scholarly journals Ceramide Inhibits IgG-Dependent Phagocytosis in Human Polymorphonuclear Leukocytes

Blood ◽  
1997 ◽  
Vol 89 (6) ◽  
pp. 2139-2147 ◽  
Author(s):  
Suzanne J. Suchard ◽  
Vania Hinkovska-Galcheva ◽  
Pamela J. Mansfield ◽  
Laurence A. Boxer ◽  
James A. Shayman
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Cell Types ◽  
Short Chain ◽  
Sphingolipid Metabolism ◽  
Sphingomyelin Cycle ◽  
Intracellular Target ◽  
Human Polymorphonuclear Leukocytes ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Ceramide Production

Abstract Ceramide is a product of agonist-induced sphingolipid metabolism in several cell types, including polymorphonuclear leukocytes (PMNs). In adherent PMNs, the kinetics of ceramide production correspond with the termination of fMLP-stimulated H2O2 release. Furthermore, short chain ceramides inhibit fMLP-mediated H2O2 release in adherent PMNs. In the present study, we investigated the effects of short chain ceramides and sphingoid bases on phagocytosis of IgG-opsonized erythrocytes (EIgG) by suspended PMNs activated with fMLP. N-Acetylsphingosine, N-acetylphytosphingosine, phytosphingosine, sphingosine, and dihydrosphingosine, but not N-acetyldihydrosphingosine, inhibited phagocytosis of EIgG. In contrast, these same lipids did not inhibit fMLP-mediated chemotaxis. Endogenous ceramide levels increased within the first few minutes of phagocytosis, with a significant (P < .05) accumulation by 30 minutes, the time by which phagocytosis was terminated. Neutral sphingomyelinase activity paralleled the increase in ceramide, consistent with the generation of ceramide by the hydrolysis of sphingomyelin. The N-acetyl-conjugated sphingols (C2 ceramides) blocked phosphatidylethanol formation indicating that phospholipase D (PLD) is an intracellular target of ceramide action. These data suggest that ceramides, generated through activation of the sphingomyelin cycle, act as negative regulators of FcγR-mediated phagocytosis.

scholarly journals Uptake and intracellular activity of NM394, a new quinolone, in human polymorphonuclear leukocytes.

1996 ◽  
Vol 40 (3) ◽  
pp. 739-742 ◽  
Author(s):  
M Ozaki ◽  
K Komori ◽  
M Matsuda ◽  
R Yamaguchi ◽  
T Honmura ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infection ◽  
Polymorphonuclear Leukocytes ◽  
Concentration Ratio ◽  
Extracellular Concentration ◽  
Intracellular Activity ◽  
Subsequent Elution ◽  
Active Transport System ◽  
Human Polymorphonuclear Leukocytes ◽  
Kinetics Of

The uptake of NM394, a new quinolone, by and its subsequent elution from human polymorphonuclear leukocytes were studied and compared with those of ofloxacin and ciprofloxacin. The kinetics of the uptake of NM394 was similar to that of ciprofloxacin. The maximum intracellular-to-extracellular concentration ratio was 12.3, compared with 8.6 for ciprofloxacin and 4.9 for ofloxacin at the extracellular concentration of 20 micrograms/ml. The elution of NM394 from human polymorphonuclear leukocytes occurs relatively slowly; 5 min after the removal of extracellular NM394, nearly 100% still remained in polymorphonuclear leukocytes, compared with ofloxacin, which was so rapidly eluted that only 12% remained. The uptake of NM394 was significantly decreased at 4 degrees C and by the presence of NaCN but was not affected by the presence of L-glycine, L-leucine, L-serine, adenosine, or NaF. NM394 showed intracellular activity at a concentration of 0.1 microgram/ml that significantly reduced the number of phagocytosed Pseudomonas aeruginosa cells with 2 h of incubation. These results suggest that uptake of NM394 by human polymorphonuclear leukocytes occurs via an active transport system differing from that of ofloxacin, whose uptake is affected by the presence of L-glycine and L-leucine, and that once accumulated, NM394 remains intracellularly active and participates in protection against bacterial infection.

scholarly journals Thymosin beta 4 sequesters the majority of G-actin in resting human polymorphonuclear leukocytes.

1992 ◽  
Vol 119 (5) ◽  
pp. 1261-1270 ◽  
Author(s):  
L Cassimeris ◽  
D Safer ◽  
V T Nachmias ◽  
S H Zigmond
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Actin Polymerization ◽  
Large Fraction ◽  
Reverse Phase Hplc ◽  
Thymosin Beta 4 ◽  
Rapid Changes ◽  
Human Pmns ◽  
Human Polymorphonuclear Leukocytes ◽  
Kinetics Of

Thymosin beta 4 (T beta 4), a 5-kD peptide which binds G-actin and inhibits its polymerization (Safer, D., M. Elzinga, and V. T. Nachmias. 1991. J. Biol. Chem. 266:4029-4032), appears to be the major G-actin sequestering protein in human PMNs. In support of a previous study by Hannappel, E., and M. Van Kampen (1987. J. Chromatography. 397:279-285), we find that T beta 4 is an abundant peptide in these cells. By reverse phase HPLC of perchloric acid supernatants, human PMNs contain approximately 169 fg/cell +/- 90 fg/cell (SD), corresponding to a cytoplasmic concentration of approximately 149 +/- 80.5 microM. On non-denaturing polyacrylamide gels, a large fraction of G-actin in supernatants prepared from resting PMNs has a mobility similar to the G-actin/T beta 4 complex. Chemoattractant stimulation of PMNs results in a decrease in this G-actin/T beta 4 complex. To determine whether chemoattractant induced actin polymerization results from an inactivation of T beta 4, the G-actin sequestering activity of supernatants prepared from resting and chemoattractant stimulated cells was measured by comparing the rates of pyrenyl-actin polymerization from filament pointed ends. Pyrenyl actin polymerization was inhibited to a greater extent in supernatants from stimulated cells and these results are qualitatively consistent with T beta 4 being released as G-actin polymerizes, with no chemoattractant-induced change in its affinity for G-actin. The kinetics of bovine spleen T beta 4 binding to muscle pyrenyl G-actin are sufficiently rapid to accommodate the rapid changes in actin polymerization and depolymerization observed in vivo in response to chemoattractant addition and removal.

Activation of a Plasma Membrane–Associated Neutral Sphingomyelinase and Concomitant Ceramide Accumulation During IgG-Dependent Phagocytosis in Human Polymorphonuclear Leukocytes

Blood ◽  
1998 ◽  
Vol 91 (12) ◽  
pp. 4761-4769 ◽  
Author(s):  
Vania Hinkovska-Galcheva ◽  
Lars Kjeldsen ◽  
Pamela J. Mansfield ◽  
Laurence A. Boxer ◽  
James A. Shayman ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Polymorphonuclear Leukocytes ◽  
Fold Increase ◽  
Acid Sphingomyelinase ◽  
Functional Responses ◽  
Neutral Sphingomyelinase ◽  
Sphingomyelin Cycle ◽  
Human Pmns ◽  
Ceramide Accumulation ◽  
Human Polymorphonuclear Leukocytes

Abstract The sphingomyelin cycle, which plays an important role in regulation of cell growth, differentiation, and apoptosis, involves the formation of ceramide by the action of a membrane-associated, Mg2+-dependent, neutral sphingomyelinase and/or a lysosomal acid sphingomyelinase. In human polymorphonuclear leukocytes (PMNs), ceramide production correlates with and plays a role in the regulation of functional responses such as oxidant release and Fcγ receptor-mediated phagocytosis. To increase our understanding of the sphingomyelin cycle in human PMNs, the cellular location of neutral and acid sphingomyelinases was investigated in resting, formylmethionylleucylphenylalanine (FMLP)-activated, and FMLP-activated PMNs engaged in phagocytosis. In resting PMNs, a Mg2+-dependent, neutral sphingomyelinase was the predominant activity and was localized to the plasma membrane fractions along with the majority of ceramide. Upon FMLP-activation, there was a 1.9-fold increase in this neutral, Mg2+-dependent sphingomyelinase activity, which increased to 2.7-fold subsequent to phagocytosis of IgG opsonized targets. This increase in sphingomyelinase activity was restricted to the plasma membrane fractions, which were also the site of increased ceramide levels. Phospholipase D (PLD) activity, which is a target of ceramide action and is required for phagocytosis, was also found primarily in the plasma membrane fractions of FMLP-activated and phagocytosing PMNs. Our findings indicate that in human PMNs engaged in phagocytosis, the sphingomyelin cycle is restricted to the plasma membrane where intracellular targets of ceramide action, such as PLD, are localized.

Presence of nonesterified and acylcarnitine in human polymorphonuclear leukocytes and mononuclear cells.

1987 ◽  
Vol 33 (4) ◽  
pp. 533-535 ◽  
Author(s):  
K Katrib ◽  
H A Adlouni ◽  
G Férard
Keyword(s):  
Perchloric Acid ◽  
Whole Blood ◽  
Blood Cells ◽  
Polymorphonuclear Leukocytes ◽  
Mononuclear Cells ◽  
Short Chain ◽  
The Mean ◽  
Total Carnitine ◽  
Human Polymorphonuclear Leukocytes ◽  
Long Chain

Abstract We demonstrate the presence of nonesterified carnitine and acylcarnitine in leukocytes, but not in erythrocytes, from 16 healthy adults. After carefully separating the different kinds of blood cells we measured significant amounts of nonesterified carnitine and acylcarnitine in polymorphonuclear leukocytes (28.5 +/- 6.1 and 18.5 +/- 6.3 mumol/10(9) cells) and mononuclear cells (25.4 +/- 5.2 and 14.8 +/- 4.5 mumol/10(9) cells). We also measured nonesterified carnitine, long-chain acylcarnitine, and short-chain acylcarnitine in plasma after fractionation with perchloric acid and obtained the following values (mean +/- SD): 41.4 +/- 2.6, 3.9 +/- 1.2, and 6.0 +/- 1.6 mumol/L, respectively. The mean percentages of total carnitine (n = 6) in polymorphonuclear leukocytes, mononuclear cells, and plasma were approximately 62%, 27%, and 13% of whole-blood carnitine, respectively (mean recovery was 102%). The percentage of acylated carnitine was 37% in leukocytes, as compared with 19% in plasma.

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