RESUMEN
Tissue inflammation is a hallmark of tumour microenvironments. In the bone marrow, tumour-associated inflammation impacts normal niches for haematopoietic progenitor cells and mature immune cells and supports the outgrowth and survival of malignant cells residing in these niche compartments. This Review provides an overview of our current understanding of inflammatory changes in the bone marrow microenvironment of myeloid and lymphoid malignancies, using acute myeloid leukaemia and multiple myeloma as examples and highlights unique and shared features of inflammation in niches for progenitor cells and plasma cells. Importantly, inflammation exerts profoundly different effects on normal bone marrow niches in these malignancies, and we provide context for possible drivers of these divergent effects. We explore the role of tumour cells in inflammatory changes, as well as the role of cellular constituents of normal bone marrow niches, including myeloid cells and stromal cells. Integrating knowledge of disease-specific dynamics of malignancy-associated bone marrow inflammation will provide a necessary framework for future targeting of these processes to improve patient outcome.
Asunto(s)
Médula Ósea , Neoplasias Hematológicas , Inflamación , Microambiente Tumoral , Humanos , Inflamación/inmunología , Inflamación/patología , Médula Ósea/patología , Médula Ósea/inmunología , Neoplasias Hematológicas/inmunología , Neoplasias Hematológicas/patología , Microambiente Tumoral/inmunología , Animales , Células Madre Hematopoyéticas/inmunología , Células Madre Hematopoyéticas/patología , Mieloma Múltiple/inmunología , Mieloma Múltiple/patología , Nicho de Células Madre/inmunologíaRESUMEN
Cancer initiation is orchestrated by an interplay between tumor-initiating cells and their stromal/immune environment. Here, by adapted single-cell RNA sequencing, we decipher the predicted signaling between tissue-resident hematopoietic stem/progenitor cells (HSPC) and their neoplastic counterparts with their native niches in the human bone marrow. LEPR+ stromal cells are identified as central regulators of hematopoiesis through predicted interactions with all cells in the marrow. Inflammatory niche remodeling and the resulting deprivation of critical HSPC regulatory factors are predicted to repress high-output hematopoietic stem cell subsets in NPM1-mutated acute myeloid leukemia (AML), with relative resistance of clonal cells. Stromal gene signatures reflective of niche remodeling are associated with reduced relapse rates and favorable outcomes after chemotherapy across all genetic risk categories. Elucidation of the intercellular signaling defining human AML, thus, predicts that inflammatory remodeling of stem cell niches drives tissue repression and clonal selection but may pose a vulnerability for relapse-initiating cells in the context of chemotherapeutic treatment. SIGNIFICANCE: Tumor-promoting inflammation is considered an enabling characteristic of tumorigenesis, but mechanisms remain incompletely understood. By deciphering the predicted signaling between tissue-resident stem cells and their neoplastic counterparts with their environment, we identify inflammatory remodeling of stromal niches as a determinant of normal tissue repression and clinical outcomes in human AML. See related commentary by Lisi-Vega and Méndez-Ferrer, p. 349. This article is featured in Selected Articles from This Issue, p. 337.
Asunto(s)
Células Madre Hematopoyéticas , Leucemia Mieloide Aguda , Humanos , Médula Ósea , Leucemia Mieloide Aguda/genética , Hematopoyesis/genética , Células del EstromaRESUMEN
Mesenchymal stem cells (MSCs) play pivotal roles in tissue (re)generation. In the murine bone marrow, they are thought to reside within the Sca-1+ CD51+ bone marrow stromal cell population. Here, using scRNAseq, we aimed to delineate the cellularheterogeneity of this MSC-enriched population throughout development. At the fetal stage, the MSC population is relatively homogeneous with subsets predicted to contain stem/progenitor cells, based on transcriptional modeling and marker expression. These subsets decline in relative size throughout life, with postnatal emergence of specialized clusters, including hematopoietic stem/progenitor cell (HSPC) niches. In fetal development, these stromal HSPC niches are lacking, but subsets of endothelial cells express HSPC factors, suggesting that they may provide initial niches for emerging hematopoiesis. This cellular taxonomy of the MSC population upon development is anticipated to provide a resource aiding the prospective identification of cellular subsets and molecular mechanisms driving bone marrow (re)generation.
RESUMEN
RUNX1 familial platelet disorder (RUNX1-FPD) is a hematopoietic disorder caused by germline loss-of-function mutations in the RUNX1 gene and characterized by thrombocytopathy, thrombocytopenia, and an increased risk of developing hematologic malignancies, mostly of myeloid origin. Disease pathophysiology has remained incompletely understood, in part because of a shortage of in vivo models recapitulating the germline RUNX1 loss of function found in humans, precluding the study of potential contributions of non-hematopoietic cells to disease pathogenesis. Here, we studied mice harboring a germline hypomorphic mutation of one Runx1 allele with a loss-of-function mutation in the other Runx1 allele (Runx1 L148A/- mice), which display many hematologic characteristics found in human RUNX1-FPD patients. Runx1 L148A/- mice displayed robust and pronounced thrombocytopenia and myeloid-biased hematopoiesis, associated with an HSC intrinsic reconstitution defect in lymphopoiesis and expansion of myeloid progenitor cell pools. We demonstrate that specific deletion of Runx1 from bone marrow stromal cells in Prrx1-cre;Runx1 fl/fl mice did not recapitulate these abnormalities, indicating that the hematopoietic abnormalities are intrinsic to the hematopoietic lineage, and arguing against a driving role of the bone marrow microenvironment. In conclusion, we report a RUNX1-FPD mouse model faithfully recapitulating key characteristics of human disease. Findings do not support a driving role of ancillary, non-hematopoietic cells in the disruption of hematopoiesis under homeostatic conditions.
RESUMEN
We describe a patient with congenital neutropenia (CN) with a homozygous germline mutation in the colony-stimulating factor 3 receptor gene (CSF3R). The patient's bone marrow shows lagging neutrophil development with subtle left shift and unresponsiveness to CSF3 in in vitro colony assays. This patient illustrates that the di-proline hinge motif in the extracellular cytokine receptor homology domain of CSF3R is critical for adequate neutrophil production, but dispensable for in vivo terminal neutrophil maturation. This report underscores that CN patients with inherited CSF3R mutations should be marked as a separate clinical entity, characterized by a failure to respond to CSF3.
Asunto(s)
Neutropenia , Receptores del Factor Estimulante de Colonias , Humanos , Receptores del Factor Estimulante de Colonias/genética , Mutación , Receptores de Citocinas/genética , Factor Estimulante de Colonias de Granulocitos , Neutropenia/genéticaRESUMEN
Innate and adaptive immune cells participate in the homeostatic regulation of hematopoietic stem cells (HSCs). Here, we interrogate the contribution of myeloid cells, the most abundant cell type in the mammalian bone marrow, in a clinically relevant mouse model of neutropenia. Long-term genetic depletion of neutrophils and eosinophils results in activation of multipotent progenitors but preservation of HSCs. Depletion of myeloid cells abrogates HSC expansion, loss of serial repopulation and lymphoid reconstitution capacity and remodeling of HSC niches, features previously associated with hematopoietic aging. This is associated with mitigation of interferon signaling in both HSCs and their niches via reduction of NK cell number and activation. These data implicate myeloid cells in the functional decline of hematopoiesis, associated with activation of interferon signaling via a putative neutrophil-NK cell axis. Innate immunity may thus come at the cost of system deterioration through enhanced chronic inflammatory signaling to stem cells and their niches.
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Hematopoyesis , Células Madre Hematopoyéticas , Ratones , Animales , Células Madre Hematopoyéticas/metabolismo , Células Mieloides , Médula Ósea/fisiología , Interferones/metabolismo , Diferenciación Celular , MamíferosRESUMEN
Familial platelet disorder with associated myeloid malignancies (RUNX1-familial platelet disorder [RUNX1-FPD]) is caused by heterozygous pathogenic germline variants of RUNX1. In the present study, we evaluate the applicability of transactivation assays to investigate RUNX1 variants in different regions of the protein. We studied 11 variants to independently validate transactivation assays supporting variant classification following the ClinGen Myeloid Malignancies Variant Curation Expert Panel guidelines. Variant classification is key for the translation of genetic findings. We showed that new assays need to be developed to assess C-terminal RUNX1 variants. Two variants of uncertain significance (VUS) were reclassified to likely pathogenic. Additionally, our analyses supported the (likely) pathogenic classification of 2 other variants. We demonstrated functionality of 4 VUS, but reclassification to (likely) benign was challenging and suggested the need for reevaluating current classification guidelines. Finally, clinical utility of our assays was illustrated in the context of 7 families. Our data confirmed RUNX1-FPD suspicion in 3 families with RUNX1-FPD-specific family history, whereas for 3 variants identified in RUNX1-FPD-nonspecific families, no functional defect was detected. Applying functional assays to support RUNX1 variant classification can be essential for adequate care of index patients and their relatives at risk. It facilitates translation of genetic data into personalized medicine.
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Trastornos de las Plaquetas Sanguíneas , Leucemia Mieloide Aguda , Trastornos de las Plaquetas Sanguíneas/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/metabolismo , Células Germinativas , Humanos , Leucemia Mieloide Aguda/genética , Activación TranscripcionalRESUMEN
For many cancers, adolescents and young adults (AYAs) have a poorer prognosis than pediatric patients. Our study evaluates survival outcomes of children (0-17 years) and AYAs (18-39 years) diagnosed with acute myeloid leukemia (AML) in the Netherlands between 1990 and 2015 (N = 2058) utilizing the population-based Netherlands Cancer Registry, which includes information on therapy and site of primary treatment. Five- and 10-year relative (disease-specific) survival were estimated for all patients, children and AYAs. Multivariable analyses were performed using generalized linear models (excess mortality) and logistic regression (early mortality). AYAs with AML had a substantially lower 5- and 10-year relative survival than children (5-year: 43% vs 58%; 10-year: 37% vs 51%). The gap in 5-year relative survival was largest (nearly 20 percent-points) in 2010 to 2015, despite survival improvements over time across all ages. The multivariable-adjusted excess risk of dying was 60% higher in AYAs (95% CI: 37%-86%). Early mortality (death within 30 days of diagnosis) declined over time, and did not differ between children and AYAs. In conclusion, AYAs diagnosed with AML in the Netherlands had a worse prognosis than pediatric patients. The survival gap seemed most pronounced in recent years, suggesting that improvements in care resulting in better outcome for children have not led to equal benefits for AYAs.
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Leucemia Mieloide Aguda/mortalidad , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Leucemia Promielocítica Aguda/mortalidad , Modelos Lineales , Modelos Logísticos , Masculino , Países Bajos/epidemiología , Adulto JovenAsunto(s)
Trastornos de las Plaquetas Sanguíneas/patología , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Subunidad beta del Factor de Unión al Sitio Principal/metabolismo , Leucemia Eritroblástica Aguda/patología , Leucemia Mieloide Aguda/patología , Mutación , Trastornos Mieloproliferativos/patología , Bioensayo , Trastornos de las Plaquetas Sanguíneas/genética , Trastornos de las Plaquetas Sanguíneas/metabolismo , Subunidad alfa 2 del Factor de Unión al Sitio Principal/clasificación , Subunidad alfa 2 del Factor de Unión al Sitio Principal/metabolismo , Subunidad beta del Factor de Unión al Sitio Principal/genética , Predisposición Genética a la Enfermedad , Humanos , Leucemia Eritroblástica Aguda/genética , Leucemia Eritroblástica Aguda/metabolismo , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Trastornos Mieloproliferativos/genética , Trastornos Mieloproliferativos/metabolismo , Fosforilación , Activación TranscripcionalRESUMEN
Human bone marrow stromal cells (BMSC) are key elements of the hematopoietic environment and they play a central role in bone and bone marrow physiology. However, how key stromal cell functions are regulated is largely unknown. We analyzed the role of the immediate early response transcription factor EGR1 as key stromal cell regulator and found that EGR1 was highly expressed in prospectively-isolated primary BMSC, down-regulated upon culture, and low in non-colony-forming CD45neg stromal cells. Furthermore, EGR1 expression was lower in proliferative regenerating adult and fetal primary cells compared to adult steady-state BMSC. Overexpression of EGR1 in stromal cells induced potent hematopoietic stroma support as indicated by an increased production of transplantable CD34+CD90+ hematopoietic stem cells in expansion co-cultures. The improvement in bone marrow stroma support function was mediated by increased expression of hematopoietic supporting genes, such as VCAM1 and CCL28 Furthermore, EGR1 overexpression markedly decreased stromal cell proliferation whereas EGR1 knockdown caused the opposite effects. These findings thus show that EGR1 is a key stromal transcription factor with a dual role in regulating proliferation and hematopoietic stroma support function that is controlling a genetic program to co-ordinate the specific functions of BMSC in their different biological contexts.
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Células Madre Mesenquimatosas , Adulto , Antígenos CD34 , Células de la Médula Ósea , Proliferación Celular , Células Madre Hematopoyéticas , Humanos , Células del EstromaRESUMEN
The drivers of aging in the hematopoietic system remain incompletely understood. In this issue of Cell Stem Cell, Ho et al. (2019) report that functional switching of ß-adrenergic nerve signaling underlies remodeling of stem cell niches, driving age-associated alterations in hematopoiesis.
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Médula Ósea , Nicho de Células Madre , Hematopoyesis , Células Madre Hematopoyéticas , Células MieloidesRESUMEN
Myelodysplastic syndrome (MDS) is characterized by bone marrow failure and a strong propensity for leukemic evolution. Somatic mutations are critical early drivers of the disorder, but the factors enabling the emergence, selection, and subsequent leukemic evolution of these "leukemia-poised" clones remain incompletely understood. Emerging data point at the mesenchymal niche as a critical contributor to disease initiation and evolution. Disrupted inflammatory signaling from niche cells may facilitate the occurrence of somatic mutations, their selection, and subsequent clonal expansion. This review summarizes the current concepts about "niche-facilitated" bone marrow failure and leukemic evolution, their underlying molecular mechanisms, and clinical implications for future innovative therapeutic targeting of the niche in MDS.
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Células Madre Mesenquimatosas/citología , Mutación , Síndromes Mielodisplásicos/diagnóstico , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/terapia , Nicho de Células Madre , Progresión de la Enfermedad , Predisposición Genética a la Enfermedad , Células Madre Hematopoyéticas/citología , Humanos , Inflamación , Leucemia/sangre , Leucemia/etiología , Transducción de SeñalRESUMEN
RPS14, CSNK1A1, and miR-145 are universally co-deleted in the 5q- syndrome, but mouse models of each gene deficiency recapitulate only a subset of the composite clinical features. We analyzed the combinatorial effect of haploinsufficiency for Rps14, Csnk1a1, and miRNA-145, using mice with genetically engineered, conditional heterozygous inactivation of Rps14 and Csnk1a1 and stable knockdown of miR-145/miR-146a. Combined Rps14/Csnk1a1/miR-145/146a deficiency recapitulated the cardinal features of the 5q- syndrome, including (1) more severe anemia with faster kinetics than Rps14 haploinsufficiency alone and (2) pathognomonic megakaryocyte morphology. Macrophages, regulatory cells of erythropoiesis and the innate immune response, were significantly increased in Rps14/Csnk1a1/miR-145/146a deficient mice as well as in 5q- syndrome patient bone marrows and showed activation of the innate immune response, reflected by increased expression of S100A8, and decreased phagocytic function. We demonstrate that Rps14/Csnk1a1/miR-145 and miR-146a deficient macrophages alter the microenvironment and induce S100A8 expression in the mesenchymal stem cell niche. The increased S100A8 expression in the mesenchymal niche was confirmed in 5q- syndrome patients. These data indicate that intrinsic defects of the 5q- syndrome hematopoietic stem cell directly alter the surrounding microenvironment, which in turn affects hematopoiesis as an extrinsic mechanism.
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Anemia Macrocítica/inmunología , Anemia/inmunología , Caseína Quinasa Ialfa/fisiología , Haploinsuficiencia , MicroARNs/fisiología , Proteínas Ribosómicas/fisiología , Microambiente Tumoral/inmunología , Anemia/metabolismo , Anemia/patología , Anemia Macrocítica/metabolismo , Anemia Macrocítica/patología , Animales , Médula Ósea/inmunología , Médula Ósea/metabolismo , Médula Ósea/patología , Calgranulina A/genética , Calgranulina A/metabolismo , Deleción Cromosómica , Cromosomas Humanos Par 5/inmunología , Cromosomas Humanos Par 5/metabolismo , Eritropoyesis , Femenino , Células Madre Hematopoyéticas/inmunología , Células Madre Hematopoyéticas/metabolismo , Células Madre Hematopoyéticas/patología , Humanos , Megacariocitos/inmunología , Megacariocitos/metabolismo , Megacariocitos/patología , Ratones , Ratones Noqueados , Fenotipo , Células Tumorales CultivadasAsunto(s)
Biomarcadores de Tumor/metabolismo , Hematopoyesis , Mediadores de Inflamación/metabolismo , Células Madre Mesenquimatosas/patología , Síndromes Mielodisplásicos/patología , FN-kappa B/metabolismo , Biomarcadores de Tumor/genética , Estudios de Casos y Controles , Células Cultivadas , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Humanos , Células Madre Mesenquimatosas/inmunología , Células Madre Mesenquimatosas/metabolismo , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/inmunología , Síndromes Mielodisplásicos/metabolismo , FN-kappa B/genética , Pronóstico , Factores de RiesgoRESUMEN
Bone marrow (BM) mesenchymal stromal cells (MSCs) provide microenvironmental support to hematopoietic stem and progenitor cells (HSPCs). Culture-expanded MSCs are interesting candidates for cellular therapies due to their immunosuppressive and regenerative potential which can be further enhanced by pretreatment with interferon-gamma (IFN-γ). However, it remains unknown whether IFN-γ can also influence hematopoietic support by BM-MSCs. In this study, we elucidate the impact of IFN-γ on the hematopoietic support of BM-MSCs. We found that IFN-γ increases expression of interleukin (IL)-6 and stem cell factor by human BM-MSCs. IFN-γ-treated BM-MSCs drive HSPCs toward myeloid commitment in vitro, but impair subsequent differentiation of HSPC. Moreover, IFN-γ-ARE-Del mice with increased IFN-γ production specifically lose their BM-MSCs, which correlates with a loss of hematopoietic stem cells' quiescence. Although IFN-γ treatment enhances the immunomodulatory function of MSCs in a clinical setting, we conclude that IFN-γ negatively affects maintenance of BM-MSCs and their hematopoietic support in vitro and in vivo.