RESUMEN
Mycobacterium tuberculosis (Mtb) causes 1.6 million deaths annually. Active tuberculosis correlates with a neutrophil-driven type I interferon (IFN) signature, but the cellular mechanisms underlying tuberculosis pathogenesis remain poorly understood. We found that interstitial macrophages (IMs) and plasmacytoid dendritic cells (pDCs) are dominant producers of type I IFN during Mtb infection in mice and non-human primates, and pDCs localize near human Mtb granulomas. Depletion of pDCs reduces Mtb burdens, implicating pDCs in tuberculosis pathogenesis. During IFN-driven disease, we observe abundant DNA-containing neutrophil extracellular traps (NETs) described to activate pDCs. Cell-type-specific disruption of the type I IFN receptor suggests that IFNs act on IMs to inhibit Mtb control. Single-cell RNA sequencing (scRNA-seq) indicates that type I IFN-responsive cells are defective in their response to IFNγ, a cytokine critical for Mtb control. We propose that pDC-derived type I IFNs act on IMs to permit bacterial replication, driving further neutrophil recruitment and active tuberculosis disease.
Asunto(s)
Interferón Tipo I , Tuberculosis , Humanos , Ratones , Animales , Macrófagos/microbiología , Citocinas , Neutrófilos , Células DendríticasRESUMEN
The human pathogen Mycobacterium tuberculosis typically causes lung disease but can also disseminate to other tissues. We identified a M. tuberculosis (Mtb) outbreak presenting with unusually high rates of extrapulmonary dissemination and bone disease. We found that the causal strain carried an ancestral full-length version of the type VII-secreted effector EsxM rather than the truncated version present in other modern Mtb lineages. The ancestral EsxM variant exacerbated dissemination through enhancement of macrophage motility, increased egress of macrophages from established granulomas, and alterations in macrophage actin dynamics. Reconstitution of the ancestral version of EsxM in an attenuated modern strain of Mtb altered the migratory mode of infected macrophages, enhancing their motility. In a zebrafish model, full-length EsxM promoted bone disease. The presence of a derived nonsense variant in EsxM throughout the major Mtb lineages 2, 3, and 4 is consistent with a role for EsxM in regulating the extent of dissemination.
Asunto(s)
Enfermedades Óseas , Mycobacterium marinum , Mycobacterium tuberculosis , Tuberculosis , Animales , Humanos , Pez Cebra , Tuberculosis/microbiología , Macrófagos/microbiología , Proteínas Bacterianas/genéticaRESUMEN
Pulmonary tuberculosis, a disease caused by Mycobacterium tuberculosis (Mtb), manifests with a persistent cough as both a primary symptom and mechanism of transmission. The cough reflex can be triggered by nociceptive neurons innervating the lungs, and some bacteria produce neuron-targeting molecules. However, how pulmonary Mtb infection causes cough remains undefined, and whether Mtb produces a neuron-activating, cough-inducing molecule is unknown. Here, we show that an Mtb organic extract activates nociceptive neurons in vitro and identify the Mtb glycolipid sulfolipid-1 (SL-1) as the nociceptive molecule. Mtb organic extracts from mutants lacking SL-1 synthesis cannot activate neurons in vitro or induce cough in a guinea pig model. Finally, Mtb-infected guinea pigs cough in a manner dependent on SL-1 synthesis. Thus, we demonstrate a heretofore unknown molecular mechanism for cough induction by a virulent human pathogen via its production of a complex lipid.
Asunto(s)
Tos/fisiopatología , Glucolípidos/metabolismo , Nociceptores/fisiología , Factores de Virulencia/metabolismo , Adulto , Animales , Línea Celular , Tos/etiología , Tos/microbiología , Femenino , Glucolípidos/fisiología , Cobayas , Interacciones Huésped-Patógeno , Humanos , Lípidos/fisiología , Pulmón/microbiología , Macrófagos/microbiología , Masculino , Ratones , Mycobacterium tuberculosis/metabolismo , Mycobacterium tuberculosis/patogenicidad , Cultivo Primario de Células , Tuberculosis/microbiología , Tuberculosis Pulmonar/microbiología , Tuberculosis Pulmonar/fisiopatología , Factores de Virulencia/fisiologíaRESUMEN
Necrosis of infected macrophages constitutes a critical pathogenetic event in tuberculosis by releasing mycobacteria into the growth-permissive extracellular environment. In zebrafish infected with Mycobacterium marinum or Mycobacterium tuberculosis, excess tumor necrosis factor triggers programmed necrosis of infected macrophages through the production of mitochondrial reactive oxygen species (ROS) and the participation of cyclophilin D, a component of the mitochondrial permeability transition pore. Here, we show that this necrosis pathway is not mitochondrion-intrinsic but results from an inter-organellar circuit initiating and culminating in the mitochondrion. Mitochondrial ROS induce production of lysosomal ceramide that ultimately activates the cytosolic protein BAX. BAX promotes calcium flow from the endoplasmic reticulum into the mitochondrion through ryanodine receptors, and the resultant mitochondrial calcium overload triggers cyclophilin-D-mediated necrosis. We identify ryanodine receptors and plasma membrane L-type calcium channels as druggable targets to intercept mitochondrial calcium overload and necrosis of mycobacterium-infected zebrafish and human macrophages.
Asunto(s)
Macrófagos/microbiología , Macrófagos/patología , Mitocondrias/metabolismo , Infecciones por Mycobacterium no Tuberculosas/metabolismo , Tuberculosis/inmunología , Tuberculosis/patología , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Apoptosis , Calcio/metabolismo , Retículo Endoplásmico/microbiología , Humanos , Lisosomas/microbiología , Potencial de la Membrana Mitocondrial , Infecciones por Mycobacterium no Tuberculosas/patología , Mycobacterium marinum , Mycobacterium tuberculosis , Necrosis , Especies Reactivas de Oxígeno/metabolismo , Células THP-1 , Pez CebraRESUMEN
Granulomas are complex cellular structures composed predominantly of macrophages and lymphocytes that function to contain and kill invading pathogens. Here, we investigated the single-cell phenotypes associated with antimicrobial responses in human leprosy granulomas by applying single-cell and spatial sequencing to leprosy biopsy specimens. We focused on reversal reactions (RRs), a dynamic process whereby some patients with disseminated lepromatous leprosy (L-lep) transition toward self-limiting tuberculoid leprosy (T-lep), mounting effective antimicrobial responses. We identified a set of genes encoding proteins involved in antimicrobial responses that are differentially expressed in RR versus L-lep lesions and regulated by interferon-γ and interleukin-1ß. By integrating the spatial coordinates of the key cell types and antimicrobial gene expression in RR and T-lep lesions, we constructed a map revealing the organized architecture of granulomas depicting compositional and functional layers by which macrophages, T cells, keratinocytes and fibroblasts can each contribute to the antimicrobial response.
Asunto(s)
Lepra Lepromatosa/inmunología , Lepra Tuberculoide/inmunología , Mycobacterium leprae/inmunología , Piel/inmunología , Adolescente , Adulto , Anciano , Femenino , Fibroblastos/inmunología , Fibroblastos/microbiología , Fibroblastos/patología , Perfilación de la Expresión Génica , Interacciones Huésped-Patógeno , Humanos , Queratinocitos/inmunología , Queratinocitos/microbiología , Queratinocitos/patología , Lepra Lepromatosa/genética , Lepra Lepromatosa/microbiología , Lepra Lepromatosa/patología , Lepra Tuberculoide/genética , Lepra Tuberculoide/microbiología , Lepra Tuberculoide/patología , Macrófagos/inmunología , Macrófagos/microbiología , Macrófagos/patología , Masculino , Persona de Mediana Edad , Mycobacterium leprae/patogenicidad , RNA-Seq , Análisis de la Célula Individual , Piel/microbiología , Piel/patología , Linfocitos T/inmunología , Linfocitos T/microbiología , Linfocitos T/patología , TranscriptomaRESUMEN
Inflammasome activation is critical for host defenses against various microbial infections. Activation of the NLRC4 inflammasome requires detection of flagellin or type III secretion system (T3SS) components by NLR family apoptosis inhibitory proteins (NAIPs); yet how this pathway is regulated is unknown. Here, we found that interferon regulatory factor 8 (IRF8) is required for optimal activation of the NLRC4 inflammasome in bone-marrow-derived macrophages infected with Salmonella Typhimurium, Burkholderia thailandensis, or Pseudomonas aeruginosa but is dispensable for activation of the canonical and non-canonical NLRP3, AIM2, and Pyrin inflammasomes. IRF8 governs the transcription of Naips to allow detection of flagellin or T3SS proteins to mediate NLRC4 inflammasome activation. Furthermore, we found that IRF8 confers protection against bacterial infection in vivo, owing to its role in inflammasome-dependent cytokine production and pyroptosis. Altogether, our findings suggest that IRF8 is a critical regulator of NAIPs and NLRC4 inflammasome activation for defense against bacterial infection.
Asunto(s)
Proteínas Reguladoras de la Apoptosis/metabolismo , Proteínas de Unión al Calcio/metabolismo , Inflamasomas/metabolismo , Factores Reguladores del Interferón/metabolismo , Proteína Inhibidora de la Apoptosis Neuronal/metabolismo , Animales , Proteínas Reguladoras de la Apoptosis/genética , Proteínas de Unión al Calcio/genética , Células Cultivadas , Citocinas/metabolismo , Ensayo de Cambio de Movilidad Electroforética , Flagelina/metabolismo , Factores Reguladores del Interferón/antagonistas & inhibidores , Factores Reguladores del Interferón/genética , Macrófagos/citología , Macrófagos/metabolismo , Macrófagos/microbiología , Ratones , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Proteína Inhibidora de la Apoptosis Neuronal/genética , Regiones Promotoras Genéticas , Unión Proteica , Pseudomonas aeruginosa/patogenicidad , Piroptosis , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Salmonella typhimurium/patogenicidad , Transcripción GenéticaRESUMEN
Cells use mitophagy to remove damaged or unwanted mitochondria to maintain homeostasis. Here we report that the intracellular bacterial pathogen Listeria monocytogenes exploits host mitophagy to evade killing. We found that L. monocytogenes induced mitophagy in macrophages through the virulence factor listeriolysin O (LLO). We discovered that NLRX1, the only Nod-like receptor (NLR) family member with a mitochondrial targeting sequence, contains an LC3-interacting region (LIR) and directly associated with LC3 through the LIR. NLRX1 and its LIR motif were essential for L. monocytogenes-induced mitophagy. NLRX1 deficiency and use of a mitophagy inhibitor both increased mitochondrial production of reactive oxygen species and thereby suppressed the survival of L. monocytogenes. Mechanistically, L. monocytogenes and LLO induced oligomerization of NLRX1 to promote binding of its LIR motif to LC3 for induction of mitophagy. Our study identifies NLRX1 as a novel mitophagy receptor and discovers a previously unappreciated strategy used by pathogens to hijack a host cell homeostasis system for their survival.
Asunto(s)
Listeria monocytogenes/fisiología , Proteínas Mitocondriales/fisiología , Mitofagia , Animales , Autofagia , Toxinas Bacterianas/metabolismo , Línea Celular , Femenino , Proteínas de Choque Térmico/metabolismo , Proteínas Hemolisinas/metabolismo , Humanos , Listeria monocytogenes/patogenicidad , Listeriosis/metabolismo , Listeriosis/microbiología , Macrófagos/microbiología , Macrófagos/ultraestructura , Masculino , Ratones , Ratones Noqueados , Viabilidad Microbiana , Mitocondrias/metabolismo , Mitocondrias/ultraestructura , Proteínas Mitocondriales/química , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Dominios Proteicos , Especies Reactivas de Oxígeno/metabolismo , Factores de Virulencia/metabolismoRESUMEN
Long intergenic noncoding RNAs (lincRNAs) are important regulators of gene expression. Although lincRNAs are expressed in immune cells, their functions in immunity are largely unexplored. Here, we identify an immunoregulatory lincRNA, lincRNA-EPS, that is precisely regulated in macrophages to control the expression of immune response genes (IRGs). Transcriptome analysis of macrophages from lincRNA-EPS-deficient mice, combined with gain-of-function and rescue experiments, revealed a specific role for this lincRNA in restraining IRG expression. Consistently, lincRNA-EPS-deficient mice manifest enhanced inflammation and lethality following endotoxin challenge in vivo. lincRNA-EPS localizes at regulatory regions of IRGs to control nucleosome positioning and repress transcription. Further, lincRNA-EPS mediates these effects by interacting with heterogeneous nuclear ribonucleoprotein L via a CANACA motif located in its 3' end. Together, these findings identify lincRNA-EPS as a repressor of inflammatory responses, highlighting the importance of lincRNAs in the immune system.
Asunto(s)
Regulación de la Expresión Génica , Inflamación/genética , Macrófagos/inmunología , ARN Largo no Codificante/metabolismo , Animales , Cromátides/metabolismo , Eliminación de Gen , Humanos , Listeria monocytogenes/fisiología , Listeriosis/inmunología , Macrófagos/metabolismo , Macrófagos/microbiología , Macrófagos/virología , Ratones , Ratones Endogámicos C57BL , ARN Largo no Codificante/genética , Infecciones por Respirovirus/inmunología , Virus Sendai/fisiología , Receptores Toll-Like/metabolismo , TranscriptomaRESUMEN
Interactions between intracellular bacteria and mononuclear phagocytes give rise to diverse cellular phenotypes that may determine the outcome of infection. Recent advances in single-cell RNA sequencing (scRNA-seq) have identified multiple subsets within the mononuclear population, but implications to their function during infection are limited. Here, we surveyed the mononuclear niche of intracellular Salmonella Typhimurium (S.Tm) during early systemic infection in mice. We described eclipse-like growth kinetics in the spleen, with a first phase of bacterial control mediated by tissue-resident red-pulp macrophages. A second phase involved extensive bacterial replication within a macrophage population characterized by CD9 expression. We demonstrated that CD9+ macrophages induced pathways for detoxificating oxidized lipids, that may be utilized by intracellular S.Tm. We established that CD9+ macrophages originated from non-classical monocytes (NCM), and NCM-depleted mice were more resistant to S.Tm infection. Our study defines macrophage subset-specific host-pathogen interactions that determine early infection dynamics and infection outcome of the entire organism.
Asunto(s)
Macrófagos/inmunología , Infecciones por Salmonella/inmunología , Salmonella typhimurium/fisiología , Bazo/inmunología , Animales , Interacciones Huésped-Patógeno , Humanos , Espacio Intracelular , Metabolismo de los Lípidos , Macrófagos/microbiología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Oxidación-Reducción , Análisis de la Célula Individual , Bazo/microbiología , Tetraspanina 29/metabolismoRESUMEN
Apoptosis can potently defend against intracellular pathogens by directly killing microbes and eliminating their replicative niche. However, the reported ability of Mycobacterium tuberculosis to restrict apoptotic pathways in macrophages in vitro has led to apoptosis being dismissed as a host-protective process in tuberculosis despite a lack of in vivo evidence. Here we define crucial in vivo functions of the death receptor-mediated and BCL-2-regulated apoptosis pathways in mediating protection against tuberculosis by eliminating distinct populations of infected macrophages and neutrophils and priming T cell responses. We further show that apoptotic pathways can be targeted therapeutically with clinical-stage compounds that antagonize inhibitor of apoptosis (IAP) proteins to promote clearance of M. tuberculosis in mice. These findings reveal that any inhibition of apoptosis by M. tuberculosis is incomplete in vivo, advancing our understanding of host-protective responses to tuberculosis (TB) and revealing host pathways that may be targetable for treatment of disease.
Asunto(s)
Apoptosis/inmunología , Macrófagos/inmunología , Mycobacterium tuberculosis/inmunología , Neutrófilos/inmunología , Tuberculosis Pulmonar/inmunología , Animales , Caspasa 8/genética , Caspasa 8/metabolismo , Línea Celular , Dipéptidos/uso terapéutico , Humanos , Indoles/uso terapéutico , Activación de Linfocitos/inmunología , Macrófagos/microbiología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neutrófilos/microbiología , Proteínas Quinasas/genética , Proteínas Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Linfocitos T/inmunología , Tiazoles/uso terapéutico , Tuberculosis Pulmonar/tratamiento farmacológicoRESUMEN
Innate immune pattern recognition receptors, such as the Toll-like receptors (TLRs), are key mediators of the immune response to infection and central to our understanding of health and disease1. After microbial detection, these receptors activate inflammatory signal transduction pathways that involve IκB kinases, mitogen-activated protein kinases, ubiquitin ligases and other adaptor proteins. The mechanisms that connect the proteins in the TLR pathways are poorly defined. To delineate TLR pathway activities, we engineered macrophages to enable microscopy and proteomic analysis of the endogenous myddosome constituent MyD88. We found that myddosomes form transient contacts with activated TLRs and that TLR-free myddosomes are dynamic in size, number and composition over the course of 24 h. Analysis using super-resolution microscopy revealed that, within most myddosomes, MyD88 forms barrel-like structures that function as scaffolds for effector protein recruitment. Proteomic analysis demonstrated that myddosomes contain proteins that act at all stages and regulate all effector responses of the TLR pathways, and genetic analysis defined the epistatic relationship between these effector modules. Myddosome assembly was evident in cells infected with Listeria monocytogenes, but these bacteria evaded myddosome assembly and TLR signalling during cell-to-cell spread. On the basis of these findings, we propose that the entire TLR signalling pathway is executed from within the myddosome.
Asunto(s)
Macrófagos , Transducción de Señal , Receptores Toll-Like , Animales , Humanos , Ratones , Listeria monocytogenes/inmunología , Listeriosis/inmunología , Listeriosis/microbiología , Listeriosis/metabolismo , Macrófagos/inmunología , Macrófagos/metabolismo , Macrófagos/microbiología , Factor 88 de Diferenciación Mieloide/metabolismo , Proteómica , Receptores Toll-Like/metabolismo , Microscopía , Inmunidad InnataRESUMEN
Phagocytosis is the process by which myeloid phagocytes bind to and internalize potentially dangerous microorganisms1. During phagocytosis, innate immune receptors and associated signalling proteins are localized to the maturing phagosome compartment, forming an immune information processing hub brimming with microorganism-sensing features2-8. Here we developed proximity labelling of phagosomal contents (PhagoPL) to identify proteins localizing to phagosomes containing model yeast and bacteria. By comparing the protein composition of phagosomes containing evolutionarily and biochemically distinct microorganisms, we unexpectedly identified programmed death-ligand 1 (PD-L1) as a protein that specifically enriches in phagosomes containing yeast. We found that PD-L1 directly binds to yeast upon processing in phagosomes. By surface display library screening, we identified the ribosomal protein Rpl20b as a fungal protein ligand for PD-L1. Using an auxin-inducible depletion system, we found that detection of Rpl20b by macrophages cross-regulates production of distinct cytokines including interleukin-10 (IL-10) induced by the activation of other innate immune receptors. Thus, this study establishes PhagoPL as a useful approach to quantifying the collection of proteins enriched in phagosomes during host-microorganism interactions, exemplified by identifying PD-L1 as a receptor that binds to fungi.
Asunto(s)
Antígeno B7-H1 , Proteínas Fúngicas , Fagosomas , Proteínas Ribosómicas , Saccharomyces cerevisiae , Animales , Femenino , Humanos , Masculino , Ratones , Antígeno B7-H1/metabolismo , Escherichia coli/metabolismo , Proteínas Fúngicas/metabolismo , Interacciones Microbiota-Huesped , Inmunidad Innata , Interleucina-10/metabolismo , Ligandos , Macrófagos/metabolismo , Macrófagos/inmunología , Macrófagos/microbiología , Ratones Endogámicos BALB C , Fagocitosis , Fagosomas/química , Fagosomas/metabolismo , Fagosomas/microbiología , Unión Proteica , Proteínas Ribosómicas/metabolismo , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/metabolismo , Staphylococcus aureus/metabolismoRESUMEN
Tuberculosis, an ancient disease of mankind, remains one of the major infectious causes of human death. We examine newly discovered facets of tuberculosis pathogenesis and explore the evolution of its causative organism Mycobacterium tuberculosis from soil dweller to human pathogen. M. tuberculosis has coevolved with the human host to evade and exploit host macrophages and other immune cells in multiple ways. Though the host can often clear infection, the organism can cause transmissible disease in enough individuals to sustain itself. Tuberculosis is a near-perfect paradigm of a host-pathogen relationship, and that may be the challenge to the development of new therapies for its eradication.
Asunto(s)
Evasión Inmune , Mycobacterium tuberculosis/inmunología , Tuberculosis/microbiología , Animales , Granuloma/inmunología , Granuloma/microbiología , Humanos , Macrófagos/inmunología , Macrófagos/microbiología , Tuberculosis/inmunologíaRESUMEN
Endomembrane damage represents a form of stress that is detrimental for eukaryotic cells1,2. To cope with this threat, cells possess mechanisms that repair the damage and restore cellular homeostasis3-7. Endomembrane damage also results in organelle instability and the mechanisms by which cells stabilize damaged endomembranes to enable membrane repair remains unknown. Here, by combining in vitro and in cellulo studies with computational modelling we uncover a biological function for stress granules whereby these biomolecular condensates form rapidly at endomembrane damage sites and act as a plug that stabilizes the ruptured membrane. Functionally, we demonstrate that stress granule formation and membrane stabilization enable efficient repair of damaged endolysosomes, through both ESCRT (endosomal sorting complex required for transport)-dependent and independent mechanisms. We also show that blocking stress granule formation in human macrophages creates a permissive environment for Mycobacterium tuberculosis, a human pathogen that exploits endomembrane damage to survive within the host.
Asunto(s)
Endosomas , Membranas Intracelulares , Lisosomas , Macrófagos , Gránulos de Estrés , Humanos , Complejos de Clasificación Endosomal Requeridos para el Transporte/metabolismo , Endosomas/metabolismo , Endosomas/microbiología , Endosomas/patología , Membranas Intracelulares/metabolismo , Membranas Intracelulares/microbiología , Membranas Intracelulares/patología , Lisosomas/metabolismo , Lisosomas/microbiología , Lisosomas/patología , Mycobacterium tuberculosis/metabolismo , Gránulos de Estrés/metabolismo , Técnicas In Vitro , Macrófagos/metabolismo , Macrófagos/microbiología , Macrófagos/patologíaRESUMEN
Mycobacterium tuberculosis (Mtb) survives in macrophages by evading delivery to the lysosome and promoting the accumulation of lipid bodies, which serve as a bacterial source of nutrients. We found that by inducing the microRNA (miRNA) miR-33 and its passenger strand miR-33*, Mtb inhibited integrated pathways involved in autophagy, lysosomal function and fatty acid oxidation to support bacterial replication. Silencing of miR-33 and miR-33* by genetic or pharmacological means promoted autophagy flux through derepression of key autophagy effectors (such as ATG5, ATG12, LC3B and LAMP1) and AMPK-dependent activation of the transcription factors FOXO3 and TFEB, which enhanced lipid catabolism and Mtb xenophagy. These data define a mammalian miRNA circuit used by Mtb to coordinately inhibit autophagy and reprogram host lipid metabolism to enable intracellular survival and persistence in the host.
Asunto(s)
Autofagia/genética , Metabolismo de los Lípidos/genética , Lisosomas/fisiología , Macrófagos/fisiología , MicroARNs/metabolismo , Mycobacterium tuberculosis/fisiología , Tuberculosis/genética , Animales , Células Cultivadas , Interacciones Huésped-Patógeno , Humanos , Evasión Inmune , Lisosomas/microbiología , Macrófagos/microbiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , MicroARNs/genética , Transducción de Señal , Factores de Transcripción/metabolismoRESUMEN
The respiratory tract is heavily populated with innate immune cells, but the mechanisms that control such cells are poorly defined. Here we found that the E3 ubiquitin ligase TRIM29 was a selective regulator of the activation of alveolar macrophages, the expression of type I interferons and the production of proinflammatory cytokines in the lungs. We found that deletion of TRIM29 enhanced macrophage production of type I interferons and protected mice from infection with influenza virus, while challenge of Trim29-/- mice with Haemophilus influenzae resulted in lethal lung inflammation due to massive production of proinflammatory cytokines by macrophages. Mechanistically, we demonstrated that TRIM29 inhibited interferon-regulatory factors and signaling via the transcription factor NF-κB by degrading the adaptor NEMO and that TRIM29 directly bound NEMO and subsequently induced its ubiquitination and proteolytic degradation. These data identify TRIM29 as a key negative regulator of alveolar macrophages and might have important clinical implications for local immunity and immunopathology.
Asunto(s)
Infecciones por Haemophilus/inmunología , Haemophilus influenzae/inmunología , Virus de la Influenza A/inmunología , Macrófagos/inmunología , Infecciones por Orthomyxoviridae/inmunología , Sistema Respiratorio/inmunología , Factores de Transcripción/metabolismo , Animales , Células Cultivadas , Inmunidad Innata , Interferón Tipo I/genética , Interferón Tipo I/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Macrófagos/microbiología , Macrófagos/virología , Ratones , Ratones Noqueados , FN-kappa B/metabolismo , Proteolisis , Transducción de Señal , Factores de Transcripción/genética , UbiquitinaciónRESUMEN
Resident macrophages densely populate the normal arterial wall, yet their origins and the mechanisms that sustain them are poorly understood. Here we use gene-expression profiling to show that arterial macrophages constitute a distinct population among macrophages. Using multiple fate-mapping approaches, we show that arterial macrophages arise embryonically from CX3CR1(+) precursors and postnatally from bone marrow-derived monocytes that colonize the tissue immediately after birth. In adulthood, proliferation (rather than monocyte recruitment) sustains arterial macrophages in the steady state and after severe depletion following sepsis. After infection, arterial macrophages return rapidly to functional homeostasis. Finally, survival of resident arterial macrophages depends on a CX3CR1-CX3CL1 axis within the vascular niche.
Asunto(s)
Autorrenovación de las Células , Células Madre Embrionarias/citología , Células Madre Embrionarias/metabolismo , Macrófagos/citología , Macrófagos/metabolismo , Monocitos/citología , Monocitos/metabolismo , Receptores de Quimiocina/metabolismo , Animales , Receptor 1 de Quimiocinas CX3C , Supervivencia Celular , Quimiocina CX3CL1/metabolismo , Análisis por Conglomerados , Femenino , Perfilación de la Expresión Génica , Inmunofenotipificación , Macrófagos/inmunología , Macrófagos/microbiología , Masculino , Ratones , Ratones Transgénicos , Fenotipo , Unión Proteica , Nicho de Células Madre , TranscriptomaRESUMEN
Hemolysis drives susceptibility to bacterial infections and predicts poor outcome from sepsis. These detrimental effects are commonly considered to be a consequence of heme-iron serving as a nutrient for bacteria. We employed a Gram-negative sepsis model and found that elevated heme levels impaired the control of bacterial proliferation independently of heme-iron acquisition by pathogens. Heme strongly inhibited phagocytosis and the migration of human and mouse phagocytes by disrupting actin cytoskeletal dynamics via activation of the GTP-binding Rho family protein Cdc42 by the guanine nucleotide exchange factor DOCK8. A chemical screening approach revealed that quinine effectively prevented heme effects on the cytoskeleton, restored phagocytosis and improved survival in sepsis. These mechanistic insights provide potential therapeutic targets for patients with sepsis or hemolytic disorders.
Asunto(s)
Infecciones por Bacterias Gramnegativas/inmunología , Factores de Intercambio de Guanina Nucleótido/metabolismo , Hemo/metabolismo , Hemólisis/inmunología , Macrófagos/inmunología , Fagocitosis , Sepsis/inmunología , Animales , Antibacterianos/uso terapéutico , Citoesqueleto/metabolismo , Femenino , Infecciones por Bacterias Gramnegativas/tratamiento farmacológico , Factores de Intercambio de Guanina Nucleótido/genética , Hemo-Oxigenasa 1/genética , Hemólisis/efectos de los fármacos , Humanos , Evasión Inmune , Macrófagos/efectos de los fármacos , Macrófagos/microbiología , Proteínas de la Membrana/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fagocitosis/efectos de los fármacos , Quinina/uso terapéutico , Células RAW 264.7 , Sepsis/tratamiento farmacológico , Proteína de Unión al GTP cdc42/metabolismoRESUMEN
Host microbial cross-talk is essential to maintain intestinal homeostasis. However, maladaptation of this response through microbial dysbiosis or defective host defense toward invasive intestinal bacteria can result in chronic inflammation. We have shown that macrophages differentiated in the presence of the bacterial metabolite butyrate display enhanced antimicrobial activity. Butyrate-induced antimicrobial activity was associated with a shift in macrophage metabolism, a reduction in mTOR kinase activity, increased LC3-associated host defense and anti-microbial peptide production in the absence of an increased inflammatory cytokine response. Butyrate drove this monocyte to macrophage differentiation program through histone deacetylase 3 (HDAC3) inhibition. Administration of butyrate induced antimicrobial activity in intestinal macrophages in vivo and increased resistance to enteropathogens. Our data suggest that (1) increased intestinal butyrate might represent a strategy to bolster host defense without tissue damaging inflammation and (2) that pharmacological HDAC3 inhibition might drive selective macrophage functions toward antimicrobial host defense.
Asunto(s)
Antiinfecciosos/farmacología , Butiratos/farmacología , Diferenciación Celular/efectos de los fármacos , Macrófagos/efectos de los fármacos , Monocitos/efectos de los fármacos , Animales , Diferenciación Celular/genética , Células Cultivadas , Colon/efectos de los fármacos , Colon/metabolismo , Colon/microbiología , Citocinas/genética , Citocinas/metabolismo , Disbiosis/microbiología , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Intestinos/efectos de los fármacos , Intestinos/microbiología , Macrófagos/metabolismo , Macrófagos/microbiología , Ratones Endogámicos C57BL , Microbiota/efectos de los fármacos , Microbiota/fisiología , Monocitos/metabolismo , Monocitos/microbiologíaRESUMEN
Differentiated cells possess a remarkable genomic plasticity that can be manipulated to reverse or change developmental commitments. Here, we show that the leprosy bacterium hijacks this property to reprogram adult Schwann cells, its preferred host niche, to a stage of progenitor/stem-like cells (pSLC) of mesenchymal trait by downregulating Schwann cell lineage/differentiation-associated genes and upregulating genes mostly of mesoderm development. Reprogramming accompanies epigenetic changes and renders infected cells highly plastic, migratory, and immunomodulatory. We provide evidence that acquisition of these properties by pSLC promotes bacterial spread by two distinct mechanisms: direct differentiation to mesenchymal tissues, including skeletal and smooth muscles, and formation of granuloma-like structures and subsequent release of bacteria-laden macrophages. These findings support a model of host cell reprogramming in which a bacterial pathogen uses the plasticity of its cellular niche for promoting dissemination of infection and provide an unexpected link between cellular reprogramming and host-pathogen interaction.