Differential Cytotoxicity, ER/Oxidative Stress, Dysregulated AMPKα Signaling and Mitochondrial Stress by Ethanol and its Metabolites in Human Pancreatic Acinar Cells

Author(s):  
Mukund P. Srinivasan ◽  
Kamlesh K Bhopale ◽  
Anna A Caracheo ◽  
Lata Kaphalia ◽  
Gopalakrishnan Loganathan ◽  
...  
Pancreas ◽  
1993 ◽  
Vol 8 (4) ◽  
pp. 465-470 ◽  
Author(s):  
Hidekazu Suzuki ◽  
Makoto Suematsu ◽  
Soichiro Miura ◽  
Hiroshi Asako ◽  
Iwao Kurose ◽  
...  

Antioxidants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1084
Author(s):  
Yu Jin Ahn ◽  
Joo Weon Lim ◽  
Hyeyoung Kim

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.


2009 ◽  
Vol 1171 (1) ◽  
pp. 545-548 ◽  
Author(s):  
Joo Weon Lim ◽  
Ji Yeon Song ◽  
Jeong Yeon Seo ◽  
Hyeyoung Kim ◽  
Kyung Hwan Kim

2008 ◽  
Vol 295 (5) ◽  
pp. C1247-C1260 ◽  
Author(s):  
Erin M. Baggaley ◽  
Austin C. Elliott ◽  
Jason I. E. Bruce

Impairment of the normal spatiotemporal pattern of intracellular Ca2+ ([Ca2+]i) signaling, and in particular, the transition to an irreversible “Ca2+ overload” response, has been implicated in various pathophysiological states. In some diseases, including pancreatitis, oxidative stress has been suggested to mediate this Ca2+ overload and the associated cell injury. We have previously demonstrated that oxidative stress with hydrogen peroxide (H2O2) evokes a Ca2+ overload response and inhibition of plasma membrane Ca2+-ATPase (PMCA) in rat pancreatic acinar cells (Bruce JI and Elliott AC. Am J Physiol Cell Physiol 293: C938–C950, 2007). The aim of the present study was to further examine this oxidant-impaired inhibition of the PMCA, focusing on the role of the mitochondria. Using a [Ca2+]i clearance assay in which mitochondrial Ca2+ uptake was blocked with Ru-360, H2O2 (50 μM–1 mM) markedly inhibited the PMCA activity. This H2O2-induced inhibition of the PMCA correlated with mitochondrial depolarization (assessed using tetramethylrhodamine methylester fluorescence) but could occur without significant ATP depletion (assessed using Magnesium Green fluorescence). The H2O2-induced PMCA inhibition was sensitive to the mitochondrial permeability transition pore (mPTP) inhibitors, cyclosporin-A and bongkrekic acid. These data suggest that oxidant-induced opening of the mPTP and mitochondrial depolarization may lead to an inhibition of the PMCA that is independent of mitochondrial Ca2+ handling and ATP depletion, and we speculate that this may involve the release of a mitochondrial factor. Such a phenomenon may be responsible for the Ca2+ overload response, and for the transition between apoptotic and necrotic cell death thought to be important in many disease states.


2007 ◽  
Vol 293 (3) ◽  
pp. C938-C950 ◽  
Author(s):  
Jason I. E. Bruce ◽  
Austin C. Elliott

Pancreatitis is an inflammatory disease of pancreatic acinar cells whereby intracellular calcium concentration ([Ca2+]i) signaling and enzyme secretion are impaired. Increased oxidative stress has been suggested to mediate the associated cell injury. The present study tested the effects of the oxidant, hydrogen peroxide, on [Ca2+]i signaling in rat pancreatic acinar cells by simultaneously imaging fura-2, to measure [Ca2+]i, and dichlorofluorescein, to measure oxidative stress. Millimolar concentrations of hydrogen peroxide increased cellular oxidative stress and irreversibly increased [Ca2+]i, which was sensitive to antioxidants and removal of external Ca2+, and ultimately led to cell lysis. Responses were also abolished by pretreatment with (sarco)endoplasmic reticulum Ca2+-ATPase inhibitors, unless cells were prestimulated with cholecystokinin to promote mitochondrial Ca2+ uptake. This suggests that hydrogen peroxide promotes Ca2+ release from the endoplasmic reticulum and the mitochondria and that it promotes Ca2+ influx. Lower concentrations of hydrogen peroxide (10–100 μM) increased [Ca2+]i and altered cholecystokinin-evoked [Ca2+]i oscillations with marked heterogeneity, the severity of which was directly related to oxidative stress, suggesting differences in cellular antioxidant capacity. These changes in [Ca2+]i also upregulated the activity of the plasma membrane Ca2+-ATPase in a Ca2+-dependent manner, whereas higher concentrations (0.1–1 mM) inactivated the plasma membrane Ca2+-ATPase. This may be important in facilitating “Ca2+ overload,” resulting in cell injury associated with pancreatitis.


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