Roles of Cholecystokinin Receptor Phosphorylation in Agonist-Stimulated Desensitization of Pancreatic Acinar Cells and Receptor-Bearing Chinese Hamster Ovary Cholecystokinin Receptor Cells

1997 ◽  
Vol 51 (2) ◽  
pp. 185-192 ◽  
Author(s):  
Rammohan V. Rao ◽  
Belinda F. Roettger ◽  
Elizabeth M. Hadac ◽  
Laurence J. Miller
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Receptor Phosphorylation ◽  
Cholecystokinin Receptor ◽  
Receptor Cells

Reduced cholecystokinin receptor phosphorylation and restored signalling in protein kinase C down-regulated rat pancreatic acinar cells

1998 ◽  
Vol 435 (3) ◽  
pp. 422-428 ◽  
Author(s):  
Rolf L. L. Smeets ◽  
Rammohan V. Rao ◽  
Sjenet E. van Emst-de Vries ◽  
Jan Joep H. H. M. De Pont ◽  
Laurence J. Miller ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Receptor Phosphorylation ◽  
Cholecystokinin Receptor ◽  
Kinase C

scholarly journals Control of cholecystokinin receptor dephosphorylation in pancreatic acinar cells

1993 ◽  
Vol 268 (16) ◽  
pp. 12136-12142
Author(s):  
M.P. Lutz ◽  
D.I. Pinon ◽  
L.K. Gates ◽  
S. Shenolikar ◽  
L.J. Miller
Keyword(s):  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Cholecystokinin Receptor

scholarly journals Inhibitory effect of high leucine concentration on α-amylase secretion by pancreatic acinar cells: possible key factor of proteasome

2018 ◽  
Vol 38 (6) ◽  
Author(s):  
Long Guo ◽  
Baolong Liu ◽  
Chen Zheng ◽  
Hanxun Bai ◽  
Hao Ren ◽  
...  
Keyword(s):  
Amylase Activity ◽  
Acinar Cells ◽  
Inhibitory Effect ◽  
Proteasome Activity ◽  
Pancreatic Acinar Cells ◽  
Amylase Secretion ◽  
High Concentration ◽  
Amylase Release ◽  
Cholecystokinin Receptor ◽  
Key Factor

The present study aimed to investigate whether leucine affects the pancreatic exocrine by controlling the antisecretory factor (AF) and cholecystokinin receptor (CCKR) expression as well as the proteasome activity in pancreatic acinar cells of dairy calves. The pancreatic acinar cells were isolated from newborn Holstein bull calves and cultured using the Dulbecco’s modified Eagle’s medium/nutrient mixture F12 Ham’s liquid (DMEM/F12). There were six treatments of leucine dosage including 0 (control), 0.23, 0.45, 1.35, 4.05, and 12.15 mM, respectively. After culture for 3 h, the samples were collected for subsequent analysis. As the leucine concentration increased from 0 to 1.35 mM, the α-amylase activity in media decreased significantly (P<0.05), while further increase in leucine concentration did not show any decrease in α-amylase activity. Addition of leucine inhibited (P<0.05) the expression of AF and CCKR, and decreased the activity of proteasome (P<0.05) by 76%, 63%, 24%, 7%, and 9%, respectively. Correlation analysis results showed α-amylase secretion was negatively correlated with leucine concentration (P<0.01), and positively correlated with proteasome activity (P<0.01) and the expression of CCK1R (P<0.01) and AF (P<0.05). The biggest regression coefficient was showed between α-amylase activity and proteasome (0.7699, P<0.001). After inhibition of proteasome by MG-132, low dosage leucine decreased (P<0.05) the activity of proteasome and α-amylase, as well as the expression of CCK1R. In conclusion, we demonstrated that the high-concentration leucine induced decrease in α-amylase release was mainly by decreasing proteasome activity.

CCK independently activates intracellular trypsinogen and NF-κB in rat pancreatic acinar cells

2001 ◽  
Vol 280 (3) ◽  
pp. C465-C472 ◽  
Author(s):  
Bing Han ◽  
Baoan Ji ◽  
Craig D. Logsdon
Keyword(s):  
Chinese Hamster ◽  
Acinar Cells ◽  
Nuclear Factor Κb ◽  
Pancreatic Acinar Cells ◽  
Pyrrolidine Dithiocarbamate ◽  
Trypsinogen Activation ◽  
Independent Events ◽  
Dna Binding Assay ◽  
The Relationship ◽  
Stimulation Of

In the cholecystokinin (CCK) hyperstimulation model of acute pancreatitis, two early intracellular events, activation of trypsinogen and activation of nuclear factor-κB (NF-κB), are thought to be important in the development of the disease. In this study, the relationship between these two events was investigated. NF-κB activity was monitored by using a DNA binding assay and mob-1 chemokine gene expression. Intracellular trypsin activity was measured by using a fluorogenic substrate. Protease inhibitors including FUT-175, Pefabloc, and E-64d prevented CCK stimulation of intracellular trypsinogen and NF-κB activation. Likewise, the NF-κB inhibitors pyrrolidine dithiocarbamate and N-acetyl-l-cysteine inhibited CCK stimulation of NF-κB and intracellular trypsinogen activation. These results suggested a possible codependency of these two events. However, CCK stimulated NF-κB activation in Chinese hamster ovary-CCKAcells, which do not express trypsinogen, indicating that trypsin is not necessary for CCK activation of NF-κB. Furthermore, adenovirus-mediated expression in acinar cells of active p65 subunits to stimulate NF-κB, or of inhibitory κB-α molecules to inhibit NF-κB, did not affect either basal or CCK-mediated trypsinogen activation. Thus trypsinogen and NF-κB activation are independent events stimulated by CCK.

scholarly journals Cholecystokinin octapeptide inhibits Ca2+-dependent amylase secretion from permeabilized pancreatic acini by blocking the MgATP-dependent priming of exocytosis

1998 ◽  
Vol 330 (1) ◽  
pp. 329-334 ◽  
Author(s):  
J. Philip PADFIELD ◽  
Ninder PANESAR
Keyword(s):  
Acinar Cells ◽  
Secretory Response ◽  
Pancreatic Acinar Cells ◽  
Amylase Secretion ◽  
Rapid Phase ◽  
Pancreatic Acini ◽  
Cholecystokinin Octapeptide ◽  
Cholecystokinin Receptor ◽  
Specific Antagonist

At present little is known about how the low-affinity cholecystokinin receptor inhibits secretagogue-stimulated amylase secretion from pancreatic acinar cells. To examine this question we have determined how cholecystokinin octapeptide (CCK8) influences Ca2+-dependent amylase secretion from α-toxin-permeabilized pancreatic acini. CCK8 significantly inhibited Ca2+-stimulated amylase secretion. The inhibitory actions of CCK8 were completely blocked by the addition of JMV-180, a specific antagonist for the low-affinity CCK8 receptor. Previous studies have shown that Ca2+-dependent amylase secretion from α-toxin-permeabilized acini has two distinct phases [Padfield and Panesar (1997) Am. J. Physiol. 36, G655-660]. There is an initial rapid phase of secretion which represents release from exocytotic sites primed by MgATP prior to permeabilization. This is followed by a slower sustained phase of secretion which, in part, reflects the MgATP-dependent repriming of the exocytotic machinery. CCK8 did not influence the initial rapid phase of the Ca2+-dependent secretory response, but inhibited the second slower sustained phase. Moreover, CCK8 was shown to inhibit the MgATP-dependent priming of exocytosis in the acini. These results indicate that the low-affinity CCK receptor blocks stimulated amylase secretion by inhibiting the MgATP-dependent repriming of exocytosis.

scholarly journals Regulation of lateral mobility and cellular trafficking of the CCK receptor by a partial agonist

1999 ◽  
Vol 276 (3) ◽  
pp. C539-C547 ◽  
Author(s):  
Belinda F. Roettger ◽  
Delia I. Pinon ◽  
Thomas P. Burghardt ◽  
Laurence J. Miller
Keyword(s):  
Acinar Cell ◽  
Partial Agonist ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Cellular Trafficking ◽  
Lateral Mobility ◽  
Cck Receptors ◽  
The Impact

Partial agonists are effective tools for advancing development of highly selective drugs and providing insights into molecular regulation of cellular functions. Here, we explore the impact of a partial agonist on key aspects of cholecystokinin (CCK) receptor regulation, its lateral mobility and cellular trafficking, in native pancreatic acinar cells and Chinese hamster ovary cells expressing CCK receptor (CHO-CCKR). We developed and characterized a novel fluorescent partial agonist, rhodamine-Gly-[(Nle28,31)CCK-26–32]-phenethyl ester, that binds specifically and with high affinity to CCK receptors. Such analogs are fully efficacious pancreatic acinar cell secretagogues without supramaximal inhibition that mobilize intracellular calcium with little or no increase in phospholipase C (PLC) activity. Despite minimal phosphorylation of CCK receptors in response to this partial agonist, receptor trafficking was the same as that observed with full agonist (CCK). This included normal internalization via clathrin-dependent endocytosis in CHO-CCKR cells and insulation on the surface of pancreatic acinar cells. Also, as with CCK-occupied receptor, fluorescence recovery after photobleaching of partial agonist-occupied receptor on the acinar cell surface demonstrated a marked temperature-dependent slowing of its rate of diffusion. This was similarly associated with resistance to acid-induced dissociation of ligand. Thus some key molecular regulatory mechanisms for CCK receptor internalization and insulation may be initiated by cellular signaling cascades that are not dependent on PLC activation or receptor phosphorylation.

Cellular handling of unoccupied and agonist-stimulated cholecystokinin receptor determined by immunolocalization

1997 ◽  
Vol 272 (3) ◽  
pp. G488-G497 ◽  
Author(s):  
C. Fischer de Toledo ◽  
B. F. Roettger ◽  
C. Morys-Wortmann ◽  
W. E. Schmidt ◽  
L. J. Miller
Keyword(s):  
Chinese Hamster ◽  
Receptor Internalization ◽  
Ovary Cell ◽  
Pancreatic Acinar Cells ◽  
Direct Result ◽  
Cck Receptors ◽  
Cholecystokinin Receptor ◽  
Surface Receptors ◽  
Ovary Cell Line ◽  
Intracellular Domains

Cellular handling of receptor molecules is an important mechanism for the regulation of appropriately sensitive hormone-stimulated signaling. Until now, our understanding of the cellular handling of the cholecystokinin (CCK) receptor has been largely limited to following a tagged ligand through the cell. In the present work, we report the application of unique CCK receptor antisera directed toward intracellular domains, which permitted the immunolocalization of this molecule independently of its occupation with ligand. The CCK receptor antisera were also useful in Western blotting and immunoprecipitation of this receptor. Unstimulated CCK receptors remained on the surface of both recombinant stable rat CCK-A receptor-bearing Chinese hamster ovary cell line (CHO-CCKR) cells and native rat pancreatic acinar cells and did not constitutively internalize. Agonist stimulation of the CHO-CCKR cells resulted in the prompt internalization of a subset of surface receptors, representing those that were occupied with ligand. Unoccupied receptors remained on the surface, uninfluenced by the stimulated signaling pathways. Consistent with this, CCK receptor phosphorylation induced by 12-O-tetradecanoylphorbol-13-acetate treatment did not stimulate receptor internalization. After internalization, we observed substantial receptor recycling to the plasma membrane. These insights provide the first evidence that CCK receptor internalization occurs as a direct result of an induced conformational change and presumed bimolecular interaction, rather than as an effect of a signaling event.

Effect of ethanol on cholecystokinin-stimulated zymogen conversion in pancreatic acinar cells

1996 ◽  
Vol 270 (1) ◽  
pp. G171-G175 ◽  
Author(s):  
M. Katz ◽  
R. Carangelo ◽  
L. J. Miller ◽  
F. Gorelick
Keyword(s):  
Acinar Cell ◽  
Low Dose ◽  
Acinar Cells ◽  
Pancreatic Acinar Cell ◽  
Pancreatic Acinar Cells ◽  
Ethanol Treatment ◽  
Cholecystokinin Receptor ◽  
Cholecystokinin Receptors ◽  
High Doses ◽  
Activation Cascade

Exocrine pancreatic zymogens are proteolytically processed to active forms after they are secreted into the small intestine. However, intracellular conversion of zymogens to active forms can be stimulated by treating pancreatic acinar cells with high doses of cholecystokinin (0.1 microM) or carbamylcholine (0.1 mM). The high doses of cholecystokinin are unlikely to be achieved physiologically. The ability of ethanol to sensitize the acinar cell to zymogen conversion Induced by cholecystokinin or carbamylcholine was examined. Ethanol (10-200 mM) had no effect alone or when combined with carbamylcholine. However, ethanol (25 mM) added with low-dose cholecystokinin (0.1 nM) generated zymogen conversion that was 1) sixfold higher than cholecystokinin alone and 2) equivalent to that generated by highdose cholecystokinin (10 microM). The ability of ethanol to enhance cholecystokinin-induced zymogen conversion was dependent on the dose of ethanol and the duration of ethanol treatment. The cholecystokinin receptor antagonist, L-364,718, blocked the conversion stimulated by the addition of ethanol with cholecystokinin. This effect of ethanol did not change the affinity or number of cholecystokinin receptors, suggesting an effect more distal in the stimulus-activation cascade. These findings demonstrate that ethanol selectively sensitizes the pancreatic acinar cell to cholecystokinin-stimulated zymogen proteolysis.

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