401
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Sudheesh NP, Ajith TA, Janardhanan KK. Ganoderma lucidum (Fr.) P. Karst enhances activities of heart mitochondrial enzymes and respiratory chain complexes in the aged rat. Biogerontology 2009; 10:627-36. [PMID: 19123066 DOI: 10.1007/s10522-008-9208-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Accepted: 12/16/2008] [Indexed: 10/21/2022]
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402
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Kondo Y, Sasaki T, Sato Y, Amano A, Aizawa S, Iwama M, Handa S, Shimada N, Fukuda M, Akita M, Lee J, Jeong KS, Maruyama N, Ishigami A. Vitamin C depletion increases superoxide generation in brains of SMP30/GNL knockout mice. Biochem Biophys Res Commun 2008; 377:291-6. [DOI: 10.1016/j.bbrc.2008.09.132] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2008] [Accepted: 09/29/2008] [Indexed: 10/21/2022]
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403
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Nguyen T, Ogbi M, Johnson JA. Delta protein kinase C interacts with the d subunit of the F1F0 ATPase in neonatal cardiac myocytes exposed to hypoxia or phorbol ester. Implications for F1F0 ATPase regulation. J Biol Chem 2008; 283:29831-40. [PMID: 18725417 PMCID: PMC2573058 DOI: 10.1074/jbc.m801642200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Revised: 08/06/2008] [Indexed: 11/06/2022] Open
Abstract
Mitochondrial protein kinase C isozymes have been reported to mediate both cardiac ischemic preconditioning and ischemia/reperfusion injury. In addition, cardiac preconditioning improves the recovery of ATP levels after ischemia/reperfusion injury. We have, therefore, evaluated protein kinase C modulation of the F(1)F(0) ATPase in neonatal cardiac myocytes. Exposure of cells to 3 or 100 nM 4beta-phorbol 12-myristate-13-acetate induced co-immunoprecipitation of delta protein kinase C (but not alpha, epsilon, or zeta protein kinase C) with the d subunit of the F(1)F(0) ATPase. This co-immunoprecipitation correlated with 40+/-3% and 72+/-9% inhibitions of oligomycin-sensitive F(1)F(0) ATPase activity, respectively. We observed prominent expression of delta protein kinase C in cardiac myocyte mitochondria, which was enhanced following a 4-h hypoxia exposure. In contrast, hypoxia decreased mitochondrial zetaPKC levels by 85+/-1%. Following 4 h of hypoxia, F(1)F(0) ATPase activity was inhibited by 75+/-9% and delta protein kinase C co-immunoprecipitated with the d subunit of F(1)F(0) ATPase. In vitro incubation of protein kinase C with F(1)F(0) ATPase enhanced F(1)F(0) activity in the absence of protein kinase C activators and inhibited it in the presence of activators. Recombinant delta protein kinase C also inhibited F(1)F(0) ATPase activity. Protein kinase C overlay assays revealed delta protein kinase C binding to the d subunit of F(1)F(0) ATPase, which was modulated by diacylglycerol, phosphatidylserine, and cardiolipin. Our results suggest a novel regulation of the F(1)F(0) ATPase by the delta protein kinase C isozyme.
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Affiliation(s)
- Tiffany Nguyen
- Department of Pharmacology and Toxicology, School of Medicine, Medical College of Georgia, Augusta, Georgia 30912-2300, USA
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404
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Wojtovich AP, Burwell LS, Sherman TA, Nehrke KW, Brookes PS. The C. elegans mitochondrial K+(ATP) channel: a potential target for preconditioning. Biochem Biophys Res Commun 2008; 376:625-8. [PMID: 18809388 DOI: 10.1016/j.bbrc.2008.09.043] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 09/11/2008] [Accepted: 09/11/2008] [Indexed: 10/21/2022]
Abstract
Ischemic preconditioning (IPC) is an evolutionarily conserved endogenous mechanism whereby short periods of non-lethal exposure to hypoxia alleviate damage caused by subsequent ischemia reperfusion (IR). Pharmacologic targeting has suggested that the mitochondrial ATP-sensitive potassium channel (mK(ATP)) is central to IPC signaling, despite its lack of molecular identity. Here, we report that isolated Caenorhabditis elegans mitochondria have a K(ATP) channel with the same physiologic and pharmacologic characteristics as the vertebrate channel. Since C. elegans also exhibit IPC, our observations provide a framework to study the role of mK(ATP) in IR injury in a genetic model organism.
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Affiliation(s)
- Andrew P Wojtovich
- Department of Pharmacology & Physiology, Box 604, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
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405
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Korge P, Ping P, Weiss JN. Reactive oxygen species production in energized cardiac mitochondria during hypoxia/reoxygenation: modulation by nitric oxide. Circ Res 2008; 103:873-80. [PMID: 18776040 DOI: 10.1161/circresaha.108.180869] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mitochondria are an important source of reactive oxygen species (ROS), implicated in ischemia/reperfusion injury. When isolated from ischemic myocardium, mitochondria demonstrate increased ROS production as a result of damage to electron transport complexes. To investigate the mechanisms, we studied effects of hypoxia/reoxygenation on ROS production by isolated energized heart mitochondria. ROS production, tracked using Fe(2+)-catalyzed, H(2)O(2)-dependent H(2)DCF oxidation or Amplex Red, was similar during normoxia and hypoxia but markedly increased during reoxygenation, in proportion to the duration of hypoxia. In contrast, if mitochondria were rapidly converted from normoxia to near-anoxia ([O(2)], <1 micromol/L), the increase in H(2)DCF oxidation rate during reoxygenation was markedly blunted. To elicit the robust increase in H(2)DCF oxidation rate during reoxygenation, hypoxia had to be severe enough to cause partial, but not complete, respiratory chain inhibition (as shown by partial dissipation of membrane potential and increased NADH autofluorescence). Consistent with its cardioprotective actions, nitric oxide ( O) abrogated increased H(2)DCF oxidation under these conditions, as well as attenuating ROS-induced increases in matrix [Fe(2+)] and aconitase inhibition caused by antimycin. Collectively, these results suggest that (1) hypoxia that is sufficient to cause partial respiratory inhibition is more damaging to mitochondria than near-anoxia; and (2) O suppresses ROS-induced damage to electron transport complexes, probably by forming O-Fe(2+) complexes in the presence of glutathione, which inhibit hydroxyl radical formation.
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Affiliation(s)
- Paavo Korge
- Cardiovascular Research Laboratory, Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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406
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Schönfeld P, Wojtczak L. Fatty acids as modulators of the cellular production of reactive oxygen species. Free Radic Biol Med 2008; 45:231-41. [PMID: 18482593 DOI: 10.1016/j.freeradbiomed.2008.04.029] [Citation(s) in RCA: 314] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 04/16/2008] [Accepted: 04/22/2008] [Indexed: 12/17/2022]
Abstract
Long-chain nonesterified ("free") fatty acids (FFA) and some of their derivatives and metabolites can modify intracellular production of reactive oxygen species (ROS), in particular O(2)(-) and H(2)O(2). In mitochondria, FFA exert a dual effect on ROS production. Because of slowing down the rate of electron flow through Complexes I and III of the respiratory chain due to interaction within the complex subunit structure, and between Complexes III and IV due to release of cytochrome c from the inner membrane, FFA increase the rate of ROS generation in the forward mode of electron transport. On the other hand, due to their protonophoric action on the inner mitochondrial membrane ("mild uncoupling effect"), FFA strongly decrease ROS generation in the reverse mode of electron transport. In the plasma membrane of phagocytic neutrophils and a number of other types of cells, polyunsaturated FFA stimulate O(2)(-) generation by NADPH oxidase. These effects of FFA can modulate signaling functions of ROS and be, at least partly, responsible for their proapoptotic effects in several types of cells.
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Affiliation(s)
- Peter Schönfeld
- Institute of Biochemistry and Cell Biology, Otto von Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany.
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407
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Kewalramani G, Puthanveetil P, Kim MS, Wang F, Lee V, Hau N, Beheshti E, Ng N, Abrahani A, Rodrigues B. Acute dexamethasone-induced increase in cardiac lipoprotein lipase requires activation of both Akt and stress kinases. Am J Physiol Endocrinol Metab 2008; 295:E137-47. [PMID: 18460599 DOI: 10.1152/ajpendo.00004.2008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Following dexamethasone (DEX), cardiac energy generation is mainly through utilization of fatty acids (FA), with DEX animals demonstrating an increase in coronary lipoprotein lipase (LPL), an enzyme that hydrolyzes lipoproteins to FA. We examined the mechanisms by which DEX augments cardiac LPL. DEX was injected in rats, and hearts were removed, or isolated cardiomyocytes were incubated with DEX (0-8 h), for measurement of LPL activity and Western blotting. Acute DEX induced whole body insulin resistance, likely an outcome of a decrease in insulin signaling in skeletal muscle, but not cardiac tissue. The increase in luminal LPL activity after DEX was preceded by rapid nongenomic alterations, which included phosphorylation of AMPK and p38 MAPK, that led to phosphorylation of heat shock protein (HSP)25 and actin cytoskeleton rearrangement, facilitating LPL translocation to the myocyte cell surface. Unlike its effects in vivo, although DEX activated AMPK and p38 MAPK in cardiomyocytes, there was no phosphorylation of HSP25, nor was there any evidence of F-actin polymerization or an augmentation of LPL activity up to 8 h after DEX. Combining DEX with insulin appreciably enhanced cardiomyocyte LPL activity, which closely mirrored a robust elevation in phosphorylation of HSP25 and F-actin polymerization. Silencing of p38 MAPK, inhibition of PI 3-kinase, or preincubation with cytochalasin D prevented the increases in LPL activity. Our data suggest that, following DEX, it is a novel, rapid, nongenomic phosphorylation of stress kinases that, together with insulin, facilitates LPL translocation to the myocyte cell surface.
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Affiliation(s)
- Girish Kewalramani
- Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
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408
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Lesnefsky EJ, Hoppel CL. Cardiolipin as an oxidative target in cardiac mitochondria in the aged rat. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:1020-7. [PMID: 18515061 DOI: 10.1016/j.bbabio.2008.05.444] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Revised: 05/21/2008] [Accepted: 05/22/2008] [Indexed: 02/07/2023]
Abstract
The aged heart sustains greater injury during ischemia (ISC) and reperfusion (REP) compared to the adult heart. In the Fischer 344 (F344) rat, aging decreases oxidative phosphorylation and complex III activity increasing the production of reactive oxygen species in interfibrillar mitochondria (IFM) located among the myofibrils. In the isolated, perfused 24 month old elderly F344 rat heart 25 min of stop-flow ISC causes additional damage to complex III, further decreasing the rate of oxidative phosphorylation. We did not observe further progressive mitochondrial damage during REP. We next asked if ISC or REP increased oxidative damage within mitochondria of the aged heart. Cardiolipin (CL) is a phospholipid unique to mitochondria consisting predominantly of four linoleic acid residues (C18:2). Following ISC and REP in the aged heart, there is a new CL species containing three oxygen atoms added to one linoleic residue. ISC alone was sufficient to generate this new oxidized molecular species of CL. Based upon oxidative damage to CL, complex III activity, and oxidative phosphorylation, mitochondrial damage thus occurs in the aged heart mainly during ISC, rather than during REP. Mitochondrial damage during ischemia sets the stage for mitochondrial-driven cardiomyocyte injury during reperfusion in the aged heart.
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Affiliation(s)
- Edward J Lesnefsky
- Department of Medicine, Division of Cardiology, Case Western Reserve University, Cleveland, Ohio 44106, USA
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409
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Jeanes HL, Tabor C, Black D, Ederveen A, Gray GA. Oestrogen-mediated cardioprotection following ischaemia and reperfusion is mimicked by an oestrogen receptor (ER)alpha agonist and unaffected by an ER beta antagonist. J Endocrinol 2008; 197:493-501. [PMID: 18492815 PMCID: PMC2386536 DOI: 10.1677/joe-08-0071] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Oestrogen protects the heart from ischaemic injury. The current study aims to characterise two novel oestrogen receptor (ER) ligands, an ER alpha agonist ERA-45 and an ER beta antagonist ERB-88, and then use them to investigate the roles of ER alpha and ER beta in mediating the cardioprotection by E from ischaemia-reperfusion injury in the rat. The ER ligands were characterised by gene transactivation assay using ER-transfected Chinese hamster ovary (CHO) cells and in bioavailability studies in vivo. Female rats (n=48) were ovariectomised and implanted with 17beta-oestradiol (17 beta E(2)) releasing or placebo pellets. ERA-45, ERB-88 or vehicle was administered for 5 days prior to ischaemia-reperfusion studies. Necrosis, neutrophil infiltration (myeloperoxidase activity) and oxidant stress production (electron paramagnetic resonance) from the area-at-risk were measured to assess reperfusion injury. The ER alpha agonist ERA-45 showed more than 35-fold selectivity for ER alpha compared with ER beta gene transactivation. In vitro, the ER beta antagonist ERB-88 inhibited transactivation by 17 beta E(2) via ER beta with 46-fold selectivity relative to inhibition via ER alpha. In vivo, 17 beta E(2) significantly reduced neutrophil infiltration, oxidant stress and necrosis following ischaemia and reperfusion. Cardioprotection by 17 beta E(2) was not inhibited by ERB-88 but was completely reproduced by ERA-45. In conclusion, protection of the rat heart after ischaemia-reperfusion by 17 beta E(2) is achieved through the reduction of cardiomyocyte death, neutrophil infiltration and oxygen-free radical availability.The results of this study indicate that these effects are primarily mediated via activation of ER alpha.
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Affiliation(s)
| | | | - Darcey Black
- Organon Laboratories LtdDepartment PharmacologyNewhouse, Lanarkshire, Scotland, ML1 5SHUK
| | - Antwan Ederveen
- Department PharmacologyNV OrganonPO Box 20, 5340 BH OssThe Netherlands
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410
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Zhang J, Liem DA, Mueller M, Wang Y, Zong C, Deng N, Vondriska TM, Korge P, Drews O, MacLellan WR, Honda H, Weiss JN, Apweiler R, Ping P. Altered proteome biology of cardiac mitochondria under stress conditions. J Proteome Res 2008; 7:2204-14. [PMID: 18484766 PMCID: PMC3805274 DOI: 10.1021/pr070371f] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Myocardial ischemia-reperfusion induces mitochondrial dysfunction and, depending upon the degree of injury, may lead to cardiac cell death. However, our ability to understand mitochondrial dysfunction has been hindered by an absence of molecular markers defining the various degrees of injury. To address this paucity of knowledge, we sought to characterize the impact of ischemic damage on mitochondrial proteome biology. We hypothesized that ischemic injury induces differential alterations in various mitochondrial subcompartments, that these proteomic changes are specific to the severity of injury, and that they are important to subsequent cellular adaptations to myocardial ischemic injury. Accordingly, an in vitro model of cardiac mitochondria injury in mice was established to examine two stress conditions: reversible injury (induced by mild calcium overload) and irreversible injury (induced by hypotonic stimuli). Both forms of injury had a drastic impact on the proteome biology of cardiac mitochondria. Altered mitochondrial function was concomitant with significant protein loss/shedding from the injured organelles. In the setting of mild calcium overload, mitochondria retained functionality despite the release of numerous proteins, and the majority of mitochondria remained intact. In contrast, hypotonic stimuli caused severe damage to mitochondrial structure and function, induced increased oxidative modification of mitochondrial proteins, and brought about detrimental changes to the subproteomes of the inner mitochondrial membrane and matrix. Using an established in vivo murine model of regional myocardial ischemic injury, we validated key observations made by the in vitro model. This preclinical investigation provides function and suborganelle location information on a repertoire of cardiac mitochondrial proteins sensitive to ischemia reperfusion stress and highlights protein clusters potentially involved in mitochondrial dysfunction in the setting of ischemic injury.
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Affiliation(s)
- Jun Zhang
- Departments of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Medicine/Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - David A. Liem
- Departments of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Medicine/Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | | | - Yueju Wang
- Departments of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Medicine/Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Chenggong Zong
- Departments of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Medicine/Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Ning Deng
- Departments of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Medicine/Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Thomas M. Vondriska
- Medicine/Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Anesthesiology/Division of Molecular Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Paavo Korge
- Departments of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Oliver Drews
- Departments of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Medicine/Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - W. Robb MacLellan
- Departments of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Medicine/Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Henry Honda
- Departments of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Medicine/Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - James N. Weiss
- Departments of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Medicine/Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | | | - Peipei Ping
- Departments of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Medicine/Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
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411
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Adebiyi A, McNally EM, Jaggar JH. Sulfonylurea receptor-dependent and -independent pathways mediate vasodilation induced by ATP-sensitive K+ channel openers. Mol Pharmacol 2008; 74:736-43. [PMID: 18511652 DOI: 10.1124/mol.108.048165] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
ATP-sensitive K+ (KATP) channel openers are vasodilators that activate both plasma membrane and mitochondrial KATP channels. Here, we investigated the molecular mechanisms by which diazoxide and pinacidil induce vasodilation by studying diameter regulation of wild-type [SUR2(+/+)] and sulfonylurea receptor (SUR) 2-deficient [SUR2(-/-)] mouse myogenic mesenteric arteries. Ryanodine (10 microM), a ryanodine-sensitive Ca2+ release (RyR) channel blocker; iberiotoxin (100 nM), a large-conductance Ca2+-activated K+ (KCa) channel blocker; 4-aminopyridine (4-AP; 1 mM), a voltage-gated K+ (KV) channel blocker; manganese(III) tetrakis(1-methyl-4-pyridyl)porphyrin (MnTMPyP; 100 microM), an antioxidant; and a combination of ryanodine and 4-AP reduced diazoxide (100 microM)-induced dilation in pressurized (60 mm Hg) SUR2(+/+) arteries by 45 to 77%. In contrast, these inhibitors did not alter pinacidil (5 microM)-induced dilation in SUR2(+/+) arteries. Reverse transcription-polymerase chain reaction indicated that SUR2B was the only SUR isoform expressed in SUR2(+/+) mesenteric artery smooth muscle cells, whereas SURs were absent in SUR2(-/-) cells. In SUR2(-/-) arteries, pinacidil-induced vasodilation was 10% of that in SUR2(+/+) arteries, whereas diazoxide-induced vasodilation was similar in SUR2(+/+) and SUR2(-/-) arteries. Atpenin (1 microM), a selective electron transport chain (ETC) complex II inhibitor, dilated arteries similarly to diazoxide, and this effect was attenuated by MnTMPyP and ryanodine + 4-AP. Atpenin also attenuated diazoxide-, but not pinacidil-induced vasodilation. In summary, data indicate that pinacidil-induced vasodilation requires SUR2B, whereas diazoxide-induced vasodilation does not require SURs. Rather, diazoxide-induced vasodilation involves ETCII inhibition; a smooth muscle cell-reactive oxygen species elevation; and RyR, KCa, and KV channel activation. These data indicate that KATP channel openers regulate arterial diameter via SUR-dependent and -independent pathways.
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Affiliation(s)
- Adebowale Adebiyi
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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412
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Zhang J, Li X, Mueller M, Wang Y, Zong C, Deng N, Vondriska TM, Liem DA, Yang JI, Korge P, Honda H, Weiss JN, Apweiler R, Ping P. Systematic characterization of the murine mitochondrial proteome using functionally validated cardiac mitochondria. Proteomics 2008; 8:1564-75. [PMID: 18348319 DOI: 10.1002/pmic.200700851] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Mitochondria play essential roles in cardiac pathophysiology and the murine model has been extensively used to investigate cardiovascular diseases. In the present study, we characterized murine cardiac mitochondria using an LC/MS/MS approach. We extracted and purified cardiac mitochondria; validated their functionality to ensure the final preparation contains necessary components to sustain their normal function; and subjected these validated organelles to LC/MS/MS-based protein identification. A total of 940 distinct proteins were identified from murine cardiac mitochondria, among which, 480 proteins were not previously identified by major proteomic profiling studies. The 940 proteins consist of functional clusters known to support oxidative phosphorylation, metabolism, and biogenesis. In addition, there are several other clusters, including proteolysis, protein folding, and reduction/oxidation signaling, which ostensibly represent previously under-appreciated tasks of cardiac mitochondria. Moreover, many identified proteins were found to occupy other subcellular locations, including cytoplasm, ER, and golgi, in addition to their presence in the mitochondria. These results provide a comprehensive picture of the murine cardiac mitochondrial proteome and underscore tissue- and species-specification. Moreover, the use of functionally intact mitochondria insures that the proteomic observations in this organelle are relevant to its normal biology and facilitates decoding the interplay between mitochondria and other organelles.
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Affiliation(s)
- Jun Zhang
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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413
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Tominaga H, Katoh H, Odagiri K, Takeuchi Y, Kawashima H, Saotome M, Urushida T, Satoh H, Hayashi H. Different effects of palmitoyl-L-carnitine and palmitoyl-CoA on mitochondrial function in rat ventricular myocytes. Am J Physiol Heart Circ Physiol 2008; 295:H105-12. [PMID: 18469143 DOI: 10.1152/ajpheart.01307.2007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Although mitochondrial oxidative catabolism of fatty acid (FA) is a major energy source for the adult mammalian heart, cardiac lipotoxity resulting from elevated serum FA and enhanced FA use has been implicated in the pathogenesis of heart failure. To investigate the effects of intermediates of FA metabolism [palmitoyl-l-carnitine (Pal-car) and palmitoyl-CoA (Pal-CoA)] on mitochondrial function, we measured membrane potential (DeltaPsi(m)), opening of the mitochondrial permeability transition pore (mPTP), and the production of ROS in saponin-treated rat ventricular myocytes with a laser scanning confocal microscope. Our results revealed that 1) lower concentrations of Pal-car (1 and 5 muM) caused a slight hyperpolarization of DeltaPsi(m) [tetramethylrhodamine ethyl ester (TMRE) intensity increased to 115.5 +/- 5.4% and 110.7 +/- 1.6% of baseline, respectively, P < 0.05] but did not open the mPTP, 2) a higher concentration of Pal-car (10 microM) depolarized DeltaPsi(m) (TMRE intensity decreased to 61.9 +/- 12.2% of baseline, P < 0.01) and opened the mPTP (calcein intensity decreased to 70.7 +/- 2.8% of baseline, P < 0.01), 3) Pal-CoA depolarized DeltaPsi(m) without opening the mPTP, and 4) only the higher concentration of Pal-car (10 muM) increased ROS generation (2',7'-dichlorofluorescein diacetate intensity increased to 3.4 +/- 0.3-fold of baseline). We concluded that excessive exogenous intermediates of long-chain saturated FA may disturb mitochondrial function in different ways between Pal-car and Pal-CoA. The distinct mechanisms of the deteriorating effects of long-chain FA on mitochondrial function are important for our understanding of the development of cardiac diseases in systemic metabolic disorders.
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Affiliation(s)
- Hiromutsu Tominaga
- Div. of Cardiology, Internal Medicine III, Hamamatsu Univ. School of Medicine, Hamamatsu 431-3192, Japan
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414
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Haas RH, Parikh S, Falk MJ, Saneto RP, Wolf NI, Darin N, Wong LJ, Cohen BH, Naviaux RK. The in-depth evaluation of suspected mitochondrial disease. Mol Genet Metab 2008; 94:16-37. [PMID: 18243024 PMCID: PMC2810849 DOI: 10.1016/j.ymgme.2007.11.018] [Citation(s) in RCA: 252] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 11/21/2007] [Accepted: 11/21/2007] [Indexed: 12/12/2022]
Abstract
Mitochondrial disease confirmation and establishment of a specific molecular diagnosis requires extensive clinical and laboratory evaluation. Dual genome origins of mitochondrial disease, multi-organ system manifestations, and an ever increasing spectrum of recognized phenotypes represent the main diagnostic challenges. To overcome these obstacles, compiling information from a variety of diagnostic laboratory modalities can often provide sufficient evidence to establish an etiology. These include blood and tissue histochemical and analyte measurements, neuroimaging, provocative testing, enzymatic assays of tissue samples and cultured cells, as well as DNA analysis. As interpretation of results from these multifaceted investigations can become quite complex, the Diagnostic Committee of the Mitochondrial Medicine Society developed this review to provide an overview of currently available and emerging methodologies for the diagnosis of primary mitochondrial disease, with a focus on disorders characterized by impairment of oxidative phosphorylation. The aim of this work is to facilitate the diagnosis of mitochondrial disease by geneticists, neurologists, and other metabolic specialists who face the challenge of evaluating patients of all ages with suspected mitochondrial disease.
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Affiliation(s)
- Richard H. Haas
- Departments of Neurosciences & Pediatrics, University of California San Diego, La Jolla, CA and Rady Children's Hospital San Diego, San Diego, CA
- Corresponding Author: Richard H. Haas, MB, BChir, MRCP, Professor of Neurosciences and Pediatrics, University of California San Diego, T. 858-822-6700; F. 858-822-6707;
| | - Sumit Parikh
- Division of Neuroscience, The Cleveland Clinic, Cleveland, OH
| | - Marni J. Falk
- Division of Human Genetics, The Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA
| | - Russell P. Saneto
- Division of Pediatric Neurology, Children's Hospital and Regional Medical Center, University of Washington, Seattle, WA
| | - Nicole I. Wolf
- Department of Child Neurology, University Children's Hospital, Heidelberg, Germany
| | - Niklas Darin
- Division of Child Neurology, The Queen Silvia Children's Hospital, Göteborg, Sweden
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Bruce H. Cohen
- Division of Neuroscience, The Cleveland Clinic, Cleveland, OH
| | - Robert K. Naviaux
- Departments of Medicine and Pediatrics, Division of Medical and Biochemical Genetics, University of California San Diego, La Jolla, CA and Rady Children's Hospital San Diego, San Diego, CA
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415
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Agnetti G, Bezstarosti K, Dekkers DHW, Verhoeven AJM, Giordano E, Guarnieri C, Caldarera CM, Van Eyk JE, Lamers JMJ. Proteomic profiling of endothelin-1-stimulated hypertrophic cardiomyocytes reveals the increase of four different desmin species and alpha-B-crystallin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:1068-76. [PMID: 18472024 DOI: 10.1016/j.bbapap.2008.04.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 04/03/2008] [Accepted: 04/04/2008] [Indexed: 01/19/2023]
Abstract
We performed a proteomic investigation on primary cultures of neonatal rat cardiomyocytes after treatment with 10 nM endothelin-1 (ET1) for 48 h, an in vitro model for cardiac hypertrophy. Two-dimensional gel electrophoresis profiles of cell lysates were compared after colloidal Coomassie Blue staining. 12 protein spots that significantly changed in density due to ET1 stimulation were selected for in-gel digestion and identified through mass spectrometry. Of these, 8 spots were increased and 4 were decreased. Four of the increased proteins were identified as desmin, the cardiac component of intermediate filaments and one as alpha-B-crystallin, a molecular chaperone that binds desmin. All the desmins increased 2- to 5-fold, and alpha-B-crystallin increased 2-fold after ET1 treatment. Desmin cytoskeleton has been implicated in the regulation of mitochondrial activity and distribution, as well as in the formation of amyloid bodies. Mitochondria-specific fluorescent probe MitoTracker indicated mitochondrial redistribution in hypertrophic cells. An increase of amyloid aggregates containing desmin upon treatment with ET1 was detected by filter assay. Of the four proteins that showed decreased abundance after ET1 treatment, the chaperones hsp60 and grp75 were decreased 13- and 9-fold, respectively. In conclusion, proteomic profiling of ET1-stimulated rat neonatal cardiomyocytes reveals specific changes in cardiac molecular phenotype mainly involving intermediate filament and molecular chaperone proteins.
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Affiliation(s)
- Giulio Agnetti
- Department of Biochemistry G. Moruzzi, INRC, University of Bologna, Italy.
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416
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Wojtovich AP, Brookes PS. The endogenous mitochondrial complex II inhibitor malonate regulates mitochondrial ATP-sensitive potassium channels: implications for ischemic preconditioning. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:882-9. [PMID: 18433712 DOI: 10.1016/j.bbabio.2008.03.025] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Revised: 03/19/2008] [Accepted: 03/25/2008] [Indexed: 11/17/2022]
Abstract
Ischemic preconditioning (IPC) affords cardioprotection against ischemia-reperfusion (IR) injury, and while the molecular mechanisms of IPC are debated, the mitochondrial ATP-sensitive K(+) channel (mK(ATP)) has emerged as a candidate effector for several IPC signaling pathways. The molecular identity of this channel is unknown, but significant pharmacologic overlap exists between mK(ATP) and mitochondrial respiratory complex II (succinate dehydrogenase). In this investigation, we utilized isolated cardiac mitochondria, Langendorff perfused hearts, and a variety of biochemical methods, to make the following observations: (i) The competitive complex II inhibitor malonate is formed in mitochondria under conditions resembling IPC. (ii) IPC leads to a reversible inhibition of complex II that has likely been missed in previous investigations due to the use of saturating concentrations of succinate. (iii) Malonate opens mK(ATP) channels even when mitochondria are respiring on complex I-linked substrates, suggesting an effect of this inhibitor on the mK(ATP) channel independent of complex II inhibition. Together, these observations suggest that complex II inhibition by endogenously formed malonate may represent an important activation pathway for mK(ATP) channels during IPC.
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Affiliation(s)
- Andrew P Wojtovich
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642, USA
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417
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Subudhi U, Das K, Paital B, Bhanja S, Chainy GBN. Alleviation of enhanced oxidative stress and oxygen consumption of L-thyroxine induced hyperthyroid rat liver mitochondria by vitamin E and curcumin. Chem Biol Interact 2008; 173:105-14. [PMID: 18377885 DOI: 10.1016/j.cbi.2008.02.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2007] [Revised: 02/14/2008] [Accepted: 02/14/2008] [Indexed: 10/22/2022]
Abstract
In the present study, the role of vitamin E and curcumin on hyperthyroidism induced mitochondrial oxygen consumption and oxidative damage to lipids and proteins of rat liver are reported. Adult male rats were rendered hyperthyroid by administration of 0.0012% l-thyroxine in their drinking water, while vitamin E (200 mg/kg body weight) and curcumin (30 mg/kg body weight) were supplemented orally for 30 days. Hyperthyroidism induced elevation in serum aspartate aminotransferase and alanine aminotransferase activities were reduced significantly in response to vitamin E and curcumin treatment. On the other hand, effects of vitamin E and curcumin on hyperthyroidism induced hepatic complexes I and II mediated respiration were found to be different. While curcumin administration ameliorates hyperthyroidism induced state 3 and state 4 respiration in complex I, vitamin E treatment was effective only in reducing state 4 respiration of complex I. On the contrary, curcumin administration was ineffective in modulating hyperthyroidism induced complex II respiration, but vitamin E treatment to hyperthyroid rats resulted in augmentation of complex II respiration both at state 3 and state 4 level. Moreover, vitamin E and curcumin treatment resulted in alleviation of hyperthyroidism induced lipid peroxidation. Enhanced protein carbonylation in hyperthyroid rats is decreased only in response to simultaneous supplementation of vitamin E and curcumin. Above findings suggest that both vitamin E and curcumin have differential regulation on complexes I and II mediated mitochondrial respiration and have a protective role against L-thyroxine induced hepatic dysfunction and oxidative stress.
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Affiliation(s)
- U Subudhi
- Department of Biotechnology, Utkal University, Bhubaneswar 751004, Orissa, India
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418
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Abstract
It is now recognized that oxidative injury and mitochondrial dysfunction are responsible for many clinical disorders with unmet needs, including ischemia-reperfusion injury, neurodegeneration, and diabetes. Mitochondrial dysfunction can lead to cell death by apoptosis or necrosis. As mitochondria are the major source of intracellular reactive oxygen species (ROS), and mitochondria are also the primary target for ROS, the ideal drug therapy needs to be targeted to mitochondria. A number of approaches have been used for targeted delivery of therapeutic agents to mitochondria. This review will focus on a novel class of cell-permeable small peptides (Szeto-Schiller peptides) that selectively partition to the inner mitochondrial membrane and possess intrinsic mitoprotective properties. Studies with isolated mitochondrial preparations and cell cultures show that these SS peptides can scavenge ROS, reduce mitochondrial ROS production, and inhibit mitochondrial permeability transition. They are very potent in preventing apoptosis and necrosis induced by oxidative stress or inhibition of the mitochondrial electron transport chain. These peptides have demonstrated excellent efficacy in animal models of ischemia-reperfusion, neurodegeneration, and renal fibrosis, and they are remarkably free of toxicity. The pharmacology of the SS peptides in models of ischemia-reperfusion will be the focus of this review.
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Affiliation(s)
- Hazel H Szeto
- Department of Pharmacology, Joan and Sanford I. Weill Medical College of Cornell University, New York, New York 10021, USA.
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419
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Burwell LS, Brookes PS. Mitochondria as a target for the cardioprotective effects of nitric oxide in ischemia-reperfusion injury. Antioxid Redox Signal 2008; 10:579-99. [PMID: 18052718 DOI: 10.1089/ars.2007.1845] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
During cardiac ischemia-reperfusion (IR) injury, excessive generation of reactive oxygen species (ROS) and overload of Ca(2+) at the mitochondrial level both lead to opening of the mitochondrial permeability transition (PT) pore on reperfusion. This can result in the depletion of ATP, irreversible oxidation of proteins, lipids, and DNA within the cardiomyocyte, and can trigger cell-death pathways. In contrast, mitochondria are also implicated in the cardioprotective signaling processes of ischemic preconditioning (IPC), to prevent IR-related pathology. Nitric oxide (NO*) has emerged as a potent effector molecule for a variety of cardioprotective strategies, including IPC. Whereas NO* is most noted for its activation of the "classic" soluble guanylate cyclase (sGC) signaling pathway, emerging evidence indicates that NO can directly act on mitochondria, independent of the sGC pathway, affording acute cardioprotection against IR injury. These direct effects of NO* on mitochondria are the focus of this review.
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Affiliation(s)
- Lindsay S Burwell
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642, USA
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420
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Chen Q, Moghaddas S, Hoppel CL, Lesnefsky EJ. Ischemic defects in the electron transport chain increase the production of reactive oxygen species from isolated rat heart mitochondria. Am J Physiol Cell Physiol 2008; 294:C460-6. [DOI: 10.1152/ajpcell.00211.2007] [Citation(s) in RCA: 229] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cardiac ischemia decreases complex III activity, cytochrome c content, and respiration through cytochrome oxidase in subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM). The reversible blockade of electron transport with amobarbital during ischemia protects mitochondrial respiration and decreases myocardial injury during reperfusion. These findings support that mitochondrial damage occurs during ischemia and contributes to myocardial injury during reperfusion. The current study addressed whether ischemic damage to the electron transport chain (ETC) increased the net production of reactive oxygen species (ROS) from mitochondria. SSM and IFM were isolated from 6-mo-old Fisher 344 rat hearts following 25 min global ischemia or following 40 min of perfusion alone as controls. H2O2release from SSM and IFM was measured using the amplex red assay. With glutamate as a complex I substrate, the net production of H2O2was increased by 178 ± 14% and 179 ± 17% in SSM and IFM ( n = 9), respectively, following ischemia compared with controls ( n = 8). With succinate as substrate in the presence of rotenone, H2O2increased by 272 ± 22% and 171 ± 21% in SSM and IFM, respectively, after ischemia. Inhibitors of electron transport were used to assess maximal ROS production. Inhibition of complex I with rotenone increased H2O2production by 179 ± 24% and 155 ± 14% in SSM and IFM, respectively, following ischemia. Ischemia also increased the antimycin A-stimulated production of H2O2from complex III. Thus ischemic damage to the ETC increased both the capacity and the net production of H2O2from complex I and complex III and sets the stage for an increase in ROS production during reperfusion as a mechanism of cardiac injury.
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421
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Quinol type compound in cytochrome c preparations leads to non-enzymatic reduction of cytochrome c during the measurement of complex III activity. Mitochondrion 2007; 8:155-63. [PMID: 18272433 DOI: 10.1016/j.mito.2007.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2007] [Revised: 11/30/2007] [Accepted: 12/11/2007] [Indexed: 10/22/2022]
Abstract
Measurement of complex III activity is critical to the diagnosis of human mitochondrial disease and the study of mitochondrial pathobiology. Activity is measured as the maximal rate of antimycin A-sensitive reduction of exogenous cytochrome c by detergent-solubilized mitochondria. Complex III activity exhibited an unexpected variation based upon the commercial source of cytochrome c owing to an increase in the antimycin A-insensitive background reduction of cytochrome c and variable increases in total activity. Analysis of cytochrome c (producing a high-background) by fast protein liquid chromatography yielded a contaminant peak containing a lipid extractable component with redox spectra and mass spectroscopy fragmentation suggestive of a quinol. Measurement of inhibitor-sensitive rates are critical for the accurate and reproducible measurement of complex III activity and serve as a key quality control to screen for non-enzymatic reactions that obscure complex III activity.
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422
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Zini R, Berdeaux A, Morin D. The differential effects of superoxide anion, hydrogen peroxide and hydroxyl radical on cardiac mitochondrial oxidative phosphorylation. Free Radic Res 2007; 41:1159-66. [PMID: 17886038 DOI: 10.1080/10715760701635074] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The involvement of reactive oxygen species (ROS) in cardiac ischemia-reperfusion injuries is well-established, but the deleterious effects of hydrogen peroxide (H(2)O(2)), hydroxyl radical (HO*) or superoxide anion (O(2)*(-) ) on mitochondrial function are poorly understood. Here, we report that incubation of rat heart mitochondria with each of these three species resulted in a decline of the ADP-stimulated respiratory rate but not substrate-dependent respiration. These three species reduced oxygen consumption induced by an uncoupler without alteration of the respiratory chain complexes, but did not modify mitochondrial membrane permeability. HO* slightly decreased F1F0-ATPase activity and HO* and O(2)*(-) partially inhibited the activity of adenine nucleotide translocase; H(2)O(2) failed to alter these targets. They inhibited NADH production by acting specifically on aconitase for O(2)*(-) and alpha-ketoglutarate dehydrogenase for H(2)O(2) and HO*. Our results show that O(2)*(-), H(2)O(2) and HO* act on different mitochondrial targets to alter ATP synthesis, mostly through inhibition of NADH production.
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423
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Ferdinandy P, Schulz R, Baxter GF. Interaction of cardiovascular risk factors with myocardial ischemia/reperfusion injury, preconditioning, and postconditioning. Pharmacol Rev 2007; 59:418-58. [PMID: 18048761 DOI: 10.1124/pr.107.06002] [Citation(s) in RCA: 527] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Therapeutic strategies to protect the ischemic myocardium have been studied extensively. Reperfusion is the definitive treatment for acute coronary syndromes, especially acute myocardial infarction; however, reperfusion has the potential to exacerbate lethal tissue injury, a process termed "reperfusion injury." Ischemia/reperfusion injury may lead to myocardial infarction, cardiac arrhythmias, and contractile dysfunction. Ischemic preconditioning of myocardium is a well described adaptive response in which brief exposure to ischemia/reperfusion before sustained ischemia markedly enhances the ability of the heart to withstand a subsequent ischemic insult. Additionally, the application of brief repetitive episodes of ischemia/reperfusion at the immediate onset of reperfusion, which has been termed "postconditioning," reduces the extent of reperfusion injury. Ischemic pre- and postconditioning share some but not all parts of the proposed signal transduction cascade, including the activation of survival protein kinase pathways. Most experimental studies on cardioprotection have been undertaken in animal models, in which ischemia/reperfusion is imposed in the absence of other disease processes. However, ischemic heart disease in humans is a complex disorder caused by or associated with known cardiovascular risk factors including hypertension, hyperlipidemia, diabetes, insulin resistance, atherosclerosis, and heart failure; additionally, aging is an important modifying condition. In these diseases and aging, the pathological processes are associated with fundamental molecular alterations that can potentially affect the development of ischemia/reperfusion injury per se and responses to cardioprotective interventions. Among many other possible mechanisms, for example, in hyperlipidemia and diabetes, the pathological increase in reactive oxygen and nitrogen species and the use of the ATP-sensitive potassium channel inhibitor insulin secretagogue antidiabetic drugs and, in aging, the reduced expression of connexin-43 and signal transducer and activator of transcription 3 may disrupt major cytoprotective signaling pathways thereby significantly interfering with the cardioprotective effect of pre- and postconditioning. The aim of this review is to show the potential for developing cardioprotective drugs on the basis of endogenous cardioprotection by pre- and postconditioning (i.e., drug applied as trigger or to activate signaling pathways associated with endogenous cardioprotection) and to review the evidence that comorbidities and aging accompanying coronary disease modify responses to ischemia/reperfusion and the cardioprotection conferred by preconditioning and postconditioning. We emphasize the critical need for more detailed and mechanistic preclinical studies that examine car-dioprotection specifically in relation to complicating disease states. These are now essential to maximize the likelihood of successful development of rational approaches to therapeutic protection for the majority of patients with ischemic heart disease who are aged and/or have modifying comorbid conditions.
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Affiliation(s)
- Peter Ferdinandy
- Cardiovascular Research Group, Department of Biochemistry, University of Szeged, Dóm tér 9, Szeged, H-6720, Hungary.
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424
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Duan Y, Gross RA, Sheu SS. Ca2+-dependent generation of mitochondrial reactive oxygen species serves as a signal for poly(ADP-ribose) polymerase-1 activation during glutamate excitotoxicity. J Physiol 2007; 585:741-58. [PMID: 17947304 DOI: 10.1113/jphysiol.2007.145409] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial Ca(2+) uptake and poly(ADP-ribose) polymerase-1 (PARP-1) activation are both required for glutamate-induced excitotoxic neuronal death. Since activation of the glutamate receptors can induce increased levels of reactive oxygen species (ROS), we investigated the relationship of mitochondrial Ca(2+) uptake and ROS generation, and the possibility that ROS increase is a required signal for PARP-1 activation in cultured striatal neurons. Based on the spatial profile of NMDA-induced ROS generation, we found that only mitochondria showed a significant ROS increase within 30 min after NMDA receptor activation. This ROS increase was inhibited by the mitochondrial complex inhibitors rotenone and oligomycin, but not by the cytosolic phospholipase A(2) or xanthine oxidase inhibitors. Mitochondrial ROS generation was also inhibited by both removal of Ca(2+) from extracellular medium and blockage of mitochondrial Ca(2+) uptake by either a mitochondrial uncoupler or a Ca(2+) uniporter inhibitor. Furthermore, both DNA damage and PARP-1 activation induced by NMDA treatment was inhibited by blocking mitochondrial Ca(2+) uptake or by antioxidants. Our results demonstrate that ROS production during the early stage of acute excitotoxicity derives primarily from mitochondria and is Ca(2+)-dependent. More importantly, the increase of mitochondrial ROS serves as a signal for PARP-1 activation, suggesting that concomitant mitochondrial Ca(2+) uptake and PARP-1 activation constitute a unified mechanism for excitotoxic neuronal death.
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Affiliation(s)
- Yuntao Duan
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA
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425
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Elrod JW, Calvert JW, Morrison J, Doeller JE, Kraus DW, Tao L, Jiao X, Scalia R, Kiss L, Szabo C, Kimura H, Chow CW, Lefer DJ. Hydrogen sulfide attenuates myocardial ischemia-reperfusion injury by preservation of mitochondrial function. Proc Natl Acad Sci U S A 2007; 104:15560-5. [PMID: 17878306 PMCID: PMC2000503 DOI: 10.1073/pnas.0705891104] [Citation(s) in RCA: 883] [Impact Index Per Article: 51.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The recent discovery that hydrogen sulfide (H(2)S) is an endogenously produced gaseous second messenger capable of modulating many physiological processes, much like nitric oxide, prompted us to investigate the potential of H(2)S as a cardioprotective agent. In the current study, we demonstrate that the delivery of H(2)S at the time of reperfusion limits infarct size and preserves left ventricular (LV) function in an in vivo model of myocardial ischemia-reperfusion (MI-R). This observed cytoprotection is associated with an inhibition of myocardial inflammation and a preservation of both mitochondrial structure and function after I-R injury. Additionally, we show that modulation of endogenously produced H(2)S by cardiac-specific overexpression of cystathionine gamma-lyase (alpha-MHC-CGL-Tg mouse) significantly limits the extent of injury. These findings demonstrate that H(2)S may be of value in cytoprotection during the evolution of myocardial infarction and that either administration of H(2)S or the modulation of endogenous production may be of clinical benefit in ischemic disorders.
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Affiliation(s)
- John W. Elrod
- *Department of Medicine, Division of Cardiology and
- Departments of Pathology and
| | | | - Joanna Morrison
- Departments of Biology and Environmental Health Sciences, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Jeannette E. Doeller
- Departments of Biology and Environmental Health Sciences, University of Alabama at Birmingham, Birmingham, AL 35294
| | - David W. Kraus
- Departments of Biology and Environmental Health Sciences, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Ling Tao
- Departments of Emergency Medicine and
| | | | - Rosario Scalia
- Molecular Physiology and Biophysics, Thomas Jefferson University, Philadelphia, PA 19107
| | - Levente Kiss
- Department of Surgery, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103; and
| | - Csaba Szabo
- Department of Surgery, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103; and
| | - Hideo Kimura
- **National Institute of Neuroscience, Tokyo 187-8502, Japan
| | - Chi-Wing Chow
- Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - David J. Lefer
- *Department of Medicine, Division of Cardiology and
- Departments of Pathology and
- To whom correspondence should be addressed. E-mail:
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426
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Anderson TC, Li CQ, Shao ZH, Hoang T, Chan KC, Hamann KJ, Becker LB, Vanden Hoek TL. Transient and partial mitochondrial inhibition for the treatment of postresuscitation injury: getting it just right. Crit Care Med 2007; 34:S474-82. [PMID: 17114980 DOI: 10.1097/01.ccm.0000246014.19486.a1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Within minutes of reperfusing ischemic cardiomyocytes, oxidant stress dramatically increases and is associated with postresuscitation injury. Because mitochondria produce deleterious oxidants and useful metabolic substrates, utilization of electron transport chain inhibitors against reperfusion injury, though promising, must not overly compromise recovery of mitochondrial function. This study sought to further characterize the oxidant source at reperfusion and develop a strategy for therapeutic intervention by manipulation of dose, duration, and the degree of reversibility of mitochondrial inhibition. DESIGN Comparative laboratory investigation. SETTING Laboratory of a research university. SUBJECTS Embryonic chick cardiomyocytes. INTERVENTIONS Synchronously contracting chick cardiomyocytes were exposed to 1 hr of simulated ischemia and 3 hrs of reperfusion and were monitored for cell viability (propidium iodide) and oxidant generation (dichlorofluorescein). Inhibitors were administered either all course or for the first 15 mins of reperfusion. MEASUREMENTS AND MAIN RESULTS : Application of diethyldithiocarbamic acid, 2-anthracene-carboxylic acid (rhein tech), and alpha-nicotinamide adenine dinucleotide dehydrogenase (NADH) demonstrated attenuation of the oxidant burst. In addition, diethyldithiocarbamic acid (1 mM), rhein tech (0.1 microM), and alpha-NADH (20 microM) significantly attenuated cell death from a control of 49.7% +/- 6.7% to 15.7% +/- 4.7% (n = 5, p < .01), 26.1% +/- 4.1% (n = 5, p < .01), and 13.8% +/- 1.3% (n = 5, p < .001), respectively. All doses of stigmatellin attenuated reactive oxygen species, but only a 2-20 nM dose during the first 15 mins of reperfusion abrogated cell death from 53.8% +/- 3.5% to 10.8% +/- 2.9% (n = 5, p < .001). Increased doses and durations of stigmatellin abolished reactive oxygen species but augmented injury. Although rotenone (5 microM) attenuated reactive oxygen species, no dose or duration of exposure that ameliorated cell death was found. CONCLUSIONS Early events of reperfusion are marked by rapid mitochondrial oxidant generation and postresuscitation injury. Electron transport chain blockade provides an effective method of attenuating reactive oxygen species. However, inhibitor administration should be both transient and reversible to necessitate cardioprotection and successful metabolic recovery.
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Affiliation(s)
- Travis C Anderson
- Emergency Resuscitation Center, Sections of Emergency Medicine, Department of Medicine, University of Chicago, Chicago, Illinois, USA
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427
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Iwase H, Robin E, Guzy RD, Mungai PT, Vanden Hoek TL, Chandel NS, Levraut J, Schumacker PT. Nitric oxide during ischemia attenuates oxidant stress and cell death during ischemia and reperfusion in cardiomyocytes. Free Radic Biol Med 2007; 43:590-9. [PMID: 17640569 DOI: 10.1016/j.freeradbiomed.2007.05.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Revised: 04/20/2007] [Accepted: 05/11/2007] [Indexed: 10/23/2022]
Abstract
Nitric oxide (NO) has been implicated as a cardioprotective agent during ischemia/reperfusion (I/R), but the mechanism of protection is unknown. Oxidant stress contributes to cell death in I/R, so we tested whether NO protects by attenuating oxidant stress. Cardiomyocytes and murine embryonic fibroblasts were administered NO (10-1200 nM) during simulated ischemia, and cell death was assessed during reperfusion without NO. In each case, NO abrogated cell death during reperfusion. Cells overexpressing endothelial NO synthase (NOS) exhibited a similar protection, which was abolished by the NOS inhibitor N(omega)-nitro-l-arginine methyl ester. Protection was not mediated by guanylate cyclase or the mitochondrial K(ATP) channel, as inhibitors of these systems failed to abolish protection. NO did not prevent decreases in mitochondrial potential, but cells protected with NO demonstrated recovery of potential at reperfusion. Measurements using C11-BODIPY reveal that NO attenuates lipid peroxidation during ischemia and reperfusion. Measurements of oxidant stress using the ratiometric redox sensor HSP-FRET demonstrate that NO attenuates protein oxidation during ischemia. These findings reveal that physiological levels of NO during ischemia can attenuate oxidant stress both during ischemia and during reperfusion. This response is associated with a remarkable attenuation of cell death, suggesting that ischemic cell death may be a regulated event.
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Affiliation(s)
- Hirotaro Iwase
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA
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428
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Abstract
HYPOTHESIS Damage to heart mitochondrial structure and function occur with aging, and in heart failure (HF). However, the extent of mitochondrial dysfunction, the expression of mitochondrial and nuclear genes, and their cross-talk is not known. OBSERVATIONS Several observations have suggested that somatic mutations in mitochondrial DNA (mtDNA), induced by reactive oxygen species (ROS), appear to be the primary cause of energy decline, and that the generation of ROS is mainly the product of the mitochondrial respiratory chain. The free radical theory of aging, that could also be applied to HF, and in particular the targeting of mtDNA is supported by a plurality of observations from both animal and clinical studies showing decreased mitochondrial function, increased ROS levels and mtDNA mutations in the aging heart. DISCUSSION Aging and HF with their increased ROS-induced defects in mtDNA, including base modifications and frequency of mtDNA deletions, might be expected to cause increased errors or mutations in mtDNA-encoded enzyme subunits, resulting in impaired oxidative phosphorylation and defective electron transport chain (ETC) activity which in turn creates more ROS. These events in both the aging and failing heart involve substantial nuclear-mitochondrial interaction, which is further illustrated in the progression of myocardial apoptosis. In this review the cross-talk between the nucleus and the mitochondrial organelle will be examined based on a number of animal and clinical studies, including our own.
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Affiliation(s)
- José Marín-García
- The Molecular Cardiology and Neuromuscular Institute, Highland Park, NJ 08904, USA.
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429
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Yitzhaki S, Hochhauser E, Porat E, Shainberg A. Uridine-5'-triphosphate (UTP) maintains cardiac mitochondrial function following chemical and hypoxic stress. J Mol Cell Cardiol 2007; 43:653-62. [PMID: 17880998 DOI: 10.1016/j.yjmcc.2007.07.060] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 07/15/2007] [Accepted: 07/23/2007] [Indexed: 11/22/2022]
Abstract
Previously we found that uridine-5'-triphosphate (UTP) significantly decreased cultured cardiomyocyte death, induced by hypoxia via activating P2Y(2) receptors, reduced infarct size and maintained higher ATP levels in an in vivo model. Mitochondrial contribution to the progression of cardiomyocyte injury in ischemia/hypoxia is well known. However, the protective effects of UTP in cardiac cells with a respiratory chain deficiency are poorly elucidated. The aim of our study was to further define the role of UTP on mitochondrial functional tolerance following chemical and/or ischemic stress in in vivo and in vitro models. Cardiac mitochondrial function was tested 24 h post left anterior descending (LAD) ligation in UTP (0.44 microg/kg)-treated rats. UTP's beneficial effect in LAD-ligated hearts was expressed by improved mitochondrial activity (Complexes I, II and IV). In the in vitro model, cultured cardiomyocytes were pretreated with 50 microM UTP prior to hypoxic and/or chemical stress with rotenone or sodium azide. Pretreatment with UTP maintained increased ATP levels as well as mitochondrial membrane potential and reduced lactate dehydrogenase (LDH) release. A modest reduction (12%) in the mitochondrial membrane potential was demonstrated when the cultured cardiomyocytes were subjected to UTP. This reduction was abolished by the P2Y receptor antagonist, reactive blue 2, but not with 5 hydroxydecanoate, a mitochondrial K(ATP) channel inhibitor, or by BAPTA-AM, the intracellular calcium chelator. We suggest that UTP may act as an uncoupling agent, which exerts a modest mitochondrial depolarization, resulting in a reduction of Ca(2+) uptake, preserving mitochondrial activity, thereby reducing cell damage during hypoxia.
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Affiliation(s)
- Smadar Yitzhaki
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, 52900 Israel
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430
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Shiva S, Sack MN, Greer JJ, Duranski M, Ringwood LA, Burwell L, Wang X, MacArthur PH, Shoja A, Raghavachari N, Calvert JW, Brookes PS, Lefer DJ, Gladwin MT. Nitrite augments tolerance to ischemia/reperfusion injury via the modulation of mitochondrial electron transfer. ACTA ACUST UNITED AC 2007; 204:2089-102. [PMID: 17682069 PMCID: PMC2118713 DOI: 10.1084/jem.20070198] [Citation(s) in RCA: 426] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Nitrite (NO(2)(-)) is an intrinsic signaling molecule that is reduced to NO during ischemia and limits apoptosis and cytotoxicity at reperfusion in the mammalian heart, liver, and brain. Although the mechanism of nitrite-mediated cytoprotection is unknown, NO is a mediator of the ischemic preconditioning cell-survival program. Analogous to the temporally distinct acute and delayed ischemic preconditioning cytoprotective phenotypes, we report that both acute and delayed (24 h before ischemia) exposure to physiological concentrations of nitrite, given both systemically or orally, potently limits cardiac and hepatic reperfusion injury. This cytoprotection is associated with increases in mitochondrial oxidative phosphorylation. Remarkably, isolated mitochondria subjected to 30 min of anoxia followed by reoxygenation were directly protected by nitrite administered both in vitro during anoxia or in vivo 24 h before mitochondrial isolation. Mechanistically, nitrite dose-dependently modifies and inhibits complex I by posttranslational S-nitrosation; this dampens electron transfer and effectively reduces reperfusion reactive oxygen species generation and ameliorates oxidative inactivation of complexes II-IV and aconitase, thus preventing mitochondrial permeability transition pore opening and cytochrome c release. These data suggest that nitrite dynamically modulates mitochondrial resilience to reperfusion injury and may represent an effector of the cell-survival program of ischemic preconditioning and the Mediterranean diet.
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Affiliation(s)
- Sruti Shiva
- Vascular Medicine Branch, National Heart Lung Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
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431
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Abstract
1. Cerebral vessels express oestrogen receptors (ER) in both the smooth muscle and endothelial cell layers of cerebral blood vessels. Levels of ERalpha are higher in female rats chronically exposed to oestrogen, either endogenous or exogenous. 2. Chronic exposure to oestrogen, either endogenous (normally cycling females) or exogenous (ovariectomized with oestrogen replacement), results in cerebral arteries that are more dilated than arteries from ovariectomized counterparts when studied in vitro. This effect is primarily mediated by an increase in the production of vasodilator factors, including nitric oxide (NO) and prostacylin. In contrast, oestrogen appears to suppress the production of endothelial-derived hyperpolarizing factor. Oestrogen treatment increases cerebrovascular levels of endothelial nitric oxide synthase (eNOS), cyclo-oxygenase (COX)-1 and prostacyclin synthase. In addition, via activation of the phosphatidylinositol 3-kinase/Akt pathway, both acute and chronic oestrogen exposure increases eNOS phosphorylation, increasing NO production. 3. Oestrogen receptors have also been localized to cerebrovascular mitochondria and exposure to oestrogen increases the efficiency of energy production while simultaneously reducing mitochondrial production of reactive oxygen species. Oestrogen increases the production of mitochondrial proteins encoded by both mitochondrial and nuclear DNA, including cytochrome c, subunits I and IV of complex IV and Mn-superoxide dismutase. Oestrogen treatment increases the activity of citrate synthase and complex IV and decreases mitochondrial production of H(2)O(2). 4. Oestrogen also has potent anti-inflammatory effects in the cerebral circulation that may have important implications for the incidence and severity of cerebrovascular disease. Administration of lipopolysaccharide or interleukin-1beta to ovariectomized female rats induces cerebrovascular COX-2 and inducible nitric oxide synthase (iNOS) protein expression and increases prostaglandin E(2) expression. Levels of COX-2 and iNOS expression vary with the stage of the oestrous cycle, and the cerebrovascular inflammatory response is suppressed in ovariectomized animals treated with oestrogen. Interleukin-1beta induction of COX-2 protein is prevented by treatment with a nuclear factor (NF)-kappaB inhibitor, and oestrogen treatment reduces cerebrovascular NF-kappaB activity. 5. Cerebrovascular dysfunction and pathology contribute to the pathogenesis of stroke, brain trauma, oedema and dementias, such as Alzheimer's disease. A better understanding of the action of oestrogen on cerebrovascular function holds promise for the development of new therapeutic entities that could be useful in preventing or treating a wide variety of cerebrovascular diseases.
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Affiliation(s)
- Sue P Duckles
- Department of Pharmacology, School of Medicine, University of California, Irvine, California 92697, USA.
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432
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Milner PI, Wilkins RJ, Gibson JS. The role of mitochondrial reactive oxygen species in pH regulation in articular chondrocytes. Osteoarthritis Cartilage 2007; 15:735-42. [PMID: 17306992 DOI: 10.1016/j.joca.2007.01.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Accepted: 01/06/2007] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To examine the effect of O(2) and the role, and source, of reactive oxygen species (ROS) on pH regulation in articular chondrocytes. METHODS Cartilage from equine metacarpo/tarsophalangeal joints was digested (collagenase) to isolate chondrocytes and loaded with 2',7'-bis-2-(carboxyethyl)-5(6)-carboxylfluorescein, a pH-sensitive fluorophore. O(2) tension was maintained using Eschweiler tonometers and a Wosthoff gas mixer. Cells were exposed to agents which alter ROS levels, mitochondrial inhibitors and/or inhibitors of protein phosphorylation. ROS levels were determined by dichlorofluorescein and mitochondrial membrane potential measured using JC-1. RESULTS pH homeostasis was dependent on ROS. Na(+)/H(+) exchanger (NHE) activity was inhibited at low O(2) tension (acid efflux reducing from 2.30+/-0.05 to 1.27+/-0.11mMmin(-1) at 1%). NHE activity correlated with ROS levels (r(2)=0.65). ROS levels were increased by antimycin A (with levels at 1% O(2) tension increasing from 59+/-9% of the value at 20% to 87+/-7%), but reduced by rotenone, myxothiazol and diphenyleneiodonium. Hypoxia induced depolarisation of the mitochondrial membrane potential (with JC-1 red-green fluorescence ratio at 1% O(2) tension decreasing to 40+/-10% of the value at 20%). The response to changes in O(2) and to antimycin A was inhibited by staurosporine, wortmanin and calyculin A. CONCLUSION The fall in ROS levels in hypoxia reduces the ability of articular chondrocytes to regulate pH, inhibiting NHE activity via changes in protein phosphorylation. The site of ROS generation is likely to be mitochondrial electron transport chain complex III. These effects are important to understanding normal chondrocyte function and response to altered O(2) tension.
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Affiliation(s)
- P I Milner
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
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433
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Judge S, Leeuwenburgh C. Cardiac mitochondrial bioenergetics, oxidative stress, and aging. Am J Physiol Cell Physiol 2007; 292:C1983-92. [PMID: 17344313 DOI: 10.1152/ajpcell.00285.2006] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondria have been a central focus of several theories of aging as a result of their critical role in bioenergetics, oxidant production, and regulation of cell death. A decline in cardiac mitochondrial function coupled with the accumulation of oxidative damage to macromolecules may be causal to the decline in cardiac performance with age. In contrast, regular physical activity and lifelong caloric restriction can prevent oxidative stress, delay the onset of morbidity, increase life span, and reduce the risk of developing several pathological conditions. The health benefits of life long exercise and caloric restriction may be, at least partially, due to a reduction in the chronic amount of mitochondrial oxidant production. In addition, the available data suggest that chronic exercise may serve to enhance antioxidant enzyme activities, and augment certain repair/removal pathways, thereby reducing the amount of oxidative tissue damage. However, the characterization of age-related changes to cardiac mitochondria has been complicated by the fact that two distinct populations of mitochondria exist in the myocardium: subsarcolemmal mitochondria and interfibrillar mitochondria. Several studies now suggest the importance of studying both mitochondrial populations when attempting to elucidate the contribution of mitochondrial dysfunction to myocardial aging. The role that mitochondrial dysfunction and oxidative stress play in contributing to cardiac aging will be discussed along with the use of lifelong exercise and calorie restriction as countermeasures to aging.
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Affiliation(s)
- Sharon Judge
- Dept. of Medicine, University of Florida, College of Medicine, Gainesville, FL 32611, USA
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434
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Heinen A, Aldakkak M, Stowe DF, Rhodes SS, Riess ML, Varadarajan SG, Camara AKS. Reverse electron flow-induced ROS production is attenuated by activation of mitochondrial Ca2+-sensitive K+ channels. Am J Physiol Heart Circ Physiol 2007; 293:H1400-7. [PMID: 17513497 DOI: 10.1152/ajpheart.00198.2007] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mitochondria generate reactive oxygen species (ROS) dependent on substrate conditions, O(2) concentration, redox state, and activity of the mitochondrial complexes. It is well known that the FADH(2)-linked substrate succinate induces reverse electron flow to complex I of the electron transport chain and that this process generates superoxide (O(2)(*-)); these effects are blocked by the complex I blocker rotenone. We demonstrated recently that succinate + rotenone-dependent H(2)O(2) production in isolated mitochondria increased mildly on activation of the putative big mitochondrial Ca(2+)-sensitive K(+) channel (mtBK(Ca)) by low concentrations of 1,3-dihydro-1-[2-hydroxy-5-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-2H-benzimidazol-2-one (NS-1619). In the present study we examined effects of NS-1619 on mitochondrial O(2) consumption, membrane potential (DeltaPsi(m)), H(2)O(2) release rates, and redox state in isolated guinea pig heart mitochondria respiring on succinate but without rotenone. NS-1619 (30 microM) increased state 2 and state 4 respiration by 26 +/- 4% and 14 +/- 4%, respectively; this increase was abolished by the BK(Ca) channel blocker paxilline (5 microM). Paxilline alone had no effect on respiration. NS-1619 did not alter DeltaPsi(m) or redox state but decreased H(2)O(2) production by 73% vs. control; this effect was incompletely inhibited by paxilline. We conclude that under substrate conditions that allow reverse electron flow, matrix K(+) influx through mtBK(Ca) channels reduces mitochondrial H(2)O(2) production by accelerating forward electron flow. Our prior study showed that NS-1619 induced an increase in H(2)O(2) production with blocked reverse electron flow. The present results suggest that NS-1619-induced matrix K(+) influx increases forward electron flow despite the high reverse electron flow, and emphasize the importance of substrate conditions on interpretation of effects on mitochondrial bioenergetics.
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Affiliation(s)
- André Heinen
- Anesthesiology Research Laboratories, Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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435
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Nagasaka S, Katoh H, Niu CF, Matsui S, Urushida T, Satoh H, Watanabe Y, Hayashi H. Protein kinase A catalytic subunit alters cardiac mitochondrial redox state and membrane potential via the formation of reactive oxygen species. Circ J 2007; 71:429-36. [PMID: 17322647 DOI: 10.1253/circj.71.429] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The identification of protein kinase A (PKA) anchoring proteins on mitochondria implies a direct effect of PKA on mitochondrial function. However, little is known about the relationship between PKA and mitochondrial metabolism. METHODS AND RESULTS The effects of PKA on the mitochondrial redox state (flavin adenine dinucleotide (FAD)), mitochondrial membrane potential (DeltaPsi(m)) and reactive oxygen species (ROS) production were investigated in saponin-permeabilized rat cardiomyocytes. The PKA catalytic subunit (PKAcat; 50 unit/ml) increased FAD intensities by 56.6+/-7.9% (p<0.01), 2'7'-dichlorofluorescin diacetate (DCF) intensities by 10.5+/-3.3 fold (p<0.01) and depolarized DeltaPsi(m) to 48.1+/-9.5% of the control (p<0.01). Trolox (a ROS scavenger; 100 micromol/L) inhibited PKAcat-induced DeltaPsi(m), FAD and DCF alteration. PKAcat-induced DeltaPsi(m) depolarization was inhibited by an inhibitor of the inner membrane anion channel (IMAC), 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS: 1 micromol/L) but not by an inhibitor of mitochondrial permeability transition pore (mPTP), cyclosporine A (100 nmol/L). CONCLUSIONS PKAcat alters FAD and DeltaPsi(m) via mitochodrial ROS generation, and PKAcat-induced DeltaPsi(m) depolarization was not caused by mPTP but rather by DIDS-sensitive mechanisms, which could be caused by opening of the IMAC. The effects of PKA on mitochondrial function could be related to myocardial function under the condition of extensive beta-adrenergic stimulation.
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Affiliation(s)
- Shiro Nagasaka
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Hamamatsu, Japan
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436
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Schönfeld P, Wojtczak L. Fatty acids decrease mitochondrial generation of reactive oxygen species at the reverse electron transport but increase it at the forward transport. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:1032-40. [PMID: 17588527 DOI: 10.1016/j.bbabio.2007.04.005] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Revised: 04/11/2007] [Accepted: 04/22/2007] [Indexed: 12/16/2022]
Abstract
Long-chain nonesterified ("free") fatty acids (FFA) can affect the mitochondrial generation of reactive oxygen species (ROS) in two ways: (i) by depolarisation of the inner membrane due to the uncoupling effect and (ii) by partly blocking the respiratory chain. In the present work this dual effect was investigated in rat heart and liver mitochondria under conditions of forward and reverse electron transport. Under conditions of the forward electron transport, i.e. with pyruvate plus malate and with succinate (plus rotenone) as respiratory substrates, polyunsaturated fatty acid, arachidonic, and branched-chain saturated fatty acid, phytanic, increased ROS production in parallel with a partial inhibition of the electron transport in the respiratory chain, most likely at the level of complexes I and III. A linear correlation between stimulation of ROS production and inhibition of complex III was found for rat heart mitochondria. This effect on ROS production was further increased in glutathione-depleted mitochondria. Under conditions of the reverse electron transport, i.e. with succinate (without rotenone), unsaturated fatty acids, arachidonic and oleic, straight-chain saturated palmitic acid and branched-chain saturated phytanic acid strongly inhibited ROS production. This inhibition was partly abolished by the blocker of ATP/ADP transfer, carboxyatractyloside, thus indicating that this effect was related to uncoupling (protonophoric) action of fatty acids. It is concluded that in isolated rat heart and liver mitochondria functioning in the forward electron transport mode, unsaturated fatty acids and phytanic acid increase ROS generation by partly inhibiting the electron transport and, most likely, by changing membrane fluidity. Only under conditions of reverse electron transport, fatty acids decrease ROS generation due to their uncoupling action.
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Affiliation(s)
- Peter Schönfeld
- Institut für Biochemie, Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany.
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437
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Isaev NK, Stel'mashuk EV, Zorov DB. Cellular mechanisms of brain hypoglycemia. BIOCHEMISTRY (MOSCOW) 2007; 72:471-8. [PMID: 17573700 DOI: 10.1134/s0006297907050021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Data on intracellular processes induced by a low glucose level in nerve tissue are presented. The involvement of glutamate and adenosine receptors, mitochondria, reactive oxygen species (ROS), and calcium ions in the development of hypoglycemia-induced damage of neurons is considered. Hypoglycemia-induced calcium overload of neuronal mitochondria is suggested to be responsible for the increased ROS production by mitochondria.
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Affiliation(s)
- N K Isaev
- Belozersky Institute of Physico-Nhemical Biology, Lomonosov Moscow State University, Moscow 119992, Russia.
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438
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Capetanaki Y, Bloch RJ, Kouloumenta A, Mavroidis M, Psarras S. Muscle intermediate filaments and their links to membranes and membranous organelles. Exp Cell Res 2007; 313:2063-76. [PMID: 17509566 DOI: 10.1016/j.yexcr.2007.03.033] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 03/20/2007] [Accepted: 03/29/2007] [Indexed: 12/17/2022]
Abstract
Intermediate filaments (IFs) play a key role in the integration of structure and function of striated muscle, primarily by mediating mechanochemical links between the contractile apparatus and mitochondria, myonuclei, the sarcolemma and potentially the vesicle trafficking apparatus. Linkage of all these membranous structures to the contractile apparatus, mainly through the Z-disks, supports the integration and coordination of growth and energy demands of the working myocyte, not only with force transmission, but also with de novo gene expression, energy production and efficient protein and lipid trafficking and targeting. Desmin, the most abundant and intensively studied muscle intermediate filament protein, is linked to proper costamere organization, myoblast and stem cell fusion and differentiation, nuclear shape and positioning, as well as mitochondrial shape, structure, positioning and function. Similar links have been established for lysosomes and lysosome-related organelles, consistent with the presence of widespread links between IFs and membranous structures and the regulation of their fusion, morphology and stabilization necessary for cell survival.
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Affiliation(s)
- Yassemi Capetanaki
- Cell Biology Division, Center of Basic Research, Biomedical Research Foundation Academy of Athens, Soranou Efessiou 4, 12965 Athens, Greece.
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439
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McCully JD, Rousou AJ, Parker RA, Levitsky S. Age- and gender-related differences in mitochondrial oxygen consumption and calcium with cardioplegia and diazoxide. Ann Thorac Surg 2007; 83:1102-9. [PMID: 17307466 PMCID: PMC2673576 DOI: 10.1016/j.athoracsur.2006.10.059] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 10/18/2006] [Accepted: 10/23/2005] [Indexed: 01/25/2023]
Abstract
BACKGROUND We have recently shown that the cardioprotection afforded by cardioplegia is affected by age and gender and is less effective in the aged female rabbit heart compared with the aged male rabbit heart. We hypothesized that these differences were due to age and gender-specific modulation of mitochondrial oxygen consumption and mitochondrial free matrix calcium ([Ca2+](Mito)) content occurring during early reperfusion. METHODS To test this hypothesis, 104 male and female rabbit hearts, mature (15 to 20 weeks) and aged (>32 months), were subjected to Langendorff perfusion. Control hearts were perfused for 75 minutes. Global ischemia hearts were underwent 30 minutes of equilibrium, 30 minutes of global ischemia, and 15 minutes of reperfusion. Cardioplegia (potassium/magnesium) +/- diazoxide was infused 5 minutes before global ischemia. Mitochondria were isolated from left ventricular tissue and used for the measurement of oxygen consumption and [Ca2+](Mito). RESULTS Mitochondrial oxygen consumption was significantly increased in the mature and aged female hearts in all treatment groups (p < 0.001 versus male). Cardioplegia +/- diazoxide modulated mitochondrial oxygen consumption, but these effects were significantly decreased in the aged heart and in the female heart (p < 0.001 each versus male). Cardioplegia (potassium/magnesium) significantly decreased [Ca2+](Mito) (p < 0.001 versus global ischemia) in aged but not mature hearts. The addition of diazoxide to potassium/magnesium significantly decreased [Ca2+](Mito) in mature and aged males (p < 0.001 versus potassium/magnesium) but not in females. CONCLUSIONS These results demonstrate that mitochondrial oxygen consumption and [Ca2+](Mito) are modulated by age and gender and play an important role in the differences observed between mature and aged male and female response to global ischemia and the cardioprotection afforded by cardioplegia +/- diazoxide.
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Affiliation(s)
- James D McCully
- Division of Cardiothoracic Surgery, Beth Israel Deaconess Medical Center, Harvard Institutes of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA.
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440
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Pepe S, Marasco SF, Haas SJ, Sheeran FL, Krum H, Rosenfeldt FL. Coenzyme Q10 in cardiovascular disease. Mitochondrion 2007; 7 Suppl:S154-67. [PMID: 17485243 DOI: 10.1016/j.mito.2007.02.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 02/06/2007] [Accepted: 02/10/2007] [Indexed: 12/26/2022]
Abstract
In this review we summarise the current state of knowledge of the therapeutic efficacy and mechanisms of action of CoQ(10) in cardiovascular disease. Our conclusions are: 1. There is promising evidence of a beneficial effect of CoQ(10) when given alone or in addition to standard therapies in hypertension and in heart failure, but less extensive evidence in ischemic heart disease. 2. Large scale multi-centre prospective randomised trials are indicated in all these areas but there are difficulties in funding such trials. 3. Presently, due to the notable absence of clinically significant side effects and likely therapeutic benefit, CoQ(10) can be considered a safe adjunct to standard therapies in cardiovascular disease.
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Affiliation(s)
- Salvatore Pepe
- CJOB Department of Cardiothoracic Surgery, Alfred Hospital, Melbourne, Australia
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441
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Brevig T, Røhrmann JH, Riemann H. Oxygen reduces accumulation of type IV collagen in endothelial cell subcellular matrix via oxidative stress. Artif Organs 2007; 30:915-21. [PMID: 17181832 DOI: 10.1111/j.1525-1594.2006.00324.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Anchorage-dependent cells in culture attach initially to proteins adsorbed to the culture substrate from the medium, and produce and deposit a subcellular matrix during the course of the cultivation. The aim of this study was to determine whether the concentration of O(2) in the culture atmosphere affects the accumulation of type IV collagen and laminin under human endothelial-cell monolayers. Enzyme-linked immunoassays on decellularized polystyrene substrates showed less type IV collagen, but not less laminin, under cells incubated in the standard atmosphere (5% CO(2) in air, i.e., approximately 20% O(2)) compared to an atmosphere of 5% O(2) and 5% CO(2) in N(2). Type IV collagen accumulation was inhibited via oxidative stress, because the inhibitory effect of 20% O(2) was antagonized by antioxidant ascorbic acid, and mimicked by prooxidant pyrogallol and exogenous H(2)O(2). Measurements of endogenous H(2)O(2) accumulation demonstrated that endothelial cells partially adapt to the high O(2) concentration. These results may have implications in endothelium modeling in vitro and in engineering of endothelial cell sheets and endothelialized vascular grafts.
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Affiliation(s)
- Thomas Brevig
- Research & Development, Nunc A/S, Roskilde, Denmark.
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442
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Qi D, Rodrigues B. Glucocorticoids produce whole body insulin resistance with changes in cardiac metabolism. Am J Physiol Endocrinol Metab 2007; 292:E654-67. [PMID: 17077342 DOI: 10.1152/ajpendo.00453.2006] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Insulin resistance is viewed as an insufficiency in insulin action, with glucocorticoids being recognized to play a key role in its pathogenesis. With insulin resistance, metabolism in multiple organ systems such as skeletal muscle, liver, and adipose tissue is altered. These metabolic alterations are widely believed to be important factors in the morbidity and mortality of cardiovascular disease. More importantly, clinical and experimental studies have established that metabolic abnormalities in the heart per se also play a crucial role in the development of heart failure. Following glucocorticoids, glucose utilization is compromised in the heart. This attenuated glucose metabolism is associated with altered fatty acid supply, composition, and utilization. In the heart, elevated fatty acid use has been implicated in a number of metabolic, morphological, and mechanical changes and, more recently, in "lipotoxicity". In the present article, we review the action of glucocorticoids, their role in insulin resistance, and their influence in modulating peripheral and cardiac metabolism and heart disease.
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Affiliation(s)
- Dake Qi
- Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, The University of British Columbia, 2146 East Mall, Vancouver, BC, Canada V6T 1Z3
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443
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Rennison JH, McElfresh TA, Okere IC, Vazquez EJ, Patel HV, Foster AB, Patel KK, Chen Q, Hoit BD, Tserng KY, Hassan MO, Hoppel CL, Chandler MP. High-fat diet postinfarction enhances mitochondrial function and does not exacerbate left ventricular dysfunction. Am J Physiol Heart Circ Physiol 2007; 292:H1498-506. [PMID: 17114240 DOI: 10.1152/ajpheart.01021.2006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Lipid accumulation in nonadipose tissue due to enhanced circulating fatty acids may play a role in the pathophysiology of heart failure, obesity, and diabetes. Accumulation of myocardial lipids and related intermediates, e.g., ceramide, is associated with decreased contractile function, mitochondrial oxidative phosphorylation, and electron transport chain (ETC) complex activities. We tested the hypothesis that the progression of heart failure would be exacerbated by elevated myocardial lipids and an associated ceramide-induced inhibition of mitochondrial oxidative phosphorylation and ETC complex activities. Heart failure (HF) was induced by coronary artery ligation. Rats were then randomly assigned to either a normal (10% kcal from fat; HF, n = 8) or high saturated fat diet (60% kcal from saturated fat; HF + Sat, n = 7). Sham-operated animals (sham; n = 8) were fed a normal diet. Eight weeks postligation, left ventricular (LV) function was assessed by echocardiography and catheterization. Subsarcolemmal and interfibrillar mitochondria were isolated from the LV. Heart failure resulted in impaired LV contractile function [decreased percent fractional shortening and peak rate of LV pressure rise and fall (±dP/d t)] and remodeling (increased end-diastolic and end-systolic dimensions) in HF compared with sham. No further progression of LV dysfunction was evident in HF + Sat. Mitochondrial state 3 respiration was increased in HF + Sat compared with HF despite elevated myocardial ceramide. Activities of ETC complexes II and IV were elevated in HF + Sat compared with HF and sham. High saturated fat feeding following coronary artery ligation was associated with increased oxidative phosphorylation and ETC complex activities and did not adversely affect LV contractile function or remodeling, despite elevations in myocardial ceramide.
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Affiliation(s)
- Julie H Rennison
- Dept of Physiology and Biophysics, School of Medicine E558, Case Western Reserve Univ, Cleveland, OH 44106-4970, USA
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444
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Starnes JW, Barnes BD, Olsen ME. Exercise training decreases rat heart mitochondria free radical generation but does not prevent Ca2+-induced dysfunction. J Appl Physiol (1985) 2007; 102:1793-8. [PMID: 17303708 DOI: 10.1152/japplphysiol.00849.2006] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Exercise provides cardioprotection against ischemia-reperfusion injury, a process involving mitochondrial reactive oxygen species (ROS) generation and calcium overload. This study tested the hypotheses that isolated mitochondria from hearts of endurance-trained rats have decreased ROS production and improved tolerance against Ca(2+)-induced dysfunction. Male Fischer 344 rats were either sedentary (Sed, n = 8) or endurance exercise trained (ET, n = 11) by running on a treadmill for 16 wk (5 days/wk, 60 min/day, 25 m/min, 6 degrees grade). Mitochondrial oxidative phosphorylation measures were determined with glutamate-malate or succinate as substrates, and H(2)O(2) production and permeability transition pore (PTP) opening were determined with succinate. All assays were carried out in the absence and presence of calcium. In response to 25 and 50 microM CaCl(2), Sed and ET displayed similar decreases in state 3 respiration, respiratory control ratio, and ADP:O ratio. Ca(2+)-induced PTP opening was also similar. However, H(2)O(2) production by ET was lower than Sed (P < 0.05) in the absence of calcium (323 +/- 12 vs. 362 +/- 11 pmol.min(-1).mg protein(-1)) and the presence of 50 microM CaCl(2) (154 +/- 3 vs. 197 +/- 7 pmol.min(-1).mg protein(-1)). Rotenone, which blocks electron flow from succinate to complex 1, reduced H(2)O(2) production and eliminated differences between ET and Sed. Mitochondrial superoxide dismutase and glutathione peroxidase were not affected by exercise. Catalase activity was extremely low but increased 49% in ET (P < 0.05). In conclusion, exercise reduces ROS production in myocardial mitochondria through adaptations specific to complex 1 but does not improve mitochondrial tolerance to calcium overload.
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Affiliation(s)
- Joseph W Starnes
- Dept. of Kinesiology and Health Education, The University of Texas at Austin, Austin, TX 78712-0360, USA.
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445
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Spear JF, Prabu SK, Galati D, Raza H, Anandatheerthavarada HK, Avadhani NG. beta1-Adrenoreceptor activation contributes to ischemia-reperfusion damage as well as playing a role in ischemic preconditioning. Am J Physiol Heart Circ Physiol 2007; 292:H2459-66. [PMID: 17237252 DOI: 10.1152/ajpheart.00459.2006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein kinase A (PKA) activation has been implicated in early-phase ischemic preconditioning. We recently found that during ischemia PKA activation causes inactivation of cytochrome-c oxidase (CcO) and contributes to myocardial damage due to ischemia-reperfusion. It may be that beta-adrenergic stimulation during ischemia via endogenous catecholamine release activates PKA. Thus beta-adrenergic stimulation may mediate both myocardial protection and damage during ischemia. The present studies were designed to determine the role of the beta(1)-adrenergic receptor (beta(1)-AR) in myocardial ischemic damage and ischemic preconditioning. Langendorff-perfused rabbit hearts underwent 30-min ischemia by anterior coronary artery ligation followed by 2-h reperfusion. Occlusion-reperfusion damage was evaluated by delineating the nonperfused volume of myocardium at risk and volume of myocardial necrosis after 2-h reperfusion. In some hearts ischemic preconditioning was accomplished by two 5-min episodes of global low-flow ischemia separated by 10 min before coronary occlusion-reperfusion. Orthogonal electrocardiograms were recorded, and coronary flow was monitored by a drip count. Three hearts from each experimental group were used to determine mitochondrial CcO and aconitase activities. Two-hour reperfusion after occlusion caused an additional decrease in CcO activity vs. that after 30-min occlusion alone. Blocking the beta(1)-AR during occlusion-reperfusion reversed CcO activity depression and preserved myocardium at risk for necrosis. Similarly, mitochondrial aconitase activity exhibited a parallel response after occlusion-reperfusion as well as for the other interventions. Furthermore, classic ischemic preconditioning had no effect on CcO depression. However, blocking the beta(1)-AR during preconditioning eliminated the cardioprotection. If the beta(1)-AR was blocked after preconditioning, the myocardium was preserved. Interestingly, in both of the latter cases the depression in CcO activity was reversed. Thus the beta(1)-AR plays a dual role in myocardial ischemic damage. Our findings may lead to therapeutic strategies for preserving myocardium at risk for infarction, especially in coronary reperfusion intervention.
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Affiliation(s)
- Joseph F Spear
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia PA 19104-6046, USA.
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446
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Makazan Z, Saini HK, Dhalla NS. Role of oxidative stress in alterations of mitochondrial function in ischemic-reperfused hearts. Am J Physiol Heart Circ Physiol 2006; 292:H1986-94. [PMID: 17172267 DOI: 10.1152/ajpheart.01214.2006] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
To study the mechanisms of mitochondrial dysfunction due to ischemia-reperfusion (I/R) injury, rat hearts were subjected to 20 or 30 min of global ischemia followed by 30 min of reperfusion. After recording both left ventricular developed pressure (LVDP) and end-diastolic pressure (LVEDP) to monitor the status of cardiac performance, mitochondria from these hearts were isolated to determine respiratory and oxidative phosphorylation activities. Although hearts subjected to 20 min of ischemia failed to generate LVDP and showed a marked increase in LVEDP, no changes in mitochondrial respiration and phosphorylation were observed. Reperfusion of 20-min ischemic hearts depressed mitochondrial function significantly but recovered LVDP completely and lowered the elevated LVEDP. On the other hand, depressed LVDP and elevated LVEDP in 30-min ischemic hearts were associated with depressions in both mitochondrial respiration and oxidative phosphorylation. Reperfusion of 30-min ischemic hearts elevated LVEDP, attenuated LVDP, and decreased mitochondrial state 3 and uncoupled respiration, respiratory control index, ADP-to-O ratio, as well as oxidative phosphorylation rate. Alterations of cardiac performance and mitochondrial function in I/R hearts were attenuated or prevented by pretreatment with oxyradical scavenging mixture (superoxide dismutase and catalase) or antioxidants [N-acetyl-L-cysteine or N-(2-mercaptopropionyl)-glycine]. Furthermore, alterations in cardiac performance and mitochondrial function due to I/R were simulated by an oxyradical-generating system (xanthine plus xanthine oxidase) and an oxidant (H(2)O(2)) either upon perfusing the heart or upon incubation with mitochondria. These results support the view that oxidative stress plays an important role in inducing changes in cardiac performance and mitochondrial function due to I/R.
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Affiliation(s)
- Zhanna Makazan
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, and Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
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447
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Lesnefsky EJ, Hoppel CL. Oxidative phosphorylation and aging. Ageing Res Rev 2006; 5:402-33. [PMID: 16831573 DOI: 10.1016/j.arr.2006.04.001] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Revised: 04/01/2006] [Accepted: 04/04/2006] [Indexed: 10/24/2022]
Abstract
This review addresses the data that support the presence and contribution of decreased mitochondrial oxidative phosphorylation during aging to impaired cellular metabolism. Aging impairs substrate oxidation, decreases cellular energy production and increases the production of reactive intermediates that are toxic to the cell. First, the basic principles of mitochondrial oxidative physiology are briefly reviewed. Second, the focus on the relationship of altered mitochondrial respiration to the increased production of reactive oxygen species that are employed by the "rate of living" and the "uncoupling to survive" theories of aging are discussed. Third, the impairment of function of respiration in aging is reviewed using an organ-based approach in mammalian systems. Fourth, the current state of knowledge regarding aging-induced alterations in the composition and function of key mitochondrial constituents is addressed. Model organisms, including C. elegans and D. melanogaster are included where pertinent. Fifth, these defects are related to knowledge regarding the production of reactive oxygen species from specific sites of the electron transport chain.
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Affiliation(s)
- Edward J Lesnefsky
- Department of Medicine, Division of Cardiology, Case Western Reserve University, Cleveland, OH, USA
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448
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de J García-Rivas G, Carvajal K, Correa F, Zazueta C. Ru360, a specific mitochondrial calcium uptake inhibitor, improves cardiac post-ischaemic functional recovery in rats in vivo. Br J Pharmacol 2006; 149:829-37. [PMID: 17031386 PMCID: PMC2014682 DOI: 10.1038/sj.bjp.0706932] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE The mitochondrial permeability transition pore (mPTP), an energy-dissipating channel activated by calcium, contributes to reperfusion damage by depolarizing the mitochondrial inner membrane potential. As mitochondrial Ca(2+) overload is a main inductor of mPTP opening, we examined the effect of Ru(360), a selective inhibitor of the mitochondrial calcium uptake system against myocardial damage induced by reperfusion in a rat model. EXPERIMENTAL APPROACH Myocardial reperfusion injury was induced by a 5-min occlusion of the left anterior descending coronary artery, followed by a 5-min reperfusion in anaesthetized open-chest rats. We measured reperfusion-induced arrhythmias and functions indicative of unimpaired mitochondrial integrity to evaluate the effect of Ru(360) treatment. KEY RESULTS Reperfusion elicited a high incidence of arrhythmias, haemodynamic dysfunction and loss of mitochondrial integrity. A bolus intravenous injection of Ru(360) (15-50 nmol kg(-1)), given 30-min before ischaemia, significantly improved the above mentioned variables in the ischaemic/reperfused myocardium. Calcium uptake in isolated mitochondria from Ru(360)-treated ventricles was partially diminished, suggesting an interaction of this compound with the calcium uniporter. CONCLUSIONS AND IMPLICATIONS We showed that Ru(360) treatment abolishes the incidence of arrhythmias and haemodynamic dysfunction elicited by reperfusion in a whole rat model. Ru(360) administration partially inhibits calcium uptake, preventing mitochondria from depolarization by the opening of the mPTP. We conclude that myocardial damage could be a consequence of failure of the mitochondrial network to maintain the membrane potential at reperfusion. Hence, it is plausible that Ru(360) could be used in reperfusion therapy to prevent the occurrence of arrhythmia.
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Affiliation(s)
- G de J García-Rivas
- Departamento de Bioquímica. Instituto Nacional de Cardiología ‘Ignacio Chávez' México DF, México
| | - K Carvajal
- Departamento de Bioquímica. Instituto Nacional de Cardiología ‘Ignacio Chávez' México DF, México
| | - F Correa
- Departamento de Bioquímica. Instituto Nacional de Cardiología ‘Ignacio Chávez' México DF, México
| | - C Zazueta
- Departamento de Bioquímica. Instituto Nacional de Cardiología ‘Ignacio Chávez' México DF, México
- Author for correspondence:
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449
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Chen Q, Moghaddas S, Hoppel CL, Lesnefsky EJ. Reversible blockade of electron transport during ischemia protects mitochondria and decreases myocardial injury following reperfusion. J Pharmacol Exp Ther 2006; 319:1405-12. [PMID: 16990510 DOI: 10.1124/jpet.106.110262] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Cardiac mitochondria sustain damage during ischemia and reperfusion, contributing to cell death. The reversible blockade of electron transport during ischemia with amobarbital, an inhibitor at the rotenone site of complex I, protects mitochondria against ischemic damage. Amobarbital treatment immediately before ischemia was used to test the hypothesis that damage to mitochondrial respiration occurs mainly during ischemia and that protection of mitochondria during ischemia leads to decreased cardiac injury with reperfusion. Langendorff-perfused Fischer-344 rat hearts were treated with amobarbital (2.5 mM) or vehicle for 1 min immediately before 25 min of global ischemia. Both groups were reperfused for 30 min without additional treatment. Subsarcolemmal (SSM) and interfibrillar (IFM) populations of mitochondria were isolated after reperfusion. Ischemia and reperfusion decreased state 3 and increased state 4 respiration rate in both SSM and IFM. Amobarbital treatment protected oxidative phosphorylation measured following reperfusion and improved the coupling of respiration. Cytochrome c content measured in SSM and IFM following reperfusion decreased in untreated, but not in amobarbital-treated, hearts. H(2)O(2) release from SSM and IFM isolated from amobarbital-treated hearts during reperfusion was markedly decreased. Amobarbital treatment before ischemia improved recovery of contractile function (percentage of preischemic developed pressure: untreated 51 +/- 4%, n = 12; amobarbital 70 +/- 4%, n = 11, p < 0.01) and substantially reduced infarct size (untreated 32 +/- 2%, n = 7; amobarbital 13 +/- 2%, n = 7, p < 0.01). Thus, mitochondrial damage occurs mainly during ischemia rather than during reperfusion. Reperfusion in the setting of preserved mitochondrial respiratory function attenuates the mitochondrial release of reactive oxygen species, enhances contractile recovery, and decreases myocardial infarct size.
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Affiliation(s)
- Qun Chen
- Department of Medicine, Division of Cardiology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
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450
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Chen Q, Camara AKS, Stowe DF, Hoppel CL, Lesnefsky EJ. Modulation of electron transport protects cardiac mitochondria and decreases myocardial injury during ischemia and reperfusion. Am J Physiol Cell Physiol 2006; 292:C137-47. [PMID: 16971498 DOI: 10.1152/ajpcell.00270.2006] [Citation(s) in RCA: 205] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mitochondria are increasingly recognized as lynchpins in the evolution of cardiac injury during ischemia and reperfusion. This review addresses the emerging concept that modulation of mitochondrial respiration during and immediately following an episode of ischemia can attenuate the extent of myocardial injury. The blockade of electron transport and the partial uncoupling of respiration are two mechanisms whereby manipulation of mitochondrial metabolism during ischemia decreases cardiac injury. Although protection by inhibition of electron transport or uncoupling of respiration initially appears to be counterintuitive, the continuation of mitochondrial oxidative phosphorylation in the pathological milieu of ischemia generates reactive oxygen species, mitochondrial calcium overload, and the release of cytochrome c. The initial target of these deleterious mitochondrial-driven processes is the mitochondria themselves. Consequences to the cardiomyocyte, in turn, include oxidative damage, the onset of mitochondrial permeability transition, and activation of apoptotic cascades, all favoring cardiomyocyte death. Ischemia-induced mitochondrial damage carried forward into reperfusion further amplifies these mechanisms of mitochondrial-driven myocyte injury. Interruption of mitochondrial respiration during early reperfusion by pharmacologic blockade of electron transport or even recurrent hypoxia or brief ischemia paradoxically decreases cardiac injury. It increasingly appears that the cardioprotective paradigms of ischemic preconditioning and postconditioning utilize modulation of mitochondrial oxidative metabolism as a key effector mechanism. The initially counterintuitive approach to inhibit mitochondrial respiration provides a new cardioprotective paradigm to decrease cellular injury during both ischemia and reperfusion.
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Affiliation(s)
- Qun Chen
- Cardiology Section, Medical Service 111(W), Louis Stokes VA Medical Center, 10701 East Blvd., Cleveland, OH 44106, USA
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