Anti-phospholipase C antibodies inhibit the lectin-induced proliferation of human lymphocytes

1987 ◽  
Vol 7 (9) ◽  
pp. 731-736 ◽  
Author(s):  
I. I. Moraru ◽  
Mioara Manciulea ◽  
Anca Cǎlugǎru ◽  
Gr. Ghyka ◽  
L. M. Popescu
Keyword(s):  
Phospholipase C ◽  
Human Peripheral Blood ◽  
Human Lymphocytes ◽  
Blood Leukocytes ◽  
Novel Approach ◽  
Versus Protein ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Membrane Bound

A novel approach was used to assess the role of phosphoinositide hydrolysis in the mitogenic action of phytohemagglutinin (PHA) or concanavalin A (ConA). The treatment of human peripheral blood leukocytes (PBL) with monospecific antibodies against phospholipase C (PLC) produced a dose-dependent inhibition (up to 100%) of PHA (10 μg/ml) or ConA (25 μg/ml) proliferative effects. Thus, the activation of membrane-bound PLC is a sine-qua-non condition for lectin-induced proliferation of T lymphocytes. The key-role of PLC versus protein kinase C (PKC) is stressed by the fact that the inhibition of PKC with Hidaka's compound H-7 (40 μM) produced only a partial blockade (about 25%) of lectin mitogenic effect.

Investigation on the antibacterial activity of electronic cigarette liquids (ECLs): a proof of concept study

2020 ◽  
Vol 21 ◽  
Author(s):  
Virginia Fuochi ◽  
Massimo Caruso ◽  
Rosalia Emma ◽  
Aldo Stivala ◽  
Riccardo Polosa ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Species ◽  
A549 Cells ◽  
Bactericidal Effect ◽  
Minimal Bactericidal Concentration ◽  
Viability Assay ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Background: The key ingredients of e-cigarettes liquid are commonly propane-1,2-diol (also called propylene glycol) and propane-1,2,3-triol (vegetal glycerol) and their antimicrobial effects are already established. The nicotine and flavors which are often present in e-liquids can interfere with the growth of some microorganisms. Objective: The effect of the combining these elements in e-liquids is unknown. The aim of the study was to investigate the possible effects of these liquids on bacterial growth in the presence or absence of nicotine and flavors. Methods: Susceptibilities of pathogenic strains (Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis and Sarcina lutea) were studied by means of a multidisciplinary approach. Cell viability and antioxidant assays were also evaluated. Results: All e-liquids investigated showed antibacterial activity against at least one pathogenic strain. A higher activity was correlated to the presence of flavors and nicotine. Discussion: In most cases the value of minimal bactericidal concentration is equal to the value of minimal inhibitory concentration showing that these substances have a bactericidal effect. This effect was observed in concentrations up to 6.25% v/v. Antioxidant activity was also correlated to presence of flavors. Over time, the viability assay in human epithelial lung A549 cells showed a dose-dependent inhibition of cell growth. Conclusion: Our results have shown that flavors considerably enhance the antibacterial activity of propane-1,2-diol and propane-1,2,3-triol. This study provides important evidence that should be taken into consideration in further investigative approaches, to clarify the different sensitivity of the various bacterial species to e-liquids, including the respiratory microbiota, to highlight the possible role of flavors and nicotine.

scholarly journals Control of hsp70 RNA levels in human lymphocytes.

1987 ◽  
Vol 104 (2) ◽  
pp. 183-187 ◽  
Author(s):  
L Kaczmarek ◽  
B Calabretta ◽  
H T Kao ◽  
N Heintz ◽  
J Nevins ◽  
...  
Keyword(s):  
Culture Medium ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Human Lymphocytes ◽  
Peripheral Blood Mononuclear ◽  
Growth State ◽  
Steady State Levels ◽  
Rna Blots

The expression of a hsp70 gene in human cells has previously been shown to be related to the growth state of the cells. As an alternative to in vitro synchronization procedures, we have measured steady-state levels of the RNA for a heat-shock protein 70 (hsp70) in human peripheral blood mononuclear cells (PBMC) that are naturally quiescent in a G0 state. The probe used recognized, on RNA blots, one single band. The levels of this hsp70 RNA are elevated in circulating PBMC and decrease when the cells are incubated with serum, or phytohemagglutinin, or simply when they are incubated in culture medium. The levels of hsp70 RNA decrease within 30 min after in vitro culture, and are accompanied by an increase in the levels of c-fos RNA. These findings, together with other recent reports in the literature, suggest a possible role of the hsp70 proteins in the regulation of cell growth.

scholarly journals Intracellular Sodium Regulates Opioid Signalling in Peripheral Neurons

2017 ◽  
Author(s):  
Alexandros H. Kanellopoulos ◽  
Jing Zhao ◽  
Edward C. Emery ◽  
John N Wood
Keyword(s):  
Protein Kinase ◽  
Sodium Channel ◽  
Protein Kinase A ◽  
Fold Increase ◽  
Intracellular Sodium ◽  
Peripheral Neurons ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Kinase A

AbstractOpioid receptors signal more effectively in sensory neurons from pain-free mice lacking the voltagegated sodium channel Nav1.7. Type-A GPCRs are known to be regulated through a specific sodium binding site, the occupancy of which diminishes agonist binding. We have used an electrophysiological assay of Protein Kinase A activity to examine the role of intracellular sodium on opioid signalling. Phosphorylation of sodium channel Nav1.8 by activation of Protein Kinase A with db-cAMP is unaffected by altered intracellular sodium. By contrast, there is a dose-dependent inhibition of fentanyl action on Nav1.8 currents when intracellular sodium is increased from 0 mM to 20 mM. Fentanyl shows a 50% loss of activity and 80-fold increase in EC50 with 20 mM intracellular sodium. These data demonstrate that altered intracellular sodium levels modulate opioid receptor signalling.

scholarly journals The effect of growth hormone on the function of phagocytic human blood cells

2000 ◽  
Vol 46 (3) ◽  
pp. 25-28
Author(s):  
B. A. Bakhmetev ◽  
N. S. Likhacheva
Keyword(s):  
Growth Hormone ◽  
Blood Cells ◽  
Phagocytic Activity ◽  
Superoxide Anion ◽  
Human Peripheral Blood ◽  
Human Lymphocytes ◽  
Blood Leukocytes ◽  
Somatotropic Hormone ◽  
Hormone Effect

Effects of somatotropic hormone in different concentrations on the phagocytic activity of various populations of human lymphocytes and production of superoxide anion were analyzed in vitro. Blood cells were incubated in medium 199 with various hormone concentrations for 1 h at 37°C. Besides the traditional general parameters of phagocytosis, the counts of eosinophils, neutrophils, monocytes phagocytizing and not phagocytizing sheep red cells (SRC) were evaluated with regard to their activity (number of phagocytosed SRC) in the total pool of phagocytes (sum of all phagocytizing cells of different activity per mm3 blood). The spontaneous and zymosan-stimulated levels of superoxide anion were evaluated in the nitroblue tetrasolium reduction test. Addition of somatotropic hormone stimulated the total phagocytic activity of human leukocytes by activating al! types of phagocytes, but the hormone effect was different for different cells. Growth hormone exerted the greatest stimulating effect on monocytes, increasing 3-5-fold their role in total phagocytosis, in comparison with the control. Addition of growth hormone increased zymosan-stimulated production of superoxide anion but did not change its spontaneous level. The results indicate the probability and demonstrate the direction of the immediate effect of growth hormone on the functions of some populations of human peripheral blood leukocytes.

scholarly journals The T-cell CD2 determinant mediates inhibition of erythropoiesis by the lymphokine cascade

Blood ◽  
1988 ◽  
Vol 72 (2) ◽  
pp. 770-775 ◽  
Author(s):  
S Burdach ◽  
M Shatsky ◽  
B Wagenhorst ◽  
L Levitt
Keyword(s):  
T Cells ◽  
T Cell ◽  
Interleukin 2 ◽  
Receptor Expression ◽  
Isotype Control ◽  
Isotype Control Antibody ◽  
Dependent Inhibition ◽  
Neutralizing Monoclonal Antibody ◽  
Dose Dependent Inhibition

Abstract We examined the role of the T-cell antigen CD2 in the regulation of erythropoiesis by the lymphokine cascade. T-cell interleukin-2 (IL-2) receptors (p55) were induced via triggering of the antigen receptor- associated CD3 epitope. Before CD3 triggering T cells were preincubated with a CD2-blocking (Leu-5b) or isotype control antibody. T-cell pellets were employed during incubation to facilitate interaction between T-cell LFA-3 and CD2. CD2 blockade caused a 66% to 79% inhibition of p55 expression after three to six days of culture with IL- 2. Next we assessed the effect of CD2 blockade on IL-2. Next we assessed the effect of CD2 blockade on IL-2-induced inhibition of BFU-E in autologous cocultures containing CD3-triggered T cells. IL-2 caused a dose-dependent inhibition (52% to 92%) of BFU-E in the presence but not in the absence of CD3-triggered T cells. T-cell CD2 blockade prior to CD3 triggering caused a 65% to 87% abrogation of IL-2-induced inhibition of BFU-E at 10 to 10(2) U/mL IL-2. Preincubation of CD3- triggered T cells with isotype control antibody had no effect on IL-2- induced erythroid inhibition. Day 3 supernatants from CD3-triggered T cells or CD2-blocked, CD3-triggered T cells established in the presence of IL-2 were next assessed for modulation of BFU-E. CD3-triggered T- cell supernatants caused a 77% +/- 9% inhibition of BFU-E. Blockade of CD2 caused a 95% abrogation of T-cell-mediated BFU-E inhibition. In addition, CD2 blockade reduced interferon-gamma (IF gamma) release (84 to 128 U/mL) from CD3-triggered T cells by 81% at day 3 of culture. In control experiments, the addition of IF gamma-neutralizing monoclonal antibody to CD3-triggered T-cell supernatant established in the presence of IL-2 caused 75% abrogation of IL-2 inhibition of BFU-E. We conclude that blockade of the CD2 T-cell determinant induces down modulation of (a) T-cell p55 IL-2 receptor expression, (b) IL-2-induced inhibition of BFU-E, and (c) IL-2-induced marrow T-cell IF gamma release. These data suggest that the T-cell CD2 determinant can exert a regulatory effect on the control of erythropoiesis by the lymphokine cascade.

Prejunctional inhibition of vasoactive intestinal peptide release

1987 ◽  
Vol 253 (1) ◽  
pp. G7-G12 ◽  
Author(s):  
J. R. Grider ◽  
G. M. Makhlouf
Keyword(s):  
Vasoactive Intestinal Peptide ◽  
Muscle Relaxation ◽  
Dependent Manner ◽  
Basal Tone ◽  
Peptide Release ◽  
Dependent Inhibition ◽  
Motor Nerves ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

The role of vasoactive intestinal peptide (VIP) and its homologue, peptide histidine isoleucine (PHI), as neurotransmitters of inhibitory motor nerves of the gut, were examined in strips of guinea pig taenia coli and gastric fundic muscle. The stoichiometry of VIP release and muscle relaxation was determined in the presence and absence of the bee venom peptide, apamin, and the existence of prejunctional VIP/PHI receptors capable of regulating VIP/PHI release was explored. In both types of muscle, relaxation induced by field stimulation was proportional to the amount of VIP released. Apamin inhibited relaxation and VIP release in a dose-dependent manner: maximal relaxation was inhibited by 85–96% at 10(-7)-10(-6) M apamin. Analysis of residual responses showed that apamin did not affect the stoichiometry of VIP release and muscle relaxation. Because apamin had no effect on basal tone or on relaxation induced by exogenous VIP, its effect on neurally induced relaxation was attributed to inhibition of VIP release. Both secretin and PHI inhibited neurally induced VIP release in the two types of muscle. At the optimal concentration of 10(-7) M, secretin inhibited VIP release by 52%, whereas the closer neural homologue, PHI, abolished VIP release. The dose-dependent inhibition of VIP release by PHI, which is cosynthesized and coreleased with VIP, indicates the existence of prejunctional inhibitory VIP/PHI autoreceptors capable of regulating VIP/PHI release.

Anti-nociceptive activity of a few structurally related trimethoxy flavones and possible mechanisms involved

2016 ◽  
Vol 27 (2) ◽  
Author(s):  
Jagan Nadipelly ◽  
Vijaykumar Sayeli ◽  
Parimala Kadhirvelu ◽  
Jaikumar Shanmugasundaram ◽  
Binoy Varghese Cheriyan ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Hot Water ◽  
Dependent Manner ◽  
Tail Immersion ◽  
Dopaminergic Mechanisms ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent ◽  
Definite Role

AbstractThe present study was designed to investigate the anti-nociceptive activity of a few structurally related trimethoxy flavones (7,2′,3′-TMF, 7,2′,4′-TMF, 7,3′,4′-TMF and 7,5,4′-TMF) and the possible mechanisms involved.Anti-nociceptive activity was evaluated in mice by employing acetic acid-induced writhing, formalin-induced nociception and hot water tail immersion methods. The involvement of opioid, GABAergic, tryptaminergic, adrenergic and dopaminergic mechanisms and KTrimethoxy flavones exhibited a significant and dose-dependent inhibition of acetic acid writhing. The paw-licking response time was reduced both in the early and late phases of formalin nociception in a dose-dependent manner by trimethoxy flavones. A significant increase in tail withdrawal latency time was also observed after trimethoxy flavones treatment. These observations revealed the potential anti-nociceptive action of the investigated trimethoxy flavones. Pretreatment with naloxone and bicuculline significantly attenuated the reduction of abdominal constrictions produced by all the tested trimethoxy flavones indicating a definite role of opioid and GABAergic mechanisms in the anti-nociceptive effect of trimethoxy flavones. The anti-nociceptive action elicited by various trimethoxy flavones was differently modulated by glibenclamide, ondansetron, yohimbine and sulpiride.The investigated trimethoxy flavones exhibited promising anti-nociceptive activity in various nociceptive models, and multiple mechanisms are involved in the anti-nociceptive activity of these compounds.

scholarly journals Generation and Analysis of Mice Lacking the Chemokine Fractalkine

2001 ◽  
Vol 21 (9) ◽  
pp. 3159-3165 ◽  
Author(s):  
Donald N. Cook ◽  
Shu-Cheng Chen ◽  
Lee M. Sullivan ◽  
Denise J. Manfra ◽  
Maria T. Wiekowski ◽  
...  
Keyword(s):  
Gene Disruption ◽  
Surface Marker ◽  
Wild Type ◽  
Blood Leukocytes ◽  
Targeted Gene Disruption ◽  
Behavioral Abnormalities ◽  
Inflammatory Stimuli ◽  
Membrane Bound ◽  
Deficient Mice

ABSTRACT Fractalkine (CX3CL1) is the first described chemokine that can exist either as a soluble protein or as a membrane-bound molecule. Both forms of fractalkine can mediate adhesion of cells expressing its receptor, CX3CR1. This activity, together with its expression on endothelial cells, suggests that fractalkine might mediate adhesion of leukocytes to the endothelium during inflammation. Fractalkine is also highly expressed in neurons, and its receptor, CX3CR1, is expressed on glial cells. To determine the biologic role of fractalkine, we used targeted gene disruption to generate fractalkine-deficient mice. These mice did not exhibit overt behavioral abnormalities, and histologic analysis of their brains did not reveal any gross changes compared to wild-type mice. In addition, these mice had normal hematologic profiles except for a decrease in the number of blood leukocytes expressing the cell surface marker F4/80. The cellular composition of their lymph nodes did not differ significantly from that of wild-type mice. Similarly, the responses offractalkine −/− mice to a variety of inflammatory stimuli were indistinguishable from those of wild-type mice.

Possible Pathways Of Arachidonic Acid Liberation As Studied With Purified Phospholipases

1981 ◽  
Author(s):  
H Chap ◽  
B Perret ◽  
G Mauco ◽  
M Plantavid ◽  
F Laffont ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Plasma Membrane ◽  
Phospholipase C ◽  
Ph Dependence ◽  
Plasma Lipoproteins ◽  
Heterogeneous Distribution ◽  
Outer Leaflet ◽  
Membrane Bound

Two kinds of informations about arachidonic acid (AA) metabolism in platelet phospholipids (PL) have been obtained from the use of purified phospholipases: 1) Beside the determination of PL sidedness in the plasma membrane, non-lytic degradation by phospholipase A2 + sphingomyelinase C showed that only 6 % of the total platelet AA is localized in the outer surface of the plasma membrane. This heterogeneous distribution is actually a consequence of PL asymmetry, since sphingomyelin and phosphatidylcholine, which predominate in membrane outer leaflet, contain only traces or relatively lower amounts, respectively, of AA than the internal lipids. It is further shown that incubating platelets with free AA specifically labels the large internal pool of AA, whereas the small external pool is renewed by a direct exchange of phosphatidylcholine with plasma lipoproteins. This offers a doublelabelling method allowing to explore the exact role of each AA pool.2) Platelet aggregation by Clostridium welchii phospholipase C produces the same metabolic changes (accumulation of phosphatidic and lysophosphatidic acids) as those induced by thrombin. These observations have led to describe the existence of a cytosolic phosphatidylinositol-specific phospholipase C and a membrane-bound diglyceride lipase. Both enzymes, coupled to diglyceride− (and monoglyceride−) kinase(s), could achieve AA release and (lyso) phosphatidic acid accumulation. Some properties of these enzymes (subcellular localization, calcium and pH dependence, positional specificity) will be presented.

scholarly journals Hydrogen Sulfide Impairs Meiosis Resumption in Xenopus laevis Oocytes

Cells ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 237
Author(s):  
Armance Gelaude ◽  
Sylvain Slaby ◽  
Katia Cailliau ◽  
Matthieu Marin ◽  
Arlette Lescuyer-Rousseau ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Xenopus Laevis ◽  
Xenopus Laevis Oocytes ◽  
Oocyte Meiosis ◽  
M Phase ◽  
Dependent Inhibition ◽  
Mercaptopyruvate Sulfurtransferase ◽  
Amplification Loop ◽  
Dose Dependent Inhibition

The role of hydrogen sulfide (H2S) is addressed in Xenopus laevis oocytes. Three enzymes involved in H2S metabolism, cystathionine β-synthase, cystathionine γ-lyase, and 3-mercaptopyruvate sulfurtransferase, were detected in prophase I and metaphase II-arrested oocytes and drove an acceleration of oocyte meiosis resumption when inhibited. Moreover, meiosis resumption is associated with a significant decrease in endogenous H2S. On another hand, a dose-dependent inhibition was obtained using the H2S donor, NaHS (1 and 5 mM). NaHS impaired translation. NaHS did not induce the dissociation of the components of the M-phase promoting factor (MPF), cyclin B and Cdk1, nor directly impacted the MPF activity. However, the M-phase entry induced by microinjection of metaphase II MPF-containing cytoplasm was diminished, suggesting upstream components of the MPF auto-amplification loop were sensitive to H2S. Superoxide dismutase and catalase hindered the effects of NaHS, and this sensitivity was partially dependent on the production of reactive oxygen species (ROS). In contrast to other species, no apoptosis was promoted. These results suggest a contribution of H2S signaling in the timing of amphibian oocytes meiosis resumption.

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