RESUMEN
S100A8/A9 has important immunomodulatory roles in antibacterial defense, but its relevance in focal pneumonia caused by Streptococcus pneumoniae (S. pneumoniae) is understudied. We show that S100A9 was significantly increased in BAL fluids of patients with bacterial but not viral pneumonia and correlated with procalcitonin and sequential organ failure assessment scores. Mice deficient in S100A9 exhibited drastically elevated Zn2+ levels in lungs, which led to bacterial outgrowth and significantly reduced survival. In addition, reduced survival of S100A9 KO mice was characterized by excessive release of neutrophil elastase, which resulted in degradation of opsonophagocytically important collectins surfactant proteins A and D. All of these features were attenuated in S. pneumoniae-challenged chimeric WTâS100A9 KO mice. Similarly, therapy of S. pneumoniae-infected S100A9 KO mice with a mutant S100A8/A9 protein showing increased half-life significantly decreased lung bacterial loads and lung injury. Collectively, S100A9 controls central antibacterial immune mechanisms of the lung with essential relevance to survival of pneumococcal pneumonia. Moreover, S100A9 appears to be a promising biomarker to distinguish patients with bacterial from those with viral pneumonia. Trial registration: Clinical Trials register (DRKS00000620).
Asunto(s)
Neumonía Neumocócica , Ratones , Animales , Calgranulina B/genética , Calgranulina B/metabolismo , Pulmón , Streptococcus pneumoniae/metabolismo , Calgranulina A/genética , Calgranulina A/metabolismo , Bacterias/metabolismo , Ratones NoqueadosRESUMEN
Staphylococcus aureus is a prevalent pathogen in pneumonia and harbors glycolipids, which may serve as molecular patterns in Mincle (macrophage-inducible C-type lectin)-dependent pathogen recognition. We examined the role of Mincle in lung defense against S aureus in wild-type (WT), Mincle knockout (KO), and Mincle transgenic (tg) mice. Two glycolipids, glucosyl-diacylglycerol (Glc-DAG) and diglucosyl-diacylglycerol (Glc2-DAG), were purified, of which only Glc-DAG triggered Mincle reporter cell activation and professional phagocyte responses. Proteomic profiling revealed that Glc2-DAG blocked Glc-DAG-induced cytokine responses, thereby acting as inhibitor of Glc-DAG/Mincle signaling. WT mice responded to S aureus with a similar lung pathology as Mincle KO mice, most likely due to Glc2-DAG-dependent inhibition of Glc-DAG/Mincle signaling. In contrast, ectopic Mincle expression caused severe lung pathology in S aureus-infected mice, characterized by bacterial outgrowth and fatal pneumonia. Collectively, Glc2-DAG inhibits Glc-DAG/Mincle-dependent responses in WT mice, whereas sustained Mincle expression overrides Glc2-DAG-mediated inhibitory effects, conferring increased host susceptibility to S aureus.
Asunto(s)
Lectinas Tipo C , Proteínas de la Membrana , Ratones Noqueados , Neumonía Estafilocócica , Staphylococcus aureus , Animales , Lectinas Tipo C/metabolismo , Lectinas Tipo C/genética , Neumonía Estafilocócica/microbiología , Neumonía Estafilocócica/inmunología , Ratones , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Pulmón/microbiología , Pulmón/patología , Ratones Transgénicos , Ratones Endogámicos C57BL , Transducción de Señal , Susceptibilidad a Enfermedades , Citocinas/metabolismoRESUMEN
The pathomechanisms underlying the frequently observed fatal outcome of Klebsiella pneumoniae pneumonia in elderly patients are understudied. In this study, we examined the early antibacterial immune response in young mice (age 2-3 mo) as compared with old mice (age 18-19 mo) postinfection with K. pneumoniae. Old mice exhibited significantly higher bacterial loads in lungs and bacteremia as early as 24 h postinfection compared with young mice, with neutrophilic pleuritis nearly exclusively developing in old but not young mice. Moreover, we observed heavily increased cytokine responses in lungs and pleural spaces along with increased mortality in old mice. Mechanistically, Nlrp3 inflammasome activation and caspase-1-dependent IL-1ß secretion contributed to the observed hyperinflammation, which decreased upon caspase-1 inhibitor treatment of K. pneumoniae-infected old mice. Irradiated old mice transplanted with the bone marrow of young mice did not show hyperinflammation or early bacteremia in response to K. pneumoniae. Collectively, the accentuated lung pathology observed in K. pneumoniae-infected old mice appears to be due to regulatory defects of the bone marrow but not the lung, while involving dysregulated activation of the Nlrp3/caspase-1/IL-1ß axis.
Asunto(s)
Bacteriemia , Pleuresia , Neumonía , Ratones , Animales , Klebsiella , Klebsiella pneumoniae , Proteína con Dominio Pirina 3 de la Familia NLR , Caspasa 1RESUMEN
BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a diffuse parenchymal lung disease characterized by exuberant deposition of extracellular matrix (ECM) proteins in the lung interstitium, which contributes to substantial morbidity and mortality in IPF patients. Matrix metalloproteinases (MMPs) are a large family of zinc-dependent endopeptidases, many of which have been implicated in the regulation of ECM degradation in lung fibrosis. However, the roles of MMP-2 and -9 (also termed gelatinases A and B) have not yet been explored in lung fibrosis in detail. METHODS: AdTGF-ß1 was applied via orotracheal routes to the lungs of WT, MMP-2 KO, MMP-9 KO and MMP-2/-9 dKO mice on day 0 to induce lung fibrosis. Using hydroxyproline assay, FlexiVent based lung function measurement, histopathology, western blot and ELISA techniques, we analyzed MMP-2 and MMP-9 levels in BAL fluid and lung, collagen contents in lung and lung function in mice on day 14 and 21 post-treatment. RESULT: IPF lung homogenates exhibited significantly increased levels of MMP-2 and MMP-9, relative to disease controls. Enzymatically active MMP-2 and MMP-9 was increased in lungs of mice exposed to adenoviral TGF-ß1, suggesting a role for these metalloproteinases in lung fibrogenesis. However, we found that neither MMP-2 or MMP-9 nor combined MMP-2/-9 deletion had any effect on experimental lung fibrosis in mice. CONCLUSION: Together, our data strongly suggest that both gelatinases MMP-2 and MMP-9 play only a subordinate role in experimental lung fibrosis in mice.
Asunto(s)
Fibrosis Pulmonar Idiopática , Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 9 de la Matriz/metabolismo , Animales , Proteínas de la Matriz Extracelular/metabolismo , Fibrosis Pulmonar Idiopática/inducido químicamente , Fibrosis Pulmonar Idiopática/genética , Fibrosis Pulmonar Idiopática/metabolismo , Pulmón/metabolismo , Metaloproteinasa 2 de la Matriz/genética , Metaloproteinasa 9 de la Matriz/genética , Metaloproteinasas de la Matriz/metabolismo , RatonesRESUMEN
Patients with idiopathic pulmonary fibrosis (IPF) can experience life-threatening episodes of acute worsening of their disease, termed acute exacerbation of IPF, which may be caused by bacterial and/or viral infections. The potential for regulatory T cells (Tregs) to limit disease progression in bacterially triggered fibrosis exacerbation has not been explored so far. In the current study, we show that the number of Tregs was significantly increased in mice with established AdTGF-ß1-induced lung fibrosis and further increased in mice with pneumococcal infection-induced lung fibrosis exacerbation. Diphtheria toxin-induced depletion of Tregs significantly worsened infection-induced fibrosis exacerbation as determined by increased lung collagen deposition, lung histology, and elevated pulmonary Th1/Th2 cytokine levels. Conversely, IL-2 complex-induced Treg expansion in wild-type mice with established lung fibrosis completely inhibited pneumococcal infection-induced fibrosis exacerbation as efficaciously as antibiotic treatment while preserving lung antibacterial immunity in mice. Collectively, these findings demonstrate the efficacy of Tregs as "silencers," suppressing infection-induced exacerbation of lung fibrosis in mice, and their expansion may offer a novel adjunctive treatment to limit acute exacerbations in patients with IPF.
Asunto(s)
Fibrosis Pulmonar Idiopática/inmunología , Infecciones Neumocócicas/inmunología , Streptococcus pneumoniae/inmunología , Linfocitos T Reguladores/inmunología , Animales , Citocinas/inmunología , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Femenino , Fibrosis Pulmonar Idiopática/microbiología , Interleucina-2/inmunología , Pulmón/inmunología , Pulmón/microbiología , Masculino , Ratones , Ratones Endogámicos C57BL , Infecciones Neumocócicas/microbiología , Células TH1/inmunología , Células Th17/inmunologíaRESUMEN
Macrophage-inducible C-type lectin (Mincle)-dependent sensing of pathogens triggers proinflammatory immune responses in professional phagocytes that contribute to protecting the host against pathogen invasion. In this study, we examined whether overexpression of Mincle that is designed to improve early pathogen sensing by professional phagocytes would improve lung-protective immunity against Streptococcus pneumoniae in mice. Proteomic profiling of alveolar macrophages of Mincle transgenic (tg) mice stimulated with the Mincle-specific pneumococcal ligand glucosyl-diacylglycerol (Glc-DAG) revealed increased Nlrp3 inflammasome activation and downstream IL-1ß cytokine release that was not observed in Glc-DAG-stimulated Mincle knockout or Nlrp3 knockout macrophages. Along this line, Mincle tg mice also responded with a stronger Nlrp3 expression and early proinflammatory cytokine release after challenge with S. pneumoniae, ultimately leading to fatal pneumonia in the Mincle tg mice. Importantly, Nlrp3 inhibitor treatment of Mincle tg mice significantly mitigated the observed hyperinflammatory response to pneumococcal challenge. Together, we show that overexpression of the pattern recognition receptor Mincle triggers increased Glc-DAG-dependent Nlrp3 inflammasome activation in professional phagocytes leading to fatal pneumococcal pneumonia in mice that is amenable to Nlrp3 inhibitor treatment. These data show that ectopic expression of the Mincle receptor confers increased susceptibility rather than resistance to S. pneumoniae in mice, thus highlighting the importance of an inducible Mincle receptor expression in response to microbial challenge.
Asunto(s)
Lectinas Tipo C/inmunología , Macrófagos Alveolares/inmunología , Proteínas de la Membrana/inmunología , Neumonía Neumocócica/inmunología , Streptococcus pneumoniae/inmunología , Animales , Inflamasomas/genética , Inflamasomas/inmunología , Interleucina-1beta/genética , Interleucina-1beta/inmunología , Lectinas Tipo C/genética , Macrófagos Alveolares/patología , Proteínas de la Membrana/genética , Ratones , Ratones Transgénicos , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Proteína con Dominio Pirina 3 de la Familia NLR/inmunología , Neumonía Neumocócica/genética , Neumonía Neumocócica/patologíaRESUMEN
Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease (ILD) associated with high morbidity and mortality. Patients with ILD frequently develop an acute exacerbation of their disease, which may be triggered by viral and/or bacterial infections. Prostaglandin E2 (PGE2) is an eicosanoid released in a cyclooxygenase-2 (COX2)-dependent manner and is considered to contribute to regulation of lung fibrosis. However, its role in infection-induced exacerbation of lung fibrosis is poorly defined. We found significantly increased levels of PGE2 in lung tissue of patients with ILD. Increased levels of PGE2 were also found in lung tissue of mice with AdTGF-ß1-induced lung fibrosis and even more so in Streptococcus pneumoniae exacerbated lung fibrosis. Type II alveolar epithelial cells (AT II cells) and alveolar macrophages (AM) contributed to PGE2 release during exacerbating fibrosis. Application of parecoxib to inhibit PGE2 synthesis ameliorated lung fibrosis, whereas intratracheal application of PGE2 worsened lung fibrosis in mice. Both interventions had no effect on S. pneumoniae-exacerbated lung fibrosis. Together, we found that the COX2-PGE2 axis has dual roles in fibrosis that may offset each other: PGE2 helps resolve infection/attenuate inflammation in fibrosis exacerbation but accentuates TGF-ß/AT II cell-mediated fibrosis. These data support the efficacy of COX/PGE2 interventions in the setting of non-exacerbating lung fibrosis.
Asunto(s)
Células Epiteliales Alveolares/metabolismo , Ciclooxigenasa 2/metabolismo , Dinoprostona/metabolismo , Neumonía Neumocócica/metabolismo , Fibrosis Pulmonar/metabolismo , Transducción de Señal , Streptococcus pneumoniae/metabolismo , Células Epiteliales Alveolares/microbiología , Células Epiteliales Alveolares/patología , Animales , Modelos Animales de Enfermedad , Femenino , Isoxazoles/farmacología , Ratones , Neumonía Neumocócica/patología , Fibrosis Pulmonar/microbiología , Fibrosis Pulmonar/patología , Factor de Crecimiento Transformador beta/metabolismoRESUMEN
The cellular basis of immunological memory remains a controversial issue. Here we show that basophils bound large amounts of intact antigens on their surface and were the main source of interleukins 6 and 4 in the spleen and bone marrow after restimulation with a soluble antigen. Depletion of basophils resulted in a much lower humoral memory response and greater susceptibility of immunized mice to sepsis induced by Streptococcus pneumoniae. Adoptive transfer of antigen-reactive basophils significantly increased specific antibody production, and activated basophils, together with CD4(+) T cells, profoundly enhanced B cell proliferation and immunoglobulin production. These basophil-dependent effects on B cells required interleukins 6 and 4 and increased the capacity of CD4(+) T cells to provide B cell help. Thus, basophils are important contributors to humoral memory immune responses.
Asunto(s)
Basófilos/inmunología , Memoria Inmunológica , Traslado Adoptivo , Animales , Formación de Anticuerpos , Presentación de Antígeno/inmunología , Células Presentadoras de Antígenos/inmunología , Linfocitos B/inmunología , Médula Ósea/inmunología , Ensayo de Inmunoadsorción Enzimática , Femenino , Citometría de Flujo , Interleucina-4/biosíntesis , Interleucina-6/biosíntesis , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos C57BL , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Bazo/citología , Bazo/inmunología , Linfocitos T/inmunologíaRESUMEN
RATIONALE: Dendritic cells (DC) accumulate in the lungs of patients with idiopathic lung fibrosis, but their pathogenetic relevance is poorly defined. OBJECTIVES: To assess the role of the FMS-like tyrosine kinase-3 ligand (Flt3L)-lung dendritic cell axis in lung fibrosis. MEASUREMENTS AND MAIN RESULTS: We demonstrate in a model of adenoviral gene transfer of active TGF-ß1 that established lung fibrosis was accompanied by elevated serum Flt3L levels and subsequent accumulation of CD11bpos DC in the lungs of mice. Patients with idiopathic pulmonary fibrosis also demonstrated increased levels of Flt3L protein in serum and lung tissue and accumulation of lung DC in explant subpleural lung tissue specimen. Mice lacking Flt3L showed significantly reduced lung DC along with worsened lung fibrosis and reduced lung function relative to wild-type (WT) mice, which could be inhibited by administration of recombinant Flt3L. Moreover, therapeutic Flt3L increased numbers of CD11bpos DC and improved lung fibrosis in WT mice exposed to AdTGF-ß1. In this line, RNA-sequencing analysis of CD11bpos DC revealed significantly enriched differentially expressed genes within extracellular matrix degrading enzyme and matrix metalloprotease gene clusters. In contrast, the CD103pos DC subset did not appear to be involved in pulmonary fibrogenesis. CONCLUSIONS: We show that Flt3L protein and numbers of lung DC are upregulated in mice and humans during pulmonary fibrogenesis, and increased mobilisation of lung CD11bpos DC limits the severity of lung fibrosis in mice. The current study helps to inform the development of DC-based immunotherapy as a novel intervention against lung fibrosis in humans.
Asunto(s)
Colágeno/metabolismo , Células Dendríticas/metabolismo , Pulmón/metabolismo , Fibrosis Pulmonar/metabolismo , Tirosina Quinasa 3 Similar a fms/metabolismo , Animales , Células Dendríticas/patología , Modelos Animales de Enfermedad , Ligandos , Pulmón/patología , Proteínas de la Membrana/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
Nasopharyngeal colonization with Streptococcus pneumoniae (the pneumococcus) is known to mount protective adaptive immune responses in rodents and humans. However, the cellular response of the nasopharyngeal compartment to pneumococcal colonization and its importance for the ensuing adaptive immune response is only partially defined. Here we show that nasopharyngeal colonization with S. pneumoniae triggered substantial expansion of both integrin αE (CD103) positive dendritic cells (DC) and T lymphocytes in nasopharynx, nasal-associated lymphoid tissue (NALT) and cervical lymph nodes (CLN) of WT mice. However, nasopharyngeal de-colonization and pneumococcus-specific antibody responses were similar between WT and CD103 KO mice or Batf3 KO mice. Also, naïve WT mice passively immunized with antiserum from previously colonized WT and CD103 KO mice were similarly protected against invasive pneumococcal disease (IPD). In summary, the data show that CD103 is dispensable for pneumococcal colonization-induced adaptive immune responses in mice.
Asunto(s)
Antígenos CD/metabolismo , Células Dendríticas/inmunología , Cadenas alfa de Integrinas/metabolismo , Tejido Linfoide/inmunología , Enfermedades Nasofaríngeas/inmunología , Infecciones Neumocócicas/inmunología , Streptococcus pneumoniae/fisiología , Linfocitos T/inmunología , Inmunidad Adaptativa , Animales , Anticuerpos Antibacterianos/metabolismo , Antígenos CD/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Diferenciación Celular , Células Cultivadas , Modelos Animales de Enfermedad , Femenino , Humanos , Cadenas alfa de Integrinas/genética , Activación de Linfocitos , Tejido Linfoide/virología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas Represoras/genéticaRESUMEN
Nasopharyngeal colonization with Streptococcus pneumoniae (Spn) is an important precondition for the development of pneumococcal pneumonia. At the same time, nasopharyngeal colonization with Spn has been shown to mount adaptive immune responses against Spn in mice and humans. Cellular responses of the nasopharyngeal compartment, including the nasal-associated lymphoid tissue, to pneumococcal colonization and their importance for developing adaptive immune responses are poorly defined. We show that nasopharyngeal colonization with S. pneumoniae led to substantial expansion of dendritic cells (DCs) both in nasopharyngeal tissue and nasal-associated lymphoid tissue of mice. Depletion of DCs achieved by either diphtheria toxin (DT) treatment of chimeric zDC+/DTR mice, or by use of FMS-like tyrosine kinase 3 ligand (Flt3L) KO mice exhibiting congenitally reduced DC pool sizes, significantly diminished antibody responses after colonization with Spn, along with impaired protective immunity against invasive pneumococcal disease. Collectively, the data show that classical DCs contribute to pneumococcal colonization induced adaptive immune responses against invasive pneumococcal disease in two different mouse models. These data may be useful for future nasopharyngeal vaccination strategies against pneumococcal diseases in humans.
Asunto(s)
Células Dendríticas/fisiología , Nasofaringe/inmunología , Neumonía Neumocócica/inmunología , Streptococcus pneumoniae/inmunología , Inmunidad Adaptativa , Animales , Formación de Anticuerpos/genética , Proliferación Celular/genética , Células Cultivadas , Células Dendríticas/microbiología , Femenino , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Nasofaringe/microbiología , Streptococcus pneumoniae/crecimiento & desarrollo , Tirosina Quinasa 3 Similar a fms/genéticaRESUMEN
Among various innate immune receptor families, the role of C-type lectin receptors (CLRs) in lung protective immunity against Streptococcus pneumoniae (S. pneumoniae) is not fully defined. We here show that Mincle gene expression was induced in alveolar macrophages and neutrophils in bronchoalveolar lavage fluids of mice and patients with pneumococcal pneumonia. Moreover, S. pneumoniae directly triggered Mincle reporter cell activation in vitro via its glycolipid glucosyl-diacylglycerol (Glc-DAG), which was identified as the ligand recognized by Mincle. Purified Glc-DAG triggered Mincle reporter cell activation and stimulated inflammatory cytokine release by human alveolar macrophages and alveolar macrophages from WT but not Mincle KO mice. Mincle deficiency led to increased bacterial loads and decreased survival together with strongly dysregulated cytokine responses in mice challenged with focal pneumonia inducing S. pneumoniae, all of which was normalized in Mincle KO mice reconstituted with a WT hematopoietic system. In conclusion, the Mincle-Glc-DAG axis is a hitherto unrecognized element of lung protective immunity against focal pneumonia induced by S. pneumoniae.
Asunto(s)
Glucolípidos/metabolismo , Lectinas Tipo C/inmunología , Macrófagos Alveolares/inmunología , Neumonía Neumocócica/inmunología , Receptores Inmunológicos/inmunología , Streptococcus pneumoniae/inmunología , Animales , Cromatografía Líquida de Alta Presión , Citometría de Flujo , Glucolípidos/inmunología , Humanos , Inmunofenotipificación , Lectinas Tipo C/metabolismo , Proteínas de la Membrana/inmunología , Proteínas de la Membrana/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neutrófilos/inmunología , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores Inmunológicos/metabolismo , Streptococcus pneumoniae/metabolismoRESUMEN
The macrophage-inducible C-type lectin Mincle has recently been identified to be a pattern recognition receptor sensing mycobacterial infection via recognition of the mycobacterial cell wall component trehalose-6',6-dimycolate (TDM). However, its role in systemic mycobacterial infections has not been examined so far. Mincle-knockout (KO) mice were infected intravenously with Mycobacterium bovis BCG to mimic the systemic spread of mycobacteria under defined experimental conditions. After intravenous infection with M. bovis BCG, Mincle-KO mice responded with significantly higher numbers of mycobacterial CFU in spleen and liver, while reduced granuloma formation was observed only in the spleen. At the same time, reduced Th1 cytokine production and decreased numbers of gamma interferon-producing T cells were observed in the spleens of Mincle-KO mice relative to the numbers in the spleens of wild-type (WT) mice. The effect of adoptive transfer of defined WT leukocyte subsets generated from bone marrow cells of zDC(+/DTR) mice (which bear the human diphtheria toxin receptor [DTR] under the control of the classical dendritic cell-specific zinc finger transcription factor zDC) to specifically deplete Mincle-expressing classical dendritic cells (cDCs) but not macrophages after diphtheria toxin application on the numbers of splenic and hepatic CFU and T cell subsets was then determined. Adoptive transfer experiments revealed that Mincle-expressing splenic cDCs rather than Mincle-expressing macrophages contributed to the reconstitution of attenuated splenic antimycobacterial immune responses in Mincle-KO mice after intravenous challenge with BCG. Collectively, we show that expression of Mincle, particularly by cDCs, contributes to the control of splenic M. bovis BCG infection in mice.
Asunto(s)
Células Dendríticas/inmunología , Lectinas Tipo C/metabolismo , Proteínas de la Membrana/metabolismo , Mycobacterium bovis/inmunología , Bazo/microbiología , Tuberculosis/inmunología , Animales , Carga Bacteriana , Proteínas de Transporte de Catión , Recuento de Colonia Microbiana , Citocinas/metabolismo , Modelos Animales de Enfermedad , Granuloma/microbiología , Granuloma/patología , Lectinas Tipo C/deficiencia , Hígado/microbiología , Proteínas de la Membrana/deficiencia , Ratones Endogámicos C57BL , Ratones Noqueados , Bazo/inmunología , Linfocitos T/inmunologíaRESUMEN
RATIONALE: Respiratory tract infections are common in patients suffering from pulmonary fibrosis. The interplay between bacterial infection and fibrosis is characterised poorly. OBJECTIVES: To assess the effect of Gram-positive bacterial infection on fibrosis exacerbation in mice. METHODS: Fibrosis progression in response to Streptococcus pneumoniae was examined in two different mouse models of pulmonary fibrosis. MEASUREMENTS AND MAIN RESULTS: We demonstrate that wild-type mice exposed to adenoviral vector delivery of active transforming growth factor-ß1 (TGFß1) or diphteria toxin (DT) treatment of transgenic mice expressing the DT receptor (DTR) under control of the surfactant protein C (SPC) promoter (SPC-DTR) to induce pulmonary fibrosis developed progressive fibrosis following infection with Spn, without exhibiting impaired lung protective immunity against Spn. Antibiotic treatment abolished infection-induced fibrosis progression. The cytotoxin pneumolysin (Ply) of Spn caused this phenomenon in a TLR4-independent manner, as Spn lacking Ply (SpnΔply) failed to trigger progressive fibrogenesis, whereas purified recombinant Ply did. Progressive fibrogenesis was also observed in AdTGFß1-exposed Ply-challenged TLR4 KO mice. Increased apoptotic cell death of alveolar epithelial cells along with an attenuated intrapulmonary release of antifibrogenic prostaglandin E2 was found to underlie progressive fibrogenesis in Ply-challenged AdTGFß1-exposed mice. Importantly, vaccination of mice with the non-cytotoxic Ply derivative B (PdB) substantially attenuated Ply-induced progression of lung fibrosis in AdTGFß1-exposed mice. CONCLUSIONS: Our data unravel a novel mechanism by which infection with Spn through Ply release induces progression of established lung fibrosis, which can be attenuated by protein-based vaccination of mice.
Asunto(s)
Neumonía Neumocócica/complicaciones , Fibrosis Pulmonar/microbiología , Estreptolisinas/fisiología , Animales , Antibacterianos/uso terapéutico , Apoptosis/efectos de los fármacos , Proteínas Bacterianas/farmacología , Proteínas Bacterianas/fisiología , Líquido del Lavado Bronquioalveolar/inmunología , Toxina Diftérica , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Células Epiteliales/efectos de los fármacos , Femenino , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Vacunas Neumococicas , Neumonía Neumocócica/tratamiento farmacológico , Neumonía Neumocócica/inmunología , Neumonía Neumocócica/metabolismo , Alveolos Pulmonares/efectos de los fármacos , Alveolos Pulmonares/patología , Fibrosis Pulmonar/inmunología , Fibrosis Pulmonar/metabolismo , Fibrosis Pulmonar/prevención & control , Estreptolisinas/deficiencia , Estreptolisinas/farmacología , Factor de Crecimiento Transformador beta1/metabolismoRESUMEN
The role of macrophage-inducible C-type lectin Mincle in lung innate immunity against mycobacterial infection is incompletely defined. In this study, we show that wild-type (WT) mice responded with a delayed Mincle induction on resident alveolar macrophages and newly immigrating exudate macrophages to infection with Mycobacterium bovis bacillus Calmette-Guérin (BCG), peaking by days 14-21 posttreatment. As compared with WT mice, Mincle knockout (KO) mice exhibited decreased proinflammatory mediator responses and leukocyte recruitment upon M. bovis BCG challenge, and they demonstrated increased mycobacterial loads in pulmonary and extrapulmonary organ systems. Secondary mycobacterial infection on day 14 after primary BCG challenge led to increased cytokine gene expression in sorted alveolar macrophages of WT mice, but not Mincle KO mice, resulting in substantially reduced alveolar neutrophil recruitment and increased mycobacterial loads in the lungs of Mincle KO mice. Collectively, these data show that WT mice respond with a relatively late Mincle expression on lung sentinel cells to M. bovis BCG infection. Moreover, M. bovis BCG-induced upregulation of C-type lectin Mincle on professional phagocytes critically shapes antimycobacterial responses in both pulmonary and extrapulmonary organ systems of mice, which may be important for elucidating the role of Mincle in the control of mycobacterial dissemination in mice.
Asunto(s)
Inmunidad Innata , Lectinas Tipo C/fisiología , Macrófagos Alveolares/inmunología , Macrófagos Alveolares/patología , Proteínas de la Membrana/fisiología , Mycobacterium bovis/inmunología , Tuberculosis/inmunología , Tuberculosis/metabolismo , Animales , Inmunidad Innata/genética , Inflamación/inmunología , Inflamación/microbiología , Inflamación/patología , Lectinas Tipo C/biosíntesis , Lectinas Tipo C/deficiencia , Pulmón/inmunología , Pulmón/microbiología , Pulmón/patología , Macrófagos Alveolares/microbiología , Proteínas de la Membrana/biosíntesis , Proteínas de la Membrana/deficiencia , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neutrófilos/inmunología , Neutrófilos/microbiología , Neutrófilos/patología , Transducción de Señal/genética , Transducción de Señal/inmunología , Tuberculosis/prevención & controlRESUMEN
The neutrophil serine proteases cathepsin G (CG) and neutrophil elastase (NE) are involved in immune-regulatory processes and exert antibacterial activity against various pathogens. To date, their role and their therapeutic potential in pulmonary host defense against mycobacterial infections are poorly defined. In this work, we studied the roles of CG and NE in the pulmonary resistance against Mycobacterium bovis bacillus Calmette-Guérin (BCG). CG-deficient mice and even more pronounced CG/NE-deficient mice showed significantly impaired pathogen elimination to infection with M. bovis BCG in comparison to wild-type mice. Moreover, granuloma formation was more pronounced in M. bovis BCG-infected CG/NE-deficient mice in comparison to CG-deficient and wild-type mice. A close examination of professional phagocyte subsets revealed that exclusively neutrophils shuttled CG and NE into the bronchoalveolar space of M. bovis BCG-infected mice. Accordingly, chimeric wild-type mice with a CG/NE-deficient hematopoietic system displayed significantly increased lung bacterial loads in response to M. bovis BCG infection. Therapeutically applied human CG/NE encapsulated in liposomes colocalized with mycobacteria in alveolar macrophages, as assessed by laser scanning and electron microscopy. Importantly, therapy with CG/NE-loaded liposomes significantly reduced mycobacterial loads in the lungs of mice. Together, neutrophil-derived CG and NE critically contribute to deceleration of pathogen replication during the early phase of antimycobacterial responses. In addition, to our knowledge, we show for the first time that liposomal encapsulated CG/NE exhibit therapeutic potential against pulmonary mycobacterial infections. These findings may be relevant for novel adjuvant approaches in the treatment of tuberculosis in humans.
Asunto(s)
Catepsina G/inmunología , Elastasa de Leucocito/inmunología , Macrófagos Alveolares/inmunología , Mycobacterium bovis/inmunología , Tuberculosis Pulmonar/inmunología , Animales , Catepsina G/genética , Catepsina G/metabolismo , Femenino , Humanos , Elastasa de Leucocito/genética , Elastasa de Leucocito/metabolismo , Macrófagos Alveolares/enzimología , Macrófagos Alveolares/microbiología , Ratones , Ratones Mutantes , Tuberculosis Pulmonar/tratamiento farmacológico , Tuberculosis Pulmonar/enzimología , Tuberculosis Pulmonar/microbiologíaRESUMEN
The growth factor GM-CSF has an important role in pulmonary surfactant metabolism and the regulation of antibacterial activities of lung sentinel cells. However, the potential of intra-alveolar GM-CSF to augment lung protective immunity against inhaled bacterial pathogens has not been defined in preclinical infection models. We hypothesized that transient overexpression of GM-CSF in the lungs of mice by adenoviral gene transfer (Ad-GM-CSF) would protect mice from subsequent lethal pneumococcal pneumonia. Our data show that intra-alveolar delivery of Ad-GM-CSF led to sustained increased pSTAT5 expression and PU.1 protein expression in alveolar macrophages during a 28-d observation period. Pulmonary Ad-GM-CSF delivery 2-4 wk prior to infection of mice with Streptococcus pneumoniae significantly reduced mortality rates relative to control vector-treated mice. This increased survival was accompanied by increased inducible NO synthase expression, antibacterial activity, and a significant reduction in caspase-3-dependent apoptosis and secondary necrosis of lung sentinel cells. Importantly, therapeutic treatment of mice with rGM-CSF improved lung protective immunity and accelerated bacterial clearance after pneumococcal challenge. We conclude that prophylactic delivery of GM-CSF triggers long-lasting immunostimulatory effects in the lung in vivo and rescues mice from lethal pneumococcal pneumonia by improving antibacterial immunity. These data support use of novel antibiotic-independent immunostimulatory therapies to protect patients against bacterial pneumonias.
Asunto(s)
Factor Estimulante de Colonias de Granulocitos y Macrófagos/administración & dosificación , Factor Estimulante de Colonias de Granulocitos y Macrófagos/genética , Neumonía Neumocócica/inmunología , Neumonía Neumocócica/prevención & control , Adenoviridae/genética , Animales , Líquido del Lavado Bronquioalveolar/inmunología , Líquido del Lavado Bronquioalveolar/microbiología , Técnicas de Transferencia de Gen , Vectores Genéticos/administración & dosificación , Vectores Genéticos/inmunología , Vectores Genéticos/uso terapéutico , Factor Estimulante de Colonias de Granulocitos y Macrófagos/biosíntesis , Intubación Intratraqueal , Pulmón/inmunología , Pulmón/microbiología , Pulmón/virología , Ratones , Ratones Endogámicos C57BL , Neumonía Neumocócica/mortalidad , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/uso terapéuticoRESUMEN
FMS-like tyrosine kinase-3 ligand (Flt3L) is a dendritic cell (DC) growth and differentiation factor with potential in antitumor therapies and antibacterial immunization strategies. However, the effect of systemic Flt3L treatment on lung-protective immunity against bacterial infection is incompletely defined. Here, we examined the impact of deficient (in Flt3L knockout [KO] mice), normal (in wild-type [WT] mice), or increased Flt3L availability (in WT mice pretreated with Flt3L for 3, 5, or 7 days) on lung DC subset profiles and lung-protective immunity against the major lung-tropic pathogen, Streptococcus pneumoniae. Although in Flt3L-deficient mice the numbers of DCs positive for CD11b (CD11b(pos) DCs) and for CD103 (CD103(pos) DCs) were diminished, lung permeability, a marker of injury, was unaltered in response to S. pneumoniae. In contrast, WT mice pretreated with Flt3L particularly responded with increased numbers of CD11b(pos) DCs and with less pronounced numbers of CD103(pos) DCs and impaired bacterial clearance and with increased lung permeability following S. pneumoniae challenge. Notably, infection of Flt3L-pretreated mice with S. pneumoniae lacking the pore-forming toxin, pneumolysin (PLY), resulted in substantially less lung CD11b(pos) DCs activation and reduced lung permeability. Collectively, this study establishes that Flt3L treatment enhances the accumulation of proinflammatory activated lung CD11b(pos) DCs which contribute to acute lung injury in response to PLY released by S. pneumoniae.
Asunto(s)
Lesión Pulmonar Aguda/inmunología , Células Dendríticas/inmunología , Proteínas de la Membrana/uso terapéutico , Streptococcus pneumoniae/patogenicidad , Estreptolisinas/metabolismo , Lesión Pulmonar Aguda/terapia , Animales , Proteínas Bacterianas/metabolismo , Antígeno CD11b/metabolismo , Células Dendríticas/citología , Células Dendríticas/efectos de los fármacos , Células Dendríticas/patología , Humanos , Inflamación/inmunología , Ligandos , Pulmón/efectos de los fármacos , Pulmón/inmunología , Pulmón/patología , Proteínas de la Membrana/genética , Proteínas de la Membrana/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neumonía Neumocócica/inmunología , Neumonía Neumocócica/microbiología , Neumonía Neumocócica/patologíaRESUMEN
Dendritic cells (DCs) are essential for innate and adaptive immunity, but are purported to exhibit variable radiosensitivity in response to irradiation in various bone marrow transplantation (BMT) protocols. To address this controversy, we analyzed the magnitude of depletion and repopulation of both lung CD11b(pos) DC and CD103(pos) DC subsets in response to irradiation and BMT in a murine model. In our study, CD45.2(pos) donor bone marrow cells were transplanted into irradiated CD45.1(pos) recipient mice to examine the depletion of recipient DC subsets and the repopulation of donor DC subsets. We observed an apoptosis-mediated and necrosis-mediated depletion (> 90%) of the recipient CD103(pos) DC subset, and only a 50-60% depletion of recipient CD11b(pos) DCs from lung parenchymal tissue on Days 3 and 5, whereas recipient alveolar and lung macrophages were much less radiosensitive, showing an approximately 50% depletion by Days 14-21 after treatment. A repopulation of lung tissue with donor DC subsets had occurred by Days 10 and 28 for CD11b(pos) DCs and CD103(pos) DCs, whereas alveolar and lung macrophages were repopulated by 6 and 10 weeks after treatment. Furthermore, the infection of mice with Streptococcus pneumoniae further accelerated the turnover of lung DCs and lung macrophage subsets. Our data illustrate the vulnerability of lung CD103(pos) DCs and CD11b(pos) DCs to irradiation, and indicate that an accelerated turnover of lung DC subsets occurs, relative to pulmonary and lung macrophages. Our findings may have important implications in the development of adjuvant immune-stimulatory protocols that could reduce the risk of opportunistic infections in patients undergoing BMT.
Asunto(s)
Trasplante de Médula Ósea/métodos , Células Dendríticas/citología , Pulmón/patología , Animales , Antígenos CD/biosíntesis , Apoptosis , Antígeno CD11b/biosíntesis , Inmunofenotipificación , Cadenas alfa de Integrinas/biosíntesis , Antígenos Comunes de Leucocito/biosíntesis , Macrófagos/citología , Macrófagos/metabolismo , Ratones , Ratones Endogámicos C57BL , Modelos Biológicos , Necrosis , Streptococcus pneumoniae/metabolismo , Factores de TiempoRESUMEN
The monocyte chemoattractant CCL2 is of major importance in inflammatory monocyte recruitment to the lungs in response to bacterial infection. Streptococcus pneumoniae is the most prevalent pathogen in community-acquired pneumonia causing significant morbidity and mortality worldwide. In the current study, we examined the role of CCL2 in lung-protective immunity against two strains of S. pneumoniae exhibiting different virulence profiles. Both wild-type mice and CCL2 knockout (KO) mice became septic within 24 h of infection with serotype 3 S. pneumoniae and died of infection by day 4 after challenge. In contrast, wild-type mice challenged with serotype 19 S. pneumoniae did not become septic or succumb to pneumococcal pneumonia, whereas CCL2 KO mice showed an early bacterial outgrowth in their lungs and sepsis starting by day 2 after infection, finally resulting in approximately 50% decreased survival compared with wild-type mice. This phenotype was not due to impaired lung neutrophil recruitment in the KO mice, but was characterized by a significantly reduced recruitment of lung exudate macrophages and conventional lung dendritic cells, suggesting that these two phagocyte subsets critically regulate protection against septic disease progression in mice. In conclusion, we show here a differential role for CCL2-dependent lung exudate macrophage and conventional dendritic cell recruitment that critically contributes to lung protective immunity against S. pneumoniae.