XOD-catalyzed ROS generation mobilizes calcium from intracellular stores in mouse pancreatic acinar cells.
In fura-2 loaded isolated mouse pancreatic acinar cells, xanthine oxidase (XOD)-catalyzed reactive oxygen species (ROS) generation caused an increase in the cytosolic Ca(2+) concentration ([Ca(2+)](i)) by release of Ca(2+) from intracellular stores. The ROS-induced Ca(2+) signals showed large variability in shape and time-course and resembled in part Ca(2+) signals in response to physiological secretagogues. ROS-induced Ca(2+) mobilization started at the luminal cell pole and spread towards the basolateral side in a wave manner. ROS-evoked Ca(2+) responses were not inhibited by the phospholipase C (PLC) inhibitor U73122 (10 microM). Neither 2-aminoethoxy-diphenylborate (2-APB) (70 microM) nor ryanodine (50 microM) suppressed ROS-evoked Ca(2+) release. ROS still released Ca(2+) when the endoplasmic reticulum Ca(2+)-ATPase was blocked with thapsigargin (1 microM), or when rotenone (10 microM) was added to release Ca(2+) from mitochondria. Our results suggest that pancreatic acinar cells ROS do not unspecifically affect Ca(2+) homeostasis. ROS primarily affect Ca(2+) stores located in the luminal cell pole, which is also the trigger zone for agonist-induced Ca(2+) signals. Release of Ca(2+) induces Ca(2+) waves carried by Ca(2+)-induced Ca(2+) release and produces thereby global Ca(2+) signals. Under oxidative stress conditions, the increase in [Ca(2+)](i) could be one mechanism contributing to an overstimulation of the cell which could result in cell dysfunction and cell damage.
González
Antonio
A
Department of Physiology, Faculty of Veterinary Sciences, University of Extremadura, P.O. Box 643 10071, Cáceres, Spain. agmateos@unex.es
Schmid
Andreas
A
Salido
Ginés M
GM
Camello
Pedro J
PJ
Pariente
José A
JA
D000818:Animals; D001896:Boron Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000737:chemistry; D016257:Fura-2 / Q000737:chemistry; D007700:Kinetics; D008297:Male; D051379:Mice; D010179:Pancreas / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D011760:Pyrrolidinones / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012433:Ryanodine / Q000494:pharmacology; D012844:Sincalide / Q000494:pharmacology; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000502:physiology; D014969:Xanthine Oxidase / Q000378:metabolism* / Q000494:pharmacology
D001896:Boron Compounds; D004791:Enzyme Inhibitors; D004963:Estrenes; D005456:Fluorescent Dyes; D011760:Pyrrolidinones; D017382:Reactive Oxygen Species; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D012433:Ryanodine; C109986:2-aminoethoxydiphenyl borate; D014969:Xanthine Oxidase; D010738:Type C Phospholipases; D012844:Sincalide; D002118:Calcium; D016257:Fura-2