Leukocyte Elastase Inhibitor Research Articles

Serpin B1 protects colonic epithelial cell via blockage of neutrophil elastase activity and its expression is enhanced in patients with ulcerative colitis

Serpin B1 is a monocyte neutrophil elastase (NE) inhibitor and is one of the most efficient inhibitors of NE. In the present study, we investigated the role of serpin B1 in the pathogenesis of ulcerative colitis by using clinical samples and an experimental model. The colonic expression of serpin B1 was determined by real-time polymerase chain reaction (PCR), Western blot analysis, and immunohistological studies in both normal and inflamed mucosa from patients with ulcerative colitis. Serpin B1 mRNA expression was determined by real-time PCR in the mouse dextran sodium sulfate (DSS)-induced colitis model. Young adult mouse colonic epithelial (YAMC) cells were used to determine the role of serpin B1. Serpin B1 gene transfected YAMC cells were treated with H(2)O(2) to measure cell viability. The expression of NE was determined in YAMC cells treated with H(2)O(2). NE-silenced YAMC cells were also treated with H(2)O(2) and then measured for viability. Upregulated expression of serpin B1 in colonic mucosa was confirmed from patients with active ulcerative colitis. Immunohistochemical studies showed that serpin B1 expression was localized not only in inflammatory infiltration cells but also in epithelial cells. Serpin B1 mRNA expression was also increased in colonic mucosa of mouse DSS-induced colitis. Serpin B1-transfected YAMC cells were resistant against the treatment of H(2)O(2). H(2)O(2) treatment significantly induced NE in YAMC cells, and NE-silenced YAMC cells were also resistant against the treatment of H(2)O(2). These results suggest that serpin B1 may be a novel marker of active ulcerative colitis and may play an important role in the pathogenesis of inflammatory bowel disease.

The effect of the neutrophil elastase inhibitor sivelestat on early injury after liver resection.

The effects of sivelestat on endotoxin-induced lung injury, postperfusion lung injury, and ischemia-reperfusion are known, yet the benefits of sivelestat during liver surgery have yet to be elucidated. The aim of the present study was to assess the effects of sivelestat, with a focus on postoperative chemical data, in hepatectomized patients. A prospective clinical study was conducted in 50 patients undergoing hepatic resection. Patients were randomly assigned to receive Elaspol, sivelestat (ELP group, n = 25) or placebo (control group, n = 25). Perioperative blood chemistry values in both groups, including high-mobility group box 1 (HMGB1) and interleukin (IL)-6, were monitored. The HMGB1 levels increased immediately after the operation (from the intraoperative period to the second postoperative day [POD]) in the control group. Compared to the control group, the levels of HMGB1 in the ELP group were significantly suppressed by the perioperative administration of sivelestat. At POD 1, the levels of IL-6 in the ELP group decreased more rapidly than those before the operation compared to the control group. A human clinical study demonstrated the effect of polymorphonuclear leukocyte elastase inhibitor on the earliest markers of liver injury. The present study showed that patients who received sivelestat had reduced release of HMGB1, and that IL-6 levels decreased more rapidly in patients treated with sivelestat than in those who received the placebo. The most appropriate dose, timing, and duration of sivelestat in humans remain unclear; however, it may have therapeutic potential for various liver injuries.

Decreased lung hyaluronan in a model of ARDS in the rat: Effect of an inhibitor of leukocyte elastase

Background. Hyaluronan (HA) is a component of the extracellular matrix in lung tissue and is normally present at low concentrations in blood. HA is rapidly cleared from blood by the liver. Increased concentrations of plasma HA have been found in patients with acute respiratory distress syndrome (ARDS). We investigated changes in HA levels in plasma, bronchoalveolar lavage fluid (BALF), and lung, and their relationship to pretreatment with a leukocyte elastase inhibitor in a rat model of ARDS.Methods. Rats were randomly assigned to three groups: control, thrombin, and thrombin plus elastase inhibitor. By use of a radiometric assay, HA was measured in lungs, BALF, and plasma. Tissue samples from the lungs were stained for HA and examined microscopically. Liver circulation and cardiac output were monitored using radiolabeled microspheres.Results. Infusion of thrombin produced a pronounced increase in wet weight to dry weight ratio, and relative lung water content. This increase was blunted by a leukocyte elastase inhibitor. A decrease in lung HA and increases in both BALF and plasma HA were found. The leukocyte elastase inhibitor counteracted not only the decrease in lung tissue HA, but also the increase in plasma HA. Histologically, there was decreased HA-staining of peribronchial and perivascular areas in the injured rat lung. Decreased liver perfusion was observed after infusion of thrombin.Conclusions. The decrease in lung HA may be involved in the development of pulmonary edema in this ARDS model, and leukocyte elastase may be one cause of this decrease. In addition, an elevated plasma HA level may be an indicator of lung injury.

Enantioselective allylation of imines catalyzed by newly developed (−)-β-pinene-based π-allylpalladium catalyst: an efficient synthesis of (R)-α-propylpiperonylamine and (R)-pipecolic acid

A newly developed π-allylpalladium with a (-)-β-pinene framework and an isobutyl side chain catalyzed the enantioselective allylation of imines in good yields and enantioselectivities (20 examples, up to 98% ee). An efficient enantioselective synthesis of the (R)-α-propyl piperonylamine part of DMP 777, a human leukocyte elastase inhibitor and (R)-pipecolic acid have been achieved as a useful application of this methodology.

1H-pyrazolo[2,3-d][1,2,4]triazine-3,7-diones as a new class of human leukocyte elastase inhibitors.

A novel series of 1H-2-phenyl-substituted-pyrazolo[2,3-d][1,2,4]triazine-3,7-diones (3a-g) as potential inhibitors of Human Leukocyte Elastase (HLE) are reported, the acyl-pyrazole being probably involved in the inhibition mechanism of the serino-protease enzymes. The most potent inhibitor both in vivo and in vitro was 2-o-methoxyphenyl-5-methyl-6-nitro-pyrazolo[2,3-d][1,2,4]triazine-3,7-di one (3e), which significantly suppressed the HLE-induced pulmonary injury in rats when administered orally (100 mg/kg, 3 h prior to HLE administration.

Identification and verification of heat shock protein 60 as a potential serum marker for colorectal cancer

Colorectal cancer (CRC) is a major public health issue worldwide, and novel tumor markers may contribute to its efficient management by helping in early detection, prognosis or surveillance of disease. The aim of our study was to identify new serum biomarkers for CRC, and we followed a phased biomarker discovery and validation process to obtain an accurate preliminary assessment of potential clinical utility. We compared colonic tumors and matched normal tissue from 15 CRC patients, using two-dimensional difference gel electrophoresis (2D-DIGE), and identified 17 proteins that had significant differential expression. These results were further confirmed by western blotting for heat shock protein (HSP) 60, glutathione-S-transferase Pi, α-enolase, T-complex protein 1 subunit β, and leukocyte elastase inhibitor, and by immunohistochemistry for HSP60. Using mAbs raised against HSP60, we developed a reliable (precision of 5–15%) and sensitive (0.3 ng·mL−1) immunoassay for the detection of HSP60 in serum. Elevated levels of HSP60 were found in serum from CRC patients in two independent cohorts; the receiver-operating characteristic curve obtained in 112 patients with CRC and 90 healthy controls had an area under the curve (AUC) of 0.70, which was identical to the AUC of carcinoembryonic antigen. Combination of serum markers improved clinical performance: the AUC of a three-marker logistic regression model combining HSP60, carcinoembryonic antigen and carbohydrate antigen 19-9 reached 0.77. Serum HSP60 appeared to be more specific for late-stage CRC; therefore, future studies should evaluate its utility for determining prognosis or monitoring therapy rather than early detection.

Optimization research on <I>in vitro</I> screening model for human leukocyte elastase inhibitor

Optimization research on <I>in vitro</I> screening model for human leukocyte elastase inhibitor

ChemInform Abstract: Synthesis of Novel Cephem 4-Ketones. A New Series of Human Leukocyte Elastase Inhibitors.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis, stability, biochemical and pharmacokinetic properties of a new potent and selective 4-oxo-β-lactam inhibitor of human leukocyte elastase

The 4-oxo-β-lactams (azetidine-2,4-diones) are potent acylating agents of the human leukocyte elastase (HLE), a neutrophil serine protease that plays a key role in several inflammatory diseases. A novel 4-oxo-β-lactam containing a N-(4-(phenylsulphonylmethyl)phenyl) group, 3, was designed as a potential mechanism-based inhibitor capable of undergoing elimination of phenylsulphinate upon Ser-195 acylation. Compound 3 was found to be a potent slow-tight binding inhibitor of HLE, presenting a remarkable second-order rate constant of 1.46 × 106 M−1s−1 and displaying selectivity over the proteinase 3 and cathepsin G. However, liberation of phenylsulphinate was not observed in the hydrolysis of 3 in both pH 7.4 phosphate buffer and human plasma. The Cmax values of 1207 μg/total blood, 179 μg/g spleen and 106 μg/g lung were determined by HPLC, following a single 30 mg/kg dose of 3 given intraperitoneally to NMRI mice, suggesting that the inhibitor distributes well into tissues. Although being a powerful selective inhibitor of HLE, 4-oxo-β-lactam 3 has a limited stability, being susceptible to off-target reactions (plasma and liver enzymes).

ChemInform Abstract: 1H-Pyrazolo[2,3-d][1,2,4]triazine-3,7-diones as a New Class of Human Leukocyte Elastase Inhibitors.

A novel series of 1H-2-phenyl-substituted-pyrazolo[2,3-d][1,2,4]triazine-3,7-diones (3a-g) as potential inhibitors of Human Leukocyte Elastase (HLE) are reported, the acyl-pyrazole being probably involved in the inhibition mechanism of the serino-protease enzymes. The most potent inhibitor both in vivo and in vitro was 2-o-methoxyphenyl-5-methyl-6-nitro-pyrazolo[2,3-d][1,2,4]triazine-3,7-di one (3e), which significantly suppressed the HLE-induced pulmonary injury in rats when administered orally (100 mg/kg, 3 h prior to HLE administration.

Leukocyte Elastase Inhibitor

Poly(ADP-ribose) polymerase-1 (PARP-1) uses NAD(+) as a substrate to form ADP-ribose. During apoptosis, caspases cleave PARP-1 to avoid excessive NAD consumption. Because PARP-1 is a key regulator of the activity of DNases involved in caspase-dependent apoptosis, its cleavage is required to promote DNA degradation. To explore the situation in caspase-independent cell death, we investigated the effect of PARP-1 on the acid endonuclease leukocyte elastase inhibitor (LEI)-derived DNase II (L-DNase II). We found for the first time an association between PARP-1 and LEI/L-DNase II. Unexpectedly, we observed that LEI influenced the automodification of PARP-1.

Activity‐based mass spectrometric characterization of proteases and inhibitors in human saliva

Proteases present in oral fluid effectively modulate the structure and function of some salivary proteins and have been implicated in tissue destruction in oral disease. To identify the proteases operating in the oral environment, proteins in pooled whole saliva supernatant were separated by anion-exchange chromatography and individual fractions were analyzed for proteolytic activity by zymography using salivary histatins as the enzyme substrates. Protein bands displaying proteolytic activity were particularly prominent in the 50-75 kDa region. Individual bands were excised, in-gel trypsinized and subjected to LC/ESI-MS/MS. The data obtained were searched against human, oral microbial and protease databases. A total of 13 proteases were identified all of which were of mammalian origin. Proteases detected in multiple fractions with cleavage specificities toward arginine and lysine residues, were lactotransferrin, kallikrein-1, and human airway trypsin-like protease. Unexpectedly, ten protease inhibitors were co-identified suggesting they were associated with the proteases in the same fractions. The inhibitors found most frequently were alpha-2-macroglobulin-like protein 1, alpha-1-antitrypsin, and leukocyte elastase inhibitor. Regulation of oral fluid proteolysis is highly important given that an inbalance in such activities has been correlated to a variety of pathological conditions including oral cancer.

Identification of novel proteins secreted byLactobacillus rhamnosusGG grown in de Mann-Rogosa-Sharpe broth

To identify novel proteins secreted by the probiotic bacterium Lactobacillus rhamnosus GG after growth in de Mann-Rogosa-Sharpe broth (MRS), a complex medium often used for the culture of Lactobacillus. The proteins secreted by L. rhamnosus GG strain were precipitated using a trichloroacetic acid-based protocol, resolved by SDS-PAGE, and identified by tandem mass spectrometry (MS/MS). Among the proteins secreted by this bacterium, a leukocyte elastase inhibitor, already present in the MRS broth, was identified. Other proteins such as cell wall hydrolase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoglycerate kinase, and an extracellular transcriptional regulator have been also identified. Lactobacillus rhamnosus GG secretes several proteins during its growth in MRS, some of them with assigned functions in the prevention of the molecular mechanisms that lead to damage in the epithelial barrier (cell wall hydrolase) and in adhesion (GAPDH). The rest of the proteins require further genetic analysis in order to establish their precise roles. None of the proteins bound to mucin or fibronectin. Some of these secreted proteins could be involved in the probiotic effects exerted by L. rhamnosus GG strain, their identification being the first step towards in depth functional studies.

2-Amino- and 2-alkylthio-4H-3,1-benzothiazin-4-ones: synthesis, interconversion and enzyme inhibitory activities.

The synthetic access to 2-sec-amino-4H-3,1-benzothiazin-4-ones 2 was explored. Compounds 2 were available from methyl 2-thioureidobenzoates 1, 2-thioureidobenzoic acids 3, and novel 2-thioureidobenzamides 6, respectively, under different conditions. 2-Alkylthio-4H-3,1-benzothiazin-4-ones 5 have been prepared from anthranilic acid following a two step route. Both, benzothiazinones 2 and 5 underwent ring cleavage reactions to produce thioureas 1 and 6, respectively. Twelve benzothiazinones were evaluated as inhibitors against a panel of eight proteases and esterases to identify one selective inhibitor of human cathepsin L, 2b, and one selective inhibitor of human leukocyte elastase, 5i.

Ｐｈｏｔｏａｇｉｎｇと弾性線維

Long-standing UV exposure causes accumulation of degenerated elastic fibers in the dermis. This phenomenon is termed as solar elastosis and considered to be a histological marker of photoaging. The molecular mechanism by which the degenerated elastic fibers accumulate in the dermis by long-standing UV irradiation remains unknown, but three possible theories have been proposed; suppression of elastic fiber degradation (1)by leukocyte elastase inhibitor (elafin), (2)by advanced glycation end product (AGE) modification of elastin molecule, (3)by racemization of aspartic acid residue of elastin molecule. Leukocyte-derived elastase inhibitor (elafin) was found to (1)colocalize with elastic fiber accumulations in the dermis, (2)bind to elastin molecule via transglutaminase in vitro, (3)be induced by UVA irradiation, and (4)protect elastin molecule from elastolytic degradation. Abnormal accumulation of elastic fibers in solar elastosis therefore may be a secondary response preventing the elastic fibers from leukocyte elastase attack.

Modifications by Olmesartan medoxomil treatment of the platelet protein profile of moderate hypertensive patients

Olmesartan medoxomil is a new angiotensin II receptor blockers (ARB) which exhibits pleiotropic effects that are not fully understood. Our aims were: i) to determine the effect of Olmesartan medoxomil on blood pressure, lipid profile and renal functionality in moderately hypertensive patients with non-controlled blood pressure, ii) to determine if Olmesartan medoxomil may exert anti-inflammatory effects and modify the expression profile of platelet proteins. Thirteen moderate hypertensive patients with non-controlled systolic blood pressure (SBP) and renal function classified as Kidney Disease Outcome Quality Initiative stage 2-3 were included. Patients were treated with Olmesartan medoxomil (20 mg/day) for 6 months. SBP, proteinuria and the plasma levels of cholesterol and low density lipoprotein (LDL)-cholesterol were reduced after the treatment. Olmesartan medoxomil did not modify the circulating plasma levels of a number of proteins associated with inflammation, but reduced the expression level of different platelet proteins including tropomyosin-β chain isotypes 3 and 4, serotransferrin isotypes 1 to 5, the leukocyte elastase inhibitor and the chloride intracellular channel-protein isotype 1. The expression of the gelsolin precursor isotype 4 was increased in the platelets after the treatment. In summary, Olmesartan medoxomil reduced SBP, total and LDL-cholesterol plasma levels and urinary protein excretion and induced changes in the expression of platelet proteins which may be related to some action of the drug at the megakaryocyte level.

Cytotoxic and peptidase inhibitory activities of selected non-hepatotoxic cyclic peptides from cyanobacteria

Toxic cyanobacterial blooms are a rich source of metabolites having a variety of biological activities. Two main groups of cyclic peptides, depsipeptides and ureido linkage-containing peptides, reportedly inhibit serine peptidases. We characterised their inhibitory properties against selected peptidases and investigated their influence on cell viability. The depsipeptide planktopeptin BL1125 is a strong linear competitive tight-binding inhibitor of leukocyte (K(i)=2.9 nm) and pancreatic (K(i)=7.2 nm) elastase and also of chymotrypsin (K(i)=6.1 nm). Anabaenopeptins B and F show no inhibition against chymotrypsin, but inhibit both elastases. The tested cyclic peptides do not inhibit trypsin, urokinase, kallikrein 1 or cysteine peptidases. All three tested cyanopeptides show no short-term cytotoxicity in concentrations of up to 10 mum, but impair the metabolic activity of normal human astrocytes after prolonged exposure (48-96 h), whereas glioblastoma cells, tumour cells of the same type, are resistant. Strong inhibition and relative selectivity of the tested cyanopeptides suggests that they are potential candidates for application in inflammatory diseases and possibly some types of cancers.

Molecular mechanism of L-DNase II activation and function as a molecular switch in apoptosis

The discovery of caspase activation counts as one of the most important finds in the biochemistry of apoptosis. However, targeted disruption of caspases does not impair every type of apoptosis. Other proteases can replace caspases and several so called “caspase independent” pathways are now described. Here we review our current knowledge on one of these pathways, the LEI/L-DNase II. It is a serine protease-dependent pathway and its key event is the transformation of LEI (leukocyte elastase inhibitor, a serine protease inhibitor) into L-DNase II (an endonuclease). The molecular events leading to this change of enzymatic function as well as the cross-talk and interactions of this molecule with other apoptotic pathway, including caspases, are discussed.

Leukocyte Elastase Inhibitor, the precursor of L-DNase II, inhibits apoptosis by interfering with caspase-8 activation

LEI (Leukocyte Elastase Inhibitor), the precursor of the pro-apoptotic molecule L-DNase II, belongs to the ovalbumin subgroup of serpins. Several serpins can inhibit apoptosis: the viral serpin Crm A inhibits Fas or TNFα-induced apoptosis, and overexpression of PAI-2 or PI-9 protects cells from TNFα or granzyme B induced apoptosis. We have previously shown that LEI overexpression protects cells from etoposide-induced apoptosis. The molecular reason of this anti-apoptotic activity is now investigated. We show that, in BHK-21 and HeLa cells, LEI anti-protease activity is essential for its anti-apoptotic effect. The protease inhibited is cathepsin D, released from the lysosome during etoposide treatment. Cathepsin D enhances caspase activity in the cell by cleaving procaspase-8 and LEI overexpression slows down this cleavage, protecting cells from apoptosis. This let us presume that high expression of LEI in tumor cells may reduce the efficiency of etoposide as a chemotherapeutic agent.

Sanguinarine sensitizes tumor necrosis factor-related apoptosis- inducing ligand (TRAIL)-resistant gastric cancer cells though downregulation of Akt and activation caspase-3

The discovery of caspase activation counts as one of the most important finds in the biochemistry of apoptosis. However, targeted disruption of caspases does not impair every type of apoptosis. Other proteases can replace caspases and several so called “caspase independent” pathways are now described. Here we review our current knowledge on one of these pathways, the LEI/L-DNase II. It is a serine protease-dependent pathway and its key event is the transformation of LEI (leukocyte elastase inhibitor, a serine protease inhibitor) into L-DNase II (an endonuclease). The molecular events leading to this change of enzymatic function as well as the cross-talk and interactions of this molecule with other apoptotic pathway, including caspases, are discussed.