scholarly journals Regulation of macrophage lysosomal enzyme secretion: role of arachidonate metabolites, divalent cations and cyclic AMP

1980 ◽  
Vol 44 (1) ◽  
pp. 299-315
Author(s):  
R.M. McMillan ◽  
D.E. Macintyre ◽  
J.E. Beesley ◽  
J.L. Gordon
Keyword(s):  
Cyclic Amp ◽  
Lysosomal Enzyme ◽  
Lysosomal Enzymes ◽  
Divalent Cations ◽  
Cell Types ◽  
Enzyme Secretion ◽  
Ionophore A23187 ◽  
Enzyme Release ◽  
Arachidonate Metabolites

We have investigated the role in macrophage lysosomal enzyme release of arachidonate metabolites, extracellular divalent cations and cyclic AMP (cAMP) which modulate secretion in other cell types. Lysosomal enzyme secretion induced by zymosan was accompanied by release of malondialdehyde (MDA), which is derived from arachidonic acid via prostaglandin synthase. Blockade of MDA formation, by aspirin or indomethacin, was associated with only a small inhibitory effect on lysosomal enzyme release by zymosan: arachidonate metabolites thus play only a minor role in mediating macrophage lysosomal enzyme release. Zymosan-induced secretion of lysosomal enzymes from macrophages did not require extracellular magnesium or calcium although release was enhanced by magnesium and inhibited by calcium. These effects may be related to an influence of the ions on phagocytosis. Elevation of intracellular divalent cation concentrations, by ionophore A23187, induced release of lysosomal enzymes but this was a result of cell lysis. Adenylate cyclase stimulants and dibutyryl cAMP produced slight inhibition of zymosan-induced lysosomal enzyme release. Aminophylline and papaverine caused more marked inhibition but their effects may be due to actions independent of phosphodiesterase inhibition. Our data indicate that arachidonate metabolites and cAMP do not play a major role in regulating zymosan-induced enzyme release from macrophages. Extracellular calcium and magnesium may modulate secretion but the role of intracellular divalent cations remains to be established. We conclude that macrophage lysosomal enzyme secretion is controlled by regulatory mechanisms different from those which control similar degranulation processes in other cell types.

Release of lysosomal enzymes in Tetrahymena: a Ca2+-dependent secretory process

1988 ◽  
Vol 90 (1) ◽  
pp. 167-171
Author(s):  
A. TIEDTKE ◽  
L. RASMUSSEN ◽  
J. FLORIN-CHRISTENSEN ◽  
M. FLORIN-CHRISTENSEN
Keyword(s):  
Lysosomal Enzyme ◽  
Isocitrate Dehydrogenase ◽  
Lysosomal Enzymes ◽  
Tetrahymena Thermophila ◽  
Secretory Process ◽  
Maximal Response ◽  
Ionophore A23187 ◽  
Enzyme Release ◽  
Fluorescence Measurements

The ciliate Tetrahymena thermophila releases lysosomal enzymes into nutrient and starvation media. We show here that this process occurs selectively, i.e. without leakage of cytoplasmic components, as indicated by lack of release of isocitrate dehydrogenase, a cytosolic enzyme with high activity in Tetrahymena. The role of intracellular Ca2+ in the process was also investigated. The Ca2+ ionophore A23187 has strong stimulatory effects on this release. Ionophore stimulation is maximal in the presence of extracellular Ca2+ but can occur also in its absence. Quin 2 fluorescence measurements indicate that intracellular Ca2+ increases in both cases. Mg2+ completely prevents the stimulatory effects of A23187. Ionomycin, another Ca2+ ionophore, also stimulates lysosomal enzyme release with a maximal response in the presence of extracellular Ca2+. Measurements of extracellular isocitrate dehydrogenase showed that ionophore-stimulated lysosomal enzyme release can take place without leakage of cytoplasmic components. The observations that divalent cation ionophores stimulate selective lysosomal enzyme release and that this effect is strongest in the presence of external Ca2+ indicate that this cation plays a crucial role in the control of this process in Tetrahymena. Together with other observations they support the view that a subpopulation of Tetrahymena lysosomes has properties like those of secretory vesicles.

scholarly journals HORMONAL CONTROL OF LYSOSOMAL ENZYME RELEASE FROM HUMAN NEUTROPHILS

1974 ◽  
Vol 139 (6) ◽  
pp. 1395-1414 ◽  
Author(s):  
L. J. Ignarro ◽  
T. F. Lint ◽  
W. J. George
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Lysosomal Enzyme ◽  
Lysosomal Enzymes ◽  
Hormonal Control ◽  
Human Neutrophils ◽  
Cell Contact ◽  
Enzyme Release ◽  
Lactate Dehydrogenase Activity ◽  
Particle Uptake

The purpose of this investigation was to examine the effects of autonomic neurohormones, cyclic nucleotides, and related agents on the immunologic discharge of lysosomal enzymes from, and phagocytosis by, purified human neutrophils. In order to discern the possible intracellular mechanisms by which certain neurohormones influence neutrophil function, the concentrations of cyclic AMP and cyclic GMP in neutrophils were assessed during cell contact with phagocytizable particles and autonomic agents. The model system employed for study was the interaction of purified human neutrophils with rheumatoid arthritic (RA) serum-treated zymosan particles at 37°C in a neutral, balanced salt solution containing glucose. Neutrophils ingested the particles and discharged ß-glucuronidase but not lactate dehydrogenase activity during 30 min of incubation. Treatment of zymosan particles with RA serum was more effective than treatment with normal serum with regard to the extent of both particle uptake and lysosomal enzyme release. During contact of neutrophils with RA serum-treated zymosan particles epinephrine, isoproterenol, and cyclic AMP inhibited both particle ingestion and ß-glucuronidase discharge. These actions of epinephrine were associated with a concomitant elevation of cyclic AMP levels. In contrast to the actions of catecholamines and cyclic AMP, acetylcholine and cyclic GMP accelerated lysosomal enzyme release without affecting particle uptake. The actions of acetylcholine were associated with a concomitant elevation of cyclic GMP levels. Increases in neutrophil levels of cyclic GMP but not of cyclic AMP were associated also with the discharge of ß-glucuronidase provoked by particles in the absence of added cholinergic agents. The data suggest that the immunologic release of lysosomal enzymes from human neutrophils can be regulated by autonomic neurohormones, perhaps via the selective formation of appropriate nucleotides.

scholarly journals Pertussis toxin inhibition of chemotactic factor-induced calcium mobilization and function in human polymorphonuclear leukocytes.

1985 ◽  
Vol 162 (1) ◽  
pp. 145-156 ◽  
Author(s):  
D W Goldman ◽  
F H Chang ◽  
L A Gifford ◽  
E J Goetzl ◽  
H R Bourne
Keyword(s):  
Pertussis Toxin ◽  
Lysosomal Enzyme ◽  
Polymorphonuclear Leukocytes ◽  
Regulatory Protein ◽  
Leukotriene B4 ◽  
Ionophore A23187 ◽  
Enzyme Release ◽  
Adp Ribosylation ◽  
Chemotactic Factors ◽  
Human Polymorphonuclear Leukocytes

Chemotactic factors stimulate a rapid increase in the cytosolic concentration of intracellular calcium ions ([Ca2+]in) in human polymorphonuclear leukocytes (PMNL), which may be an event that is critical to the expression of chemotaxis and other PMNL functions. Treatment of PMNL with pertussis toxin catalyzes ADP-ribosylation of a protein similar or identical to the inhibiting regulatory protein of adenylate cyclase, Gi, and suppresses the increase in [Ca2+]in elicited by leukotriene B4(LTB4) and formyl-methionyl-leucyl-phenylalanine. Chemotactic migration and lysosomal enzyme release elicited by chemotactic factors were inhibited by pertussis toxin with a concentration-dependence similar to that for inhibition of the increase in [Ca2+]in, without an effect on lysosomal enzyme release induced by the ionophore A23187 and phorbol myristate acetate. Activated pertussis toxin catalyzed the [32P]ADP-ribosylation of a 41 kD protein in homogenates of PMNL. The extent of [32P]ADP-ribosylation of this protein was reduced 59% by pretreatment of intact PMNL with pertussis toxin. Pertussis toxin selectively decreased the number of high-affinity receptors for LTB4 on PMNL by 60% without altering the number or binding properties of the low-affinity subset of receptors. Pertussis toxin modification of a membrane protein of PMNL analogous to Gi thus simultaneously alters chemotactic receptors and attenuates the changes in cytosolic calcium concentration and PMNL function caused by chemotactic factors.

Microtubule modulation of biliary excretion of endogenous and exogenous hepatic lysosomal constituents

1984 ◽  
Vol 246 (1) ◽  
pp. G8-G15 ◽  
Author(s):  
R. B. Sewell ◽  
S. S. Barham ◽  
A. R. Zinsmeister ◽  
N. F. LaRusso
Keyword(s):  
Lysosomal Enzyme ◽  
Biliary Excretion ◽  
Lysosomal Enzymes ◽  
Male Rats ◽  
Enzyme Secretion ◽  
Initial Increase ◽  
Acute Administration ◽  
Subsequent Decrease ◽  
Before And After

We tested the hypothesis that hepatocyte microtubules modulate the biliary excretion of endogenous and exogenous constituents of hepatocyte lysosomes. We collected bile via bile fistulas from male rats before and after acute administration of colchicine and vinblastine, agents known to bind to hepatocyte microtubules; rats were then killed and livers were homogenized for biochemical analyses or processed for electron microscopy. Colchicine caused biphasic, parallel alterations in the biliary excretion of three lysosomal enzymes compared with control rats given saline or lumicolchicine; a peak rise in enzyme outputs of approximately 175% at 45-60 min after colchicine administration was followed by a sustained fall to approximately 25% of control values, which persisted for 2-4 h. When hepatocyte lysosomes were prelabeled in vivo by administration of [3H]Triton WR-1339, a nonionic detergent that is sequestered in hepatic lysosomes, the biliary excretion of radiolabel in response to colchicine paralleled the biliary excretion of the three lysosomal enzymes. Vinblastine also induced a biphasic response in biliary lysosomal enzyme output that was similar to that produced by colchicine administration. Morphometric analysis of electron micrographs of rat livers demonstrated changes in the number of lysosomelike vesicles in the vicinity of bile canaliculi after colchicine and vinblastine administration; the initial increase in lysosomal enzyme secretion was associated with a significant decrease in the number of pericanalicular lysosomes after both agents, while the subsequent decrease in enzyme secretion coincided with an increase in the number of pericanalicular lysosomes after vinblastine.(ABSTRACT TRUNCATED AT 250 WORDS)

A study of kidney lysosomal acid phosphatase during compensatory renal hyperplasia in rats

1968 ◽  
Vol 46 (3) ◽  
pp. 499-502 ◽  
Author(s):  
B. M. Hegdekar
Keyword(s):  
Acid Phosphatase ◽  
Lysosomal Enzymes ◽  
Soluble Fraction ◽  
Female Rats ◽  
Enzyme Release ◽  
Lysosomal Fraction ◽  
Probable Role ◽  
Long Evans ◽  
Free Activity

Female rats of the Long-Evans hooded strain, 4–6 months old and weighing 275–300 grams, were subjected to unilateral nephrectomy and the acid phosphatase activity in the remaining kidney was studied at the end of 24, 48, 72 hours, and 8 days respectively. Most of the acid phosphatase was found in the particulate fraction in normal kidneys. The enzyme activity in the soluble fraction was found to have increased the second day after the operation, but decreased to the original level by the end of 72 hours. The free activity of the lysosomal fraction also increased by the end of second postoperative day. A change in the permeability of the lysosomal membrane before the enzyme release was observed. The probable role of lysosomal enzymes in the initiation of mitotic divisions during compensatory renal hyperplasia is discussed.

scholarly journals Specific alterations in levels of mannose 6-phosphorylated glycoproteins in different neuronal ceroid lipofuscinoses

1998 ◽  
Vol 334 (3) ◽  
pp. 547-551 ◽  
Author(s):  
David E. SLEAT ◽  
Istvan SOHAR ◽  
Premila S. PULLARKAT ◽  
Peter LOBEL ◽  
Raju K. PULLARKAT
Keyword(s):  
Lysosomal Enzyme ◽  
Neurodegenerative Disorders ◽  
Enzyme Activities ◽  
Lysosomal Enzymes ◽  
Vesicular Transport ◽  
Cell Types ◽  
Neuronal Ceroid Lipofuscinoses ◽  
Mannose 6 Phosphate ◽  
Normal Controls ◽  
Lysosomal Proteins

Mannose 6-phosphate (Man-6-P) is a carbohydrate modification that is generated on newly synthesized lysosomal proteins. This modification is specifically recognized by two Man-6-P receptors that direct the vesicular transport of the lysosomal enzymes from the Golgi to a prelysosomal compartment. The Man-6-P is rapidly removed in the lysosome of most cell types; however, in neurons the Man-6-P modification persists. In this study we have examined the spectrum of Man-6-P-containing glycoproteins in brain specimens from patients with different neuronal ceroid lipofuscinoses (NCLs), which are progressive neurodegenerative disorders with established links to defects in lysosomal catabolism. We find characteristic alterations in the Man-6-P glycoproteins in specimens from late-infantile (LINCL), juvenile (JNCL) and adult (ANCL) patients. Man-6-P glycoproteins in LINCL patients were similar to controls, with the exception that the band corresponding to CLN2, a recently identified lysosomal enzyme whose deficiency results in this disease, was absent. In an ANCL patient, two Man-6-P glycoproteins were elevated in comparison with normal controls, suggesting that this disease also results from a perturbation in lysosomal hydrolysis. In JNCL, total levels of Man-6-P glycoproteins were 7-fold those of controls. In general this was reflected by increased lysosomal enzyme activities in JNCL but three Man-6-P glycoproteins were elevated to an even greater degree. These are CLN2 and the unidentified proteins that are also highly elevated in the ANCL.

scholarly journals The role of divalent cations in the regulation of microtubule assembly. In vivo studies on microtubules of the heliozoan axopodium using the ionophore A23187.

1976 ◽  
Vol 70 (3) ◽  
pp. 527-540 ◽  
Author(s):  
M Schliwa
Keyword(s):  
Divalent Cations ◽  
Light And Electron Microscopy ◽  
Microtubule Assembly ◽  
In Vivo Studies ◽  
Ionophore A23187 ◽  
Low Concentrations ◽  
Microtubule Formation

Low concentrations of calcium and magnesium ions have been shown to influence microtubule assembly in vitro. To test whether these cations also have an effect on microtubules in vivo, specimens of Actinosphaerium eichhorni were exposed to different concentrations of Ca++ and Mg++ and the divalent cation ionophore A23187. Experimental degradation and reformation of axopodia were studied by light and electron microscopy. In the presence of Ca++ and the ionophore axopodia gradually shorten, the rate of shortening depending on the concentrations of Ca++ and the ionophore used. Retraction of axopodia was observed with a concentration of Ca++ as low as 0.01 mM. After transfer to a Ca++-free solution containing EGTA, axopodia re-extend; the initial length is reached after about 2 h. Likewise, reformation of axopodia of cold-treated organisms is observed only in solutions of EGTA or Mg++, whereas it is completely inhibited in a Ca++ solution. Electron microscope studies demonstrate degradation of the axonemal microtubular array in organisms treated with Ca++ and A23187. No alteration was observed in organisms treated with Mg++ or EGTA plus ionophore. The results suggest that, in the presence of the ionophore, formation of axonemal microtubules can be regulated by varying the Ca++ concentration in the medium. Since A23187 tends to equilibrate the concentrations of divalent cations between external medium and cell interior, it is likely that microtubule formation invivo is influenced by micromolar concentrations of Ca++. These concentrations are low enough to be of physiological significance for a role in the regulation of microtubule assembly in vivo.

The Induction of Lysosomal Enzyme Release from Leucocytes of Normal and Emphysematous Subjects and the Effects of Tobacco Smoke upon Phagocytosis

1980 ◽  
Vol 58 (5) ◽  
pp. 403-409 ◽  
Author(s):  
D. C. S. Hutchison ◽  
R. Desai ◽  
D. Bellamy ◽  
H. Baum
Keyword(s):  
Cigarette Smoke ◽  
Lysosomal Enzyme ◽  
Lysosomal Enzymes ◽  
Soluble Fraction ◽  
Normal Subjects ◽  
Polymorphonuclear Leucocytes ◽  
Enzyme Release ◽  
Elastic Tissue ◽  
Latex Particles ◽  
Respiratory Inhibitor

1. The lysosomal enzymes of circulating polymorphonuclear leucocytes contain a potent elastase; release of this enzyme within the lung is thought to be responsible for the destruction of elastic tissue in pulmonary emphysema. 2. The release of lysosomal enzymes from blood leucocytes of normal and emphysematous subjects during phagocytosis of particulate material was studied In vitro. Acid phosphatase and acid ribonuclease were used as markers of lysosomal enzyme release, no sufficiently sensitive assay for elastase being available. Cigarette smoke was separated into ‘particulate’ and ‘soluble’ fractions. In a preliminary study, the particulate fraction stimulated enzyme release; in the experiments reported here, latex particles were used to produce this effect. 3. Approximately one-third of the total lysosomal enzyme content was released to the exterior of the cell during phagocytosis of latex particles. In this respect there was no difference between normal and emphysematous subjects. 4. The effects of the non-particulate soluble fraction of cigarette smoke on phagocytosis-induced enzyme release were studied. This fraction inhibited enzyme release from polymorphonuclear leucocytes of normal subjects but not from those of emphysematous patients. When the ‘cigarette-smoke solution’ was replaced by the respiratory inhibitor, antimycin A, a similar inhibition of enzyme release occurred. The inhibition of phagocytosis in cells of normal subjects is presumed to be due to a respiratory inhibitor such as carbon monoxide in the soluble fraction of the smoke. We postulate that the polymorphonuclear leucocytes of emphysematous patients are adapted to hypoxic conditions so that inhibition of enzyme release does not occur.

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