cathepsin-g and Acute-Lung-Injury

This study aims to evaluate the role of chymostatin in paraquat-induced acute lung injury. Institute of Cancer Research mice were randomly distributed into the NS, DMSO, chymostatin, paraquat or chymostatin treatment groups. Six mice from each group were intraperitoneally injected with chloral hydrate at 0, 1, 2, 4, 8, 12, 24 and 48 h after treatment administration. Blood samples were collected through cardiac puncture. Lung tissues were stained with haematoxylin and eosin for the observation of lung histology. The degree of pulmonary oedema was determined on the basis of lung wet-to-dry ratio (W/D). The serum activity of cathepsin G was determined through substrate fluorescence assay. The serum levels of endothelial cell-specific molecule-1 (endocan), tumour necrosis factor-a (TNF-a), interleukin-1β (IL-1β), IL-6 and high-mobility group box protein 1 (HMGB1) were determined through enzyme-linked immunosorbent assay. The expression levels of endocan and nuclear NF-κBp65 in the lung were quantified through Western blot. Chymostatin alleviated the pathological changes associated with acute alveolitis in mice; decreased the lung W/D ratio, the activity of cathepsin G and the serum concentrations of TNF-a, IL-1β, IL-6 and HMGB1; and increased the serum concentration of endocan. Western blot results revealed that chymostatin up-regulated endocan expression and down-regulated nuclear NF-κBp65 expression in the lung. Chymostatin reversed the inflammatory effects of paraquat-induced lung injury by inhibiting cathepsin G activity to up-regulate endocan expression and indirectly inhibit NF-κBp65 activity.

Topics: Acute Lung Injury; Animals; Anti-Inflammatory Agents; Cathepsin G; Cytokines; Cytoprotection; Disease Models, Animal; Female; HMGB1 Protein; Inflammation Mediators; Lung; Mice, Inbred ICR; Oligopeptides; Paraquat; Proteoglycans; Pulmonary Edema; Time Factors; Transcription Factor RelA

The balance between neutrophil serine proteases (NSPs) and protease inhibitors (PIs) in the lung is a critical determinant for a number of chronic inflammatory lung diseases such as chronic obstructive pulmonary disease, cystic fibrosis and acute lung injury. During activation at inflammatory sites, excessive release of NSPs such as human neutrophil elastase (HNE), proteinase 3 (Pr3) and cathepsin G (CatG), leads to destruction of the lung matrix and continued propagation of acute inflammation. Under normal conditions, PIs counteract these effects by inactivating NSPs; however, in chronic inflammatory lung diseases, there are insufficient amounts of PIs to mitigate damage. Therapeutic strategies are needed to modulate excessive NSP activity for the clinical management of chronic inflammatory lung diseases. In the study reported here, a panel of N-arylacyl O-sulfonated aminoglycosides was screened to identify inhibitors of the NSPs. Dose-dependent inhibitors for each individual serine protease were identified. Select compounds were found to inhibit multiple NSPs, including one lead structure that is shown to inhibit all three NSPs. Two lead compounds identified during the screen for each individual NSP were further characterized as partial mixed inhibitors of CatG. Concentration-dependent inhibition of protease-mediated detachment of lung epithelial cells is demonstrated.

Topics: Acute Lung Injury; Aminoglycosides; Cathepsin G; Cystic Fibrosis; Humans; Inflammation; Leukocyte Elastase; Myeloblastin; Proteinase Inhibitory Proteins, Secretory; Pulmonary Disease, Chronic Obstructive

Interleukin-33 (IL-33) (NF-HEV) is a chromatin-associated nuclear cytokine from the IL-1 family, which has been linked to important diseases, including asthma, rheumatoid arthritis, ulcerative colitis, and cardiovascular diseases. IL-33 signals through the ST2 receptor and drives cytokine production in type 2 innate lymphoid cells (ILCs) (natural helper cells, nuocytes), T-helper (Th)2 lymphocytes, mast cells, basophils, eosinophils, invariant natural killer T (iNKT), and natural killer (NK) cells. We and others recently reported that, unlike IL-1β and IL-18, full-length IL-33 is biologically active independently of caspase-1 cleavage and that processing by caspases results in IL-33 inactivation. We suggested that IL-33, which is released upon cellular damage, may function as an endogenous danger signal or alarmin, similar to IL-1α or high-mobility group box 1 protein (HMGB1). Here, we investigated the possibility that IL-33 activity may be regulated by proteases released during inflammation. Using a combination of in vitro and in vivo approaches, we demonstrate that neutrophil serine proteases cathepsin G and elastase can cleave full-length human IL-33(1-270) and generate mature forms IL-33(95-270), IL-33(99-270), and IL-33(109-270). These forms are produced by activated human neutrophils ex vivo, are biologically active in vivo, and have a ~10-fold higher activity than full-length IL-33 in cellular assays. Murine IL-33 is also cleaved by neutrophil cathepsin G and elastase, and both full-length and cleaved endogenous IL-33 could be detected in the bronchoalveolar lavage fluid in an in vivo model of acute lung injury associated with neutrophil infiltration. We propose that the inflammatory microenvironment may exacerbate disease-associated functions of IL-33 through the generation of highly active mature forms.

Topics: Acute Lung Injury; Animals; Bronchoalveolar Lavage Fluid; Cathepsin G; Electrophoresis, Polyacrylamide Gel; Female; Humans; Interleukin-33; Interleukins; Leukocyte Elastase; Mice; Mice, Inbred BALB C; Neutrophil Activation; Neutrophils; Protein Processing, Post-Translational

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) is an early characteristic of multiple organ dysfunction, responsible for high mortality and poor prognosis in patients. The present study aims to evaluate therapeutic effects and mechanisms of pyrrolidine dithiocarbamate (PDTC) on ALI.. Alveolar-arterial oxygen difference, lung tissue edema and compromise, NF-κB activation in polymorphonuclear neutrophil (PMN), and systemic levels of tumor necrosis factor-alpha (TNFa) and intercellular adhesion molecule-1 (ICAM-1) in rabbits induced by the intravenous administration of lipopolysaccharide (LPS) and treated with PDTC. Production of TNFa and IL-8, activation of Cathepsin G, and PMNs adhesion were also measured.. The intravenous administration of PDTC had partial therapeutic effects on endotoxemia-induced lung tissue edema and damage, neutrophil influx to the lung, alveolar-capillary barrier dysfunction, and high systemic levels of TNFa and ICAM-1 as well as over-activation of NF-κB. PDTC could directly and partially inhibit LPS-induced TNFa hyper-production and over-activities of Cathepsin G. Such inhibitory effects of PDTC were related to the various stimuli and enhanced through combination with PI3K inhibitor.. NF-κB signal pathway could be one of targeting molecules and the combination with other signal pathway inhibitors may be an alternative of therapeutic strategies for ALI/ARDS.

Topics: Acute Lung Injury; Animals; Capillaries; Cathepsin G; Cell Adhesion; Cells, Cultured; Female; Intercellular Adhesion Molecule-1; Lung; Male; Neutrophils; NF-kappa B; Organ Size; Oxygen; Pulmonary Alveoli; Pyrrolidines; Rabbits; Subcellular Fractions; Thiocarbamates; Tumor Necrosis Factor-alpha