Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The disruption of the molecular organization of the plasma membrane of leukocytes by phagocytosable particles, or by agents such as surfactants, antibodies, phospholipase C, fatty acids and chemotactic factors, leads to a stimulation of the phagocyte oxidative metabolism. Concanavalin A (Con A) has been used as a tool to study the mechanism of this metabolic regulation. The binding of Con A to the surface of polymorphonuclear leukocytes (PMNL) or macrophages produces a rapid enhancement of oxygen uptake and glucose oxidation through the hexose monophosphate pathway (HMP). This is explained by an activation of the granular NADPH oxidase, the key enzyme in the metabolic stimulation. The effect of Con A is not due to endocytosed lectin, since Con A covalently coupled to large sepharose beads still acts as stimulant. The metabolic changes caused by Con A are reversible. If, after the onset of stimulation, sugars with high affinity for Con A are added to the leukocyte suspension, the activity of granular NADPH oxidase and the rate of respiration and glucose oxidation return to their resting values. The metabolic burst, while partially supressed by treatment of PMNL with iodoacetate, sodium flouride and cytochalasin B, is slightly increased by colchicine. Con A induces a selective release of granular enzymes (beta-glucuronidase, peroxidase, alkaline phosphatase) from PMNL, whereas no leakage of cytoplasmic enzymes is observed. The enzyme release is inhibited by iodoacetate and by drugs known to increase cell levels of cyclic AMP. Based on a current view of the mode of interaction between Con A and cell surfaces, a model of the metabolic disruption of leukocytes is presented.
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PMID:Concanavalin A as a probe for studying the mechanism of metabolic stimulation of leukocytes. 16 45

Neutrophils from cystic fibrosis (CF) patients have been shown previously to be defective in their response (beta-glucuronidase exocytosis, NADPH oxidase activation) to the chemotactic peptide FMLP. In this work, we attempted to identify the defective step in this response. We showed that stimulated CF and control neutrophils do not differ in the formation of inositol phosphates. On the other hand, direct stimulation of protein kinase C with phorbol myristate acetate (PMA) revealed a subnormal stimulation of beta-glucuronidase exocytosis in CF neutrophils. Furthermore, retroinhibition exerted by PMA-activated protein kinase C on stimulated inositol phosphates or on beta-glucuronidase exocytosis was marginal or absent in CF neutrophils, whereas it was significant in the case of control neutrophils. Our observations suggest that the CFTR gene is expressed in neutrophils and is involved in protein kinase C-mediated actions.
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PMID:Defective protein kinase C-mediated actions in cystic fibrosis neutrophils. 189 35

Whereas the chemotactic peptide, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMet-Leu-Phe), induced NADPH-oxidase-catalyzed superoxide (O2-) formation in human neutrophils, purine and pyrimidine nucleotides per se did not stimulate NADPH oxidase but enhanced O2- formation induced by submaximally and maximally stimulatory concentrations of fMet-Leu-Phe up to fivefold. On the other hand, FMet-Leu-Phe primed neutrophils to generate O2- upon exposure to nucleotides. At a concentration of 100 microM, purine nucleotides enhanced O2- formation in the effectiveness order adenosine 5'-O-[3-thio]triphosphate (ATP[gamma S]) greater than ITP greater than guanosine 5'-O-[3-thio]triphosphate (GTP[gamma S]) greater than ATP = adenosine 5'-O-[2-thio]triphosphate (Sp-diastereomer) = GTP = guanosine 5'-O-[2-thio]diphosphate (GDP[beta S] = ADP greater than adenosine 5'-[beta, gamma-imido]triphosphate = adenosine 5'-O-[2-thio]triphosphate] (Rp-diastereomer). Pyrimidine nucleotides stimulated fMet-Leu-Phe-induced O2- formation in the effectiveness order uridine 5'-O-[3-thio]triphosphate (UTP[gamma S]) = UTP greater than CTP. Uracil (UDP[beta S]) = uridine 5'-O[2-thio]triphosphate (Rp-diastereomer) (Rp)-UTP[beta S]) = UTP greater than CTP. Uracil nucleotides were similarly effective potentiators of O2- formation as the corresponding adenine nucleotides. GDP[beta S] and UDP[beta S] synergistically enhanced the stimulatory effects of ATP[gamma S], GTP[gamma S] and UTP[gamma S]. Purine and pyrimidine nucleotides did not induce degranulation in neutrophils but potentiated fMet-Leu-Phe-induced release of beta-glucuronidase with similar nucleotide specificities as for O2- formation. In contrast, nucleotides per se induced aggregation of neutrophils. Treatment with pertussis toxin prevented aggregation induced by both nucleotides and fMet-Leu-Phe. Our results suggest that purine and pyrimidine nucleotides act via nucleotide receptors, the nucleotide specificity of which is different from nucleotide receptors in other cell types. Neutrophil nucleotide receptors are coupled to guanine-nucleotide-binding proteins. As nucleotides are released from cells under physiological and pathological conditions, they may play roles as intercellular signal molecules in neutrophil activation.
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PMID:Purine and pyrimidine nucleotides potentiate activation of NADPH oxidase and degranulation by chemotactic peptides and induce aggregation of human neutrophils via G proteins. 254 Sep 69

The protein kinase C inhibitor staurosporine influenced in different ways the functions of human neutrophils. Staurosporine prevented the enhanced protein phosphorylation in phorbol ester- and N-formylmethyionyl-leucylphenylalanine (fMLP)-stimulated cells, and was a powerful inhibitor of the respiratory burst induced by phorbol myristate acetate [IC50 (concentration causing 50% inhibition) 17 nM] and the chemotactic peptides fMLP and C5a (IC50 24 nM). It did not alter, however, the superoxide production by cell-free preparations of NADPH oxidase. Staurosporine had no effect on agonist-dependent changes in cytosolic free Ca2+ and exocytosis of specific and azurophil granules, and showed only a slight inhibition of the release of vitamin B12-binding protein induced by phorbol myristate acetate (decreased by 40% at 200 nM). On the other hand, staurosporine also exhibited neutrophil-activating properties: it induced the release of gelatinase (from secretory vesicles) and vitamin-B12-binding protein (from specific granules). These effects were protracted, concentration-dependent, insensitive to Ca2+ depletion, and strongly enhanced by cytochalasin B. Staurosporine, however, did not induce the release of beta-glucuronidase or elastase (from azurophil granules). Except for the sensitivity to cytochalasin B, these properties suggest a similarity between the exocytosis-inducing actions of staurosporine and PMA. The results obtained with staurosporine provide further evidence that different signal-transduction processes are involved in neutrophil activation, and suggest that protein phosphorylation is required for the induction of the respiratory burst, but not for exocytosis.
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PMID:Staurosporine inhibits the respiratory burst and induces exocytosis in human neutrophils. 255 21

Using serum-coated zymosan, the generation of reactive oxidants by measurement of chemiluminescence was shown to be significantly enhanced in isolated peripheral psoriatic neutrophils compared to normal controls. This response was observed irrespective of whether zymosan was opsonized with fresh autologous or normal AB serum. However, this increased activity was reduced with zymosan was opsonized with serum that was preheated at 56 degrees C for 30 min. There was no statistical correlation of chemiluminescence activity with degranulation of beta-glucuronidase in either normal or psoriatic subjects. In addition, chemiluminescence produced by normal cells was significantly increased when zymosan was opsonized with psoriatic serum. The plasma membrane-bound enzyme, NAD(P)H oxidase, which produces superoxide in response to phagocytic stimulation, was significantly increased in psoriatic neutrophils compared to normal controls. These data add further evidence for activated neutrophils in psoriasis.
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PMID:Enhanced chemiluminescence production by phagocytosing neutrophils in psoriasis. 339 84

In order to resolve discrepancies in the literature concerning the subcellular localization of NADPH oxidase, we disrupted human neutrophils by nitrogen cavitation and fractionated the subcellular organelles on a discontinuous sucrose density gradient. The lightest fraction was 20- to 40-fold enriched for plasma membranes as determined by the marker enzymes alkaline phosphatase and phosphodiesterase I as well as by the ratio of lipid phosphorus to protein. There was a significant decrease in the specific activities of the granule markers myeloperoxidase, lysozyme, and beta-glucuronidase. An intermediate fraction was enriched in membrane markers but not to the extent the lightest fraction was enriched. This fraction contained more granular contamination, as shown by the marker enzymes. In contrast, the densest bands of the gradient were enriched for granule markers with little contamination by plasma membrane. Superoxide generation and NADP formation were primarily associated with the two membrane-enriched fractions from polymorphonuclear leukocytes stimulated with phorbol myristate acetate. The NADP formation associated with a dense granule fraction observed previously in our laboratory was probably due to a cyanide-stimulated oxidation of NADPH by myeloperoxidase.
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PMID:Co-localization of superoxide generation and NADP formation in plasma membrane fractions from human neutrophils. 609 76

All of the common cytochalasins activate superoxide anion release and exocytosis of beta-N-acetylglucosaminidase and lysozyme from guinea-pig polymorphonuclear leukocytes (neutrophils) incubated in a buffered sucrose medium. Half-maximal activation of both processes is produced by approx. 0.2 microM cytochalasin A, C greater than 2 microM cytochalasin B greater than or equal to 4-5 microM cytochalasin D, E. While maximal rates of O2- release and extents of exocytosis require extracellular calcium (1-2 mM), replacing sucrose with monovalent cation chlorides is inhibitory to neutrophil activation by cytochalasins. Na+, K+ or choline inhibit either cytochalasin B- or E-stimulated O2- production with IC50 values of 5-10 mM and inhibition occurs whether Cl-, NO3- or SCN- is the anion added with Na+ or K+. Release of beta-N-acetylglucosaminidase in control or cytochalasin B-stimulated cells is inhibited by NaCl(IC50 approximately 10 mM), while cytochalasin E-stimulated exocytosis is reduced less and K+ or choline chloride are ineffective in inhibiting either cytochalasin B- or E-stimulated exocytosis. Release of beta-glucuronidase, myeloperoxidase or acid phosphatase from neutrophils incubated in buffered sucrose is not stimulated by cytochalasin B. Stimulation of either O2- or beta-N-acetylglucosaminidase release by low concentrations of cytochalasin A is followed by inhibition of each at higher concentrations. It appears that all cytochalasins can activate both NAD(P)H oxidase and selective degranulation of neutrophils incubated in salt-restricted media and that differential inhibition of these two processes by monovalent cations and/or anions is produced at some step(s) subsequent to cytochalasin interaction with the cell.
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PMID:Activation of superoxide production and differential exocytosis in polymorphonuclear leukocytes by cytochalasins A, B, C, D and E. Effects of various ions. 627 16

The subcellular distribution of the NADPH oxidase of guinea-pig peritoneal-elicited macrophages was investigated. Post-nuclear supernatants obtained from PMA-stimulated macrophages were fractionated in discontinuous sucrose gradients. The NADPH oxidase was found to be enriched at the interface between 20 and 34 per cent sucrose. This interface was also enriched in 5'-nucleotidase, a plasma membrane marker and in glucose-6-phosphatase and NADPH-cytochrome c reductase, two endoplasmic reticulum markers. The distribution in the gradient of beta-glucuronidase, a marker of lysosomes and of succinate dehydrogenase, a marker of mitochondria was clearly different from that of NADPH oxidase and of the markers of plasma membrane and of endoplasmic reticulum. These results indicated that in stimulated-elicited macrophages the NADPH oxidase is associated with a membrane fraction. With the fractionation technique employed it was not possible to clarify whether the oxidase is located in the plasma membrane or in the endoplasmic reticulum. In order to clarify this matter the isolation of phagosomes was performed. NADPH oxidase was found to be enriched in the phagosomal fraction. Phagosomes were also found to be enriched in the plasma membrane marker 5'-nucleotidase. Glucose-6-phosphatase,, a marker of endoplasmic reticulum, and beta-glucuronidase, a marker of lysosomes were not enriched in the phagosomal fraction. The results obtained clearly suggest that the activated NADPH oxidase of peritoneal elicited macrophages of guinea pig is located in the plasma membrane.
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PMID:Plasma membrane and phagosome localisation of the activated NADPH oxidase in elicited peritoneal macrophages of the guinea-pig. 706 27

Peritoneal dialysis effluent from patients with end-stage renal failure contains a low-molecular-weight solute that inhibits the killing of phagocytosed Staphylococcus epidermidis by polymorphonuclear leukocytes (PMN). This observation has been investigated by using luciginen-enhanced chemiluminescence to measure PMN NADPH oxidase activity, CD11b/CD18 expression and lactoferrin release to measure secondary granule discharge, and cellular levels of beta-glucuronidase (EC 3.2.1.31) to measure changes in primary granules. Peritoneal dialysis effluent had no effect on the loss of intracellular beta-glucuronidase from normal unstimulated PMN or from PMN stimulated with S. epidermidis. It did, however, cause a concentration-dependent (0 to 70%; vol/vol) increase in expression of CD11b/CD18 and NADPH oxidase activity. CD11b/CD18 expression increased over 20 min before starting to plateau. Release of lactoferrin by the same cells demonstrated a strong positive correlation with integrin expression (P < 0.001, Spearman's rank correlation coefficient). When dialysis effluent-treated PMN were stimulated with formyl-methionylleucylphenylalanine, integrin expression, release of lactoferrin, and NADPH oxidase activity were greater than in PMN treated with formyl-methionylleucylphenylalanine alone. Under these conditions, a concentration-dependent increase in CD11b/ CD18 and lactoferrin release were observed only at a concentration between 0 and 30% (vol/vol) dialysis effluent, while a concentration-dependent increase in oxidase activity was seen at a concentration between 0 and 70% (vol/vol). The results suggest that dialysis effluent does not affect PMN primary granule release but does cause increased release of secondary granules and an increase in NADPH oxidase activity in both unstimulated and stimulated PMN.
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PMID:Primary and secondary granule release by polymorphonuclear leukocytes exposed to peritoneal dialysis effluent. 749 50

Pyelonephritis is the most common urinary tract infection affecting females of all age groups. Despite concerted efforts the mechanism of renal injury in pyelonephritis is not clearly understood. In the present study we have made an attempt to characterise the mediators of inflammatory insult in an experimental model of ascending pyelonephritis. Mice infected with Escherichia coli O6:K13:H1 were sacrificed at 2, 7 and 14 days post-infection. Luminol-dependent chemiluminescence response, NADPH oxidase, acid phosphatase, beta-glucuronidase and N-acetyl-beta-D-glucosaminidase activities were monitored in circulating as well as renal phagocytic cells in order to determine the role of reactive oxygen species and lysosomal enzymes in genesis of renal injury. We have demonstrated that reactive oxygen species are generated at the initiation of infection and the levels increase progressively during the course of infection. While intracellular release of lysosomal enzymes was seen in all groups, extracellular release was primarily observed at 7 and 14 days post-infection only. The results indicate that while reactive oxygen species play a significant role in tissue injury during all stages of infection, lysosomal enzyme release in extracellular milieu augments tissue destruction at later stages only.
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PMID:Oxygen-dependent and -independent mechanisms of renal injury in experimental ascending pyelonephritis. 882 96


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