scholarly journals Limits to the early increase in free cytoplasmic calcium concentration during the mitogenic stimulation of lymphocytes

1983 ◽  
Vol 212 (3) ◽  
pp. 685-690 ◽  
Author(s):  
T R Hesketh ◽  
T Pozzan ◽  
G A Smith ◽  
J C Metcalfe
Keyword(s):  
Cell Cycle ◽  
Calcium Concentration ◽  
Critical Concentration ◽  
Ionophore A23187 ◽  
Cytoplasmic Calcium ◽  
Short Term ◽  
Mitogenic Stimulation ◽  
Short Term Exposure ◽  
Early Increase ◽  
Stimulation Of

Three aspects of the calcium hypothesis we have proposed previously [Metcalfe, Pozzan, Smith & Hesketh (1980) Biochem. Soc. Symp. 45, 1-26] for the control of mitogenic stimulation of lymphocytes are examined in studies on the mitogenic action of the Ca2+ ionophore A23187 and its effect on cap formation. (1) Pig lymphocytes that were mitogenically stimulated by continuous incubation with 3H-labelled A23187 for 48 h contained between 3 and 15 amol of ionophore per cell. Lymphocytes exposed to 3H-labelled A23187 for 2h before washing the cells and resuspending them in ionophore-free medium were only stimulated mitogenically at 48h if the residual ionophore associated with the cells after washing was in the concentration range 3-15 amol per cell. When the cells were washed repeatedly after 2h incubation with ionophore to reduce the cell-associated ionophore below the critical concentration range, no mitogenic stimulation occurred as a result of short-term exposure to any ionophore concentration. Re-addition of ionophore to within the indicated range of cell-associated concentrations restored mitogenic stimulation at 48h. We conclude that large, short-term Ca2+ fluxes into the cells induced by the ionophore cannot generate a mitogenic signal that commits the cells to enter the cell cycle. (2) Further experiments with the ionophore showed that detectable mitogenic stimulation at 48h required a minimum of 3h exposure to optimal ionophore concentrations, and that maximal stimulation required at least 20h exposure. This is consistent with the view that a prolonged increase in the free cytoplasmic calcium concentration is required to stimulate the maximum proportion of the cells into the cell cycle. (3) Mouse splenic lymphocytes treated for short periods with very high ionophore concentrations (30 microM) in the presence of various external Ca2+ concentrations showed significant inhibition of cap formation of surface immunoglobulin receptors in the range 1-10 microM-Ca2+ in normal or depolarizing medium. We conclude that mitogens at optimal concentrations for the stimulation of lymphocytes do not cause any early increase in the free cytoplasmic Ca2+ concentration above 10 microM.

scholarly journals Free cytoplasmic calcium concentration and the mitogenic stimulation of lymphocytes.

1983 ◽  
Vol 258 (8) ◽  
pp. 4876-4882 ◽  
Author(s):  
T R Hesketh ◽  
G A Smith ◽  
J P Moore ◽  
M V Taylor ◽  
J C Metcalfe
Keyword(s):  
Calcium Concentration ◽  
Cytoplasmic Calcium ◽  
Mitogenic Stimulation ◽  
Stimulation Of

Occurrence of molecular abnormalities of cell cycle in L132 cells after in vitro short-term exposure to air pollution PM2.5

2010 ◽  
Vol 188 (3) ◽  
pp. 558-565 ◽  
Author(s):  
Imane Abbas ◽  
Guillaume Garçon ◽  
Françoise Saint-Georges ◽  
Sylvain Billet ◽  
Anthony Verdin ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Air Pollution ◽  
Short Term ◽  
Molecular Abnormalities ◽  
Short Term Exposure

Cold acclimation inhibits CO2-dependent stimulation of photosynthesis in spring wheat and spring rye

Botany ◽  
2012 ◽  
Vol 90 (6) ◽  
pp. 433-444 ◽  
Author(s):  
Keshav Dahal ◽  
Khalil Kane ◽  
Fathey Sarhan ◽  
Bernard Grodzinski ◽  
Norman P.A. Hüner
Keyword(s):  
Triticum Aestivum ◽  
Cold Acclimation ◽  
Temperature Sensitivity ◽  
Spring Wheat ◽  
Secale Cereale ◽  
Triticum Aestivum L ◽  
Short Term ◽  
Short Term Exposure ◽  
Secale Cereale L ◽  
Stimulation Of

We assessed the effects of short-term elevated CO2 on the light-saturated rates of photosynthesis (Asat) of spring (‘SR4A’, ‘Katepwa’) and winter (‘Musketeer’, ‘Norstar’) wheat ( Triticum aestivum L.) and rye ( Secale cereale L.) cultivars grown at ambient CO2 (380 µmol C·mol–1) at either 20/16 °C (nonacclimated, NA) or 5/5 °C (cold acclimated, CA). In spring wheat–rye, cold acclimation decreased CO2-stimulation of Asat by 45%–60% relative to NA controls following a short-term (80 h) shift of plants from ambient to elevated CO2 (700 µmol C·mol–1). In contrast, in winter wheat–rye, cold acclimation enhanced CO2-stimulation of Asat by 15%–35% relative to NA controls upon a shift to elevated CO2. The stimulation observed for CA spring cultivars was about 60% less than that of CA winter cultivars. We conclude that a short-term exposure of spring cultivars to elevated CO2 cannot compensate for the cold acclimation-induced inhibition of Asat. Cold acclimation of spring cultivars appeared to exacerbate Rubisco CO2 substrate limitations present under ambient CO2. Furthermore, CA spring cultivars were unable to adjust their short-term temperature sensitivity of Asat under elevated CO2 compared with the winter cultivars.

In vitro short-term exposure to air pollution PM2.5-0.3 induced cell cycle alterations and genetic instability in a human lung cell coculture model

2016 ◽  
Vol 147 ◽  
pp. 146-158 ◽  
Author(s):  
Imane Abbas ◽  
Anthony Verdin ◽  
Fabienne Escande ◽  
Françoise Saint-Georges ◽  
Fabrice Cazier ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Air Pollution ◽  
Genetic Instability ◽  
Human Lung ◽  
Short Term ◽  
Short Term Exposure ◽  
Cell Cycle Alterations ◽  
Coculture Model

Oxidative stress and cell cycle arrest induced by short-term exposure to dustfall PM2.5 in A549 cells

2017 ◽  
Vol 25 (23) ◽  
pp. 22408-22419 ◽  
Author(s):  
Jie Yang ◽  
Tingting Huo ◽  
Xu Zhang ◽  
Jie Ma ◽  
Yulin Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
A549 Cells ◽  
Short Term ◽  
Cycle Arrest ◽  
Short Term Exposure

scholarly journals Protein kinase C regulates proliferation of mast cells and the expression of the mRNAs of fos and jun proto-oncogenes during activation by IgE-Ag or calcium ionophore A23187

Blood ◽  
1991 ◽  
Vol 78 (9) ◽  
pp. 2354-2364
Author(s):  
D Baranes ◽  
E Razin
Keyword(s):  
Protein Kinase C ◽  
Mast Cells ◽  
Protein Kinase ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Prolonged Treatment ◽  
Ionophore A23187 ◽  
Short Term ◽  
Kinase C ◽  
Short Term Exposure

Short-term stimulation (up to 16 hours) of interleukin-3 (IL-3)- dependent mouse bone marrow-derived mast cells, Abelson transformed mouse liver-derived mast cells, or rat basophilic leukemia cells by either IgE-Ag or calcium ionophore A23187 resulted in inhibition of their proliferation as measured by 3H-thymidine incorporation and MTT (tetrazolium) assays, and in accumulation of the mRNAs of c-fos, c-jun, junB and slightly of junD proto-oncogenes. The involvement of protein kinase C (PKC) in these responses was investigated by using several approaches of enzyme activity regulation. Direct activation of the PKC was achieved by short-term exposure of the cells to the PKC-specific activator phorbol 12-myristate-13-acetate (PMA). Inhibition of PKC activity was obtained by either prolonged treatment of the cells with PMA or by exposure of the cells to the PKC inhibitors H-7 and staurosporine. The results showed the following: (1) Short-term exposure of mast cells to PMA was sufficient to induce inhibition of proliferation. (2) An increase in PKC activity was associated with a decrease in the proliferation of IgE-dinitrophenol (DNP) or calcium ionophore A23187-stimulated cells. (3) A direct correlation was found between the increase in PKC activity and the increase in the level of the mRNAs of the jun proto-oncogenes in cells activated by both stimuli mentioned. (4) While an increase in PKC activity was associated with the upregulation of the level of c-fos mRNA during calcium ionophore A23187 stimulation, it showed the opposite effect on the expression of the mRNA of this proto-oncogene when the cells were triggered by IgE- DNP. Therefore, we concluded that PKC plays various roles in the expression of the mRNA of c-fos in activated mast cells depending on the stimulus involved. In addition, the expression of the mRNA of c-jun and junB proto-onogenes is not coordinately regulated with that of c- fos during immunologic stimulation. This discordancy, which is associated with the increase in PKC activity in mast cells, may play a role in the regulation of the transcription of AP-1-responsive genes, and therefore could be associated with the regulation of proliferation of these cells.

scholarly journals Changes in cytoplasmic calcium determine the secretory response to extracellular cations in human parathyroid cells: a confocal microscopy study using FM1-43 dye

2000 ◽  
Vol 352 (2) ◽  
pp. 353-361 ◽  
Author(s):  
Radu MIHAI ◽  
Teresa LAI ◽  
George J. SCHOFIELD ◽  
John R. FARNDON
Keyword(s):  
Confocal Microscopy ◽  
Plasma Membranes ◽  
Calcium Concentration ◽  
Membrane Surface ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Cytoplasmic Calcium ◽  
Acetoxymethyl Ester ◽  
Prolonged Incubation

Whether activation of the calcium receptor (CaR) modulates secretory events was investigated by real-time fluorescence and confocal microscopy using fura 2 and FM1-43 fluorescent dye. Two paradigms were used: human parathyroid cells, which are stimulated by a step from a high to a low extracellular calcium concentration ([Ca2+]ext), and rMTC6-23 cells, a rat medullary thyroid carcinoma cell line whose secretion is stimulated by an increase in [Ca2+]ext. Parathyroid cells were dispersed from parathyroid adenomas removed from 18 patients with primary hyperparathyroidism. In both cell types, incubation with FM1-43 (2µM) resulted in staining of the plasma membranes, which was rapidly increased following changes in [Ca2+]ext known to stimulate secretion. A high [Ca2+]ext and lanthanum (La3+) decreased the membrane-associated FM1-43 fluorescence. Prolonged incubation (5–30min) in the presence of FM1-43 resulted in accumulation of the dye in the cytoplasm, its granular distribution suggesting targeting of the secretory compartment. These data suggest that FM1-43 fluorescence is determined by: (i) changes in cell membrane surface area associated with secretion-associated events, (ii) displacement/quenching by extracellular cations and (iii) endocytosis of the dye. In parathyroid cells, a rise in FM1-43 fluorescence occurred during incubation in a high (inhibitory) [Ca2+]ext if the cytoplasmic calcium concentration ([Ca2+]i) was decreased by the calcium chelator BAPTA/AM [bis-(o-aminophenoxy)ethane-N,N,Nƀ,Nƀ-tetra-acetic acid tetrakis(acetoxymethyl ester)] (10–50µM). Alternatively, the expected rise in FM1-43 fluorescence did not occur during incubation in a low (stimulatory) [Ca2+]ext if [Ca2+]i was increased by addition of the calcium ionophore A23187 (10–25µM). These data suggest that [Ca2+]i, rather than the absolute value of [Ca2+]ext, is the main modulator of secretion from parathyroid cells.

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