RESUMEN
A principal purpose of type 2 immunity was thought to be defense against large parasites, but it also functions in the restoration of homeostasis, such as toxin clearance following snake bites. In other cases, like allergy, the type 2 T helper (Th2) cytokines and cells present in the environment are detrimental and cause diseases. In recent years, the recognition of cell heterogeneity within Th2-associated cell populations has revealed specific functions of cells with a particular phenotype or gene signature. In addition, here we discuss the recent data regarding heterogeneity of type 2 immunity-related cells, as well as their newly identified role in a variety of processes ranging from involvement in respiratory viral infections [especially in the context of the recent COVID-19 (coronavirus disease 2019) pandemic] to control of cancer development or of metabolic homeostasis.
Asunto(s)
COVID-19 , Hipersensibilidad , Animales , Citocinas/metabolismo , Homeostasis , Humanos , Linfocitos T Colaboradores-Inductores/metabolismo , Células Th2RESUMEN
In many asthmatics, chronic airway inflammation is driven by IL-4-, IL-5-, and IL-13-producing Th2 cells or ILC2s. Type 2 cytokines promote hallmark features of the disease such as eosinophilia, mucus hypersecretion, bronchial hyperresponsiveness (BHR), IgE production, and susceptibility to exacerbations. However, only half the asthmatics have this "type 2-high" signature, and "type 2-low" asthma is more associated with obesity, presence of neutrophils, and unresponsiveness to corticosteroids, the mainstay asthma therapy. Here, we review the underlying immunological basis of various asthma endotypes by discussing results obtained from animal studies as well as results generated in clinical studies targeting specific immune pathways.
Asunto(s)
Asma/inmunología , Inmunidad Adaptativa , Células Epiteliales Alveolares/patología , Animales , Asma/fisiopatología , Asma/terapia , Asma/virología , Linfocitos B/inmunología , Terapia Biológica , Humanos , Inmunoglobulina E/inmunologíaRESUMEN
Lung dendritic cells (DCs) bridge innate and adaptive immunity, and depending on context, they also induce a Th1, Th2, or Th17 response to optimally clear infectious threats. Conversely, lung DCs can also mount maladaptive Th2 immune responses to harmless allergens and, in this way, contribute to immunopathology. It is now clear that the various aspects of DC biology can be understood only if we take into account the functional specializations of different DC subsets that are present in the lung in homeostasis or are attracted to the lung as part of the inflammatory response to inhaled noxious stimuli. Lung DCs are heavily influenced by the nearby epithelial cells, and a model is emerging whereby direct communication between DCs and epithelial cells determines the outcome of the pulmonary immune response. Here, we have approached DC biology from the perspective of viral infection and allergy to illustrate these emerging concepts.
Asunto(s)
Asma/inmunología , Células Dendríticas/inmunología , Gripe Humana/inmunología , Pulmón/inmunología , Inmunidad Adaptativa , Alérgenos/inmunología , Animales , Asma/prevención & control , Células Dendríticas/metabolismo , Humanos , Pulmón/patología , Pulmón/virología , Ratones , Neumonía/inmunología , Neumonía/patologíaRESUMEN
The activities, ontogeny, and mechanisms of lineage expansion of eosinophils are less well resolved than those of other immune cells, despite the use of biological therapies targeting the eosinophilia-promoting cytokine interleukin (IL)-5 or its receptor, IL-5Rα. We combined single-cell proteomics and transcriptomics and generated transgenic IL-5Rα reporter mice to revisit eosinophilopoiesis. We reconciled human and murine eosinophilopoiesis and provided extensive cell-surface immunophenotyping and transcriptomes at different stages along the continuum of eosinophil maturation. We used these resources to show that IL-5 promoted eosinophil-lineage expansion via transit amplification, while its deletion or neutralization did not compromise eosinophil maturation. Informed from our resources, we also showed that interferon response factor-8, considered an essential promoter of myelopoiesis, was not intrinsically required for eosinophilopoiesis. This work hence provides resources, methods, and insights for understanding eosinophil ontogeny, the effects of current precision therapeutics, and the regulation of eosinophil development and numbers in health and disease.
Asunto(s)
Linaje de la Célula , Eosinófilos , Interleucina-5 , Ratones Transgénicos , Proteómica , Análisis de la Célula Individual , Transcriptoma , Eosinófilos/inmunología , Eosinófilos/metabolismo , Animales , Interleucina-5/metabolismo , Interleucina-5/genética , Humanos , Ratones , Proteómica/métodos , Análisis de la Célula Individual/métodos , Diferenciación Celular/inmunología , Ratones Endogámicos C57BL , Perfilación de la Expresión Génica/métodos , Subunidad alfa del Receptor de Interleucina-5/metabolismo , Subunidad alfa del Receptor de Interleucina-5/genética , Mielopoyesis/genética , Factores Reguladores del Interferón/metabolismo , Factores Reguladores del Interferón/genética , Ratones NoqueadosRESUMEN
T cell receptor (TCR) signaling without CD28 can elicit primary effector T cells, but memory T cells generated during this process are anergic, failing to respond to secondary antigen exposure. We show that, upon T cell activation, CD28 transiently promotes expression of carnitine palmitoyltransferase 1a (Cpt1a), an enzyme that facilitates mitochondrial fatty acid oxidation (FAO), before the first cell division, coinciding with mitochondrial elongation and enhanced spare respiratory capacity (SRC). microRNA-33 (miR33), a target of thioredoxin-interacting protein (TXNIP), attenuates Cpt1a expression in the absence of CD28, resulting in cells that thereafter are metabolically compromised during reactivation or periods of increased bioenergetic demand. Early CD28-dependent mitochondrial engagement is needed for T cells to remodel cristae, develop SRC, and rapidly produce cytokines upon restimulation-cardinal features of protective memory T cells. Our data show that initial CD28 signals during T cell activation prime mitochondria with latent metabolic capacity that is essential for future T cell responses.
Asunto(s)
Antígenos CD28/metabolismo , Activación de Linfocitos , Mitocondrias/metabolismo , Linfocitos T/citología , Linfocitos T/inmunología , Animales , Carnitina O-Palmitoiltransferasa , Inhibidores Enzimáticos/farmacología , Compuestos Epoxi/farmacología , Humanos , Interleucina-15/inmunología , Ratones , Ratones Endogámicos C57BL , Receptores de Antígenos de Linfocitos T/metabolismo , Estrés Fisiológico , Linfocitos T/metabolismoAsunto(s)
Asma , Inmunoterapia Adoptiva , Receptores Quiméricos de Antígenos , Asma/inmunología , Humanos , Receptores Quiméricos de Antígenos/inmunología , Receptores Quiméricos de Antígenos/genética , Inmunoterapia Adoptiva/métodos , Animales , Linfocitos T/inmunología , Ratones , Receptores de Antígenos de Linfocitos T/inmunología , Receptores de Antígenos de Linfocitos T/metabolismoRESUMEN
Tissue-resident alveolar and interstitial macrophages and recruited macrophages are critical players in innate immunity and maintenance of lung homeostasis. Until recently, assessing the differential functional contributions of tissue-resident versus recruited macrophages has been challenging because they share overlapping cell surface markers, making it difficult to separate them using conventional methods. This review describes how scRNA-seq and spatial transcriptomics can separate these subpopulations and help unravel the complexity of macrophage biology in homeostasis and disease. First, we provide a guide to identifying and distinguishing lung macrophages from other mononuclear phagocytes in humans and mice. Second, we outline emerging concepts related to the development and function of the various lung macrophages in the alveolar, perivascular, and interstitial niches. Finally, we describe how different tissue states profoundly alter their functions, including acute and chronic lung disease, cancer, and aging.
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Enfermedades Pulmonares , Macrófagos Alveolares , Animales , Biología , Humanos , Pulmón , Macrófagos , RatonesRESUMEN
Childhood asthma is typically associated with a polarized Th2 response to inhaled allergens and is influenced by genetics. Yang et al. show that the asthma susceptibility gene DENND1B controls cytokine production in Th2 lymphocytes by controlling the rate of TCR internalization and routing to endosomes, providing a molecular basis for how DENND1B contributes to asthma pathogenesis.
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Asma/inmunología , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/metabolismo , Factores de Intercambio de Guanina Nucleótido/metabolismo , Receptores de Antígenos de Linfocitos T/metabolismo , Transducción de Señal , Células Th2/inmunología , Animales , Femenino , HumanosRESUMEN
In the version of this article initially published, the accession code for the RNA-seq data set deposited in the NCBI public repository Sequence Read Archive was missing from the 'Data availability' subsection of the Methods section. The accession code is SRP125477.
RESUMEN
While antibiotics are intended to specifically target bacteria, most are known to affect host cell physiology. In addition, some antibiotic classes are reported as immunosuppressive for reasons that remain unclear. Here, we show that Linezolid, a ribosomal-targeting antibiotic (RAbo), effectively blocked the course of a T cell-mediated autoimmune disease. Linezolid and other RAbos were strong inhibitors of T helper-17 cell effector function in vitro, showing that this effect was independent of their antibiotic activity. Perturbing mitochondrial translation in differentiating T cells, either with RAbos or through the inhibition of mitochondrial elongation factor G1 (mEF-G1) progressively compromised the integrity of the electron transport chain. Ultimately, this led to deficient oxidative phosphorylation, diminishing nicotinamide adenine dinucleotide concentrations and impairing cytokine production in differentiating T cells. In accordance, mice lacking mEF-G1 in T cells were protected from experimental autoimmune encephalomyelitis, demonstrating that this pathway is crucial in maintaining T cell function and pathogenicity.
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Antibacterianos/uso terapéutico , Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Linezolid/uso terapéutico , Mitocondrias/metabolismo , Péptidos Cíclicos/uso terapéutico , Ribosomas/metabolismo , Células Th17/fisiología , Animales , Autoinmunidad/efectos de los fármacos , Diferenciación Celular , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Mitocondrias/genética , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Terapia Molecular Dirigida , Esclerosis Múltiple/tratamiento farmacológico , NAD/metabolismo , Fosforilación Oxidativa , Factor G de Elongación Peptídica/genética , Factor G de Elongación Peptídica/metabolismoRESUMEN
The immunology of the hygiene hypothesis of allergy is complex and involves the loss of cellular and humoral immunoregulatory pathways as a result of the adoption of a Western lifestyle and the disappearance of chronic infectious diseases. The influence of diet and reduced microbiome diversity now forms the foundation of scientific thinking on how the allergy epidemic occurred, although clear mechanistic insights into the process in humans are still lacking. Here we propose that barrier epithelial cells are heavily influenced by environmental factors and by microbiome-derived danger signals and metabolites, and thus act as important rheostats for immunoregulation, particularly during early postnatal development. Preventive strategies based on this new knowledge could exploit the diversity of the microbial world and the way humans react to it, and possibly restore old symbiotic relationships that have been lost in recent times, without causing disease or requiring a return to an unhygienic life style.
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Epidermis/inmunología , Hipótesis de la Higiene , Hipersensibilidad/inmunología , Inmunidad Adaptativa , Factores de Edad , Alérgenos/inmunología , Animales , Epidermis/metabolismo , Epidermis/microbiología , Epitelio/inmunología , Epitelio/metabolismo , Epitelio/microbiología , Humanos , Estilo de Vida , MicrobiotaRESUMEN
The hygiene hypothesis postulates that the recent increase in allergic diseases such as asthma and hay fever observed in Western countries is linked to reduced exposure to childhood infections. Here we investigated how infection with a gammaherpesvirus affected the subsequent development of allergic asthma. We found that murid herpesvirus 4 (MuHV-4) inhibited the development of house dust mite (HDM)-induced experimental asthma by modulating lung innate immune cells. Specifically, infection with MuHV-4 caused the replacement of resident alveolar macrophages (AMs) by monocytes with regulatory functions. Monocyte-derived AMs blocked the ability of dendritic cells to trigger a HDM-specific response by the TH2 subset of helper T cells. Our results indicate that replacement of embryonic AMs by regulatory monocytes is a major mechanism underlying the long-term training of lung immunity after infection.
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Asma/terapia , Macrófagos Alveolares/inmunología , Monocitos/inmunología , Pyroglyphidae/inmunología , Rhadinovirus/inmunología , Células Th2/inmunología , Traslado Adoptivo , Animales , Asma/inmunología , Línea Celular , Cricetinae , Células Dendríticas/inmunología , Femenino , Infecciones por Herpesviridae/inmunología , Infecciones por Herpesviridae/virología , Macrófagos Alveolares/citología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Células Th2/trasplanteRESUMEN
Notch2 and B cell antigen receptor (BCR) signaling determine whether transitional B cells become marginal zone B (MZB) or follicular B (FoB) cells in the spleen, but it is unknown how these pathways are related. We generated Taok3-/- mice, lacking the serine/threonine kinase Taok3, and found cell-intrinsic defects in the development of MZB but not FoB cells. Type 1 transitional (T1) B cells required Taok3 to rapidly respond to ligation by the Notch ligand Delta-like 1. BCR ligation by endogenous or exogenous ligands induced the surface expression of the metalloproteinase ADAM10 on T1 B cells in a Taok3-dependent manner. T1 B cells expressing surface ADAM10 were committed to becoming MZB cells in vivo, whereas T1 B cells lacking expression of ADAM10 were not. Thus, during positive selection in the spleen, BCR signaling causes immature T1 B cells to become receptive to Notch ligands via Taok3-mediated surface expression of ADAM10.
Asunto(s)
Proteína ADAM10/metabolismo , Inmunidad Adaptativa , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Linfocitos B/fisiología , Diferenciación Celular , Linaje de la Célula , Centro Germinal/inmunología , Proteínas de la Membrana/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteína ADAM10/genética , Secretasas de la Proteína Precursora del Amiloide/genética , Animales , Células Cultivadas , Selección Clonal Mediada por Antígenos , Regulación de la Expresión Génica , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas de la Membrana/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas Serina-Treonina Quinasas/genética , Receptor Notch2/metabolismo , Receptores de Antígenos de Linfocitos B/metabolismo , Transducción de SeñalRESUMEN
The initial molecular events and the cell type(s) responsible for the development of fibrosis are unclear. Fukushima, Satoh, et al. find that increased expression of the nuclear exosome targeting complex component Rbm7 in lung epithelial cells promotes the degradation of the long non-coding RNA NEAT1, impairs DNA repair, and triggers apoptosis. Dying epithelial cells release chemokines that recruit atypical monocytes, which drive tissue fibrosis.
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Exosomas , ARN Largo no Codificante , Núcleo Celular , Fibrosis , Humanos , Proteínas de Unión al ARNRESUMEN
The phenotypic and functional dichotomy between IRF8+ type 1 and IRF4+ type 2 conventional dendritic cells (cDC1s and cDC2s, respectively) is well accepted; it is unknown how robust this dichotomy is under inflammatory conditions, when additionally monocyte-derived cells (MCs) become competent antigen-presenting cells (APCs). Using single-cell technologies in models of respiratory viral infection, we found that lung cDC2s acquired expression of the Fc receptor CD64 shared with MCs and of IRF8 shared with cDC1s. These inflammatory cDC2s (inf-cDC2s) were superior in inducing CD4+ T helper (Th) cell polarization while simultaneously presenting antigen to CD8+ T cells. When carefully separated from inf-cDC2s, MCs lacked APC function. Inf-cDC2s matured in response to cell-intrinsic Toll-like receptor and type 1 interferon receptor signaling, upregulated an IRF8-dependent maturation module, and acquired antigens via convalescent serum and Fc receptors. Because hybrid inf-cDC2s are easily confused with monocyte-derived cells, their existence could explain why APC functions have been attributed to MCs.
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Plasticidad de la Célula/inmunología , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Inmunidad , Macrófagos/inmunología , Macrófagos/metabolismo , Infecciones por Respirovirus/etiología , Presentación de Antígeno , Biomarcadores , Susceptibilidad a Enfermedades , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Redes Reguladoras de Genes , Inmunofenotipificación , Interferón Tipo I/metabolismo , Monocitos/inmunología , Monocitos/metabolismo , Especificidad de Órganos/inmunología , Receptores Fc/metabolismo , Infecciones por Respirovirus/metabolismo , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Factores de Transcripción , Virosis/genética , Virosis/inmunología , Virosis/metabolismo , Virosis/virologíaRESUMEN
Asthma is a chronic inflammatory airway disease associated with type 2 cytokines interleukin-4 (IL-4), IL-5, and IL-13, which promote airway eosinophilia, mucus overproduction, bronchial hyperresponsiveness (BHR), and immunogloubulin E (IgE) synthesis. However, only half of asthma patients exhibit signs of an exacerbated Type 2 response. "Type 2-low" asthma has different immune features: airway neutrophilia, obesity-related systemic inflammation, or in some cases, few signs of immune activation. Here, we review the cytokine networks driving asthma, placing these in cellular context and incorporating insights from cytokine-targeting therapies in the clinic. We discuss established and emerging paradigms in the context of the growing appreciation of disease heterogeneity and argue that the development of new and improved therapeutics will require understanding the diverse mechanisms underlying the spectrum of asthma pathologies.
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Asma/inmunología , Citocinas/inmunología , Inmunidad Adaptativa , Corticoesteroides/uso terapéutico , Alérgenos/inmunología , Animales , Antiasmáticos/uso terapéutico , Antiinflamatorios/uso terapéutico , Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/uso terapéutico , Asma/clasificación , Asma/tratamiento farmacológico , Asma/fisiopatología , Ensayos Clínicos como Asunto , Citocinas/antagonistas & inhibidores , Células Epiteliales/inmunología , Humanos , Inflamación/inmunología , Interferones/inmunología , Ratones , Ratones Noqueados , Modelos Inmunológicos , Células Th2/inmunologíaRESUMEN
Naive CD4+ T cells differentiate into functionally diverse T helper (Th) cell subsets. Th2 cells play a pathogenic role in asthma, yet a clear picture of their transcriptional profile is lacking. We performed single-cell RNA sequencing (scRNA-seq) of T helper cells from lymph node, lung, and airways in the house dust mite (HDM) model of allergic airway disease. scRNA-seq resolved transcriptional profiles of naive CD4+ T, Th1, Th2, regulatory T (Treg) cells, and a CD4+ T cell population responsive to type I interferons. Th2 cells in the airways were enriched for transcription of many genes, including Cd200r1, Il6, Plac8, and Igfbp7, and their mRNA profile was supported by analysis of chromatin accessibility and flow cytometry. Pathways associated with lipid metabolism were enriched in Th2 cells, and experiments with inhibitors of key metabolic pathways supported roles for glucose and lipid metabolism. These findings provide insight into the differentiation of pathogenic Th2 cells in the context of allergy.
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Asma/inmunología , Hipersensibilidad Respiratoria/inmunología , Sistema Respiratorio/inmunología , Subgrupos de Linfocitos T/inmunología , Células Th2/inmunología , Animales , Antígenos Dermatofagoides/inmunología , Modelos Animales de Enfermedad , Humanos , Metabolismo de los Lípidos/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores de Orexina/genética , Pyroglyphidae/inmunología , Análisis de Secuencia de ARN , Análisis de la Célula Individual , TranscriptomaRESUMEN
Macrophages are strongly adapted to their tissue of residence. Yet, little is known about the cell-cell interactions that imprint the tissue-specific identities of macrophages in their respective niches. Using conditional depletion of liver Kupffer cells, we traced the developmental stages of monocytes differentiating into Kupffer cells and mapped the cellular interactions imprinting the Kupffer cell identity. Kupffer cell loss induced tumor necrosis factor (TNF)- and interleukin-1 (IL-1) receptor-dependent activation of stellate cells and endothelial cells, resulting in the transient production of chemokines and adhesion molecules orchestrating monocyte engraftment. Engrafted circulating monocytes transmigrated into the perisinusoidal space and acquired the liver-associated transcription factors inhibitor of DNA 3 (ID3) and liver X receptor-α (LXR-α). Coordinated interactions with hepatocytes induced ID3 expression, whereas endothelial cells and stellate cells induced LXR-α via a synergistic NOTCH-BMP pathway. This study shows that the Kupffer cell niche is composed of stellate cells, hepatocytes, and endothelial cells that together imprint the liver-specific macrophage identity.
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Células Endoteliales/fisiología , Células Estrelladas Hepáticas/fisiología , Hepatocitos/fisiología , Macrófagos del Hígado/fisiología , Hígado/citología , Macrófagos/fisiología , Monocitos/fisiología , Animales , Comunicación Celular , Diferenciación Celular , Células Cultivadas , Microambiente Celular , Femenino , Regulación de la Expresión Génica , Proteínas Inhibidoras de la Diferenciación/genética , Proteínas Inhibidoras de la Diferenciación/metabolismo , Receptores X del Hígado/genética , Receptores X del Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Receptores Notch/metabolismoRESUMEN
Asthma is a common disease that affects 300 million people worldwide. Given the large number of eosinophils in the airways of people with mild asthma, and verified by data from murine models, asthma was long considered the hallmark T helper type 2 (TH2) disease of the airways. It is now known that some asthmatic inflammation is neutrophilic, controlled by the TH17 subset of helper T cells, and that some eosinophilic inflammation is controlled by type 2 innate lymphoid cells (ILC2 cells) acting together with basophils. Here we discuss results from in-depth molecular studies of mouse models in light of the results from the first clinical trials targeting key cytokines in humans and describe the extraordinary heterogeneity of asthma.