title: Increase of intracellular Ca(2+) during ischemia/reperfusion injury of heart is mediated by cyclic ADP-ribose.
abstract: While the molecular mechanisms by which oxidants cause cytotoxicity are still poorly understood, disruption of Ca(2+) homeostasis appears to be one of the critical alterations during the oxidant-induced cytotoxic process. Here, we examined the possibility that oxidative stress may alter the metabolism of cyclic ADP-ribose (cADPR), a potent Ca(2+)-mobilizing second messenger in the heart. Isolated heart perfused by Langendorff technique was subjected to ischemia/reperfusion injury and endogenous cADPR level was determined using a specific radioimmunoassay. Following ischemia/reperfusion injury, a significant increase in intracellular cADPR level was observed. The elevation of cADPR content was closely correlated with the increase in ADP-ribosyl cyclase activity. Inclusion of oxygen free radical scavengers, 2,2,6,6-tetramethyl-1-piperidinyloxy and mannitol, in the reperfusate prevented the ischemia/reperfusion-induced increases in cADPR level and the ADP-ribosyl cyclase activity. Exposure of isolated cardiomyocytes to t-butyl hydroperoxide increased the ADP-ribosyl cyclase activity, cADPR level, and intracellular Ca(2+) concentration ([Ca(2+)](i)) and consequently resulting in cell lethal damage. The oxidant-induced elevation of [Ca(2+)](i) as well as cell lethal damage was blocked by a cADPR antagonist, 8-bromo-cADPR. These results provide evidence for involvement of cADPR and its producing enzyme in alteration of Ca(2+) homeostasis during the ischemia/reperfusion injury of the heart.
authors.affiliation: Department of Biochemistry, Chonbuk National University Medical School, Chonju 561-182, South Korea.
authors.forename: Guang-Hua
authors.initials: GH
authors.lastname: Xie
authors.forename: So-Young
authors.initials: SY
authors.lastname: Rah
authors.forename: Kye Sook
authors.initials: KS
authors.lastname: Yi
authors.forename: Myung Kwan
authors.initials: MK
authors.lastname: Han
authors.forename: Soo Wan
authors.initials: SW
authors.lastname: Chae
authors.forename: Mie-Jae
authors.initials: MJ
authors.lastname: Im
authors.forename: Uh-Hyun
authors.initials: UH
authors.lastname: Kim
mesh_terms: D036541:ADP-ribosyl Cyclase / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002470:Cell Survival; D002478:Cells, Cultured; D036563:Cyclic ADP-Ribose / Q000378:metabolism*; D016166:Free Radical Scavengers / Q000494:pharmacology; D006321:Heart / Q000187:drug effects; D015428:Myocardial Reperfusion Injury / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism; D009924:Organ Culture Techniques; D018384:Oxidative Stress; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D015290:Second Messenger Systems
chemical_list: D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D036563:Cyclic ADP-Ribose; D036541:ADP-ribosyl Cyclase; D002118:Calcium