RESUMO
Ten-eleven translocation (TET) proteins are iron-dependent and α-ketoglutarate-dependent dioxygenases that sequentially oxidize the methyl group of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC). All three epigenetic modifications are intermediates in DNA demethylation. TET proteins are recruited by transcription factors and by RNA polymerase II to modify 5mC at enhancers and gene bodies, thereby regulating gene expression during development, cell lineage specification, and cell activation. It is not yet clear, however, how the established biochemical activities of TET enzymes in oxidizing 5mC and mediating DNA demethylation relate to the known association of TET deficiency with inflammation, clonal hematopoiesis, and cancer. There are hints that the ability of TET deficiency to promote cell proliferation in a signal-dependent manner may be harnessed for cancer immunotherapy. In this review, we draw upon recent findings in cells of the immune system to illustrate established as well as emerging ideas of how TET proteins influence cellular function.
Assuntos
Desmetilação do DNA , Dioxigenases , Imunoterapia , Inflamação , Neoplasias , Humanos , Neoplasias/terapia , Neoplasias/imunologia , Neoplasias/etiologia , Neoplasias/metabolismo , Animais , Inflamação/metabolismo , Inflamação/imunologia , Imunoterapia/métodos , Dioxigenases/metabolismo , Sistema Imunitário/metabolismo , Sistema Imunitário/imunologia , Epigênese Genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas/genética , Metilação de DNA , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Oxigenases de Função Mista/metabolismo , Oxigenases de Função Mista/genéticaRESUMO
Two microglial TAM receptor tyrosine kinases, Axl and Mer, have been linked to Alzheimer's disease, but their roles in disease have not been tested experimentally. We find that in Alzheimer's disease and its mouse models, induced expression of Axl and Mer in amyloid plaque-associated microglia was coupled to induced plaque decoration by the TAM ligand Gas6 and its co-ligand phosphatidylserine. In the APP/PS1 mouse model of Alzheimer's disease, genetic ablation of Axl and Mer resulted in microglia that were unable to normally detect, respond to, organize or phagocytose amyloid-ß plaques. These major deficits notwithstanding, TAM-deficient APP/PS1 mice developed fewer dense-core plaques than APP/PS1 mice with normal microglia. Our findings reveal that the TAM system is an essential mediator of microglial recognition and engulfment of amyloid plaques and that TAM-driven microglial phagocytosis does not inhibit, but rather promotes, dense-core plaque development.
Assuntos
Doença de Alzheimer/imunologia , Microglia/patologia , Proteínas Proto-Oncogênicas/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , c-Mer Tirosina Quinase/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Animais , Encéfalo/citologia , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Modelos Animais de Doenças , Feminino , Humanos , Microscopia Intravital , Masculino , Camundongos , Camundongos Knockout , Microglia/imunologia , Microscopia Confocal , Microscopia de Fluorescência por Excitação Multifotônica , Fagocitose/imunologia , Presenilina-1/genética , Proteínas Proto-Oncogênicas/genética , RNA-Seq , Receptores Proteína Tirosina Quinases/genética , Análise de Célula Única , c-Mer Tirosina Quinase/genética , Receptor Tirosina Quinase AxlRESUMO
During the germinal center (GC) reaction, B cells undergo extensive redistribution of cohesin complex and three-dimensional reorganization of their genomes. Yet, the significance of cohesin and architectural programming in the humoral immune response is unknown. Herein we report that homozygous deletion of Smc3, encoding the cohesin ATPase subunit, abrogated GC formation, while, in marked contrast, Smc3 haploinsufficiency resulted in GC hyperplasia, skewing of GC polarity and impaired plasma cell (PC) differentiation. Genome-wide chromosomal conformation and transcriptional profiling revealed defects in GC B cell terminal differentiation programs controlled by the lymphoma epigenetic tumor suppressors Tet2 and Kmt2d and failure of Smc3-haploinsufficient GC B cells to switch from B cell- to PC-defining transcription factors. Smc3 haploinsufficiency preferentially impaired the connectivity of enhancer elements controlling various lymphoma tumor suppressor genes, and, accordingly, Smc3 haploinsufficiency accelerated lymphomagenesis in mice with constitutive Bcl6 expression. Collectively, our data indicate a dose-dependent function for cohesin in humoral immunity to facilitate the B cell to PC phenotypic switch while restricting malignant transformation.
Assuntos
Linfócitos B/metabolismo , Proteínas de Ciclo Celular/deficiência , Proteínas de Ciclo Celular/genética , Transformação Celular Neoplásica/genética , Proteoglicanas de Sulfatos de Condroitina/genética , Proteínas Cromossômicas não Histona/deficiência , Proteínas Cromossômicas não Histona/genética , Dosagem de Genes , Centro Germinativo/metabolismo , Imunidade Humoral , Linfoma de Células B/genética , Animais , Linfócitos B/imunologia , Linfócitos B/patologia , Proteínas de Ciclo Celular/metabolismo , Diferenciação Celular , Proliferação de Células , Transformação Celular Neoplásica/imunologia , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Células Cultivadas , Proteoglicanas de Sulfatos de Condroitina/deficiência , Proteoglicanas de Sulfatos de Condroitina/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Dioxigenases , Deleção de Genes , Regulação Neoplásica da Expressão Gênica , Centro Germinativo/imunologia , Centro Germinativo/patologia , Haploinsuficiência , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Linfoma de Células B/imunologia , Linfoma de Células B/metabolismo , Linfoma de Células B/patologia , Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/imunologia , Linfoma Difuso de Grandes Células B/metabolismo , Linfoma Difuso de Grandes Células B/patologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína de Leucina Linfoide-Mieloide/genética , Proteína de Leucina Linfoide-Mieloide/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Transdução de Sinais , CoesinasRESUMO
Non-coding genetic variation is a major driver of phenotypic diversity and allows the investigation of mechanisms that control gene expression. Here, we systematically investigated the effects of >50 million variations from five strains of mice on mRNA, nascent transcription, transcription start sites, and transcription factor binding in resting and activated macrophages. We observed substantial differences associated with distinct molecular pathways. Evaluating genetic variation provided evidence for roles of â¼100 TFs in shaping lineage-determining factor binding. Unexpectedly, a substantial fraction of strain-specific factor binding could not be explained by local mutations. Integration of genomic features with chromatin interaction data provided evidence for hundreds of connected cis-regulatory domains associated with differences in transcription factor binding and gene expression. This system and the >250 datasets establish a substantial new resource for investigation of how genetic variation affects cellular phenotypes.
Assuntos
Variação Genética , Macrófagos/metabolismo , Fatores de Transcrição/metabolismo , Animais , Sítios de Ligação , Células da Medula Óssea/citologia , Proteína beta Intensificadora de Ligação a CCAAT/genética , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Análise por Conglomerados , Elementos Facilitadores Genéticos/genética , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Regiões Promotoras Genéticas , Ligação Proteica , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Transativadores/genética , Transativadores/metabolismo , Fatores de Transcrição/genéticaRESUMO
How transcription affects genome 3D organization is not well understood. We found that during influenza A (IAV) infection, rampant transcription rapidly reorganizes host cell chromatin interactions. These changes occur at the ends of highly transcribed genes, where global inhibition of transcription termination by IAV NS1 protein causes readthrough transcription for hundreds of kilobases. In these readthrough regions, elongating RNA polymerase II disrupts chromatin interactions by inducing cohesin displacement from CTCF sites, leading to locus decompaction. Readthrough transcription into heterochromatin regions switches them from the inert (B) to the permissive (A) chromatin compartment and enables transcription factor binding. Data from non-viral transcription stimuli show that transcription similarly affects cohesin-mediated chromatin contacts within gene bodies. Conversely, inhibition of transcription elongation allows cohesin to accumulate at previously transcribed intragenic CTCF sites and to mediate chromatin looping and compaction. Our data indicate that transcription elongation by RNA polymerase II remodels genome 3D architecture.
Assuntos
Cromatina/metabolismo , Genoma Humano , Virus da Influenza A Subtipo H5N1/metabolismo , Sítios de Ligação , Fator de Ligação a CCCTC/química , Fator de Ligação a CCCTC/metabolismo , Proteínas de Transporte/antagonistas & inibidores , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Cromatina/química , Proteínas Cromossômicas não Histona/metabolismo , Flavonoides/farmacologia , Humanos , Interferon beta/farmacologia , Macrófagos/citologia , Macrófagos/metabolismo , Macrófagos/virologia , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Piperidinas/farmacologia , Ligação Proteica , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Interferência de RNA , RNA Polimerase II/genética , RNA Polimerase II/metabolismo , RNA Interferente Pequeno/metabolismo , Transcrição Gênica/efeitos dos fármacos , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , CoesinasRESUMO
Loss-of-function mutations in TET2 occur frequently in patients with clonal hematopoiesis, myelodysplastic syndrome (MDS), and acute myeloid leukemia (AML) and are associated with a DNA hypermethylation phenotype. To determine the role of TET2 deficiency in leukemia stem cell maintenance, we generated a reversible transgenic RNAi mouse to model restoration of endogenous Tet2 expression. Tet2 restoration reverses aberrant hematopoietic stem and progenitor cell (HSPC) self-renewal in vitro and in vivo. Treatment with vitamin C, a co-factor of Fe2+ and α-KG-dependent dioxygenases, mimics TET2 restoration by enhancing 5-hydroxymethylcytosine formation in Tet2-deficient mouse HSPCs and suppresses human leukemic colony formation and leukemia progression of primary human leukemia PDXs. Vitamin C also drives DNA hypomethylation and expression of a TET2-dependent gene signature in human leukemia cell lines. Furthermore, TET-mediated DNA oxidation induced by vitamin C treatment in leukemia cells enhances their sensitivity to PARP inhibition and could provide a safe and effective combination strategy to selectively target TET deficiency in cancer. PAPERCLIP.
Assuntos
Ácido Ascórbico/farmacologia , Proteínas de Ligação a DNA/metabolismo , Leucemia Mieloide Aguda/tratamento farmacológico , Síndromes Mielodisplásicas/tratamento farmacológico , Proteínas Proto-Oncogênicas/metabolismo , Vitaminas/farmacologia , Animais , Ácido Ascórbico/administração & dosagem , Morte Celular , Linhagem Celular Tumoral , Metilação de DNA , Proteínas de Ligação a DNA/genética , Dioxigenases , Técnicas de Silenciamento de Genes , Humanos , Leucemia Mieloide Aguda/genética , Camundongos , Síndromes Mielodisplásicas/genética , Transplante de Neoplasias , Poli(ADP-Ribose) Polimerase-1/genética , Proteínas Proto-Oncogênicas/genética , Transcrição Gênica , Transplante Heterólogo , Vitaminas/administração & dosagemRESUMO
Inactivation of the transcription factor p53, through either direct mutation or aberrations in one of its many regulatory pathways, is a hallmark of virtually every tumor. In recent years, screening for p53 activators and a better understanding of the molecular mechanisms of oncogenic perturbations of p53 function have opened up a host of novel avenues for therapeutic intervention in cancer: from the structure-guided design of chemical chaperones to restore the function of conformationally unstable p53 cancer mutants, to the development of potent antagonists of the negative regulators MDM2 and MDMX and other modulators of the p53 pathway for the treatment of cancers with wild-type p53. Some of these compounds have now moved from proof-of-concept studies into clinical trials, with prospects for further, personalized anticancer medicines. We trace the structural evolution of the p53 pathway, from germ-line surveillance in simple multicellular organisms to its pluripotential role in humans.
Assuntos
Antineoplásicos Alquilantes/uso terapêutico , Regulação Neoplásica da Expressão Gênica , Terapia de Alvo Molecular , Neoplasias/tratamento farmacológico , Proteína Supressora de Tumor p53/agonistas , Animais , Antineoplásicos Alquilantes/síntese química , Proteínas de Ciclo Celular , Ensaios Clínicos como Assunto , Desenho de Fármacos , Humanos , Simulação de Acoplamento Molecular , Mutação , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/química , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Multimerização Proteica , Estrutura Secundária de Proteína , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/química , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-mdm2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-mdm2/química , Proteínas Proto-Oncogênicas c-mdm2/genética , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Transdução de Sinais , Proteína Supressora de Tumor p53/química , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
Neutrophils are essential first-line defense cells against invading pathogens, yet when inappropriately activated, their strong immune response can cause collateral tissue damage and contributes to immunological diseases. However, whether neutrophils can intrinsically titrate their immune response remains unknown. Here we conditionally deleted the Spi1 gene, which encodes the myeloid transcription factor PU.1, from neutrophils of mice undergoing fungal infection and then performed comprehensive epigenomic profiling. We found that as well as providing the transcriptional prerequisite for eradicating pathogens, the predominant function of PU.1 was to restrain the neutrophil defense by broadly inhibiting the accessibility of enhancers via the recruitment of histone deacetylase 1. Such epigenetic modifications impeded the immunostimulatory AP-1 transcription factor JUNB from entering chromatin and activating its targets. Thus, neutrophils rely on a PU.1-installed inhibitor program to safeguard their epigenome from undergoing uncontrolled activation, protecting the host against an exorbitant innate immune response.
Assuntos
Epigênese Genética/imunologia , Epigenômica/métodos , Neutrófilos/imunologia , Proteínas Proto-Oncogênicas/imunologia , Transativadores/imunologia , Animais , Candida albicans/imunologia , Candida albicans/fisiologia , Candidíase/genética , Candidíase/imunologia , Candidíase/microbiologia , Resistência à Doença/genética , Resistência à Doença/imunologia , Perfilação da Expressão Gênica/métodos , Humanos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Neutrófilos/metabolismo , Neutrófilos/microbiologia , Proteínas Proto-Oncogênicas/deficiência , Proteínas Proto-Oncogênicas/genética , Análise de Sobrevida , Transativadores/deficiência , Transativadores/genética , Transcriptoma/genética , Transcriptoma/imunologiaRESUMO
Deleterious somatic mutations in DNA methyltransferase 3 alpha (DNMT3A) and TET mehtylcytosine dioxygenase 2 (TET2) are associated with clonal expansion of hematopoietic cells and higher risk of cardiovascular disease (CVD). Here, we investigated roles of DNMT3A and TET2 in normal human monocyte-derived macrophages (MDM), in MDM isolated from individuals with DNMT3A or TET2 mutations, and in macrophages isolated from human atherosclerotic plaques. We found that loss of function of DNMT3A or TET2 resulted in a type I interferon response due to impaired mitochondrial DNA integrity and activation of cGAS signaling. DNMT3A and TET2 normally maintained mitochondrial DNA integrity by regulating the expression of transcription factor A mitochondria (TFAM) dependent on their interactions with RBPJ and ZNF143 at regulatory regions of the TFAM gene. These findings suggest that targeting the cGAS-type I IFN pathway may have therapeutic value in reducing risk of CVD in patients with DNMT3A or TET2 mutations.
Assuntos
Doenças Cardiovasculares , DNA Metiltransferase 3A/metabolismo , Proteínas de Ligação a DNA/metabolismo , Dioxigenases/metabolismo , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Proteínas de Ligação a DNA/genética , Dioxigenases/genética , Humanos , Interferons/metabolismo , Macrófagos/metabolismo , Mitocôndrias/genética , Mutação/genética , Nucleotidiltransferases/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Transativadores/metabolismoRESUMO
Primitive neuroectodermal tumors of the central nervous system (CNS-PNETs) are highly aggressive, poorly differentiated embryonal tumors occurring predominantly in young children but also affecting adolescents and adults. Herein, we demonstrate that a significant proportion of institutionally diagnosed CNS-PNETs display molecular profiles indistinguishable from those of various other well-defined CNS tumor entities, facilitating diagnosis and appropriate therapy for patients with these tumors. From the remaining fraction of CNS-PNETs, we identify four new CNS tumor entities, each associated with a recurrent genetic alteration and distinct histopathological and clinical features. These new molecular entities, designated "CNS neuroblastoma with FOXR2 activation (CNS NB-FOXR2)," "CNS Ewing sarcoma family tumor with CIC alteration (CNS EFT-CIC)," "CNS high-grade neuroepithelial tumor with MN1 alteration (CNS HGNET-MN1)," and "CNS high-grade neuroepithelial tumor with BCOR alteration (CNS HGNET-BCOR)," will enable meaningful clinical trials and the development of therapeutic strategies for patients affected by poorly differentiated CNS tumors.
Assuntos
Neoplasias do Sistema Nervoso Central/genética , Neoplasias do Sistema Nervoso Central/patologia , Metilação de DNA , Tumores Neuroectodérmicos/genética , Tumores Neuroectodérmicos/patologia , Sequência de Aminoácidos , Neoplasias do Sistema Nervoso Central/classificação , Neoplasias do Sistema Nervoso Central/diagnóstico , Criança , Fatores de Transcrição Forkhead/genética , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Dados de Sequência Molecular , Tumores Neuroectodérmicos/classificação , Tumores Neuroectodérmicos/diagnóstico , Proteínas Proto-Oncogênicas/química , Proteínas Proto-Oncogênicas/genética , Proteínas Repressoras/química , Proteínas Repressoras/genética , Transdução de Sinais , Transativadores , Proteínas Supressoras de Tumor/genéticaRESUMO
Mammalian DNA methylation is a critical epigenetic mechanism orchestrating gene expression networks in many biological processes. However, investigation of the functions of specific methylation events remains challenging. Here, we demonstrate that fusion of Tet1 or Dnmt3a with a catalytically inactive Cas9 (dCas9) enables targeted DNA methylation editing. Targeting of the dCas9-Tet1 or -Dnmt3a fusion protein to methylated or unmethylated promoter sequences caused activation or silencing, respectively, of an endogenous reporter. Targeted demethylation of the BDNF promoter IV or the MyoD distal enhancer by dCas9-Tet1 induced BDNF expression in post-mitotic neurons or activated MyoD facilitating reprogramming of fibroblasts into myoblasts, respectively. Targeted de novo methylation of a CTCF loop anchor site by dCas9-Dnmt3a blocked CTCF binding and interfered with DNA looping, causing altered gene expression in the neighboring loop. Finally, we show that these tools can edit DNA methylation in mice, demonstrating their wide utility for functional studies of epigenetic regulation.
Assuntos
Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA/genética , Proteínas de Ligação a DNA/metabolismo , Epigênese Genética , Edição de Genes/métodos , Proteínas Proto-Oncogênicas/metabolismo , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Fator Neurotrófico Derivado do Encéfalo/genética , Fator de Ligação a CCCTC , Proteína 9 Associada à CRISPR , Linhagem Celular , Ilhas de CpG , DNA (Citosina-5-)-Metiltransferases/genética , DNA Metiltransferase 3A , Proteínas de Ligação a DNA/genética , Endonucleases/genética , Endonucleases/metabolismo , Elementos Facilitadores Genéticos , Genoma , Camundongos , Proteína MyoD/metabolismo , Neurônios/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Proteínas Proto-Oncogênicas/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Repressoras/metabolismoRESUMO
Despite advances in single-cell multi-omics, a single stem or progenitor cell can only be tested once. We developed clonal multi-omics, in which daughters of a clone act as surrogates of the founder, thereby allowing multiple independent assays per clone. With SIS-seq, clonal siblings in parallel "sister" assays are examined either for gene expression by RNA sequencing (RNA-seq) or for fate in culture. We identified, and then validated using CRISPR, genes that controlled fate bias for different dendritic cell (DC) subtypes. This included Bcor as a suppressor of plasmacytoid DC (pDC) and conventional DC type 2 (cDC2) numbers during Flt3 ligand-mediated emergency DC development. We then developed SIS-skew to examine development of wild-type and Bcor-deficient siblings of the same clone in parallel. We found Bcor restricted clonal expansion, especially for cDC2s, and suppressed clonal fate potential, especially for pDCs. Therefore, SIS-seq and SIS-skew can reveal the molecular and cellular mechanisms governing clonal fate.
Assuntos
Células Dendríticas/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Animais , Diferenciação Celular/genética , Linhagem Celular , Linhagem da Célula/genética , Feminino , Expressão Gênica/genética , Células HEK293 , Humanos , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Células-Tronco/metabolismoRESUMO
The polycomb complex component Bmi1 promotes the maintenance of stem cells in multiple postnatal tissues, partly by negatively regulating the expression of p16Ink4a and p19Arf, tumor suppressors associated with cellular senescence. However, deficiency for p16Ink4a and p19Arf only partially rescues the function of Bmi1-deficient stem cells. We conditionally deleted Bmi1 from adult hematopoietic cells and found that this slowly depleted hematopoietic stem cells (HSCs). Rather than inducing senescence, Bmi1 deficiency increased HSC division. The increased cell division was caused partly by increased Aristaless-related homeobox (ARX) transcription factor expression, which also increased ribosomal RNA expression. However, ARX deficiency did not rescue HSC depletion. Bmi1 deficiency also increased protein synthesis, protein aggregation, and protein ubiquitylation independent of its effects on cell division and p16Ink4a, p19Arf, and ARX expression. Bmi1 thus promotes HSC quiescence by negatively regulating ARX expression and promotes proteostasis by suppressing protein synthesis. This highlights a new connection between the regulation of stem cell maintenance and proteostasis.
Assuntos
Inibidor p16 de Quinase Dependente de Ciclina , Proteostase , Inibidor p16 de Quinase Dependente de Ciclina/genética , Células-Tronco Hematopoéticas , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 1/metabolismo , Agregados Proteicos , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , RNA Ribossômico/metabolismoRESUMO
TET proteins oxidize 5-methylcytosine in DNA to 5-hydroxymethylcytosine and other oxidation products. We found that simultaneous deletion of Tet2 and Tet3 in mouse CD4+CD8+ double-positive thymocytes resulted in dysregulated development and proliferation of invariant natural killer T cells (iNKT cells). Tet2-Tet3 double-knockout (DKO) iNKT cells displayed pronounced skewing toward the NKT17 lineage, with increased DNA methylation and impaired expression of genes encoding the key lineage-specifying factors T-bet and ThPOK. Transfer of purified Tet2-Tet3 DKO iNKT cells into immunocompetent recipient mice resulted in an uncontrolled expansion that was dependent on the nonclassical major histocompatibility complex (MHC) protein CD1d, which presents lipid antigens to iNKT cells. Our data indicate that TET proteins regulate iNKT cell fate by ensuring their proper development and maturation and by suppressing aberrant proliferation mediated by the T cell antigen receptor (TCR).
Assuntos
Diferenciação Celular , Proteínas de Ligação a DNA/metabolismo , Células T Matadoras Naturais/fisiologia , Células Precursoras de Linfócitos T/fisiologia , Proteínas Proto-Oncogênicas/metabolismo , Animais , Antígenos CD1d/genética , Antígenos CD1d/metabolismo , Antígenos CD4/metabolismo , Antígenos CD8/metabolismo , Linhagem da Célula , Proliferação de Células , Células Cultivadas , Metilação de DNA/genética , Proteínas de Ligação a DNA/genética , Dioxigenases , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Proto-Oncogênicas/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
The transcription factor STAT5 has a critical role in B cell acute lymphoblastic leukemia (B-ALL). How STAT5 mediates this effect is unclear. Here we found that activation of STAT5 worked together with defects in signaling components of the precursor to the B cell antigen receptor (pre-BCR), including defects in BLNK, BTK, PKCß, NF-κB1 and IKAROS, to initiate B-ALL. STAT5 antagonized the transcription factors NF-κB and IKAROS by opposing regulation of shared target genes. Super-enhancers showed enrichment for STAT5 binding and were associated with an opposing network of transcription factors, including PAX5, EBF1, PU.1, IRF4 and IKAROS. Patients with a high ratio of active STAT5 to NF-κB or IKAROS had more-aggressive disease. Our studies indicate that an imbalance of two opposing transcriptional programs drives B-ALL and suggest that restoring the balance of these pathways might inhibit B-ALL.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Linfócitos B , Regulação Neoplásica da Expressão Gênica , Fator de Transcrição Ikaros/genética , Receptores de Células Precursoras de Linfócitos B/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Fator de Transcrição STAT5/metabolismo , Tirosina Quinase da Agamaglobulinemia , Animais , Imunoprecipitação da Cromatina , Citometria de Fluxo , Humanos , Fatores Reguladores de Interferon/genética , Camundongos , Reação em Cadeia da Polimerase Multiplex , Subunidade p50 de NF-kappa B/genética , Fator de Transcrição PAX5/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidade , Prognóstico , Proteína Quinase C beta/genética , Proteínas Tirosina Quinases/genética , Proteínas Proto-Oncogênicas/genética , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais , Taxa de Sobrevida , Transativadores/genéticaRESUMO
Hematopoietic stem cells (HSCs) sustain blood formation throughout life and are the functional units of bone marrow transplantation. We show that transient expression of six transcription factors Run1t1, Hlf, Lmo2, Prdm5, Pbx1, and Zfp37 imparts multilineage transplantation potential onto otherwise committed lymphoid and myeloid progenitors and myeloid effector cells. Inclusion of Mycn and Meis1 and use of polycistronic viruses increase reprogramming efficacy. The reprogrammed cells, designated induced-HSCs (iHSCs), possess clonal multilineage differentiation potential, reconstitute stem/progenitor compartments, and are serially transplantable. Single-cell analysis revealed that iHSCs derived under optimal conditions exhibit a gene expression profile that is highly similar to endogenous HSCs. These findings demonstrate that expression of a set of defined factors is sufficient to activate the gene networks governing HSC functional identity in committed blood cells. Our results raise the prospect that blood cell reprogramming may be a strategy for derivation of transplantable stem cells for clinical application.
Assuntos
Reprogramação Celular , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Fatores de Transcrição/metabolismo , Animais , Transplante de Células-Tronco Hematopoéticas , Proteínas de Homeodomínio/genética , Camundongos , Camundongos Endogâmicos C57BL , Proteína Meis1 , Proteína Proto-Oncogênica N-Myc , Proteínas de Neoplasias/genética , Proteínas Proto-Oncogênicas/genética , Análise de Célula Única , TranscriptomaRESUMO
Chromatin-binding proteins are critical regulators of cell state in haematopoiesis1,2. Acute leukaemias driven by rearrangement of the mixed lineage leukaemia 1 gene (KMT2Ar) or mutation of the nucleophosmin gene (NPM1) require the chromatin adapter protein menin, encoded by the MEN1 gene, to sustain aberrant leukaemogenic gene expression programs3-5. In a phase 1 first-in-human clinical trial, the menin inhibitor revumenib, which is designed to disrupt the menin-MLL1 interaction, induced clinical responses in patients with leukaemia with KMT2Ar or mutated NPM1 (ref. 6). Here we identified somatic mutations in MEN1 at the revumenib-menin interface in patients with acquired resistance to menin inhibition. Consistent with the genetic data in patients, inhibitor-menin interface mutations represent a conserved mechanism of therapeutic resistance in xenograft models and in an unbiased base-editor screen. These mutants attenuate drug-target binding by generating structural perturbations that impact small-molecule binding but not the interaction with the natural ligand MLL1, and prevent inhibitor-induced eviction of menin and MLL1 from chromatin. To our knowledge, this study is the first to demonstrate that a chromatin-targeting therapeutic drug exerts sufficient selection pressure in patients to drive the evolution of escape mutants that lead to sustained chromatin occupancy, suggesting a common mechanism of therapeutic resistance.
Assuntos
Resistencia a Medicamentos Antineoplásicos , Leucemia , Mutação , Proteínas Proto-Oncogênicas , Animais , Humanos , Antineoplásicos/química , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Sítios de Ligação/efeitos dos fármacos , Sítios de Ligação/genética , Cromatina/genética , Cromatina/metabolismo , Resistencia a Medicamentos Antineoplásicos/genética , Leucemia/tratamento farmacológico , Leucemia/genética , Leucemia/metabolismo , Ligação Proteica/efeitos dos fármacos , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/química , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismoRESUMO
Active DNA demethylation via ten-eleven translocation (TET) family enzymes is essential for epigenetic reprogramming in cell state transitions. TET enzymes catalyze up to three successive oxidations of 5-methylcytosine (5mC), generating 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), or 5-carboxycytosine (5caC). Although these bases are known to contribute to distinct demethylation pathways, the lack of tools to uncouple these sequential oxidative events has constrained our mechanistic understanding of the role of TETs in chromatin reprogramming. Here, we describe the first application of biochemically engineered TET mutants that unlink 5mC oxidation steps, examining their effects on somatic cell reprogramming. We show that only TET enzymes proficient for oxidation to 5fC/5caC can rescue the reprogramming potential of Tet2-deficient mouse embryonic fibroblasts. This effect correlated with rapid DNA demethylation at reprogramming enhancers and increased chromatin accessibility later in reprogramming. These experiments demonstrate that DNA demethylation through 5fC/5caC has roles distinct from 5hmC in somatic reprogramming to pluripotency.
Assuntos
5-Metilcitosina/metabolismo , Reprogramação Celular , Proteínas de Ligação a DNA/metabolismo , Embrião de Mamíferos/metabolismo , Elementos Facilitadores Genéticos , Epigênese Genética , Fibroblastos/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Animais , Proteínas de Ligação a DNA/genética , Dioxigenases , Embrião de Mamíferos/citologia , Fibroblastos/citologia , Células HEK293 , Humanos , Camundongos , Camundongos Knockout , Mutação , Células NIH 3T3 , Proteínas Proto-Oncogênicas/genéticaRESUMO
Reflecting its pleiotropic functions, Polo-like kinase 1 (PLK1) localizes to various sub-cellular structures during mitosis. At kinetochores, PLK1 contributes to microtubule attachments and mitotic checkpoint signaling. Previous studies identified a wealth of potential PLK1 receptors at kinetochores, as well as requirements for various mitotic kinases, including BUB1, Aurora B, and PLK1 itself. Here, we combine ectopic localization, in vitro reconstitution, and kinetochore localization studies to demonstrate that most and likely all of the PLK1 is recruited through BUB1 in the outer kinetochore and centromeric protein U (CENP-U) in the inner kinetochore. BUB1 and CENP-U share a constellation of sequence motifs consisting of a putative PP2A-docking motif and two neighboring PLK1-docking sites, which, contingent on priming phosphorylation by cyclin-dependent kinase 1 and PLK1 itself, bind PLK1 and promote its dimerization. Our results rationalize previous observations and describe a unifying mechanism for recruitment of PLK1 to human kinetochores.
Assuntos
Proteína Quinase CDC2/metabolismo , Proteínas de Ciclo Celular/metabolismo , Histonas/metabolismo , Cinetocoros/metabolismo , Mitose , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteína Quinase CDC2/genética , Proteínas de Ciclo Celular/genética , Células HeLa , Histonas/genética , Humanos , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas/genética , Quinase 1 Polo-LikeRESUMO
Cell state changes are associated with proteome remodeling to serve newly emergent cell functions. Here, we show that NGN2-driven conversion of human embryonic stem cells to induced neurons (iNeurons) is associated with increased PINK1-independent mitophagic flux that is temporally correlated with metabolic reprogramming to support oxidative phosphorylation. Global multiplex proteomics during neurogenesis revealed large-scale remodeling of functional modules linked with pluripotency, mitochondrial metabolism, and proteostasis. Differentiation-dependent mitophagic flux required BNIP3L and its LC3-interacting region (LIR) motif, and BNIP3L also promoted mitophagy in dopaminergic neurons. Proteomic analysis of ATG12-/- iNeurons revealed accumulation of endoplasmic reticulum, Golgi, and mitochondria during differentiation, indicative of widespread organelle remodeling during neurogenesis. This work reveals broad organelle remodeling of membrane-bound organelles during NGN2-driven neurogenesis via autophagy, identifies BNIP3L's central role in programmed mitophagic flux, and provides a proteomic resource for elucidating how organelle remodeling and autophagy alter the proteome during changes in cell state.