Role of Pancreatitis-Associated Protein 1 on Oxidative Stress-Induced Cell Death of Pancreatic Acinar Cells

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.

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Oxidant-impaired intracellular Ca2+ signaling in pancreatic acinar cells: role of the plasma membrane Ca2+-ATPase

AJP Cell Physiology ◽

10.1152/ajpcell.00582.2006 ◽

2007 ◽

Vol 293 (3) ◽

pp. C938-C950 ◽

Cited By ~ 37

Author(s):

Jason I. E. Bruce ◽

Austin C. Elliott

Keyword(s):

Oxidative Stress ◽

Hydrogen Peroxide ◽

Endoplasmic Reticulum ◽

Plasma Membrane ◽

Cell Injury ◽

Acinar Cells ◽

Pancreatic Acinar Cells ◽

Dependent Manner ◽

Atpase Inhibitors

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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Protective Effect of Lycopene on Oxidative Stress-Induced Cell Death of Pancreatic Acinar Cells

Annals of the New York Academy of Sciences ◽

10.1111/j.1749-6632.2009.04712.x ◽

2009 ◽

Vol 1171 (1) ◽

pp. 570-575 ◽

Cited By ~ 19

Author(s):

Jeong Yeon Seo ◽

Atsushi Masamune ◽

Tooru Shimosegawa ◽

Hyeyoung Kim

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Protective Effect ◽

Acinar Cells ◽

Pancreatic Acinar Cells

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The role of endoplasmic reticulum calcium pumps during cytosolic calcium spiking in pancreatic acinar cells.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)41521-9 ◽

1993 ◽

Vol 268 (30) ◽

pp. 22262-22264

Author(s):

C.C. Petersen ◽

O.H. Petersen ◽

M.J. Berridge

Keyword(s):

Endoplasmic Reticulum ◽

Acinar Cells ◽

Cytosolic Calcium ◽

Pancreatic Acinar Cells ◽

Endoplasmic Reticulum Calcium ◽

Calcium Pumps ◽

Calcium Spiking

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Role of hepcidin in oxidative stress and cell death of cultured mouse renal collecting duct cells: protection against iron and sensitization to cadmium

Archives of Toxicology ◽

10.1007/s00204-021-03106-z ◽

2021 ◽

Author(s):

Stephanie Probst ◽

Johannes Fels ◽

Bettina Scharner ◽

Natascha A. Wolff ◽

Eleni Roussa ◽

...

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Cell Fate ◽

Catalase Activity ◽

Metal Ion ◽

Iron Homeostasis ◽

Collecting Duct ◽

Duct Cell ◽

Plasmid Transfection

AbstractThe liver hormone hepcidin regulates systemic iron homeostasis. Hepcidin is also expressed by the kidney, but exclusively in distal nephron segments. Several studies suggest hepcidin protects against kidney damage involving Fe2+ overload. The nephrotoxic non-essential metal ion Cd2+ can displace Fe2+ from cellular biomolecules, causing oxidative stress and cell death. The role of hepcidin in Fe2+ and Cd2+ toxicity was assessed in mouse renal cortical [mCCD(cl.1)] and inner medullary [mIMCD3] collecting duct cell lines. Cells were exposed to equipotent Cd2+ (0.5–5 μmol/l) and/or Fe2+ (50–100 μmol/l) for 4–24 h. Hepcidin (Hamp1) was transiently silenced by RNAi or overexpressed by plasmid transfection. Hepcidin or catalase expression were evaluated by RT-PCR, qPCR, immunoblotting or immunofluorescence microscopy, and cell fate by MTT, apoptosis and necrosis assays. Reactive oxygen species (ROS) were detected using CellROX™ Green and catalase activity by fluorometry. Hepcidin upregulation protected against Fe2+-induced mIMCD3 cell death by increasing catalase activity and reducing ROS, but exacerbated Cd2+-induced catalase dysfunction, increasing ROS and cell death. Opposite effects were observed with Hamp1 siRNA. Similar to Hamp1 silencing, increased intracellular Fe2+ prevented Cd2+ damage, ROS formation and catalase disruption whereas chelation of intracellular Fe2+ with desferrioxamine augmented Cd2+ damage, corresponding to hepcidin upregulation. Comparable effects were observed in mCCD(cl.1) cells, indicating equivalent functions of renal hepcidin in different collecting duct segments. In conclusion, hepcidin likely binds Fe2+, but not Cd2+. Because Fe2+ and Cd2+ compete for functional binding sites in proteins, hepcidin affects their free metal ion pools and differentially impacts downstream processes and cell fate.

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