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Issop L, Rone MB, Papadopoulos V. Organelle plasticity and interactions in cholesterol transport and steroid biosynthesis. Mol Cell Endocrinol 2013; 371:34-46. [PMID: 23246788 DOI: 10.1016/j.mce.2012.12.003] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 12/04/2012] [Accepted: 12/04/2012] [Indexed: 12/20/2022]
Abstract
Steroid biosynthesis is a multi-step process controlled by pituitary hormones, which, via cAMP-dependent signaling pathways, drive tissue-specific steroid formation. Steroidogenesis begins with the transport of the substrate, cholesterol, from intracellular stores into the inner mitochondrial membrane, where the steroidogenic enzyme CYP11A1 converts cholesterol to pregnenolone. This process is accelerated by hormones and involves a number of proteins and protein-protein interactions. Indeed, cholesterol, stored in lipid droplets and membranes, is transferred through a hormone-induced complex of proteins derived from the cytosol, mitochondria, and other organelles termed the transduceosome to the outer mitochondrial membrane. From there, cholesterol reaches CYP11A1 through outer/inner membrane contact sites. Thus, cholesterol transfer is likely achieved through a hormone-dependent reorganization of organelles and protein distribution and interactions. The findings reviewed herein suggest the presence of a hormone-dependent organelle communication network mediated by protein-protein interactions and inter-organelle trafficking, resulting in the efficient and timely delivery of cholesterol into mitochondria for steroid synthesis.
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Affiliation(s)
- Leeyah Issop
- Research Institute of the McGill University Health Centre, Department of Medicine, McGill University, Montreal, Quebec, Canada H3G 1A4
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52
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Bernardi P. The mitochondrial permeability transition pore: a mystery solved? Front Physiol 2013; 4:95. [PMID: 23675351 PMCID: PMC3650560 DOI: 10.3389/fphys.2013.00095] [Citation(s) in RCA: 255] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 04/19/2013] [Indexed: 01/04/2023] Open
Abstract
The permeability transition (PT) denotes an increase of the mitochondrial inner membrane permeability to solutes with molecular masses up to about 1500 Da. It is presumed to be mediated by opening of a channel, the permeability transition pore (PTP), whose molecular nature remains a mystery. Here I briefly review the history of the PTP, discuss existing models, and present our new results indicating that reconstituted dimers of the FOF1 ATP synthase form a channel with properties identical to those of the mitochondrial megachannel (MMC), the electrophysiological equivalent of the PTP. Open questions remain, but there is now promise that the PTP can be studied by genetic methods to solve the large number of outstanding problems.
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Affiliation(s)
- Paolo Bernardi
- Department of Biomedical Sciences, University of Padova Padova, Italy
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53
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Effects of 18-kDa translocator protein knockdown on gene expression of glutamate receptors, transporters, and metabolism, and on cell viability affected by glutamate. Pharmacogenet Genomics 2012; 22:606-19. [PMID: 22732722 DOI: 10.1097/fpc.0b013e3283544531] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Previously, several important roles for glutamate have been described for the biology of primary brain tumors. For example, glutamate has been suggested to promote glioma cell proliferation by the activation of the 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid (AMPA) subtype of glutamate receptors. In the present study, we determined the potential regulatory roles of the 18-kDa translocator protein (TSPO) in the glutamatergic system in relation to cell death of brain tumor cells through knockdown of the TSPO by genetic manipulation. MATERIALS AND METHODS With microarray analysis and validation of gene expression of particular genes using real-time PCR, we found effects because of small inhibitory RNA knockdown of the TSPO in human U118MG glioblastoma cells on gene expression of glutamate receptors, glutamate transporters, and enzymes for glutamate metabolism. We also applied antisense RNA to silence TSPO in rat C6 glioblastoma cells and assayed the effects on DNA fragmentation, indicative of apoptosis, because of glutamate exposure. RESULTS In particular, the effects of TSPO silencing in human U118MG cells related to glutamate metabolism indicate a net effect of a reduction in glutamate levels, which may potentially protect the cells in question from cell death. The TSPO knockdown in C6 cells showed that TSPO is required for the induction of apoptosis because of glutamate exposure. CONCLUSION These findings show that interactions between the TSPO and the glutamatergic system may play a role in tumor development of glioblastoma cells. This may also have implications for our understanding of the involvement of the TSPO in secondary brain damage and neurodegenerative diseases.
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Asemu G, O'Connell KA, Cox JW, Dabkowski ER, Xu W, Ribeiro RF, Shekar KC, Hecker PA, Rastogi S, Sabbah HN, Hoppel CL, Stanley WC. Enhanced resistance to permeability transition in interfibrillar cardiac mitochondria in dogs: effects of aging and long-term aldosterone infusion. Am J Physiol Heart Circ Physiol 2012; 304:H514-28. [PMID: 23241318 DOI: 10.1152/ajpheart.00674.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Functional differences between subsarcolemmal and interfibrillar cardiac mitochondria (SSM and IFM) have been observed with aging and pathological conditions in rodents. Results are contradictory, and there is little information from large animal models. We assessed the respiratory function and resistance to mitochondrial permeability transition (MPT) in SSM and IFM from healthy young (1 yr) and old (8 yr) female beagles and in old beagles with hypertension and left ventricular (LV) wall thickening induced by 16 wk of aldosterone infusion. MPT was assessed in SSM and IFM by Ca(2+) retention and swelling. Healthy young and old beagles had similar mitochondrial structure, respiratory function, and Ca(2+)-induced MPT within SSM and IFM subpopulations. On the other hand, oxidative capacity and resistance to Ca(2+)-induced MPT were significantly greater in IFM compared with SSM in all groups. Old beagles treated with aldosterone had greater LV wall thickness and worse diastolic filling but normal LV chamber volume and systolic function. Treatment with aldosterone did not alter mitochondrial respiratory function but accelerated Ca(2+)-induced MPT in SSM, but not IFM, compared with healthy old and young beagles. In conclusion, in a large animal model, oxidative capacity and resistance to MPT were greater in IFM than in SSM. Furthermore, aldosterone infusion increased susceptibility to MPT in SSM, but not IFM. Together this suggests that SSM are less resilient to acute stress than IFM in the healthy heart and are more susceptible to the development of pathology with chronic stress.
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Affiliation(s)
- Girma Asemu
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, MD, USA
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55
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Translocator protein (18 kDa): a promising therapeutic target and diagnostic tool for cardiovascular diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:162934. [PMID: 23251719 PMCID: PMC3516045 DOI: 10.1155/2012/162934] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 10/22/2012] [Accepted: 11/04/2012] [Indexed: 01/15/2023]
Abstract
The translocator protein (18 kDa) (TSPO) is a five transmembrane domain protein in mitochondria, abundantly expressed in a variety of organs and tissues. TSPO contributes to a wide range of biological processes, including cholesterol transportation, mitochondrial membrane potential and respiratory chain regulation, apoptosis, and oxidative stress. Recent studies have demonstrated that TSPO might also be involved in the physiological regulation of cardiac chronotropy and inotropy. Accordingly, TSPO ligands play significant roles in protecting the cardiovascular systems under pathological conditions through cardiac electrical activity retention, intracellular calcium maintenance, mitochondrial energy provision, mitochondrial membrane potential equilibrium, and reactive oxygen species inhibition. This paper focuses on the physiological and pathological characteristics of TSPO in the cardiovascular systems and also summarizes the properties of TSPO ligands. TSPO represents a potential therapeutic target and diagnostic tool for cardiovascular diseases including arrhythmia, myocardial infarction, cardiac hypertrophy, atherosclerosis, myocarditis, and large vessel vasculitis.
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56
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The mitochondrial permeability transition pore (PTP) — An example of multiple molecular exaptation? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:2072-86. [DOI: 10.1016/j.bbabio.2012.06.620] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 06/19/2012] [Accepted: 06/21/2012] [Indexed: 11/21/2022]
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Korde AS, Maragos WF. Identification of an N-methyl-D-aspartate receptor in isolated nervous system mitochondria. J Biol Chem 2012; 287:35192-35200. [PMID: 22918829 DOI: 10.1074/jbc.m111.322032] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
NMDA ionotropic glutamate receptors gate the cytoplasmic influx of calcium, which may, depending on the intensity of the stimulus, subserve either normal synaptic communication or cell death. We demonstrate that when isolated mitochondria are exposed to calcium and NMDA agonists, there is a significant increase in mitochondrial calcium levels. The agonist/antagonist response studies on purified mitochondria suggest the presence of a receptor on mitochondria with features similar to plasma membrane NMDA receptors. Immunogold electron microscopy of hippocampal tissue sections revealed extensive localization of NR2a subunit immunoreactivity on mitochondria. Transient transfection of neuronal GT1-7 cells with an NR1-NR2a NMDA receptor subunit cassette specifically targeting mitochondria resulted in a significant increase in mitochondrial calcium and neuroprotection against glutamate-induced cell death. Mitochondria prepared from GT1-7 cells in which the NR1 subunit of NMDA receptors was silenced demonstrated a decrease in calcium uptake. Our findings are the first to demonstrate that mitochondria express a calcium transport protein that shares characteristics with the NMDA receptor and may play a neuroprotective role.
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Affiliation(s)
- Amit S Korde
- Neurology Service, Hunter Holmes McGuire Veterans Hospital, Richmond, Virginia 23249
| | - William F Maragos
- Neurology Service, Hunter Holmes McGuire Veterans Hospital, Richmond, Virginia 23249; Department of Neurology, Virginia Commonwealth University, Richmond, Virginia 23298.
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58
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Seidlmayer LK, Gomez-Garcia MR, Blatter LA, Pavlov E, Dedkova EN. Inorganic polyphosphate is a potent activator of the mitochondrial permeability transition pore in cardiac myocytes. ACTA ACUST UNITED AC 2012; 139:321-31. [PMID: 22547663 PMCID: PMC3343371 DOI: 10.1085/jgp.201210788] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mitochondrial dysfunction caused by excessive Ca2+ accumulation is a major contributor to cardiac cell and tissue damage during myocardial infarction and ischemia–reperfusion injury (IRI). At the molecular level, mitochondrial dysfunction is induced by Ca2+-dependent opening of the mitochondrial permeability transition pore (mPTP) in the inner mitochondrial membrane, which leads to the dissipation of mitochondrial membrane potential (ΔΨm), disruption of adenosine triphosphate production, and ultimately cell death. Although the role of Ca2+ for induction of mPTP opening is established, the exact molecular mechanism of this process is not understood. The aim of the present study was to test the hypothesis that the adverse effect of mitochondrial Ca2+ accumulation is mediated by its interaction with inorganic polyphosphate (polyP), a polymer of orthophosphates linked by phosphoanhydride bonds. We found that cardiac mitochondria contained significant amounts (280 ± 60 pmol/mg of protein) of short-chain polyP with an average length of 25 orthophosphates. To test the role of polyP for mPTP activity, we investigated kinetics of Ca2+ uptake and release, ΔΨm and Ca2+-induced mPTP opening in polyP-depleted mitochondria. polyP depletion was achieved by mitochondria-targeted expression of a polyP-hydrolyzing enzyme. Depletion of polyP in mitochondria of rabbit ventricular myocytes led to significant inhibition of mPTP opening without affecting mitochondrial Ca2+ concentration by itself. This effect was observed when mitochondrial Ca2+ uptake was stimulated by increasing cytosolic [Ca2+] in permeabilized myocytes mimicking mitochondrial Ca2+ overload observed during IRI. Our findings suggest that inorganic polyP is a previously unrecognized major activator of mPTP. We propose that the adverse effect of polyphosphate might be caused by its ability to form stable complexes with Ca2+ and directly contribute to inner mitochondrial membrane permeabilization.
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Affiliation(s)
- Lea K Seidlmayer
- Department of Molecular Physiology and Biophysics, Rush University Medical Center, Chicago, IL 60612, USA
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59
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Sheu SS, Dirksen RT, Pugh EN. The 65th Symposium of the Society for General Physiologists: energizing research in mitochondrial physiology and medicine. ACTA ACUST UNITED AC 2012; 138:563-7. [PMID: 22124113 PMCID: PMC3226972 DOI: 10.1085/jgp.201110739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Shey-Shing Sheu
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA 19010, USA
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60
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Inhibition of the Mitochondrial Permeability Transition for Cytoprotection: Direct versus Indirect Mechanisms. Biochem Res Int 2012; 2012:213403. [PMID: 22675634 PMCID: PMC3364550 DOI: 10.1155/2012/213403] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 02/07/2012] [Indexed: 11/17/2022] Open
Abstract
Mitochondria are fascinating organelles, which fulfill multiple cellular functions, as diverse as energy production, fatty acid β oxidation, reactive oxygen species (ROS) production and detoxification, and cell death regulation. The coordination of these functions relies on autonomous mitochondrial processes as well as on sustained cross-talk with other organelles and/or the cytosol. Therefore, this implies a tight regulation of mitochondrial functions to ensure cell homeostasis. In many diseases (e.g., cancer, cardiopathies, nonalcoholic fatty liver diseases, and neurodegenerative diseases), mitochondria can receive harmful signals, dysfunction and then, participate to pathogenesis. They can undergo either a decrease of their bioenergetic function or a process called mitochondrial permeability transition (MPT) that can coordinate cell death execution. Many studies present evidence that protection of mitochondria limits disease progression and severity. Here, we will review recent strategies to preserve mitochondrial functions via direct or indirect mechanisms of MPT inhibition. Thus, several mitochondrial proteins may be considered for cytoprotective-targeted therapies.
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61
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Calì T, Ottolini D, Brini M. Mitochondrial Ca(2+) and neurodegeneration. Cell Calcium 2012; 52:73-85. [PMID: 22608276 PMCID: PMC3396847 DOI: 10.1016/j.ceca.2012.04.015] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 04/18/2012] [Accepted: 04/20/2012] [Indexed: 12/16/2022]
Abstract
Mitochondria are essential for ensuring numerous fundamental physiological processes such as cellular energy, redox balance, modulation of Ca2+ signaling and important biosynthetic pathways. They also govern the cell fate by participating in the apoptosis pathway. The mitochondrial shape, volume, number and distribution within the cells are strictly controlled. The regulation of these parameters has an impact on mitochondrial function, especially in the central nervous system, where trafficking of mitochondria is critical to their strategic intracellular distribution, presumably according to local energy demands. Thus, the maintenance of a healthy mitochondrial population is essential to avoid the impairment of the processes they regulate: for this purpose, cells have developed mechanisms involving a complex system of quality control to remove damaged mitochondria, or to renew them. Defects of these processes impair mitochondrial function and lead to disordered cell function, i.e., to a disease condition. Given the standard role of mitochondria in all cells, it might be expected that their dysfunction would give rise to similar defects in all tissues. However, damaged mitochondrial function has pleiotropic effects in multicellular organisms, resulting in diverse pathological conditions, ranging from cardiac and brain ischemia, to skeletal muscle myopathies to neurodegenerative diseases. In this review, we will focus on the relationship between mitochondrial (and cellular) derangements and Ca2+ dysregulation in neurodegenerative diseases, emphasizing the evidence obtained in genetic models. Common patterns, that recognize the derangement of Ca2+ and energy control as a causative factor, have been identified: advances in the understanding of the molecular regulation of Ca2+ homeostasis, and on the ways in which it could become perturbed in neurological disorders, may lead to the development of therapeutic strategies that modulate neuronal Ca2+ signaling.
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Affiliation(s)
- Tito Calì
- Department of Comparative Biomedicine and Food Science, University of Padova, Padova, Italy
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62
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Eckert GP, Renner K, Eckert SH, Eckmann J, Hagl S, Abdel-Kader RM, Kurz C, Leuner K, Muller WE. Mitochondrial Dysfunction—A Pharmacological Target in Alzheimer's Disease. Mol Neurobiol 2012; 46:136-50. [DOI: 10.1007/s12035-012-8271-z] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Accepted: 04/16/2012] [Indexed: 12/12/2022]
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63
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Bensassi F, Gallerne C, Sharaf El Dein O, Lemaire C, Hajlaoui MR, Bacha H. Involvement of mitochondria-mediated apoptosis in deoxynivalenol cytotoxicity. Food Chem Toxicol 2012; 50:1680-9. [DOI: 10.1016/j.fct.2012.01.015] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 01/05/2012] [Accepted: 01/10/2012] [Indexed: 10/14/2022]
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Wiederkehr A, Wollheim CB. Mitochondrial signals drive insulin secretion in the pancreatic β-cell. Mol Cell Endocrinol 2012; 353:128-37. [PMID: 21784130 DOI: 10.1016/j.mce.2011.07.016] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 07/07/2011] [Indexed: 12/31/2022]
Abstract
β-Cell nutrient sensing depends on mitochondrial function. Oxidation of nutrient-derived metabolites in the mitochondria leads to plasma membrane depolarization, Ca(2+) influx and insulin granule exocytosis. Subsequent mitochondrial Ca(2+) uptake further accelerates metabolism and oxidative phosphorylation. Nutrient activation also increases the mitochondrial matrix pH. This alkalinization is required to maintain elevated insulin secretion during prolonged nutrient stimulation. Together the mitochondrial Ca(2+) rise and matrix alkalinization assure optimal ATP synthesis necessary for efficient activation of the triggering pathway of insulin secretion. The sustained, amplifying pathway of insulin release also depends on mitochondrial Ca(2+) signals, which likely influence the generation of glucose-derived metabolites serving as coupling factors. Therefore, mitochondria are both recipients and generators of signals essential for metabolism-secretion coupling. Activation of these signaling pathways would be an attractive target for the improvement of β-cell function and the treatment of type 2 diabetes.
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65
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The bad, the good, and the ugly about oxidative stress. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:163913. [PMID: 22619696 PMCID: PMC3350994 DOI: 10.1155/2012/163913] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 01/16/2012] [Accepted: 02/07/2012] [Indexed: 01/07/2023]
Abstract
Alzheimer's disease (AD), Parkinson's disease (PD), and cancer (e.g., leukemia) are the most devastating disorders affecting millions of people worldwide. Except for some kind of cancers, no effective and/or definitive therapeutic treatment aimed to reduce or to retard the clinic and pathologic symptoms induced by AD and PD is presently available. Therefore, it is urgently needed to understand the molecular basis of these disorders. Since oxidative stress (OS) is an important etiologic factor of the pathologic process of AD, PD, and cancer, understanding how intracellular signaling pathways respond to OS will have a significant implication in the therapy of these diseases. Here, we propose a model of minimal completeness of cell death signaling induced by OS as a mechanistic explanation of neuronal and cancer cell demise. This mechanism might provide the basis for therapeutic design strategies. Finally, we will attempt to associate PD, cancer, and OS. This paper critically analyzes the evidence that support the “oxidative stress model” in neurodegeneration and cancer.
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66
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Khairallah RJ, Kim J, O'Shea KM, O'Connell KA, Brown BH, Galvao T, Daneault C, Rosiers CD, Polster BM, Hoppel CL, Stanley WC. Improved mitochondrial function with diet-induced increase in either docosahexaenoic acid or arachidonic acid in membrane phospholipids. PLoS One 2012; 7:e34402. [PMID: 22479624 PMCID: PMC3316678 DOI: 10.1371/journal.pone.0034402] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 02/27/2012] [Indexed: 01/11/2023] Open
Abstract
Mitochondria can depolarize and trigger cell death through the opening of the mitochondrial permeability transition pore (MPTP). We recently showed that an increase in the long chain n3 polyunsaturated fatty acids (PUFA) docosahexaenoic acid (DHA; 22:6n3) and depletion of the n6 PUFA arachidonic acid (ARA; 20:4n6) in mitochondrial membranes is associated with a greater Ca2+ load required to induce MPTP opening. Here we manipulated mitochondrial phospholipid composition by supplementing the diet with DHA, ARA or combined DHA+ARA in rats for 10 weeks. There were no effects on cardiac function, or respiration of isolated mitochondria. Analysis of mitochondrial phospholipids showed DHA supplementation increased DHA and displaced ARA in mitochondrial membranes, while supplementation with ARA or DHA+ARA increased ARA and depleted linoleic acid (18:2n6). Phospholipid analysis revealed a similar pattern, particularly in cardiolipin. Tetralinoleoyl cardiolipin was depleted by 80% with ARA or DHA+ARA supplementation, with linoleic acid side chains replaced by ARA. Both the DHA and ARA groups had delayed Ca2+-induced MPTP opening, but the DHA+ARA group was similar to the control diet. In conclusion, alterations in mitochondria membrane phospholipid fatty acid composition caused by dietary DHA or ARA was associated with a greater cumulative Ca2+ load required to induced MPTP opening. Further, high levels of tetralinoleoyl cardiolipin were not essential for normal mitochondrial function if replaced with very-long chain n3 or n6 PUFAs.
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Affiliation(s)
- Ramzi J. Khairallah
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Junhwan Kim
- Department of Medicine and Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Karen M. O'Shea
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Kelly A. O'Connell
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Bethany H. Brown
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Tatiana Galvao
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Caroline Daneault
- Department of Nutrition and Montreal Heart Institute, Université de Montréal, Montreal, Quebecc, Canada
| | - Christine Des Rosiers
- Department of Nutrition and Montreal Heart Institute, Université de Montréal, Montreal, Quebecc, Canada
| | - Brian M. Polster
- Department of Anesthesiology, and Shock, Trauma, and the Anesthesiology Research (STAR) Center, University of Maryland, Baltimore, Maryland, United States of America
| | - Charles L. Hoppel
- Department of Medicine and Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - William C. Stanley
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, Maryland, United States of America
- * E-mail:
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Grattagliano I, de Bari O, Bernardo TC, Oliveira PJ, Wang DQH, Portincasa P. Role of mitochondria in nonalcoholic fatty liver disease--from origin to propagation. Clin Biochem 2012; 45:610-8. [PMID: 22484459 DOI: 10.1016/j.clinbiochem.2012.03.024] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2011] [Revised: 02/02/2012] [Accepted: 03/12/2012] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Mitochondria play a major role in cell energy-generating processes and integrate several signalling pathways to control cellular life and death. DESIGN AND METHODS Several liver diseases are characterized by mitochondrial alterations which are directly or indirectly dependent on the activation of intracellular stress cascades or receptor-mediated pathways. This article examines the role of mitochondrial dysfunction in critical initiating or propagating events in fatty liver infiltration and nonalcoholic fatty liver disease (NAFLD). Genetic variants and the role of drug-induced toxicity have been considered. RESULTS Key alterations of mitochondrial physiology associated with hepatocyte fatty changes are described. The value of novel non-invasive diagnostic methods to detect mitochondrial metabolic alterations is also discussed. CONCLUSIONS Mitochondrial metabolic remodeling is a predominant factor in the appearance and perpetuation of hepatocyte fat accumulation. Non-invasive techniques to identify mitochondrial dysfunction and proper mitochondria protection are two necessary clinical steps for an efficient management of NAFLD.
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Affiliation(s)
- Ignazio Grattagliano
- Department of Interdisciplinary Medicine, Clinica Medica A. Murri, University of Bari Medical School, Bari, Italy.
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68
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Gukovsky I, Pandol SJ, Mareninova OA, Shalbueva N, Jia W, Gukovskaya AS. Impaired autophagy and organellar dysfunction in pancreatitis. J Gastroenterol Hepatol 2012; 27 Suppl 2:27-32. [PMID: 22320913 PMCID: PMC3281514 DOI: 10.1111/j.1440-1746.2011.07004.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Recent findings from our group, obtained on experimental in vivo and ex vivo models of pancreatitis, reveal that this disease causes a profound dysfunction of key cellular organelles, lysosomes and mitochondria. We found that autophagy, the main cellular degradative, lysosome-driven process, is activated but also impaired in acute pancreatitis because of its' inefficient progression/resolution (flux) resulting from defective function of lysosomes. One mechanism underlying the lysosomal dysfunction in pancreatitis is abnormal processing (maturation) and activation of cathepsins, major lysosomal hydrolases; another is a decrease in pancreatic levels of key lysosomal membrane proteins LAMP-1 and LAMP-2. Our data indicate that lysosomal dysfunction plays an important initiating role in pancreatitis pathobiology. The impaired autophagy mediates vacuole accumulation in acinar cells; furthermore, the abnormal maturation and activation of cathepsins leads to increase in intra-acinar trypsin, the hallmark of pancreatitis; and LAMP-2 deficiency causes inflammation and acinar cell necrosis. Thus, the autophagic and lysosomal dysfunctions mediate key pathologic responses of pancreatitis. On the other hand, we showed that pancreatitis causes acinar cell mitochondria depolarization, mediated by the permeability transition pore (PTP). Genetic (via deletion of cyclophilin D) inactivation of PTP prevents mitochondrial depolarization and greatly ameliorates the pathologic responses of pancreatitis. Further, our data suggest that mitochondrial damage, by stimulating autophagy, increases the demand for efficient lysosomal degradation and therefore aggravates the pathologic consequences of lysosomal dysfunction. Thus, the combined autophagic, lysosomal and mitochondrial dysfunctions are key to the pathogenesis of pancreatitis.
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Affiliation(s)
- Ilya Gukovsky
- Southern California Research Centers for Alcoholic Liver and Pancreatic Diseases and Cirrhosis, VA Greater Los Angeles Healthcare System, and University of California at Los Angeles, California 90073, USA
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69
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Stanley WC, Khairallah RJ, Dabkowski ER. Update on lipids and mitochondrial function: impact of dietary n-3 polyunsaturated fatty acids. Curr Opin Clin Nutr Metab Care 2012; 15:122-6. [PMID: 22248591 PMCID: PMC4067133 DOI: 10.1097/mco.0b013e32834fdaf7] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Recent evidence has linked n-3 polyunsaturated fatty acid (PUFA) supplementation with dramatic alterations of mitochondrial phospholipid membranes and favorable changes in mitochondrial function. In the present review, we examine the novel effects of n-3 PUFA on mitochondria, with an emphasis on cardiac mitochondrial phospholipids. RECENT FINDINGS There is growing evidence that dietary n-3 PUFA, particularly docosahexaenoic acid (DHA), has profound effects on mitochondrial membrane phospholipid composition and mitochondrial function. Supplementation with n-3 PUFA increases membrane phospholipid DHA and depletes arachidonic acid, and can increase cardiolipin, a tetra-acyl phospholipid that is unique to mitochondrial and essential for optimal mitochondrial function. Recent studies show that supplementation with DHA decreases propensity for cardiac mitochondria to undergo permeability transition, a catastrophic event often leading to cell death. This finding provides a potential mechanism for the cardioprotective effect of DHA. Interestingly, other n-3 PUFAs that modify membrane composition to a lesser extent have substantially less of an effect on mitochondria and do not appear to directly protect the heart. SUMMARY Current data support a role for n-3 PUFA supplementation, particularly DHA, on mitochondria that are strongly associated with changes in mitochondrial phospholipid composition.
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Affiliation(s)
- William C Stanley
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, Maryland 21201, USA.
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Demaison L, Moreau D, Clauw F, Vergely C, Rochette L. Mitochondrial basis of the anti-arrhythmic action of lidocaine and modulation by the n-6 to n-3 PUFA ratio of cardiac phospholipids. Fundam Clin Pharmacol 2012; 27:373-86. [PMID: 22360894 DOI: 10.1111/j.1472-8206.2012.01031.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aim of this study was to evaluate the involvement of mitochondria in the mechanism of the anti-arrhythmic lidocaine. Rats were fed with a diet containing either n-6 polyunsaturated fatty acids (PUFAs, SSO group) or an equimolecular mixture of n-3 and n-6 PUFAs (FO group) for 8 weeks. The hearts were perfused according to the working mode using a medium with or without lidocaine 5 μm. They were then subjected to local ischemia (20 min) and reperfusion (30 min). Dietary n-3 PUFAs triggered the expected decrease in the n-6/n-3 PUFA ratio of cardiac phospholipids. Reperfusing the ischemic area favored the incidence of severe arrhythmias. Lidocaine treatment abolished almost completely reperfusion arrhythmias in the FO group, but did not display anti-arrhythmic properties in the SSO group. As it was indicated by measurements of the mitochondrial function, lidocaine seemed to favor mitochondrial calcium retention in the FO group, which might prevent cytosolic calcium spikes and reperfusion arrhythmias. In the SSO group, the resistance to lidocaine was associated with an aggravation of cellular damages. The mitochondrial calcium retention capacities were saturated, and lidocaine was unable to increase them, making the drug inefficient in preventing reperfusion arrhythmias.
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Affiliation(s)
- Luc Demaison
- INRA, Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France.
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Lenaz G, Genova ML. Supramolecular Organisation of the Mitochondrial Respiratory Chain: A New Challenge for the Mechanism and Control of Oxidative Phosphorylation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:107-44. [DOI: 10.1007/978-1-4614-3573-0_5] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Bensassi F, Gallerne C, dein OSE, Hajlaoui MR, Bacha H, Lemaire C. Mechanism of Alternariol monomethyl ether-induced mitochondrial apoptosis in human colon carcinoma cells. Toxicology 2011; 290:230-40. [DOI: 10.1016/j.tox.2011.09.087] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 09/28/2011] [Accepted: 09/30/2011] [Indexed: 10/16/2022]
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Zulian A, Sileikytė J, Petronilli V, Bova S, Dabbeni-Sala F, Cargnelli G, Rennison D, Brimble MA, Hopkins B, Bernardi P, Ricchelli F. The translocator protein (peripheral benzodiazepine receptor) mediates rat-selective activation of the mitochondrial permeability transition by norbormide. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:1600-5. [PMID: 21889488 DOI: 10.1016/j.bbabio.2011.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 07/29/2011] [Accepted: 08/10/2011] [Indexed: 11/30/2022]
Abstract
We have investigated the mechanism of rat-selective induction of the mitochondrial permeability transition (PT) by norbormide (NRB). We show that the inducing effect of NRB on the PT (i) is inhibited by the selective ligands of the 18kDa outer membrane (OMM) translocator protein (TSPO, formerly peripheral benzodiazepine receptor) protoporphyrin IX, N,N-dihexyl-2-(4-fluorophenyl)indole-3-acetamide and 7-chloro-5-(4-chlorophenyl)-1,3-dihydro-1-methyl-2H-1,4-benzodiazepin-2-one; and (ii) is lost in digitonin mitoplasts, which lack an intact OMM. In mitoplasts the PT can still be induced by the NRB cationic derivative OL14, which contrary to NRB is also effective in intact mitochondria from mouse and guinea pig. We conclude that selective NRB transport into rat mitochondria occurs via TSPO in the OMM, which allows its translocation to PT-regulating sites in the inner membrane. Thus, species-specificity of NRB toward the rat PT depends on subtle differences in the structure of TSPO or of TSPO-associated proteins affecting its substrate specificity.
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Affiliation(s)
- Alessandra Zulian
- C.N.R. Institute of Neurosciences at the Department of Biomedical Sciences, University of Padova, Italy
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