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Chen Q, Kovilakath A, Allegood J, Thompson J, Hu Y, Cowart LA, Lesnefsky EJ. Endoplasmic reticulum stress and mitochondrial dysfunction during aging: Role of sphingolipids. Biochim Biophys Acta Mol Cell Biol Lipids 2023; 1868:159366. [PMID: 37473835 PMCID: PMC11154090 DOI: 10.1016/j.bbalip.2023.159366] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 06/24/2023] [Accepted: 07/11/2023] [Indexed: 07/22/2023]
Abstract
The endoplasmic reticulum (ER) plays a key role in the regulation of protein folding, lipid synthesis, calcium homeostasis, and serves as a primary site of sphingolipid biosynthesis. ER stress (ER dysfunction) participates in the development of mitochondrial dysfunction during aging. Mitochondria are in close contact with the ER through shared mitochondria associated membranes (MAM). Alteration of sphingolipids contributes to mitochondria-driven cell injury. Cardiolipin is a phospholipid that is critical to maintain enzyme activity in the electron transport chain. The aim of the current study was to characterize the changes in sphingolipids and cardiolipin in ER, MAM, and mitochondria during the progression of aging in young (3 mo.), middle (18 mo.), and aged (24 mo.) C57Bl/6 mouse hearts. ER stress increased in hearts from 18 mo. mice and mice exhibited mitochondrial dysfunction by 24 mo. Hearts were pooled to isolate ER, MAM, and subsarcolemmal mitochondria (SSM). LC-MS/MS quantification of lipid content showed that aging increased ceramide content in ER and MAM. In addition, the contents of sphingomyelin and monohexosylceramides are also increased in the ER from aged mice. Aging increased the total cardiolipin content in the ER. Aging did not alter the total cardiolipin content in mitochondria or MAM yet altered the composition of cardiolipin with aging in line with increased oxidative stress compared to young mice. These results indicate that alteration of sphingolipids can contribute to the ER stress and mitochondrial dysfunction that occurs during aging.
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Affiliation(s)
- Qun Chen
- Department of Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA 23298, United States of America
| | - Anna Kovilakath
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, United States of America
| | - Jeremy Allegood
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, United States of America
| | - Jeremy Thompson
- Department of Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA 23298, United States of America
| | - Ying Hu
- Department of Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA 23298, United States of America
| | - L Ashley Cowart
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, United States of America; Richmond Department of Veterans Affairs Medical Center, Richmond, VA 23249, United States of America
| | - Edward J Lesnefsky
- Department of Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA 23298, United States of America; Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, United States of America; Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA 23298, United States of America; Richmond Department of Veterans Affairs Medical Center, Richmond, VA 23249, United States of America.
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2
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Shilovsky GA, Putyatina TS, Ashapkin VV, Yamskova OV, Lyubetsky VA, Sorokina EV, Shram SI, Markov AV, Vyssokikh MY. Biological Diversity and Remodeling of Cardiolipin in Oxidative Stress and Age-Related Pathologies. BIOCHEMISTRY (MOSCOW) 2020; 84:1469-1483. [PMID: 31870251 DOI: 10.1134/s000629791912006x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Age-related dysfunctions are accompanied by impairments in the mitochondrial morphology, activity of signaling pathway, and protein interactions. Cardiolipin is one of the most important phospholipids that maintains the curvature of the cristae and facilitates assembly and interaction of complexes and supercomplexes of the mitochondrial respiratory chain. The fatty acid composition of cardiolipin influences the biophysical properties of the membrane and, therefore, is crucial for the mitochondrial bioenergetics. The presence of unsaturated fatty acids in cardiolipin is the reason of its susceptibility to oxidative damage. Damaged cardiolipin undergoes remodeling by phospholipases, acyltransferases, and transacylases, creating a highly specific fatty acyl profile for each tissue. In this review, we discuss the variability of cardiolipin fatty acid composition in various species and different tissues of the same species, both in the norm and at various pathologies (e.g., age-related diseases, oxidative and traumatic stresses, knockouts/knockdowns of enzymes of the cardiolipin synthesis pathway). Progressive pathologies, including age-related ones, are accompanied by cardiolipin depletion and decrease in the efficiency of its remodeling, as well as the activation of an alternative way of pathological remodeling, which causes replacement of cardiolipin fatty acids with polyunsaturated ones (e.g., arachidonic or docosahexaenoic acids). Drugs or special diet can contribute to the partial restoration of the cardiolipin acyl profile to the one rich in fatty acids characteristic of an intact organ or tissue, thereby correcting the consequences of pathological or insufficient cardiolipin remodeling. In this regard, an urgent task of biomedicine is to study the mechanism of action of mitochondria-targeted antioxidants effective in the treatment of age-related pathologies and capable of accumulating not only in vitro, but also in vivo in the cardiolipin-enriched membrane fragments.
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Affiliation(s)
- G A Shilovsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia. .,Lomonosov Moscow State University, Faculty of Biology, Moscow, 119234, Russia.,Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, 127051, Russia
| | - T S Putyatina
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119234, Russia
| | - V V Ashapkin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - O V Yamskova
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, 119991, Russia
| | - V A Lyubetsky
- Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, 127051, Russia
| | - E V Sorokina
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119234, Russia
| | - S I Shram
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, 123182, Russia
| | - A V Markov
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119234, Russia
| | - M Y Vyssokikh
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
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3
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Garvin AM, Aurigemma NC, Hackenberger JL, Korzick DH. Age and ischemia differentially impact mitochondrial ultrastructure and function in a novel model of age-associated estrogen deficiency in the female rat heart. Pflugers Arch 2017; 469:1591-1602. [PMID: 28776263 DOI: 10.1007/s00424-017-2034-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 07/10/2017] [Accepted: 07/11/2017] [Indexed: 12/19/2022]
Abstract
Altered mitochondrial respiration, morphology, and quality control collectively contribute to mitochondrial dysfunction in the aged heart. Because myocardial infarction remains the leading cause of death in aged women, the present study utilized a novel rodent model to recapitulate human menopause to interrogate the combination of age and estrogen deficiency on mitochondrial ultrastructure and function with cardiac ischemia/reperfusion (I/R) injury. Female F344 rats were ovariectomized (OVX) at 15 months and studied at 24 months (MO OVX; n = 40) vs adult ovary intact (6 months; n = 41). Temporal declines in estrogen concomitant with increased visceral adipose tissue were observed in MO OVX vs adult. Following in vivo coronary artery ligation or sham surgery, state 3 mitochondrial respiration was selectively reduced by age in subsarcolemmal mitochondria (SSM) and by I/R in interfibrillar mitochondria (IFM); left ventricular maximum dP/dt was reduced in MO OVX (p < 0.05). Elevated cyclophilin D and exacerbated I/R-induced mitochondrial acetylation in MO OVX suggest permeability transition pore involvement and reduced protection vs adult (p < 0.05). Mitochondrial morphology by TEM revealed an altered time course of autophagy coordinate with attenuated Drp1 and LC3BII protein levels with age-associated estrogen loss (p < 0.05). Here, reductions in both SSM and IFM function may play an additive role in enhanced susceptibility to regional I/R injury in aged estrogen-deficient female hearts. Moreover, novel insight into altered cardiac mitochondrial quality control garnered here begins to unravel the potentially important regulatory role of mitochondrial dynamics on sustaining respiratory function in the aged female heart.
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Affiliation(s)
- Alexandra M Garvin
- Intercollege Graduate Degree Program in Physiology, The Pennsylvania State University, 106 Noll Laboratory, University Park, PA, 16802, USA
| | - Nicole C Aurigemma
- Intercollege Graduate Degree Program in Physiology, The Pennsylvania State University, 106 Noll Laboratory, University Park, PA, 16802, USA
| | - Jenna L Hackenberger
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Donna H Korzick
- Intercollege Graduate Degree Program in Physiology, The Pennsylvania State University, 106 Noll Laboratory, University Park, PA, 16802, USA. .,Department of Kinesiology, The Pennsylvania State University, University Park, PA, 16802, USA.
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4
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Lesnefsky EJ, Chen Q, Hoppel CL. Mitochondrial Metabolism in Aging Heart. Circ Res 2017; 118:1593-611. [PMID: 27174952 DOI: 10.1161/circresaha.116.307505] [Citation(s) in RCA: 214] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/05/2016] [Indexed: 02/07/2023]
Abstract
Altered mitochondrial metabolism is the underlying basis for the increased sensitivity in the aged heart to stress. The aged heart exhibits impaired metabolic flexibility, with a decreased capacity to oxidize fatty acids and enhanced dependence on glucose metabolism. Aging impairs mitochondrial oxidative phosphorylation, with a greater role played by the mitochondria located between the myofibrils, the interfibrillar mitochondria. With aging, there is a decrease in activity of complexes III and IV, which account for the decrease in respiration. Furthermore, aging decreases mitochondrial content among the myofibrils. The end result is that in the interfibrillar area, there is ≈50% decrease in mitochondrial function, affecting all substrates. The defective mitochondria persist in the aged heart, leading to enhanced oxidant production and oxidative injury and the activation of oxidant signaling for cell death. Aging defects in mitochondria represent new therapeutic targets, whether by manipulation of the mitochondrial proteome, modulation of electron transport, activation of biogenesis or mitophagy, or the regulation of mitochondrial fission and fusion. These mechanisms provide new ways to attenuate cardiac disease in elders by preemptive treatment of age-related defects, in contrast to the treatment of disease-induced dysfunction.
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Affiliation(s)
- Edward J Lesnefsky
- From the Division of Cardiology, Department of Medicine, Pauley Heart Center (E.J.L, Q.C.), Departments of Biochemistry and Molecular Biology and Physiology and Biophsyics (E.J.L.), Virginia Commonwealth University, Richmond, VA (E.J.L., Q.C.); Medical Service, McGuire Veterans Affairs Medical Center, Richmond, VA (E.J.L.); and Departments of Pharmacology (C.L.H.) and Medicine (E.J.L., C.L.H.), Center for Mitochondrial Disease (C.L.H.), Case Western Reserve University, School of Medicine, Cleveland, OH
| | - Qun Chen
- From the Division of Cardiology, Department of Medicine, Pauley Heart Center (E.J.L, Q.C.), Departments of Biochemistry and Molecular Biology and Physiology and Biophsyics (E.J.L.), Virginia Commonwealth University, Richmond, VA (E.J.L., Q.C.); Medical Service, McGuire Veterans Affairs Medical Center, Richmond, VA (E.J.L.); and Departments of Pharmacology (C.L.H.) and Medicine (E.J.L., C.L.H.), Center for Mitochondrial Disease (C.L.H.), Case Western Reserve University, School of Medicine, Cleveland, OH
| | - Charles L Hoppel
- From the Division of Cardiology, Department of Medicine, Pauley Heart Center (E.J.L, Q.C.), Departments of Biochemistry and Molecular Biology and Physiology and Biophsyics (E.J.L.), Virginia Commonwealth University, Richmond, VA (E.J.L., Q.C.); Medical Service, McGuire Veterans Affairs Medical Center, Richmond, VA (E.J.L.); and Departments of Pharmacology (C.L.H.) and Medicine (E.J.L., C.L.H.), Center for Mitochondrial Disease (C.L.H.), Case Western Reserve University, School of Medicine, Cleveland, OH.
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5
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Mitochondrial Dysfunction in Cardiovascular Aging. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:451-464. [PMID: 28551802 DOI: 10.1007/978-3-319-55330-6_24] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mitochondria are the prime source of ATP in cardiomyocytes. Impairment of mitochondrial metabolism results in damage to existing proteins and DNA. Such deleterious effects are part and parcel of the aging process, reducing the ability of cardiomyocytes to counter stress, such as myocardial infarction and consequent reperfusion. In such conditions, mitochondria in the heart of aged individuals exhibit decreased oxidative phosphorylation, decreased ATP production, and increased net reactive oxygen species production; all of these effects are independent of the decrease in number of mitochondria that occurs in these situations. Rather than being associated with the mitochondrial population in toto, these defects are almost exclusively confined to those organelles positioned between myofibrils (interfibrillar mitochondria). It is in complex III and IV where these dysfunctional aspects are manifested. In an apparent effort to correct mitochondrial metabolic defects, affected organelles are to some extent eliminated by mitophagy; at the same time, new, unaffected organelles are generated by fission of mitochondria. Because these cardiac health issues are localized to specific mitochondria, these organelles offer potential targets for therapeutic approaches that could favorably affect the aging process in heart.
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6
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Drosatos K. Fatty old hearts: role of cardiac lipotoxicity in age-related cardiomyopathy. PATHOBIOLOGY OF AGING & AGE RELATED DISEASES 2016; 6:32221. [PMID: 27558317 PMCID: PMC4996860 DOI: 10.3402/pba.v6.32221] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/29/2016] [Accepted: 07/29/2016] [Indexed: 12/11/2022]
Abstract
Age-related cardiomyopathy accounts for a significant part of heart failure cases. Imbalance of the energetic equilibrium of the heart along with mitochondrial dysfunction and impaired β-adrenergic receptor signaling contributes in the aggravation of cardiac function in the elderly. In this review article, studies that correlate cardiac aging with lipotoxicity are summarized. The involvement of inhibition of peroxisome proliferator-activated receptor-α, β-adrenergic receptor desensitization, and mitochondrial dysfunction as underlying mechanisms for the lipid-driven age-related cardiomyopathy are presented with the aim to indicate potential therapeutic targets for cardiac aging.
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Affiliation(s)
- Konstantinos Drosatos
- Metabolic Biology Laboratory, Department of Pharmacology, Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA;
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Acquired deficiency of tafazzin in the adult heart: Impact on mitochondrial function and response to cardiac injury. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1861:294-300. [PMID: 26692032 DOI: 10.1016/j.bbalip.2015.12.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 11/11/2015] [Accepted: 12/11/2015] [Indexed: 12/22/2022]
Abstract
The content and composition of cardiolipin (CL) is critical for preservation of mitochondrial oxidative phosphorylation (OXPHOS) and inner membrane integrity. Tafazzin (Taz) is an enzyme responsible for remodeling of immature CL containing mixed acyl groups into the mature tetralinoleyl form (C18:2)4-CL. We hypothesized that acquired defects in Taz in the mature heart would impact remodeling of CL and augment cardiac injury. The role of acquired Taz deficiency was studied using the inducible Taz knockdown (TazKD) mouse. Taz-specific shRNA is induced by doxycycline (DOX). One day of DOX intake decreased Taz mRNA in the heart to 20% vs. DOX-treated WT. Knockdown was initiated at an adult age and was stable during long term feeding. CL phenotype was assessed by (C18:2)4-CL content and was reduced 40% vs. WT at two months of DOX. TazKD showed increased production of reactive oxygen species and increased susceptibility to permeability transition pore opening at baseline. However, OXPHOS measured using the rate of oxygen consumption was unchanged in the setting of acquired Taz deficiency. Infarct size, measured in isolated buffer-perfused Langendorff hearts following 25min. Stop flow ischemia and 60min. Reperfusion was not altered in TazKD hearts. Thus, impaired Taz-function with onset at adult age does not enhance susceptibility to ischemia-reperfusion injury.
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8
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Tocchi A, Quarles EK, Basisty N, Gitari L, Rabinovitch PS. Mitochondrial dysfunction in cardiac aging. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1424-33. [PMID: 26191650 DOI: 10.1016/j.bbabio.2015.07.009] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 07/06/2015] [Accepted: 07/09/2015] [Indexed: 02/07/2023]
Abstract
Cardiovascular diseases are the leading cause of death in most developed nations. While it has received the least public attention, aging is the dominant risk factor for developing cardiovascular diseases, as the prevalence of cardiovascular diseases increases dramatically with increasing age. Cardiac aging is an intrinsic process that results in impaired cardiac function, along with cellular and molecular changes. Mitochondria play a great role in these processes, as cardiac function is an energetically demanding process. In this review, we examine mitochondrial dysfunction in cardiac aging. Recent research has demonstrated that mitochondrial dysfunction can disrupt morphology, signaling pathways, and protein interactions; conversely, mitochondrial homeostasis is maintained by mechanisms that include fission/fusion, autophagy, and unfolded protein responses. Finally, we describe some of the recent findings in mitochondrial targeted treatments to help meet the challenges of mitochondrial dysfunction in aging.
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Affiliation(s)
- Autumn Tocchi
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, USA.
| | - Ellen K Quarles
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, USA.
| | - Nathan Basisty
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, USA.
| | - Lemuel Gitari
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, USA.
| | - Peter S Rabinovitch
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, USA.
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9
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Hollander JM, Thapa D, Shepherd DL. Physiological and structural differences in spatially distinct subpopulations of cardiac mitochondria: influence of cardiac pathologies. Am J Physiol Heart Circ Physiol 2014; 307:H1-14. [PMID: 24778166 DOI: 10.1152/ajpheart.00747.2013] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cardiac tissue contains discrete pools of mitochondria that are characterized by their subcellular spatial arrangement. Subsarcolemmal mitochondria (SSM) exist below the cell membrane, interfibrillar mitochondria (IFM) reside in rows between the myofibrils, and perinuclear mitochondria are situated at the nuclear poles. Microstructural imaging of heart tissue coupled with the development of differential isolation techniques designed to sequentially separate spatially distinct mitochondrial subpopulations have revealed differences in morphological features including shape, absolute size, and internal cristae arrangement. These findings have been complemented by functional studies indicating differences in biochemical parameters and, potentially, functional roles for the ATP generated, based upon subcellular location. Consequently, mitochondrial subpopulations appear to be influenced differently during cardiac pathologies including ischemia/reperfusion, heart failure, aging, exercise, and diabetes mellitus. These influences may be the result of specific structural and functional disparities between mitochondrial subpopulations such that the stress elicited by a given cardiac insult differentially impacts subcellular locales and the mitochondria contained within. The goal of this review is to highlight some of the inherent structural and functional differences that exist between spatially distinct cardiac mitochondrial subpopulations as well as provide an overview of the differential impact of various cardiac pathologies on spatially distinct mitochondrial subpopulations. As an outcome, we will instill a basis for incorporating subcellular spatial location when evaluating the impact of cardiac pathologies on the mitochondrion. Incorporation of subcellular spatial location may offer the greatest potential for delineating the influence of cardiac pathology on this critical organelle.
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10
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Croston TL, Thapa D, Holden AA, Tveter KJ, Lewis SE, Shepherd DL, Nichols CE, Long DM, Olfert IM, Jagannathan R, Hollander JM. Functional deficiencies of subsarcolemmal mitochondria in the type 2 diabetic human heart. Am J Physiol Heart Circ Physiol 2014; 307:H54-65. [PMID: 24778174 DOI: 10.1152/ajpheart.00845.2013] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The mitochondrion has been implicated in the development of diabetic cardiomyopathy. Examination of cardiac mitochondria is complicated by the existence of spatially distinct subpopulations including subsarcolemmal (SSM) and interfibrillar (IFM). Dysfunction to cardiac SSM has been reported in murine models of type 2 diabetes mellitus; however, subpopulation-based mitochondrial analyses have not been explored in type 2 diabetic human heart. The goal of this study was to determine the impact of type 2 diabetes mellitus on cardiac mitochondrial function in the human patient. Mitochondrial subpopulations from atrial appendages of patients with and without type 2 diabetes were examined. Complex I- and fatty acid-mediated mitochondrial respiration rates were decreased in diabetic SSM compared with nondiabetic (P ≤ 0.05 for both), with no change in IFM. Electron transport chain (ETC) complexes I and IV activities were decreased in diabetic SSM compared with nondiabetic (P ≤ 0.05 for both), with a concomitant decline in their levels (P ≤ 0.05 for both). Regression analyses comparing comorbidities determined that diabetes mellitus was the primary factor accounting for mitochondrial dysfunction. Linear spline models examining correlative risk for mitochondrial dysfunction indicated that patients with diabetes display the same degree of state 3 and electron transport chain complex I dysfunction in SSM regardless of the extent of glycated hemoglobin (HbA1c) and hyperglycemia. Overall, the results suggest that independent of other pathologies, mitochondrial dysfunction is present in cardiac SSM of patients with type 2 diabetes and the degree of dysfunction is consistent regardless of the extent of elevated HbA1c or blood glucose levels.
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Affiliation(s)
- Tara L Croston
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory Sciences, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Dharendra Thapa
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory Sciences, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Anthony A Holden
- West Virginia University School of Medicine, Department of Surgery, Morgantown, West Virginia
| | - Kevin J Tveter
- West Virginia University School of Medicine, Department of Surgery, Morgantown, West Virginia
| | - Sara E Lewis
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory Sciences, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Danielle L Shepherd
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory Sciences, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Cody E Nichols
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory Sciences, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Dustin M Long
- West Virginia University School of Public Health, Department of Biostatistics, Morgantown, West Virginia
| | - I Mark Olfert
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory Sciences, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Rajaganapathi Jagannathan
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory Sciences, West Virginia University School of Medicine, Morgantown, West Virginia
| | - John M Hollander
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory Sciences, West Virginia University School of Medicine, Morgantown, West Virginia;
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11
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He Q, Han X. Cardiolipin remodeling in diabetic heart. Chem Phys Lipids 2013; 179:75-81. [PMID: 24189589 DOI: 10.1016/j.chemphyslip.2013.10.007] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 10/10/2013] [Accepted: 10/20/2013] [Indexed: 11/19/2022]
Abstract
Cardiolipin, a signature phospholipid of mitochondria, is predominantly present in the mitochondrial inner membrane and plays an important role in keeping optimal mitochondrial function. In addition to the cardiolipin content, the composition of four fatty acid chain is thought determine cardiolipin biological function. These acyl chains of cardiolipin are dynamically remodeled via tafazzin, monolysocardiolipin acyltransferase, and acyl-CoA lysocardiolipin acyltransferase especially in the heart under pathological conditions. The major species of cardiolipin in the normal heart, tetralinoleoyl cardiolipin, is dramatically decreased in the diabetic heart, but other species, typically those containing long fatty acyl chains, are increased. This remodeling of cardiolipin has detrimental effects on mitochondrial function and thereafter cardiac function. Approaches for manipulating cardiolipin acyl chains have been examined including via molecular biology and through supplementation of linoleic acid. The efficiency of cardiolipin remodeling and functional improvement is still under investigation.
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Affiliation(s)
- Quan He
- Diabetes and Obesity Research Center, Sanford-Burnham Medical Research Institute, Orlando, FL 32827, USA
| | - Xianlin Han
- Diabetes and Obesity Research Center, Sanford-Burnham Medical Research Institute, Orlando, FL 32827, USA.
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12
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Hardeland R. Melatonin and the theories of aging: a critical appraisal of melatonin's role in antiaging mechanisms. J Pineal Res 2013; 55:325-56. [PMID: 24112071 DOI: 10.1111/jpi.12090] [Citation(s) in RCA: 189] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 08/23/2013] [Indexed: 02/06/2023]
Abstract
The classic theories of aging such as the free radical theory, including its mitochondria-related versions, have largely focused on a few specific processes of senescence. Meanwhile, numerous interconnections have become apparent between age-dependent changes previously thought to proceed more or less independently. Increased damage by free radicals is not only linked to impairments of mitochondrial function, but also to inflammaging as it occurs during immune remodeling and by release of proinflammatory cytokines from mitotically arrested, DNA-damaged cells that exhibit the senescence-associated secretory phenotype (SASP). Among other effects, SASP can cause mutations in stem cells that reduce the capacity for tissue regeneration or, in worst case, lead to cancer stem cells. Oxidative stress has also been shown to promote telomere attrition. Moreover, damage by free radicals is connected to impaired circadian rhythmicity. Another nexus exists between cellular oscillators and metabolic sensing, in particular to the aging-suppressor SIRT1, which acts as an accessory clock protein. Melatonin, being a highly pleiotropic regulator molecule, interacts directly or indirectly with all the processes mentioned. These influences are critically reviewed, with emphasis on data from aged organisms and senescence-accelerated animals. The sometimes-controversial findings obtained either in a nongerontological context or in comparisons of tumor with nontumor cells are discussed in light of evidence obtained in senescent organisms. Although, in mammals, lifetime extension by melatonin has been rarely documented in a fully conclusive way, a support of healthy aging has been observed in rodents and is highly likely in humans.
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Affiliation(s)
- Rüdiger Hardeland
- Johann Friedrich Blumenbach Institute of Zoology and Anthropology, University of Göttingen, Göttingen, Germany
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13
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Monteiro JP, Oliveira PJ, Jurado AS. Mitochondrial membrane lipid remodeling in pathophysiology: a new target for diet and therapeutic interventions. Prog Lipid Res 2013; 52:513-28. [PMID: 23827885 DOI: 10.1016/j.plipres.2013.06.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 06/14/2013] [Accepted: 06/17/2013] [Indexed: 12/22/2022]
Abstract
Mitochondria are arbiters in the fragile balance between cell life and death. These organelles present an intricate membrane system, with a peculiar lipid composition and displaying transverse as well as lateral asymmetry. Some lipids are synthesized inside mitochondria, while others have to be imported or acquired in the form of precursors. Here, we review different processes, including external interventions (e.g., diet) and a range of biological events (apoptosis, disease and aging), which may result in alterations of mitochondrial membrane lipid content. Cardiolipin, the mitochondria lipid trademark, whose biosynthetic pathway is highly regulated, will deserve special attention in this review. The modulation of mitochondrial membrane lipid composition, especially by diet, as a therapeutic strategy for the treatment of some pathologies will be also addressed.
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Affiliation(s)
- João P Monteiro
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Department of Life Sciences, University of Coimbra, Portugal
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14
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Lesnefsky EJ, Hoppel CL. Aged rat heart: Modulation of age-related respiratory defects decreases ischemic-reflow injury. Health (London) 2013. [DOI: 10.4236/health.2013.51001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Changes in the mitochondrial permeability transition pore in aging and age-associated diseases. Mech Ageing Dev 2012; 134:1-9. [PMID: 23287740 DOI: 10.1016/j.mad.2012.12.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 12/13/2012] [Accepted: 12/19/2012] [Indexed: 12/26/2022]
Abstract
Aging is a biological process associated with impairment of mitochondrial bioenergetic function, increased oxidative stress, attenuated ability to respond to stresses and increased risk in contracting age-associated diseases. When mitochondria are subjected to oxidative stress, accompanied by calcium overload and ATP depletion, they undergo "a permeability transition", characterized by sudden induced change of the inner mitochondrial membrane permeability for water as well as for low-molecular weight solutes (≤1.5kDa), resulting in membrane depolarization and uncoupling of oxidative phosphorylation. Research interest in the entity responsible for this phenomenon, the "mitochondrial permeability transition pore" (MPTP) has dramatically increased after demonstration that it plays a key role in the life and death decision in cells. The molecular structure and identity of MPTP is not yet known, although the pore is thought to exist as multiprotein complex. Some evidence indicate that the sensitivity of mitochondria to Ca(2+)-induced MPTP opening increases with aging; however the basis of this difference is unknown. Changes in MPTP structure and/or function may have important implications in the aging process and aged-associated diseases. This article examines data relevant to this issue. The important role of a principal lipidic counter-partner of the MPTP, cardiolipin, will also be discussed.
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Kim J, Hoppel CL. Comprehensive approach to the quantitative analysis of mitochondrial phospholipids by HPLC-MS. J Chromatogr B Analyt Technol Biomed Life Sci 2012; 912:105-14. [PMID: 23266842 DOI: 10.1016/j.jchromb.2012.10.036] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 10/22/2012] [Accepted: 10/30/2012] [Indexed: 02/02/2023]
Abstract
A normal-phase HPLC-MS method was established to analyze mitochondrial phospholipids quantitatively as well as qualitatively. An efficient extraction procedure and chromatographic conditions were developed using twelve standardized phospholipids and lysophospholipids. The chromatographic conditions provided physical separation of phospholipids by class, and efficient ionization allowed detection of low abundance phospholipids such as phosphatidylglycerol and monolysocardiolipin. The chromatographic separation of each class of phospholipid permitted qualitative identification of molecular species without interference from other classes. This is advantageous for mitochondrial lipidomics because the composition of mitochondrial phospholipids varies depending on tissue source, pathological condition, and nutrition. Using the method, seven classes of phospholipids (phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, cardiolipin, and monolysocardiolipin) were detected in rat heart and skeletal muscle mitochondria and all but phosphatidylserine were quantified. The concentration was calculated using standard curves with an internal standard generated for each class of phospholipid. The method was validated for intraday and interday variation and showed excellent reproducibility and accuracy. This new method, with each step documented, provides a powerful tool for accurate quantitation of phospholipids, a basic structural component of mitochondrial membranes.
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Affiliation(s)
- Junhwan Kim
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, United States
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Blockade of electron transport at the onset of reperfusion decreases cardiac injury in aged hearts by protecting the inner mitochondrial membrane. J Aging Res 2012; 2012:753949. [PMID: 22619720 PMCID: PMC3347723 DOI: 10.1155/2012/753949] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 11/23/2011] [Accepted: 12/27/2011] [Indexed: 12/23/2022] Open
Abstract
Myocardial injury is increased in the aged heart following ischemia-reperfusion (ISC-REP) compared to adult hearts. Intervention at REP with ischemic postconditioning decreases injury in the adult heart by attenuating mitochondrial driven cell injury. Unfortunately, postconditioning is ineffective in aged hearts. Blockade of electron transport at the onset of REP with the reversible inhibitor amobarbital (AMO) decreases injury in adult hearts. We tested if AMO treatment at REP protects the aged heart via preservation of mitochondrial integrity. Buffer-perfused elderly Fischer 344 24 mo. rat hearts underwent 25 min global ISC and 30 min REP. AMO (2.5 mM) or vehicle was given for 3 min at the onset of REP. Subsarcolemmal (SSM) and interfibrillar (IFM) mitochondria were isolated after REP. Oxidative phosphorylation (OXPHOS) and mitochondrial inner membrane potential were measured. AMO treatment at REP decreased cardiac injury. Compared to untreated ISC-REP, AMO improved inner membrane potential in SSM and IFM during REP, indicating preserved inner membrane integrity. Thus, direct pharmacologic modulation of electron transport at REP protects mitochondria and decreases cardiac injury in the aged heart, even when signaling-induced pathways of postconditioning that are upstream of mitochondria are ineffective.
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Gómez LA, Hagen TM. Age-related decline in mitochondrial bioenergetics: does supercomplex destabilization determine lower oxidative capacity and higher superoxide production? Semin Cell Dev Biol 2012; 23:758-67. [PMID: 22521482 DOI: 10.1016/j.semcdb.2012.04.002] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 03/31/2012] [Accepted: 04/04/2012] [Indexed: 12/17/2022]
Abstract
Mitochondrial decay plays a central role in the aging process. Although certainly multifactorial in nature, defective operation of the electron transport chain (ETC) constitutes a key mechanism involved in the age-associated loss of mitochondrial energy metabolism. Primarily, mitochondrial dysfunction affects the aging animal by limiting bioenergetic reserve capacity and/or increasing oxidative stress via enhanced electron leakage from the ETC. Even though the important aging characteristics of mitochondrial decay are known, the molecular events underlying inefficient electron flux that ultimately leads to higher superoxide appearance and impaired respiration are not completely understood. This review focuses on the potential role(s) that age-associated destabilization of the macromolecular organization of the ETC (i.e. supercomplexes) may be important for development of the mitochondrial aging phenotype, particularly in post-mitotic tissues.
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Affiliation(s)
- Luis A Gómez
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA
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Fujioka H, Moghaddas S, Murdock DG, Lesnefsky EJ, Tandler B, Hoppel CL. Decreased cytochrome c oxidase subunit VIIa in aged rat heart mitochondria: immunocytochemistry. Anat Rec (Hoboken) 2011; 294:1825-33. [PMID: 21972221 DOI: 10.1002/ar.21486] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 03/29/2011] [Accepted: 07/24/2011] [Indexed: 12/26/2022]
Abstract
Aging decreases oxidative phosphorylation through cytochrome oxidase (COX) in cardiac interfibrillar mitochondria (IFM) in 24-month old (aged) rats compared to 6-month old adult Fischer 344 rats, whereas subsarcolemmal mitochondria (SSM) located beneath the plasma membrane remain unaffected. Immunoelectron microscopy (IEM) reveals in aged rats a 25% reduction in cardiac COX subunit VIIa in cardiac IFM, but not in SSM. In contrast, the content of subunit IV remains unchanged in both SSM and IFM, irrespective of age. These subunits are localized mainly on cristae membranes. In contrast, semi-quantitative immunoblotting, which detects denatured protein, indicates that the content of COX VIIa is similar in IFM and SSM from both aged and adult hearts. IEM provides a sensitive method for precise localizing and quantifying specific mitochondrial proteins. The lack of immunoreaction of COX VIIa subunit by IEM in aged IFM is not explained by a reduction in protein, but rather by a masking phenomenon or by an in situ change in protein structure affecting COX activity.
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Affiliation(s)
- Hisashi Fujioka
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA.
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20
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Lemieux H, Vazquez EJ, Fujioka H, Hoppel CL. Decrease in mitochondrial function in rat cardiac permeabilized fibers correlates with the aging phenotype. J Gerontol A Biol Sci Med Sci 2010; 65:1157-64. [PMID: 20801909 DOI: 10.1093/gerona/glq141] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We measured the loss of cardiac mitochondrial function related to aging in males of three rat strains presenting with different longevity and aging phenotypes: the Fischer 344 (F344), the Brown Norway (BN), and the hybrid F344×BN. The F344 rat has a short life span and a ∼45% decrease in coupled mitochondrial oxidation in the cardiac permeabilized fibers from the old rats compared with the young rats. Citrate synthase activity in the permeabilized fibers (mitochondrial content) did not change significantly with aging. The BN live longer compared with the F344 and have a 15%-18% loss of mitochondrial respiration in the aged rats compared with the young rats. The differences are not significant. In hybrids, more resistant to aging than are the BN and the F344, mitochondrial function is preserved during aging. The difference in longevity of the different strains is correlated with mitochondrial dysfunction in the heart, suggesting the importance of mitochondria in cardiac aging.
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Affiliation(s)
- Hélène Lemieux
- Center for Mitochondrial Disease, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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Kiebish MA, Bell R, Yang K, Phan T, Zhao Z, Ames W, Seyfried TN, Gross RW, Chuang JH, Han X. Dynamic simulation of cardiolipin remodeling: greasing the wheels for an interpretative approach to lipidomics. J Lipid Res 2010; 51:2153-70. [PMID: 20410019 DOI: 10.1194/jlr.m004796] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Cardiolipin is a class of mitochondrial specific phospholipid, which is intricately involved in mitochondrial functionality. Differences in cardiolipin species exist in a variety of tissues and diseases. It has been demonstrated that the cardiolipin profile is a key modulator of the functions of many mitochondrial proteins. However, the chemical mechanism(s) leading to normal and/or pathological distribution of cardiolipin species remain elusive. Herein, we describe a novel approach for investigating the molecular mechanism of cardiolipin remodeling through a dynamic simulation. This approach applied data from shotgun lipidomic analyses of the heart, liver, brain, and lung mitochondrial lipidomes to model cardiolipin remodeling, including relative content, regiospecificity, and isomeric composition of cardiolipin species. Generated cardiolipin profiles were nearly identical to those determined by shotgun lipidomics. Importantly, the simulated isomeric compositions of cardiolipin species were further substantiated through product ion analysis. Finally, unique enzymatic activities involved in cardiolipin remodeling were assessed from the parameters used in the dynamic simulation of cardiolipin profiles. Collectively, we described, verified, and demonstrated a novel approach by integrating both lipidomic analysis and dynamic simulation to study cardiolipin biology. We believe this study provides a foundation to investigate cardiolipin metabolism and bioenergetic homeostasis in normal and disease states.
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Affiliation(s)
- Michael A Kiebish
- Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine, St Louis, MO 63110, USA
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Ljubicic V, Menzies KJ, Hood DA. Mitochondrial dysfunction is associated with a pro-apoptotic cellular environment in senescent cardiac muscle. Mech Ageing Dev 2010; 131:79-88. [DOI: 10.1016/j.mad.2009.12.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 11/25/2009] [Accepted: 12/18/2009] [Indexed: 10/20/2022]
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Doenst T, Pytel G, Schrepper A, Amorim P, Färber G, Shingu Y, Mohr FW, Schwarzer M. Decreased rates of substrate oxidation ex vivo predict the onset of heart failure and contractile dysfunction in rats with pressure overload. Cardiovasc Res 2009; 86:461-70. [PMID: 20035032 DOI: 10.1093/cvr/cvp414] [Citation(s) in RCA: 189] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Left ventricular hypertrophy is a risk factor for heart failure. However, it also is a compensatory response to pressure overload, accommodating for increased workload. We tested whether the changes in energy substrate metabolism may be predictive for the development of contractile dysfunction. METHODS AND RESULTS Chronic pressure overload was induced in Sprague-Dawley rats by aortic arch constriction for 2, 6, 10, or 20 weeks. Contractile function in vivo was assessed by echocardiography and by invasive pressure measurement. Glucose and fatty acid oxidation as well as contractile function ex vivo were assessed in the isolated working heart, and respiratory capacity was measured in isolated cardiac mitochondria. Pressure overload caused progressive hypertrophy with normal ejection fraction (EF) at 2, 6, and 10 weeks, and hypertrophy with dilation and impaired EF at 20 weeks. The lung-to-body weight ratio, as marker for pulmonary congestion, was normal at 2 weeks (indicative of compensated hypertrophy) but significantly increased already after 6 and up to 20 weeks, suggesting the presence of heart failure with normal EF at 6 and 10 weeks and impaired EF at 20 weeks. Invasive pressure measurements showed evidence for contractile dysfunction already after 6 weeks and ex vivo cardiac power was reduced even at 2 weeks. Importantly, there was impairment in fatty acid oxidation beginning at 2 weeks, which was associated with a progressive decrease in glucose oxidation. In contrast, respiratory capacity of isolated mitochondria was normal until 10 weeks and decreased only in hearts with impaired EF. CONCLUSION Pressure overload-induced impairment in fatty acid oxidation precedes the onset of congestive heart failure but mitochondrial respiratory capacity is maintained until the EF decreases in vivo. These temporal relations suggest a tight link between impaired substrate oxidation capacity in the development of heart failure and contractile dysfunction and may imply therapeutic and prognostic value.
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Affiliation(s)
- Torsten Doenst
- Department of Cardiac Surgery, University of Leipzig, Heart Center Leipzig, Strümpellstr. 39, 04289 Leipzig, Germany.
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Rosca MG, Lemieux H, Hoppel CL. Mitochondria in the elderly: Is acetylcarnitine a rejuvenator? Adv Drug Deliv Rev 2009; 61:1332-1342. [PMID: 19720100 DOI: 10.1016/j.addr.2009.06.009] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Accepted: 06/01/2009] [Indexed: 12/21/2022]
Abstract
Endogenous acetylcarnitine is an indicator of acetyl-CoA synthesized by multiple metabolic pathways involving carbohydrates, amino acids, fatty acids, sterols, and ketone bodies, and utilized mainly by the tricarboxylic acid cycle. Acetylcarnitine supplementation has beneficial effects in elderly animals and humans, including restoration of mitochondrial content and function. These effects appear to be dose-dependent and occur even after short-term therapy. In order to set the stage for understanding the mechanism of action of acetylcarnitine, we review the metabolism and role of this compound. We suggest that acetylation of mitochondrial proteins leads to a specific increase in mitochondrial gene expression and mitochondrial protein synthesis. In the aged rat heart, this effect is translated to increased cytochrome b content, restoration of complex III activity, and oxidative phosphorylation, resulting in amelioration of the age-related mitochondrial defect.
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Affiliation(s)
- Mariana G Rosca
- Center for Mitochondrial Diseases and Departments of Medicine and Pharmacology, Case Western Reserve University, Cleveland, Ohio
| | - Hélène Lemieux
- Center for Mitochondrial Diseases and Departments of Medicine and Pharmacology, Case Western Reserve University, Cleveland, Ohio
| | - Charles L Hoppel
- Center for Mitochondrial Diseases and Departments of Medicine and Pharmacology, Case Western Reserve University, Cleveland, Ohio
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Gómez LA, Monette JS, Chavez JD, Maier CS, Hagen TM. Supercomplexes of the mitochondrial electron transport chain decline in the aging rat heart. Arch Biochem Biophys 2009; 490:30-5. [PMID: 19679098 DOI: 10.1016/j.abb.2009.08.002] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Revised: 08/03/2009] [Accepted: 08/04/2009] [Indexed: 01/06/2023]
Abstract
Accumulation of mitochondrial electron transport chain (ETC) defects is a recognized hallmark of the age-associated decline in cardiac bioenergetics; however, the molecular events involved are only poorly understood. In the present work, we hypothesized that age-related ETC deterioration stemmed partly from disassociation of large solid-state macromolecular assemblies termed "supercomplexes". Mitochondrial proteins from young and old rat hearts were separated by blue native-PAGE, protein bands analyzed by LC-MALDI-MS/MS, and protein levels quantified by densitometry. Results showed that supercomplexes comprised of various stoichiometries of complexes I, III and IV were observed, and declined significantly (p<0.05, n=4) with age. Supercomplexes displaying the highest molecular masses were the most severely affected. Considering that certain diseases (e.g. Barth Syndrome) display similar supercomplex destabilization as our results for aging, the deterioration in ETC supercomplexes may be an important underlying factor for both impaired mitochondrial function and loss of cardiac bioenergetics with age.
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Affiliation(s)
- Luis A Gómez
- Linus Pauling Institute and Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
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26
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Hofer T, Servais S, Seo AY, Marzetti E, Hiona A, Upadhyay SJ, Wohlgemuth SE, Leeuwenburgh C. Bioenergetics and permeability transition pore opening in heart subsarcolemmal and interfibrillar mitochondria: effects of aging and lifelong calorie restriction. Mech Ageing Dev 2009; 130:297-307. [PMID: 19428447 PMCID: PMC2680750 DOI: 10.1016/j.mad.2009.01.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 01/12/2009] [Accepted: 01/21/2009] [Indexed: 10/21/2022]
Abstract
Loss of cardiac mitochondrial function with age may cause increased cardiomyocyte death through mitochondria-mediated release of apoptogenic factors. We investigated ventricular subsarcolemmal (SSM) and interfibrillar (IFM) mitochondrial bioenergetics and susceptibility towards Ca(2+)-induced permeability transition pore (mPTP) opening with aging and lifelong calorie restriction (CR). Cardiac mitochondria were isolated from 8-, 18-, 29- and 37-month-old male Fischer 344 x Brown Norway rats fed either ad libitum (AL) or 40% calorie restricted diets. With age, H(2)O(2) generation did not increase and oxygen consumption did not significantly decrease in either SSM or IFM. Strikingly, IFM displayed an increased susceptibility towards mPTP opening during senescence. In contrast, Ca(2+) retention capacity of SSM was not affected by age, but SSM tolerated much less Ca(2+) than IFM. Only modest age-dependent increases in cytosolic caspase activities and cytochrome c levels were observed and were not affected by CR. Levels of putative mPTP-modulating components: cyclophilin-D, the adenine nucleotide translocase (ANT), and the voltage-dependent ion channel (VDAC) were not affected by aging or CR. In summary, the age-related reduction of Ca(2+) retention capacity in IFM may explain the increased susceptibility to stress-induced cell death in the aged myocardium.
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Affiliation(s)
- Tim Hofer
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
| | - Stephane Servais
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
| | - Arnold Young Seo
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
| | - Emanuele Marzetti
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
- Department of Gerontology, Geriatrics and Physiatrics, Catholic University of the Sacret Heart, Rome 00168, Italy
| | - Asimina Hiona
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
| | - Shashank Jagdish Upadhyay
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
| | - Stephanie Eva Wohlgemuth
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
| | - Christiaan Leeuwenburgh
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
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Lesnefsky EJ, Minkler P, Hoppel CL. Enhanced modification of cardiolipin during ischemia in the aged heart. J Mol Cell Cardiol 2009; 46:1008-15. [PMID: 19303420 DOI: 10.1016/j.yjmcc.2009.03.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2008] [Revised: 03/04/2009] [Accepted: 03/05/2009] [Indexed: 11/26/2022]
Abstract
Aging enhances cardiac injury during ischemia and reperfusion compared to the adult heart, including in the Fischer 344 rat model of aging (F344). In interfibrillar cardiac mitochondria obtained from the elderly F344 rat, the rate of oxidative phosphorylation and the activity of electron transport complex III is decreased, concomitant with an increase in the production of reactive oxygen species. In the isolated, perfused heart, 25 min of global ischemia results in additional damage to complex III. We proposed that ischemic damage superimposed upon the aging defect augments production of reactive oxygen species leading to greater oxidative damage in the aged heart. Cardiolipin is an oxidatively sensitive phospholipid located in the inner mitochondrial membrane. Oxidative damage to cardiolipin was assessed by characterization of the individual molecular species of cardiolipin via reverse phase HPLC and electrospray mass spectrometry (MS). The predominant molecular species of cardiolipin (95%) contains four linoleic acid residues (C18:2). Ischemia and reperfusion did not alter the content or composition of cardiolipin in the adult heart. Following ischemia and reperfusion in the aged heart, a new molecular species of cardiolipin was present with mass increased by 48 Da, suggesting the addition of three oxygen atoms. MS fragmentation localized the added mass to the C18:2 residues. Ischemia alone was sufficient to modify cardiolipin in the aged heart whereas cardiolipin in the adult heart remained unaltered. Thus, age-enhanced oxidative damage occurs within mitochondria in the heart during ischemia and reperfusion, especially during ischemia.
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Affiliation(s)
- Edward J Lesnefsky
- Department of Medicine, Division of Cardiology, Case Western Reserve University, Cleveland, OH 44106, USA
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Rennison JH, McElfresh TA, Chen X, Anand VR, Hoit BD, Hoppel CL, Chandler MP. Prolonged exposure to high dietary lipids is not associated with lipotoxicity in heart failure. J Mol Cell Cardiol 2009; 46:883-90. [PMID: 19265702 DOI: 10.1016/j.yjmcc.2009.02.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 02/18/2009] [Accepted: 02/19/2009] [Indexed: 12/15/2022]
Abstract
Previous studies have reported that elevated myocardial lipids in a model of mild-to-moderate heart failure increased mitochondrial function, but did not alter left ventricular function. Whether more prolonged exposure to high dietary lipids would promote a lipotoxic phenotype in mitochondrial and myocardial contractile function has not been determined. We tested the hypothesis that prolonged exposure to high dietary lipids, following coronary artery ligation, would preserve myocardial and mitochondrial function in heart failure. Rats underwent ligation or sham surgery and were fed normal (10% kcal fat) (SHAM, HF) or high fat diet (60% kcal saturated fat) (SHAM+FAT, HF+FAT) for sixteen weeks. Although high dietary fat was accompanied by myocardial tissue triglyceride accumulation (SHAM 1.47+/-0.14; SHAM+FAT 2.32+/-0.14; HF 1.34+/-0.14; HF+FAT 2.21+/-0.20 micromol/gww), fractional shortening was increased 16% in SHAM+FAT and 28% in HF+FAT compared to SHAM and HF, respectively. Despite increased medium-chain acyl-CoA dehydrogenase (MCAD) activity in interfibrillar mitochondria (IFM) of both SHAM+FAT and HF+FAT, dietary lipids also were associated with decreased state 3 respiration using palmitoylcarnitine (SHAM 369+/-14; SHAM+FAT 307+/-23; HF 354+/-13; HF+FAT 366+/-18 nAO min(-1) mg(-1)) in SHAM+FAT compared to SHAM and HF+FAT. State 3 respiration in IFM also was decreased in SHAM+FAT relative to SHAM using succinate and DHQ. In conclusion, high dietary lipids promoted myocardial lipid accumulation, but were not accompanied by alterations in myocardial contractile function typically associated with lipotoxicity. In normal animals, high dietary fat decreased mitochondrial respiration, but also increased MCAD activity. These studies support the concept that high fat feeding can modify multiple cellular pathways that differentially affect mitochondrial function under normal and pathological conditions.
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Affiliation(s)
- Julie H Rennison
- Department of Physiology and Biophysics, School of Medicine E558, Case Western Reserve University, Cleveland, OH 44106-4970, USA
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Huang JH, Hood DA. Age-associated mitochondrial dysfunction in skeletal muscle: Contributing factors and suggestions for long-term interventions. IUBMB Life 2009; 61:201-14. [DOI: 10.1002/iub.164] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Dabkowski ER, Williamson CL, Bukowski VC, Chapman RS, Leonard SS, Peer CJ, Callery PS, Hollander JM. Diabetic cardiomyopathy-associated dysfunction in spatially distinct mitochondrial subpopulations. Am J Physiol Heart Circ Physiol 2009; 296:H359-69. [PMID: 19060128 PMCID: PMC2643887 DOI: 10.1152/ajpheart.00467.2008] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Accepted: 12/02/2008] [Indexed: 01/12/2023]
Abstract
Diabetic cardiomyopathy is the leading cause of heart failure among diabetic patients, and mitochondrial dysfunction has been implicated as an underlying cause in the pathogenesis. Cardiac mitochondria consist of two spatially, functionally, and morphologically distinct subpopulations, termed subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM). SSM are situated beneath the plasma membrane, whereas IFM are embedded between myofibrils. The goal of this study was to determine whether spatially distinct cardiac mitochondrial subpopulations respond differently to a diabetic phenotype. Swiss-Webster mice were subjected to intraperitoneal injections of streptozotocin or citrate saline vehicle. Five weeks after injections, diabetic hearts displayed decreased rates of contraction, relaxation, and left ventricular developed pressures (P < 0.05 for all three). Both mitochondrial size (forward scatter, P < 0.01) and complexity (side scatter, P < 0.01) were decreased in diabetic IFM but not diabetic SSM. Electron transport chain complex II respiration was decreased in diabetic SSM (P < 0.05) and diabetic IFM (P < 0.01), with the decrease being greater in IFM. Furthermore, IFM complex I respiration and complex III activity were decreased with diabetes (P < 0.01) but were unchanged in SSM. Superoxide production was increased only in diabetic IFM (P < 0.01). Oxidative damage to proteins and lipids, indexed through nitrotyrosine residues and lipid peroxidation, were higher in diabetic IFM (P < 0.05 and P < 0.01, respectively). The mitochondria-specific phospholipid cardiolipin was decreased in diabetic IFM (P < 0.01) but not SSM. These results indicate that diabetes mellitus imposes a greater stress on the IFM subpopulation, which is associated, in part, with increased superoxide generation and oxidative damage, resulting in morphological and functional abnormalities that may contribute to the pathogenesis of diabetic cardiomyopathy.
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Affiliation(s)
- Erinne R Dabkowski
- Division of Exercise Physiology, Center for Interdisciplinary Research in Cardiovascular Sciences, West Virginia University School of Medicine, Morgantown, WV, USA
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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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Dabkowski ER, Williamson CL, Hollander JM. Mitochondria-specific transgenic overexpression of phospholipid hydroperoxide glutathione peroxidase (GPx4) attenuates ischemia/reperfusion-associated cardiac dysfunction. Free Radic Biol Med 2008; 45:855-65. [PMID: 18638546 DOI: 10.1016/j.freeradbiomed.2008.06.021] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Revised: 05/23/2008] [Accepted: 06/12/2008] [Indexed: 11/28/2022]
Abstract
Ischemia/reperfusion (I/R) injury elicits damage to mitochondria. Antioxidants provide protection from I/R-induced mitochondrial damage. The goal of this study was to determine the impact of mitochondria-specific overexpression of GPx4 (PHGPx) on cardiac function following I/R. Transgenic mice were created in which PHGPx was overexpressed solely in the mitochondrion (mPHGPx). MPHGPx and littermate control hearts were subjected to global no-flow ischemia (20 min) followed by reflow reperfusion (30, 60, and 90 min). Following I/R, mPHGPx hearts possessed significantly better rates of contraction, developed pressures, and peak-systolic pressures as compared to controls (P<0.05). No differences were observed in rates of relaxation or end-diastolic pressures. Lipid peroxidation was significantly lower in mitochondria from mPHGPx hearts as compared to controls, following I/R (P<0.05). Electron transport chain (ETC) complex I, III, and IV activities were significantly higher in mPHGPx hearts as compared to controls, following I/R (P<0.05). MPHGPx overexpression enhanced ETC complex I, III, and IV activities in subsarcolemmal mitochondria (SSM; P<0.05), and ETC complex I and III activities in interfibrillar mitochondria (IFM; P<0.05) following I/R. These results indicate that mitochondria-specific GPx4 overexpression protects cardiac contractile function and preserves ETC complex activities following I/R. These results provide further rationale for the use of mPHGPx as a therapeutic protectant.
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Affiliation(s)
- Erinne R Dabkowski
- West Virginia University School of Medicine, Division of Exercise Physiology, and Center for Interdisciplinary Research in Cardiovascular Sciences, 1 Medical Center Drive, Morgantown, WV 26506, USA
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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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Enhanced acyl-CoA dehydrogenase activity is associated with improved mitochondrial and contractile function in heart failure. Cardiovasc Res 2008; 79:331-40. [DOI: 10.1093/cvr/cvn066] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Bray MS, Shaw CA, Moore MWS, Garcia RAP, Zanquetta MM, Durgan DJ, Jeong WJ, Tsai JY, Bugger H, Zhang D, Rohrwasser A, Rennison JH, Dyck JRB, Litwin SE, Hardin PE, Chow CW, Chandler MP, Abel ED, Young ME. Disruption of the circadian clock within the cardiomyocyte influences myocardial contractile function, metabolism, and gene expression. Am J Physiol Heart Circ Physiol 2008; 294:H1036-47. [DOI: 10.1152/ajpheart.01291.2007] [Citation(s) in RCA: 261] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Virtually every mammalian cell, including cardiomyocytes, possesses an intrinsic circadian clock. The role of this transcriptionally based molecular mechanism in cardiovascular biology is poorly understood. We hypothesized that the circadian clock within the cardiomyocyte influences diurnal variations in myocardial biology. We, therefore, generated a cardiomyocyte-specific circadian clock mutant (CCM) mouse to test this hypothesis. At 12 wk of age, CCM mice exhibit normal myocardial contractile function in vivo, as assessed by echocardiography. Radiotelemetry studies reveal attenuation of heart rate diurnal variations and bradycardia in CCM mice (in the absence of conduction system abnormalities). Reduced heart rate persisted in CCM hearts perfused ex vivo in the working mode, highlighting the intrinsic nature of this phenotype. Wild-type, but not CCM, hearts exhibited a marked diurnal variation in responsiveness to an elevation in workload (80 mmHg plus 1 μM epinephrine) ex vivo, with a greater increase in cardiac power and efficiency during the dark (active) phase vs. the light (inactive) phase. Moreover, myocardial oxygen consumption and fatty acid oxidation rates were increased, whereas cardiac efficiency was decreased, in CCM hearts. These observations were associated with no alterations in mitochondrial content or structure and modest mitochondrial dysfunction in CCM hearts. Gene expression microarray analysis identified 548 and 176 genes in atria and ventricles, respectively, whose normal diurnal expression patterns were altered in CCM mice. These studies suggest that the cardiomyocyte circadian clock influences myocardial contractile function, metabolism, and gene expression.
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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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King KL, Stanley WC, Rosca M, Kerner J, Hoppel CL, Febbraio M. Fatty acid oxidation in cardiac and skeletal muscle mitochondria is unaffected by deletion of CD36. Arch Biochem Biophys 2007; 467:234-8. [PMID: 17904092 PMCID: PMC2702466 DOI: 10.1016/j.abb.2007.08.020] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Revised: 08/17/2007] [Accepted: 08/18/2007] [Indexed: 11/20/2022]
Abstract
Recent studies found that the plasma membrane fatty acid transport protein CD36 also resides in mitochondrial membranes in cardiac and skeletal muscle. Pharmacological studies suggest that CD36 may play an essential role in mitochondrial fatty acid oxidation. We isolated cardiac and skeletal muscle mitochondria from wild type and CD36 knock-out mice. There were no differences between wild type and CD36 knock-out mice in mitochondrial respiration with palmitoyl-CoA, palmitoyl-carnitine or glutamate as substrate. We investigated a potential alternative role for CD36 in mitochondria, i.e. the export of fatty acids generated in the matrix. Palmitate export was not different between wild type and CD36 knock-out mice. Taken together, CD36 does not appear to play an essential role in mitochondrial uptake of fatty acids or export of fatty acid anions.
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Affiliation(s)
- Kristen L. King
- Department of Physiology and Biophysics, Case Western Reserve University; Cleveland, USA
| | - William C. Stanley
- Department of Physiology and Biophysics, Case Western Reserve University; Cleveland, USA
- Department of Nutrition, Case Western Reserve University; Cleveland, USA
- Department of Medicine, Division of Cardiology, University of Maryland, Baltimore, USA
| | - Mariana Rosca
- Department of Pharmacology. School of Medicine, Case Western Reserve University; Cleveland, USA
| | - Janos Kerner
- Department of Nutrition, Case Western Reserve University; Cleveland, USA
| | - Charles L. Hoppel
- Department of Pharmacology. School of Medicine, Case Western Reserve University; Cleveland, USA
| | - Maria Febbraio
- Department of Cell Biology, Cleveland Clinic, Lerner Institute; Cleveland, USA
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Tanaka-Esposito C, Chen Q, Moghaddas S, Lesnefsky EJ. Ischemic preconditioning does not protect via blockade of electron transport. J Appl Physiol (1985) 2007; 103:623-8. [PMID: 17463293 DOI: 10.1152/japplphysiol.00943.2006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ischemic preconditioning (IPC) before sustained ischemia decreases myocardial infarct size mediated in part via protection of cardiac mitochondria. Reversible blockade of electron transport at complex I immediately before sustained ischemia also preserves mitochondrial respiration and decreases infarct size. We proposed that IPC would attenuate electron transport from complex I as a potential effector mechanism of cardioprotection. Isolated, Langendorff-perfused rat hearts underwent IPC (3 cycles of 5-min 37°C global ischemia and 5-min reperfusion) or were perfused for 40 min without ischemia as controls. Subsarcolemmal (SSM) and interfibrillar (IFM) populations of mitochondria were isolated. IPC did not decrease ADP-stimulated respiration measured in intact mitochondria using substrates that donate reducing equivalents to complex I. Maximally expressed complex I activity measured as rotenone-sensitive NADH:ubiquinone oxidoreductase in detergent-solubilized mitochondria was also unaffected by IPC. Thus the protection of IPC does not occur as a consequence of a partial decrease in complex I activity leading to a decrease in integrated respiration through complex I. IPC and blockade of electron transport both converge on mitochondria as effectors of cardioprotection; however, each modulates mitochondrial metabolism during ischemia by different mechanisms to achieve cardioprotection.
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Affiliation(s)
- Christine Tanaka-Esposito
- Division of Cardiology, Department of Medicine, School of Medicine, Case Western Reserve University, OH, USA
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40
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Sparagna GC, Chicco AJ, Murphy RC, Bristow MR, Johnson CA, Rees ML, Maxey ML, McCune SA, Moore RL. Loss of cardiac tetralinoleoyl cardiolipin in human and experimental heart failure. J Lipid Res 2007; 48:1559-70. [PMID: 17426348 DOI: 10.1194/jlr.m600551-jlr200] [Citation(s) in RCA: 190] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mitochondrial phospholipid cardiolipin is required for optimal mitochondrial respiration. In this study, cardiolipin molecular species and cytochrome oxidase (COx) activity were studied in interfibrillar (IF) and subsarcolemmal (SSL) cardiac mitochondria from Spontaneously Hypertensive Heart Failure (SHHF) and Sprague-Dawley (SD) rats throughout their natural life span. Fisher Brown Norway (FBN) and young aortic-constricted SHHF rats were also studied to investigate cardiolipin alterations in aging versus pathology. Additionally, cardiolipin was analyzed in human hearts explanted from patients with dilated cardiomyopathy. A loss of tetralinoleoyl cardiolipin (L(4)CL), the predominant species in the healthy mammalian heart, occurred during the natural or accelerated development of heart failure in SHHF rats and humans. L(4)CL decreases correlated with reduced COx activity (no decrease in protein levels) in SHHF cardiac mitochondria, but with no change in citrate synthase (a matrix enzyme) activity. The fraction of cardiac cardiolipin containing L(4)CL became much lower with age in SHHF than in SD or FBN mitochondria. In summary, a progressive loss of cardiac L(4)CL, possibly attributable to decreased remodeling, occurs in response to chronic cardiac overload, but not aging alone, in both IF and SSL mitochondria. This may contribute to mitochondrial respiratory dysfunction during the pathogenesis of heart failure.
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Affiliation(s)
- Genevieve C Sparagna
- Department of Integrative Physiology, University of Colorado Cardiovascular Institute, University of Colorado at Boulder, Boulder, CO 80309-0354, USA.
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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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42
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King KL, Young ME, Kerner J, Huang H, O'Shea KM, Alexson SEH, Hoppel CL, Stanley WC. Diabetes or peroxisome proliferator-activated receptor alpha agonist increases mitochondrial thioesterase I activity in heart. J Lipid Res 2007; 48:1511-7. [PMID: 17438340 DOI: 10.1194/jlr.m600364-jlr200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Peroxisome proliferator-activated receptor alpha (PPAR alpha) is a transcriptional regulator of the expression of mitochondrial thioesterase I (MTE-I) and uncoupling protein 3 (UCP3), which are induced in the heart at the mRNA level in response to diabetes. Little is known about the regulation of protein expression of MTE-I and UCP3 or about MTE-I activity; thus, we investigated the effects of diabetes and treatment with a PPAR alpha agonist on these parameters. Rats were either made diabetic with streptozotocin (55 mg/kg ip) and maintained for 10-14 days or treated with the PPAR alpha agonist fenofibrate (300 mg/kg/day) for 4 weeks. MTE-I and UCP3 protein expression, MTE-1 activity, palmitate export, and oxidative phosphorylation were measured in isolated cardiac mitochondria. Diabetes and fenofibrate increased cardiac MTE-I mRNA, protein, and activity ( approximately 4-fold compared with controls). This increase in activity was matched by a 6-fold increase in palmitate export in fenofibrate-treated animals, despite there being no effect in either group on UCP3 protein expression. Both diabetes and fenofibrate caused significant decreases in state III respiration of isolated mitochondria with pyruvate + malate as the substrate, but only diabetes reduced state III rates with palmitoylcarnitine. Both diabetes and specific PPAR alpha activation increased MTE-I protein, activity, and palmitate export in the heart, with little effect on UCP3 protein expression.
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Affiliation(s)
- Kristen L King
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
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43
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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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Riva A, Tandler B, Lesnefsky EJ, Conti G, Loffredo F, Vazquez E, Hoppel CL. Structure of cristae in cardiac mitochondria of aged rat. Mech Ageing Dev 2006; 127:917-21. [PMID: 17101170 PMCID: PMC1903371 DOI: 10.1016/j.mad.2006.09.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Revised: 08/15/2006] [Accepted: 09/07/2006] [Indexed: 11/18/2022]
Abstract
Interfibrillar mitochondria (IFM) of the heart in aged Fischer 344 rats show a biochemical defect which might be reflected in their morphology. We examined by high resolution scanning electron microscopy over 5500 mitochondria to determine if a concomitant structural alteration existed. This methodology provides a means of examining mitochondrial cristae in three dimensions. Cristae of in situ subsarcolemmal mitochondria (SSM) and of IFM in both 6- and 24-month-old Fischer rats are predominantly lamelliform. When isolated, these organelles, whether of SSM or IFM origin, display enhanced heterogeneity, but they have similar crista morphology irrespective of the age of the rat. Crista configuration does not play a major role in age-related cardiac mitochondrial defects.
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Affiliation(s)
- Alessandro Riva
- Department of Cytomorphology, University of Cagliari, Cagliari, Italy
| | - Bernard Tandler
- Department of Biological Sciences, School of Dental Medicine, Case Western Reserve University, and Medical Service
| | - Edward J. Lesnefsky
- Departments of Medicine (Divisions of Cardiology and Clinical Pharmacology), Case Western Reserve University, and Medical Service
- Louis Stokes Veterans Affairs Medical Center, Cleveland, Ohio 44106
| | - Gabriele Conti
- Department of Cytomorphology, University of Cagliari, Cagliari, Italy
| | - Felice Loffredo
- Department of Cytomorphology, University of Cagliari, Cagliari, Italy
| | - Edwin Vazquez
- School of Medicine, Case Western Reserve University, and Medical Service
| | - Charles L. Hoppel
- Department of Pharmacology, Case Western Reserve University, and Medical Service
- School of Medicine, Case Western Reserve University, and Medical Service
- Louis Stokes Veterans Affairs Medical Center, Cleveland, Ohio 44106
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45
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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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Crouser ED, Julian MW, Huff JE, Struck J, Cook CH. Carbamoyl phosphate synthase-1: a marker of mitochondrial damage and depletion in the liver during sepsis. Crit Care Med 2006; 34:2439-46. [PMID: 16791110 DOI: 10.1097/01.ccm.0000230240.02216.21] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Mitochondrial damage and dysfunction are thought to play an important role in the pathogenesis of sepsis-induced organ failures. Unfortunately, specific markers of mitochondrial damage in vital organs do not currently exist. Recently, carbomyl phosphate synthase (CPS)-1, a protein primarily localized to liver mitochondria, was found to be present in high concentrations in the plasma of septic humans. Thus, we hypothesized that the circulatory release of CPS-1 would correlate with mitochondrial damage or impaired mitochondrial function in the liver in a clinically relevant model of sepsis. DESIGN Prospective, randomized, controlled animal study. SETTING University medical center research laboratory. SUBJECTS Male, Balb/C mice, aged 10-12 wks. INTERVENTIONS Animals were assigned to receive cecal ligation and puncture (CLP sepsis) or sham operation and compared with untreated controls. Plasma CPS-1 levels and liver mitochondrial variables, including morphology, respiratory activity, mass (i.e., cardiolipin content), and protein carbonylation, were assessed at various time points (8, 24, and 48 hrs and 6 days) after surgery. MEASUREMENTS AND MAIN RESULTS Oxidant stress (i.e., carbonylation) was detected within 8 hrs of CLP and persisted through 48 hrs. Plasma CPS-1 levels increased dramatically at 24 hrs, remained significantly elevated at 48 hrs, and normalized by 6 days in the sepsis group. Abnormalities of liver mitochondrial morphology and function coincided with increased plasma CPS-1 levels. Mitochondrial depletion in the liver was not due to cell death but was associated with increased lysosomal clearance. Increased expression of mitochondrial biogenesis factors preceded restoration of mitochondrial variables and normalization of CPS-1 levels by day 6. CONCLUSIONS Circulating CPS-1 is a marker of mitochondrial damage and depletion in the liver during the subacute phase of CLP sepsis. From a mechanistic standpoint, mitochondrial depletion is not due to cell death but is apparently related to the removal of damaged mitochondria by lysosomes (i.e., autophagy), followed by repletion of mitochondrial populations. Further studies are needed to determine the clinical utility of CPS-1 as a marker of sepsis severity.
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Affiliation(s)
- Elliott D Crouser
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, The Ohio State University Medical Center, Columbus, 43210, USA.
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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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Chicco AJ, Sparagna GC. Role of cardiolipin alterations in mitochondrial dysfunction and disease. Am J Physiol Cell Physiol 2006; 292:C33-44. [PMID: 16899548 DOI: 10.1152/ajpcell.00243.2006] [Citation(s) in RCA: 453] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cardiolipin (CL) is a structurally unique dimeric phospholipid localized in the inner mitochondrial membrane where it is required for optimal mitochondrial function. In addition to its role in maintaining membrane potential and architecture, CL is known to provide essential structural and functional support to several proteins involved in mitochondrial bioenergetics. A loss of CL content, alterations in its acyl chain composition, and/or CL peroxidation have been associated with mitochondrial dysfunction in multiple tissues in a variety of pathological conditions, including ischemia, hypothyroidism, aging, and heart failure. Recently, aberrations in CL metabolism have been implicated as a primary causative factor in the cardioskeletal myopathy known as Barth syndrome, underscoring an important role of CL in human health and disease. The purpose of this review is to provide an overview of evidence that has linked changes in the CL profile to mitochondrial dysfunction in various pathological conditions. In addition, a brief overview of CL function and biosynthesis, and a discussion of methods used to examine CL in biological tissues are provided.
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Affiliation(s)
- Adam J Chicco
- Department of Integrative Physiology, University of Colorado at Boulder, Campus Box 354, Boulder, CO 80309-0354, USA
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Lesnefsky EJ, He D, Moghaddas S, Hoppel CL. Reversal of mitochondrial defects before ischemia protects the aged heart. FASEB J 2006; 20:1543-5. [PMID: 16793872 DOI: 10.1096/fj.05-4535fje] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Myocardial injury is increased in the aged heart during ischemia and reperfusion. Aging decreases oxidative metabolism in interfibrillar mitochondria (IFM) located between the myofibrils. We asked whether reversal of aging defects in IFM before ischemia would decrease injury in the aged heart following ischemia and reperfusion. Treatment with acetylcarnitine (AcCN) increases the activity of cytochrome oxidase in the aged heart. Aged (24 months) and adult (6 months) Fischer 344 rats were treated with AcCN (300 mg/kg i.p. 3 h before excision of the heart) or served as controls. AcCN restored oxidative phosphorylation and the activity of complexes III and IV in IFM from aged hearts to rates present in adults. Isolated hearts underwent 25 min global ischemia and 30 min reperfusion without additional treatment. Contractile recovery during reperfusion improved in hearts from AcCN-treated aged rats compared to aged controls and were similar to adults in recovery. AcCN-treated aged hearts sustained less damage, indicated by decreased lactate dehydrogenase (LDH) release during reperfusion. AcCN treatment did not alter functional recovery or LDH release in adults. Restoration of mitochondrial function in the aged heart before ischemia was accompanied by enhanced contractile recovery and decreased tissue injury following ischemia and reperfusion.
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Affiliation(s)
- Edward J Lesnefsky
- Department of Medicine (Division of Cardiology), Case Western Reserve University and Medical Service, Cleveland, Ohio, USA.
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Chen Q, Hoppel CL, Lesnefsky EJ. Blockade of electron transport before cardiac ischemia with the reversible inhibitor amobarbital protects rat heart mitochondria. J Pharmacol Exp Ther 2005; 316:200-7. [PMID: 16174799 DOI: 10.1124/jpet.105.091702] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cardiac ischemia damages the mitochondrial electron transport chain. Irreversible blockade of electron transport at complex I by rotenone decreases ischemic damage to cardiac mitochondria by decreasing the loss of cytochrome c and preserving respiration through cytochrome oxidase. Therapeutic intervention to protect myocardium during ischemia and reperfusion requires the use of a reversible inhibitor that allows resumption of oxidative metabolism during reperfusion. Amobarbital is a reversible inhibitor at the rotenone site of complex I. We asked whether amobarbital administered immediately before ischemia protected respiratory function. Isolated rat hearts were perfused for 15 min followed by 25-min global ischemia at 37 degrees C. Amobarbital-treated hearts received drug for 1 min before ischemia. Subsarcolemmal (SSM) and interfibrillar (IFM) populations of mitochondria were isolated after ischemia, and oxidative phosphorylation was measured. Amobarbital protected oxidative phosphorylation, including through cytochrome oxidase, in both SSM and IFM in a dose-dependent manner, with an optimal dose of 2 to 2.5 mM. Amobarbital also preserved cytochrome c content in both SSM and IFM. Thus, reversible blockade of the electron transport chain during ischemia protects mitochondrial respiration.
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Affiliation(s)
- Qun Chen
- Dept. of Medicine, Cardiology Section, Medical Service 111(W), Case Western Reserve University, Louis Stokes Veterans Affairs Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA.
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