RESUMO
Cancer cells frequently alter their lipids to grow and adapt to their environment1-3. Despite the critical functions of lipid metabolism in membrane physiology, signalling and energy production, how specific lipids contribute to tumorigenesis remains incompletely understood. Here, using functional genomics and lipidomic approaches, we identified de novo sphingolipid synthesis as an essential pathway for cancer immune evasion. Synthesis of sphingolipids is surprisingly dispensable for cancer cell proliferation in culture or in immunodeficient mice but required for tumour growth in multiple syngeneic models. Blocking sphingolipid production in cancer cells enhances the anti-proliferative effects of natural killer and CD8+ T cells partly via interferon-γ (IFNγ) signalling. Mechanistically, depletion of glycosphingolipids increases surface levels of IFNγ receptor subunit 1 (IFNGR1), which mediates IFNγ-induced growth arrest and pro-inflammatory signalling. Finally, pharmacological inhibition of glycosphingolipid synthesis synergizes with checkpoint blockade therapy to enhance anti-tumour immune response. Altogether, our work identifies glycosphingolipids as necessary and limiting metabolites for cancer immune evasion.
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Immune cells rely on transient physical interactions with other immune and non-immune populations to regulate their function1. To study these 'kiss-and-run' interactions directly in vivo, we previously developed LIPSTIC (labelling immune partnerships by SorTagging intercellular contacts)2, an approach that uses enzymatic transfer of a labelled substrate between the molecular partners CD40L and CD40 to label interacting cells. Reliance on this pathway limited the use of LIPSTIC to measuring interactions between CD4+ T helper cells and antigen-presenting cells, however. Here we report the development of a universal version of LIPSTIC (uLIPSTIC), which can record physical interactions both among immune cells and between immune and non-immune populations irrespective of the receptors and ligands involved. We show that uLIPSTIC can be used, among other things, to monitor the priming of CD8+ T cells by dendritic cells, reveal the steady-state cellular partners of regulatory T cells and identify germinal centre-resident T follicular helper cells on the basis of their ability to interact cognately with germinal centre B cells. By coupling uLIPSTIC with single-cell transcriptomics, we build a catalogue of the immune populations that physically interact with intestinal epithelial cells at the steady state and profile the evolution of the interactome of lymphocytic choriomeningitis virus-specific CD8+ T cells in multiple organs following systemic infection. Thus, uLIPSTIC provides a broadly useful technology for measuring and understanding cell-cell interactions across multiple biological systems.
Assuntos
Linfócitos B , Linfócitos T CD8-Positivos , Comunicação Celular , Células Dendríticas , Células Epiteliais , Células T Auxiliares Foliculares , Linfócitos T Reguladores , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Comunicação Celular/imunologia , Células Dendríticas/citologia , Células Dendríticas/imunologia , Ligantes , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/imunologia , Células T Auxiliares Foliculares/citologia , Células T Auxiliares Foliculares/imunologia , Linfócitos B/citologia , Linfócitos B/imunologia , Centro Germinativo/citologia , Análise da Expressão Gênica de Célula Única , Células Epiteliais/citologia , Células Epiteliais/imunologia , Mucosa Intestinal/citologia , Mucosa Intestinal/imunologia , Vírus da Coriomeningite Linfocítica/imunologia , Coriomeningite Linfocítica/imunologia , Coriomeningite Linfocítica/virologia , Especificidade de ÓrgãosRESUMO
Interactions between different cell types are key for immune function. Traditionally, interactions have been investigated in vivo by intravital two-photon microscopy, but the molecular characterization of the cells participating in a specific interaction is limited by the inability to retrieve the cells for downstream analysis. We recently developed an approach to label cells undergoing specific interactions in vivo, which we called LIPSTIC (Labeling Immune Partnership by Sortagging Intercellular Contacts). Here, we provide detailed instructions on how to track CD40-CD40L interactions between dendritic cells (DCs) and CD4+ T cells using genetically engineered LIPSTIC mice. This protocol requires expertise in animal experimentation and multicolor flow cytometry. Once mouse crossing has been achieved, it takes 3 days or more to complete, depending on the kinetics of the interactions that the researcher wishes to investigate.
Assuntos
Ligante de CD40 , Linfócitos T , Camundongos , Animais , Linfócitos T/metabolismo , Ligante de CD40/metabolismo , Antígenos CD40 , Células Dendríticas , Linfócitos T CD4-PositivosRESUMO
Pancreatic ductal adenocarcinoma (PDAC) cells require substantial metabolic rewiring to overcome nutrient limitations and immune surveillance. However, the metabolic pathways necessary for pancreatic tumor growth in vivo are poorly understood. To address this, we performed metabolism-focused CRISPR screens in PDAC cells grown in culture or engrafted in immunocompetent mice. While most metabolic gene essentialities are unexpectedly similar under these conditions, a small fraction of metabolic genes are differentially required for tumor progression. Among these, loss of heme synthesis reduces tumor growth due to a limiting role of heme in vivo, an effect independent of tissue origin or immune system. Our screens also identify autophagy as a metabolic requirement for pancreatic tumor immune evasion. Mechanistically, autophagy protects cancer cells from CD8+ T cell killing through TNFα-induced cell death in vitro. Altogether, this resource provides metabolic dependencies arising from microenvironmental limitations and the immune system, nominating potential anti-cancer targets.
Assuntos
Sistemas CRISPR-Cas/genética , Carcinoma Ductal Pancreático/metabolismo , Neoplasias Pancreáticas/metabolismo , Animais , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Proliferação de Células , Sobrevivência Celular , Células Cultivadas , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos Transgênicos , Neoplasias Experimentais/genética , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologiaRESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
Checkpoint blockade therapies have improved cancer treatment, but such immunotherapy regimens fail in a large subset of patients. Conventional type 1 dendritic cells (DC1s) control the response to checkpoint blockade in preclinical models and are associated with better overall survival in patients with cancer, reflecting the specialized ability of these cells to prime the responses of CD8+ T cells1-3. Paradoxically, however, DC1s can be found in tumours that resist checkpoint blockade, suggesting that the functions of these cells may be altered in some lesions. Here, using single-cell RNA sequencing in human and mouse non-small-cell lung cancers, we identify a cluster of dendritic cells (DCs) that we name 'mature DCs enriched in immunoregulatory molecules' (mregDCs), owing to their coexpression of immunoregulatory genes (Cd274, Pdcd1lg2 and Cd200) and maturation genes (Cd40, Ccr7 and Il12b). We find that the mregDC program is expressed by canonical DC1s and DC2s upon uptake of tumour antigens. We further find that upregulation of the programmed death ligand 1 protein-a key checkpoint molecule-in mregDCs is induced by the receptor tyrosine kinase AXL, while upregulation of interleukin (IL)-12 depends strictly on interferon-γ and is controlled negatively by IL-4 signalling. Blocking IL-4 enhances IL-12 production by tumour-antigen-bearing mregDC1s, expands the pool of tumour-infiltrating effector T cells and reduces tumour burden. We have therefore uncovered a regulatory module associated with tumour-antigen uptake that reduces DC1 functionality in human and mouse cancers.
Assuntos
Células Dendríticas/imunologia , Células Dendríticas/patologia , Neoplasias Pulmonares/imunologia , Animais , Antígenos de Neoplasias/imunologia , Antígeno B7-H1/imunologia , Antígeno B7-H1/metabolismo , Linfócitos T CD8-Positivos/imunologia , Carcinoma Pulmonar de Células não Pequenas/imunologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/terapia , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/metabolismo , Humanos , Imunoterapia , Interferon gama/imunologia , Interleucina-12/imunologia , Interleucina-4/antagonistas & inibidores , Interleucina-4/imunologia , Interleucina-4/metabolismo , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/terapia , Masculino , Camundongos , Carga Tumoral/efeitos dos fármacos , Carga Tumoral/imunologiaRESUMO
Atherosclerosis is driven by multifaceted contributions of the immune system within the circulation and at vascular focal sites. However, specific characteristics of dysregulated immune cells within atherosclerotic lesions that lead to clinical events such as ischemic stroke or myocardial infarction are poorly understood. Here, using single-cell proteomic and transcriptomic analyses, we uncovered distinct features of both T cells and macrophages in carotid artery plaques of patients with clinically symptomatic disease (recent stroke or transient ischemic attack) compared to asymptomatic disease (no recent stroke). Plaques from symptomatic patients were characterized by a distinct subset of CD4+ T cells and by T cells that were activated and differentiated. Moreover, some T cell subsets in these plaques presented markers of T cell exhaustion. Additionally, macrophages from these plaques contained alternatively activated phenotypes, including subsets associated with plaque vulnerability. In plaques from asymptomatic patients, T cells and macrophages were activated and displayed evidence of interleukin-1ß signaling. The identification of specific features of innate and adaptive immune cells in plaques that are associated with cerebrovascular events may enable the design of more precisely tailored cardiovascular immunotherapies.
Assuntos
Aterosclerose/imunologia , Interleucina-1beta/genética , Placa Aterosclerótica/metabolismo , Análise de Célula Única , Imunidade Adaptativa/genética , Idoso , Aterosclerose/genética , Aterosclerose/patologia , Diferenciação Celular/genética , Endarterectomia das Carótidas , Feminino , Humanos , Imunidade Inata/genética , Interleucina-1beta/imunologia , Leucócitos Mononucleares , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Placa Aterosclerótica/imunologia , Placa Aterosclerótica/patologia , Proteoma/genética , Proteoma/imunologia , Transdução de Sinais/genética , Linfócitos T/imunologia , Linfócitos T/metabolismo , Transcriptoma/genética , Transcriptoma/imunologiaRESUMO
Interactions between different cell types are essential for multiple biological processes, including immunity, embryonic development and neuronal signalling. Although the dynamics of cell-cell interactions can be monitored in vivo by intravital microscopy, this approach does not provide any information on the receptors and ligands involved or enable the isolation of interacting cells for downstream analysis. Here we describe a complementary approach that uses bacterial sortase A-mediated cell labelling across synapses of immune cells to identify receptor-ligand interactions between cells in living mice, by generating a signal that can subsequently be detected ex vivo by flow cytometry. We call this approach for the labelling of 'kiss-and-run' interactions between immune cells 'Labelling Immune Partnerships by SorTagging Intercellular Contacts' (LIPSTIC). Using LIPSTIC, we show that interactions between dendritic cells and CD4+ T cells during T-cell priming in vivo occur in two distinct modalities: an early, cognate stage, during which CD40-CD40L interactions occur specifically between T cells and antigen-loaded dendritic cells; and a later, non-cognate stage during which these interactions no longer require prior engagement of the T-cell receptor. Therefore, LIPSTIC enables the direct measurement of dynamic cell-cell interactions both in vitro and in vivo. Given its flexibility for use with different receptor-ligand pairs and a range of detectable labels, we expect that this approach will be of use to any field of biology requiring quantification of intercellular communication.
Assuntos
Comunicação Celular , Células Dendríticas/citologia , Células Dendríticas/imunologia , Sinapses Imunológicas/metabolismo , Coloração e Rotulagem/métodos , Linfócitos T/citologia , Linfócitos T/imunologia , Aminoaciltransferases/metabolismo , Animais , Proteínas de Bactérias/metabolismo , Contagem de Linfócito CD4 , Antígenos CD40/imunologia , Antígenos CD40/metabolismo , Ligante de CD40/imunologia , Ligante de CD40/metabolismo , Cisteína Endopeptidases/metabolismo , Feminino , Citometria de Fluxo , Células HEK293 , Humanos , Sinapses Imunológicas/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Antígenos de Linfócitos T/metabolismoRESUMO
While conventional pathogenic protists have been extensively studied, there is an underappreciated constitutive protist microbiota that is an integral part of the vertebrate microbiome. The impact of these species on the host and their potential contributions to mucosal immune homeostasis remain poorly studied. Here, we show that the protozoan Tritrichomonas musculis activates the host epithelial inflammasome to induce IL-18 release. Epithelial-derived IL-18 promotes dendritic cell-driven Th1 and Th17 immunity and confers dramatic protection from mucosal bacterial infections. Along with its role as a "protistic" antibiotic, colonization with T. musculis exacerbates the development of T-cell-driven colitis and sporadic colorectal tumors. Our findings demonstrate a novel mutualistic host-protozoan interaction that increases mucosal host defenses at the cost of an increased risk of inflammatory disease.
Assuntos
Colite/imunologia , Colite/parasitologia , Interações Hospedeiro-Parasita , Inflamassomos/imunologia , Mucosa Intestinal/parasitologia , Microbiota/imunologia , Tricomoníase/imunologia , Trichomonas/imunologia , Animais , Colite/microbiologia , Dientamoeba/imunologia , Imunidade nas Mucosas , Interleucina-18/imunologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Infecções por Salmonella/imunologia , Salmonella typhimurium/imunologia , Simbiose , Células Th1/imunologia , Células Th17/imunologiaRESUMO
The intestinal microbiota and tissue-resident myeloid cells promote immune responses that maintain intestinal homeostasis in the host. However, the cellular cues that translate microbial signals into intestinal homeostasis remain unclear. Here, we show that deficient granulocyte-macrophage colony-stimulating factor (GM-CSF) production altered mononuclear phagocyte effector functions and led to reduced regulatory T cell (T(reg)) numbers and impaired oral tolerance. We observed that RORγt(+) innate lymphoid cells (ILCs) are the primary source of GM-CSF in the gut and that ILC-driven GM-CSF production was dependent on the ability of macrophages to sense microbial signals and produce interleukin-1ß. Our findings reveal that commensal microbes promote a crosstalk between innate myeloid and lymphoid cells that leads to immune homeostasis in the intestine.
Assuntos
Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Tolerância Imunológica , Intestinos/imunologia , Intestinos/microbiologia , Macrófagos/imunologia , Macrófagos/microbiologia , Microbiota/imunologia , Animais , Antígenos/imunologia , Ingestão de Alimentos , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Homeostase , Imunidade Inata , Interleucina-1beta/imunologia , Camundongos , Camundongos Mutantes , Boca/imunologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Linfócitos T Reguladores/imunologiaRESUMO
Innate lymphoid cells (ILCs) regulate stromal cells, epithelial cells and cells of the immune system, but their effect on B cells remains unclear. Here we identified RORγt(+) ILCs near the marginal zone (MZ), a splenic compartment that contains innate-like B cells highly responsive to circulating T cell-independent (TI) antigens. Splenic ILCs established bidirectional crosstalk with MAdCAM-1(+) marginal reticular cells by providing tumor-necrosis factor (TNF) and lymphotoxin, and they stimulated MZ B cells via B cell-activation factor (BAFF), the ligand of the costimulatory receptor CD40 (CD40L) and the Notch ligand Delta-like 1 (DLL1). Splenic ILCs further helped MZ B cells and their plasma-cell progeny by coopting neutrophils through release of the cytokine GM-CSF. Consequently, depletion of ILCs impaired both pre- and post-immune TI antibody responses. Thus, ILCs integrate stromal and myeloid signals to orchestrate innate-like antibody production at the interface between the immune system and circulatory system.
Assuntos
Formação de Anticorpos , Linfócitos B/imunologia , Linfócitos/imunologia , Plasmócitos/imunologia , Baço/imunologia , Animais , Anticorpos/sangue , Antígenos T-Independentes/imunologia , Proteínas Sanguíneas/imunologia , Moléculas de Adesão Celular , Comunicação Celular/imunologia , Diferenciação Celular , Células Cultivadas , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Humanos , Imunidade Inata , Imunoglobulinas/metabolismo , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Mucoproteínas/metabolismo , Neutrófilos/imunologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Picratos/imunologia , Transdução de Sinais/imunologia , Células Estromais/imunologiaRESUMO
Macrophages frequently infiltrate tumors and can enhance cancer growth, yet the origins of the macrophage response are not well understood. Here we address molecular mechanisms of macrophage production in a conditional mouse model of lung adenocarcinoma. We report that overproduction of the peptide hormone Angiotensin II (AngII) in tumor-bearing mice amplifies self-renewing hematopoietic stem cells (HSCs) and macrophage progenitors. The process occurred in the spleen but not the bone marrow, and was independent of hemodynamic changes. The effects of AngII required direct hormone ligation on HSCs, depended on S1P(1) signaling, and allowed the extramedullary tissue to supply new tumor-associated macrophages throughout cancer progression. Conversely, blocking AngII production prevented cancer-induced HSC and macrophage progenitor amplification and thus restrained the macrophage response at its source. These findings indicate that AngII acts upstream of a potent macrophage amplification program and that tumors can remotely exploit the hormone's pathway to stimulate cancer-promoting immunity.
Assuntos
Adenocarcinoma/metabolismo , Angiotensina II/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Neoplasias Pulmonares/metabolismo , Macrófagos/metabolismo , Baço/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/patologia , Adenocarcinoma de Pulmão , Angiotensina II/metabolismo , Animais , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Comunicação Celular , Movimento Celular , Proliferação de Células , Expressão Gênica , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Hematopoéticas/patologia , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Lisofosfolipídeos/metabolismo , Macrófagos/patologia , Camundongos , Camundongos Transgênicos , Transdução de Sinais , Esfingosina/análogos & derivados , Esfingosina/metabolismo , Baço/patologia , Carga TumoralRESUMO
Atherosclerosis and insulin resistance are major components of the cardiometabolic syndrome, a global health threat associated with a systemic inflammatory state. Notch signaling regulates tissue development and participates in innate and adaptive immunity in adults. The role of Notch signaling in cardiometabolic inflammation, however, remains obscure. We noted that a high-fat, high-cholesterol diet increased expression of the Notch ligand Delta-like 4 (Dll4) in atheromata and fat tissue in LDL-receptor-deficient mice. Blockade of Dll4-Notch signaling using neutralizing anti-Dll4 antibody attenuated the development of atherosclerosis, diminished plaque calcification, improved insulin resistance, and decreased fat accumulation. These changes were accompanied by decreased macrophage accumulation, diminished expression of monocyte chemoattractant protein-1 (MCP-1), and lower levels of nuclear factor-κB (NF-κB) activation. In vitro cell culture experiments revealed that Dll4-mediated Notch signaling increases MCP-1 expression via NF-κB, providing a possible mechanism for in vivo effects. Furthermore, Dll4 skewed macrophages toward a proinflammatory phenotype ("M1"). These results suggest that Dll4-Notch signaling plays a central role in the shared mechanism for the pathogenesis of cardiometabolic disorders.
Assuntos
Anticorpos Neutralizantes/farmacologia , Aterosclerose/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Síndrome Metabólica/metabolismo , Células 3T3-L1 , Proteínas Adaptadoras de Transdução de Sinal , Adipócitos/citologia , Adipócitos/metabolismo , Tecido Adiposo/metabolismo , Animais , Insuficiência da Valva Aórtica/imunologia , Insuficiência da Valva Aórtica/metabolismo , Aterosclerose/imunologia , Aterosclerose/terapia , Proteínas de Ligação ao Cálcio , Quimiocina CCL2/metabolismo , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Humanos , Imunidade Inata/fisiologia , Resistência à Insulina/fisiologia , Peptídeos e Proteínas de Sinalização Intercelular/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/imunologia , Macrófagos/imunologia , Macrófagos/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Síndrome Metabólica/imunologia , Síndrome Metabólica/terapia , Camundongos , Camundongos Obesos , Camundongos Transgênicos , Receptores de LDL/genética , Receptores Notch/metabolismo , Veia Safena/citologia , Transdução de Sinais/fisiologiaRESUMO
Tumor-associated macrophages (TAMs) and tumor-associated neutrophils (TANs) can control cancer growth and exist in almost all solid neoplasms. The cells are known to descend from immature monocytic and granulocytic cells, respectively, which are produced in the bone marrow. However, the spleen is also a recently identified reservoir of monocytes, which can play a significant role in the inflammatory response that follows acute injury. Here, we evaluated the role of the splenic reservoir in a genetic mouse model of lung adenocarcinoma driven by activation of oncogenic Kras and inactivation of p53. We found that high numbers of TAM and TAN precursors physically relocated from the spleen to the tumor stroma, and that recruitment of tumor-promoting spleen-derived TAMs required signaling of the chemokine receptor CCR2. Also, removal of the spleen, either before or after tumor initiation, reduced TAM and TAN responses significantly and delayed tumor growth. The mechanism by which the spleen was able to maintain its reservoir capacity throughout tumor progression involved, in part, local accumulation in the splenic red pulp of typically rare extramedullary hematopoietic stem and progenitor cells, notably granulocyte and macrophage progenitors, which produced CD11b(+) Ly-6C(hi) monocytic and CD11b(+) Ly-6G(hi) granulocytic cells locally. Splenic granulocyte and macrophage progenitors and their descendants were likewise identified in clinical specimens. The present study sheds light on the origins of TAMs and TANs, and positions the spleen as an important extramedullary site, which can continuously supply growing tumors with these cells.
Assuntos
Macrófagos/imunologia , Neoplasias/patologia , Neutrófilos/imunologia , Animais , Humanos , Camundongos , Neoplasias/imunologia , Baço/imunologia , Baço/patologiaRESUMO
Monocytes (Mo) and macrophages (MΦ) are emerging therapeutic targets in malignant, cardiovascular, and autoimmune disorders. Targeting of Mo/MΦ and their effector functions without compromising innate immunity's critical defense mechanisms first requires addressing gaps in knowledge about the life cycle of these cells. Here we studied the source, tissue kinetics, and clearance of Mo/MΦ in murine myocardial infarction, a model of acute inflammation after ischemic injury. We found that a) Mo tissue residence time was surprisingly short (20 h); b) Mo recruitment rates were consistently high even days after initiation of inflammation; c) the sustained need of newly made Mo was fostered by extramedullary monocytopoiesis in the spleen; d) splenic monocytopoiesis was regulated by IL-1ß; and e) the balance of cell recruitment and local death shifted during resolution of inflammation. Depending on the experimental approach, we measured a 24 h Mo/MΦ exit rate from infarct tissue between 5 and 13% of the tissue cell population. Exited cells were most numerous in the blood, liver, and spleen. Abrogation of extramedullary monocytopoiesis proved deleterious for infarct healing and accelerated the evolution of heart failure. We also detected rapid Mo kinetics in mice with stroke. These findings expand our knowledge of Mo/MΦ flux in acute inflammation and provide the groundwork for novel anti-inflammatory strategies for treating heart failure.
Assuntos
Hematopoese Extramedular , Macrófagos/fisiologia , Monócitos/citologia , Monócitos/fisiologia , Infarto do Miocárdio/fisiopatologia , Transferência Adotiva , Animais , Biomarcadores/metabolismo , Morte Celular/genética , Modelos Animais de Doenças , Feminino , Inflamação/imunologia , Inflamação/metabolismo , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Cinética , Macrófagos/citologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Biológicos , Células Mieloides/metabolismo , Infarto do Miocárdio/imunologia , Infarto do Miocárdio/patologia , Transdução de Sinais , Baço/fisiologia , Acidente Vascular Cerebral/imunologia , Acidente Vascular Cerebral/metabolismo , Cicatrização/fisiologiaRESUMO
Recognition and clearance of a bacterial infection are a fundamental properties of innate immunity. Here, we describe an effector B cell population that protects against microbial sepsis. Innate response activator (IRA) B cells are phenotypically and functionally distinct, develop and diverge from B1a B cells, depend on pattern-recognition receptors, and produce granulocyte-macrophage colony-stimulating factor. Specific deletion of IRA B cell activity impairs bacterial clearance, elicits a cytokine storm, and precipitates septic shock. These observations enrich our understanding of innate immunity, position IRA B cells as gatekeepers of bacterial infection, and identify new treatment avenues for infectious diseases.
Assuntos
Subpopulações de Linfócitos B/imunologia , Infecções por Escherichia coli/imunologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Imunidade Inata , Peritonite/imunologia , Sepse/imunologia , Animais , Subpopulações de Linfócitos B/metabolismo , Linhagem da Célula , Separação Celular , Feminino , Citometria de Fluxo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/imunologia , Imunoglobulina M/metabolismo , Imunofenotipagem , Integrina alfa4beta1/imunologia , Integrina alfa4beta1/metabolismo , Lipopolissacarídeos , Ativação Linfocitária , Antígeno-1 Associado à Função Linfocitária/imunologia , Antígeno-1 Associado à Função Linfocitária/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Parabiose , Choque Séptico/imunologia , Baço/imunologia , Receptor 4 Toll-Like/imunologiaRESUMO
BACKGROUND: Atherosclerotic lesions are believed to grow via the recruitment of bone marrow-derived monocytes. Among the known murine monocyte subsets, Ly-6C(high) monocytes are inflammatory, accumulate in lesions preferentially, and differentiate. Here, we hypothesized that the bone marrow outsources the production of Ly-6C(high) monocytes during atherosclerosis. METHODS AND RESULTS: Using murine models of atherosclerosis and fate-mapping approaches, we show that hematopoietic stem and progenitor cells progressively relocate from the bone marrow to the splenic red pulp, where they encounter granulocyte macrophage colony-stimulating factor and interleukin-3, clonally expand, and differentiate to Ly-6C(high) monocytes. Monocytes born in such extramedullary niches intravasate, circulate, and accumulate abundantly in atheromata. On lesional infiltration, Ly-6C(high) monocytes secrete inflammatory cytokines, reactive oxygen species, and proteases. Eventually, they ingest lipids and become foam cells. CONCLUSIONS: Our findings indicate that extramedullary sites supplement the hematopoietic function of the bone marrow by producing circulating inflammatory cells that infiltrate atherosclerotic lesions.
Assuntos
Antígenos Ly , Aterosclerose/patologia , Movimento Celular/imunologia , Hematopoese Extramedular/imunologia , Monócitos/patologia , Animais , Antígenos Ly/biossíntese , Aterosclerose/imunologia , Medula Óssea , Diferenciação Celular , Fator Estimulador de Colônias de Granulócitos e Macrófagos , Células-Tronco Hematopoéticas/patologia , Inflamação , Interleucina-3 , Camundongos , Monócitos/imunologiaRESUMO
A current paradigm states that monocytes circulate freely and patrol blood vessels but differentiate irreversibly into dendritic cells (DCs) or macrophages upon tissue entry. Here we show that bona fide undifferentiated monocytes reside in the spleen and outnumber their equivalents in circulation. The reservoir monocytes assemble in clusters in the cords of the subcapsular red pulp and are distinct from macrophages and DCs. In response to ischemic myocardial injury, splenic monocytes increase their motility, exit the spleen en masse, accumulate in injured tissue, and participate in wound healing. These observations uncover a role for the spleen as a site for storage and rapid deployment of monocytes and identify splenic monocytes as a resource that the body exploits to regulate inflammation.