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.

scholarly journals Secretion of plasminogen activator by human polymorphonuclear leukocytes. Modulation by glucocorticoids and other effectors.

1977 ◽  
Vol 146 (6) ◽  
pp. 1693-1706 ◽  
Author(s):  
A Granelli-Piperno ◽  
J D Vassalli ◽  
E Reich
Keyword(s):  
Plasminogen Activator ◽  
Polymorphonuclear Leukocytes ◽  
Response Pattern ◽  
Actinomycin D ◽  
Lytic Enzymes ◽  
Con A ◽  
Low Concentrations ◽  
Human Pmns ◽  
Human Polymorphonuclear Leukocytes

Purified human PMNs secrete plasminogen activator. This secretion is stimulated by Con A and low concentrations of PMA, and is inhibited by low concentrations of glucocorticoids, and by cAMP, actinomycin D, and cycloheximide. In contrast, the release of granule-bound enzymes, such as elastase, is achieved only at higher concentrations of PMA, and is not affected by any of the inhibitors that block plasminogen activator production. These results show that the production of plasminogen activatory by PMNs is controlled by agents that affect inflammations, and that this control is not shared by other lytic enzymes known to be associated with these cells. This suggests a particular role for plasminogen activator in the response pattern of PMNs and also supports the concept, previously developed for macrophages, that the secretion of this enzyme is correlated with cell migration in vivo.

scholarly journals The bulk of unpolymerized actin in Xenopus egg extracts is ATP-bound.

1995 ◽  
Vol 6 (2) ◽  
pp. 227-236 ◽  
Author(s):  
J Rosenblatt ◽  
P Peluso ◽  
T J Mitchison
Keyword(s):  
Actin Polymerization ◽  
Critical Concentration ◽  
Large Fraction ◽  
Nucleotide Exchange ◽  
Chromatography Analysis ◽  
Thymosin Beta 4 ◽  
Egg Extracts ◽  
Xenopus Egg ◽  
Xenopus Egg Extracts

Non-muscle cells contain 15-500 microM actin, a large fraction of which is unpolymerized. Thus, the concentration of unpolymerized actin is well above the critical concentration for polymerization in vitro (0.2 microM). This fraction of actin could be prevented from polymerization by being ADP bound (therefore less favored to polymerize) or by being ATP bound and sequestered by a protein such as thymosin beta 4, or both. We isolated the unpolymerized actin from Xenopus egg extracts using immobilized DNase 1 and assayed the bound nucleotide. High-pressure liquid chromatography analysis showed that the bulk of soluble actin is ATP bound. Analysis of actin-bound nucleotide exchange rates suggested the existence of two pools of unpolymerized actin, one of which exchanges nucleotide relatively rapidly and another that apparently does not exchange. Native gel electrophoresis of Xenopus egg extracts demonstrated that most of the soluble actin exists in complexes with other proteins, one of which might be thymosin beta 4. These results are consistent with actin polymerization being controlled by the sequestration and release of ATP-bound actin, and argue against nucleotide exchange playing a major role in regulating actin polymerization.

scholarly journals Mechanisms responsible for F-actin stabilization after lysis of polymorphonuclear leukocytes.

1992 ◽  
Vol 116 (5) ◽  
pp. 1123-1134 ◽  
Author(s):  
M L Cano ◽  
L Cassimeris ◽  
M Fechheimer ◽  
S H Zigmond
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Actin Polymerization ◽  
Cell Movement ◽  
Actin Binding ◽  
Cross Linking ◽  
Macromolecular Complex ◽  
Actin Depolymerization ◽  
Gravitational Forces ◽  
End Capping

While actin polymerization and depolymerization are both essential for cell movement, few studies have focused on actin depolymerization. In vivo, depolymerization can occur exceedingly rapidly and in a spatially defined manner: the F-actin in the lamellipodia depolymerizes in 30 s after chemoattractant removal (Cassimeris, L., H. McNeill, and S. H. Zigmond. 1990. J. Cell Biol. 110:1067-1075). To begin to understand the regulation of F-actin depolymerization, we have examined F-actin depolymerization in lysates of polymorphonuclear leukocytes (PMNs). Surprisingly, much of the cell F-actin, measured with a TRITC-phalloidin-binding assay, was stable after lysis in a physiological salt buffer (0.15 M KCl): approximately 50% of the F-actin did not depolymerize even after 18 h. This stable F-actin included lamellar F-actin which could still be visualized one hour after lysis by staining with TRITC-phalloidin and by EM. We investigated the basis for this stability. In lysates with cell concentrations greater than 10(7) cells/ml, sufficient globular actin (G-actin) was present to result in a net increase in F-actin. However, the F-actin stability was not solely because of the presence of free G-actin since addition of DNase I to the lysate did not increase the F-actin loss. Nor did it appear to be because of barbed end capping factors since cell lysates provided sites for barbed end polymerization of exogenous added actin. The stable F-actin existed in a macromolecular complex that pelleted at low gravitational forces. Increasing the salt concentration of the lysis buffer decreased the amount of F-actin that pelleted at low gravitational forces and increased the amount of F-actin that depolymerized. Various actin-binding and cross-linking proteins such as tropomyosin, alpha-actinin, and actin-binding protein pelleted with the stable F-actin. In addition, we found that alpha-actinin, a filament cross-linking protein, inhibited the rate of pyrenyl F-actin depolymerization. These results suggested that actin cross-linking proteins may contribute to the stability of cellular actin after lysis. The activity of crosslinkers may be regulated in vivo to allow rapid turnover of lamellipodia F-actin.

Human Polymorphonuclear Leukocytes Derived from Chronically Inflamed Tissue Express Inflammatory Cytokines in Vivo

1994 ◽  
Vol 156 (2) ◽  
pp. 296-309 ◽  
Author(s):  
Osamu Takeichi ◽  
Ichiro Saito ◽  
Tamotsu Tsurumachi ◽  
Tsuyoshi Saito ◽  
Itaru Moro
Keyword(s):  
Inflammatory Cytokines ◽  
Polymorphonuclear Leukocytes ◽  
Human Polymorphonuclear Leukocytes ◽  
Inflamed Tissue

scholarly journals Entry of Sanfetrinem into Human Polymorphonuclear Granulocytes and Its Cell-Associated Activity against Intracellular, Penicillin-Resistant Streptococcus pneumoniae

1998 ◽  
Vol 42 (7) ◽  
pp. 1745-1750 ◽  
Author(s):  
Anna Maria Cuffini ◽  
Vivian Tullio ◽  
Alessandro Bonino ◽  
Alessandra Allocco ◽  
Angela Ianni Palarchio ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Polymorphonuclear Leukocytes ◽  
Environmental Temperature ◽  
Metabolic Inhibitor ◽  
Intracellular Pathogens ◽  
New Class ◽  
Polymorphonuclear Granulocytes ◽  
Human Pmns ◽  
Energy Dependent ◽  
Human Polymorphonuclear Leukocytes

ABSTRACT The entry of antibiotics into phagocytes is necessary for activity against intracellular pathogens. The ability of sanfetrinem, the first member of a new class of antibiotics, to penetrate human polymorphonuclear granulocytes and its consequences upon subsequent phagocytosis and killing of ingested penicillin-resistantStreptococcus pneumoniae have been evaluated. Sanfetrinem penetrated into human polymorphonuclear leukocytes (PMNs) at all concentrations tested, with cellular concentration/extracellular concentration ratios of 6.6 to 5.03 and 4.21 when sanfetrinem was used at 0.25 to 0.5 and 1 μg/ml, respectively, within 30 min of incubation. The uptake was complete within 5 min and was not energy dependent, since it was not affected by cell viability, environmental temperature, or the addition of a metabolic inhibitor. At a concentration of one-half the MIC, sanfetrinem significantly enhanced human PMN phagocytosis and increased intracellular bactericidal activity against penicillin-resistant S. pneumoniae. Following preexposure of PMNs to a concentration of one-half the MIC of sanfetrinem, there was a significant increase in both phagocytosis and killing compared with that for the controls, indicating the ability of sanfetrinem to interact with biological membranes and remain active within PMNs. Preexposure of streptococci to sanfetrinem made penicillin-resistant S. pneumoniae more susceptible to the bactericidal mechanisms of human PMNs than untreated organisms.

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.

Design and characterization of a cleavage-resistant Annexin A1 mutant to control inflammation in the microvasculature

Blood ◽  
2010 ◽  
Vol 116 (20) ◽  
pp. 4288-4296 ◽  
Author(s):  
Magali Pederzoli-Ribeil ◽  
Francesco Maione ◽  
Dianne Cooper ◽  
Adam Al-Kashi ◽  
Jesmond Dalli ◽  
...  
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Early Stage ◽  
Leukocyte Adhesion ◽  
Formyl Peptide Receptor ◽  
Annexin A1 ◽  
Formyl Peptide ◽  
Anti Inflammatory ◽  
Human Polymorphonuclear Leukocytes

Abstract Human polymorphonuclear leukocytes adhesion to endothelial cells during the early stage of inflammation leads to cell surface externalization of Annexin A1 (AnxA1), an effector of endogenous anti-inflammation. The antiadhesive properties of AnxA1 become operative to finely tune polymorphonuclear leukocytes transmigration to the site of inflammation. Membrane bound proteinase 3 (PR3) plays a key role in this microenvironment by cleaving the N terminus bioactive domain of AnxA1. In the present study, we generated a PR3-resistant human recombinant AnxA1—named superAnxA1 (SAnxA1)—and tested its in vitro and in vivo properties in comparison to the parental protein. SAnxA1 bound and activated formyl peptide receptor 2 in a similar way as the parental protein, while showing a resistance to cleavage by recombinant PR3. SAnxA1 retained anti-inflammatory activities in the murine inflamed microcirculation (leukocyte adhesion being the readout) and in skin trafficking model. When longer-lasting models of inflammation were applied, SAnxA1 displayed stronger anti-inflammatory effect over time compared with the parental protein. Together these results indicate that AnxA1 cleavage is an important process during neutrophilic inflammation and that controlling the balance between AnxA1/PR3 activities might represent a promising avenue for the discovery of novel therapeutic approaches.

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