RESUMO
Introduction: The pathogenesis of chronic lung diseases is multifaceted with a major role of recurrent micro-injuries of the epithelium. While several reports clearly indicated a prominent role for surfactant-producing alveolar epithelial type 2 (AT2) cells, the contribution of gas exchange-permissive alveolar epithelial type 1 (AT1) cells has not been addressed yet. Here, we investigated whether repeated injury of AT1 cells leads to inflammation and interstitial fibrosis. Methods: We chose an inducible model of AT1 cell depletion following local diphtheria toxin (DT) administration using an iDTR flox/flox (idTRfl/fl) X Aquaporin 5CRE (Aqp5CRE) transgenic mouse strain. Results: We investigated repeated doses and intervals of DT to induce cell death of AT1 cells causing inflammation and interstitial fibrosis. We found that repeated DT administrations at 1ng in iDTRfl/fl X Aqp5CRE mice cause AT1 cell death leading to inflammation, increased tissue repair markers and interstitial pulmonary fibrosis. Discussion: Together, we demonstrate that depletion of AT1 cells using repeated injury represents a novel approach to investigate chronic lung inflammatory diseases and to identify new therapeutic targets.
Assuntos
Pneumonia , Relesões , Camundongos , Animais , Camundongos Transgênicos , Inflamação , Fibrose , Morte CelularRESUMO
Chronic obstructive pulmonary disease (COPD) is a major health issue primarily caused by cigarette smoke (CS) and characterized by breathlessness and repeated airway inflammation. NLRP6 is a cytosolic innate receptor controlling intestinal inflammation and orchestrating the colonic host-microbial interface. However, its roles in the lungs remain largely unexplored. Using CS exposure models, our data show that airway inflammation is strongly impaired in Nlrp6-deficient mice with drastically fewer recruited neutrophils, a key cell subset in inflammation and COPD. We found that NLRP6 expression in lung epithelial cells is important to control airway and lung tissue inflammation in an inflammasome-dependent manner. Since gut-derived metabolites regulate NLRP6 inflammasome activation in intestinal epithelial cells, we investigated the link between NLRP6, CS-driven lung inflammation, and gut microbiota composition. We report that acute CS exposure alters gut microbiota in both wild-type (WT) and Nlrp6-deficient mice and that antibiotic treatment decreases CS-induced lung inflammation. In addition, gut microbiota transfer from dysbiotic Nlrp6-deficient mice to WT mice decreased airway lung inflammation in WT mice, highlighting an NLRP6-dependent gut-to-lung axis controlling pulmonary inflammation.
Assuntos
Microbioma Gastrointestinal , Pneumonia , Receptores de Superfície Celular , Poluição por Fumaça de Tabaco , Receptores de Superfície Celular/deficiência , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Pneumonia/induzido quimicamente , Pneumonia/genética , Pneumonia/microbiologia , Animais , Camundongos , Camundongos Endogâmicos C57BL , Células Cultivadas , Células Epiteliais/citologia , Células Epiteliais/patologia , Fezes/microbiologia , Bactérias/classificação , Bactérias/metabolismo , Biodiversidade , Expressão GênicaRESUMO
Chronic pulmonary inflammation and chronic obstructive pulmonary disease (COPD) are major health issues largely due to air pollution and cigarette smoke (CS) exposure. The role of the innate receptor NLRP3 (nucleotide-binding domain and leucine-rich repeat containing protein 3) orchestrating inflammation through formation of an inflammasome complex in CS-induced inflammation or COPD remains controversial. Using acute and subchronic CS exposure models, we found that Nlrp3-deficient mice or wild-type mice treated with the NLRP3 inhibitor MCC950 presented an important reduction of inflammatory cells recruited into the bronchoalveolar space and of pulmonary inflammation with decreased chemokines and cytokines production, in particular IL-1ß demonstrating the key role of NLRP3. Furthermore, mice deficient for Caspase-1/Caspase-11 presented also decreased inflammation parameters, suggesting a role for the NLRP3 inflammasome. Importantly we showed that acute CS-exposure promotes NLRP3-dependent cleavage of gasdermin D in macrophages present in the bronchoalveolar space and in bronchial airway epithelial cells. Finally, Gsdmd-deficiency reduced acute CS-induced lung and bronchoalveolar space inflammation and IL-1ß secretion. Thus, we demonstrated in our model that NLRP3 and gasdermin D are key players in CS-induced pulmonary inflammation and IL-1ß release potentially through gasdermin D forming-pore and/or pyroptoctic cell death.
Assuntos
Fumar Cigarros , Pneumonia , Doença Pulmonar Obstrutiva Crônica , Animais , Caspase 1/metabolismo , Fumar Cigarros/efeitos adversos , Células Epiteliais/metabolismo , Inflamassomos/metabolismo , Inflamação/metabolismo , Macrófagos/metabolismo , Camundongos , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Pneumonia/metabolismo , Doença Pulmonar Obstrutiva Crônica/metabolismo , Nicotiana/metabolismoRESUMO
Cystic fibrosis is associated with chronic Pseudomonas aeruginosa colonization and inflammation. The role of MyD88, the shared adapter protein of the proinflammatory TLR and IL-1R families, in chronic P. aeruginosa biofilm lung infection is unknown. We report that chronic lung infection with the clinical P. aeruginosa RP73 strain is associated with uncontrolled lung infection in complete MyD88-deficient mice with epithelial damage, inflammation, and rapid death. Then, we investigated whether alveolar or myeloid cells contribute to heightened sensitivity to infection. Using cell-specific, MyD88-deficient mice, we uncover that the MyD88 pathway in myeloid or alveolar epithelial cells is dispensable, suggesting that other cell types may control the high sensitivity of MyD88-deficient mice. By contrast, IL-1R1-deficient mice control chronic P. aeruginosa RP73 infection and IL-1ß Ab blockade did not reduce host resistance. Therefore, the IL-1R1/MyD88 pathway is not involved, but other IL-1R or TLR family members need to be investigated. Our data strongly suggest that IL-1 targeted neutralizing therapies used to treat inflammatory diseases in patients unlikely reduce host resistance to chronic P. aeruginosa infection.
Assuntos
Interleucina-1beta/imunologia , Infecções por Pseudomonas/imunologia , Pseudomonas aeruginosa/imunologia , Receptores Tipo I de Interleucina-1/imunologia , Animais , Humanos , Imunidade Inata , Interleucina-1beta/genética , Pulmão/imunologia , Pulmão/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/imunologia , Infecções por Pseudomonas/metabolismo , Receptores Tipo I de Interleucina-1/genética , Transdução de Sinais , Receptores Toll-Like/imunologiaRESUMO
Idiopathic pulmonary fibrosis (IPF) is the most common and severe type of interstitial lung disease for which current treatments display limited efficacy. IPF is largely driven by host-derived danger signals released upon recurrent local tissue damage. Here we explored the roles of self-DNA and stimulator of interferon genes (STING), a protein belonging to an intracellular DNA sensing pathway that leads to type I and/or type III interferon (IFN) production upon activation. Using a mouse model of IPF, we report that STING deficiency leads to exacerbated pulmonary fibrosis with increased collagen deposition in the lungs and excessive remodeling factors expression. We further show that STING-mediated protection does not rely on type I IFN signaling nor on IL-17A or TGF-ß modulation but is associated with dysregulated neutrophils. Together, our data support an unprecedented immunoregulatory function of STING in lung fibrosis.
Assuntos
Fibrose Pulmonar Idiopática/imunologia , Proteínas de Membrana/imunologia , Animais , Bleomicina , Líquido da Lavagem Broncoalveolar/citologia , Líquido da Lavagem Broncoalveolar/imunologia , Colágeno/metabolismo , Modelos Animais de Doenças , Fibrose Pulmonar Idiopática/induzido quimicamente , Fibrose Pulmonar Idiopática/metabolismo , Fibrose Pulmonar Idiopática/patologia , Pulmão/imunologia , Pulmão/metabolismo , Pulmão/patologia , Masculino , Proteínas de Membrana/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ácidos Nucleicos , Nucleotidiltransferases/genética , Receptor de Interferon alfa e beta/genéticaRESUMO
Cigarette smoke (CS) is the major cause of chronic lung injuries, such as chronic obstructive pulmonary disease (COPD). In patients with severe COPD, tertiary lymphoid follicles containing B lymphocytes and B cell-activating factor (BAFF) overexpression are associated with disease severity. In addition, BAFF promotes adaptive immunity in smokers and mice chronically exposed to CS. However, the role of BAFF in the early phase of innate immunity has never been investigated. We acutely exposed C57BL/6J mice to CS and show early BAFF expression in the bronchoalveolar space and lung tissue that correlates to airway neutrophil and macrophage influx. Immunostaining analysis revealed that neutrophils are the major source of BAFF. We confirmed in vitro that neutrophils secrete BAFF in response to cigarette smoke extract (CSE) stimulation. Antibody-mediated neutrophil depletion significantly dampens lung inflammation to CS exposure but only partially decreases BAFF expression in lung tissue and bronchoalveolar space suggesting additional sources of BAFF. Importantly, BAFF deficient mice displayed decreased airway neutrophil recruiting chemokines and neutrophil influx while the addition of exogenous BAFF significantly enhanced this CS-induced neutrophilic inflammation. This demonstrates that BAFF is a key proinflammatory cytokine and that innate immune cells in particular neutrophils, are an unconsidered source of BAFF in early stages of CS-induced innate immunity.
Assuntos
Fator Ativador de Células B/biossíntese , Exposição por Inalação/efeitos adversos , Neutrófilos/imunologia , Neutrófilos/metabolismo , Pneumonia/etiologia , Pneumonia/metabolismo , Poluição por Fumaça de Tabaco/efeitos adversos , Animais , Fator Ativador de Células B/genética , Líquido da Lavagem Broncoalveolar/imunologia , Citocinas/metabolismo , Modelos Animais de Doenças , Suscetibilidade a Doenças , Expressão Gênica , Humanos , Mediadores da Inflamação/metabolismo , Masculino , Camundongos , Infiltração de Neutrófilos , Pneumonia/patologia , Mucosa Respiratória/imunologia , Mucosa Respiratória/metabolismo , Mucosa Respiratória/patologia , Fumar Tabaco/efeitos adversosRESUMO
Cigarette smoke exposure is a leading cause of chronic obstructive pulmonary disease (COPD), a major health issue characterized by airway inflammation with fibrosis and emphysema. Here we demonstrate that acute exposure to cigarette smoke causes respiratory barrier damage with the release of self-dsDNA in mice. This triggers the DNA sensor cGAS (cyclic GMP-AMP synthase) and stimulator of interferon genes (STING), driving type I interferon (IFN I) dependent lung inflammation, which are attenuated in cGAS, STING or type I interferon receptor (IFNAR) deficient mice. Therefore, we demonstrate a critical role of self-dsDNA release and of the cGAS-STING-type I interferon pathway upon cigarette smoke-induced damage, which may lead to therapeutic targets in COPD.
Assuntos
DNA/metabolismo , Proteínas de Membrana/metabolismo , Nucleotidiltransferases/metabolismo , Pneumonia/metabolismo , Enfisema Pulmonar/metabolismo , Receptor de Interferon alfa e beta/metabolismo , Poluição por Fumaça de Tabaco/efeitos adversos , Animais , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Sequências Repetitivas de Ácido NucleicoRESUMO
In addition to the recombinase Rad51, vertebrates have five paralogs of Rad51, all members of the Rad51-dependent recombination pathway. These paralogs form two complexes (Rad51C/Xrcc3 and Rad51B/C/D/Xrcc2), which play roles in somatic recombination, DNA repair and chromosome stability. However, little is known of their possible involvement in meiosis, due to the inviability of the corresponding knockout mice. We have recently reported that the Arabidopsis homolog of one of these Rad51 paralogs (AtXrcc3) is involved in DNA repair and meiotic recombination and present here Arabidopsis lines carrying mutations in three other Rad51 paralogs (AtRad51B, AtRad51C and AtXrcc2). Disruption of any one of these paralogs confers hypersensitivity to the DNA cross-linking agent Mitomycin C, but not to gamma-irradiation. Moreover, the atrad51c-1 mutant is the only one of these to show meiotic defects similar to those of the atxrcc3 mutant, and thus only the Rad51C/Xrcc3 complex is required to achieve meiosis. These results support conservation of functions of the Rad51 paralogs between vertebrates and plants and differing requirements for the Rad51 paralogs in meiosis and DNA repair.