scholarly journals The role of intracellular Ca2+ signaling in the exocrine pancreatic damage during acute pancreatitis

2020 ◽  
Author(s):  
Júlia Fanczal
Keyword(s):  
Oxidative Stress ◽  
Acute Pancreatitis ◽  
Bile Acid ◽  
Bile Acids ◽  
Digestive Enzyme ◽  
Acinar Cells ◽  
Mitochondrial Damage ◽  
Enzyme Activation ◽  
Pancreatic Acinar Cells ◽  
Biliary Pancreatitis

Acute biliary pancreatitis poses a significant clinical challenge as currently no specific pharmaceutical treatment exists. Disturbed intracellular Ca2+ signalling caused by bile acids is a hallmark of the disease, which induces increased reactive oxygen species (ROS) production, mitochondrial damage, intra-acinar digestive enzyme activation and cell death. Because of this mechanism of action, prevention of toxic cellular Ca2+ overload is a promising therapeutic target. Transient receptor potential melastatin 2 (TRPM2) is a non-selective cation channel that has recently emerged as an important contributor to oxidative-stress-induced cellular Ca2+ overload across different diseases. However, the expression and possible functions of TRPM2 in the exocrine pancreas remain unknown. Here we found that TRPM2 is expressed in the plasma membrane of mouse pancreatic acinar, which can be activated by increased oxidative stress induced by H2O2 treatment. TRPM2 activity was found to contribute to bile acid-induced extracellular Ca2+ influx in acinar cells. The generation of intracellular ROS in response to bile acids was remarkably higher in pancreatic acinar cells. This activity promoted acinar cell necrosis in vitro independently from mitochondrial damage or mitochondrial fragmentation. In addition, bile-acid-induced experimental pancreatitis was less severe in TRPM2 knockout mice, whereas the lack of TRPM2 had no protective effect in cerulein-induced acute pancreatitis. Our results suggest that the inhibition of TRPM2 may be a potential treatment option for biliary pancreatitis.

scholarly journals Pharmacological inhibition of PAR2 with the pepducin P2pal-18S protects mice against acute experimental biliary pancreatitis

2013 ◽  
Vol 304 (5) ◽  
pp. G516-G526 ◽  
Author(s):  
E. S. Michael ◽  
A. Kuliopulos ◽  
L. Covic ◽  
M. L. Steer ◽  
G. Perides
Keyword(s):  
Bile Acid ◽  
Acinar Cells ◽  
Experimental Pancreatitis ◽  
In Vivo Studies ◽  
Pancreatic Acinar Cells ◽  
Biliary Pancreatitis ◽  
Zymogen Activation ◽  
Injury Death ◽  
Acid Infusion ◽  
Concentration Changes

Pancreatic acinar cells express proteinase-activated receptor-2 (PAR2) that is activated by trypsin-like serine proteases and has been shown to exert model-specific effects on the severity of experimental pancreatitis, i.e., PAR2−/− mice are protected from experimental acute biliary pancreatitis but develop more severe secretagogue-induced pancreatitis. P2pal-18S is a novel pepducin lipopeptide that targets and inhibits PAR2. In studies monitoring PAR2-stimulated intracellular Ca2+ concentration changes, we show that P2pal-18S is a full PAR2 inhibitor in acinar cells. Our in vivo studies show that P2pal-18S significantly reduces the severity of experimental biliary pancreatitis induced by retrograde intraductal bile acid infusion, which mimics injury induced by endoscopic retrograde cholangiopancreatography (ERCP). This reduction in pancreatitis severity is observed when the pepducin is given before or 2 h after bile acid infusion but not when it is given 5 h after bile acid infusion. Conversely, P2pal-18S increases the severity of secretagogue-induced pancreatitis. In vitro studies indicate that P2pal-18S protects acinar cells against bile acid-induced injury/death, but it does not alter bile acid-induced intracellular zymogen activation. These studies are the first to report the effects of an effective PAR2 pharmacological inhibitor on pancreatic acinar cells and on the severity of experimental pancreatitis. They raise the possibility that a pepducin such as P2pal-18S might prove useful in the clinical management of patients at risk for developing severe biliary pancreatitis such as occurs following ERCP.

scholarly journals Docosahexaenoic Acid Induces Expression of NAD(P)H: Quinone Oxidoreductase and Heme Oxygenase-1 through Activation of Nrf2 in Cerulein-Stimulated Pancreatic Acinar Cells

Antioxidants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1084
Author(s):  
Yu Jin Ahn ◽  
Joo Weon Lim ◽  
Hyeyoung Kim
Keyword(s):  
Oxidative Stress ◽  
Acute Pancreatitis ◽  
Docosahexaenoic Acid ◽  
Heme Oxygenase ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Heme Oxygenase 1 ◽  
Omega 3 ◽  
Quinone Oxidoreductase ◽  
Ar42j Cells

Oxidative stress is a major risk factor for acute pancreatitis. Reactive oxygen species (ROS) mediate expression of inflammatory cytokines such as interleukin-6 (IL-6) which reflects the severity of acute pancreatitis. The nuclear factor erythroid-2-related factor 2 (Nrf2) pathway is activated to induce the expression of antioxidant enzymes such as NAD(P)H: quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1) as a cytoprotective response to oxidative stress. In addition, binding of Kelch-like ECH-associated protein 1 (Keap1) to Nrf2 promotes degradation of Nrf2. Docosahexaenoic acid (DHA)—an omega-3 fatty acid—exerts anti-inflammatory and antioxidant effects. Oxidized omega-3 fatty acids react with Keap1 to induce Nrf2-regulated gene expression. In this study, we investigated whether DHA reduces ROS levels and inhibits IL-6 expression via Nrf2 signaling in pancreatic acinar (AR42J) cells stimulated with cerulein, as an in vitro model of acute pancreatitis. The cells were pretreated with or without DHA for 1 h and treated with cerulein (10−8 M) for 1 (ROS levels, protein levels of NQO1, HO-1, pNrf2, Nrf2, and Keap1), 6 (IL-6 mRNA expression), and 24 h (IL-6 protein level in the medium). Our results showed that DHA upregulates the expression of NQO1 and HO-1 in cerulein-stimulated AR42J cells by promoting phosphorylation and nuclear translocation of Nrf2. DHA increased interaction between Keap1 and Nrf2 in AR42J cells, which may increase Nrf2 activity by inhibiting Keap1-mediated sequestration of Nrf2. In addition, DHA-induced expression of NQO1 and HO-1 is related to reduction of ROS and IL-6 levels in cerulein-stimulated AR42J cells. In conclusion, DHA inhibits ROS-mediated IL-6 expression by upregulating Nrf2-mediated expression of NQO1 and HO-1 in cerulein-stimulated pancreatic acinar cells. DHA may exert positive modulatory effects on acute pancreatitis by inhibiting oxidative stress and inflammatory cytokine production by activating Nrf2 signaling in pancreatic acinar cells.

scholarly journals Pancreatic Acinar Cell Nuclear Factor κB Activation Because of Bile Acid Exposure Is Dependent on Calcineurin

2013 ◽  
Vol 288 (29) ◽  
pp. 21065-21073 ◽  
Author(s):  
Kamaldeen A. Muili ◽  
Shunqian Jin ◽  
Abrahim I. Orabi ◽  
John F. Eisses ◽  
Tanveer A. Javed ◽  
...  
Keyword(s):  
Bile Acid ◽  
Acinar Cell ◽  
Cell Injury ◽  
Nuclear Translocation ◽  
Calcineurin Inhibitors ◽  
Acinar Cells ◽  
Pancreatic Acinar Cell ◽  
Pancreatic Acinar Cells ◽  
Luciferase Reporter ◽  
Biliary Pancreatitis

Biliary pancreatitis is the most common etiology of acute pancreatitis, accounting for 30–60% of cases. A dominant theory for the development of biliary pancreatitis is the reflux of bile into the pancreatic duct and subsequent exposure to pancreatic acinar cells. Bile acids are known to induce aberrant Ca2+ signals in acinar cells as well as nuclear translocation of NF-κB. In this study, we examined the role of the downstream Ca2+ target calcineurin on NF-κB translocation. Freshly isolated mouse acinar cells were infected for 24 h with an adenovirus expressing an NF-κB luciferase reporter. The bile acid taurolithocholic acid-3-sulfate caused NF-κB activation at concentrations (500 μm) that were associated with cell injury. We show that the NF-κB inhibitor Bay 11-7082 (1 μm) blocked translocation and injury. Pretreatment with the Ca2+ chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid, the calcineurin inhibitors FK506 and cyclosporine A, or use of acinar cells from calcineurin Aβ-deficient mice each led to reduced NF-κB activation with taurolithocholic acid-3-sulfate. Importantly, these manipulations did not affect LPS-induced NF-κB activation. A critical upstream regulator of NF-κB activation is protein kinase C, which translocates to the membranes of various organelles in the active state. We demonstrate that pharmacologic and genetic inhibition of calcineurin blocks translocation of the PKC-δ isoform. In summary, bile-induced NF-κB activation and acinar cell injury are mediated by calcineurin, and a mechanism for this important early inflammatory response appears to be upstream at the level of PKC translocation.

Phosphatidylinositol 3-kinase facilitates bile acid-induced Ca2+ responses in pancreatic acinar cells

2007 ◽  
Vol 292 (3) ◽  
pp. G875-G886 ◽  
Author(s):  
L. Fischer ◽  
A. S. Gukovskaya ◽  
J. M. Penninger ◽  
O. A. Mareninova ◽  
H. Friess ◽  
...  
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Phosphatidylinositol 3 Kinase ◽  
Pi3k Inhibitors ◽  
Trypsinogen Activation ◽  
Plasmic Reticulum ◽  
Intracellular Ca ◽  
Phosphatidylinositol 3

Bile acids are known to induce Ca2+ signals in pancreatic acinar cells. We have recently shown that phosphatidylinositol 3-kinase (PI3K) regulates changes in free cytosolic Ca2+ concentration ([Ca2+]i) elicited by CCK by inhibiting sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA). The present study sought to determine whether PI3K regulates bile acid-induced [Ca2+]i responses. In pancreatic acinar cells, pharmacological inhibition of PI3K with LY-294002 or wortmannin inhibited [Ca2+]i responses to taurolithocholic acid 3-sulfate (TLC-S) and taurochenodeoxycholate (TCDC). Furthermore, genetic deletion of the PI3K γ-isoform also decreased [Ca2+]i responses to bile acids. Depletion of CCK-sensitive intracellular Ca2+ pools or application of caffeine inhibited bile acid-induced [Ca2+]i signals, indicating that bile acids release Ca2+ from agonist-sensitive endoplasmic reticulum (ER) stores via an inositol ( 1 , 4 , 5 )-trisphosphate-dependent mechanism. PI3K inhibitors increased the amount of Ca2+ in intracellular stores during the exposure of acinar cells to bile acids, suggesting that PI3K negatively regulates SERCA-dependent Ca2+ reloading into the ER. Bile acids inhibited Ca2+ reloading into ER in permeabilized acinar cells. This effect was augmented by phosphatidylinositol ( 3 , 4 , 5 )-trisphosphate (PIP3), suggesting that both bile acids and PI3K act synergistically to inhibit SERCA. Furthermore, inhibition of PI3K by LY-294002 completely inhibited trypsinogen activation caused by the bile acid TLC-S. Our results indicate that PI3K and its product, PIP3, facilitate bile acid-induced [Ca2+]i responses in pancreatic acinar cells through inhibition of SERCA-dependent Ca2+ reloading into the ER and that bile acid-induced trypsinogen activation is mediated by PI3K. The findings have important implications for the mechanism of acute pancreatitis since [Ca2+]i increases and trypsinogen activation mediate key pathological processes in this disorder.

scholarly journals Protective effects of baicalin on caerulein-induced AR42J pancreatic acinar cells by attenuating oxidative stress through miR-136-5p downregulation

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110261
Author(s):  
Zhu-fen Zhao ◽  
Ye Zhang ◽  
Yang Sun ◽  
Chun-hai Zhang ◽  
Ming-wei Liu
Keyword(s):  
Oxidative Stress ◽  
Acute Pancreatitis ◽  
Relative Survival ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Amylase Level ◽  
Sod1 Gene ◽  
Expression Levels ◽  
Thiazolyl Blue Tetrazolium Bromide ◽  
Gene And Protein Expression

Baicalin, the main active component of Scutellaria baicalensis, has antioxidant and anti-apoptotic effects and is used to treat acute pancreatitis; however, its specific mechanism is unclear. This study aims to determine the protective effect and underlying mechanism of baicalin on AR42J pancreatic acinar cell injury. AR42J acinar cells (caerulein, 10 nmol/L) were induced in vitro to establish a cell model for acute pancreatitis. Cell relative survival was measured by thiazolyl blue tetrazolium bromide, and cell apoptosis and death were examined by flow cytometry. The expression levels of superoxide dismutase1 (SOD1), Bax, survivin, Bcl-2, caspase-3, and caspase-7 proteins were analyzed by Western blot, and those of SOD1 mRNA and miR-136-5p were determined by RT-PCR. The activities of GSH, SOD1, ROS, and MDA were also investigated. Compared with those of the caerulein group, the relative survival rate and activity of AR42J pancreatic acinar cells with different baicalin concentrations were significantly increased ( p < 0.05), and the supernatant amylase level was markedly decreased ( p < 0.05). In addition, the ROS and MDA activities and mir-136-5p expression were significantly decreased, and the GSH activities and SOD1 gene and protein expression levels were markedly increased ( p < 0.05). These results suggest that baicalin reduced the caerulein-induced death of AR42J acinar cells and alleviated the caerulein-induced injury in pancreatic acinar cells by inhibiting oxidative stress. The mechanism may be related to the decreased expression of Mir-136-5p and the increased expression of SOD1 gene and protein.

scholarly journals Absence of the neutrophil serine protease cathepsin G decreases neutrophil granulocyte infiltration but does not change the severity of acute pancreatitis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ali A. Aghdassi ◽  
Daniel S. John ◽  
Matthias Sendler ◽  
Christian Storck ◽  
Cindy van den Brandt ◽  
...  
Keyword(s):  
Acute Pancreatitis ◽  
Serine Protease ◽  
Acinar Cells ◽  
Neutrophil Infiltration ◽  
Cathepsin G ◽  
Pancreatic Acinar Cells ◽  
Neutrophil Granulocyte ◽  
Zymogen Activation ◽  
Trypsinogen Activation ◽  
Extracellular Matrix Components

AbstractAcute pancreatitis is characterized by an early intracellular protease activation and invasion of leukocytes into the pancreas. Cathepsins constitute a large group of lysosomal enzymes, that have been shown to modulate trypsinogen activation and neutrophil infiltration. Cathepsin G (CTSG) is a neutrophil serine protease of the chymotrypsin C family known to degrade extracellular matrix components and to have regulatory functions in inflammatory disorders. The aim of this study was to investigate the role of CTSG in pancreatitis. Isolated acinar cells were exposed to recombinant CTSG and supramaximal cholezystokinin stimulation. In CTSG−/− mice and corresponding controls acute experimental pancreatitis was induced by serial caerulein injections. Severity was assessed by histology, serum enzyme levels and zymogen activation. Neutrophil infiltration was quantified by chloro-acetate ersterase staining and myeloperoxidase measurement. CTSG was expessed in inflammatory cells but not in pancreatic acinar cells. CTSG had no effect on intra-acinar-cell trypsinogen activation. In CTSG−/− mice a transient decrease of neutrophil infiltration into the pancreas and lungs was found during acute pancreatitis while the disease severity remained largely unchanged. CTSG is involved in pancreatic neutrophil infiltration during pancreatitis, albeit to a lesser degree than the related neutrophil (PMN) elastase. Its absence therefore leaves pancreatitis severity essentially unaffected.

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