized that RUNX1 might regulate micro(mi)RNAs that repress PTK2, such that loss-of-function RUNX1 mutations would result in reduced miRNA expression and derepression of PTK2. Examination of paired RNA-seq and miRNA-seq data from 301 AML cases revealed two miRNAs that positively correlated with RUNX1 expression, contained RUNX1 binding sites in their promoters and were predicted to target PTK2. We show that the hsa-let7a-2-3p and hsa-miR-135a-5p promoters are regulated by RUNX1, and that PTK2 is a direct target of both miRNAs. Even in the absence of RUNX1 mutations, hsa-let7a-2-3p and hsa-miR-135a-5p regulate PTK2 expression, and reduced expression of these two miRNAs sensitizes AML cells to PTK2 inhibition. These data explain how RUNX1 regulates PTK2, and identify potential miRNA biomarkers for targeting AML with PTK2 inhibitors.

Study EGAS00001006491

Patient-tailored design for selective co-inhibition of leukemic cell subpopulations

The extensive primary and secondary drug resistance in many cancer types requires rational approaches to design personalized and selective combinatorial therapies that do not only show synergistic effect in overall cancer cell killing but also result in minimal toxic side effects on non-malignant cells. To address the combinatorial explosion in the number of relevant combinations, we implemented a machine learning approach that prioritizes patient-customized drug combinations with a desired synergy-efficacy-toxicity balance by combining single-cell RNA-sequencing with ex vivo single-agent testing in scarce patient-derived primary cells. When applied to two diagnostic and two refractory AML patient cases, each with a different genetic background, our integrated approach accurately predicted patient-specific combinations that were shown to result not only in synergistic cancer cell co-inhibition but were also capable of targeting specific AML cell subpopulations that emerge in differing stages of disease pathogenesis or treatment regimens. Our data-driven approach provides an unbiased means for systematic identification of personalized combinatorial regimens that selectively co-inhibit leukemic cells while avoiding inhibition of non-malignant cells, and highlight the relevance of considering cell heterogeneity for personalized cancer therapy.

Study EGAS00001004614

Systems Analysis of the PfSPZ Vaccine in Kenyan Infants

The PfSPZ vaccine is a candidate vaccine targeting the Plasmodium falciparum parasite, which is the cause of the most lethal type of human malaria. This study used de-identified blood samples collected from 316 infants aged 5 to 12 months (inclusive) enrolled in a Phase 2, randomized, placebo-controlled trial (NCT02687373) of the PfSPZ malaria vaccine, conducted in a region of western Kenya where malaria transmission is high and perennial. The study began in July, 2016, after peak malaria transmission, and was completed in August, 2018. In this study, three doses of the PfSPZ Vaccine (4.5x105 PfSPZ, 9.0x105 PfSPZ, and 1.8x106 PfSPZ) were tested against a normal saline placebo comparator. In all four groups, doses were administered in 3 doses at 0, 8, and 16 weeks by direct venous inoculation. Vaccine efficacy was determined at 3, 6, and 12 months of follow-up after the third immunization. RNA was extracted from whole blood collected in PAXgene tubes before PfSPZ immunization, and two weeks after the third (final) dose, from 262 children for which sufficient material was available at both time points (82% of 316 enrolled children; 525 samples). RNA was depleted of globin and ribosome transcripts before library generation and sequencing on the Illumina NovaSeq platform. RNA-seq expression data was analyzed to determine blood transcriptional signatures, before and after PfSPZ vaccine immunization, that predicts sterile protection from naturally occurring P. falciparum infection or delayed parasitemia at 3 months post-immunization. Gene expression data will also be correlated to P. falciparum-specific IgG antibody and cellular responses to identify possible molecular correlates of vaccine-induced immunogenicity

Study phs002196

Biallelic variants in the non-protein coding minor spliceosome components RNU6ATAC and RNU6ATAC cause syndromic monogenic autoimmune diabetes

Non-protein coding genes are emerging as critical contributors to the aetiology of rare diseases, providing key insights into human biology and uncovering novel disease mechanisms. We identified 7 individuals from 4 families with early-onset diabetes (diagnosed <5 years) and immune dysregulatory features caused by biallelic variants in RNU6ATAC. RNU6ATAC encodes a small nuclear RNA (snRNA) acting as a catalytic component of the minor spliceosome, a protein-RNA complex mediating splicing of ~700 genes containing U12/minor-type introns. Variant screening of the other 64 minor spliceosome genes in 276 infants with diabetes identified 12 unrelated individuals with biallelic disease-causing variants in RNU4ATAC. Biallelic pathogenic RNU4ATAC variants are known to cause a variable spectrum of clinical features, which until now did not include diabetes. Clinically, 12/19 RNU6ATAC/RNU4ATAC patients had additional immune dysregulatory features, and 50% of patients tested were islet-autoantibody positive, strongly supporting an autoimmune aetiology for their diabetes. RNA-seq in 3 individuals with biallelic RNU6ATAC variants showed a pattern of intron retention in U12 intron-containing genes similar to that seen in RNU4ATAC-individuals (n=3), supporting a shared disease mechanism. Analysis of patients’ transcriptomic, methylation and immune data revealed impaired B cell development and maturation. We conclude that biallelic RNU6ATAC variants cause a novel syndrome of early-onset autoimmune diabetes and immune dysregulation. We further show that infancy-onset diabetes is a previously unrecognised feature of RNU4ATACopathy. Our work highlights the important role of two snRNAs critical to minor spliceosome function in immune system regulation, providing novel insights into the pathogenesis of autoimmune diabetes.

Study EGAS50000001565

Single cell RNA sequencing of colorectal cancer patients (CRC-SG1)

Fresh single-cell suspensions were loaded into the Chromium system (10x Genomics) targeting 5,000 cells per well. Barcoded sequencing libraries were generated using 3’v3 Reagent kit.

Study EGAS00001006013

Direct Detection of Early-stage Cancers Using Circulating Tumor DNA

Early detection and intervention are likely to be the most effective means for reducing morbidity and mortality of human cancer. However, development of methods for noninvasive detection of early-stage tumors has remained a challenge. We have developed an approach called targeted error correction sequencing (TEC-Seq) that allows ultrasensitive direct evaluation of sequence changes in circulating cell-free DNA using massively parallel sequencing. We have used this approach to examine 58 cancer-related genes encompassing 81 kb. Analysis of plasma from 44 healthy individuals identified genomic changes related to clonal hematopoiesis in 16% of asymptomatic individuals but no alterations in driver genes related to solid cancers. Evaluation of 200 patients with colorectal, breast, lung, or ovarian cancer detected somatic mutations in the plasma of 71, 59, 59, and 68%, respectively, of patients with stage I or II disease. Analyses of mutations in the circulation revealed high concordance with alterations in the tumors of these patients. In patients with resectable colorectal cancers, higher amounts of preoperative circulating tumor DNA were associated with disease recurrence and decreased overall survival. These analyses provide a broadly applicable approach for noninvasive detection of early-stage tumors that may be useful for screening and management of patients with cancer.

Study EGAS00001002577

Epigenetic Control of Topoisomerase 1 by MacroH2A1.1

DNA transactions introduce torsional constraints that pose an inherent risk to genome integrity. While topoisomerase 1 (TOP1) activity is essential for removing DNA supercoiling, aberrant stabilization of TOP1:DNA cleavage complexes (TOP1ccs) can result in cytotoxic single-stranded DNA lesions (SSLs). What protects the genome from aberrant TOP1 activity remains unknown. Using a combination of CUT&RUN and TOP1 Covalent Adduct Detection (CAD) Seq in MDA-MB-231 breast cancer cells (American Type Culture Collection, ATCC), we identified chromatin context as an essential means to ensure TOP1cc resolution at TOP1 hot spots. Through its ability to bind poly(ADP-ribose) (PAR), a protein modification required for TOP1cc repair, the histone variant macroH2A1.1 establishes a TOP1-permissive chromatin environment, while the alternatively spliced macroH2A1.2 isoform is unable to bind PAR or protect from TOP1ccs. MacroH2A1 isoform-specific analyses were based on reconstitution of macroH2A1.1 knockout cells with wild-type or PAR binding-deficient FLAG-tagged macroH2A1.1 in human breast cancer cells. Mechanistically, we find that macroH2A1.1 facilitates the recruitment of the TOP1cc repair factor XRCC1 in response to both endogenous and drug-induced topological stress. Impaired macroH2A1.1 splicing, a frequent cancer feature, was predictive of increased sensitivity to TOP1 poisons in a pharmaco-genomic screen in breast cancer cells, and macroH2A1.1 inactivation mirrored this effect in breast and ovarian cancer cells. Consistent with this, low macroH2A1.1 expression correlated with improved survival in cancer patients treated with TOP1 inhibitors (TOP1i). We propose that macroH2A1 alternative splicing serves as an epigenetic modulator of TOP1-associated genome maintenance and a potential cancer vulnerability.

Study phs003729

12068 results for "cancer rna-seq"

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