Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nat Commun ; 12(1): 4991, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404810

RESUMO

Key mechanisms of fetal hemoglobin (HbF) regulation and switching have been elucidated through studies of human genetic variation, including mutations in the HBG1/2 promoters, deletions in the ß-globin locus, and variation impacting BCL11A. While this has led to substantial insights, there has not been a unified understanding of how these distinct genetically-nominated elements, as well as other key transcription factors such as ZBTB7A, collectively interact to regulate HbF. A key limitation has been the inability to model specific genetic changes in primary isogenic human hematopoietic cells to uncover how each of these act individually and in aggregate. Here, we describe a single-cell genome editing functional assay that enables specific mutations to be recapitulated individually and in combination, providing insights into how multiple mutation-harboring functional elements collectively contribute to HbF expression. In conjunction with quantitative modeling and chromatin capture analyses, we illustrate how these genetic findings enable a comprehensive understanding of how distinct regulatory mechanisms can synergistically modulate HbF expression.


Assuntos
Edição de Genes , Hemoglobinas/genética , Hemoglobinas/metabolismo , Sistemas CRISPR-Cas , Cromatina , Cromossomos , Proteínas de Ligação a DNA/metabolismo , Hemoglobina Fetal/genética , Hemoglobina Fetal/metabolismo , Expressão Gênica , Globinas , Humanos , Mutação , Proteínas Repressoras , Fatores de Transcrição/metabolismo , Globinas beta/genética
3.
Nat Genet ; 52(12): 1333-1345, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33230299

RESUMO

Genome-wide association studies identify genomic variants associated with human traits and diseases. Most trait-associated variants are located within cell-type-specific enhancers, but the molecular mechanisms governing phenotypic variation are less well understood. Here, we show that many enhancer variants associated with red blood cell (RBC) traits map to enhancers that are co-bound by lineage-specific master transcription factors (MTFs) and signaling transcription factors (STFs) responsive to extracellular signals. The majority of enhancer variants reside on STF and not MTF motifs, perturbing DNA binding by various STFs (BMP/TGF-ß-directed SMADs or WNT-induced TCFs) and affecting target gene expression. Analyses of engineered human blood cells and expression quantitative trait loci verify that disrupted STF binding leads to altered gene expression. Our results propose that the majority of the RBC-trait-associated variants that reside on transcription-factor-binding sequences fall in STF target sequences, suggesting that the phenotypic variation of RBC traits could stem from altered responsiveness to extracellular stimuli.


Assuntos
Eritrócitos/fisiologia , Regulação da Expressão Gênica/genética , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Fatores de Transcrição/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Elementos Facilitadores Genéticos/genética , Eritrócitos/citologia , Predisposição Genética para Doença/genética , Estudo de Associação Genômica Ampla , Humanos , Locos de Características Quantitativas/genética , Proteína Smad1/genética , Proteína Smad1/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Genética/genética
4.
Nature ; 586(7831): 769-775, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33057200

RESUMO

Myeloproliferative neoplasms (MPNs) are blood cancers that are characterized by the excessive production of mature myeloid cells and arise from the acquisition of somatic driver mutations in haematopoietic stem cells (HSCs). Epidemiological studies indicate a substantial heritable component of MPNs that is among the highest known for cancers1. However, only a limited number of genetic risk loci have been identified, and the underlying biological mechanisms that lead to the acquisition of MPNs remain unclear. Here, by conducting a large-scale genome-wide association study (3,797 cases and 1,152,977 controls), we identify 17 MPN risk loci (P < 5.0 × 10-8), 7 of which have not been previously reported. We find that there is a shared genetic architecture between MPN risk and several haematopoietic traits from distinct lineages; that there is an enrichment for MPN risk variants within accessible chromatin of HSCs; and that increased MPN risk is associated with longer telomere length in leukocytes and other clonal haematopoietic states-collectively suggesting that MPN risk is associated with the function and self-renewal of HSCs. We use gene mapping to identify modulators of HSC biology linked to MPN risk, and show through targeted variant-to-function assays that CHEK2 and GFI1B have roles in altering the function of HSCs to confer disease risk. Overall, our results reveal a previously unappreciated mechanism for inherited MPN risk through the modulation of HSC function.


Assuntos
Predisposição Genética para Doença/genética , Células-Tronco Hematopoéticas/patologia , Transtornos Mieloproliferativos/genética , Transtornos Mieloproliferativos/patologia , Neoplasias/genética , Neoplasias/patologia , Linhagem da Célula/genética , Autorrenovação Celular , Quinase do Ponto de Checagem 2/genética , Feminino , Humanos , Leucócitos/patologia , Masculino , Proteínas Proto-Oncogênicas/genética , Proteínas Repressoras/genética , Risco , Homeostase do Telômero
5.
Nature ; 586(7831): 763-768, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33057201

RESUMO

Age is the dominant risk factor for most chronic human diseases, but the mechanisms through which ageing confers this risk are largely unknown1. The age-related acquisition of somatic mutations that lead to clonal expansion in regenerating haematopoietic stem cell populations has recently been associated with both haematological cancer2-4 and coronary heart disease5-this phenomenon is termed clonal haematopoiesis of indeterminate potential (CHIP)6. Simultaneous analyses of germline and somatic whole-genome sequences provide the opportunity to identify root causes of CHIP. Here we analyse high-coverage whole-genome sequences from 97,691 participants of diverse ancestries in the National Heart, Lung, and Blood Institute Trans-omics for Precision Medicine (TOPMed) programme, and identify 4,229 individuals with CHIP. We identify associations with blood cell, lipid and inflammatory traits that are specific to different CHIP driver genes. Association of a genome-wide set of germline genetic variants enabled the identification of three genetic loci associated with CHIP status, including one locus at TET2 that was specific to individuals of African ancestry. In silico-informed in vitro evaluation of the TET2 germline locus enabled the identification of a causal variant that disrupts a TET2 distal enhancer, resulting in increased self-renewal of haematopoietic stem cells. Overall, we observe that germline genetic variation shapes haematopoietic stem cell function, leading to CHIP through mechanisms that are specific to clonal haematopoiesis as well as shared mechanisms that lead to somatic mutations across tissues.


Assuntos
Hematopoiese Clonal/genética , Predisposição Genética para Doença , Genoma Humano/genética , Sequenciamento Completo do Genoma , Adulto , África/etnologia , Idoso , Idoso de 80 Anos ou mais , Autorrenovação Celular/genética , Proteínas de Ligação a DNA/genética , Dioxigenases , Feminino , Mutação em Linhagem Germinativa/genética , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Pessoa de Meia-Idade , National Heart, Lung, and Blood Institute (U.S.) , Fenótipo , Medicina de Precisão , Proteínas Proto-Oncogênicas/genética , Proteínas com Motivo Tripartido/genética , Estados Unidos , alfa Carioferinas/genética
6.
Trends Genet ; 36(8): 563-576, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32534791

RESUMO

Genome-wide association studies (GWAS) have identified thousands of genetic variants associated with a range of human diseases and traits. However, understanding the mechanisms by which these genetic variants have an impact on associated diseases and traits, often referred to as the variant-to-function (V2F) problem, remains a significant hurdle. Solving the V2F challenge requires us to identify causative genetic variants, relevant cell types/states, target genes, and mechanisms by which variants can cause diseases or alter phenotypic traits. We discuss emerging functional approaches that are being applied to tackle the V2F problem for blood cell traits, illuminating how human genetic variation can impact on key mechanisms in hematopoiesis, as well as highlighting future prospects for this nascent field.


Assuntos
Predisposição Genética para Doença , Variação Genética , Doenças Hematológicas/genética , Hematopoese , Fenótipo , Locos de Características Quantitativas , Animais , Estudos de Associação Genética , Estudo de Associação Genômica Ampla , Doenças Hematológicas/sangue , Doenças Hematológicas/diagnóstico , Doenças Hematológicas/terapia , Humanos
7.
J Clin Immunol ; 40(4): 554-566, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32303876

RESUMO

Studies of genetic blood disorders have advanced our understanding of the intrinsic regulation of hematopoiesis. However, such genetic studies have only yielded limited insights into how interactions between hematopoietic cells and their microenvironment are regulated. Here, we describe two affected siblings with infantile myelofibrosis and myeloproliferation that share a common de novo mutation in the Rho GTPase CDC42 (Chr1:22417990:C>T, p.R186C) due to paternal germline mosaicism. Functional studies using human cells and flies demonstrate that this CDC42 mutant has altered activity and thereby disrupts interactions between hematopoietic progenitors and key tissue microenvironmental factors. These findings suggest that further investigation of this and other related disorders may provide insights into how hematopoietic cell-microenvironment interactions play a role in human health and can be disrupted in disease. In addition, we suggest that deregulation of CDC42 may underlie more common blood disorders, such as primary myelofibrosis.


Assuntos
Mutação/genética , Mielofibrose Primária/diagnóstico , Proteína cdc42 de Ligação ao GTP/genética , Ciclo Celular , Microambiente Celular , Células HEK293 , Hematopoese/genética , Humanos , Lactente , Recém-Nascido , Mielofibrose Primária/genética , Irmãos , Sequenciamento Completo do Exoma
8.
Cell Rep ; 27(11): 3228-3240.e7, 2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-31189107

RESUMO

Human erythropoiesis serves as a paradigm of physiologic cellular differentiation. This process is also of considerable interest for better understanding anemias and identifying new therapies. Here, we apply deep transcriptomic and accessible chromatin profiling to characterize a faithful ex vivo human erythroid differentiation system from hematopoietic stem and progenitor cells. We reveal stage-specific transcriptional states and chromatin accessibility during various stages of erythropoiesis, including 14,260 differentially expressed genes and 63,659 variably accessible chromatin peaks. Our analysis suggests differentiation stage-predominant roles for specific master regulators, including GATA1 and KLF1. We integrate chromatin profiles with common and rare genetic variants associated with erythroid cell traits and diseases, finding that variants regulating different erythroid phenotypes likely act at variable points during differentiation. In addition, we identify a regulator of terminal erythropoiesis, TMCC2, more broadly illustrating the value of this comprehensive analysis to improve our understanding of erythropoiesis in health and disease.


Assuntos
Montagem e Desmontagem da Cromatina , Eritropoese , Transcriptoma , Idoso , Células Cultivadas , Cromatina/química , Cromatina/metabolismo , Células Precursoras Eritroides/citologia , Células Precursoras Eritroides/metabolismo , Feminino , Fator de Transcrição GATA1/genética , Fator de Transcrição GATA1/metabolismo , Células HEK293 , Humanos , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único
9.
Elife ; 82019 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-31070582

RESUMO

Genome-wide association studies (GWAS) have identified thousands of variants associated with human diseases and traits. However, the majority of GWAS-implicated variants are in non-coding regions of the genome and require in depth follow-up to identify target genes and decipher biological mechanisms. Here, rather than focusing on causal variants, we have undertaken a pooled loss-of-function screen in primary hematopoietic cells to interrogate 389 candidate genes contained in 75 loci associated with red blood cell traits. Using this approach, we identify 77 genes at 38 GWAS loci, with most loci harboring 1-2 candidate genes. Importantly, the hit set was strongly enriched for genes validated through orthogonal genetic approaches. Genes identified by this approach are enriched in specific and relevant biological pathways, allowing regulators of human erythropoiesis and modifiers of blood diseases to be defined. More generally, this functional screen provides a paradigm for gene-centric follow up of GWAS for a variety of human diseases and traits.


Assuntos
Doenças Genéticas Inatas , Predisposição Genética para Doença , Hematopoese/genética , Locos de Características Quantitativas/genética , Eritrócitos/metabolismo , Eritrócitos/patologia , Estudo de Associação Genômica Ampla , Humanos , Polimorfismo de Nucleotídeo Único/genética
10.
Proc Natl Acad Sci U S A ; 114(3): E327-E336, 2017 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-28031487

RESUMO

Genetic variants affecting hematopoiesis can influence commonly measured blood cell traits. To identify factors that affect hematopoiesis, we performed association studies for blood cell traits in the population-based Estonian Biobank using high-coverage whole-genome sequencing (WGS) in 2,284 samples and SNP genotyping in an additional 14,904 samples. Using up to 7,134 samples with available phenotype data, our analyses identified 17 associations across 14 blood cell traits. Integration of WGS-based fine-mapping and complementary epigenomic datasets provided evidence for causal mechanisms at several loci, including at a previously undiscovered basophil count-associated locus near the master hematopoietic transcription factor CEBPA The fine-mapped variant at this basophil count association near CEBPA overlapped an enhancer active in common myeloid progenitors and influenced its activity. In situ perturbation of this enhancer by CRISPR/Cas9 mutagenesis in hematopoietic stem and progenitor cells demonstrated that it is necessary for and specifically regulates CEBPA expression during basophil differentiation. We additionally identified basophil count-associated variation at another more pleiotropic myeloid enhancer near GATA2, highlighting regulatory mechanisms for ordered expression of master hematopoietic regulators during lineage specification. Our study illustrates how population-based genetic studies can provide key insights into poorly understood cell differentiation processes of considerable physiologic relevance.


Assuntos
Proteínas Estimuladoras de Ligação a CCAAT/genética , Hematopoese/genética , Sequência de Bases , Basófilos/citologia , Diferenciação Celular/genética , Linhagem da Célula/genética , Mapeamento Cromossômico , Bases de Dados de Ácidos Nucleicos , Elementos Facilitadores Genéticos , Epigênese Genética , Estônia , Feminino , Fator de Transcrição GATA2/genética , Regulação da Expressão Gênica no Desenvolvimento , Estudo de Associação Genômica Ampla , Humanos , Contagem de Leucócitos , Masculino , Polimorfismo de Nucleotídeo Único , Sequenciamento Completo do Genoma
11.
Cell ; 165(6): 1530-1545, 2016 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-27259154

RESUMO

Genome-wide association studies (GWAS) have successfully identified thousands of associations between common genetic variants and human disease phenotypes, but the majority of these variants are non-coding, often requiring genetic fine-mapping, epigenomic profiling, and individual reporter assays to delineate potential causal variants. We employ a massively parallel reporter assay (MPRA) to simultaneously screen 2,756 variants in strong linkage disequilibrium with 75 sentinel variants associated with red blood cell traits. We show that this assay identifies elements with endogenous erythroid regulatory activity. Across 23 sentinel variants, we conservatively identified 32 MPRA functional variants (MFVs). We used targeted genome editing to demonstrate endogenous enhancer activity across 3 MFVs that predominantly affect the transcription of SMIM1, RBM38, and CD164. Functional follow-up of RBM38 delineates a key role for this gene in the alternative splicing program occurring during terminal erythropoiesis. Finally, we provide evidence for how common GWAS-nominated variants can disrupt cell-type-specific transcriptional regulatory pathways.


Assuntos
Eritrócitos , Técnicas Genéticas , Variação Genética , Processamento Alternativo , Linhagem Celular , Linhagem da Célula/genética , Eritropoese/genética , Biblioteca Gênica , Genes Reporter , Humanos , Sequências Reguladoras de Ácido Nucleico , Transcrição Genética
12.
Br J Haematol ; 173(2): 206-18, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26846448

RESUMO

Red blood cells (RBCs) are generated from haematopoietic stem and progenitor cells (HSPCs) through the step-wise process of differentiation known as erythropoiesis. In this review, we discuss our current understanding of erythropoiesis and highlight recent advances in this field. During embryonic development, erythropoiesis occurs in three distinct waves comprising first, the yolk sac-derived primitive RBCs, followed sequentially by the erythro-myeloid progenitor (EMP) and HSPC-derived definitive RBCs. Recent work has highlighted the complexity and variability that may exist in the hierarchical arrangement of progenitors responsible for erythropoiesis. Using recently defined cell surface markers, it is now possible to enrich for erythroid progenitors and precursors to a much greater extent than has been possible before. While a great deal of knowledge has been gained on erythropoiesis from model organisms, our understanding of this process is currently being refined through human genetic studies. Genes mutated in erythroid disorders can now be identified more rapidly by the use of next-generation sequencing techniques. Genome-wide association studies on erythroid traits in healthy populations have also revealed new modulators of erythropoiesis. All of these recent developments have significant promise not only for increasing our understanding of erythropoiesis, but also for improving our ability to intervene when RBC production is perturbed in disease.


Assuntos
Eritropoese/fisiologia , Animais , Comunicação Celular/fisiologia , Diferenciação Celular/fisiologia , Desenvolvimento Embrionário/fisiologia , Eritropoese/genética , Doenças Hematológicas/fisiopatologia , Células-Tronco Hematopoéticas/fisiologia , Hemoglobinas/fisiologia , Xenoenxertos/fisiologia , Humanos , Camundongos , Modelos Biológicos , Transcrição Genética/fisiologia , Peixe-Zebra
13.
Exp Hematol ; 43(7): 565-77.e1-10, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25907033

RESUMO

The transcription factor GATA2 is highly expressed in hematopoietic stem cells and is downregulated during lineage maturation. Gain of function mutations, loss of function mutations, and overexpression of GATA2 have been reported in acute myeloid leukemia. In previous studies, we and others showed that GATA2 overexpression at high levels, similar to that seen in hematopoietic stem cells, blocked differentiation of hematopoietic stem cells and progenitors. To better understand the effects of GATA2, we designed a Tamoxifen-inducible GATA2-estrogen receptor (ERT) vector. In the absence of Tamoxifen, small amounts of GATA2-ERT were still able to enter the nucleus in mouse bone marrow (BM) cells, providing us with a tool to test the effects of low-level GATA2 overexpression. We observed that this low-level GATA2 overexpression enhanced self-renewal of myeloid progenitors in vitro and resulted in immortalization of BM cells to myeloid cell lines. Continuous GATA2-ERT expression was required for the proliferation of these immortalized lines. Myeloid expansion and a block in T and B lineage differentiation were observed in mice transplanted with GATA2-ERT-expressing BM cells. Myeloid expansion occurred after the granulocyte monocyte progenitor stage, and lymphoid block was distal to the common lymphoid progenitor in transgenic mice. GATA2 appeared to induce growth via downstream activation of Nmyc and Hoxa9. Our results demonstrate that GATA2 overexpression at low level confers self-renewal capacity to myeloid progenitors and is relevant to myeloid leukemia development.


Assuntos
Células da Medula Óssea/patologia , Transformação Celular Neoplásica/genética , Fator de Transcrição GATA2/fisiologia , Regulação Leucêmica da Expressão Gênica , Linfopoese/genética , Células Mieloides/patologia , Mielopoese/genética , Animais , Linfócitos B/patologia , Células da Medula Óssea/metabolismo , Divisão Celular , Núcleo Celular/metabolismo , Células Cultivadas , Ensaio de Unidades Formadoras de Colônias , Fator de Transcrição GATA2/genética , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Genes Sintéticos , Genes myc , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Proteínas de Homeodomínio/genética , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutação , Células Mieloides/metabolismo , Receptores de Estrogênio/genética , Proteínas Recombinantes de Fusão/metabolismo , Linfócitos T/patologia , Tamoxifeno/farmacologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...