cathepsin-g and Pneumonia

Inflammation is an essential process in many pulmonary diseases in which kinins are generated by protease action on kininogen, a phenomenon that is blocked by protease inhibitors. We evaluated kinin release in an

Topics: Animals; Caesalpinia; Cathepsin G; Disease Models, Animal; Kininogens; Models, Biological; Neutrophils; Phytochemicals; Plasma Kallikrein; Pneumonia; Protease Inhibitors; Rats; Seeds

Current treatments for inflammation associated with bronchopulmonary dysplasia (BPD) fail to show clinical efficacy. Foxm1, a transcription factor of the Forkhead box family, is a critical mediator of lung development and carcinogenesis, but its role in BPD-associated pulmonary inflammation is unknown. Immunohistochemistry and RNA analysis were used to assess Foxm1 in lung tissue from hyperoxia-treated mice and patients with BPD. LysM-Cre/Foxm1(-/-) mice, in which Foxm1 was deleted from myeloid-derived inflammatory cells, including macrophages, monocytes, and neutrophils, were exposed to neonatal hyperoxia, causing lung injury and remodeling. Measurements of lung function and flow cytometry were used to evaluate the effects of Foxm1 deletion on pulmonary inflammation and repair. Increased Foxm1 expression was observed in pulmonary macrophages of hyperoxia-exposed mice and in lung tissue from patients with BPD. After hyperoxia, deletion of Foxm1 from the myeloid cell lineage decreased numbers of interstitial macrophages (CD45(+)CD11b(+)Ly6C(-)Ly6G(-)F4/80(+)CD68(-)) and impaired alveologenesis and lung function. The exaggerated BPD-like phenotype observed in hyperoxia-exposed LysM-Cre/Foxm1(-/-) mice was associated with increased expression of neutrophil-derived myeloperoxidase, proteinase 3, and cathepsin g, all of which are critical for lung remodeling and inflammation. Our data demonstrate that Foxm1 influences pulmonary inflammatory responses to hyperoxia, inhibiting neutrophil-derived enzymes and enhancing monocytic responses that limit alveolar injury and remodeling in neonatal lungs.

Topics: Airway Remodeling; Alveolar Epithelial Cells; Animals; Bronchopulmonary Dysplasia; Case-Control Studies; Cathepsin G; Disease Models, Animal; Forkhead Box Protein M1; Forkhead Transcription Factors; Humans; Hyperoxia; Infant, Newborn; Lung; Lung Injury; Macrophages; Mice, Knockout; Myeloblastin; Neutrophils; Peroxidase; Pneumonia

Inflammation is inextricably associated with primary tumor progression. However, the contribution of inflammation to tumor outgrowth in metastatic organs has remained underexplored. Here, we show that extrinsic inflammation in the lungs leads to the recruitment of bone marrow-derived neutrophils, which degranulate azurophilic granules to release the Ser proteases, elastase and cathepsin G, resulting in the proteolytic destruction of the antitumorigenic factor thrombospondin-1 (Tsp-1). Genetic ablation of these neutrophil proteases protected Tsp-1 from degradation and suppressed lung metastasis. These results provide mechanistic insights into the contribution of inflammatory neutrophils to metastasis and highlight the unique neutrophil protease-Tsp-1 axis as a potential antimetastatic therapeutic target.

Topics: Animals; Blotting, Western; Bone Marrow Transplantation; Cathepsin G; Cell Line, Tumor; Female; Flow Cytometry; Gene Expression; Leukocyte Elastase; Lipopolysaccharides; Lung Neoplasms; Mice, Inbred C57BL; Mice, Knockout; Neoplasms, Experimental; Neutrophils; Peptide Hydrolases; Pneumonia; Proteolysis; Reverse Transcriptase Polymerase Chain Reaction; Serine Proteases; Thrombospondin 1

Phospholipid transfer protein (PLTP) regulates phospholipid transport in the circulation and is highly expressed within the lung epithelium, where it is secreted into the alveolar space. Since PLTP expression is increased in chronic obstructive pulmonary disease (COPD), this study aimed to determine how PLTP affects lung signaling and inflammation. Despite its increased expression, PLTP activity decreased by 80% in COPD bronchoalveolar lavage fluid (BALF) due to serine protease cleavage, primarily by cathepsin G. Likewise, PLTP BALF activity levels decreased by 20 and 40% in smoke-exposed mice and in the media of smoke-treated small airway epithelial (SAE) cells, respectively. To assess how PLTP affected inflammatory responses in a lung injury model, PLTP siRNA or recombinant protein was administered to the lungs of mice prior to LPS challenge. Silencing PLTP at baseline caused a 68% increase in inflammatory cell infiltration, a 120 and 340% increase in ERK and NF-κB activation, and increased MMP-9, IL1β, and IFN-γ levels after LPS treatment by 39, 140, and 190%, respectively. Conversely, PLTP protein administration countered these effects in this model. Thus, these findings establish a novel anti-inflammatory function of PLTP in the lung and suggest that proteolytic cleavage of PLTP by cathepsin G may enhance the injurious inflammatory responses that occur in COPD.

Topics: Aged; Animals; Bronchoalveolar Lavage Fluid; Cathepsin G; Cells, Cultured; Epithelial Cells; Female; Humans; Inflammation; Interferon-gamma; Interleukin-1beta; Lipopolysaccharides; Lung; Male; Matrix Metalloproteinase 9; Mice; Middle Aged; NF-kappa B; Phospholipid Transfer Proteins; Pneumonia; Pulmonary Disease, Chronic Obstructive; Recombinant Proteins; RNA, Small Interfering; Signal Transduction; Smoking

The biological functions of human neutrophil proteinase 3 (PR3) remain unclear because of its close structural resemblance to neutrophil elastase and its apparent functional redundancy with the latter. Thus, all natural inhibitors of PR3 preferentially target neutrophil elastase. We have designed a selective PR3 inhibitor based on the sequence of one of its specific, sensitive FRET substrates. This azapeptide, azapro-3, inhibits free PR3 in solution, PR3 bound to neutrophil membranes, and the PR3 found in crude lung secretions from patients with chronic inflammatory pulmonary diseases. But it does not inhibit significantly neutrophil elastase or cathepsin G. Unlike most of azapeptides, this inhibitor does not form a stable acyl-enzyme complex; it is a reversible competitive inhibitor with a K(i) comparable to the K(m) of the parent substrate. Low concentrations (60 μM) of azapro-3 totally inhibited the PR3 secreted by triggered human neutrophils (200,000 cells/100 μL) and the PR3 in neutrophil homogenates and in lung secretions of patients with lung inflammation for hours. Azapro-3 also resisted proteolysis by all proteases contained in these samples for at least 2h.

Topics: Amino Acid Sequence; Cathepsin G; Chromatography, High Pressure Liquid; Drug Design; Flow Cytometry; Fluorescence Resonance Energy Transfer; Humans; Kinetics; Leukocyte Elastase; Molecular Sequence Data; Myeloblastin; Neutrophils; Oligopeptides; Peptides; Pneumonia; Protein Binding; Proteinase Inhibitory Proteins, Secretory; Proteolysis; Sputum; Substrate Specificity; Time Factors