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1.
EMBO Rep ; 25(6): 2662-2697, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38744970

RESUMO

The multifunctional RNA-binding protein hnRNPL is implicated in antibody class switching but its broader function in B cells is unknown. Here, we show that hnRNPL is essential for B cell activation, germinal center formation, and antibody responses. Upon activation, hnRNPL-deficient B cells show proliferation defects and increased apoptosis. Comparative analysis of RNA-seq data from activated B cells and another eight hnRNPL-depleted cell types reveals common effects on MYC and E2F transcriptional programs required for proliferation. Notably, while individual gene expression changes are cell type specific, several alternative splicing events affecting histone modifiers like KDM6A and SIRT1, are conserved across cell types. Moreover, hnRNPL-deficient B cells show global changes in H3K27me3 and H3K9ac. Epigenetic dysregulation after hnRNPL loss could underlie differential gene expression and upregulation of lncRNAs, and explain common and cell type-specific phenotypes, such as dysfunctional mitochondria and ROS overproduction in mouse B cells. Thus, hnRNPL is essential for the resting-to-activated B cell transition by regulating transcriptional programs and metabolism, at least in part through the alternative splicing of several histone modifiers.


Assuntos
Processamento Alternativo , Linfócitos B , Epigênese Genética , Ativação Linfocitária , Animais , Humanos , Camundongos , Apoptose/genética , Linfócitos B/metabolismo , Linfócitos B/imunologia , Proliferação de Células/genética , Regulação da Expressão Gênica , Centro Germinativo/imunologia , Centro Germinativo/metabolismo , Histonas/metabolismo , Ativação Linfocitária/genética
2.
J Immunol ; 207(6): 1599-1615, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34408010

RESUMO

GFI1 is a DNA-binding transcription factor that regulates hematopoiesis by repressing target genes through its association with complexes containing histone demethylases such as KDM1A (LSD1) and histone deacetylases (HDACs). To study the consequences of the disruption of the complex between GFI1 and histone-modifying enzymes, we have used knock-in mice harboring a P2A mutation in GFI1 coding region that renders it unable to bind LSD1 and associated histone-modifying enzymes such as HDACs. GFI1P2A mice die prematurely and show increased numbers of memory effector and regulatory T cells in the spleen accompanied by a severe systemic inflammation with high serum levels of IL-6, TNF-α, and IL-1ß and overexpression of the gene encoding the cytokine oncostatin M (OSM). We identified lung alveolar macrophages, CD8 T cell from the spleen and thymic eosinophils, and monocytes as the sources of these cytokines in GFI1P2A mice. Chromatin immunoprecipitation showed that GFI1/LSD1 complexes occupy sites at the Osm promoter and an intragenic region of the Tnfα gene and that a GFI1P2A mutant still remains bound at these sites even without LSD1. Methylation and acetylation of histone H3 at these sites were enriched in cells from GFI1P2A mice, the H3K27 acetylation being the most significant. These data suggest that the histone modification facilitated by GFI1 is critical to control inflammatory pathways in different cell types, including monocytes and eosinophils, and that a disruption of GFI1-associated complexes can lead to systemic inflammation with fatal consequences.


Assuntos
Proteínas de Ligação a DNA/deficiência , Histona Desmetilases/metabolismo , Proteínas Mutantes/metabolismo , Transdução de Sinais/genética , Síndrome de Resposta Inflamatória Sistêmica/sangue , Fatores de Transcrição/deficiência , Animais , Transplante de Medula Óssea/métodos , Linfócitos T CD8-Positivos/imunologia , Citocinas/sangue , Citocinas/genética , Proteínas de Ligação a DNA/genética , Feminino , Expressão Gênica , Técnicas de Introdução de Genes , Histonas/metabolismo , Macrófagos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , Ligação Proteica , Síndrome de Resposta Inflamatória Sistêmica/genética , Síndrome de Resposta Inflamatória Sistêmica/imunologia , Fatores de Transcrição/genética
3.
Curr Opin Hematol ; 24(1): 32-37, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27820734

RESUMO

PURPOSE OF REVIEW: Growth factor independent 1 (Gfi1) is a transcriptional repressor that plays multiple roles during myeloid commitment and development. Gfi1-deficient mice lack granulocytes, accumulate aberrant monocytes and show a hyperactivity of macrophages toward bacterial cell wall components. Since these initial findings, numerous additional studies have confirmed the role of Gfi1 in myeloid differentiation from hematopoietic stem cells and multipotent progenitors to bipotential lymphoid/myeloid precursors and myeloid effector cells. This review will summarize the existing knowledge concerning the mechanisms through which Gfi1 exerts these actions and will highlight recent insights into its additional implication in myeloid malignancies. RECENT FINDINGS: Gfi1 has more recently been implicated in myeloid malignancies, in particular in myelodysplasia, myeloproliferative neoplasms and in acute myeloid leukemia, a fatal disease, which is essentially treated today the same way as 30 years ago. SUMMARY: Recent findings on the role of Gfi1 in myeloid malignancies together with the knowledge base built over many years on this molecule may help us to find new ways to predict the progression of acute myeloid leukemia and to design more efficient epigenetic drugs to treat this disease.


Assuntos
Diferenciação Celular , Proteínas de Ligação a DNA/metabolismo , Células Mieloides/citologia , Células Mieloides/metabolismo , Fatores de Transcrição/metabolismo , Animais , Diferenciação Celular/genética , Linhagem da Célula/genética , Proteínas de Ligação a DNA/genética , Suscetibilidade a Doenças , Granulócitos/metabolismo , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Humanos , Inflamação/imunologia , Inflamação/metabolismo , Inflamação/patologia , Linfopoese/genética , Mielopoese/genética , Transdução de Sinais , Fatores de Transcrição/genética
4.
PLoS Genet ; 9(9): e1003713, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24068942

RESUMO

Growth factor independent 1 (Gfi1) is a transcriptional repressor originally identified as a gene activated in T-cell leukemias induced by Moloney-murine-leukemia virus infection. Notch1 is a transmembrane receptor that is frequently mutated in human T-cell acute lymphoblastic leukemia (T-ALL). Gfi1 is an important factor in the initiation and maintenance of lymphoid leukemias and its deficiency significantly impedes Notch dependent initiation of T-ALL in animal models. Here, we show that immature hematopoietic cells require Gfi1 to competently integrate Notch-activated signaling. Notch1 activation coupled with Gfi1 deficiency early in T-lineage specification leads to a dramatic loss of T-cells, whereas activation in later stages leaves development unaffected. In Gfi1 deficient multipotent precursors, Notch activation induces lethality and is cell autonomous. Further, without Gfi1, multipotent progenitors do not maintain Notch1-activated global expression profiles typical for T-lineage precursors. In agreement with this, we find that both lymphoid-primed multipotent progenitors (LMPP) and early T lineage progenitors (ETP) do not properly form or function in Gfi1(-/-) mice. These defects correlate with an inability of Gfi1(-/-) progenitors to activate lymphoid genes, including IL7R, Rag1, Flt3 and Notch1. Our data indicate that Gfi1 is required for hematopoietic precursors to withstand Notch1 activation and to maintain Notch1 dependent transcriptional programming to determine early T-lymphoid lineage identity.


Assuntos
Proteínas de Ligação a DNA/genética , Receptor Notch1/genética , Transdução de Sinais/genética , Linfócitos T/citologia , Fatores de Transcrição/genética , Animais , Linhagem da Célula , Regulação Leucêmica da Expressão Gênica/imunologia , Redes Reguladoras de Genes , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Humanos , Linfócitos/citologia , Linfócitos/metabolismo , Camundongos , Linfócitos T/imunologia
5.
Blood ; 118(16): 4394-400, 2011 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-21876120

RESUMO

Immune thrombocytopenia (ITP) is an autoimmune disease with a complex pathogenesis. As in many B cell-related autoimmune diseases, rituximab (RTX) has been shown to increase platelet counts in some ITP patients. From an immunologic standpoint, the mode of action of RTX and the reasons underlying its limited efficacy have yet to be elucidated. Because splenectomy is a cornerstone treatment of ITP, the immune effect of RTX on this major secondary lymphoid organ was investigated in 18 spleens removed from ITP patients who were treated or not with RTX. Spleens from ITP individuals had follicular hyperplasia consistent with secondary follicles. RTX therapy resulted in complete B-cell depletion in the blood and a significant reduction in splenic B cells, but these patients did not achieve remission. Moreover, whereas the percentage of circulating regulatory T cells (Tregs) was similar to that in controls, splenic Tregs were reduced in ITP patients. Interestingly, the ratio of proinflammatory Th1 cells to suppressive Tregs was increased in the spleens of patients who failed RTX therapy. These results indicate that although B cells are involved in ITP pathogenesis, RTX-induced total B-cell depletion is not correlated with its therapeutic effects, which suggests additional immune-mediated mechanisms of action of this drug.


Assuntos
Anticorpos Monoclonais Murinos/imunologia , Fatores Imunológicos/imunologia , Púrpura Trombocitopênica Idiopática/tratamento farmacológico , Baço/efeitos dos fármacos , Adulto , Idoso , Anticorpos Monoclonais Murinos/uso terapêutico , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Feminino , Humanos , Fatores Imunológicos/uso terapêutico , Masculino , Pessoa de Meia-Idade , Púrpura Trombocitopênica Idiopática/imunologia , Rituximab , Baço/citologia , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Células Th1/efeitos dos fármacos , Células Th1/imunologia
6.
Arthritis Rheum ; 64(8): 2499-503, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22488116

RESUMO

OBJECTIVE: From an immunologic standpoint, the mechanisms by which treatment with tocilizumab (TCZ), a humanized anti-interleukin-6 (anti-IL-6) receptor antibody, results in improvement in rheumatoid arthritis (RA) patients are still not fully understood. In vitro studies and studies in mouse models have demonstrated the critical role of IL-6 in Th17 cell differentiation. Th17 lymphocytes have been shown to be strongly involved in RA pathogenesis, and the purpose of this study was to investigate the effect of IL-6 blockade on the balance between Th17 cells and Treg cells in patients with active RA. METHODS: Patients with active RA for whom TCZ had been prescribed by a rheumatologist were enrolled in this study. Phenotypic analyses of T cell populations were performed, and the Disease Activity Score in 28 joints (DAS28) was assessed. Serum cytokine levels and other parameters of inflammation were measured before the first infusion and after the third infusion of TCZ (8 mg/kg). RESULTS: Compared to controls, levels of Th17 cells (CD4+IL-17+) were increased and Treg cells (CD4+CD25(high) FoxP3+) were decreased in the peripheral blood of patients with active RA. The suppressive function of circulating Treg cells was not impaired in patients with active RA. TCZ treatment induced a significant decrease in the DAS28 associated with a significant decrease in the percentage of Th17 cells (from a median of 0.9% to 0.45%; P = 0.009) and an increase in the percentage of Treg cells (from a median of 3.05% to 3.94%; P = 0.0039) in all patients. CONCLUSION: This study demonstrates for the first time that inhibition of IL-6 function by TCZ corrects the imbalance between Th17 cells and Treg cells in patients with RA.


Assuntos
Artrite Reumatoide/patologia , Interleucina-6/antagonistas & inibidores , Linfócitos T Reguladores/patologia , Células Th17/patologia , Adulto , Anticorpos Monoclonais Humanizados/farmacologia , Anticorpos Monoclonais Humanizados/uso terapêutico , Artrite Reumatoide/sangue , Artrite Reumatoide/tratamento farmacológico , Estudos de Casos e Controles , Contagem de Células , Feminino , Humanos , Interleucina-6/sangue , Masculino , Pessoa de Meia-Idade , Fenótipo , Receptores de Interleucina-6/antagonistas & inibidores , Receptores de Interleucina-6/efeitos dos fármacos , Índice de Gravidade de Doença
7.
Arthritis Rheum ; 64(11): 3788-98, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22833233

RESUMO

OBJECTIVE: Giant cell arteritis (GCA) is the most frequently occurring vasculitis in elderly individuals, and its pathogenesis is not fully understood. The objective of this study was to decipher the role of the major CD4+ T cell subsets in GCA and its rheumatologic form, polymyalgia rheumatica (PMR). METHODS: A prospective study of the phenotype and the function of major CD4+ T cell subsets (Th1, Th17, and Treg cells) was performed in 34 untreated patients with GCA or PMR, in comparison with 31 healthy control subjects and with the 27 treated patients who remained after the 7 others withdrew. RESULTS: Compared with control subjects, patients with GCA and patients with PMR had a decreased frequency of Treg cells and Th1 cells, whereas the percentage of Th17 cells was significantly increased. Furthermore, an analysis of temporal artery biopsy specimens obtained from patients affected by GCA for whom biopsy results were positive demonstrated massive infiltration by Th17 and Th1 lymphocytes without any Treg cells. After glucocorticoid treatment, the percentages of circulating Th1 and Th17 cells decreased, whereas no change in the Treg cell frequency was observed. The frequency of CD161+CD4+ T cells, which are considered to be Th17 cell precursors, was similar in patients and control subjects. However, these cells highly infiltrated GCA temporal artery biopsy specimens, and their ability to produce interleukin-17 in vitro was significantly enhanced in patients with GCA and patients with PMR and was correlated with a decrease in the phosphorylated form of STAT-1. CONCLUSION: This study is the first to demonstrate that the frequency of Treg cells is decreased in patients with GCA and patients with PMR, and that CD161+CD4+ T lymphocytes, differentiated into Th1 cells and Th17 cells, are involved in the pathogenesis of GCA and PMR.


Assuntos
Arterite de Células Gigantes/imunologia , Subfamília B de Receptores Semelhantes a Lectina de Células NK/imunologia , Polimialgia Reumática/imunologia , Células Th1/imunologia , Células Th17/imunologia , Adulto , Idoso , Diferenciação Celular/imunologia , Células Cultivadas , Feminino , Citometria de Fluxo , Arterite de Células Gigantes/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Polimialgia Reumática/patologia , Estudos Prospectivos , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/imunologia , Células Th1/citologia , Células Th17/citologia
8.
J Immunol ; 187(5): 2775-82, 2011 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-21804019

RESUMO

Known for years as professional APCs, dendritic cells (DCs) are also endowed with tumoricidal activity. This dual role of DC as killers and messengers may have important implications for tumor immunotherapy. However, the tumoricidal activity of DCs has mainly been investigated in animal models. Cancer cells inhibit antitumor immune responses using numerous mechanisms, including the induction of immunosuppressive/ tolerogenic DCs that have lost their ability to present Ags in an immunogenic manner. In this study, we evaluated the possibility of generating tumor killer DCs from patients with advanced-stage cancers. We demonstrate that human monocyte-derived DCs are endowed with significant cytotoxic activity against tumor cells following activation with LPS. The mechanism of DC-mediated tumor cell killing primarily involves peroxynitrites. This observed cytotoxic activity is restricted to immature DCs. Additionally, after killing, these cytotoxic DCs are able to activate tumor Ag-specific T cells. These observations may open important new perspectives for the use of autologous cytotoxic DCs in cancer immunotherapy strategies.


Assuntos
Citotoxicidade Imunológica/imunologia , Células Dendríticas/imunologia , Imunoterapia/métodos , Neoplasias/imunologia , Células Dendríticas/metabolismo , Citometria de Fluxo , Humanos , Lipopolissacarídeos/imunologia , Lipopolissacarídeos/farmacologia , Ativação Linfocitária/imunologia , Neoplasias/terapia , Ácido Peroxinitroso/imunologia , Ácido Peroxinitroso/metabolismo , Linfócitos T/imunologia
9.
J Immunol ; 184(4): 1876-84, 2010 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-20089706

RESUMO

Dendritic cells (DCs), essential for the initiation and regulation of adaptive immune responses, have been used as anticancer vaccines. DCs may also directly trigger tumor cell death. In the current study, we have investigated the tumoricidal and immunostimulatory activities of mouse bone marrow-derived DCs. Our results indicate that these cells acquire killing capabilities toward tumor cells only when activated with LPS or Pam3Cys-SK4. Using different transgenic mouse models including inducible NO synthase or GP91 knockout mice, we have further established that LPS- or Pam3Cys-SK4-activated DC killing activity involves peroxynitrites. Importantly, after killing of cancer cells, DCs are capable of engulfing dead tumor cell fragments and of presenting tumor Ags to specific T lymphocytes. Thus, upon specific stimulation, mouse bone marrow-derived DCs can directly kill tumor cells through a novel peroxynitrite-dependent mechanism and participate at virtually all levels of antitumor immune responses, which reinforces their interest in immunotherapy.


Assuntos
Apresentação de Antígeno/imunologia , Antígenos de Neoplasias/imunologia , Antígenos de Neoplasias/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Neoplasias Experimentais/imunologia , Neoplasias Experimentais/patologia , Ácido Peroxinitroso/toxicidade , Animais , Morte Celular/imunologia , Linhagem Celular Tumoral , Técnicas de Cocultura , Células HeLa , Humanos , Melanoma Experimental , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Neoplasias Experimentais/metabolismo
10.
Cancer Res ; 82(17): 3172-3186, 2022 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-35815807

RESUMO

The X-linked gene DDX3X encodes an RNA helicase that is mutated at high frequencies in several types of human B-cell lymphoma. Females have two active DDX3X alleles and males carry a DDX3Y homolog on the Y chromosome. We show here that pan-hematopoietic, homozygous deletion of Ddx3x in female mice perturbs erythropoiesis, causing early developmental arrest. However, both hemizygous male and heterozygous female embryos develop normally, suggesting that one Ddx3x allele is sufficient for fetal hematopoietic development in females and that the Ddx3y allele can compensate for the loss of Ddx3x in males. In adult mice, DDX3X deficiency altered hematopoietic progenitors, early lymphoid development, marginal zone and germinal center B cells, and lymphomagenesis in a sex-dependent manner. Loss of both Ddx3x alleles abrogated MYC-driven lymphomagenesis in females, whereas Ddx3x deletion in males did not affect the formation of B-cell lymphoma in both mouse models. Moreover, tumors that appeared in male mice lacking DDX3X showed upregulated expression of DDX3Y, indicating a critical requirement for DDX3 activity for lymphomagenesis. These data reveal sex-specific roles of DDX3X in erythro- and lymphopoiesis as well as in MYC-driven lymphomagenesis. SIGNIFICANCE: The sex-dependent effects of DDX3X deficiency in malignant transformation of B cells and the compensatory role of DDX3Y support inhibition of DDX3 as a treatment strategy for MYC-driven B-cell lymphoma.


Assuntos
RNA Helicases DEAD-box , Genes Ligados ao Cromossomo X , Linfoma de Células B , Animais , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Feminino , Homozigoto , Humanos , Linfoma de Células B/genética , Masculino , Camundongos , Antígenos de Histocompatibilidade Menor , Deleção de Sequência
11.
Cytotherapy ; 13(7): 774-85, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21299362

RESUMO

Dendritic cells (DC) are professional antigen-presenting cells currently being used as a cellular adjuvant in cancer immunotherapy strategies. Unfortunately, DC-based vaccines have not demonstrated spectacular clinical results. DC loading with tumor antigens and DC differentiation and activation still require optimization. An alternative technique for providing antigens to DC consists of the direct fusion of dendritic cells with tumor cells. These resulting hybrid cells may express both major histocompatibility complex (MHC) class I and II molecules associated with tumor antigens and the appropriate co-stimulatory molecules required for T-cell activation. Initially tested in animal models, this approach has now been evaluated in clinical trials, although with limited success. We summarize and discuss the results from the animal studies and first clinical trials. We also present a new approach to inducing hybrid formation by expression of viral fusogenic membrane glycoproteins.


Assuntos
Células Dendríticas/imunologia , Imunoterapia/métodos , Neoplasias/terapia , Animais , Células Apresentadoras de Antígenos/imunologia , Antígenos de Neoplasias/imunologia , Modelos Animais de Doenças , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Células Híbridas , Imunoterapia/tendências , Glicoproteínas de Membrana/imunologia , Glicoproteínas de Membrana/metabolismo
12.
Adv Immunol ; 149: 35-94, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33993920

RESUMO

GFI1 and GFI1B are small nuclear proteins of 45 and 37kDa, respectively, that have a simple two-domain structure: The first consists of a group of six c-terminal C2H2 zinc finger motifs that are almost identical in sequence and bind to very similar, specific DNA sites. The second is an N-terminal 20 amino acid SNAG domain that can bind to the pocket of the histone demethylase KDM1A (LSD1) near its active site. When bound to DNA, both proteins act as bridging factors that bring LSD1 and associated proteins into the vicinity of methylated substrates, in particular histone H3 or TP53. GFI1 can also bring methyl transferases such as PRMT1 together with its substrates that include the DNA repair proteins MRE11 and 53BP1, thereby enabling their methylation and activation. While GFI1B is expressed almost exclusively in the erythroid and megakaryocytic lineage, GFI1 has clear biological roles in the development and differentiation of lymphoid and myeloid immune cells. GFI1 is required for lymphoid/myeloid and monocyte/granulocyte lineage decision as well as the correct nuclear interpretation of a number of important immune-signaling pathways that are initiated by NOTCH1, interleukins such as IL2, IL4, IL5 or IL7, by the pre TCR or -BCR receptors during early lymphoid differentiation or by T and B cell receptors during activation of lymphoid cells. Myeloid cells also depend on GFI1 at both stages of early differentiation as well as later stages in the process of activation of macrophages through Toll-like receptors in response to pathogen-associated molecular patterns. The knowledge gathered on these factors over the last decades puts GFI1 and GFI1B at the center of many biological processes that are critical for both the innate and acquired immune system.


Assuntos
Proteínas de Ligação a DNA , Fatores de Transcrição , Diferenciação Celular , Proteínas de Ligação a DNA/genética , Histona Desmetilases , Humanos , Imunidade , Proteína-Arginina N-Metiltransferases , Proteínas Proto-Oncogênicas/genética , Proteínas Repressoras
13.
Commun Biol ; 4(1): 1356, 2021 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-34857890

RESUMO

Growth factor indepdendent 1 (GFI1) is a SNAG-domain, DNA binding transcriptional repressor which controls myeloid differentiation through molecular mechanisms and co-factors that still remain to be clearly identified. Here we show that GFI1 associates with the chromodomain helicase DNA binding protein 4 (CHD4) and other components of the Nucleosome remodeling and deacetylase (NuRD) complex. In granulo-monocytic precursors, GFI1, CHD4 or GFI1/CHD4 complexes occupy sites enriched for histone marks associated with active transcription suggesting that GFI1 recruits the NuRD complex to target genes regulated by active or bivalent promoters and enhancers. GFI1 and GFI1/CHD4 complexes occupy promoters that are either enriched for IRF1 or SPI1 consensus binding sites, respectively. During neutrophil differentiation, chromatin closure and depletion of H3K4me2 occurs at different degrees depending on whether GFI1, CHD4 or both are present, indicating that GFI1 is more efficient in depleting of H3K4me2 and -me1 marks when associated with CHD4. Our data suggest that GFI1/CHD4 complexes regulate histone modifications differentially to enable regulation of target genes affecting immune response, nucleosome organization or cellular metabolic processes and that both the target gene specificity and the activity of GFI1 during myeloid differentiation depends on the presence of chromatin remodeling complexes.


Assuntos
Cromatina/metabolismo , Proteínas de Ligação a DNA/genética , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase/genética , Células Progenitoras Mieloides/metabolismo , Fatores de Transcrição/genética , Transcrição Gênica , Animais , Proteínas de Ligação a DNA/metabolismo , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase/metabolismo , Camundongos , Fatores de Transcrição/metabolismo
14.
Cancer Immunol Immunother ; 59(1): 1-11, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19618185

RESUMO

Known for years as the principal messengers of the immune system, dendritic cells (DC) represent a heterogeneous population of antigen presenting cells critically located at the nexus between innate and adaptive immunity. DC play a central role in the initiation of tumor-specific immune responses as they are endowed with the unique ability to take up, process and present tumor antigens to naïve CD4(+) or CD8(+) effector T lymphocytes. By virtue of the cytokines they produce, DC also regulate the type, strength and duration of T cell immune responses. In addition, they can participate in anti-tumoral NK and NKT cell activation and in the orchestration of humoral immunity. More recent studies have documented that besides their primary role in the induction and regulation of adaptive anti-tumoral immune responses, DC are also endowed with the capacity to directly kill cancer cells. This dual role of DC as killers and messengers may have important implications for tumor immunotherapy. First, the direct killing of malignant cells by DC may foster the release and thereby the immediate availability of specific tumor antigens for presentation to cytotoxic or helper T lymphocytes. Second, DC may participate in the effector phase of the immune response, potentially augmenting the diversity of the killing mechanisms leading to tumor elimination. This review focuses on this non-conventional cytotoxic function of DC as it relates to the promotion of cancer immunity and discusses the potential application of killer DC (KDC) in tumor immunotherapy.


Assuntos
Citotoxicidade Imunológica , Células Dendríticas/imunologia , Imunoterapia , Células Matadoras Naturais/imunologia , Neoplasias/terapia , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Humanos , Neoplasias/imunologia
15.
Sci Rep ; 9(1): 6304, 2019 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-31004086

RESUMO

Here we demonstrate a mode of reciprocal regulation between GFI1 and p53 that controls the induction of apoptosis in T cells. We show that GFI1 prevents induction of p53 dependent apoptosis by recruiting LSD1 to p53, which leads to the demethylation of its C-terminal domain. This is accompanied by a decrease of the acetylation of lysine 117 within the core domain of the murine p53 protein, which is required for transcriptional induction of apoptosis. Our results support a model in which the effect of GFI1's regulation of methylation at the c-terminus of p53 is ultimately mediated through control of acetylation at lysine 117 of p53. We propose that GFI1 acts prior to the occurrence of DNA damage to affect the post-translational modification state and limit the subsequent activation of p53. Once activated, p53 then transcriptionally activates GFI1, presumably in order to re-establish the homeostatic balance of p53 activity. These findings have implications for the activity level of p53 in various disease contexts where levels of GFI1 are either increased or decreased.


Assuntos
Apoptose , Proteínas de Ligação a DNA/metabolismo , Transdução de Sinais , Linfócitos T/metabolismo , Fatores de Transcrição/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Proteínas de Ligação a DNA/genética , Camundongos , Camundongos Knockout , Linfócitos T/citologia , Fatores de Transcrição/genética , Proteína Supressora de Tumor p53/genética
16.
Leukemia ; 33(1): 110-121, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-29925903

RESUMO

Growth factor independent 1 (Gfi1) controls myeloid differentiation by regulating gene expression and limits the activation of p53 by facilitating its de-methylation at Lysine 372. In human myeloid leukemia, low GFI1 levels correlate with an inferior prognosis. Here, we show that knockdown (KD) of Gfi1 in mice causes a fatal myeloproliferative disease (MPN) that could progress to leukemia after additional mutations. Both KO and KD mice accumulate myeloid cells that show signs of metabolic stress and high levels of reactive oxygen species. However, only KO cells have elevated levels of Lysine 372 methylated p53. This suggests that in contrast to absence of GFI1, KD of GFI1 leads to the accumulation of myeloid cells because sufficient amount of GFI1 is present to impede p53-mediated cell death, leading to a fatal MPN. The combination of myeloid accumulation and the ability to counteract p53 activity under metabolic stress could explain the role of reduced GF1 expression in human myeloid leukemia.


Assuntos
Diferenciação Celular , Proteínas de Ligação a DNA/fisiologia , Leucemia Mieloide/patologia , Células Mieloides/patologia , Transtornos Mieloproliferativos/patologia , Fatores de Transcrição/fisiologia , Animais , Leucemia Mieloide/etiologia , Leucemia Mieloide/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células Mieloides/metabolismo , Transtornos Mieloproliferativos/etiologia , Transtornos Mieloproliferativos/metabolismo , Estresse Oxidativo , Canais de Cátion TRPC/fisiologia
17.
Cancer Res ; 79(16): 4184-4195, 2019 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-31273062

RESUMO

Acute lymphoblastic leukemia (ALL) is an aggressive blood cancer that mainly affects children. Relapse rates are high and toxic chemotherapies that block DNA replication and induce DNA damage lead to health problems later in life, underlining the need for improved therapies. MYC is a transcription factor that is hyperactive in a large proportion of cancers including leukemia but is difficult to target in therapy. We show that ablation of the function of the BTB/POZ domain factor Zbtb17 (Miz-1), an important cofactor of c-Myc, significantly delayed T- and B-ALL/lymphoma in mice and interfered with the oncogenic transcriptional activity of c-Myc. Leukemic cells that still emerged in this system activated DNA replication pathways that could be targeted by current chemotherapeutic drugs such as cytarabine. Acute ablation of the Miz-1 POZ domain enhanced the effect of cytarabine treatment. The combined treatment was effective in both Eµ-Myc and Notch ICN-driven leukemia models and prolonged survival of tumor-bearing animals by accelerating apoptosis of leukemic cells. These observations suggest that targeting MIZ-1 could render current ALL chemotherapies more effective, with a better outcome for patients. SIGNIFICANCE: Ablation of the POZ domain of Miz-1 perturbs its interaction with c-MYC and delays the generation of T- and B-cell leukemias and lymphomas.


Assuntos
Citarabina/farmacologia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Proteínas Inibidoras de STAT Ativados/genética , Ubiquitina-Proteína Ligases/genética , Animais , Antimetabólitos Antineoplásicos/farmacologia , Feminino , Regulação Neoplásica da Expressão Gênica , Genes myc , Camundongos Transgênicos , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Domínios Proteicos , Proteínas Inibidoras de STAT Ativados/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
18.
Nat Commun ; 9(1): 1418, 2018 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-29651020

RESUMO

GFI1 is a transcriptional regulator expressed in lymphoid cells, and an "oncorequisite" factor required for development and maintenance of T-lymphoid leukemia. GFI1 deletion causes hypersensitivity to ionizing radiation, for which the molecular mechanism remains unknown. Here, we demonstrate that GFI1 is required in T cells for the regulation of key DNA damage signaling and repair proteins. Specifically, GFI1 interacts with the arginine methyltransferase PRMT1 and its substrates MRE11 and 53BP1. We demonstrate that GFI1 enables PRMT1 to bind and methylate MRE11 and 53BP1, which is necessary for their function in the DNA damage response. Thus, our results provide evidence that GFI1 can adopt non-transcriptional roles, mediating the post-translational modification of proteins involved in DNA repair. These findings have direct implications for treatment responses in tumors overexpressing GFI1 and suggest that GFI1's activity may be a therapeutic target in these malignancies.


Assuntos
Linfócitos T CD4-Positivos/efeitos da radiação , Reparo do DNA , Proteínas de Ligação a DNA/metabolismo , Proteína Homóloga a MRE11/metabolismo , Processamento de Proteína Pós-Traducional , Proteína-Arginina N-Metiltransferases/metabolismo , Proteínas Repressoras/metabolismo , Fatores de Transcrição/metabolismo , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo , Animais , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/metabolismo , Linhagem Celular , Dano ao DNA , Proteínas de Ligação a DNA/genética , Raios gama , Humanos , Células Jurkat , Proteína Homóloga a MRE11/genética , Metilação , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteína-Arginina N-Metiltransferases/genética , Proteínas Repressoras/genética , Transdução de Sinais , Fatores de Transcrição/genética , Transcrição Gênica , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/genética
20.
PLoS One ; 11(7): e0160344, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27467586

RESUMO

A regulatory circuit that controls myeloid versus B lymphoid cell fate in hematopoietic progenitors has been proposed, in which a network of the transcription factors Egr1/2, Nab, Gfi1 and PU.1 forms the core element. Here we show that a direct link between Gfi1, the transcription factor E2A and its inhibitor Id1 is a critical element of this regulatory circuit. Our data suggest that a certain threshold of Gfi1 is required to gauge E2A activity by adjusting levels of Id1 in multipotent progenitors, which are the first bipotential myeloid/lymphoid-restricted progeny of hematopoietic stem cells. If Gfi1 levels are high, Id1 is repressed enabling E2A to activate a specific set of B lineage genes by binding to regulatory elements for example the IL7 receptor gene. If Gfi1 levels fall below a threshold, Id1 expression increases and renders E2A unable to function, which prevents hematopoietic progenitors from engaging along the B lymphoid lineage.


Assuntos
Linfócitos B/citologia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteína 1 Inibidora de Diferenciação/metabolismo , Fatores de Transcrição/metabolismo , Animais , Linfócitos B/metabolismo , Diferenciação Celular , Linhagem da Célula , Células Cultivadas , Perfilação da Expressão Gênica , Camundongos , Camundongos Transgênicos
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