scholarly journals Amylase release from streptolysin O-permeabilized pancreatic acinar cells. Effects of Ca2+, guanosine 5′-[γ-thio]triphosphate, cyclic AMP, tetanus toxin and botulinum A toxin

1992 ◽  
Vol 283 (3) ◽  
pp. 899-904 ◽  
Author(s):  
B Stecher ◽  
G Ahnert-Hilger ◽  
U Weller ◽  
T P Kemmer ◽  
M Gratzl
Keyword(s):  
Cyclic Amp ◽  
Tetanus Toxin ◽  
Proteolytic Enzymes ◽  
Acinar Cells ◽  
Pancreatic Acinar Cell ◽  
Pancreatic Acinar Cells ◽  
Amylase Release ◽  
Botulinum A Toxin ◽  
Streptolysin O ◽  
Clostridial Neurotoxins

The molecular requirements for amylase release and the intracellular effects of botulinum A toxin and tetanus toxin on amylase release were investigated using rat pancreatic acinar cells permeabilized with streptolysin O. Micromolar concentrations of free Ca2+ evoked amylase release from these cells. Maximal release was observed in the presence of 30 microM free Ca2+. Ca(2+)-stimulated, but not basal, amylase release was enhanced by guanosine 5′-[gamma-thio]triphosphate (GTP[S]) (3-4 fold) or cyclic AMP (1.5-2 fold). Neither the two-chain forms of botulinum A toxin and tetanus toxin, under reducing conditions, nor the light chains of tetanus toxin, inhibited amylase release triggered by Ca2+, or combinations of Ca2+ + GTP[S] or Ca2+ + cAMP. The lack of inhibition was not due to inactivation of botulinum A toxin or tetanus toxin by pancreatic acinar cell proteolytic enzymes, as toxins previously incubated with permeabilized pancreatic acinar cells inhibited Ca(2+)-stimulated [3H]noradrenaline release from streptolysin O-permeabilized adrenal chromaffin cells. These data imply that clostridial neurotoxins inhibit a Ca(2+)-dependent mechanism which promotes exocytosis in neural and endocrine cells, but not in exocrine cells.

Forskolin potentiates calcium-dependent amylase secretion from rat pancreatic acinar cells

1983 ◽  
Vol 61 (10) ◽  
pp. 1168-1176 ◽  
Author(s):  
Seymour Heisler
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Acinar Cells ◽  
Secretory Response ◽  
Pancreatic Acinar Cells ◽  
Secretory Process ◽  
Amylase Secretion ◽  
Primary Role ◽  
Amylase Release ◽  
Calcium Dependent

The cellular and molecular effects of forskolin, a direct, nonhormonal activator of adenylate cyclase, were assessed on the enzyme secretory process in dispersed rat pancreatic acinar cells. Forskolin stimulated adenylate cyclase activity in the absence of guanyl nucleotide. It promoted a rapid and marked increase in cellular accumulation of cyclic AMP alone or in combination with vasoactive intestinal peptide (VIP) but was itself a weak pancreatic agonist and did not increase the secretory response to VIP or other cyclic AMP dependent agonists. Somatostatin was a partial antagonist of forskolin stimulated cyclic AMP synthesis and forskolin plus cholecystokinin-octapeptide (CCK-OP) induced amylase release. Forskolin potentiated amylase secretion in response to calcium-dependent agonists such as CCK-OP, carbachol and A-23187, but did not affect the ability of CCK-OP and (or) carbachol to mobilize 45Ca from isotope preloaded cells; forskolin alone did not stimulate 45Ca release. In calcium-poor media, the secretory response to forskolin and CCK-OP was reduced in a both absolute and relative manner. The data suggests that calcium plays the primary role as intracellular mediator of enzyme secretion and that the role of cyclic AMP may be to modulate the efficiency of calcium utilization.

Effect of oxidative stress on cellular functions and cytosolic free calcium of rat pancreatic acinar cells

1997 ◽  
Vol 272 (6) ◽  
pp. G1489-G1498 ◽  
Author(s):  
H. Klonowski-Stumpe ◽  
R. Schreiber ◽  
M. Grolik ◽  
H. U. Schulz ◽  
D. Haussinger ◽  
...  
Keyword(s):  
Cell Injury ◽  
Cell Damage ◽  
Acinar Cells ◽  
Pancreatic Acinar Cell ◽  
Pancreatic Acinar Cells ◽  
Free Calcium ◽  
Cellular Functions ◽  
Cytosolic Free Calcium ◽  
Catalyzed Oxidation ◽  
Sustained Increase

The present study evaluates the effect of free radicals generated by xanthine oxidase-catalyzed oxidation of hypoxanthine on cellular function of isolated rat pancreatic acinar cells. The results show that a rapid and sustained increase in intracellular Ca2+ concentration ([Ca2+]i) preceded all other morphological and functional alterations investigated. Radical-induced [Ca2+]i increase was largely inhibited by 3,4,5-trimethoxybenzoic acid 8-(diethylamino)octyl ester, which prevents Ca2+ release from intracellular stores, but not by Ca2(+)-depleted medium. Radicals released Ca2+ from thapsigargin-insensitive, ryanodine-sensitive intracellular stores, whereas the secretagogue caerulein at physiological concentrations mainly released Ca2+ from thapsigargin-sensitive stores. In contrast to effects of the secretagogue, radical-induced Ca2+ changes did not cause luminal protein secretion but cell death. In single-cell measurements, both secretagogue and radicals induced oscillations of [Ca2+]i. Radical-induced oscillations had a lower frequency but similar amplitude when compared with caerulein-induced oscillations. 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid and ryanodine, which prevented the radical-induced Ca2+ increase without altering the generation of radicals, markedly reduced the radical-induced cell damage. These results suggest that the Ca2+ increase mediates the radical-induced cell injury. The studies also indicate that not only the extent and duration but also the origin of [Ca2+]i release as well as the frequency of Ca2+ oscillations may determine whether a pancreatic acinar cell will secrete or die.

Oxidizing effects of vanadate on calcium mobilization and amylase release in rat pancreatic acinar cells

1999 ◽  
Vol 58 (1) ◽  
pp. 77-84 ◽  
Author(s):  
José A Pariente ◽  
Ana I Lajas ◽  
Marı́a J Pozo ◽  
Pedro J Camello ◽  
Ginés M Salido
Keyword(s):  
Acinar Cells ◽  
Calcium Mobilization ◽  
Pancreatic Acinar Cells ◽  
Amylase Release ◽  
Oxidizing Effects

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.

Regulation of CCK-induced amylase release by PKC-δ in rat pancreatic acinar cells

2004 ◽  
Vol 287 (4) ◽  
pp. G764-G771 ◽  
Author(s):  
Chenwei Li ◽  
Xuequn Chen ◽  
John A. Williams
Keyword(s):  
Acinar Cells ◽  
Adenoviral Vectors ◽  
Dominant Negative ◽  
Pancreatic Acinar Cells ◽  
Amylase Secretion ◽  
Wild Type ◽  
Amylase Release ◽  
Pkc Isoforms ◽  
Chemical Inhibitors ◽  
Dominant Negative Variant

PKC is known to be activated by pancreatic secretagogues such as CCK and carbachol and to participate along with calcium in amylase release. Four PKC isoforms, α, δ, ε, and ζ, have been identified in acinar cells, but which isoforms participate in amylase release are unknown. To identify the responsible isoforms, we used translocation assays, chemical inhibitors, and overexpression of individual isoforms and their dominant-negative variants by means of adenoviral vectors. CCK stimulation caused translocation of PKC-α, -δ, and -ε, but not -ζ from soluble to membrane fraction. CCK-induced amylase release was inhibited ∼30% by GF109203X, a broad spectrum PKC inhibitor, and by rottlerin, a PKC-δ inhibitor, but not by Gö6976, a PKC-α inhibitor, at concentrations from 1 to 5 μM. Neither overexpression of wild-type or dominant-negative PKC-α affected CCK-induced amylase release. Overexpression of PKC-δ and -ε enhanced amylase release, whereas only dominant-negative PKC-δ inhibited amylase release by 25%. PKC-δ overexpression increased amylase release at all concentrations of CCK, but dominant-negative PKC-δ only inhibited the maximal concentration; both similarly affected carbachol and JMV-180-induced amylase release. Overexpression of both PKC-δ and its dominant-negative variant affected the late but not the early phase of amylase release. GF109203X totally blocked the enhancement of amylase release by PKC-δ but had no further effect in the presence of dominant-negative PKC-δ. These results indicate that PKC-δ is the PKC isoform involved with amylase secretion.

scholarly journals Mechanism and regulation of folate uptake by pancreatic acinar cells: effect of chronic alcohol consumption

2010 ◽  
Vol 298 (6) ◽  
pp. G985-G993 ◽  
Author(s):  
Hamid M. Said ◽  
Lisa Mee ◽  
V. Thillai Sekar ◽  
Balasubramaniem Ashokkumar ◽  
Stephen J. Pandol
Keyword(s):  
Acinar Cells ◽  
Pancreatic Acinar Cell ◽  
Pancreatic Acinar Cells ◽  
Exocrine Function ◽  
Acid Uptake ◽  
Human Pancreas ◽  
Chronic Alcohol ◽  
Transport Inhibitors ◽  
Pancreatic Exocrine ◽  
One Carbon Metabolism

Folate plays an essential role in one-carbon metabolism, and a relationship exists between methyl group metabolism and pancreatic exocrine function. Little, however, is known about the mechanism(s) and regulation of folate uptake by pancreatic acinar cells and the effect of chronic alcohol use on the process. We addressed these issues using the rat-derived pancreatic acinar cell line AR42J and freshly isolated primary rat pancreatic acinar cells as models. We found [3H]folic acid uptake to be 1) temperature and pH dependent with a higher uptake at acidic than at neutral/alkaline pH; 2) saturable as a function of substrate concentration at both buffer pH 7.4 and 6.0; 3) inhibited by folate structural analogs and by anion transport inhibitors at both buffer pH 7.4 and 6.0; 4) trans-stimulated by unlabeled folate; 5) adaptively regulated by the prevailing extracellular folate level, and 6) inhibited by modulators of the cAMP/PKA-mediated pathway. Both the reduced folate carrier (RFC) and the proton-coupled folate transporter (PCFT) were found to be expressed in AR42J and in primary pancreatic acinar cells, as well as in native human pancreas with expression of RFC being higher than PCFT. Chronic alcohol feeding of rats (4 wk; 36% of calories from ethanol) led to a significant decrease in folate uptake by freshly isolated primary pancreatic acinar cells compared with cells from pair-fed controls; this effect was associated with a parallel decrease in the level of expression of RFC and PCFT. These studies reveal that folate uptake by pancreatic acinar cells is via a regulated carrier-mediated process which may involve RFC and PCFT. In addition, chronic alcohol feeding leads to a marked inhibition in folate uptake by pancreatic acinar cells, an effect that is associated with reduction in level of expression of RFC and PCFT.

MiR-155 aggravates impaired autophagy of pancreatic acinar cells through targeting Rictor

2020 ◽  
Vol 52 (2) ◽  
pp. 192-199 ◽  
Author(s):  
Xueming Zhang ◽  
Jiangtao Chu ◽  
Haijun Sun ◽  
Dali Zhao ◽  
Biao Ma ◽  
...  
Keyword(s):  
Acinar Cells ◽  
Immunofluorescence Assay ◽  
Pancreatic Acinar Cell ◽  
Pancreatic Acinar Cells ◽  
Luciferase Reporter ◽  
Cellular Model ◽  
Protein Levels ◽  
Ar42j Cells ◽  
Direct Target ◽  
Dual Luciferase Reporter Assay

Abstract The aim of this study was to investigate the role and mechanism of miR-155 in regulating autophagy in a caerulein-induced acute pancreatitis (AP) cellular model. GFP-LC3 immunofluorescence assay was performed to detect autophagy vesicle formation in pancreatic acinar cell line AR42J. AR42J cells were transfected with miR-155 mimic, inhibitor, and corresponding controls to explore the effect of miR-155 on autophagy. The protein levels of LC3-I, LC3-II, Beclin-1, and p62 were analyzed by western blot analysis. Dual-luciferase reporter assay was performed to verify the interaction between miR-155 and Rictor (RPTOR independent companion of MTOR complex 2). The results showed that caerulein treatment induced impaired autophagy as evidenced by an increase in the accumulation of p62 together with LC3-II in AR42J cells, accompanied by miR-155 upregulation. Furthermore, miR-155 overexpression aggravated, whereas miR-155 silencing reduced the caerulein-induced impairment of autophagy. Mechanistically, Rictor was confirmed to be a direct target of miR-155, which could rescue the miR-155 overexpression-mediated aggravation of impaired autophagy. Collectively, these findings indicate that miR-155 aggravates impaired autophagy in caerulein-treated pancreatic acinar cells by targeting Rictor.

Adenovirus-mediated gene transfer of RasN17 inhibits specific CCK actions on pancreatic acinar cells

1999 ◽  
Vol 276 (2) ◽  
pp. G499-G506 ◽  
Author(s):  
Barbara Nicke ◽  
Min-Jen Tseng ◽  
Marycarol Fenrich ◽  
Craig D. Logsdon
Keyword(s):  
Dna Synthesis ◽  
Intracellular Signaling ◽  
Acinar Cells ◽  
Dominant Negative ◽  
Pancreatic Acinar Cells ◽  
Dominant Negative Mutant ◽  
Ras Gene ◽  
Amylase Release ◽  
Jun Kinase

CCK stimulates pleiotrophic responses in pancreatic acinar cells; however, the intracellular signaling pathways involved are not well understood. To evaluate the role of the ras gene product in CCK actions, a strategy involving in vitro adenoviral-mediated gene delivery of a dominant-negative mutant Ras (RasN17) was utilized. Isolated acini were infected with various titers of either a control adenovirus or an adenoviral construct expressing RasN17 for 24 h before being treated with CCK. Titer-dependent expression of RasN17 in the acini was confirmed by Western blotting. Infection with control adenovirus [106–109plaque-forming units/mg acinar protein (multiplicity of infection of ∼1–1,000)] had no effect on CCK stimulation of acinar cell amylase release, extracellular-regulated kinase (ERK) or c-Jun kinase (JNK) kinases, or DNA synthesis. In contrast, infection with adenovirus bearing ras N17 increased basal amylase release, inhibited CCK-mediated JNK activation, had no effect on CCK activation of ERK, and inhibited DNA synthesis. These data demonstrate important roles for Ras in specific actions of CCK on pancreatic acinar function.

Crambene induces pancreatic acinar cell apoptosis via the activation of mitochondrial pathway

2006 ◽  
Vol 291 (1) ◽  
pp. G95-G101 ◽  
Author(s):  
Yang Cao ◽  
Sharmila Adhikari ◽  
Abel Damien Ang ◽  
Marie Véronique Clément ◽  
Matthew Wallig ◽  
...  
Keyword(s):  
Acinar Cell ◽  
Cell Apoptosis ◽  
Caspase 3 ◽  
Fas Ligand ◽  
Annexin V ◽  
Acinar Cells ◽  
Mitochondrial Pathway ◽  
Pancreatic Acinar Cell ◽  
Pancreatic Acinar Cells ◽  
Pancreatic Acini

We investigated the apoptotic pathway activated by crambene (1-cyano-2-hydroxy-3-butene), a plant nitrile, on pancreatic acinar cells. As evidenced by annexin V-FITC staining, crambene treatment for 3 h induced the apoptosis but not necrosis of pancreatic acini. Caspase-3, -8, and -9 activities in acini treated with crambene were significantly higher than in untreated acini. Treatment with caspase-3, -8, and -9 inhibitors inhibited annexin V staining, as well as caspase-3 activity, pointing to an important role of these caspases in crambene-induced acinar cell apoptosis. The mitochondrial membrane potential was collapsed, and cytochrome c was released from the mitochondria in crambene-treated acini. Neither TNF-α nor Fas ligand levels were changed in pancreatic acinar cells after crambene treatment. These results provide evidence for the induction of pancreatic acinar cell apoptosis in vitro by crambene and suggest the involvement of mitochondrial pathway in pancreatic acinar cell apoptosis.

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