cathepsin-g and chymostatin

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

Neutrophils often invade various tumor tissues and affect tumor progression and metastasis. Cathepsin G (CG) is a serine protease secreted from activated neutrophils. Previously, we have shown that CG induces the formation of E-cadherin-mediated multicellular spheroids of human breast cancer MCF-7 cells; however, the molecular mechanisms involved in this process are unknown. In this study, we investigated whether CG required its enzymatic activity to induce MCF-7 cell aggregation. The cell aggregation-inducing activity of CG was inhibited by pretreatment of CG with the serine protease inhibitors chymostatin and phenylmethylsulfonyl fluoride. In addition, an enzymatically inactive S195G (chymotrypsinogen numbering) CG did not induce cell aggregation. Furthermore, CG specifically bound to the cell surface of MCF-7 cells via a catalytic site-independent mechanism because the binding was not affected by pretreatment of CG with serine protease inhibitors, and cell surface binding was also detected with S195G CG. Therefore, we propose that the CG-induced aggregation of MCF-7 cells occurs via a 2-step process, in which CG binds to the cell surface, independently of its catalytic site, and then induces cell aggregation, which is dependent on its enzymatic activity.

Topics: Catalytic Domain; Cathepsin G; Cell Adhesion; Cell Aggregation; Cell Line, Tumor; Humans; Oligopeptides; Phenylmethylsulfonyl Fluoride; Protein Binding

Alternative pathways of angiotensin II biosynthesis play a significant role in the renin-angiotensin system. In this study porcine renal tissue was investigated for angiotensin II-generating enzymes.. Protein extracts from porcine renal tissue were fractionated by liquid chromatography and tested for their angiotensin II-generating activity by the mass-spectrometry-assisted enzyme screening system (MES) and the active fractions were purified to near homogeneity. In one of these active fractions, inhibitable by an angiotensin-converting enzyme specific inhibitor, purified by anion-exchange chromatography, followed by hydroxyapatite chromatography, lectin affinity chromatography, size-exclusion chromatography and two-dimensional electrophoresis, angiotensin-converting enzyme was identified by a tryptic peptide matrix-assisted-laser-desorption/ionization (MALDI) mass fingerprint analysis. In a second active fraction, which was inhibited by chymostatin and antipain, yielded by anion-exchange chromatography, followed by hydroxyapatite chromatography, lectin affinity chromatography, chymostatin-antipain chromatography and one-dimensional electrophoresis, cathepsin G was identified by electro-spray ionization (ESI)-ion-trap mass spectrometry. The angiotensin-generating activities of the fraction containing angiotensin-converting enzyme and the fraction containing cathepsin G were in the same order of magnitude, thus showing that the contribution of cathepsin G towards the production of angiotensin II is significant.. This is the first time that cathepsin G has been identified in mammalian renal tissue.

Topics: Angiotensin II; Animals; Anions; Cathepsin G; Cathepsins; Chromatography, Ion Exchange; Chromatography, Liquid; Durapatite; Kidney; Lectins; Mass Spectrometry; Oligopeptides; Serine Endopeptidases; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Swine

We have isolated a novel soluble factor(s), neutrophil activator of matrix metalloproteinases (NAM), secreted by unstimulated normal human peripheral blood neutrophils that causes the activation of cell secreted promatrix metalloproteinase-2 (proMMP-2). Partially purified preparations of NAM have been isolated from the conditioned media of neutrophils employing gelatin-Sepharose chromatography and differential membrane filter centrifugation. NAM activity, as assessed by exposing primary human umbilical vein endothelial cells (HUVEC) or HT1080 cells to NAM followed by gelatin zymography, was seen within one hour. Tissue inhibitor of metalloproteinase-2 (TIMP-2) and hydroxamic acid derived inhibitors of MMPs (CT1746 and BB94) abrogated the activation of proMMP-2 by NAM, while inhibitors of serine and cysteine proteases showed no effect. NAM also produced an increase in TIMP-2 binding to HUVEC and HT1080 cell surfaces that was inhibited by TIMP-2, CT1746, and BB94. Time-dependent increases in MT1-MMP protein and mRNA were seen following the addition of NAM to cells. These data support a role for NAM in cancer dissemination.

Topics: Adult; Amides; Calcimycin; Cathepsin G; Cathepsins; Cells, Cultured; Culture Media, Conditioned; Endothelium, Vascular; Enzyme Activation; Enzyme Precursors; Humans; Inflammation; Ionomycin; Matrix Metalloproteinase 14; Matrix Metalloproteinase 2; Neoplasm Invasiveness; Neoplasm Metastasis; Neutrophils; Oligopeptides; Pancreatic Elastase; Phenylalanine; Protease Inhibitors; Proteins; RNA, Messenger; Serine Endopeptidases; Substrate Specificity; Tetradecanoylphorbol Acetate; Thiophenes; Tissue Inhibitor of Metalloproteinase-2; Umbilical Veins

We investigated whether vascular smooth muscle cells (VSMC)-derived from human produce angiotensin (Ang) II upon change from the contractile phenotype to the synthetic phenotype by incubation with fibronectin (FN). Expression of alpha-smooth muscle (SM) actin, apparent in the contractile phenotype, was decreased by FN. Expressions of matrix Gla and osteopontin, apparent in the synthetic phenotype, were increased by FN. Ang II measured by radioimmunoassay (RIA) was significantly increased in human VSMC by FN. Expression of mRNAs for Ang II-generating proteases cathepsin D, cathepsin G, ACE, and chymase was increased by FN. Expressions of cathepsin D and cathepsin G proteins were also increased by FN. Ang I-generating activity, which was inhibited by an aspartyl protease inhibitor pepstatin A, was readily detected in the conditioned medium from human VSMC. Antisense oligodeoxynucleotides (ODNs) that hybridize with cathepsin D and cathepsin G significantly inhibited FN-increased Ang II in conditioned medium and cell extracts. In VSMC conditioned medium, FN-induced elevation of Ang II was significantly inhibited by temocapril but not by chymostatin. Ang II type 1 receptor antagonist CV11974 completely, and antisense cathepsin D and cathepsin G ODNs partially inhibited the FN-stimulated growth of human VSMC. These results indicate that the change of homogeneous cultures of human VSMC from the contractile to the synthetic phenotype sequentially increases expression of proteases cathepsin D, cathepsin G, and ACE, production of Ang II and productions of growth factors, culminating in VSMC proliferation. These findings implicate a new mechanism for the pathogenesis of human vascular proliferative diseases.

Topics: Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Cathepsin D; Cathepsin G; Cathepsins; Cell Division; Cells, Cultured; Fibronectins; Humans; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Oligonucleotides, Antisense; Oligopeptides; Phenotype; Serine Endopeptidases; Serine Proteinase Inhibitors; Thiazepines

The CXC chemokine stromal cell-derived factor (SDF)-1 is produced constitutively in different tissues. It is the only known ligand for CXCR4, which is widely expressed in leukocytes and in some tissue cells, and acts as coreceptor for X4 HIV strains. Because of the general interest in the mechanisms that regulate the activity of constitutively expressed chemokines, we have studied the inactivation of SDF-1 in cells that bear CXCR4. Here we show that B lymphocytes, NK cells and, to a lesser extent, T lymphocytes inactivate SDF-1 by N-terminal processing. Inactivation is due to cathepsin G which is associated with the membrane of lymphocytes and rapidly cleaves off five N-terminal residues by acting on the Leu(5)-Ser(6) bond yielding SDF-1(6-67). Processing was observed with intact cells, cell membrane preparations and soluble cathepsin G obtained by extraction of the membranes with Triton X-100. Cathepsin G is released by neutrophils and monocytes and binds on the surface of lymphocytes by an apparently saturable process. Analysis of the product obtained, the time course and the sensitivity to inhibitors shows that cathepsin G is the only protease involved. Conversion of SDF-1 to SDF-1(6-67) was complete within minutes to 1-2 h depending on the enzyme source, and was abrogated by inhibitors of serine proteases and chymostatin. Diprotin A, an inhibitor of dipeptidyl peptidase IV, was without effect. Owing to its availability on the surface of SDF-1-responsive cells and its rapid effect, cathepsin G is likely to play a significant role in down-regulating SDF-1 activity.

Topics: Amino Acid Sequence; B-Lymphocytes; Cathepsin G; Cathepsins; Cells, Cultured; Chemokine CXCL12; Chemokines, CXC; Humans; Killer Cells, Natural; Lymphocytes; Membrane Proteins; Molecular Sequence Data; Oligopeptides; Peptides; Serine Endopeptidases; Serine Proteinase Inhibitors; T-Lymphocytes

Cathepsin G is a serine protease located in the azurophil granules of neutrophils. In this study, we investigated the effect of cathepsin G on the functions of human natural killer (NK) cells in vitro. Cathepsin G enhanced NK cytotoxicity rapidly in a dose-dependent fashion. The ability to augment NK cytotoxicity was markedly reduced in the presence of the inhibitor, phenylmethanesulphonyl fluoride (PMSF) or chymostatin, demonstrating that the proteolytic activity of cathepsin G is essential for the induction of NK cytotoxicity. Granulocyte exocytosis is required for NK cell-dependent target killing. Cathepsin G induced the release of the granule enzyme, N-acetyl-beta-D-glucosaminidase, from human NK cells. Moreover, an increase in the cytosolic-free Ca2+ concentration was observed in NK cells after stimulation with cathepsin G. When human granulocytes were stimulated with cytochalasin B and N-formyl-methionyl-leucyl-phenylalanine (fMLP), cathepsin G was released. The cathepsin G released from granulocytes also caused enhancement of NK cytotoxicity. In the presence of serine protease inhibitor the supernatant including cathepsin G obtained from stimulated granulocytes did not enhance NK cytotoxicity, but the stimulated granulocytes did. Highly purified human NK cells treated with cathepsin G enhanced NK cytotoxicity, but NK-depleted lymphocytes did not, demonstrating that cathepsin G regulates NK cytotoxicity independently of other factors. We have shown recently that human cathepsin G binds to human NK cells. These combined data indicate that cathepsin G released from granulocytes binds to NK cells and augments NK cytotoxicity through its protease activity.

Topics: Calcium; Cathepsin G; Cathepsins; Cytotoxicity, Immunologic; Dose-Response Relationship, Drug; Exocytosis; Granulocytes; Humans; Killer Cells, Natural; Oligopeptides; Serine Endopeptidases; Serine Proteinase Inhibitors; Tosyl Compounds; Tumor Cells, Cultured

High activities of the neutrophil proteases, elastase and cathepsin G, are found in the sputum of patients with cystic fibrosis (CF). Because both proteases have been shown to be potent secretagogues for airway submucosal glands, and because hypersecretion is a characteristic feature of CF, the objective of the present study was to examine whether there is secretagogue activity in CF sputum, and to determine the contribution of neutrophil proteases to the secretagogue activity. Confluent monolayers of cultured bovine tracheal serous cells were pulse-labelled with Na2(35)SO4, incubated with diluted CF sputum supernatants in the presence or absence of different protease inhibitors, and the subsequent release of the radio-labelled macromolecules was measured. CF sputum potently induced secretion concentration-dependently. Addition of the selective neutrophil elastase inhibitor ICI 200,355 inhibited the secretory response to CF sputum supernatant by 89%. Addition of a cathepsin G-inhibitor resulted in further inhibition of the secretory response. Addition of phosphoramidon, a drug known to inhibit Pseudomonas aeruginosa elastase, had no effect. We conclude that CF sputum potently stimulates airway submucosal gland cell secretion. These studies with protease inhibitors suggest that neutrophil proteases account substantially for the secretagogue activity present in CF sputum.

Topics: Adult; Animals; Cathepsin G; Cathepsins; Cattle; Cells, Cultured; Cystic Fibrosis; Exocrine Glands; Glycopeptides; Humans; Leukocyte Elastase; Oligopeptides; Pancreatic Elastase; Protease Inhibitors; Serine Endopeptidases; Sputum; Trachea

Eosinophils contain many cytotoxic mediators including eosinophil peroxidase (EPO) in their granules; on degranulation, these mediators are released by various pathophysiological stimuli, resulting in severe tissue damage. However, little is known about inhibitors of degranulation. Here, we report that eosinophils isolated from patients with bronchial asthma have significant chymotrypsin-like serine protease activity in the high salt extract fraction. The protease partially purified and labeled with [3H]diisopropylfluorophosphate has an apparent molecular mass of 28 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The chymotrypsin-like protease was not immunoreactive with antibodies against chymase and atypical chymase from rat mast cells or with an antibody against cathepsin G from human neutrophils. Studies on the subcellular distribution of the chymotrypsin-like protease indicated that the enzyme is mainly localized with EPO in eosinophil granules. Chymostatin, an inhibitor of the chymotrypsin-like protease(s), but not an inhibitor of other types of proteases, markedly inhibited the EPO release from eosinophils that was induced by immunoglobulin G plus rIL-5 or platelet-activating factor, although it had no effect on the release of EPO induced by the calcium ionophore A23187. These results suggest that proteolytic activation by chymotrypsin-like serine protease(s) in eosinophils plays some role in the process of receptor-mediated EPO release from the granules.

Topics: Affinity Labels; Amino Acid Sequence; Asthma; Cathepsin G; Cathepsins; Cell Compartmentation; Cell Degranulation; Chymases; Cross Reactions; Cytoplasmic Granules; Eosinophil Peroxidase; Eosinophils; Humans; Isoflurophate; Mast Cells; Molecular Sequence Data; Oligopeptides; Peroxidases; Serine Endopeptidases; Serine Proteinase Inhibitors; Trypsin

The microbial, peptide-derived aldehyde chymostatin is a potent, competitive inhibitor of chymotrypsin and cathepsin G: Ki = 4 X 10(-10) and 1.5 X 10(-7) M, respectively. Et is "slow-binding inhibitor" of both proteases and, as such, allows determination of rate constants for its association with and dissociation from these proteases. Inhibition kinetics indicate second-order rate constants for the association of chymostatin with chymotrypsin and cathepsin G of 360,000 and 2000 M-1 S-1, respectively and a first-order rate constant for the dissociation of both protease-chymostatin complexes of approximately 0.0002 s-1. Thus, the extreme difference in potency of chymostatin as an inhibitor of chymotrypsin and cathepsin G originates entirely in Kon. Solvent deuterium isotope effects (SIE) were determined to probe the reaction step that rate limits Kon. For the reaction of chymotrypsin with chymostatin, the SIE for Kon is 1.6 +/- 0.1, while for the reaction of chymotrypsin with the peptide substrates Ala-Ala-Phe-pNA and Suc-Ala-Ala-Pro-Phe-pNA, the SIE's for Kc/Km are 2.8 +/- 0.2 and 1.9 +/- 0.1, respectively. These results suggest that Kon for the association of chymotrypsin with chymostatin is at least partially rate limited by a reaction step involving proton transfer. Combined with results for the inhibition of chymotrypsin by Bz-Phe-H [Kennedy, W.P., & Schultz, R. M. (1979) Biochemistry 18, 349-356], these data suggest a mechanism for inhibition by chymostatin involving the general-base-catalyzed formation of an enzyme-bound hemiacetal, followed by a conformational change of this intermediate that produces the final, stable complex of enzyme and inhibitor.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Cathepsin G; Cathepsins; Chymotrypsin; Kinetics; Molecular Weight; Oligopeptides; Protein Binding; Serine Endopeptidases