Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 10.711
Filtrar
1.
Hematology ; 26(1): 628-636, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34494505

RESUMO

Over the past 20 years, granulocyte colony-stimulating factor (G-CSF) has driven the attention of researchers as a therapeutic agent for curing patients suffering from neutropenia. Despite the successful use of G-CSF, it currently requires daily injections, which are inconvenient, expensive, and distressing for children. Therefore, an alternative strategy for using G-CSF for treatment is needed. Understanding the G-CSF structure, expression, mechanism of action, and how it induces neutrophils mobilization is crucial to producing promising cancer therapy. The ability of G-CSF to mobilize hematopoietic stem cells from the bone marrow into the blood circulation was consequently exploited and altered the practice of hematopoietic stem cell transplantation. This is the motivation for the current review, which sheds light on the history of G-CSF and then focuses on the mechanism of action upon binding to its receptor (G-CSFR) and how that had led to the stimulation of neutrophils mobilization. The findings of this review show new insight into the mechanism of G-CSF that induces neutrophils mobilization. Thus, Understanding the G-CSF will provide a more effective treatment for all neutropenia patients.


Assuntos
Fator Estimulador de Colônias de Granulócitos/metabolismo , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Mobilização de Células-Tronco Hematopoéticas , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/metabolismo , Neutropenia/metabolismo , Neutrófilos/metabolismo , Fator Estimulador de Colônias de Granulócitos/história , Células-Tronco Hematopoéticas/patologia , História do Século XX , História do Século XXI , Humanos , Neutropenia/patologia , Neutropenia/terapia , Neutrófilos/patologia
2.
J Immunol ; 207(4): 1078-1086, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34341172

RESUMO

Emergency granulopoiesis, also known as demand-adapted granulopoiesis, is defined as the response of an organism to systemic bacterial infections, and it results in neutrophil mobilization from reservoir pools and increased myelopoiesis in the bone marrow. Indirect and direct initiating mechanisms of emergency granulopoiesis have been hypothesized. However, the detailed mechanism of hyperactive myelopoiesis in the bone marrow, which leads to granulocyte left shift, remains unknown. In this study, we report that TLR4 is expressed on granulo-monocytic progenitors, as well as mobilized human peripheral blood CD34+ cells, which account for 0.2% of monocytes in peripheral blood, and ∼ 10% in bone marrow. LPS, a component of Gram-negative bacteria that results in a systemic bacterial infection, induces the differentiation of peripheral blood CD34+ cells into myelocytes and monocytes in vitro via the TLR4 signaling pathway. Moreover, CD34+ cells directly responded to LPS stimulation by activating the MAPK and NF-κB signaling pathways, and they produced IL-6 that promotes emergency granulopoiesis by phosphorylating C/EBPα and C/EBPß, and this effect was suppressed by the action of an IL-6 receptor inhibitor. This work supports the finding that TLR is expressed on human hematopoietic stem and progenitor cells, and it provides evidence that human hematopoietic stem and progenitor cells can directly sense pathogens and produce cytokines exerting autocrine and/or paracrine effects, thereby promoting differentiation.


Assuntos
Granulócitos/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Interleucina-6/metabolismo , Transdução de Sinais/fisiologia , Células-Tronco/metabolismo , Receptor 4 Toll-Like/metabolismo , Adaptação Fisiológica/fisiologia , Antígenos CD34/metabolismo , Medula Óssea/metabolismo , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Diferenciação Celular/fisiologia , Citocinas/metabolismo , Regulação da Expressão Gênica/fisiologia , Células Precursoras de Granulócitos/metabolismo , Transplante de Células-Tronco Hematopoéticas/métodos , Humanos , Monócitos/metabolismo , Mielopoese/fisiologia
3.
Int J Mol Sci ; 22(16)2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34445246

RESUMO

The hematopoietic system relies on regulation of both metabolism and autophagy to maintain its homeostasis, ensuring the self-renewal and multipotent differentiation potential of hematopoietic stem cells (HSCs). HSCs display a distinct metabolic profile from that of their differentiated progeny, while metabolic rewiring from glycolysis to oxidative phosphorylation (OXPHOS) has been shown to be crucial for effective hematopoietic differentiation. Autophagy-mediated regulation of metabolism modulates the distinct characteristics of quiescent and differentiating hematopoietic cells. In particular, mitophagy determines the cellular mitochondrial content, thus modifying the level of OXPHOS at the different differentiation stages of hematopoietic cells, while, at the same time, it ensures the building blocks and energy for differentiation. Aberrations in both the metabolic status and regulation of the autophagic machinery are implicated in the development of hematologic malignancies, especially in leukemogenesis. In this review, we aim to investigate the role of metabolism and autophagy, as well as their interconnections, in normal and malignant hematopoiesis.


Assuntos
Carcinogênese/metabolismo , Neoplasias Hematológicas/metabolismo , Hematopoese , Células-Tronco Hematopoéticas/metabolismo , Leucemia/metabolismo , Mitocôndrias/metabolismo , Mitofagia , Animais , Carcinogênese/patologia , Diferenciação Celular , Neoplasias Hematológicas/patologia , Células-Tronco Hematopoéticas/patologia , Humanos , Leucemia/patologia , Mitocôndrias/patologia
4.
Nat Commun ; 12(1): 4706, 2021 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-34349112

RESUMO

During mammalian pregnancy, immune cells are vertically transferred from mother to fetus. The functional role of these maternal microchimeric cells (MMc) in the offspring is mostly unknown. Here we show a mouse model in which MMc numbers are either normal or low, which enables functional assessment of MMc. We report a functional role of MMc in promoting fetal immune development. MMc induces preferential differentiation of hematopoietic stem cells in fetal bone marrow towards monocytes within the myeloid compartment. Neonatal mice with higher numbers of MMc and monocytes show enhanced resilience against cytomegalovirus infection. Similarly, higher numbers of MMc in human cord blood are linked to a lower number of respiratory infections during the first year of life. Our data highlight the importance of MMc in promoting fetal immune development, potentially averting the threats caused by early life exposure to pathogens.


Assuntos
Quimerismo , Feto/imunologia , Imunidade Materno-Adquirida/imunologia , Infecções/imunologia , Animais , Medula Óssea/metabolismo , Epigenoma , Feminino , Sangue Fetal/citologia , Hematopoese , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Humanos , Lactente , Camundongos , Monócitos/citologia , Gravidez , Linfócitos T/citologia
5.
Nat Commun ; 12(1): 4921, 2021 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-34389724

RESUMO

Age-related clonal hematopoiesis (ARCH) is characterized by age-associated accumulation of somatic mutations in hematopoietic stem cells (HSCs) or their pluripotent descendants. HSCs harboring driver mutations will be positively selected and cells carrying these mutations will rise in frequency. While ARCH is a known risk factor for blood malignancies, such as Acute Myeloid Leukemia (AML), why some people who harbor ARCH driver mutations do not progress to AML remains unclear. Here, we model the interaction of positive and negative selection in deeply sequenced blood samples from individuals who subsequently progressed to AML, compared to healthy controls, using deep learning and population genetics. Our modeling allows us to discriminate amongst evolutionary classes with high accuracy and captures signatures of purifying selection in most individuals. Purifying selection, acting on benign or mildly damaging passenger mutations, appears to play a critical role in preventing disease-predisposing clones from rising to dominance and is associated with longer disease-free survival. Through exploring a range of evolutionary models, we show how different classes of selection shape clonal dynamics and health outcomes thus enabling us to better identify individuals at a high risk of malignancy.


Assuntos
Evolução Clonal , Hematopoiese Clonal/genética , Células-Tronco Hematopoéticas/metabolismo , Leucemia Mieloide/genética , Mutação , Doença Aguda , Adulto , Idoso , Aprendizado Profundo , Genética Populacional/métodos , Genética Populacional/estatística & dados numéricos , Células-Tronco Hematopoéticas/citologia , Humanos , Estimativa de Kaplan-Meier , Leucemia Mieloide/patologia , Pessoa de Meia-Idade , Modelos Genéticos , Avaliação de Resultados em Cuidados de Saúde/métodos , Avaliação de Resultados em Cuidados de Saúde/estatística & dados numéricos
6.
Nat Commun ; 12(1): 4922, 2021 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-34389729

RESUMO

CRISPR-Cas9 is a promising technology for gene therapy. However, the ON-target genotoxicity of CRISPR-Cas9 nuclease due to DNA double-strand breaks has received little attention and is probably underestimated. Here we report that genome editing targeting globin genes induces megabase-scale losses of heterozygosity (LOH) from the globin CRISPR-Cas9 cut-site to the telomere (5.2 Mb). In established lines, CRISPR-Cas9 nuclease induces frequent terminal chromosome 11p truncations and rare copy-neutral LOH. In primary hematopoietic progenitor/stem cells, we detect 1.1% of clones (7/648) with acquired megabase LOH induced by CRISPR-Cas9. In-depth analysis by SNP-array reveals the presence of copy-neutral LOH. This leads to 11p15.5 partial uniparental disomy, comprising two Chr11p15.5 imprinting centers (H19/IGF2:IG-DMR/IC1 and KCNQ1OT1:TSS-DMR/IC2) and impacting H19 and IGF2 expression. While this genotoxicity is a safety concern for CRISPR clinical trials, it is also an opportunity to model copy-neutral-LOH for genetic diseases and cancers.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes/métodos , Globinas/genética , Células-Tronco Hematopoéticas/metabolismo , Perda de Heterozigosidade/genética , Deleção de Sequência , Células Cultivadas , Deleção Cromossômica , Cromossomos Humanos Par 11/genética , Metilação de DNA , Expressão Gênica , Células HEK293 , Células-Tronco Hematopoéticas/citologia , Humanos , Fator de Crescimento Insulin-Like II/genética , Polimorfismo de Nucleotídeo Único , RNA Longo não Codificante/genética
7.
Int J Mol Sci ; 22(13)2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34203224

RESUMO

Previous work pointed to a critical role of excessive production of reactive oxygen species (ROS) in increased radiation hematopoietic death in GFP mice. Meanwhile, enhanced antioxidant capability was not demonstrated in the mouse model of radio-induced adaptive response (RAR) using rescue of radiation hematopoietic death as the endpoint. ROS induction by ex vivo X-irradiation at a dose ranging from 0.1 to 7.5 Gy in the nucleated bone marrow cells was comparatively studied using GFP and wild type (WT) mice. ROS induction was also investigated in the cells collected from mice receiving a priming dose (0.5 Gy) efficient for RAR induction in WT mice. Significantly elevated background and increased induction of ROS in the cells from GFP mice were observed compared to those from WT mice. Markedly lower background and decreased induction of ROS were observed in the cells collected from WT mice but not GFP mice, both receiving the priming dose. GFP overexpression could alter background and induction of ROS by X-irradiation in hematopoietic cells. The results provide a reasonable explanation to the previous study on the fate of cells and mice after X-irradiation and confirm enhanced antioxidant capability in RAR. Investigations involving GFP overexpression should be carefully interpreted.


Assuntos
Células da Medula Óssea/metabolismo , Células da Medula Óssea/efeitos da radiação , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Hematopoéticas/efeitos da radiação , Espécies Reativas de Oxigênio/metabolismo , Raios X/efeitos adversos , Animais , Relação Dose-Resposta à Radiação , Feminino , Camundongos , Camundongos Endogâmicos C57BL
8.
Blood ; 138(3): 221-233, 2021 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-34292326

RESUMO

The Chd8 gene encodes a member of the chromodomain helicase DNA-binding (CHD) family of SNF2H-like adenosine triphosphate (ATP)-dependent chromatin remodeler, the mutations of which define a subtype of autism spectrum disorders. Increasing evidence from recent studies indicates that ATP-dependent chromatin-remodeling genes are involved in the control of crucial gene-expression programs in hematopoietic stem/progenitor cell (HSPC) regulation. In this study, we identified CHD8 as a specific and essential regulator of normal hematopoiesis. Loss of Chd8 leads to severe anemia, pancytopenia, bone marrow failure, and engraftment failure related to a drastic depletion of HSPCs. CHD8 forms a complex with ATM and its deficiency increases chromatin accessibility and drives genomic instability in HSPCs causing an activation of ATM kinase that further stabilizes P53 protein by phosphorylation and leads to increased HSPC apoptosis. Deletion of P53 rescues the apoptotic defects of HSPCs and restores overall hematopoiesis in Chd8-/- mice. Our findings demonstrate that chromatin organization by CHD8 is uniquely necessary for the maintenance of hematopoiesis by integrating the ATM-P53-mediated survival of HSPCs.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Hematopoese , Células-Tronco Hematopoéticas/citologia , Proteína Supressora de Tumor p53/metabolismo , Animais , Apoptose , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Sobrevivência Celular , Células Cultivadas , Proteínas de Ligação a DNA/genética , Deleção de Genes , Células-Tronco Hematopoéticas/metabolismo , Camundongos , Pancitopenia/genética , Pancitopenia/metabolismo , Estabilidade Proteica
9.
Int J Hematol ; 114(3): 363-372, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34213732

RESUMO

Autologous stem cell transplantation (ASCT) is a standard of care in newly-diagnosed multiple myeloma (MM) patients. Several studies before the introduction of novel therapies in MM, demonstrated a pegylated G-CSF to be successful in mobilizing peripheral blood stem cells (PBSCs). Lipegfilgrastim is a novel long-acting G-CSF that is produced by the conjugation of a single 20-kDa polyethelene glycol to the natural O-glycosylation site of G-CSF. Twenty-four MM patients were included for PBSCs mobilization with a single SC injection of 6 mg lipegfilgrastim. PBSC collection was started when the CD34+ count was > 10 × 106 cells/L. The target progenitor cells were 6 × 106 cells/kg. The median day of apheresis was + 3 (range 2-5) following lipegfilgrastim. Median peripheral blood CD34+ count pre-mobilization was of 22.65 (range 3.36-105) × 106 cells/L. The median number of leukaphaeresis procedures was 2 (range 1-4). The median mobilized CD34+ cells/kg were 8.26 (range 0.77-12.42). One patient failed to mobilize and two patients mobilized < 6 × 106 cells/kg. Toxicity was mild and transient. Twenty-three patients underwent ASCT following high dose melphalan. All patients engrafted. As lipegfilgrastim is administered only once, it is conceivable that it improves both compliance and quality-of-life (NCT02488382).


Assuntos
Filgrastim/administração & dosagem , Mobilização de Células-Tronco Hematopoéticas , Transplante de Células-Tronco Hematopoéticas , Mieloma Múltiplo/terapia , Polietilenoglicóis/administração & dosagem , Adulto , Idoso , Remoção de Componentes Sanguíneos , Feminino , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Mobilização de Células-Tronco Hematopoéticas/métodos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Transplante de Células-Tronco Hematopoéticas/métodos , Células-Tronco Hematopoéticas/metabolismo , Humanos , Imunofenotipagem , Masculino , Pessoa de Meia-Idade , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Transplante Autólogo , Resultado do Tratamento
10.
Nat Commun ; 12(1): 4549, 2021 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-34315901

RESUMO

Germline pathogenic variants in DNMT3A were recently described in patients with overgrowth, obesity, behavioral, and learning difficulties (DNMT3A Overgrowth Syndrome/DOS). Somatic mutations in the DNMT3A gene are also the most common cause of clonal hematopoiesis, and can initiate acute myeloid leukemia (AML). Using whole genome bisulfite sequencing, we studied DNA methylation in peripheral blood cells of 11 DOS patients and found a focal, canonical hypomethylation phenotype, which is most severe with the dominant negative DNMT3AR882H mutation. A germline mouse model expressing the homologous Dnmt3aR878H mutation phenocopies most aspects of the human DOS syndrome, including the methylation phenotype and an increased incidence of spontaneous hematopoietic malignancies, suggesting that all aspects of this syndrome are caused by this mutation.


Assuntos
Anormalidades Múltiplas/genética , DNA (Citosina-5-)-Metiltransferases/genética , Epigênese Genética , Anormalidades Múltiplas/sangue , Adolescente , Adulto , Animais , Comportamento Animal , Peso Corporal/genética , Células da Medula Óssea/metabolismo , Criança , Pré-Escolar , Ilhas de CpG/genética , Metilação de DNA/genética , Feminino , Perfilação da Expressão Gênica , Mutação em Linhagem Germinativa/genética , Hematopoese/genética , Células-Tronco Hematopoéticas/metabolismo , Humanos , Lactente , Leucemia/genética , Leucemia/patologia , Masculino , Camundongos Endogâmicos C57BL , Obesidade/genética , Fenótipo , Síndrome , Transcrição Genética
11.
Curr Opin Hematol ; 28(5): 364-371, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34232140

RESUMO

PURPOSE OF REVIEW: Bone marrow fibrosis is the progressive replacement of blood-forming cells by reticulin fibres, caused by the acquisition of somatic mutations in hematopoietic stem cells. The molecular and cellular mechanisms that drive the progression of bone marrow fibrosis remain unknown, yet chronic inflammation appears to be a conserved feature in most patients suffering from myeloproliferative neoplasms. RECENT FINDINGS: Here, we review recent literature pertaining to the role of inflammation in driving bone marrow fibrosis, and its effect on the various hematopoietic and nonhematopoietic cell populations. SUMMARY: Recent evidence suggests that the pathogenesis of MPN is primarily driven by the hematopoietic stem and progenitor cells, together with their mutated progeny, which in turn results in chronic inflammation that disrupts the bone marrow niche and perpetuates a disease-permissive environment. Emerging data suggests that specifically targeting stromal inflammation in combination with JAK inhibition may be the way forward to better treat MPNs, and bone marrow fibrosis specifically.


Assuntos
Medula Óssea , Neoplasias Hematológicas , Células-Tronco Hematopoéticas , Mielofibrose Primária , Medula Óssea/metabolismo , Medula Óssea/patologia , Neoplasias Hematológicas/tratamento farmacológico , Neoplasias Hematológicas/metabolismo , Neoplasias Hematológicas/patologia , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Hematopoéticas/patologia , Humanos , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Inflamação/patologia , Transtornos Mieloproliferativos/tratamento farmacológico , Transtornos Mieloproliferativos/metabolismo , Transtornos Mieloproliferativos/patologia , Mielofibrose Primária/tratamento farmacológico , Mielofibrose Primária/metabolismo , Mielofibrose Primária/patologia
12.
Int J Mol Sci ; 22(14)2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-34299194

RESUMO

A heterogeneous genetic subtype of B-cell precursor acute lymphoblastic leukemia is driven by constitutive kinase-activation, including patients with JAK2 fusions. In our study, we model the impact of a novel JAK2 fusion protein on hematopoietic development in human induced pluripotent stem cells (hiPSCs). We insert the RUNX1-JAK2 fusion into one endogenous RUNX1 allele through employing in trans paired nicking genome editing. Tagging of the fusion with a degron facilitates protein depletion using the heterobifunctional compound dTAG-13. Throughout in vitro hematopoietic differentiation, the expression of RUNX1-JAK2 is driven by endogenous RUNX1 regulatory elements at physiological levels. Functional analysis reveals that RUNX1-JAK2 knock-in cell lines yield fewer hematopoietic progenitors, due to RUNX1 haploinsufficiency. Nevertheless, these progenitors further differentiate toward myeloid lineages to a similar extent as wild-type cells. The expression of the RUNX1-JAK2 fusion protein only elicits subtle effects on myeloid differentiation, and is unable to transform early hematopoietic progenitors. However, phosphoprotein and transcriptome analyses reveal that RUNX1-JAK2 constitutively activates JAK-STAT signaling in differentiating hiPSCs and at the same time upregulates MYC targets-confirming the interaction between these pathways. This proof-of-principle study indicates that conditional expression of oncogenic fusion proteins in combination with hematopoietic differentiation of hiPSCs may be applicable to leukemia-relevant disease modeling.


Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Janus Quinase 2/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Fatores de Transcrição STAT/metabolismo , Diferenciação Celular , Células Cultivadas , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Perfilação da Expressão Gênica/métodos , Células-Tronco Hematopoéticas/citologia , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Janus Quinase 2/genética , Proteínas de Fusão Oncogênica/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Transdução de Sinais
13.
Nat Commun ; 12(1): 4484, 2021 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-34301940

RESUMO

Reactive oxygen species (ROS) represent a by-product of metabolism and their excess is toxic for hematopoietic stem and progenitor cells (HSPCs). During embryogenesis, a small number of HSPCs are produced from the hemogenic endothelium, before they colonize a transient organ where they expand, for example the fetal liver in mammals. In this study, we use zebrafish to understand the molecular mechanisms that are important in the caudal hematopoietic tissue (equivalent to the mammalian fetal liver) to promote HSPC expansion. High levels of ROS are deleterious for HSPCs in this niche, however this is rescued by addition of antioxidants. We show that Cx41.8 is important to lower ROS levels in HSPCs. We also demonstrate a new role for ifi30, known to be involved in the immune response. In the hematopoietic niche, Ifi30 can recycle oxidized glutathione to allow HSPCs to dampen their levels of ROS, a role that could be conserved in human fetal liver.


Assuntos
Conexinas/genética , Células-Tronco Hematopoéticas/metabolismo , Estresse Oxidativo , Oxirredutases atuantes sobre Doadores de Grupo Enxofre/genética , Transdução de Sinais/genética , Nicho de Células-Tronco , Proteínas de Peixe-Zebra/genética , Animais , Animais Geneticamente Modificados , Conexinas/metabolismo , Embrião não Mamífero/citologia , Embrião não Mamífero/embriologia , Embrião não Mamífero/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Células-Tronco Hematopoéticas/citologia , Humanos , Microscopia Confocal , Mutação , Oxirredutases atuantes sobre Doadores de Grupo Enxofre/metabolismo , Imagem com Lapso de Tempo/métodos , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
14.
Rinsho Ketsueki ; 62(5): 521-527, 2021.
Artigo em Japonês | MEDLINE | ID: mdl-34248130

RESUMO

Cell cycle quiescence is a fundamental property of hematopoietic stem cells (HSCs). Quiescent HSCs form a healthy pool of cells that serve as a reserve for massive HSC expansion under various conditions of stress. We previously reported that thrombopoietin (THPO) maintains quiescent HSCs and stimulates mitochondrial metabolism, megakaryocyte-lineage differentiation, and proliferation of HSCs. The underlying mechanism by which THPO balances its contradictory effect of promoting proliferation or quiescence on HSCs remains unknown. This review explores the role of THPO signaling in HSC differentiation and quiescence regulation. We present our data, which suggests that a THPO-independent HSC subpopulation sustaining a low mitochondrial metabolic profile reverts to quiescence and regains stem cell potential with external stimuli. There is a possibility that THPO-independent HSCs form a non-quiescent reserve HSC pool from which quiescent HSCs originate in the adult bone marrow.


Assuntos
Células-Tronco Hematopoéticas , Trombopoetina , Ciclo Celular , Células-Tronco Hematopoéticas/metabolismo , Homeostase , Mitocôndrias , Receptores de Trombopoetina
15.
Nat Commun ; 12(1): 4559, 2021 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-34315896

RESUMO

Activating mutations in the BRAF-MAPK pathway have been reported in histiocytoses, hematological inflammatory neoplasms characterized by multi-organ dissemination of pro-inflammatory myeloid cells. Here, we generate a humanized mouse model of transplantation of human hematopoietic stem and progenitor cells (HSPCs) expressing the activated form of BRAF (BRAFV600E). All mice transplanted with BRAFV600E-expressing HSPCs succumb to bone marrow failure, displaying myeloid-restricted hematopoiesis and multi-organ dissemination of aberrant mononuclear phagocytes. At the basis of this aggressive phenotype, we uncover the engagement of a senescence program, characterized by DNA damage response activation and a senescence-associated secretory phenotype, which affects also non-mutated bystander cells. Mechanistically, we identify TNFα as a key determinant of paracrine senescence and myeloid-restricted hematopoiesis and show that its inhibition dampens inflammation, delays disease onset and rescues hematopoietic defects in bystander cells. Our work establishes that senescence in the human hematopoietic system links oncogene-activation to the systemic inflammation observed in histiocytic neoplasms.


Assuntos
Senescência Celular , Hematopoese/genética , Células-Tronco Hematopoéticas/metabolismo , Histiocitose/patologia , Inflamação/patologia , Células Mieloides/patologia , Oncogenes , Animais , Medula Óssea/patologia , Pontos de Checagem do Ciclo Celular/genética , Senescência Celular/genética , Doença Crônica , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Regulação da Expressão Gênica , Proteínas de Fluorescência Verde/metabolismo , Histiocitose/complicações , Humanos , Inflamação/complicações , Lentivirus/genética , Camundongos , Mutação/genética , Comunicação Parácrina , Análise de Componente Principal , Proteínas Proto-Oncogênicas B-raf/genética , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/metabolismo
16.
Commun Biol ; 4(1): 868, 2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-34262131

RESUMO

Hematopoietic stem/progenitor cell (HSPC) and leukemic cell homing is an important biological phenomenon that occurs through key interactions between adhesion molecules. Tethering and rolling of the cells on endothelium, the crucial initial step of the adhesion cascade, is mediated by interactions between selectins expressed on endothelium to their ligands expressed on HSPCs/leukemic cells in flow. Although multiple factors that affect the rolling behavior of the cells have been identified, molecular mechanisms that enable the essential slow and stable cell rolling remain elusive. Here, using a microfluidics-based single-molecule live cell fluorescence imaging, we reveal that unique spatiotemporal dynamics of selectin ligands on the membrane tethers and slings, which are distinct from that on the cell body, play an essential role in the rolling of the cell. Our results suggest that the spatial confinement of the selectin ligands to the tethers and slings together with the rapid scanning of a large area by the selectin ligands, increases the efficiency of selectin-ligand interactions during cell rolling, resulting in slow and stable rolling of the cell on the selectins. Our findings provide novel insights and contribute significantly to the molecular-level understanding of the initial and essential step of the homing process.


Assuntos
Selectina E/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Leucemia Mieloide Aguda/metabolismo , Microfluídica/métodos , Imagem Individual de Molécula/métodos , Algoritmos , Adesão Celular/fisiologia , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Células Cultivadas , Células-Tronco Hematopoéticas/citologia , Humanos , Leucemia Mieloide Aguda/patologia , Ligantes , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência/métodos , Modelos Biológicos
17.
Nature ; 595(7866): 295-302, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34079130

RESUMO

Sickle cell disease (SCD) is caused by a mutation in the ß-globin gene HBB1. We used a custom adenine base editor (ABE8e-NRCH)2,3 to convert the SCD allele (HBBS) into Makassar ß-globin (HBBG), a non-pathogenic variant4,5. Ex vivo delivery of mRNA encoding the base editor with a targeting guide RNA into haematopoietic stem and progenitor cells (HSPCs) from patients with SCD resulted in 80% conversion of HBBS to HBBG. Sixteen weeks after transplantation of edited human HSPCs into immunodeficient mice, the frequency of HBBG was 68% and hypoxia-induced sickling of bone marrow reticulocytes had decreased fivefold, indicating durable gene editing. To assess the physiological effects of HBBS base editing, we delivered ABE8e-NRCH and guide RNA into HSPCs from a humanized SCD mouse6 and then transplanted these cells into irradiated mice. After sixteen weeks, Makassar ß-globin represented 79% of ß-globin protein in blood, and hypoxia-induced sickling was reduced threefold. Mice that received base-edited HSPCs showed near-normal haematological parameters and reduced splenic pathology compared to mice that received unedited cells. Secondary transplantation of edited bone marrow confirmed that the gene editing was durable in long-term haematopoietic stem cells and showed that HBBS-to-HBBG editing of 20% or more is sufficient for phenotypic rescue. Base editing of human HSPCs avoided the p53 activation and larger deletions that have been observed following Cas9 nuclease treatment. These findings point towards a one-time autologous treatment for SCD that eliminates pathogenic HBBS, generates benign HBBG, and minimizes the undesired consequences of double-strand DNA breaks.


Assuntos
Adenina/metabolismo , Anemia Falciforme/genética , Anemia Falciforme/terapia , Edição de Genes , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/metabolismo , Globinas beta/genética , Animais , Antígenos CD34/metabolismo , Proteína 9 Associada à CRISPR/metabolismo , Modelos Animais de Doenças , Feminino , Terapia Genética , Genoma Humano/genética , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/patologia , Humanos , Masculino , Camundongos
18.
Mol Cell Biol ; 41(9): e0066820, 2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34180713

RESUMO

We previously demonstrated that the two paralogous RNA-binding proteins PCBP1 and PCBP2 are individually essential for mouse development: Pcbp1-null embryos are peri-implantation lethal, while Pcbp2-null embryos lose viability at midgestation. Midgestation Pcbp2-/- embryos revealed a complex phenotype that included loss of certain hematopoietic determinants. Whether PCBP2 directly contributes to erythropoietic differentiation and whether PCBP1 has a role in this process remained undetermined. Here, we selectively inactivated the genes encoding these two RNA-binding proteins during differentiation of the erythroid lineage in the developing mouse embryo. Individual inactivation of either locus failed to impact viability or blood formation. However, combined inactivation of the two loci resulted in midgestational repression of erythroid/hematopoietic gene expression, loss of blood formation, and fetal demise. Orthogonal ex vivo analyses of primary erythroid progenitors selectively depleted of these two RNA-binding proteins revealed that they mediate a combination of overlapping and isoform-specific impacts on hematopoietic lineage transcriptome, impacting both mRNA representation and exon splicing. These data lead us to conclude that PCBP1 and PCBP2 mediate functions critical to differentiation of the erythroid lineage.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Eritropoese , Proteínas de Ligação a RNA/metabolismo , Envelhecimento/fisiologia , Animais , Linhagem da Célula , Proteínas de Ligação a DNA/genética , Embrião de Mamíferos/metabolismo , Células Eritroides/citologia , Éxons/genética , Loci Gênicos , Células-Tronco Hematopoéticas/metabolismo , Camundongos , Splicing de RNA/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , Transcriptoma/genética
19.
Nat Commun ; 12(1): 3908, 2021 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-34162850

RESUMO

Though AsCas12a fills a crucial gap in the current genome editing toolbox, it exhibits relatively poor editing efficiency, restricting its overall utility. Here we isolate an engineered variant, "AsCas12a Ultra", that increased editing efficiency to nearly 100% at all sites examined in HSPCs, iPSCs, T cells, and NK cells. We show that AsCas12a Ultra maintains high on-target specificity thereby mitigating the risk for off-target editing and making it ideal for complex therapeutic genome editing applications. We achieved simultaneous targeting of three clinically relevant genes in T cells at >90% efficiency and demonstrated transgene knock-in efficiencies of up to 60%. We demonstrate site-specific knock-in of a CAR in NK cells, which afforded enhanced anti-tumor NK cell recognition, potentially enabling the next generation of allogeneic cell-based therapies in oncology. AsCas12a Ultra is an advanced CRISPR nuclease with significant advantages in basic research and in the production of gene edited cell medicines.


Assuntos
Acidaminococcus/enzimologia , Proteínas de Bactérias/metabolismo , Proteínas Associadas a CRISPR/metabolismo , Sistemas CRISPR-Cas , Endonucleases/metabolismo , Edição de Genes/métodos , Acidaminococcus/genética , Proteínas de Bactérias/genética , Proteínas Associadas a CRISPR/genética , Células Cultivadas , Endonucleases/genética , Células HEK293 , Células-Tronco Hematopoéticas/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células Jurkat , Células Matadoras Naturais/metabolismo , Reprodutibilidade dos Testes , Linfócitos T/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...