RESUMO
Autonomic nerves control organ function through the sympathetic and parasympathetic branches, which have opposite effects. In the bone marrow, sympathetic (adrenergic) nerves promote hematopoiesis; however, how parasympathetic (cholinergic) signals modulate hematopoiesis is unclear. Here, we show that B lymphocytes are an important source of acetylcholine, a neurotransmitter of the parasympathetic nervous system, which reduced hematopoiesis. Single-cell RNA sequencing identified nine clusters of cells that expressed the cholinergic α7 nicotinic receptor (Chrna7) in the bone marrow stem cell niche, including endothelial and mesenchymal stromal cells (MSCs). Deletion of B cell-derived acetylcholine resulted in the differential expression of various genes, including Cxcl12 in leptin receptor+ (LepR+) stromal cells. Pharmacologic inhibition of acetylcholine signaling increased the systemic supply of inflammatory myeloid cells in mice and humans with cardiovascular disease.
Assuntos
Acetilcolina , Hematopoese , Animais , Linfócitos B , Colinérgicos , Hematopoese/genética , Camundongos , Nicho de Células-TroncoRESUMO
Stroma is a poorly defined non-parenchymal component of virtually every organ with key roles in organ development, homeostasis, and repair. Studies of the bone marrow stroma have defined individual populations in the stem cell niche regulating hematopoietic regeneration and capable of initiating leukemia. Here, we use single-cell RNA sequencing (scRNA-seq) to define a cellular taxonomy of the mouse bone marrow stroma and its perturbation by malignancy. We identified seventeen stromal subsets expressing distinct hematopoietic regulatory genes spanning new fibroblastic and osteoblastic subpopulations including distinct osteoblast differentiation trajectories. Emerging acute myeloid leukemia impaired mesenchymal osteogenic differentiation and reduced regulatory molecules necessary for normal hematopoiesis. These data suggest that tissue stroma responds to malignant cells by disadvantaging normal parenchymal cells. Our taxonomy of the stromal compartment provides a comprehensive bone marrow cell census and experimental support for cancer cell crosstalk with specific stromal elements to impair normal tissue function and thereby enable emergent cancer.
Assuntos
Células da Medula Óssea/metabolismo , Diferenciação Celular , Homeostase , Leucemia Mieloide Aguda/metabolismo , Osteoblastos/metabolismo , Osteogênese , Microambiente Tumoral , Animais , Células da Medula Óssea/patologia , Humanos , Leucemia Mieloide Aguda/patologia , Camundongos , Osteoblastos/patologia , Células Estromais/metabolismo , Células Estromais/patologiaRESUMO
Hematopoietic stem cell transplantation is a potential curative therapy for malignant and nonmalignant diseases. Improving the efficiency of stem cell collection and the quality of the cells acquired can broaden the donor pool and improve patient outcomes. We developed a rapid stem cell mobilization regimen utilizing a unique CXCR2 agonist, GROß, and the CXCR4 antagonist AMD3100. A single injection of both agents resulted in stem cell mobilization peaking within 15 min that was equivalent in magnitude to a standard multi-day regimen of granulocyte colony-stimulating factor (G-CSF). Mechanistic studies determined that rapid mobilization results from synergistic signaling on neutrophils, resulting in enhanced MMP-9 release, and unexpectedly revealed genetic polymorphisms in MMP-9 that alter activity. This mobilization regimen results in preferential trafficking of stem cells that demonstrate a higher engraftment efficiency than those mobilized by G-CSF. Our studies suggest a potential new strategy for the rapid collection of an improved hematopoietic graft.
Assuntos
Mobilização de Células-Tronco Hematopoéticas/métodos , Transplante de Células-Tronco Hematopoéticas/métodos , Células-Tronco Hematopoéticas/imunologia , Adulto , Animais , Benzilaminas , Quimiocina CXCL2/farmacologia , Ciclamos , Feminino , Células-Tronco Hematopoéticas/efeitos dos fármacos , Compostos Heterocíclicos/farmacologia , Humanos , Masculino , Metaloproteinase 9 da Matriz/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Endogâmicos ICR , Polimorfismo GenéticoRESUMO
Regulation of stem and progenitor cell populations is critical in the development, maintenance, and regeneration of tissues. Here, we define a novel mechanism by which a niche-secreted RNase, angiogenin (ANG), distinctively alters the functional characteristics of primitive hematopoietic stem/progenitor cells (HSPCs) compared with lineage-committed myeloid-restricted progenitor (MyePro) cells. Specifically, ANG reduces the proliferative capacity of HSPC while simultaneously increasing proliferation of MyePro cells. Mechanistically, ANG induces cell-type-specific RNA-processing events: tRNA-derived stress-induced small RNA (tiRNA) generation in HSPCs and rRNA induction in MyePro cells, leading to respective reduction and increase in protein synthesis. Recombinant ANG protein improves survival of irradiated animals and enhances hematopoietic regeneration of mouse and human HSPCs in transplantation. Thus, ANG plays a non-cell-autonomous role in regulation of hematopoiesis by simultaneously preserving HSPC stemness and promoting MyePro proliferation. These cell-type-specific functions of ANG suggest considerable therapeutic potential.
Assuntos
Células-Tronco Hematopoéticas/metabolismo , Ribonuclease Pancreático/metabolismo , Animais , Proliferação de Células , Hematopoese , Células-Tronco Hematopoéticas/citologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Células Mieloides/metabolismo , RNA de Transferência/metabolismo , RNA não Traduzido/metabolismoRESUMO
Stem cells determine homeostasis and repair of many tissues and are increasingly recognized as functionally heterogeneous. To define the extent of-and molecular basis for-heterogeneity, we overlaid functional, transcriptional, and epigenetic attributes of hematopoietic stem cells (HSCs) at a clonal level using endogenous fluorescent tagging. Endogenous HSC had clone-specific functional attributes over time in vivo. The intra-clonal behaviors were highly stereotypic, conserved under the stress of transplantation, inflammation, and genotoxic injury, and associated with distinctive transcriptional, DNA methylation, and chromatin accessibility patterns. Further, HSC function corresponded to epigenetic configuration but not always to transcriptional state. Therefore, hematopoiesis under homeostatic and stress conditions represents the integrated action of highly heterogeneous clones of HSC with epigenetically scripted behaviors. This high degree of epigenetically driven cell autonomy among HSCs implies that refinement of the concepts of stem cell plasticity and of the stem cell niche is warranted.
Assuntos
Epigenômica , Células-Tronco Hematopoéticas/citologia , Animais , Linhagem da Célula , Células Clonais/citologia , Fluorescência , Hematopoese , Inflamação/patologia , Camundongos , Transcrição GênicaRESUMO
While acute myeloid leukemia (AML) comprises many disparate genetic subtypes, one shared hallmark is the arrest of leukemic myeloblasts at an immature and self-renewing stage of development. Therapies that overcome differentiation arrest represent a powerful treatment strategy. We leveraged the observation that the majority of AML, despite their genetically heterogeneity, share in the expression of HoxA9, a gene normally downregulated during myeloid differentiation. Using a conditional HoxA9 model system, we performed a high-throughput phenotypic screen and defined compounds that overcame differentiation blockade. Target identification led to the unanticipated discovery that inhibition of the enzyme dihydroorotate dehydrogenase (DHODH) enables myeloid differentiation in human and mouse AML models. In vivo, DHODH inhibitors reduced leukemic cell burden, decreased levels of leukemia-initiating cells, and improved survival. These data demonstrate the role of DHODH as a metabolic regulator of differentiation and point to its inhibition as a strategy for overcoming differentiation blockade in AML.
Assuntos
Antineoplásicos/uso terapêutico , Inibidores Enzimáticos/uso terapêutico , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/patologia , Terapia de Alvo Molecular , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/antagonistas & inibidores , Animais , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Diferenciação Celular , Di-Hidro-Orotato Desidrogenase , Inibidores Enzimáticos/química , Inibidores Enzimáticos/isolamento & purificação , Ensaios de Triagem em Larga Escala , Proteínas de Homeodomínio/genética , Humanos , Leucemia Mieloide Aguda/genética , Camundongos , Células Mieloides/patologia , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/metabolismo , Pirimidinas/metabolismo , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/isolamento & purificação , Bibliotecas de Moléculas Pequenas/uso terapêutico , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The multiple cell types comprising blood have been thought to emerge from progenitors with progressively narrower lineage options. New data suggest that lineage fate may be determined earlier than thought and that myeloid progenitor populations are aggregates of individual lineage-restricted cells.
Assuntos
Linhagem da Célula , Hematopoese , Células Progenitoras Mieloides/citologia , Células Progenitoras Mieloides/metabolismo , Análise de Célula Única , Transcriptoma , AnimaisRESUMO
No metazoan cell survives on its own, absent the signals and support of its milieu. For multicellular life with specialized tissues to persist, organization is everything and so defining the association of position with cell state is critical to understanding how tissues function, maintain, and repair. This review focuses specifically on place for progenitor and stem cells. Especially emphasized are hematopoietic cells that balance free movement and stable position and where concepts of regulatory interrelationships have been shown with some precision. It reviews classical and emerging concepts of the niche, particularly considering how niche functions may participate in neoplastic disease.
Assuntos
Células-Tronco Hematopoéticas/citologia , Nicho de Células-Tronco , Células-Tronco/citologia , Animais , Humanos , Neoplasias/patologia , Transdução de SinaisRESUMO
Although stem cells are subject to niche control, evidence is emerging that they also contribute to generating the niche through their offspring. Using the hair follicle as a model, Hsu at al. demonstrate that the transient-amplifying cells, downstream of stem cells and well-known cell producers, signal back to stem cells to maintain long-term regenerative capacity.
Assuntos
Folículo Piloso/citologia , Cabelo/citologia , Cabelo/fisiologia , Nicho de Células-Tronco , Células-Tronco/citologia , AnimaisRESUMO
The balance between oxidative and nonoxidative glucose metabolism is essential for a number of pathophysiological processes. By deleting enzymes that affect aerobic glycolysis with different potencies, we examine how modulating glucose metabolism specifically affects hematopoietic and leukemic cell populations. We find that a deficiency in the M2 pyruvate kinase isoform (PKM2) reduces the levels of metabolic intermediates important for biosynthesis and impairs progenitor function without perturbing hematopoietic stem cells (HSCs), whereas lactate dehydrogenase A (LDHA) deletion significantly inhibits the function of both HSCs and progenitors during hematopoiesis. In contrast, leukemia initiation by transforming alleles putatively affecting either HSCs or progenitors is inhibited in the absence of either PKM2 or LDHA, indicating that the cell-state-specific responses to metabolic manipulation in hematopoiesis do not apply to the setting of leukemia. This finding suggests that fine-tuning the level of glycolysis may be explored therapeutically for treating leukemia while preserving HSC function.
Assuntos
Glicólise , Hematopoese , Leucemia/metabolismo , Animais , Deleção de Genes , Células-Tronco Hematopoéticas/metabolismo , Humanos , Isoenzimas/metabolismo , L-Lactato Desidrogenase/metabolismo , Lactato Desidrogenase 5 , Camundongos , Camundongos Congênicos , Camundongos Endogâmicos C57BL , Piruvato Quinase/genética , Piruvato Quinase/metabolismoRESUMO
Blood cell production is tightly regulated by cell-intrinsic mechanisms and environmental factors. The study by Utpal Banerjee and colleagues and colleagues reveals that, in Drosophila, olfactory signals control hematopoietic progenitor maintenance, thus uncovering a physiological link between sensory perception and hematopoietic response to environmental stress.
Assuntos
Drosophila melanogaster/citologia , Drosophila melanogaster/fisiologia , Hemolinfa/citologia , Células-Tronco/citologia , AnimaisRESUMO
X chromosome aneuploidies have long been associated with human cancers, but causality has not been established. In mammals, X chromosome inactivation (XCI) is triggered by Xist RNA to equalize gene expression between the sexes. Here we delete Xist in the blood compartment of mice and demonstrate that mutant females develop a highly aggressive myeloproliferative neoplasm and myelodysplastic syndrome (mixed MPN/MDS) with 100% penetrance. Significant disease components include primary myelofibrosis, leukemia, histiocytic sarcoma, and vasculitis. Xist-deficient hematopoietic stem cells (HSCs) show aberrant maturation and age-dependent loss. Reconstitution experiments indicate that MPN/MDS and myelofibrosis are of hematopoietic rather than stromal origin. We propose that Xist loss results in X reactivation and consequent genome-wide changes that lead to cancer, thereby causally linking the X chromosome to cancer in mice. Thus, Xist RNA not only is required to maintain XCI but also suppresses cancer in vivo.
Assuntos
Genes Supressores de Tumor , Síndromes Mielodisplásicas/genética , Transtornos Mieloproliferativos/genética , RNA Longo não Codificante/genética , Animais , Medula Óssea/fisiopatologia , Feminino , Genes Letais , Células-Tronco Hematopoéticas/metabolismo , Masculino , Camundongos , Mielofibrose Primária/genética , Esplenomegalia/metabolismo , Inativação do Cromossomo XRESUMO
Transcription factor activity and turnover are functionally linked, but the global patterns by which DNA-bound regulators are eliminated remain poorly understood. We established an assay to define the chromosomal location of DNA-associated proteins that are slated for degradation by the ubiquitin-proteasome system. The genome-wide map described here ties proteolysis in mammalian cells to active enhancers and to promoters of specific gene families. Nuclear-encoded mitochondrial genes in particular correlate with protein elimination, which positively affects their transcription. We show that the nuclear receptor corepressor NCoR1 is a key target of proteolysis and physically interacts with the transcription factor CREB. Proteasome inhibition stabilizes NCoR1 in a site-specific manner and restrains mitochondrial activity by repressing CREB-sensitive genes. In conclusion, this functional map of nuclear proteolysis links chromatin architecture with local protein stability and identifies proteolytic derepression as highly dynamic in regulating the transcription of genes involved in energy metabolism.
Assuntos
Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Regulação da Expressão Gênica , Correpressor 1 de Receptor Nuclear/metabolismo , Proteólise , Elementos Reguladores de Transcrição , Animais , Estudo de Associação Genômica Ampla , Humanos , Camundongos , Mitocôndrias/metabolismo , UbiquitinaçãoRESUMO
Cells acquire their fate in vivo in the context of a complex microenvironmental "niche" comprised of heterologous cell types, signaling molecules, extracellular matrix, biophysical forces, and metabolic substrates. Now Calderón and Boehm report the "refunctionalization" of a defective thymic epithelial niche, offering insights into how signaling molecules may be hierarchically organized to direct differentiation outcomes.
RESUMO
BACKGROUND: The function of the thymus in human adults is unclear, and routine removal of the thymus is performed in a variety of surgical procedures. We hypothesized that the adult thymus is needed to sustain immune competence and overall health. METHODS: We evaluated the risk of death, cancer, and autoimmune disease among adult patients who had undergone thymectomy as compared with demographically matched controls who had undergone similar cardiothoracic surgery without thymectomy. T-cell production and plasma cytokine levels were also compared in a subgroup of patients. RESULTS: After exclusions, 1420 patients who had undergone thymectomy and 6021 controls were included in the study; 1146 of the patients who had undergone thymectomy had a matched control and were included in the primary cohort. At 5 years after surgery, all-cause mortality was higher in the thymectomy group than in the control group (8.1% vs. 2.8%; relative risk, 2.9; 95% confidence interval [CI], 1.7 to 4.8), as was the risk of cancer (7.4% vs. 3.7%; relative risk, 2.0; 95% CI, 1.3 to 3.2). Although the risk of autoimmune disease did not differ substantially between the groups in the overall primary cohort (relative risk, 1.1; 95% CI, 0.8 to 1.4), a difference was found when patients with preoperative infection, cancer, or autoimmune disease were excluded from the analysis (12.3% vs. 7.9%; relative risk, 1.5; 95% CI, 1.02 to 2.2). In an analysis involving all patients with more than 5 years of follow-up (with or without a matched control), all-cause mortality was higher in the thymectomy group than in the general U.S. population (9.0% vs. 5.2%), as was mortality due to cancer (2.3% vs. 1.5%). In the subgroup of patients in whom T-cell production and plasma cytokine levels were measured (22 in the thymectomy group and 19 in the control group; mean follow-up, 14.2 postoperative years), those who had undergone thymectomy had less new production of CD4+ and CD8+ lymphocytes than controls (mean CD4+ signal joint T-cell receptor excision circle [sjTREC] count, 1451 vs. 526 per microgram of DNA [P = 0.009]; mean CD8+ sjTREC count, 1466 vs. 447 per microgram of DNA [P<0.001]) and higher levels of proinflammatory cytokines in the blood. CONCLUSIONS: In this study, all-cause mortality and the risk of cancer were higher among patients who had undergone thymectomy than among controls. Thymectomy also appeared be associated with an increased risk of autoimmune disease when patients with preoperative infection, cancer, or autoimmune disease were excluded from the analysis. (Funded by the Tracey and Craig A. Huff Harvard Stem Cell Institute Research Support Fund and others.).
Assuntos
Doenças Autoimunes , Timectomia , Humanos , Adulto , Timectomia/efeitos adversos , Timo , Linfócitos T CD8-Positivos , Citocinas , Doenças Autoimunes/complicaçõesRESUMO
ABSTRACT: Fanconi anemia (FA) is an inherited DNA repair disorder characterized by bone marrow (BM) failure, developmental abnormalities, myelodysplasia, leukemia, and solid tumor predisposition. Allogeneic hematopoietic stem cell transplantation (allo-HSCT), a mainstay treatment, is limited by conditioning regimen-related toxicity and graft-versus-host disease (GVHD). Antibody-drug conjugates (ADCs) targeting hematopoietic stem cells (HSCs) can open marrow niches permitting donor stem cell alloengraftment. Here, we report that single dose anti-mouse CD45-targeted ADC (CD45-ADC) facilitated stable, multilineage chimerism in 3 distinct FA mouse models representing 90% of FA complementation groups. CD45-ADC profoundly depleted host stem cell enriched Lineage-Sca1+cKit+ cells within 48 hours. Fanca-/- recipients of minor-mismatched BM and single dose CD45-ADC had peripheral blood (PB) mean donor chimerism >90%; donor HSCs alloengraftment was verified in secondary recipients. In Fancc-/- and Fancg-/- recipients of fully allogeneic grafts, PB mean donor chimerism was 60% to 80% and 70% to 80%, respectively. The mean percent donor chimerism in BM and spleen mirrored PB results. CD45-ADC-conditioned mice did not have clinical toxicity. A transient <2.5-fold increase in hepatocellular enzymes and mild-to-moderate histopathological changes were seen. Under GVHD allo-HSCT conditions, wild-type and Fanca-/- recipients of CD45-ADC had markedly reduced GVHD lethality compared with lethal irradiation. Moreover, single dose anti-human CD45-ADC given to rhesus macaque nonhuman primates on days -6 or -10 was at least as myeloablative as lethal irradiation. These data suggest that CD45-ADC can potently promote donor alloengraftment and hematopoiesis without significant toxicity or severe GVHD, as seen with lethal irradiation, providing strong support for clinical trial considerations in highly vulnerable patients with FA.
Assuntos
Anemia de Fanconi , Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Imunoconjugados , Antígenos Comuns de Leucócito , Animais , Anemia de Fanconi/terapia , Camundongos , Doença Enxerto-Hospedeiro/patologia , Imunoconjugados/farmacologia , Imunoconjugados/uso terapêutico , Condicionamento Pré-Transplante/métodos , Transplante Homólogo , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
AKT activation is associated with many malignancies, where AKT acts, in part, by inhibiting FOXO tumor suppressors. We show a converse role for AKT/FOXOs in acute myeloid leukemia (AML). Rather than decreased FOXO activity, we observed that FOXOs are active in â¼40% of AML patient samples regardless of genetic subtype. We also observe this activity in human MLL-AF9 leukemia allele-induced AML in mice, where either activation of Akt or compound deletion of FoxO1/3/4 reduced leukemic cell growth, with the latter markedly diminishing leukemia-initiating cell (LIC) function in vivo and improving animal survival. FOXO inhibition resulted in myeloid maturation and subsequent AML cell death. FOXO activation inversely correlated with JNK/c-JUN signaling, and leukemic cells resistant to FOXO inhibition responded to JNK inhibition. These data reveal a molecular role for AKT/FOXO and JNK/c-JUN in maintaining a differentiation blockade that can be targeted to inhibit leukemias with a range of genetic lesions.
Assuntos
Fatores de Transcrição Forkhead/metabolismo , Leucemia Mieloide/metabolismo , Leucemia Mieloide/patologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Animais , Antígenos CD34/metabolismo , Apoptose , Células da Medula Óssea/citologia , Células da Medula Óssea/metabolismo , Diferenciação Celular , Linhagem Celular Tumoral , Células Cultivadas , Modelos Animais de Doenças , Proteína Forkhead Box O3 , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Camundongos , Células-Tronco Neoplásicas/citologia , Células-Tronco Neoplásicas/metabolismoRESUMO
The avascular nature of cartilage makes it a unique tissue1-4, but whether and how the absence of nutrient supply regulates chondrogenesis remain unknown. Here we show that obstruction of vascular invasion during bone healing favours chondrogenic over osteogenic differentiation of skeletal progenitor cells. Unexpectedly, this process is driven by a decreased availability of extracellular lipids. When lipids are scarce, skeletal progenitors activate forkhead box O (FOXO) transcription factors, which bind to the Sox9 promoter and increase its expression. Besides initiating chondrogenesis, SOX9 acts as a regulator of cellular metabolism by suppressing oxidation of fatty acids, and thus adapts the cells to an avascular life. Our results define lipid scarcity as an important determinant of chondrogenic commitment, reveal a role for FOXO transcription factors during lipid starvation, and identify SOX9 as a critical metabolic mediator. These data highlight the importance of the nutritional microenvironment in the specification of skeletal cell fate.