scholarly journals Relationship between hormonal, GTP and Ins(1,4,5)P3-stimulated Ca2+ uptake and release in pancreatic acinar cells

1989 ◽  
Vol 263 (2) ◽  
pp. 333-339 ◽  
Author(s):  
S Muallem ◽  
T G Beeker
Keyword(s):  
Protein Kinase C ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Pancreatic Acini ◽  
Intracellular Pool ◽  
Permeabilized Cells ◽  
Kinase C ◽  
Uptake Medium ◽  
Uptake And Release ◽  
Stimulation Of

Electrically permeabilized rat pancreatic acini were used to evaluate the contributions of GTP and Ins(1,4,5) P3 to hormone-stimulated Ca2+ uptake and release from intracellular pools. Treatment of permeabilized acini with Ca2+-mobilizing hormones, GTP or GTP[S] resulted in stimulation of an ATP-dependent, VO4(2-)-sensitive Ca2+ uptake into a non-mitochondrial intracellular pool. GTP and GTP[S] also augmented the hormone-mediated stimulation of Ca2+ uptake. Including oxalate in the uptake medium increased Ca2+ uptake into this pool but did not modify the stimulation of Ca2+ uptake induced by hormones or GTP. Ins(1,4,5)P3 released all the extra Ca2+ accumulated as a result of hormone, GTP or GTP[S] stimulation. Hence, these stimuli activated the Ca2+ pump localized in the membrane of the hormone and Ins(1,4,5)P3-sensitive Ca2+ pool. Including 2,3-diphosphoglyceric acid (PGA) [an inhibitor of Ins(1,4,5)P3 hydrolysis] in the incubation medium blunted the GTP and GTP[S]-stimulated Ca2+ uptake. In the presence of PGA, the hormones inhibited Ca2+ accumulation, and GTP and GTP[S] augmented this effect. Accordingly, PGA stabilized the Ins(1,4,5)P3-evoked Ca2+ release from intracellular pools. Only in the presence of PGA was it possible to demonstrate hormonally-evoked Ca2+ release from permeabilized cells. GTP, and more importantly GTP[S], augmented the hormone-evoked Ca2+ release. Hormones and Ins(1,4,5)P3 in the presence or absence of GTP or GTP[S] released Ca2+ from the same intracellular pool. The extent of Ca2+ release caused by the combination of hormones and GTP or GTP[S] was similar to that evoked by Ins(1,4,5)P3 alone. Taken together, these results suggest that GTP or GTP[S] facilitates stimulation of phospholipase C by hormones. Such stimulation results in stimulation of protein kinase C and increased levels of Ins(1,4,5)P3 and is sufficient to explain the effects of GTP and GTP[S] on Ca2+ uptake and release from pancreatic acinar cells.

Ethanol sensitizes NF-κB activation in pancreatic acinar cells through effects on protein kinase C-ε

2006 ◽  
Vol 291 (3) ◽  
pp. G432-G438 ◽  
Author(s):  
Akihiko Satoh ◽  
Anna S. Gukovskaya ◽  
Joseph R. Reeve ◽  
Tooru Shimosegawa ◽  
Stephen J. Pandol
Keyword(s):  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
High Dose ◽  
Pancreatic Acini ◽  
Kinase C ◽  
Pkc Isoforms ◽  
Ethanol Abuse ◽  
Pkc Ζ ◽  
Sensitizing Effect

Although ethanol abuse is the most common cause of pancreatitis, the mechanism of alcohol's effect on the pancreas is not well understood. Previously, we demonstrated that in vitro ethanol treatment of pancreatic acinar cells augmented the CCK-8-induced activation of NF-κB, a key signaling system involved in the inflammatory response of pancreatitis. In the present study, we determine the role for individual PKC isoforms in the sensitizing effect of ethanol on NF-κB activation. Dispersed rat pancreatic acini were treated with and without ethanol and then stimulated with CCK-8; 100 nM CCK-8 caused both NF-κB and PKC-δ, -ε, and -ζ activation, whereas 0.1 nM CCK-8 did not increase PKC-ε, PKC-ζ, or NF-κB activity. CCK-8 (0.1 nM) did activate PKC-δ. PKC-ε activator alone did not cause NF-κB activation; however, together with 0.1 nM CCK-8, it caused NF-κB activation. Ethanol activated PKC-ε without affecting other PKC isoforms or NF-κB activity. Of note, stimulation of acini with ethanol and 0.1 nM CCK-8 resulted in the activation of PKC-δ, PKC-ε, and NF-κB. The NF-κB activation to 0.1 nM CCK-8 in ethanol-pretreated acini was inhibited by both PKC-δ inhibitor and PKC-ε inhibitor. Taken together, these results demonstrate the different modes of activation of PKC isoforms and NF-κB in acini stimulated with ethanol, high-dose CCK-8, and low-dose CCK-8, and furthermore suggest that activation of both PKC-ε and -δ is required for NF-κB activation. These results suggest that ethanol enhances the CCK-8-induced NF-κB activation at least in part through its effects on PKC-ε.

Transport and interaction of nitrogen oxides and NO2 with CO2-HCO3- transporters in pancreatic acini

1994 ◽  
Vol 267 (2) ◽  
pp. C385-C393 ◽  
Author(s):  
H. Zhao ◽  
X. Xu ◽  
K. Ujiie ◽  
R. A. Star ◽  
S. Muallem
Keyword(s):  
Nitric Oxide ◽  
Nitrogen Oxides ◽  
Acinar Cells ◽  
Cellular Proteins ◽  
Pancreatic Acinar Cells ◽  
Disulfonic Acid ◽  
No Production ◽  
Pancreatic Acini ◽  
Cytosolic Acidification ◽  
Stimulation Of

Recently, we showed that NO2- increases gap junction (GJ) permeability and synchronizes intracellular Ca2+ concentration oscillations in pancreatic acini (Loessburg et al., J. Biol. Chem. 268: 19769-19775, 1993). NO2- is also an end product of nitric oxide (NO) production and metabolism. Because of the effect of NO2- on GJ permeability and the possible importance of NO2- in NO metabolism and cytotoxicity, we used pancreatic acinar cells and intracellular pH (pHi) measurements to study the interaction of nitrogen oxides and NO2- with cellular proteins. Exposing cells to NO2- resulted in a concentration-dependent cytosolic acidification. The acidification did not require the transport of NO2- and was not mediated by diffusion of HNO2. Because the acidification was prevented by CO2-HCO3- and inhibition of carbonic anhydrase, it is possible that other nitrogen oxides present in a solution containing NO2- enter the cells by diffusion and interact with OH- or H2O to stably acidify the cytosol. NO2- itself is shown to be transported by the HCO3- transporters present in the plasma membrane. Thus manipulation of the cellular Cl- gradient and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) were used to show Cl-/NO2- exchange, whereas stimulation of external Na(+)-dependent amiloride-insensitive and DIDS-sensitive pHi increase in acidified cells was used to demonstrate a Na(+)-(NO2-)n cotransport. Hence NO2- can be a convenient substitute for HCO3- when studying HCO3- transport in an open system. The studies also show that cellular levels of nitrogen oxides and NO2- can be modulated by the cellular HCO3(-)-buffering system.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Cholecystokinin Stimulates Formation of Shc-Grb2 Complex in Rat Pancreatic Acinar Cells through a Protein Kinase C-dependent Mechanism

1996 ◽  
Vol 271 (43) ◽  
pp. 27125-27129 ◽  
Author(s):  
Andrzej Dabrowski ◽  
Joyce A. VanderKuur ◽  
Christin Carter-Su ◽  
John A. Williams
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Kinase C ◽  
Dependent Mechanism

Arachidonic acid-induced LH release is ATP-independent and insensitive to N-ethyl maleimide

1992 ◽  
Vol 132 (1) ◽  
pp. 77-82 ◽  
Author(s):  
P. V. Kaye ◽  
P. A. van der Merwe ◽  
R. P. Millar ◽  
J. S. Davidson
Keyword(s):  
Arachidonic Acid ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Pituitary Cells ◽  
Cell Permeabilization ◽  
Intact Cells ◽  
Permeabilized Cells ◽  
Kinase C ◽  
Lh Release ◽  
Stimulation Of

ABSTRACT The mechanism of arachidonic acid (AA)-induced LH release was characterized using sheep pituitary cells in primary culture permeabilized with Staphylococcal α-toxin. In intact cells, exogenous AA evoked release of LH in a manner which was partially dependent on extracellular Ca2+. At similar concentrations, AA also caused cell permeabilization as monitored by efflux of [3H]2-deoxyglucose metabolites. In α-toxin-permeabilized cells where cytosolic Ca2+ was clamped at resting levels, AA retained its ability to cause LH release. Unlike the stimulation of exocytosis produced by Ca2+, phorbol ester or cyclic AMP, AA-evoked release was independent of ATP and was not inhibited by pretreatment with N-ethyl maleimide. These findings indicated that exogenous AA does not cause LH release by Ca2+ influx or mobilization or by activating protein kinase C. The results suggest that LH release induced by exogenous AA is probably due to its detergent-like properties, and does not represent true exocytosis. Journal of Endocrinology (1992) 132, 77–82

scholarly journals Caspase 8-mediated cleavage of plectin precedes F-actin breakdown in acinar cells during pancreatitis

2002 ◽  
Vol 282 (3) ◽  
pp. G450-G460 ◽  
Author(s):  
Michael Beil ◽  
Jürgen Leser ◽  
Manfred P. Lutz ◽  
Anna Gukovskaya ◽  
Thomas Seufferlein ◽  
...  
Keyword(s):  
Cell Injury ◽  
Acinar Cells ◽  
Actin Dynamics ◽  
Pancreatic Acinar Cells ◽  
Caspase 8 ◽  
Pancreatic Acini ◽  
Regulated Secretion ◽  
Edematous Pancreatitis ◽  
System F ◽  
Stimulation Of

Pancreatic acinar cells depend on the integrity of the cytoskeleton for regulated secretion. Stimulation of isolated rat pancreatic acini with the secretagogue CCK serves as a model for human acute edematous pancreatitis. It induces the breakdown of the actin filament system (F-actin) with the consecutive inhibition of secretion and premature activation of digestive enzymes. However, the mechanisms that regulate F-actin breakdown are largely unknown. Plectin is a versatile cytolinker protein regulating F-actin dynamics in fibroblasts. It was recently demonstrated that plectin is a substrate of caspase 8. In pancreatic acinar cells, plectin strongly colocalizes with apical and basolateral F-actin. Supramaximal secretory stimulation of acini with CCK leads to a rapid redistribution and activation of caspase 8, followed by degradation of plectin that in turn precedes the F-actin breakdown. Inhibition of caspase 8 before CCK hyperstimulation prevents plectin cleavage, stabilizes F-actin morphology, and reverses the inhibition of secretion. Thus we propose that the caspase 8-mediated degradation of plectin represents a critical biochemical event during CCK-induced secretory blockade and cell injury.

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