Mechanism of sphingosine-1-phosphate induced cardioprotection against I/R injury in diabetic rat heart: Possible involvement of glycogen synthase kinase 3βand mitochondrial permeability transition pore

2016 ◽  
Vol 43 (2) ◽  
pp. 166-173 ◽  
Author(s):  
Ajay Rana ◽  
Saurabh Sharma
Keyword(s):  
Rat Heart ◽  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Glycogen Synthase ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Glycogen Synthase Kinase ◽  
Diabetic Rat ◽  
Mitochondrial Permeability ◽  
Sphingosine 1 Phosphate

scholarly journals Phosphorylation of GSK-3β Mediates Intralipid-induced Cardioprotection against Ischemia/Reperfusion Injury

2011 ◽  
Vol 115 (2) ◽  
pp. 242-253 ◽  
Author(s):  
Siamak Rahman ◽  
Jingyuan Li ◽  
Jean Chrisostome Bopassa ◽  
Soban Umar ◽  
Andrea Iorga ◽  
...  
Keyword(s):  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Glycogen Synthase ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Glycogen Synthase Kinase ◽  
Control Group ◽  
Glycogen Synthase Kinase 3Β ◽  
Mitochondrial Permeability

Background Intralipid (Sigma, St. Louis, MO), a brand name for the first safe fat emulsion for human use, has been shown to be cardioprotective. However, the mechanism of this protection is not known. The authors investigated the molecular mechanism(s) of Intralipid-induced cardioprotection against ischemia/reperfusion injury, particularly the role of glycogen synthase kinase-3β (GSK-3β) and mitochondrial permeability transition pore in this protective action. Methods In vivo rat hearts or isolated Langendorff-perfused mouse hearts were subjected to ischemia followed by reperfusion with Intralipid (1% in ex vivo and one bolus of 20% in in vivo) or vehicle. The hemodynamic function, infarct size, threshold for the opening of mitochondrial permeability transition pore, and phosphorylation levels of protein kinase B (Akt)/extracellular signal regulating kinase (ERK)/GSK-3β were measured. Results Administration of Intralipid at the onset of reperfusion resulted in approximately 70% reduction in infarct size in the in vivo rat model. Intralipid also significantly improved functional recovery of isolated Langendorff-perfused mouse hearts as the rate pressure product was increased from 2,999 ± 863 mmHg*beats/min in the control group to 13,676 ± 611 mmHg*beats/min (mean±SEM) and the infarct size was markedly smaller (18.3 ± 2.4% vs. 54.8 ± 2.9% in the control group, P < 0.01). The Intralipid-induced cardioprotection was fully abolished by LY294002, a specific inhibitor of PI3K, but only partially by PD98059, a specific ERK inhibitor. Intralipid also increased the phosphorylation levels of Akt/ERK1/glycogen synthase kinase-3β by eightfold, threefold, and ninefold, respectively. The opening of mitochondrial permeability transition pore was inhibited by Intralipid because calcium retention capacity was higher in the Intralipid group (274.3 ± 8.4 nM/mg vs. 168.6 ± 9.6 nM/mg in the control group). Conclusions Postischemic treatment with Intralipid inhibits the opening of mitochondiral permeability transition pore and protects the heart through glycogen synthase kinase-3β via PI3K/Akt/ERK pathways.

Isoflurane Postconditioning Prevents Opening of the Mitochondrial Permeability Transition Pore through Inhibition of Glycogen Synthase Kinase 3β

2005 ◽  
Vol 103 (5) ◽  
pp. 987-995 ◽  
Author(s):  
Jianhua Feng ◽  
Eliana Lucchinetti ◽  
Preeti Ahuja ◽  
Thomas Pasch ◽  
Jean-Claude Perriard ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Glycogen Synthase ◽  
Protein Kinase B ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Glycogen Synthase Kinase ◽  
Mitochondrial Permeability ◽  
Glycogen Synthase Kinase 3Beta

Background Postischemic administration of volatile anesthetics activates reperfusion injury salvage kinases and decreases myocardial damage. However, the mechanisms underlying anesthetic postconditioning are unclear. Methods Isolated perfused rat hearts were exposed to 40 min of ischemia followed by 1 h of reperfusion. Anesthetic postconditioning was induced by 15 min of 2.1 vol% isoflurane (1.5 minimum alveolar concentration) administered at the onset of reperfusion. In some experiments, atractyloside (10 microm), a mitochondrial permeability transition pore (mPTP) opener, and LY294002 (15 microm), a phosphatidylinositol 3-kinase inhibitor, were coadministered with isoflurane. Western blot analysis was used to determine phosphorylation of protein kinase B/Akt and its downstream target glycogen synthase kinase 3beta after 15 min of reperfusion. Myocardial tissue content of nicotinamide adenine dinucleotide served as a marker for mPTP opening. Accumulation of MitoTracker Red 580 (Molecular Probes, Invitrogen, Basel, Switzerland) was used to visualize mitochondrial function. Results Anesthetic postconditioning significantly improved functional recovery and decreased infarct size (36 +/- 1% in unprotected hearts vs. 3 +/- 2% in anesthetic postconditioning; P < 0.05). Isoflurane-mediated protection was abolished by atractyloside and LY294002. LY294002 inhibited isoflurane-induced phosphorylation of protein kinase B/Akt and glycogen synthase kinase 3beta and opened mPTP as determined by nicotinamide adenine dinucleotide measurements. Atractyloside, a direct opener of the mPTP, did not inhibit phosphorylation of protein kinase B/Akt and glycogen synthase kinase 3beta by isoflurane but reversed isoflurane-mediated cytoprotection. Microscopy showed accumulation of the mitochondrial tracker in isoflurane-protected functional mitochondria but no staining in mitochondria of unprotected hearts. Conclusions Anesthetic postconditioning by isoflurane effectively protects against reperfusion damage by preventing opening of the mPTP through inhibition of glycogen synthase kinase 3beta.

Cardioprotection of the aged rat heart by GSK-3β inhibitor is attenuated: age-related changes in mitochondrial permeability transition pore modulation

2011 ◽  
Vol 300 (3) ◽  
pp. H922-H930 ◽  
Author(s):  
Jiang Zhu ◽  
Mario J. Rebecchi ◽  
Peter S. A. Glass ◽  
Peter R. Brink ◽  
Lixin Liu
Keyword(s):  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Glycogen Synthase ◽  
Ischemia Reperfusion ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Male Rats ◽  
Mitochondrial Permeability ◽  
Mptp Opening ◽  
Gsk 3Β

It is well established that inhibition of glycogen synthase kinase (GSK)-3β in the young adult myocardium protects against ischemia-reperfusion (I/R) injury through inhibition of mitochondrial permeability transition pore (mPTP) opening. Here, we investigated age-associated differences in the ability of GSK-3β inhibitor [SB-216763 (SB)] to protect the heart and to modulate mPTP opening during I/R injury. Fischer 344 male rats were assigned from their respective young or old age groups. Animals were subjected to 30 min ischemia following 120 min reperfusion to determine myocardial infarction (MI) size in vivo. Ischemic tissues were collected 10 min after reperfusion for nicotinamide adenine dinucleotide (NAD+) measurements and immunoblotting. In parallel experiments, ventricular myocytes isolated from young or old rats were exposed to oxidative stress through generation of reactive oxygen species (ROS), and mPTP opening times were measured by using confocal microscopy. Our results showed that SB decreased MI in young SB-treated rats compared with young untreated I/R animals, whereas SB failed to significantly affect MI in the old animals. SB also significantly increased GSK-3β phosphorylation in young rats, but phosphorylation levels were already highly elevated in old control groups. There were no significant differences observed between SB-treated and untreated old animals. NAD+levels were better maintained in young SB-treated animals compared with the young untreated group during I/R, but this relative improvement was not observed in old animals. SB also significantly prolonged the time to mPTP opening induced by ROS in young cardiomyocytes, but not in aged cardiomyocytes. These results demonstrate that this GSK-3β inhibitor fails to protect the aged myocardium in response to I/R injury or prevent mPTP opening following a rise in ROS and suggest that healthy aging alters mPTP regulation by GSK-3β.

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