Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 41.781
Filtrar
1.
Nan Fang Yi Ke Da Xue Xue Bao ; 40(1): 110-117, 2020 Jan 30.
Artigo em Chinês | MEDLINE | ID: mdl-32376555

RESUMO

OBJECTIVE: To explore the effect of cyclophosphamide on hematopoietic stem cells (HSCs) in mice with iron overload. METHODS: Mouse models of iron overload were established in 30 male C57BL/6 mice by intraperitoneal injections of iron dextran at low (0.25 g/kg), moderate (0.5 g/kg), and high (1 g/kg) doses (n=10), with another 10 PBS-treated mice as the control group. The changes in body weight, liver, spleen and bone marrow of the mice were recorded, and serum level of ferritin was detected. The mice receiving a moderate dose of iron dextran were further divided into 8 groups for observation at different time points (D1, D2, D3, D4, D5, D6, D7, and D14 groups) and were given intraperitoneal injection of 50 mg/kg cyclophosphamide (Cy) for 2 consecutive days. Peripheral blood cells, bone marrow mononuclear cells (BMMNCs), and the frequencies of different HSCs (HPCs, HSCs, LT-HSCs) in the BMMNCs were monitored. The cell cycle distribution in the HSCs, level of reactive oxygen species and the microenvironment of the HSCs were analyzed using flow cytometry. RESULTS: Compared with the control mice, the mice with iron overload showed obvious weight loss with significantly increased serum ferritin level, enlargement of the liver and spleen, and iron deposition in the organs (P < 0.05). No significant changes were noted in the peripheral blood of the mice with iron overload. The cyclophosphamide-treated mice exhibited significantly decreased number of WBCs and lymphocyte ratio at days 1 to 4 (P < 0.05). The numbers of BMMNCs and HPCs in mice with iron overload did not show significant changes as compared with those in the control mice, but the numbers of HSCs and LTHSCs decreased significantly in the mice with iron overload (P < 0.05). In cyclophosphamide-treated mice, the number of HSCs increased since day 1 and reached the peak level on day 3 (P < 0.05). Compared with those in the control group, the HSCs did not exhibit significant changes in cell cycle distribution in mice with iron overload, but the proportion of G0/G1 cells decreased significantly in cyclophosphamide group since day 1 and reached the lowest level on day 3 (P < 0.05). CONCLUSIONS: Iron deposition in the bone marrow causes long- term damages of the HSCs in the bone marrow but does not induce obvious changes in the peripheral blood. In mice with iron overload, intraperitoneal injection of 50 mg/kg cyclophosphamide for two days promotes cell cycle changes of the resting HSCs to mobilize the HSCs, and this effect is the most obvious on day 4.


Assuntos
Ciclofosfamida/farmacologia , Células-Tronco Hematopoéticas/efeitos dos fármacos , Sobrecarga de Ferro , Animais , Células da Medula Óssea/efeitos dos fármacos , Ciclo Celular , Ferritinas/sangue , Masculino , Camundongos , Camundongos Endogâmicos C57BL
2.
FASEB J ; 34(6): 7247-7252, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32427393

RESUMO

The medical, public health, and scientific communities are grappling with monumental imperatives to contain COVID-19, develop effective vaccines, identify efficacious treatments for the infection and its complications, and find biomarkers that detect patients at risk of severe disease. The focus of this communication is on a potential biomarker, short telomere length (TL), that might serve to identify patients more likely to die from the SARS-CoV-2 infection, regardless of age. The common thread linking these patients is lymphopenia, which largely reflects a decline in the numbers of CD4/CD8 T cells but not B cells. These findings are consistent with data that lymphocyte TL dynamics impose a limit on T-cell proliferation. They suggest that T-cell lymphopoiesis might stall in individuals with short TL who are infected with SARS-CoV-2.


Assuntos
Betacoronavirus , Infecções por Coronavirus/patologia , Linfopenia/etiologia , Modelos Biológicos , Pneumonia Viral/patologia , Subpopulações de Linfócitos T/ultraestrutura , Encurtamento do Telômero , Telômero/ultraestrutura , Biomarcadores , Medula Óssea/patologia , Divisão Celular , Infecções por Coronavirus/genética , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/mortalidade , Progressão da Doença , Células-Tronco Hematopoéticas/patologia , Humanos , Ativação Linfocitária , Contagem de Linfócitos , Linfopenia/patologia , Linfopoese , Pandemias , Pneumonia Viral/genética , Pneumonia Viral/imunologia , Pneumonia Viral/mortalidade , Prognóstico , Risco
3.
PLoS One ; 15(4): e0229593, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32324791

RESUMO

Acute myeloid leukaemia (AML) is characterised by phenotypic heterogeneity, which we hypothesise is a consequence of deregulated differentiation with transcriptional reminiscence of the normal compartment or cell-of-origin. Here, we propose a classification system based on normal myeloid progenitor cell subset-associated gene signatures (MAGS) for individual assignments of AML subtypes. We generated a MAGS classifier including the progenitor compartments CD34+/CD38- for haematopoietic stem cells (HSCs), CD34+/CD38+/CD45RA- for megakaryocyte-erythroid progenitors (MEPs), and CD34+/CD38+/CD45RA+ for granulocytic-monocytic progenitors (GMPs) using regularised multinomial regression with three discrete outcomes and an elastic net penalty. The regularisation parameters were chosen by cross-validation, and MAGS assignment accuracy was validated in an independent data set (N = 38; accuracy = 0.79) of sorted normal myeloid subpopulations. The prognostic value of MAGS assignment was studied in two clinical cohorts (TCGA: N = 171; GSE6891: N = 520) and had a significant prognostic impact. Furthermore, multivariate Cox regression analysis using the MAGS subtype, FAB subtype, cytogenetics, molecular genetics, and age as explanatory variables showed independent prognostic value. Molecular characterisation of subtypes by differential gene expression analysis, gene set enrichment analysis, and mutation patterns indicated reduced proliferation and overrepresentation of RUNX1 and IDH2 mutations in the HSC subtype; increased proliferation and overrepresentation of CEBPA mutations in the MEP subtype; and innate immune activation and overrepresentation of WT1 mutations in the GMP subtype. We present a differentiation-dependent classification system for AML subtypes with distinct pathogenetic and prognostic importance that can help identify candidates poorly responding to combination chemotherapy and potentially guide alternative treatments.


Assuntos
Células-Tronco Hematopoéticas/metabolismo , Leucemia Mieloide Aguda/genética , Células Mieloides/metabolismo , Células-Tronco/metabolismo , ADP-Ribosil Ciclase 1/genética , Antígenos CD34/genética , Diferenciação Celular/genética , Linhagem da Célula/genética , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Células-Tronco Hematopoéticas/patologia , Humanos , Isocitrato Desidrogenase/genética , Leucemia Mieloide Aguda/patologia , Antígenos Comuns de Leucócito/genética , Masculino , Pessoa de Meia-Idade , Mutação/genética , Células Mieloides/patologia , Análise de Componente Principal , Análise de Regressão , Células-Tronco/patologia , Proteínas WT1/genética
5.
Nat Immunol ; 21(5): 535-545, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32313245

RESUMO

Despite evidence of chronic inflammation in myelodysplastic syndrome (MDS) and cell-intrinsic dysregulation of Toll-like receptor (TLR) signaling in MDS hematopoietic stem and progenitor cells (HSPCs), the mechanisms responsible for the competitive advantage of MDS HSPCs in an inflammatory milieu over normal HSPCs remain poorly defined. Here, we found that chronic inflammation was a determinant for the competitive advantage of MDS HSPCs and for disease progression. The cell-intrinsic response of MDS HSPCs, which involves signaling through the noncanonical NF-κB pathway, protected these cells from chronic inflammation as compared to normal HSPCs. In response to inflammation, MDS HSPCs switched from canonical to noncanonical NF-κB signaling, a process that was dependent on TLR-TRAF6-mediated activation of A20. The competitive advantage of TLR-TRAF6-primed HSPCs could be restored by deletion of A20 or inhibition of the noncanonical NF-κB pathway. These findings uncover the mechanistic basis for the clonal dominance of MDS HSPCs and indicate that interfering with noncanonical NF-κB signaling could prevent MDS progression.


Assuntos
Células-Tronco Hematopoéticas/fisiologia , Inflamação/imunologia , Síndromes Mielodisplásicas/imunologia , NF-kappa B/metabolismo , Fator 6 Associado a Receptor de TNF/metabolismo , Idoso , Animais , Diferenciação Celular , Células Cultivadas , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Mielopoese , NF-kappa B/genética , Transdução de Sinais , Fator 6 Associado a Receptor de TNF/genética , Receptores Toll-Like/metabolismo , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/genética , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/metabolismo
6.
Science ; 367(6485): 1449-1454, 2020 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-32217721

RESUMO

Somatic mutations acquired in healthy tissues as we age are major determinants of cancer risk. Whether variants confer a fitness advantage or rise to detectable frequencies by chance remains largely unknown. Blood sequencing data from ~50,000 individuals reveal how mutation, genetic drift, and fitness shape the genetic diversity of healthy blood (clonal hematopoiesis). We show that positive selection, not drift, is the major force shaping clonal hematopoiesis, provide bounds on the number of hematopoietic stem cells, and quantify the fitness advantages of key pathogenic variants, at single-nucleotide resolution, as well as the distribution of fitness effects (fitness landscape) within commonly mutated driver genes. These data are consistent with clonal hematopoiesis being driven by a continuing risk of mutations and clonal expansions that become increasingly detectable with age.


Assuntos
Envelhecimento , Evolução Biológica , Deriva Genética , Aptidão Genética , Hematopoese/genética , Seleção Genética , Frequência do Gene , Genética Populacional , Células-Tronco Hematopoéticas/citologia , Humanos , Modelos Genéticos , Mutação , Taxa de Mutação
8.
Mol Immunol ; 120: 122-129, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32114182

RESUMO

Dendritic cells (DCs) orchestrate adaptive immune responses. In healthy individuals, DCs are drivers and fine-tuners of T cell responses directed against invading pathogens or cancer cells. In parallel, DCs control autoreactive T cells, thereby maintaining T cell tolerance. Under various disease conditions, a disruption of this delicate balance can lead to chronic infections, tumor evasion, or autoimmunity. While great efforts have been made to unravel the origin and development of this powerful cell type in mice, only little is known about the ontogeny of human DCs. Here, we summarize the current understanding of the developmental path of DCs from hematopoietic stem cells to fully functional DCs in their local tissue environment and provide a template for the identification of DCs across various tissues.


Assuntos
Células Dendríticas/citologia , Células Dendríticas/imunologia , Animais , Autoimunidade , Diferenciação Celular/imunologia , Microambiente Celular/imunologia , Células Dendríticas/classificação , Células-Tronco Hematopoéticas/classificação , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/imunologia , Humanos , Tolerância Imunológica , Camundongos , Modelos Imunológicos , Especificidade de Órgãos , Fenótipo
9.
Cancer Sci ; 111(5): 1851-1855, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32216001

RESUMO

Gene rearrangements of MLL/KMT2A or RUNX1 are the major cause of therapy-related leukemia. Moreover, MLL rearrangements are the major cause of infant leukemia, and RUNX1 rearrangements are frequently detected in cord blood. These genes are sensitive to topoisomerase II inhibitors, and various genes have been identified as potential fusion partners. However, fetal exposure to these inhibitors is rare. Therefore, we postulated that even a proliferation signal itself might induce gene rearrangements in hematopoietic stem cells. To test this hypothesis, we detected gene rearrangements in etoposide-treated or non-treated CD34+ cells cultured with cytokines using inverse PCR. In the etoposide-treated cells, variable-sized rearrangement bands were detected in the RUNX1 and MLL genes at 3 hours of culture, which decreased after 7 days. However, more rearrangement bands were detected in the non-treated cells at 7 days of culture. Such gene rearrangements were also detected in peripheral blood stem cells mobilized by cytokines for transplantation. However, none of these rearranged genes encoded the leukemogenic oncogene, and the cells with rearrangements did not expand. These findings suggest that MLL and RUNX1 rearrangements, which occur with very low frequency in normal hematopoietic progenitor cells, may be induced under cytokine stimulation. Most of the cells with gene rearrangements are likely eliminated, except for leukemia-associated gene rearrangements, resulting in the low prevalence of leukemia development.


Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/genética , Citocinas/farmacologia , Rearranjo Gênico/efeitos dos fármacos , Células-Tronco Hematopoéticas/efeitos dos fármacos , Histona-Lisina N-Metiltransferase/genética , Proteína de Leucina Linfoide-Mieloide/genética , Idoso , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Etoposídeo/farmacologia , Células-Tronco Hematopoéticas/metabolismo , Humanos , Linfoma Difuso de Grandes Células B/patologia , Pessoa de Meia-Idade , Células-Tronco de Sangue Periférico/efeitos dos fármacos , Células-Tronco de Sangue Periférico/metabolismo , Inibidores da Topoisomerase II/farmacologia
10.
PLoS One ; 15(3): e0228878, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32134938

RESUMO

We studied a cohort of 367 healthy related donors who volunteered to donate their hematopoietic stem cells for allogeneic transplantation. All donors were homogeneously cared for at a single institution, and received rhG-CSF as a mobilization treatment prior to undergoing apheresis. Peripheral blood CD34+ cell counts were used as the main surrogate marker for rhG-CSF induced mobilization. We searched whether inter-individual variations in known genetic polymorphisms located in genes whose products are functionally important for mobilization, could affect the extent of CD34+ mobilization, either individually or in combination. We found little or no influence of individual SNPs or haplotypes for the SDF1, CXCR4, VCAM and VLA4 genes, whether using CD34+ cell counts as a continuous or a categorical variable. Simple clinical characteristics describing donors such as body mass index, age and possibly sex are more potent predictors of stem cell mobilization. The size of our cohort remains relatively small for genetic analyses, however compares favorably with cohorts analyzed in previously published reports suggesting associations of genetic traits to response to rhG-CSF; notwithstanding this limitation, our data do not support the use of genetic analyses when the choice exists of several potential donors for a given patient.


Assuntos
Quimiocina CXCL12/genética , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Integrina alfa4beta1/genética , Polimorfismo de Nucleotídeo Único , Receptores CXCR4/genética , Molécula 1 de Adesão de Célula Vascular/genética , Adulto , Idoso , Feminino , Fator Estimulador de Colônias de Granulócitos/farmacologia , Mobilização de Células-Tronco Hematopoéticas , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/efeitos dos fármacos , Humanos , Doadores Vivos , Masculino , Pessoa de Meia-Idade , Transplante Homólogo , Adulto Jovem
11.
Nat Med ; 26(3): 408-417, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32161403

RESUMO

The diagnosis of lymphomas and leukemias requires hematopathologists to integrate microscopically visible cellular morphology with antibody-identified cell surface molecule expression. To merge these into one high-throughput, highly multiplexed, single-cell assay, we quantify cell morphological features by their underlying, antibody-measurable molecular components, which empowers mass cytometers to 'see' like pathologists. When applied to 71 diverse clinical samples, single-cell morphometric profiling reveals robust and distinct patterns of 'morphometric' markers for each major cell type. Individually, lamin B1 highlights acute leukemias, lamin A/C helps distinguish normal from neoplastic mature T cells, and VAMP-7 recapitulates light-cytometric side scatter. Combined with machine learning, morphometric markers form intuitive visualizations of normal and neoplastic cellular distribution and differentiation. When recalibrated for myelomonocytic blast enumeration, this approach is superior to flow cytometry and comparable to expert microscopy, bypassing years of specialized training. The contextualization of traditional surface markers on independent morphometric frameworks permits more sensitive and automated diagnosis of complex hematopoietic diseases.


Assuntos
Leucemia/diagnóstico , Leucemia/patologia , Linfoma/diagnóstico , Linfoma/patologia , Análise de Célula Única/métodos , Células-Tronco Hematopoéticas/patologia , Humanos , Laminas/metabolismo , Antígenos Comuns de Leucócito/metabolismo , Células Mieloides/patologia , Proteínas R-SNARE/metabolismo
12.
Nat Genet ; 52(4): 378-387, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32203468

RESUMO

Mutations in genes involved in DNA methylation (DNAme; for example, TET2 and DNMT3A) are frequently observed in hematological malignancies1-3 and clonal hematopoiesis4,5. Applying single-cell sequencing to murine hematopoietic stem and progenitor cells, we observed that these mutations disrupt hematopoietic differentiation, causing opposite shifts in the frequencies of erythroid versus myelomonocytic progenitors following Tet2 or Dnmt3a loss. Notably, these shifts trace back to transcriptional priming skews in uncommitted hematopoietic stem cells. To reconcile genome-wide DNAme changes with specific erythroid versus myelomonocytic skews, we provide evidence in support of differential sensitivity of transcription factors due to biases in CpG enrichment in their binding motif. Single-cell transcriptomes with targeted genotyping showed similar skews in transcriptional priming of DNMT3A-mutated human clonal hematopoiesis bone marrow progenitors. These data show that DNAme shapes the topography of hematopoietic differentiation, and support a model in which genome-wide methylation changes are transduced to differentiation skews through biases in CpG enrichment of the transcription factor binding motif.


Assuntos
Diferenciação Celular/genética , Metilação de DNA/genética , Hematopoese/genética , Animais , DNA (Citosina-5-)-Metiltransferases/genética , Proteínas de Ligação a DNA/genética , Células-Tronco Hematopoéticas/fisiologia , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Mutação/genética , Transcrição Genética/genética , Transcriptoma/genética
13.
Nature ; 581(7808): 303-309, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32214235

RESUMO

Single-cell analysis is a valuable tool for dissecting cellular heterogeneity in complex systems1. However, a comprehensive single-cell atlas has not been achieved for humans. Here we use single-cell mRNA sequencing to determine the cell-type composition of all major human organs and construct a scheme for the human cell landscape (HCL). We have uncovered a single-cell hierarchy for many tissues that have not been well characterized. We established a 'single-cell HCL analysis' pipeline that helps to define human cell identity. Finally, we performed a single-cell comparative analysis of landscapes from human and mouse to identify conserved genetic networks. We found that stem and progenitor cells exhibit strong transcriptomic stochasticity, whereas differentiated cells are more distinct. Our results provide a useful resource for the study of human biology.


Assuntos
Células/citologia , Células/metabolismo , Análise de Célula Única/métodos , Adulto , Animais , Grupo com Ancestrais do Continente Asiático , Diferenciação Celular , Linhagem Celular , Separação Celular , China , Bases de Dados Factuais , Corpos Embrioides/citologia , Corpos Embrioides/metabolismo , Grupos Étnicos , Feto/citologia , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Humanos , Imunidade , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/metabolismo , Camundongos , Especificidade de Órgãos , RNA Mensageiro/análise , RNA Mensageiro/genética , Análise de Sequência de RNA , Análise de Célula Única/instrumentação , Processos Estocásticos
14.
PLoS One ; 15(3): e0228221, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32155151

RESUMO

Inflammatory bowel diseases (IBD) are complex, multifactorial disorders characterized by chronic relapsing intestinal inflammation. IBD is diagnosed around 1 in 1000 individuals in Western countries with globally increasing incident rates. Association studies have identified hundreds of genes that are linked to IBD and potentially regulate its pathology. The further dissection of the genetic network underlining IBD pathogenesis and pathophysiology is hindered by the limited capacity to functionally characterize each genetic association, including generating knockout animal models for every associated gene. Cutting-edge CRISPR/Cas9-based technology may transform the field of IBD research by efficiently and effectively introducing genetic alterations. In the present study, we used CRISPR/Cas9-based technologies to genetically modify hematopoietic stem cells. Through cell sorting and bone marrow transplantation, we established a system to knock out target gene expression by over 90% in the immune system of reconstituted animals. Using a CD40-mediated colitis model, we further validated our CRISPR/Cas9-based platform for investigating gene function in experimental IBD. In doing so, we developed a model system that delivers genetically modified mice in a manner much faster than conventional methodology, significantly reducing the time from target identification to in vivo target validation and expediting drug development.


Assuntos
Antígenos CD40/imunologia , Sistemas CRISPR-Cas/genética , Células-Tronco Hematopoéticas/metabolismo , Animais , Antígenos CD40/metabolismo , Colite/imunologia , Colite/terapia , Regulação da Expressão Gênica , Transplante de Células-Tronco Hematopoéticas , Camundongos
15.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 28(1): 320-324, 2020 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-32027296

RESUMO

Abstract  Currently, hematopoietic stem cell (HSC) transplantation is widely used in the therapy of hematological malignancies, non-malignant refractory anemia, genetic diseases and certain tumors with satisfactory therapeutic efficacy. HSC sources used for transplantation include bone marrow, mobilized peripheral blood and neonate umbilical cord blood. However, for many patients, sufficient number of human leukocyte antigen (HLA) -matched HSC cannot be found for transplantation, because the number of HSC in these tissues is small and HLA-identical donors are rare. Thus, in vitro generation of HSC has recently been focused. At present, the origin of HSC is hPSC, including hESC and hiPSC, which is worth to be the new origin of HSC transplantation. However, to generate functional hematopoietic stem cells which have efficient multi-lineage differentiation and in vivo engraftment potentials still is a big challenge to be confronted. In this review, the recent technical progress in HSC generation is summarizd, and the problems to be solved and new challenges to be confronted were discussed.


Assuntos
Neoplasias Hematológicas , Transplante de Células-Tronco Hematopoéticas , Medula Óssea , Sangue Fetal , Células-Tronco Hematopoéticas , Humanos
16.
Nat Immunol ; 21(3): 261-273, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32066955

RESUMO

Crosstalk between mesenchymal stromal cells (MSCs) and hematopoietic stem cells (HSCs) is essential for hematopoietic homeostasis and lineage output. Here, we investigate how transcriptional changes in bone marrow (BM) MSCs result in long-lasting effects on HSCs. Single-cell analysis of Cxcl12-abundant reticular (CAR) cells and PDGFRα+Sca1+ (PαS) cells revealed an extensive cellular heterogeneity but uniform expression of the transcription factor gene Ebf1. Conditional deletion of Ebf1 in these MSCs altered their cellular composition, chromatin structure and gene expression profiles, including the reduced expression of adhesion-related genes. Functionally, the stromal-specific Ebf1 inactivation results in impaired adhesion of HSCs, leading to reduced quiescence and diminished myeloid output. Most notably, HSCs residing in the Ebf1-deficient niche underwent changes in their cellular composition and chromatin structure that persist in serial transplantations. Thus, genetic alterations in the BM niche lead to long-term functional changes of HSCs.


Assuntos
Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Transativadores/deficiência , Animais , Adesão Celular/genética , Adesão Celular/fisiologia , Autorrenovação Celular/genética , Autorrenovação Celular/fisiologia , Cromatina/genética , Feminino , Hematopoese/genética , Hematopoese/fisiologia , Transplante de Células-Tronco Hematopoéticas , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Análise de Célula Única , Nicho de Células-Tronco/genética , Nicho de Células-Tronco/fisiologia , Transativadores/genética , Transcriptoma
17.
Nat Neurosci ; 23(3): 351-362, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32042176

RESUMO

Monocyte-derived and tissue-resident macrophages are ontogenetically distinct components of the innate immune system. Assessment of their respective functions in pathology is complicated by changes to the macrophage phenotype during inflammation. Here we find that Cxcr4-CreER enables permanent genetic labeling of hematopoietic stem cells (HSCs) and distinguishes HSC-derived monocytes from microglia and other tissue-resident macrophages. By combining Cxcr4-CreER-mediated lineage tracing with Cxcr4 inhibition or conditional Cxcr4 ablation in photothrombotic stroke, we find that Cxcr4 promotes initial monocyte infiltration and subsequent territorial restriction of monocyte-derived macrophages to infarct tissue. After transient focal ischemia, Cxcr4 deficiency reduces monocyte infiltration and blunts the expression of pattern recognition and defense response genes in monocyte-derived macrophages. This is associated with an altered microglial response and deteriorated outcomes. Thus, Cxcr4 is essential for an innate-immune-system-mediated defense response after cerebral ischemia. We further propose Cxcr4-CreER as a universal tool to study functions of HSC-derived cells.


Assuntos
Isquemia Encefálica/imunologia , Células-Tronco Hematopoéticas/imunologia , Microglia/imunologia , Monócitos/imunologia , Receptores CXCR4/metabolismo , Acidente Vascular Cerebral/imunologia , Animais , Isquemia Encefálica/patologia , Linhagem da Célula , Infarto Cerebral/imunologia , Infarto Cerebral/patologia , Células-Tronco Hematopoéticas/patologia , Imunidade Inata/genética , Ataque Isquêmico Transitório/imunologia , Ataque Isquêmico Transitório/patologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia/patologia , Monócitos/patologia , Receptores CXCR4/genética , Receptores CXCR4/imunologia , Acidente Vascular Cerebral/patologia , Trombose/patologia , Resultado do Tratamento
18.
PLoS One ; 15(2): e0228674, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32040489

RESUMO

In order to accomplish their physiological functions leukocytes have the capability to migrate. As a prerequisite they need to adopt a polarized cell shape, forming a leading edge at the front and a uropod at rear pole. In this study we explored the capability of chronic lymphocytic leukaemia (CLL) cells to adopt this leukocyte-specific migration phenotype. Furthermore, we studied the impact of the Toll-like receptor 9 (TLR9) agonists CpGs type A, B and C and the antagonist oligodesoxynucleotide (ODN) INH-18 on the cell polarization and migration process of primary human CLL cells. Upon cultivation, a portion of purified CLL cells adopted polarized cell shapes spontaneously (range 10-38%). Stimulation with CpG ODNs type B (ODN 2006) and CpGs type C (ODN 2395) significantly increased the frequency of morphologically polarized CLL cells, while ODN INH-18 was hardly able to act antagonistically. Like in human hematopoietic stem and progenitor cells, in morphologically polarized CLL cells CXCR4 was redistributed to the leading edge and CD50 to the uropod. Coupled to the increased frequencies of morphologically polarized cells, CpGs type B and C stimulated CLL cells showed higher migration activities in vitro and following intravenous injection higher homing frequencies to the bone marrow of immunocompromised NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice. Thus, presumably independent of TLR-9 signaling, CpGs type B and C promote the cellular polarization process of CLL cells and their ability to migrate in vitro and in vivo.


Assuntos
Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/genética , Oligodesoxirribonucleotídeos/farmacologia , Animais , Células da Medula Óssea/citologia , Membrana Celular/metabolismo , Movimento Celular , Proliferação de Células , Forma Celular , Células Cultivadas , Células-Tronco Hematopoéticas/citologia , Humanos , Camundongos , Camundongos Endogâmicos NOD , Transplante de Neoplasias , Receptores CXCR4/metabolismo , Receptor Toll-Like 9/metabolismo
19.
Nucleic Acids Res ; 48(6): 2956-2968, 2020 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-32025719

RESUMO

Protein arginine methyltransferase 5 (PRMT5) catalyzes the symmetric di-methylation of arginine residues in histones H3 and H4, marks that are generally associated with transcriptional repression. However, we found that PRMT5 inhibition or depletion led to more genes being downregulated than upregulated, indicating that PRMT5 can also act as a transcriptional activator. Indeed, the global level of histone H3K27me3 increases in PRMT5 deficient cells. Although PRMT5 does not directly affect PRC2 enzymatic activity, methylation of histone H3 by PRMT5 abrogates its subsequent methylation by PRC2. Treating AML cells with an EZH2 inhibitor partially restored the expression of approximately 50% of the genes that are initially downregulated by PRMT5 inhibition, suggesting that the increased H3K27me3 could directly or indirectly contribute to the transcription repression of these genes. Indeed, ChIP-sequencing analysis confirmed an increase in the H3K27me3 level at the promoter region of a quarter of these genes in PRMT5-inhibited cells. Interestingly, the anti-proliferative effect of PRMT5 inhibition was also partially rescued by treatment with an EZH2 inhibitor in several leukemia cell lines. Thus, PRMT5-mediated crosstalk between histone marks contributes to its functional effects.


Assuntos
Arginina/metabolismo , Histonas/metabolismo , Proteínas do Grupo Polycomb/metabolismo , Proteína-Arginina N-Metiltransferases/metabolismo , Transcrição Genética , Animais , Ciclo Celular/genética , Linhagem Celular Tumoral , Deleção de Genes , Regulação da Expressão Gênica , Células-Tronco Hematopoéticas/metabolismo , Metilação , Camundongos Knockout , Modelos Biológicos , Nucleossomos/metabolismo , Proteína-Arginina N-Metiltransferases/antagonistas & inibidores
20.
Nat Commun ; 11(1): 666, 2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-32015345

RESUMO

Inflammatory signals arising from the microenvironment have emerged as critical regulators of hematopoietic stem cell (HSC) function during diverse processes including embryonic development, infectious diseases, and myelosuppressive injuries caused by irradiation and chemotherapy. However, the contributions of cellular subsets within the microenvironment that elicit niche-driven inflammation remain poorly understood. Here, we identify endothelial cells as a crucial component in driving bone marrow (BM) inflammation and HSC dysfunction observed following myelosuppression. We demonstrate that sustained activation of endothelial MAPK causes NF-κB-dependent inflammatory stress response within the BM, leading to significant HSC dysfunction including loss of engraftment ability and a myeloid-biased output. These phenotypes are resolved upon inhibition of endothelial NF-κB signaling. We identify SCGF as a niche-derived factor that suppresses BM inflammation and enhances hematopoietic recovery following myelosuppression. Our findings demonstrate that chronic endothelial inflammation adversely impacts niche activity and HSC function which is reversible upon suppression of inflammation.


Assuntos
Células Endoteliais/metabolismo , Hematopoese/fisiologia , Fatores de Crescimento de Células Hematopoéticas/metabolismo , Lectinas Tipo C/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , NF-kappa B/metabolismo , Animais , Antígenos CD , Medula Óssea , Caderinas , Feminino , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas , Inflamação , Masculino , Camundongos , Transdução de Sinais , Transplante Autólogo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA