Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.4.3 (phospholipase C)
 18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Enzyme-linked immunosorbent assay (ELISA) was used for IgG antibody determination to teichoic acid and alpha-toxin from Staphylococcus aureus in 65 patients with cystic fibrosis (CF). In patients chronically colonized with S. aureus, elevated titres to teichoic acid were found in 13/35 (37%) patients, to alpha-toxin in 12/35 (34%) and to either antigen in 18/35 (51%). Patients with elevated titres to teichoic acid had a significantly lower X-ray score than patients with normal titres. The highest titres against both teichoic acid and alpha-toxin were seen in patients not receiving optimal treatment. These findings suggest that staphylococci contribute to the tissue damage in CF and that the determination of antibodies especially to staphylococcal teichoic acid might be of value in the diagnosis and management of staphylococcal infections in patients with CF.
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PMID:Antibodies to staphylococcal teichoic acid and alpha toxin in patients with cystic fibrosis. 395 69

Enzyme-linked immunosorbent assay (ELISA) was used to measure the antibody response to Pseudomonas aeruginosa exotoxin A, elastase, alkaline protease and phospholipase C in patients with cystic fibrosis (CF). Only the chronically colonized patients showed elevated antibody titres to phospholipase C (22/22 patients), alkaline protease (16/22 patients), exotoxin A (15/22 patients) and elastase (5/22 patients). In a few patients where serial specimens were available, rising titres were recorded to all four antigens during periods of active infection. Antibiotic treatment resulted in decrease of titres against all four antigens, but only the anti-exotoxin A and anti-elastase titres decreased to normal levels. Titres to phospholipase C were the least influenced by antibiotic treatment. The results imply different roles for these exoproteins in chronic colonization versus active infection. The levels of P. aeruginosa antibodies to exoproteins could probably be used in monitoring treatment of patients with CF.
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PMID:Relation between antibody response to Pseudomonas aeruginosa exoproteins and colonization/infection in patients with cystic fibrosis. 644 48

The virulence of Pseudomonas aeruginosa, which is easily differentiated from the two other most common pseudomonad pathogens, is low. This species primarily causes disease in patients with local anatomic changes or in the immune compromized hosts. A number of bacterial factors are involved in the pathogenesis of the microbe. Surface structures like the glycocalyx-capsular material-is involved in attachment to mucosal surfaces and resistance against phagocytosis and immunolysis of cells. The interference with bacterial components on mucociliar clearance of the bronchial tract have been described. In cystic fibrosis local environmental substances enhancing the production of capsular material have been described and the tendency for colonization of mucoid strains in cystic fibrosis probably is related to these factors. Another general component of gram-negative bacteria is endotoxin, but the toxicity of this cell wall constituent is relatively low in P. aeruginosa. A number of proteolytic enzymes with a probable role in disease have been described: collagenase, fibrinolysin, elastase, caseinase, and gelatinase. A proteolytic enzyme with activity against substances like casein, egg albumin, gluten, and haemoglobin has been described. A component like exotoxin A can produce skin lesions and antibodies produced with toxoid of exotoxin A are protective against this bacterial agent. Enterotoxin has been described based on rabbit intestinal loop preparations, but has not been further characterized and diarrhoea is rarely caused by P. aeruginosa. Haemolytic effect has been caused by a heat labile phospholipase C and by a heat stabile moiety. A leucocidin has been described: this may in part be capsular material. In addition, an exoenzyme S has been suggested as a virulence factor.
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PMID:Pathogenetic factors of Pseudomonas aeruginosa. 679 59

alpha 1-Adrenergic (alpha 1-AR) agents stimulate NaCl(K) cotransport and phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P2]-specific phospholipase C in human trachea and nasal polyp epithelial cells. One second messenger generated by PtdIns(4,5)P2 degradation is inositol trisphosphate. We now show that diglycerides (DG) are also generated during alpha 1-AR stimulation. In cells prelabeled with [3H]arachidonic acid, alpha 1-AR agents produced a biphasic DG generation in normal and cystic fibrosis (CF) cells that is blocked by pertussis toxin. The early DG peak closely paralleled PtdIns(4,5)P2 degradation, stimulation of cotransport by phorbol 12-myristate 13-acetate (PMA), and inhibition of cotransport by the protein kinase C (PKC) inhibitor staurosporine. This suggests that cotransporter activation requires PKC-protein phosphorylation. This possibility was tested using the protein phosphatase inhibitor okadaic acid. Okadaic acid elevated bumetanide-sensitive Cl efflux. Staurosporine also blocked > 63% of okadaic-acid-stimulated Cl transport. The late DG peak did not support hormone-stimulated cotransport. The results demonstrate that DGs are a pivotal link between alpha 1-AR stimulation and NaCl(K) cotransport activation with a role for PKC and protein phosphorylation. alpha 1-AR intracellular signaling mechanisms apparently operate normally in CF cells.
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PMID:The role of protein kinase C in alpha-adrenergic regulation of NaCl(K) cotransport in human airway epithelial cells. 790 Aug 23

The role of platelets in acute and chronic infection has been widely discussed in various disease processes. We studied the effects of two lipolytic enzymes (phospholipase C, lipase) secreted by Pseudomonas aeruginosa strains isolated from cystic fibrosis (CF) patients with regard to 12-hydroxyeicosatetraenoic acid (12-HETE) generation from human platelets. Both phospholipase C (PLC) and lipase were secreted into the culture supernatant at the end of the logarithmic growth phase. Indeed, only culture supernatants obtained from the late logarithmic/early stationary phase of CF strains induced the generation of 12-hydroxyeicosatetraenoic acid (12-HETE) (from 15 +/- 9 to 370 +/- 98 ng, n = 7). Purified P. aeruginosa lipase itself generated only small amounts of 12-HETE from human platelets with a maximum of 30 +/- 7 ng/10(8) platelets at the highest concentration tested (20 nkat). A partially purified culture supernatant from P. aeruginosa strain PAO1 containing phospholipase C and lipase, but lacking glycolipid and protease activities, induced time- and dose-dependently a significant 12-HETE generation from human platelets. Maximal 12-HETE generation was observed at the highest enzyme concentrations tested (PLC: 1.35 nkat, lipase: 3.7 nkat/10(8) platelets). To analyze whether lipase exhibits a modulatory role on PLC-induced 12-HETE generation from human platelets we inhibited lipase activity in the P. aeruginosa partially purified culture supernatant by treatment with the lipase-specific inhibitor hexadecylsulfonylfluoride (AMSF) leaving the activity of PLC unaffected (lipase-free culture supernatant). The capacity of lipase-free culture supernatant to induce 12-HETE generation was diminished by up to 100% depending on the PLC activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Induction of inflammatory mediator release (12-hydroxyeicosatetraenoic acid) from human platelets by Pseudomonas aeruginosa. 795 Apr 3

Anti-Pseudomonas aeruginosa antibodies were studied by Western Blot, ELISA-exotoxin A and ELISA-phospholipase C for 91 serums from 31 patients with cystic fibrosis. More, for the two enzyme-linked immunosorbent assays, 44 serums from 44 healthy individuals were studied as controls. The study of these three parameters revealed the followings: with no infection by Pseudomonas aeruginosa all the results were negative, at the beginning of the infection, anti-exotoxin A antibodies appeared in first, followed in some cases by the reactions of Western Blot, anti-phospholipase C antibodies became positive at last and went on a par with the installation of the chronic characteristic of the infection, as soon as the chronicity were indisputable, the three methods revealed elevated serum antibodies amounts. Generally there was a correlation between detected antibodies and Pseudomonas aeruginosa isolation in sputum. Among these three methods, ELISA-exotoxin A appeared to be the most interesting because of its good reproducibility and its early positivity, before the others methods and sometimes before Pseudomonas aeruginosa isolation. It would be a significant argument to establish as soon as possible an antimicrobial therapy.
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PMID:[Serodiagnosis of Pseudomonas aeruginosa infections in mucoviscidosis: comparative study of Western blotting, ELISA exotoxin A and ELISA phospholipase C]. 812 17

The mechanism by which inositol 3,4,5,6-tetrakisphosphate (Ins(3,4,5, 6)P4) regulates chloride (Cl-) secretion was evaluated in the colonic epithelial cell line T84 using whole cell voltage clamp techniques. Our studies focused on the calcium-dependent chloride conductance (gClCa) that was activated either by mobilizing intracellular calcium (Cai) stores with thapsigargin or by introduction of the autonomous, autophosphorylated calmodulin-dependent protein kinase II (CaMKII) into the cell via the patch pipette. Basal concentrations of Ins(3,4,5,6)P4 (1 microM) present in the pipette solution had no significant effect on Cl- current; however, as the concentration of the polyphosphate was increased there was a corresponding reduction in anion current, with near complete inhibition at 8-10 microM Ins(3,4,5,6)P4. Corresponding levels are found in cells after sustained receptor-dependent activation of phospholipase C. The Ins(3,4,5, 6)P4-induced inhibition of gClCa was isomer specific; neither Ins(1, 3,4,5)P4, Ins(1,3,4,6)P4, Ins(1,4,5,6)P4, nor Ins(1,3,4,5,6)P5 induced current inhibition at concentrations of up to 100 microM. Annexin IV also plays an inhibitory role in modulating gClCa in T84 cells. When 2 microM annexin IV was present in the pipette solution, a concentration that by itself has no effect on gClCa, the potency of Ins(3,4,5,6)P4 was approximately doubled. The combination of Ins(3,4,5,6)P4 and annexin IV did not alter the in vitro activity of CaMKII. These data demonstrate that Ins(3,4,5,6)P4 is an additional cellular signal that participates in the control of salt and fluid secretion, pH balance, osmoregulation, and other physiological activities that depend upon gClCa activation. Ins(3,4,5,6)P4 metabolism and action should also be taken into account when designing treatment strategies for cystic fibrosis.
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PMID:Inositol 3,4,5,6-tetrakisphosphate inhibits the calmodulin-dependent protein kinase II-activated chloride conductance in T84 colonic epithelial cells. 866 2

The cystic fibrosis transmembrane regulator (CFTR) is a Cl- channel regulated by adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase A. A cAMP-independent activation has been recently shown for the protein tyrosine kinase inhibitor genistein in CFTR-transfected NIH/3T3 fibroblasts. We further studied the role of genistein on Cl- secretion in HT-29/B6 and T84 colonic epithelial cells, which express native CFTR in their apical membranes. Transepithelial Cl- secretion was more effectively stimulated in T84 cells when compared with HT-29/B6 cells by mucosal perfusion with 50 microM genistein. Genistein, like the cAMP agonist forskolin, stimulated CFTR activity in cell-attached patches of single cells with similar slope conductances of 8.5 +/- 0.5 and 9.2 +/- 0.3 pS, respectively. Monolayers in Ussing chambers were basolaterally permeabilized with the pore former alpha-toxin, and gradient-driven Cl- current across the apical membrane (ICl) was measured. ICl was stimulated by serosal (i.e., cytosolic) cAMP (half-maximal stimulatory concentration = 9.8 +/- 1.9 microM). In the presence of cAMP (> 5 microM), subsequent mucosal, but not serosal, addition of genistein further increased Icl by approximately 16%; in the absence of cytosolic cAMP, genistein had no effect on ICl. The inactive analogue daidzein had no effect. When cAMP agonists were removed in the continued presence of genistein, ICl remained elevated in both permeabilized and intact monolayers as well as in cell-attached patches of single cells. In addition, genistein blocked K- currents across the basolateral membrane in apically amphotericin B-permeabilized monolayers (half maximal inhibitory concentration = 44.2 +/- 8.1 microM). Therefore, in intact epithelia, the overall secretory response to genistein is composed of stimulatory effects on the apical CFTR and inhibitory effects on the basolateral K+ conductance. We propose that genistein blocks a phosphatase, which regulates CFTR during cAMP-dependent stimulation.
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PMID:Alternate stimulation of apical CFTR by genistein in epithelia. 877 53

1. The defective Cl- secretion characteristic of cystic fibrosis airway epithelial cells can be bypassed by an alternative Ca2+ dependent Cl- secretory pathway that is activated by extracellular nucleotides, e.g. uridine-5'triphosphate (UTP), acting on P2U purinoceptors. Since UTP is susceptible to hydrolysis by nucleotidases and phosphatases present in the airways, the identification of stable P2U-purinoceptor agonists would be of therapeutic relevance. 2. Uridine-5'-O-(3-thiotriphosphate) (UTP gamma S) was synthesized by nucleoside diphosphate kinase-catalyzed transfer of the gamma-phosphorothioate from guanosine-5'-O-(3-thiotriphosphate) (GTP gamma S) or adenosine-5' = O-(3-thiotriphosphate) (ATP gamma S) to UDP. Formation of UTP gamma S was illustrated by observation of transfer of 35S from [35S]-GTP gamma S and transfer of 3H from [3H]-UDP. The chemical identity of high performance liquid chromatography (h.p.l.c.)-purified UTP gamma S was confirmed by nuclear magnetic resonance analysis. 3. Human 1321N1 astrocytoma cells stably expressing the phospholipase C-coupled human P2U-purinoceptor were utilized to test the activity of UTP gamma S. UTP gamma S (EC50 = 240 nM) was essentially equipotent to UTP and ATP for stimulation of inositol phosphate formation. 4. Unlike [3H]-UTP, [3H]-UTP gamma S was not hydrolyzed by alkaline phosphatase, acid phosphatase, or apyrase. Moreover, no hydrolysis was detected during a 1 h incubation with human nasal epithelial cells. 5. UTP gamma S was equally potent and efficacious with UTP for stimulation of Cl- secretion by human nasal epithelium from both normal donors and cystic fibrosis patients. Based on its high potency and resistance to hydrolysis, UTP gamma S represents a promising compound for treatment of cystic fibrosis.
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PMID:Enzymatic synthesis of UTP gamma S, a potent hydrolysis resistant agonist of P2U-purinoceptors. 882 64

The mechanism(s) of chronic airway inflammation in cystic fibrosis (CF) remains poorly understood. We studied Ca2+-induced release of arachidonic acid (AA), a precursor of proinflammatory lipid mediators, in epithelial cell lines with the deltaF508 mutation in CF transmembrane conductance regulator (CFTR) gene and in those lacking this mutation or cells in which this mutation was corrected by a functional CFTR gene transfer. We found that: (i) the mutant cells manifested an abnormally high Ca2+-induced AA release as compared to controls, (ii) AA release appeared to be catalyzed by a phospholipase A2 (PLA2) but not by phospholipase C followed by diacylglycerol lipase, and (iii) either correction of the CFTR-mutation or inhibition of PLA2 activity rectified this AA release abnormality. Taken together, our results suggest that CFTR mutation is associated with an intrinsic abnormality in AA release by epithelial cells carrying the deltaF508 mutation and suggest that the mechanism of chronic airway inflammation in CF, at least in part, involves this abnormality. These results also partly explain the effectiveness of high-dose ibuprofen therapy in arresting the progression of destructive lung disease in CF. Furthermore, they raise the possibility that correction of abnormal AA release by inhibiting PLA2 activity may improve the therapeutic benefits of ibuprofen.
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PMID:Cystic fibrosis gene mutation (deltaF508) is associated with an intrinsic abnormality in Ca2+-induced arachidonic acid release by epithelial cells. 921 68


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