Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Leukocytes synthesize a variety of inflammatory mediators that are packaged and stored in the cytoplasm within membrane-bound granules. Upon stimulation, the cells secrete the granule contents via an exocytotic process whereby the granules translocate to the cell periphery, the granule membranes fuse with the plasma membrane, and the granule contents are released extracellularly. We have reported previously that another exocytotic process, release of mucin by secretory cells of the airway epithelium, is regulated by the myristoylated alanine-rich C kinase substrate (MARCKS) (Li Y, Martin LD, Spizz G, Adler KB. MARCKS protein is a key molecule regulating mucin secretion by human airway epithelial cells in vitro. J Biol Chem 2001;276:40982-40990; Singer M, Martin LD, Vargaftig BB, Park J, Gruber AD, Li Y, Adler KB. A MARCKS-related peptide blocks mucus hypersecretion in a mouse model of asthma. Nat Med 2004;10:193-196). In those studies, mucin secretion in vitro and in vivo was attenuated by a synthetic peptide identical to the N-terminus of MARCKS, named the MANS peptide (Li and colleagues, 2001). In this study, we used the MANS peptide to investigate possible involvement of MARCKS in secretion of leukocyte granule proteins. In neutrophils isolated from human blood, phorbol 12-myristate 13-acetate-induced myeloperoxidase release was attenuated in a concentration-dependent manner by MANS but not by equal concentrations of a missense control peptide. In additional studies using human leukocyte cell lines, secretion of eosinophil peroxidase from the eosinophil-like cell line HL-60 clone 15, lysozyme from the monocytic leukemia cell line U937, and granzyme from the lymphocyte natural killer cell line NK-92 were attenuated by preincubation of the cells with MANS but not with the missense control peptide. The results indicate that MARCKS protein may play an important role in the secretion of membrane-bound granules from different leukocytes. MARCKS may be an important component of secretory pathways associated with release of granules by different cell types.
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PMID:A peptide against the N-terminus of myristoylated alanine-rich C kinase substrate inhibits degranulation of human leukocytes in vitro. 1654 3

Vasoactive intestinal peptide (VIP) and nitric oxide (NO) are neurotransmitters involved in the regulation of bronchial and pulmonary vascular tone. Published studies of the effects of VIP on airway mucus secretion have yielded conflicting results. The purpose of this study was to determine the effect of VIP on mucus secretion in the ferret trachea and if this effect was influenced by NO. We used a sandwich enzyme-linked lectin assay to measure mucin secretion and a turbidimetric assay to measure lysozyme (serous cell) secretion from ferret tracheal segments. VIP (10(-7) M) increased mucin secretion over 2 h. VIP (10(-9) to 10(-5) M) stimulated mucin secretion in a dose-dependent fashion. VIP-induced mucin secretion was partially blocked by a VIP receptor antagonist (a chimeric VIP-pituitary adenylate cyclase-activating peptide analog, VIP receptor antagonist) at a 10-fold excess concentration. At all concentrations tested, neither NG-nitro-L-arginine methyl ester, an inhibitor of NO synthase, nor S-nitroso-N-acetyl-penicillamine, an NO donor, had any significant effect on constitutive or VIP-induced mucus secretion. We conclude that VIP-stimulated mucin and lysozyme secretion was both time dependent and dose dependent and that NO neither stimulates nor inhibits mucus secretion in the ferret trachea.
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PMID:Vasoactive intestinal peptide stimulates mucus secretion, but nitric oxide has no effect on mucus secretion in the ferret trachea. 1664 89

The purpose of this study was to investigate the influence of animal mucins on lysozyme activity in solution and on the surface of hydroxyapatite (HA) beads. The effects of animal mucins on lysozyme activity in solution were examined by incubating porcine gastric mucin (PGM) or bovine submaxillary mucin (BSM) with hen egg-white lysozyme (HEWL) or salivary samples. HA-immobilised animal mucins or lysozyme were used to determine the influence of animal mucins on lysozyme activity on HA surfaces. Lysozyme activity was determined by turbidity measurement of a Micrococcus lysodeikticus substrate suspension. Protein concentration was determined by ninhydrin assay. PGM inhibited the activity of HEWL and salivary lysozyme in solution. The amount of inhibition was dependent on mucin concentration, incubation time and temperature, and the structural integrity of the mucin. The inhibition of salivary lysozyme activity by PGM was greater in submandibular/sublingual saliva than in parotid saliva. The inhibition of lysozyme activity by PGM was markedly dependent on pH. However, BSM did not inhibit the in-solution lysozyme activities of HEWL and clarified saliva. Both PGM and BSM bound to HA surfaces, and HA-adsorbed animal mucins increased the subsequent adsorption of lysozyme. When HA beads were exposed to a mixture of HEWL and PGM or BSM, lysozyme activity on the HA surfaces was significantly increased. The results suggest that animal mucins affect lysozyme activity, and the effects are different on HA surfaces compared with in solution. Further research is needed to determine the effect of animal mucins on lysozyme activity in vivo.
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PMID:Influences of animal mucins on lysozyme activity in solution and on hydroxyapatite surfaces. 1671 46

The airway provides numerous defense mechanisms to prevent microbial colonization by the large numbers of bacteria and viruses present in ambient air. An important component of this defense is the antimicrobial peptides and proteins present in the airway surface fluid (ASF), the mucin-rich fluid covering the respiratory epithelium. These include larger proteins such as lysozyme and lactoferrin, as well as the cationic defensin and cathelicidin peptides. While some of these peptides, such as human beta-defensin (hBD)-1, are present constitutively, others, including hBD2 and -3 are inducible in response to bacterial recognition by Toll-like receptor-mediated pathways. These peptides can act as microbicides in the ASF, but also exhibit other activities, including potent chemotactic activity for cells of the innate and adaptive immune systems, suggesting they play a complex role in the host defense of the airway. Inhibition of antimicrobial peptide activity or gene expression can result in increased susceptibility to infections. This has been observed with cystic fibrosis (CF), where the CF phenotype leads to reduced antimicrobial capacity of peptides in the airway. Pathogenic virulence factors can inhibit defensin gene expression, as can environmental factors such as air pollution. Such an interference can result in infections by airway-specific pathogens including Bordetella bronchiseptica, Mycobacterium tuberculosis, and influenza virus. Research into the modulation of peptide gene expression in animal models, as well as the optimization of peptide-based therapeutics shows promise for the treatment and prevention of airway infectious diseases.
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PMID:Antimicrobial peptides in the airway. 1690 21

The expectorant activity of naringenin was studied. Mucus secretion was evaluated in mice by measuring the tracheal output of phenol red. Mucociliary movement function was investigated using a migration method of carbon granules in unanesthetized pigeons. And the effect of naringenin on the secretion of mucin and lysozyme was performed in the rat tracheal ring explants. Naringenin could significantly increase the secretion of phenol red from mouse tracheas at the doses of 30-67 mg/kg (i.g.) (P<0.05). Naringenin, at the dose of 90 mg/kg, increased the tracheal mucociliary velocity (TMV) to 144.4% of control (P<0.01). 100 microM naringenin could enhance the basal lysozyme secretion, but had no effect on the basal mucin secretion from the rat tracheal ring explants. Treatment with naringenin at higher concentration (10 micromol/l) could inhibit the 100 ng/ml lipopolysaccharide (LPS)-induced mucin increase. These data suggest, therefore, that naringenin has the expectorant activity.
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PMID:The expectorant activity of naringenin. 1766 77

Otitis media with effusion (OME) is an inflammatory disease of the middle ear cavity that is associated with middle ear effusions (MEEs), which are frequently mucous and serous for pediatric and adult patients exhibiting low and high responsiveness to medical treatment, respectively. To assess the pathological outcomes in mucous and serous MEEs, their protein compositions were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting in comparison with those in the same patients' sera. A mucin, which is immunochemically identical with nasal mucin, was a characteristic consituent of mucous MEEs (n = 25), being present at the concentration of 59.4 mg/ml and comprising about 60% of the total proteins, but it was not detected in serous MEEs (n = 30) or sera. Serum proteins with molecular weights of less than 260 kDa were detected in serous and mucous MEEs, in which albumin was the major protein. Albumin, IgM and alpha1-acid glycoprotein, and lysozyme, IgA and IgG in MEEs were present at lower and higher concentrations than in sera, respectively. The ratios of IgA, IgG, IgM and alpha1-acid glycoprotein to albumin in mucous MEEs were 4-, 3-, 1.4- and 1.0-times higher than those in the respective pediatric sera, and those in serous MEEs were 1.7-, 1.7-, 0.6- and 0.3-times higher than those in adult sera. Also, the concentrations of lysozyme in mucous and serous MEEs were 19 and 3 microg/ml, but those in pediatric and adult sera were negligible. These results indicate that the contents of these proteins, in comparison to albumin, might be useful criteria for assessing the inflammation level in MEEs.
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PMID:Gel chromatographic characterization of proteins in mucous and serous middle ear effusions of patients with otitis media in comparison to serum proteins. 1789 10

Eight Bifidobacterium longum strains, including reported probiotic strains (commercial and noncommercial), collection strains, and laboratory isolates, were investigated for their ability to adhere to mucin as well as their ability to tolerate acid and bile. Strains could be discriminated based on their sensitivity at pH values of 2.0 to 2.5 and bile concentrations of 0.5% to 2.0%. B. longum NCC 2705, a strain known for its probiotic properties, showed the highest resistance to gastrointestinal conditions, whereas the commercial probiotic strains B. longum BB 536 and SP 07/3 were the least resistant. In parallel, the human isolate B. longum BIF 53 showed the highest adhesion to mucin, whereas the commercial probiotic strains B. longum W 11, BB 536, and SP 07/3 were the least adhesive. The bacterial adhesion to mucin of strains B. longum NCC 2705 and BIF 53 could be reduced by lysozyme, indicating that cell-wall components are involved in the adhesion process. These results showed that there is no obvious link between adhesion and resistance to gastrointestinal conditions and the probiotic status of the studied strains. This calls for a definition of conditions for in vitro tests that better predict the in vivo functionality of probiotic strains.
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PMID:Resistance to simulated gastrointestinal conditions and adhesion to mucus as probiotic criteria for Bifidobacterium longum strains. 1833 Jun 33

The pic gene is harbored on the chromosomes of three important pathogens: enteroaggregative Escherichia coli (EAEC), uropathogenic E. coli (UPEC), and Shigella flexneri. Since Pic is secreted into the intestinal lumen during EAEC infection, we sought to identify intestinal-mucosal substrates for Pic. Pic did not damage epithelial cells, cleave fodrin, or degrade host defense proteins embedded in the mucus layer (sIgA, lactoferrin and lysozyme). However, by using a solid-phase assay to evaluate the mucinolytic activity of EAEC Pic, we documented a specific, dose-dependent mucinolytic activity. A serine protease inhibitor and an enzymatically inactive variant of Pic were used to show that the Pic serine protease motif is required for mucinolytic activity. Pic binds mucin, and this binding was blocked in competition assays using monosaccharide constituents of the oligosaccharide side chains of mucin. Moreover, Pic mucinolytic activity decreased when sialic acid was removed from mucin. Thus, Pic is a mucinase with lectin-like activity that can be related to its reported hemagglutinin activity. Our results suggest that EAEC may secrete Pic into the intestinal lumen as a strategy for penetrating the gel-like mucus layer during EAEC colonization.
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PMID:The serine protease motif of Pic mediates a dose-dependent mucolytic activity after binding to sugar constituents of the mucin substrate. 1853 33

The subglottic region of the larynx is of high clinical relevance with regard to infections and malignancies. Little is known about the distribution of mucins and antimicrobial substances in this area. In this study, we have investigated the mucin distribution in the normal subglottis of the larynx. Moreover, we analysed the expression of lysozyme and lactoferrin in this area. Therefore, the subglottic region of 34 larynges was investigated immunohistochemically with different antibodies to mucins and antimicrobial substances. The epithelium reacted positive with antibodies to mucins MUC1 (34/34), 5AC (26/34), 5B (10/34), 7 (8/34), 8 (10/34) and 16 (19/34); submucosal glands were positive to mucins MUC1 (34/34), 5B (10/34), 7 (8/34), and 16 (19/34); high columnar epithelial cells and serous parts of subepithelial seromucous glands were also positive for lysozyme (34/34) and lactoferrin (34/34). The results show that human subglottic epithelium and subepithelial submucosal glands produce a broad spectrum of mucins that is almost comparable with that in other areas of the respiratory tract. We hypothesize that the mucin diversity of the subglottis has an impact on positive functional consequences during vocal production and antimicrobial defence. This antimicrobial defence is supported by synthesis and secretion of antimicrobial substances such as lysozyme and lactoferrin. Moreover, knowledge of the observed distribution pattern of mucins in the subglottis can be a useful tool for a classification of subglottic laryngeal carcinomas.
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PMID:Distribution of mucins and antimicrobial substances lysozyme and lactoferrin in the laryngeal subglottic region. 1865 60

Hemorrhagic fever with renal syndrome (HFRS) and Hantavirus pulmonary syndrome are zoonotic diseases caused by rodent borne hantaviruses. Transmission to humans occurs usually by inhalation of aerozolized virus-contaminated rodent excreta. Although human-to-human transmission of Andes hantavirus has been observed, the mode of transmission is currently not known. Saliva from Puumala hantavirus (PUUV)-infected patients was shown recently to contain viral RNA. To test if human saliva interferes with hantavirus replication, the effect of saliva and salivary proteins on hantavirus replication was studied. It was observed that saliva from healthy individuals reduced Hantaan hantavirus (HTNV) infectivity, although not completely. Furthermore, HTNV was resistant against the antiviral capacity of histatin 5, lysozyme, lactoferrin, and SLPI, but was inhibited by mucin. Inoculation of bank voles (Myodes glareolus) with HFRS-patient saliva, positive for PUUV-RNA, did not induce sero-conversion. In conclusion, no evidence of infectious virus in patient saliva was found. However, the in vitro experiments showed that HTNV, the prototype hantavirus, is insensitive to several antiviral salivary proteins, and is partly resistant to the antiviral effect of saliva. It therefore remains to be shown if human saliva might contain infectious virions early during infection, that is, before seroconversion.
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PMID:Antiviral effect of human saliva against hantavirus. 1904 Feb 88


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