1
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Ponnusamy T, Velusamy P, Shanmughapriya S. Mrs2-mediated mitochondrial magnesium uptake is essential for the regulation of MCU-mediated mitochondrial Ca 2+ uptake and viability. Mitochondrion 2024; 76:101877. [PMID: 38599304 DOI: 10.1016/j.mito.2024.101877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 03/07/2024] [Accepted: 04/07/2024] [Indexed: 04/12/2024]
Abstract
Mitochondrial Ca2+ uptake is essential in regulating bioenergetics, cell death, and cytosolic Ca2+ transients. Mitochondrial Calcium Uniporter (MCU) mediates the mitochondrial Ca2+ uptake. Though MCU regulation by MICUs is unequivocally established, there needs to be more knowledge of whether divalent cations regulate MCU. Here, we set out to understand the mitochondrial matrix Mg2+-dependent regulation of MCU activity. We showed that decreased matrix [Mg2+] is associated with increased MCU activity and significantly prompted mitochondrial permeability transition pore opening. Our findings support the critical role of mMg2+ in regulating MCU activity.
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Affiliation(s)
- Thiruvelselvan Ponnusamy
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Prema Velusamy
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Santhanam Shanmughapriya
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA.
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2
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Trinchese G, Cimmino F, Catapano A, Cavaliere G, Mollica MP. Mitochondria: the gatekeepers between metabolism and immunity. Front Immunol 2024; 15:1334006. [PMID: 38464536 PMCID: PMC10920337 DOI: 10.3389/fimmu.2024.1334006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 02/08/2024] [Indexed: 03/12/2024] Open
Abstract
Metabolism and immunity are crucial monitors of the whole-body homeodynamics. All cells require energy to perform their basic functions. One of the most important metabolic skills of the cell is the ability to optimally adapt metabolism according to demand or availability, known as metabolic flexibility. The immune cells, first line of host defense that circulate in the body and migrate between tissues, need to function also in environments in which nutrients are not always available. The resilience of immune cells consists precisely in their high adaptive capacity, a challenge that arises especially in the framework of sustained immune responses. Pubmed and Scopus databases were consulted to construct the extensive background explored in this review, from the Kennedy and Lehninger studies on mitochondrial biochemistry of the 1950s to the most recent findings on immunometabolism. In detail, we first focus on how metabolic reconfiguration influences the action steps of the immune system and modulates immune cell fate and function. Then, we highlighted the evidence for considering mitochondria, besides conventional cellular energy suppliers, as the powerhouses of immunometabolism. Finally, we explored the main immunometabolic hubs in the organism emphasizing in them the reciprocal impact between metabolic and immune components in both physiological and pathological conditions.
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Affiliation(s)
| | - Fabiano Cimmino
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Angela Catapano
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Gina Cavaliere
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Maria Pina Mollica
- Department of Biology, University of Naples Federico II, Naples, Italy
- Task Force on Microbiome Studies, University of Naples Federico II, Naples, Italy
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3
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Mitochondrial Ca 2+ regulation in the etiology of heart failure: physiological and pathophysiological implications. Acta Pharmacol Sin 2020; 41:1301-1309. [PMID: 32694759 PMCID: PMC7608470 DOI: 10.1038/s41401-020-0476-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/04/2020] [Accepted: 07/06/2020] [Indexed: 12/14/2022] Open
Abstract
Heart failure (HF) represents one of the leading causes of cardiovascular diseases with high rates of hospitalization, morbidity and mortality worldwide. Ample evidence has consolidated a crucial role for mitochondrial injury in the progression of HF. It is well established that mitochondrial Ca2+ participates in the regulation of a wide variety of biological processes, including oxidative phosphorylation, ATP synthesis, reactive oxygen species (ROS) generation, mitochondrial dynamics and mitophagy. Nonetheless, mitochondrial Ca2+ overload stimulates mitochondrial permeability transition pore (mPTP) opening and mitochondrial swelling, resulting in mitochondrial injury, apoptosis, cardiac remodeling, and ultimately development of HF. Moreover, mitochondria possess a series of Ca2+ transport influx and efflux channels, to buffer Ca2+ in the cytoplasm. Interaction at mitochondria-associated endoplasmic reticulum membranes (MAMs) may also participate in the regulation of mitochondrial Ca2+ homeostasis and plays an essential role in the progression of HF. Here, we provide an overview of regulation of mitochondrial Ca2+ homeostasis in maintenance of cardiac function, in an effort to identify novel therapeutic strategies for the management of HF.
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4
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The Role of Reactive Oxygen Species in the Life Cycle of the Mitochondrion. Int J Mol Sci 2020; 21:ijms21062173. [PMID: 32245255 PMCID: PMC7139706 DOI: 10.3390/ijms21062173] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/12/2020] [Accepted: 03/19/2020] [Indexed: 02/07/2023] Open
Abstract
Currently, it is known that, in living systems, free radicals and other reactive oxygen and nitrogen species play a double role, because they can cause oxidative damage and tissue dysfunction and serve as molecular signals activating stress responses that are beneficial to the organism. It is also known that mitochondria, because of their capacity to produce free radicals, play a major role in tissue oxidative damage and dysfunction and provide protection against excessive tissue dysfunction through several mechanisms, including the stimulation of permeability transition pore opening. This process leads to mitoptosis and mitophagy, two sequential processes that are a universal route of elimination of dysfunctional mitochondria and is essential to protect cells from the harm due to mitochondrial disordered metabolism. To date, there is significant evidence not only that the above processes are induced by enhanced reactive oxygen species (ROS) production, but also that such production is involved in the other phases of the mitochondrial life cycle. Accumulating evidence also suggests that these effects are mediated through the regulation of the expression and the activity of proteins that are engaged in processes such as genesis, fission, fusion, and removal of mitochondria. This review provides an account of the developments of the knowledge on the dynamics of the mitochondrial population, examining the mechanisms governing their genesis, life, and death, and elucidating the role played by free radicals in such processes.
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5
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Abstract
Mitochondria are the source of damage-associated molecular patterns (DAMPs), which are molecules that play a key modulatory role in immune cells. These molecules include proteins and peptides, such as N-formyl peptides and TFAM, as well as lipids, and metabolites such as cardiolipin, succinate and ATP, and also mitochondrial DNA (mtDNA). Recent data indicate that somatic cells sense mitochondrial DAMPs and trigger protective mechanisms in response to these signals. In this review we focus on the well-described effects of mitochondrial DAMPs on immune cells and also how these molecules induce immunogenic responses in non-immune cells. Special attention will be paid to the response to mtDNA.
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Affiliation(s)
- Aida Rodríguez-Nuevo
- Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology, Barcelona, Spain.,Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, 08028 Barcelona, Spain.,CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III
| | - Antonio Zorzano
- Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology, Barcelona, Spain.,Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, 08028 Barcelona, Spain.,CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III
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6
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Cowan K, Anichtchik O, Luo S. Mitochondrial integrity in neurodegeneration. CNS Neurosci Ther 2019; 25:825-836. [PMID: 30746905 PMCID: PMC6566061 DOI: 10.1111/cns.13105] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 12/22/2018] [Accepted: 12/25/2018] [Indexed: 12/15/2022] Open
Abstract
The mitochondrion is a unique organelle with a diverse range of functions. Mitochondrial dysfunction is a key pathological process in several neurodegenerative diseases. Mitochondria are mostly important for energy production; however, they also have roles in Ca2+ homeostasis, ROS production, and apoptosis. There are two major systems in place, which regulate mitochondrial integrity, mitochondrial dynamics, and mitophagy. These two processes remove damaged mitochondria from cells and protect the functional mitochondrial population. These quality control systems often become dysfunctional during neurodegenerative diseases, such as Parkinson's and Alzheimer's disease, causing mitochondrial dysfunction and severe neurological symptoms.
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Affiliation(s)
- Katrina Cowan
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Plymouth, UK
| | - Oleg Anichtchik
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Plymouth, UK
| | - Shouqing Luo
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Plymouth, UK
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7
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Wang P, Fernandez-Sanz C, Wang W, Sheu SS. Why don't mice lacking the mitochondrial Ca 2+ uniporter experience an energy crisis? J Physiol 2018; 598:1307-1326. [PMID: 30218574 DOI: 10.1113/jp276636] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 08/28/2018] [Indexed: 01/15/2023] Open
Abstract
Current dogma holds that the heart balances energy demand and supply effectively and sustainably by sequestering enough Ca2+ into mitochondria during heartbeats to stimulate metabolic enzymes in the tricarboxylic acid (TCA) cycle and electron transport chain (ETC). This process is called excitation-contraction-bioenergetics (ECB) coupling. Recent breakthroughs in identifying the mitochondrial Ca2+ uniporter (MCU) and its associated proteins have opened up new windows for interrogating the molecular mechanisms of mitochondrial Ca2+ homeostasis regulation and its role in ECB coupling. Despite remarkable progress made in the past 7 years, it has been surprising, almost disappointing, that germline MCU deficiency in mice with certain genetic background yields viable pups, and knockout of the MCU in adult heart does not cause lethality. Moreover, MCU deficiency results in few adverse phenotypes, normal performance, and preserved bioenergetics in the heart at baseline. In this review, we briefly assess the existing literature on mitochondrial Ca2+ homeostasis regulation and then we consider possible explanations for why MCU-deficient mice are spared from energy crises under physiological conditions. We propose that MCU and/or mitochondrial Ca2+ may have limited ability to set ECB coupling, that other mitochondrial Ca2+ handling mechanisms may play a role, and that extra-mitochondrial Ca2+ may regulate ECB coupling. Since the heart needs to regenerate a significant amount of ATP to assure the perpetuation of heartbeats, multiple mechanisms are likely to work in concert to match energy supply with demand.
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Affiliation(s)
- Pei Wang
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, 98109, USA
| | - Celia Fernandez-Sanz
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Wang Wang
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, 98109, USA
| | - Shey-Shing Sheu
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
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8
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Qaid E, Zakaria R, Sulaiman SF, Yusof NM, Shafin N, Othman Z, Ahmad AH, Aziz CA. Insight into potential mechanisms of hypobaric hypoxia-induced learning and memory deficit - Lessons from rat studies. Hum Exp Toxicol 2017; 36:1315-1325. [PMID: 28111974 DOI: 10.1177/0960327116689714] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Impairment of memory is one of the most frequently reported symptoms during sudden hypoxia exposure in human. Cortical atrophy has been linked to the impaired memory function and is suggested to occur with chronic high-altitude exposure. However, the precise molecular mechanism(s) of hypoxia-induced memory impairment remains an enigma. In this work, we review hypoxia-induced learning and memory deficit in human and rat studies. Based on data from rat studies using different protocols of continuous hypoxia, we try to elicit potential mechanisms of hypobaric hypoxia-induced memory deficit.
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Affiliation(s)
- Eya Qaid
- 1 Department of Physiology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - R Zakaria
- 1 Department of Physiology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - S F Sulaiman
- 2 School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia
| | - Na Mohd Yusof
- 3 Department of Anatomy, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - N Shafin
- 1 Department of Physiology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - Z Othman
- 4 Department of Psychiatry, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - A H Ahmad
- 1 Department of Physiology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - Cb Abd Aziz
- 1 Department of Physiology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
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9
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Korde AS, Maragos WF. Direct exposure to N-methyl-d-aspartate alters mitochondrial function. Neurosci Lett 2016; 623:47-51. [DOI: 10.1016/j.neulet.2016.04.054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 04/25/2016] [Indexed: 10/21/2022]
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10
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Blomeyer CA, Bazil JN, Stowe DF, Dash RK, Camara AKS. Mg(2+) differentially regulates two modes of mitochondrial Ca(2+) uptake in isolated cardiac mitochondria: implications for mitochondrial Ca(2+) sequestration. J Bioenerg Biomembr 2016; 48:175-88. [PMID: 26815005 DOI: 10.1007/s10863-016-9644-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 01/12/2016] [Indexed: 12/14/2022]
Abstract
The manner in which mitochondria take up and store Ca(2+) remains highly debated. Recent experimental and computational evidence has suggested the presence of at least two modes of Ca(2+) uptake and a complex Ca(2+) sequestration mechanism in mitochondria. But how Mg(2+) regulates these different modes of Ca(2+) uptake as well as mitochondrial Ca(2+) sequestration is not known. In this study, we investigated two different ways by which mitochondria take up and sequester Ca(2+) by using two different protocols. Isolated guinea pig cardiac mitochondria were exposed to varying concentrations of CaCl2 in the presence or absence of MgCl2. In the first protocol, A, CaCl2 was added to the respiration buffer containing isolated mitochondria, whereas in the second protocol, B, mitochondria were added to the respiration buffer with CaCl2 already present. Protocol A resulted first in a fast transitory uptake followed by a slow gradual uptake. In contrast, protocol B only revealed a slow and gradual Ca(2+) uptake, which was approximately 40 % of the slow uptake rate observed in protocol A. These two types of Ca(2+) uptake modes were differentially modulated by extra-matrix Mg(2+). That is, Mg(2+) markedly inhibited the slow mode of Ca(2+) uptake in both protocols in a concentration-dependent manner, but not the fast mode of uptake exhibited in protocol A. Mg(2+) also inhibited Na(+)-dependent Ca(2+) extrusion. The general Ca(2+) binding properties of the mitochondrial Ca(2+) sequestration system were reaffirmed and shown to be independent of the mode of Ca(2+) uptake, i.e. through the fast or slow mode of uptake. In addition, extra-matrix Mg(2+) hindered Ca(2+) sequestration. Our results indicate that mitochondria exhibit different modes of Ca(2+) uptake depending on the nature of exposure to extra-matrix Ca(2+), which are differentially sensitive to Mg(2+). The implications of these findings in cardiomyocytes are discussed.
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Affiliation(s)
- Christoph A Blomeyer
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Jason N Bazil
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA.,Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - David F Stowe
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.,Department of Biomedical Engineering, Marquette University, Milwaukee, WI, 53233, USA.,Research Service, Zablocki Veterans Affairs Medical Center, Milwaukee, WI, 53295, USA
| | - Ranjan K Dash
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.,Department of Biomedical Engineering, Marquette University, Milwaukee, WI, 53233, USA
| | - Amadou K S Camara
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
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11
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Wang X, Pan T. Methionine Mistranslation Bypasses the Restraint of the Genetic Code to Generate Mutant Proteins with Distinct Activities. PLoS Genet 2015; 11:e1005745. [PMID: 26709516 PMCID: PMC4692448 DOI: 10.1371/journal.pgen.1005745] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 11/25/2015] [Indexed: 01/01/2023] Open
Abstract
Although mistranslation is commonly believed to be deleterious, recent evidence indicates that mistranslation can be actively regulated and be beneficial in stress response. Methionine mistranslation in mammalian cells is regulated by reactive oxygen species where cells deliberately alter the proteome through incorporating Met at non-Met positions to enhance oxidative stress response. However, it was not known whether specific, mistranslated mutant proteins have distinct activities from the wild-type protein whose sequence is restrained by the genetic code. Here, we show that Met mistranslation with and without Ca2+ overload generates specific mutant Ca2+/calmodulin-dependent protein kinase II (CaMKII) proteins substituting non-Met with Met at multiple locations. Compared to the genetically encoded wild-type CaMKII, specific mutant CaMKIIs can have distinct activation profiles, intracellular localization and enhanced phenotypes. Our results demonstrate that Met-mistranslation, or “Met-scan” can indeed generate mutant proteins in cells that expand the activity profile of the wild-type protein, and provide a molecular mechanism for the role of regulated mistranslation. Methionine-mistranslation is a recently discovered phenomenon where mammalian cells deliberately mischarge non-Met-tRNAs with amino acid methionine in unstressed cells and in response to innate immune and chemically triggered oxidative stress. These mischarged tRNAs are used in translation to generate mutant proteins containing non-Met to Met substitutions. Accumulating evidence shows that cells employ regulated mistranslation to enhance response to oxidative and other stresses. However, it was unknown whether any specific mutant proteins generated in mistranslation truly have distinct activities as the wild-type protein. Here, we identify and characterize naturally occurring Met-mistranslated proteins in human cells and show that specific Met-mistranslated proteins can have very distinct properties compared to the wild-type protein in vitro and in vivo. For the Ca2+/calmodulin-dependent protein kinase II (CaMKII), Met-mistranslated CaMKII show significant differences in catalytic activities, subcellular localization and elevated caspase-3 activity from the wild-type CaMKII. Our results provide a molecular mechanism on how mistranslation is used as an adaptive mechanism to stress, and establish Met-mistranslation as a nature’s way to overcome the restraint on the protein sequence by the genetic code.
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Affiliation(s)
- Xiaoyun Wang
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, United States of America
- * E-mail: (XW); (TP)
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, United States of America
- * E-mail: (XW); (TP)
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12
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Monaco G, Decrock E, Arbel N, van Vliet AR, La Rovere RM, De Smedt H, Parys JB, Agostinis P, Leybaert L, Shoshan-Barmatz V, Bultynck G. The BH4 domain of anti-apoptotic Bcl-XL, but not that of the related Bcl-2, limits the voltage-dependent anion channel 1 (VDAC1)-mediated transfer of pro-apoptotic Ca2+ signals to mitochondria. J Biol Chem 2015; 290:9150-61. [PMID: 25681439 DOI: 10.1074/jbc.m114.622514] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Indexed: 01/01/2023] Open
Abstract
Excessive Ca(2+) fluxes from the endoplasmic reticulum to the mitochondria result in apoptotic cell death. Bcl-2 and Bcl-XL proteins exert part of their anti-apoptotic function by directly targeting Ca(2+)-transport systems, like the endoplasmic reticulum-localized inositol 1,4,5-trisphosphate receptors (IP3Rs) and the voltage-dependent anion channel 1 (VDAC1) at the outer mitochondrial membranes. We previously demonstrated that the Bcl-2 homology 4 (BH4) domain of Bcl-2 protects against Ca(2+)-dependent apoptosis by binding and inhibiting IP3Rs, although the BH4 domain of Bcl-XL was protective independently of binding IP3Rs. Here, we report that in contrast to the BH4 domain of Bcl-2, the BH4 domain of Bcl-XL binds and inhibits VDAC1. In intact cells, delivery of the BH4-Bcl-XL peptide via electroporation limits agonist-induced mitochondrial Ca(2+) uptake and protects against staurosporine-induced apoptosis, in line with the results obtained with VDAC1(-/-) cells. Moreover, the delivery of the N-terminal domain of VDAC1 as a synthetic peptide (VDAC1-NP) abolishes the ability of BH4-Bcl-XL to suppress mitochondrial Ca(2+) uptake and to protect against apoptosis. Importantly, VDAC1-NP did not affect the ability of BH4-Bcl-2 to suppress agonist-induced Ca(2+) release in the cytosol or to prevent apoptosis, as done instead by an IP3R-derived peptide. In conclusion, our data indicate that the BH4 domain of Bcl-XL, but not that of Bcl-2, selectively targets VDAC1 and inhibits apoptosis by decreasing VDAC1-mediated Ca(2+) uptake into the mitochondria.
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Affiliation(s)
- Giovanni Monaco
- From the Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, and
| | - Elke Decrock
- the Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, 9000 Ghent, Belgium
| | - Nir Arbel
- the Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel, and
| | - Alexander R van Vliet
- Laboratory of Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Rita M La Rovere
- From the Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, and the Laboratory of Cellular Physiology, Department of Neuroscience Imaging and Clinical Sciences, Faculty of Pharmacy, "G. D'annunzio" University, 66013 Chieti, Italy
| | - Humbert De Smedt
- From the Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, and
| | - Jan B Parys
- From the Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, and
| | - Patrizia Agostinis
- Laboratory of Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Luc Leybaert
- the Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, 9000 Ghent, Belgium
| | - Varda Shoshan-Barmatz
- the Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel, and
| | - Geert Bultynck
- From the Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, and
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13
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Abstract
Decreased oxygen availability impairs cellular energy production and, without a coordinated and matched decrease in energy consumption, cellular and whole organism death rapidly ensues. Of particular interest are mechanisms that protect brain from low oxygen injury, as this organ is not only the most sensitive to hypoxia, but must also remain active and functional during low oxygen stress. As a result of natural selective pressures, some species have evolved molecular and physiological mechanisms to tolerate prolonged hypoxia with no apparent detriment. Among these mechanisms are a handful of responses that are essential for hypoxia tolerance, including (i) sensors that detect changes in oxygen availability and initiate protective responses; (ii) mechanisms of energy conservation; (iii) maintenance of basic brain function; and (iv) avoidance of catastrophic cell death cascades. As the study of hypoxia-tolerant brain progresses, it is becoming increasingly apparent that mitochondria play a central role in regulating all of these critical mechanisms. Furthermore, modulation of mitochondrial function to mimic endogenous neuroprotective mechanisms found in hypoxia-tolerant species confers protection against otherwise lethal hypoxic stresses in hypoxia-intolerant organs and organisms. Therefore, lessons gleaned from the investigation of endogenous mechanisms of hypoxia tolerance in hypoxia-tolerant organisms may provide insight into clinical pathologies related to low oxygen stress.
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Affiliation(s)
- Matthew E. Pamenter
- Department of Zoology, The University of British Columbia, #4200-6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
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14
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Berchtold MW, Villalobo A. The many faces of calmodulin in cell proliferation, programmed cell death, autophagy, and cancer. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:398-435. [PMID: 24188867 DOI: 10.1016/j.bbamcr.2013.10.021] [Citation(s) in RCA: 226] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Revised: 10/24/2013] [Accepted: 10/26/2013] [Indexed: 12/21/2022]
Abstract
Calmodulin (CaM) is a ubiquitous Ca(2+) receptor protein mediating a large number of signaling processes in all eukaryotic cells. CaM plays a central role in regulating a myriad of cellular functions via interaction with multiple target proteins. This review focuses on the action of CaM and CaM-dependent signaling systems in the control of vertebrate cell proliferation, programmed cell death and autophagy. The significance of CaM and interconnected CaM-regulated systems for the physiology of cancer cells including tumor stem cells, and processes required for tumor progression such as growth, tumor-associated angiogenesis and metastasis are highlighted. Furthermore, the potential targeting of CaM-dependent signaling processes for therapeutic use is discussed.
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Key Words
- (4-[3,5-bis-[2-(4-hydroxy-3-methoxy-phenyl)-ethyl]-4,5-dihydro-pyrazol-1-yl]-benzoic acid
- (4-[3,5-bis-[2-(4-hydroxy-3-methoxy-phenyl)-vinyl]-4,5-dihydro-pyrazol-1-yl]-phenyl)-(4-methyl-piperazin-1-yl)-methanone
- (−) enantiomer of dihydropyrine 3-methyl-5-3-(4,4-diphenyl-1-piperidinyl)-propyl-1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-piridine-3,5-dicarboxylate-hydrochloride (niguldipine)
- 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-l-tyrosyl]-4-phenylpiperazine
- 12-O-tetradecanoyl-phorbol-13-acetate
- 2-chloro-(ε-amino-Lys(75))-[6-(4-(N,N′-diethylaminophenyl)-1,3,5-triazin-4-yl]-CaM adduct
- 3′-(β-chloroethyl)-2′,4′-dioxo-3,5′-spiro-oxazolidino-4-deacetoxy-vinblastine
- 7,12-dimethylbenz[a]anthracene
- Apoptosis
- Autophagy
- B859-35
- CAPP(1)-CaM
- Ca(2+) binding protein
- Calmodulin
- Cancer biology
- Cell proliferation
- DMBA
- EBB
- FL-CaM
- FPCE
- HBC
- HBCP
- J-8
- KAR-2
- KN-62
- KN-93
- N-(4-aminobutyl)-2-naphthalenesulfonamide
- N-(4-aminobutyl)-5-chloro-2-naphthalenesulfonamide
- N-(6-aminohexyl)-1-naphthalenesulfonamide
- N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide
- N-8-aminooctyl-5-iodo-naphthalenesulfonamide
- N-[2-[N-(4-chlorocinnamyl)-N-methylaminomethyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzenesulfonamide
- O-(4-ethoxyl-butyl)-berbamine
- RITC-CaM
- TA-CaM
- TFP
- TPA
- W-12
- W-13
- W-5
- W-7
- fluorescein-CaM adduct
- fluphenazine-N-2-chloroethane
- norchlorpromazine-CaM adduct
- rhodamine isothiocyanate-CaM adduct
- trifluoperazine
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Affiliation(s)
- Martin W Berchtold
- Department of Biology, University of Copenhagen, Copenhagen Biocenter 4-2-09 Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark.
| | - Antonio Villalobo
- Instituto de Investigaciones Biomédicas, Department of Cancer Biology, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/Arturo Duperier 4, E-28029 Madrid, Spain.
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15
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Abstract
Calcium (Ca(2+)) uptake into the mitochondrial matrix is critically important to cellular function. As a regulator of matrix Ca(2+) levels, this flux influences energy production and can initiate cell death. If large, this flux could potentially alter intracellular Ca(2+) ([Ca(2+)]i) signals. Despite years of study, fundamental disagreements on the extent and speed of mitochondrial Ca(2+) uptake still exist. Here, we review and quantitatively analyze mitochondrial Ca(2+) uptake fluxes from different tissues and interpret the results with respect to the recently proposed mitochondrial Ca(2+) uniporter (MCU) candidate. This quantitative analysis yields four clear results: (i) under physiological conditions, Ca(2+) influx into the mitochondria via the MCU is small relative to other cytosolic Ca(2+) extrusion pathways; (ii) single MCU conductance is ∼6-7 pS (105 mM [Ca(2+)]), and MCU flux appears to be modulated by [Ca(2+)]i, suggesting Ca(2+) regulation of MCU open probability (P(O)); (iii) in the heart, two features are clear: the number of MCU channels per mitochondrion can be calculated, and MCU probability is low under normal conditions; and (iv) in skeletal muscle and liver cells, uptake per mitochondrion varies in magnitude but total uptake per cell still appears to be modest. Based on our analysis of available quantitative data, we conclude that although Ca(2+) critically regulates mitochondrial function, the mitochondria do not act as a significant dynamic buffer of cytosolic Ca(2+) under physiological conditions. Nevertheless, with prolonged (superphysiological) elevations of [Ca(2+)]i, mitochondrial Ca(2+) uptake can increase 10- to 1,000-fold and begin to shape [Ca(2+)]i dynamics.
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16
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Venditti P, Di Stefano L, Di Meo S. Mitochondrial metabolism of reactive oxygen species. Mitochondrion 2013; 13:71-82. [DOI: 10.1016/j.mito.2013.01.008] [Citation(s) in RCA: 219] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 01/16/2013] [Accepted: 01/22/2013] [Indexed: 11/16/2022]
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17
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EBV up-regulates cytochrome c through VDAC1 regulations and decreases the release of cytoplasmic Ca2+ in the NPC cell line. Cell Biol Int 2012; 36:733-8. [PMID: 22497278 DOI: 10.1042/cbi20110368] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
EBV (Epstein-Barr virus) is considered to be a major factor that causes NPC (nasopharyngeal carcinoma), which is one of the sneakiest cancers frequently occurring in Southeast Asia and Southern China. Apoptosis and pro-apoptotic signals have been studied for decades; however, few have extended the prevailing view of EBV to its impact on NPC in perspective of apoptosis. One of the important proteins named VDAC1 (voltage-dependent anion protein 1) on the mitochondrial outer membrane controls the pro-apoptotic signals in mammalian cells. The impact of EBV infection on VDAC1 and related apoptotic signals remains unclear. In order to study the VDAC1's role in EBV-infected NPC cells, we employ siRNA (small interfering RNA) inhibition to analyse the release of Ca2+ and Cyto c (cytochrome c) signals in the cytoplasm, as they are important pro-apoptotic signals. The results show a decrease of Ca2+ release and up-regulation of Cyto c with EBV infection. After siRNA transfection, the dysregulation of Cyto c is neutralized, which is evidence that the level of Cyto c release in virus-infected NPC cells is the as same as that of non-infected NPC cells. This result indicates that EBV infection changes the cytoplasmic level of Cyto c through regulating VDAC1. In summary, this study reports that EBV changes the release of Ca2+ and Cyto c in the cytoplasm of NPC cells, and that Cyto c changes are mediated by VDAC1 regulation.
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18
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Lu CB, Vreugdenhil M, Toescu EC. The effect of aging-associated impaired mitochondrial status on kainate-evoked hippocampal gamma oscillations. Neurobiol Aging 2012; 33:2692-703. [PMID: 22405041 PMCID: PMC3657166 DOI: 10.1016/j.neurobiolaging.2012.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 12/23/2011] [Accepted: 01/07/2012] [Indexed: 01/08/2023]
Abstract
Oscillations in hippocampal neuronal networks in the gamma frequency band have been implicated in various cognitive tasks and we showed previously that aging reduces the power of such oscillations. Here, using submerged hippocampal slices allowing simultaneous electrophysiological recordings and imaging, we studied the correlation between the kainate-evoked gamma oscillation and mitochondrial activity, as monitored by rhodamine 123. We show that the initiation of kainate-evoked gamma oscillations induces mitochondrial depolarization, indicating a metabolic response. Aging had an opposite effect on these parameters: while depressing the gamma oscillation strength, it increases mitochondrial depolarization. Also, in the aged neurons, kainate induced significantly larger Ca2+ signals. In younger slices, acute mitochondrial depolarization induced by low concentrations of mitochondrial protonophores strongly, but reversibly, inhibits gamma oscillations. These data indicating that the complex network activity required by the maintenance of gamma activity is susceptible to changes and modulations in mitochondrial status.
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Affiliation(s)
| | | | - Emil C. Toescu
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
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19
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Ben-Hail D, Lemelson D, Israelson A, Shoshan-Barmatz V. New fluorescent reagents specific for Ca2+-binding proteins. Biochem Biophys Res Commun 2012; 426:158-64. [DOI: 10.1016/j.bbrc.2012.08.060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 08/11/2012] [Indexed: 10/28/2022]
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20
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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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21
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Abstract
It has been known for more than 60 years, and suspected for over 100, that alveolar hypoxia causes pulmonary vasoconstriction by means of mechanisms local to the lung. For the last 20 years, it has been clear that the essential sensor, transduction, and effector mechanisms responsible for hypoxic pulmonary vasoconstriction (HPV) reside in the pulmonary arterial smooth muscle cell. The main focus of this review is the cellular and molecular work performed to clarify these intrinsic mechanisms and to determine how they are facilitated and inhibited by the extrinsic influences of other cells. Because the interaction of intrinsic and extrinsic mechanisms is likely to shape expression of HPV in vivo, we relate results obtained in cells to HPV in more intact preparations, such as intact and isolated lungs and isolated pulmonary vessels. Finally, we evaluate evidence regarding the contribution of HPV to the physiological and pathophysiological processes involved in the transition from fetal to neonatal life, pulmonary gas exchange, high-altitude pulmonary edema, and pulmonary hypertension. Although understanding of HPV has advanced significantly, major areas of ignorance and uncertainty await resolution.
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Affiliation(s)
- J. T. Sylvester
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Larissa A. Shimoda
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Philip I. Aaronson
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Jeremy P. T. Ward
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
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22
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Mitochondrial involvement in carbachol-induced intracellular Ca2+ mobilization and contraction in rat gastric smooth muscle. Life Sci 2011; 89:757-64. [DOI: 10.1016/j.lfs.2011.08.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 06/27/2011] [Accepted: 07/27/2011] [Indexed: 11/22/2022]
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23
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Bazil JN, Dash RK. A minimal model for the mitochondrial rapid mode of Ca²+ uptake mechanism. PLoS One 2011; 6:e21324. [PMID: 21731705 PMCID: PMC3121760 DOI: 10.1371/journal.pone.0021324] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 05/25/2011] [Indexed: 01/09/2023] Open
Abstract
Mitochondria possess a remarkable ability to rapidly accumulate and sequester Ca2+. One of the mechanisms responsible for this ability is believed to be the rapid mode (RaM) of Ca2+ uptake. Despite the existence of many models of mitochondrial Ca2+ dynamics, very few consider RaM as a potential mechanism that regulates mitochondrial Ca2+ dynamics. To fill this gap, a novel mathematical model of the RaM mechanism is developed herein. The model is able to simulate the available experimental data of rapid Ca2+ uptake in isolated mitochondria from both chicken heart and rat liver tissues with good fidelity. The mechanism is based on Ca2+ binding to an external trigger site(s) and initiating a brief transient of high Ca2+ conductivity. It then quickly switches to an inhibited, zero-conductive state until the external Ca2+ level is dropped below a critical value (∼100–150 nM). RaM's Ca2+- and time-dependent properties make it a unique Ca2+ transporter that may be an important means by which mitochondria take up Ca2+in situ and help enable mitochondria to decode cytosolic Ca2+ signals. Integrating the developed RaM model into existing models of mitochondrial Ca2+ dynamics will help elucidate the physiological role that this unique mechanism plays in mitochondrial Ca2+-homeostasis and bioenergetics.
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Affiliation(s)
- Jason N. Bazil
- Biotechnology and Bioengineering Center and Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Ranjan K. Dash
- Biotechnology and Bioengineering Center and Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- * E-mail:
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24
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Du H, Guo L, Zhang W, Rydzewska M, Yan S. Cyclophilin D deficiency improves mitochondrial function and learning/memory in aging Alzheimer disease mouse model. Neurobiol Aging 2011; 32:398-406. [PMID: 19362755 PMCID: PMC3304024 DOI: 10.1016/j.neurobiolaging.2009.03.003] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 01/28/2009] [Accepted: 03/03/2009] [Indexed: 01/11/2023]
Abstract
Mitochondrial stress is one of the early features of Alzheimer disease (AD). Mitochondrial Aβ has been linked to mitochondrial toxicity. Our recent study demonstrated that cyclophilin D (CypD) mediated mitochondrial permeability transition pore (mPTP) is an important mechanism for neuronal and synaptic stress induced by both Aβ and oxidative stress. In transgenic AD-type mice overexpressing mutant amyloid precursor protein (APP) and Aβ (mAPP), CypD deficiency improves mitochondrial and synaptic function and learning/memory up to 12 months old. Here we provide evidence of the protective effects of CypD deficiency in aged AD mice (22-24 months). Cyp D deficient mAPP mice demonstrate less calcium-induced mitochondrial swelling, increased mitochondrial calcium uptake capacity, preserved mitochondrial respiratory function and improved spatial learning/memory even in old age (known to be the age for late stage AD pathology and synaptic dysfunction). These data demonstrate that abrogation of CypD results in persistent life-long protection against Aβ toxicity in an Alzheimer's disease mouse model, thereby suggesting that blockade of CypD may be of benefit for Alzheimer disease treatment.
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Affiliation(s)
- Heng Du
- Department of Surgery, and Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, College of Physicians & Surgeons of Columbia University, 650 West 168th Street, New York, NY 10032, USA
| | - Lan Guo
- Department of Surgery, and Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, College of Physicians & Surgeons of Columbia University, 650 West 168th Street, New York, NY 10032, USA
| | - Wensheng Zhang
- Department of Surgery, and Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, College of Physicians & Surgeons of Columbia University, 650 West 168th Street, New York, NY 10032, USA
- Institute of Natural Medicine and Chinese Medicine Resources, Beijing Normal University, Beijing 100875, PR China
| | - Monika Rydzewska
- Department of Surgery, and Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, College of Physicians & Surgeons of Columbia University, 650 West 168th Street, New York, NY 10032, USA
| | - Shidu Yan
- Department of Surgery, and Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, College of Physicians & Surgeons of Columbia University, 650 West 168th Street, New York, NY 10032, USA
- Department of Pathology, and Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, College of Physicians & Surgeons of Columbia University, 650 West 168th Street, New York, NY 10032, USA
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25
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Subedi KP, Kim JC, Kang M, Son MJ, Kim YS, Woo SH. Voltage-dependent anion channel 2 modulates resting Ca²+ sparks, but not action potential-induced Ca²+ signaling in cardiac myocytes. Cell Calcium 2011; 49:136-43. [PMID: 21241999 DOI: 10.1016/j.ceca.2010.12.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 11/12/2010] [Accepted: 12/20/2010] [Indexed: 11/24/2022]
Abstract
Voltage-dependent anion channels (VDACs) are pore forming proteins predominantly found in the outer mitochondrial membrane and are thought to transport Ca(2+). In this study, we have investigated the possible role of type 2 VDAC (VDAC2) in cardiac Ca(2+) signaling and Ca(2+) sparks using a lentiviral knock-down (KD) technique and two-dimensional confocal Ca(2+) imaging in immortalized autorhythmic adult atrial cells, HL-1. We confirmed high expression of VDAC2 protein in ventricular, atrial, and HL-1 cells using Western blot analysis. Infection of HL-1 cells with VDAC2-targeting lentivirus reduced the level of VDAC2 protein to ∼10%. Comparisons of autorhythmic Ca(2+) transients between wild-type (WT) and VDAC2 KD cells showed no significant change in the magnitude, decay, and beating rate of the Ca(2+) transients. Caffeine (10mM)-induced Ca(2+) release, which indicates sarcoplasmic reticulum (SR) Ca(2+) content, was not altered by VDAC2 KD. Interestingly, however, the intensity, width, and duration of the individual Ca(2+) sparks were significantly increased by VDAC2 KD in resting conditions, with no change in the frequency of sparks. VDAC2 KD significantly delayed mitochondrial Ca(2+) uptake during artificial Ca(2+) pulses in permeabilized HL-1 cells. These results suggest that VDAC2 may facilitate mitochondrial Ca(2+) uptake and restrict Ca(2+) spark expansion without regulating activations of sparks under resting conditions, thereby providing evidence on the functional role of VDAC2 in cardiac local Ca(2+) signaling.
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Affiliation(s)
- Krishna Prasad Subedi
- College of Pharmacy, IDRD, Chungnam National University, 220 Gung-dong, Yuseong-gu, Daejeon 305-764, South Korea
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26
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Rosenstock TR, Bertoncini CRA, Teles AV, Hirata H, Fernandes MJS, Smaili SS. Glutamate-induced alterations in Ca2+ signaling are modulated by mitochondrial Ca2+ handling capacity in brain slices of R6/1 transgenic mice. Eur J Neurosci 2011; 32:60-70. [PMID: 20608968 DOI: 10.1111/j.1460-9568.2010.07268.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Huntington's disease is a neurodegenerative disorder caused by an expansion of CAGs repeats and characterized by alterations in mitochondrial functions. Although changes in Ca(2+) handling have been suggested, the mechanisms involved are not completely understood. The aim of this study was to investigate the possible alterations in Ca(2+) handling capacity and the relationship with mitochondrial dysfunction evaluated by NAD(P)H fluorescence, reactive oxygen species levels, mitochondrial membrane potential (DeltaPsi(m)) measurements and respiration in whole brain slices from R6/1 mice of different ages, evaluated in situ by real-time real-space microscopy. We show that the cortex and striatum of the 9-month-old R6/1 transgenic mice present a significant sustained increase in cytosolic Ca(2+) induced by glutamate (Glu). This difference in Glu response was partially reduced in R6/1 when in the absence of extracellular Ca(2+), indicating that N-methyl-D-aspartate receptors participation in this response is more important in transgenic mice. In addition, Glu also lead to a decrease in NAD(P)H fluorescence, a loss in DeltaPsi(m) and a further increase in respiration, which may have evoked a decrease in mitochondrial Ca(2+) Ca(2+)(m) uptake capacity. Taken together, these results show that alterations in Ca(2+) homeostasis in transgenic mice are associated with a decrease in Ca(2+)(m) uptake mechanism with a diminished Ca(2+) handling ability that ultimately causes dysfunctions and worsening of the neurodegenerative and the disease processes.
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Affiliation(s)
- T R Rosenstock
- Departamento de Farmacologia, Universidade Federal de São Paulo (UNIFESP/EPM), São Paulo, SP, Brazil
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27
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Ichimura T, Ito M, Takahashi K, Oyama K, Sakurai K. Involvement of mitochondrial swelling in cytochrome c release from mitochondria treated with calcium and Alloxan. ACTA ACUST UNITED AC 2011. [DOI: 10.4236/jbpc.2011.21002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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28
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Contreras L, Drago I, Zampese E, Pozzan T. Mitochondria: the calcium connection. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:607-18. [PMID: 20470749 DOI: 10.1016/j.bbabio.2010.05.005] [Citation(s) in RCA: 252] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 05/04/2010] [Accepted: 05/04/2010] [Indexed: 12/21/2022]
Abstract
Calcium handling by mitochondria is a key feature in cell life. It is involved in energy production for cell activity, in buffering and shaping cytosolic calcium rises and also in determining cell fate by triggering or preventing apoptosis. Both mitochondria and the mechanisms involved in the control of calcium homeostasis have been extensively studied, but they still provide researchers with long-standing or even new challenges. Technical improvements in the tools employed for the investigation of calcium dynamics have been-and are still-opening new perspectives in this field, and more prominently for mitochondria. In this review we present a state-of-the-art toolkit for calcium measurements, with major emphasis on the advantages of genetically encoded indicators. These indicators can be efficiently and selectively targeted to specific cellular sub-compartments, allowing previously unavailable high-definition calcium dynamic studies. We also summarize the main features of cellular and, in more detail, mitochondrial calcium handling, especially focusing on the latest breakthroughs in the field, such as the recent direct characterization of the calcium microdomains that occur on the mitochondrial surface upon cellular stimulation. Additionally, we provide a major example of the key role played by calcium in patho-physiology by briefly describing the extensively reported-albeit highly controversial-alterations of calcium homeostasis in Alzheimer's disease, casting lights on the possible alterations in mitochondrial calcium handling in this pathology.
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Affiliation(s)
- Laura Contreras
- Department of Biomedical Sciences, University of Padua, Italy.
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29
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Ho MY, Chiou ML, Chang RC, Chen YH, Cheng CC. Outer membrane protein OmpF involved in the transportation of polypyridyl ruthenium complexes into Escherichia coli. J Inorg Biochem 2010; 104:614-7. [DOI: 10.1016/j.jinorgbio.2010.01.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 01/28/2010] [Accepted: 01/28/2010] [Indexed: 10/19/2022]
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30
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31
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VDAC, a multi-functional mitochondrial protein regulating cell life and death. Mol Aspects Med 2010; 31:227-85. [PMID: 20346371 DOI: 10.1016/j.mam.2010.03.002] [Citation(s) in RCA: 530] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 03/17/2010] [Indexed: 01/22/2023]
Abstract
Research over the past decade has extended the prevailing view of the mitochondrion to include functions well beyond the generation of cellular energy. It is now recognized that mitochondria play a crucial role in cell signaling events, inter-organellar communication, aging, cell proliferation, diseases and cell death. Thus, mitochondria play a central role in the regulation of apoptosis (programmed cell death) and serve as the venue for cellular decisions leading to cell life or death. One of the mitochondrial proteins controlling cell life and death is the voltage-dependent anion channel (VDAC), also known as mitochondrial porin. VDAC, located in the mitochondrial outer membrane, functions as gatekeeper for the entry and exit of mitochondrial metabolites, thereby controlling cross-talk between mitochondria and the rest of the cell. VDAC is also a key player in mitochondria-mediated apoptosis. Thus, in addition to regulating the metabolic and energetic functions of mitochondria, VDAC appears to be a convergence point for a variety of cell survival and cell death signals mediated by its association with various ligands and proteins. In this article, we review what is known about the VDAC channel in terms of its structure, relevance to ATP rationing, Ca(2+) homeostasis, protection against oxidative stress, regulation of apoptosis, involvement in several diseases and its role in the action of different drugs. In light of our recent findings and the recently solved NMR- and crystallography-based 3D structures of VDAC1, the focus of this review will be on the central role of VDAC in cell life and death, addressing VDAC function in the regulation of mitochondria-mediated apoptosis with an emphasis on structure-function relations. Understanding structure-function relationships of VDAC is critical for deciphering how this channel can perform such a variety of functions, all important for cell life and death. This review also provides insight into the potential of VDAC1 as a rational target for new therapeutics.
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32
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Fang X, Balgley BM, Lee CS. Recent advances in capillary electrophoresis-based proteomic techniques for biomarker discovery. Electrophoresis 2010; 30:3998-4007. [PMID: 19960464 DOI: 10.1002/elps.200900219] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A compelling need exists for the development of technologies that facilitate and accelerate the discovery of novel protein biomarkers with therapeutic and diagnostic potential. The inherent disadvantage of biomarker dilution in complex biological fluids such as serum/plasma, urine, and saliva necessitates highly sensitive analytical approaches, often exceeding the dynamic range of currently available proteomic platforms. Thus, investigative studies directed at tissues obtained from the primary site of pathology probably afford the best opportunity for the discovery of disease biomarkers. This review therefore focuses on the most recent advances in capillary electrophoresis-based single and multidimensional separations coupled with ESI-MS for performing comprehensive and comparative analysis of protein expression profiles within clinical specimens. Advanced sample preparation techniques, including tissue microdissection, detergent-based membrane protein extraction, and heat-induced protein retrieval, further enable targeted protein profiling of both fresh-frozen, formalin-fixed, and paraffin-embedded tissues. Comparative proteomics involving measurements in changes of biological pathways or functional processes are expected to provide relevant disease-associated markers and networks, molecular relationships among different stages of disease, and molecular mechanisms that drive the progression of disease. From a practical perspective, the evaluation of comparative proteomic dataset within a biological context is essential for high-throughput data validation, prioritization of follow-on biomarker selection, and validation experiments.
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Affiliation(s)
- Xueping Fang
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
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33
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Mitochondrial ion transport pathways: role in metabolic diseases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:832-8. [PMID: 20044972 DOI: 10.1016/j.bbabio.2009.12.017] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Revised: 12/16/2009] [Accepted: 12/21/2009] [Indexed: 12/22/2022]
Abstract
Mitochondria are the central coordinators of energy metabolism and alterations in their function and number have long been associated with metabolic disorders such as obesity, diabetes and hyperlipidemias. Since oxidative phosphorylation requires an electrochemical gradient across the inner mitochondrial membrane, ion channels in this membrane certainly must play an important role in the regulation of energy metabolism. However, in many experimental settings, the relationship between the activity of mitochondrial ion transport and metabolic disorders is still poorly understood. This review briefly summarizes some aspects of mitochondrial H+ transport (promoted by uncoupling proteins, UCPs), Ca2+ and K+ uniporters which may be determinant in metabolic disorders.
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34
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Modelling muscle energy-metabolism in anaerobic muscle. Meat Sci 2009; 85:134-48. [PMID: 20374877 DOI: 10.1016/j.meatsci.2009.12.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 12/07/2009] [Accepted: 12/11/2009] [Indexed: 11/21/2022]
Abstract
A mathematical model of anaerobic muscle energy-metabolism was developed to predict pH and the concentrations of nine muscle metabolites over time. Phosphorous-31 Nuclear Magnetic Resonance was used to measure time-course data for some phosphate metabolites and pH in anoxic M. semitendinosus taken from three slaughtered sheep. Muscles were held at 35 degrees C during the experiment. Measurement commenced 25 min post mortem and concluded before rigor mortis. The model was fitted to these data within experimental error, by simultaneously varying model parameter values and initial substrate concentrations. The model was used to simulate the period from death until metabolic activity ceased, in order to predict the different stages of metabolic response to anoxia. The model suggested that alkalinisation would occur in all three muscles in the first few minutes after the onset of anoxia, followed by a steady decline in pH. For two of the muscles this decline continued until rigor, with final pH values of 5.60 and 6.07. For the other muscle, pH reached a low of 5.60 near rigor but then increased to a final value of 5.73. A rise in pH after rigor has been observed but not previously explained in the literature. The modelling results suggest it was caused by the alkalising effect of adenosine monophosphate deamination being greater at low pH than the acidifying effect of inosine monophosphate dephosphorylation.
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35
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Abstract
Proper cell activity requires an efficient exchange of molecules between mitochondria and cytoplasm. Lying in the outer mitochondrial membrane, VDAC assumes a crucial position in the cell, forming the main interface between the mitochondrial and the cellular metabolisms. As such, it has been recognized that VDAC plays a crucial role in regulating the metabolic and energetic functions of mitochondria. Indeed, down-regulation of VDAC1 expression by shRNA leads to a decrease in energy production and cell growth. VDAC has also been recognized as a key protein in mitochondria-mediated apoptosis through its involvement in the release of apoptotic proteins located in the inter-membranal space and as the proposed target of pro- and anti-apoptotic members of the Bcl2-family and of hexokinase. Questions, however, remain as to if and how VDAC mediates the transfer of apoptotic proteins from the inter-membranal space to the cytosol. The diameter of the VDAC pore is only about 2.5-3 nm, insufficient for the passage of a folded protein like cytochrome c. New work, however, suggests that pore formation involves the assembly of homo-oligomers of VDAC or hetero-oligomers composed of VDAC and pro-apoptotic proteins, such as Bax. Thus, VDAC appears to represent a convergence point for a variety of cell survival and cell death signals. This review provides insight into the central role of VDAC in mammalian cell life and death, emphasizing VDAC function in the regulation of mitochondria-mediated apoptosis and, as such, its potential as a rational target for new therapeutics.
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Bakuridze K, Duzenli S, Gepdiremen A. The Role of Ruthenium Red as a Partial Agonist in Caffeine-Induced Neurotoxicity in Cerebellar Granular Cell Culture of Rats. Int J Neurosci 2009; 115:13-21. [PMID: 15768848 DOI: 10.1080/00207450490512614] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Caffeine is widely spread and well known as a mild stimulant of the central nervous system. The present study tested the role of caffeine and Ruthenium red on the intact neuronal cells alone and Ruthenium red in caffeine-induced neurotoxicity. One-day-old newborn rats were used to obtain cerebellar cell cultures. Caffeine at a concentration of 1 mM was found to be most toxic. Dead cell scores were 5.9 +/- 0.8 for control, and 56.2 +/- 3.4 for caffeine (p < .001). Ruthenium red alone has also caused the reduction in neuronal cell number 36.1 +/- 4.5 for 10(-5) and 47 +/- 2.7 for 10(-6) M concentrations (p < .001 for both). Interestingly Ruthenium red used in caffeine-induced neurotoxicity has partly diminished the number of dead cells 28.7 +/- 3.2 for 10(-5) and 23.8 +/- 2.27 for 10(-6) M concentrations (p < .001for both). The results suggest that both Ruthenium red and caffeine are neurotoxic alone but, in combination, the neurotoxicity may be reduced through partial agonistic action.
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Affiliation(s)
- Kakhi Bakuridze
- Department of Pharmacology, Tbilisi State Medical University, Tbilisi, Georgia, USA
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Murgia M, Giorgi C, Pinton P, Rizzuto R. Controlling metabolism and cell death: at the heart of mitochondrial calcium signalling. J Mol Cell Cardiol 2009; 46:781-8. [PMID: 19285982 PMCID: PMC2851099 DOI: 10.1016/j.yjmcc.2009.03.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 03/05/2009] [Accepted: 03/06/2009] [Indexed: 10/21/2022]
Abstract
Transient increases in intracellular calcium concentration activate and coordinate a wide variety of cellular processes in virtually every cell type. This review describes the main homeostatic mechanisms that control Ca(2+) transients, focusing on the mitochondrial checkpoint. We subsequently extend this paradigm to the cardiomyocyte and to the interplay between cytosol, endoplasmic reticulum and mitochondria that occurs beat-to-beat in excitation-contraction coupling. The mechanisms whereby mitochondria decode fast cytosolic calcium spikes are discussed in the light of the results obtained with recombinant photoproteins targeted to the mitochondrial matrix of contracting cardiomyocytes. Mitochondrial calcium homeostasis is then highlighted as a crucial point of convergence of the environmental signals that mediate cardiac cell death, both by necrosis and by apoptosis. Altogether we point to a role of the mitochondrion as an integrator of calcium signalling and a fundamental decision maker in cardiomyocyte metabolism and survival.
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Affiliation(s)
- Marta Murgia
- Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, 35121 Padua, Italy
| | - Carlotta Giorgi
- Department of Experimental and Diagnostic Medicine, Section of General Pathology, Interdisciplinary Center for the Study of Inflammation (ICSI) and Emilia Romagna Laboratory BioPharmaNet, University of Ferrara, Via Borsari 46, 44100 Ferrara; Italy
| | - Paolo Pinton
- Department of Experimental and Diagnostic Medicine, Section of General Pathology, Interdisciplinary Center for the Study of Inflammation (ICSI) and Emilia Romagna Laboratory BioPharmaNet, University of Ferrara, Via Borsari 46, 44100 Ferrara; Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, 35121 Padua, Italy
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Jiang YJ, Sun Q, Fang XS, Wang X. Comparative mitochondrial proteomic analysis of Rji cells exposed to adriamycin. Mol Med 2009; 15:173-82. [PMID: 19209238 DOI: 10.2119/molmed.2008.00129] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2009] [Accepted: 02/04/2009] [Indexed: 02/01/2023] Open
Abstract
The antitumor mechanisms of adriamycin (ADR) have been thought to contribute to induction of apoptosis and inefficiency of DNA repair, processes that are to a large extent mediated by mitochondria. This study aimed to investigate characteristics of ADR, including its antineoplastic activity, drug resistance, and unexpected toxicity in non-Hodgkin lymphoma (NHL) Raji cells at the mitochondrial proteomic level. The alterations of the mitochondrial proteome of Raji cells treated with ADR were analyzed by two-dimensional differential in-gel electrophoresis (2D-DIGE) coupled with linear ion trap quadrupole-electrospray ionization tandem mass spectrometry (LTQ-ESI-MS/MS).The altered patterns of three identified proteins were validated by Western blot and analyzed by pathway studio software. The results showed that 34 proteins were downregulated and 3 proteins upregulated in the study group compared with the control group. The differentially expressed proteins distributed their functions in reduction-oxidation reactions, DNA repair, cell cycle regulation, transporters and channels, and oxidative phosphorylation. Furthermore, heat shock protein 70 (HSP70), ATP-binding cassette transporter isoform B6 (ABCB6), and prohibitin (PHB) identified in this study may be closely related to chemoresistance and could serve as potential chemotherapeutic targets for NHL. Collectively, these results suggest that specific mitochondrial proteins are uniquely susceptible to alterations in abundance following exposure to ADR and carry implications for the investigation of therapeutic and prognostic markers. Further studies focusing on these identified proteins will be used to predict treatment response and reverse apoptosis resistance,and to explore drug-combination strategies associated with ADR for NHL therapy.
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Affiliation(s)
- Yu-Jie Jiang
- Department of Hematology, Provincial Hospital affiliated to Shandong University, Jinan, China
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Chapter 3 Proteome Characterization of Mouse Brain Mitochondria Using Electrospray Ionization Tandem Mass Spectrometry. Methods Enzymol 2009; 457:49-62. [DOI: 10.1016/s0076-6879(09)05003-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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40
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Fang X, Wang W, Yang L, Chandrasekaran K, Kristian T, Balgley BM, Lee CS. Application of capillary isotachophoresis-based multidimensional separations coupled with electrospray ionization-tandem mass spectrometry for characterization of mouse brain mitochondrial proteome. Electrophoresis 2008; 29:2215-23. [PMID: 18425750 DOI: 10.1002/elps.200700609] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
By employing a capillary ITP (CITP)/CZE-based proteomic technology, a total of 1795 distinct mouse Swiss-Prot protein entries (or 1705 nonredundant proteins) are identified from synaptic mitochondria isolated from mouse brain. The ultrahigh resolving power of CITP/CZE is evidenced by the large number of distinct peptide identifications measured from each CITP fraction together with the low peptide fraction overlapping among identified peptides. The degree of peptide overlapping among CITP fractions is even lower than that achieved using combined CIEF/nano-RP LC separations for the analysis of the same mitochondrial sample. When evaluating the protein sequence coverage by the number of distinct peptides mapping to each mitochondrial protein identification, CITP/CZE similarly achieves superior performance with 1041 proteins (58%) having 3 or more distinct peptides, 233 (13%) having 2 distinct peptides, and 521 (29%) having a single distinct peptide. The reproducibility of protein identifications is found to be around 86% by comparing proteins identified from repeated runs of the same mitochondrial sample. The analysis of the mouse mitochondrial proteome by two CITP/CZE runs results in the detection of 2095 distinct mouse Swiss-Prot protein entries (or 1992 nonredundant proteins), corresponding to 59% coverage of the updated Maestro mitochondrial reference set. The collective analysis from combined CITP/CZE and CIEF-based proteomic studies yields the identification of 2191 distinct mitochondrial protein entries (or 2082 nonredundant proteins), corresponding to 76% coverage of the MitoP2-database reference set.
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Affiliation(s)
- Xueping Fang
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
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41
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Israelson A, Zaid H, Abu-Hamad S, Nahon E, Shoshan-Barmatz V. Mapping the ruthenium red-binding site of the voltage-dependent anion channel-1. Cell Calcium 2008; 43:196-204. [PMID: 17590433 DOI: 10.1016/j.ceca.2007.05.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 04/28/2007] [Accepted: 05/03/2007] [Indexed: 11/28/2022]
Abstract
We have previously shown that ruthenium red (RuR) binds to the voltage-dependent anion channel (VDAC) in the outer mitochondrial membrane, decreasing channel conductance and protecting against apoptotic cell death. In this report, we define the murine and yeast VDAC1 amino acid residues involved in the interaction with RuR. Binding of RuR to bilayer-reconstituted mVDAC1 and the resulting channel closure was inhibited upon mutation of specific VDAC1 residues. RuR protection against cell death, as induced by overexpression of native or mutated mVDAC1, was also diminished upon mutation of these amino acids. Moreover, RuR-mediated inhibition of cytochrome c release normally induced by staurosporine was not observed in cells expressing mutants VDAC1. We found that four glutamate residues, two each located in the first and third mVDAC1 cytosolic loops, are required for the interaction of VDAC1 with RuR and subsequent protection against cell death. Similar results were obtained with Q72E-yeast VDAC1, except that only three glutamate residues, located in two cytosolic loops were required. As a hexavalent reagent, RuR is expected to bind to more than one negatively charged group. Our results thus clearly indicate that RuR protects against cell death via a direct interaction with VDAC1 to inhibit cytochrome c release and subsequent cell death.
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Affiliation(s)
- Adrian Israelson
- Department of Life Sciences, National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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42
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Reinert KC, Gao W, Chen G, Ebner TJ. Flavoprotein autofluorescence imaging in the cerebellar cortex in vivo. J Neurosci Res 2008; 85:3221-32. [PMID: 17520745 DOI: 10.1002/jnr.21348] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Autofluorescence optical imaging is rapidly becoming a widely used tool for mapping activity in the central nervous system function in vivo and investigating the coupling among neurons, glia, and metabolism. This paper provides a brief review of autofluorescence and of our recent work using flavoprotein imaging in the cerebellar cortex. Stimulation of the parallel fibers evokes an intrinsic fluorescence signal that is tightly coupled to neuronal activation and primarily generated postsynaptically. The signal originates from mitochondrial flavoproteins. The signal is biphasic, with the initial increase in fluorescence (light phase) resulting from the oxidation of flavoproteins and the subsequent decrease (dark phase) from the reduction of flavoproteins. The light phase is primarily neuronal, and the dark phase is primarily glial. Exploiting the spatial properties of molecular layer inhibition in the cerebellar cortex, we show that flavoprotein autofluorescence can monitor both excitatory and inhibitory activity in the cerebellar cortex. Furthermore, flavoprotein autofluorescence has revealed that molecular layer inhibition is organized into parasagittal domains that differentially modulate the spatial pattern of cerebellar cortical activity. The reduction in flavoprotein autofluorescence occurring in the inhibitory bands most likely reflects a decrease in intracellular Ca(2+) in the neurons inhibited by the molecular layer interneurons. Therefore, flavoprotein autofluorescence imaging is providing new insights into cerebellar cortical function and neurometabolic coupling.
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Affiliation(s)
- Kenneth C Reinert
- Department of Neuroscience, University of Minnesota, 421 Lions Research Building, Minneapolis, MN 55455, USA
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43
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Barhwal K, Singh SB, Hota SK, Jayalakshmi K, Ilavazhagan G. Acetyl-l-Carnitine ameliorates hypobaric hypoxic impairment and spatial memory deficits in rats. Eur J Pharmacol 2007; 570:97-107. [PMID: 17610872 DOI: 10.1016/j.ejphar.2007.05.063] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Revised: 05/26/2007] [Accepted: 05/30/2007] [Indexed: 10/23/2022]
Abstract
Inadequate oxygen availability at high altitude causes oxidative stress and generation of reactive oxygen species, which may lead to memory impairment. Hippocampus, which plays a key role in the learning and memory processes, is especially vulnerable to hypoxic damage. The present study was aimed at investigating the effect of acetyl-L-carnitine on spatial working and reference memory deficits along with oxidative and apoptotic damage, caused by hypobaric hypoxia in male Sprague Dawley rats. Rats were trained in Morris Water Maze for eight days after which they were submitted to chronic hypobaric hypoxia exposure at a simulated altitude of 6100 m for three days. Rats received daily acetyl-L-carnitine at a dosage of 75 mg/kg body weight orally during exposure. Subsequent to exposure, performance of the animals was tested in Morris Water Maze, which revealed working memory impairment that was significantly improved by acetyl-L-carnitine. However, there was no change in the reference memory after hypobaric hypoxia exposure. Following behavioral study animals were sacrificed and biomarkers of oxidative damage like free radical production, lactate dehydrogenase activity, lipid peroxidation, antioxidant status and expression of apoptotic [viz. caspase-3, Apoptosis activating factor (Apaf-1), bax, cytochrome c] and anti-apoptotic protein-Bcl-2 were studied in the hippocampus. There was a significant increase in oxidative stress along with increased expression of apoptotic proteins and NR1 subunit of glutamate receptor indicating occurrence of excitotoxicity in hypoxia exposed rats. These results suggested that supplementation with acetyl-L-carnitine improves spatial working memory deficits reduces oxidative stress and inhibits apoptotic cascade induced by hypoxia.
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Affiliation(s)
- Kalpana Barhwal
- Defence Institute of Physiology and Allied Sciences, Defence Research and Development Organization, Lucknow Road, Timarpur, Delhi-110054, India
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44
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Bagnaresi P, Rodrigues MT, Garcia CRS. Calcium signaling in lizard red blood cells. Comp Biochem Physiol A Mol Integr Physiol 2007; 147:779-787. [PMID: 17095273 DOI: 10.1016/j.cbpa.2006.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 09/21/2006] [Accepted: 09/25/2006] [Indexed: 11/16/2022]
Abstract
The ion calcium is a ubiquitous second messenger, present in all eukaryotic cells. It modulates a vast number of cellular events, such as cell division and differentiation, fertilization, cell volume, decodification of external stimuli. To process this variety of information, the cells display a number of calcium pools, which are capable of mobilization for signaling purposes. Here we review the calcium signaling on lizards red blood cells, an interesting model that has been receiving an increasing notice recently. These cells possess a complex machinery to regulate calcium, and display calcium responses to extracellular agonists. Interestingly, the pattern of calcium handling and response are divergent in different lizard families, which enforces the morphological data to their phylogenetic classification, and suggest the radiation of different calcium signaling models in lizards evolution.
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Affiliation(s)
- Piero Bagnaresi
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Miguel T Rodrigues
- Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Célia R S Garcia
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
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45
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Abstract
Physiological stimuli causing an increase of cytosolic free Ca2+ [Ca2+], or the release of Ca2+ from the endoplasmic reticulum invariably induce mitochondrial Ca2+ uptake, with a rise of mitochondrial matrix free [Ca2+] ([Ca2+]m). The [Ca2+]m rise occurs despite the low affinity of the mitochondrial Ca2+ uptake systems measured in vitro and the often limited amplitude of the cytoplasmic [Ca2+]c increases. The [Ca2+]m increase is typically in the 0.2-3 microM range, which allows the activation of Ca2(+)-regulated enzymes of the Krebs cycle; and it rapidly returns to the resting level if the [Ca2+], rise recedes due to activation of mitochondrial efflux mechanisms and matrix Ca2+ buffering. Mitochondria thus accumulate Ca2+ and efficiently control the spatial and temporal shape of cellular Ca2+ signals, yet this situation exposes them to the hazards of Ca2+ overload. Indeed, mitochondrial Ca2+, which is so important for metabolic regulation, can become a death factor by inducing opening of the permeability transition pore (PTP), a high conductance inner membrane channel. Persistent PTP opening is followed by depolarization with Ca2+ release, cessation of oxidative phosphorylation, matrix swelling with inner'membrane remodeling and eventually outer membrane rupture with release of cytochrome c and other apoptogenic proteins. Understanding the mechanisms through which the Ca2+ signal can be shifted from a physiological signal into a pathological effector is an unresolved problem of modern pathophysiology that holds great promise for disease treatment.
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Affiliation(s)
- P Bernardi
- Department of Biomedical Sciences, University of Padova, Viale Giuseppe Colombo 3, 35121 Padova, Italy
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46
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Kosterin P, Kim GH, Muschol M, Obaid AL, Salzberg BM. Changes in FAD and NADH fluorescence in neurosecretory terminals are triggered by calcium entry and by ADP production. J Membr Biol 2006; 208:113-24. [PMID: 16645741 DOI: 10.1007/s00232-005-0824-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Indexed: 10/24/2022]
Abstract
We measured changes in the intrinsic fluorescence (IF) of the neurosecretory terminals of the mouse neurohypophysis during brief (1-2 s) trains of stimuli. With fluorescence excitation at either 350 +/- 20 or 450 +/- 50 nm, and with emission measured, respectively, at 450 +/- 50 or > or = 520 nm, DeltaF/F(o) was approximately 5-8 % for a 2 s train of 30 action potentials. The IF changes lagged the onset of stimulation by approximately 100 ms and were eliminated by 1 microM tetrodotoxin (TTX). The signals were partially inhibited by 500 microM Cd(2+), by substitution of Mg(2+) for Ca(2+), by Ca(2+)-free Ringer's with 0.5 mM EGTA, and by 50 microM ouabain. The IF signals were also sensitive to the mitochondrial metabolic inhibitors CCCP (0.3 microM), FCCP (0.3 microM), and NaN(3) (0.3 mM), and their amplitude reflected the partial pressure of oxygen (pO(2)) in the bath. Resting fluorescence at both 350 nm and 450 nm exhibited significant bleaching. Flavin adenine dinucleotide (FAD) is fluorescent, while its reduced form FADH(2) is relatively non-fluorescent; conversely, NADH is fluorescent, while its oxidized form NAD is non-fluorescent. Thus, our experiments suggest that the stimulus-coupled rise in [Ca(2+)](i) triggers an increase in FAD and NAD as FADH(2) and NADH are oxidized, but that elevation of [Ca(2+)](i), alone cannot account for the totality of changes in intrinsic fluorescence.
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Affiliation(s)
- P Kosterin
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, 19104, USA
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Lee WK, Thévenod F. A role for mitochondrial aquaporins in cellular life-and-death decisions? Am J Physiol Cell Physiol 2006; 291:C195-202. [PMID: 16624989 DOI: 10.1152/ajpcell.00641.2005] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondria dominate the process of life-and-death decisions of the cell. Continuous generation of ATP is essential for cell sustenance, but, on the other hand, mitochondria play a central role in the orchestra of events that lead to apoptotic cell death. Changes of mitochondrial volume contribute to the modulation of physiological mitochondrial function, and several ion permeability pathways located in the inner mitochondrial membrane have been implicated in the mediation of physiological swelling-contraction reactions, such as the K+ cycle. However, the channels and transporters involved in these processes have not yet been identified. Osmotic swelling is also one of the fundamental characteristics exhibited by mitochondria in pathological situations, which activates downstream cascades, culminating in apoptosis. The permeability transition pore has long been postulated to be the primary mediator for water movement in mitochondrial swelling during cell death, but its molecular identity remains obscure. Inevitably, accumulating evidence shows that mitochondrial swelling induced by apoptotic stimuli can also occur independently of permeability transition pore activation. Recently, a novel mechanism for osmotic swelling of mitochondria has been described. Aquaporin-8 and -9 channels have been identified in the inner mitochondrial membrane of various tissues, including the kidney, liver, and brain, where they may mediate water transport associated with physiological volume changes, contribute to the transport of metabolic substrates, and/or participate in osmotic swelling induced by apoptotic stimuli. Hence, the recent discovery that aquaporins are expressed in mitochondria opens up new areas of investigation in health and disease.
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Affiliation(s)
- Wing-Kee Lee
- Dept. Physiology and Pathophysiology, Univ. of Witten/Herdecke, Faculty of Medicine, D-58448 Witten, Germany
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Lin DT, Wu J, Holstein D, Upadhyay G, Rourk W, Muller E, Lechleiter JD. Ca2+ signaling, mitochondria and sensitivity to oxidative stress in aging astrocytes. Neurobiol Aging 2005; 28:99-111. [PMID: 16359757 DOI: 10.1016/j.neurobiolaging.2005.11.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Revised: 10/31/2005] [Accepted: 11/09/2005] [Indexed: 11/30/2022]
Abstract
Age-related changes in astrocytes that could potentially affect neuroprotection have been largely unexplored. To test whether astrocyte function was diminished during the aging process, we examined cell growth, Ca2+ signaling, mitochondrial membrane potential (DeltaPsi) and neuroprotection of NGF-differentiated PC12 cells. We observed that cell growth was significantly slower for astrocytes cultured from old (26-29 months) mice as compared to young (4-6 months) mice. DeltaPsis in old astrocytes were also more depolarized (lower) than in young astrocytes and old astrocytes showed greater sensitivity to the oxidant tert-butyl hydrogen peroxide (t-BuOOH). ATP-induced Ca2+ responses in old astrocytes were consistently larger in amplitude and more frequently oscillatory than in young astrocytes, which may be attributable to lower mitochondrial Ca2+ sequestration. Finally, NGF-differentiated PC12 cells that were co-cultured with old astrocytes were significantly more sensitive to t-BuOOH treatment than co-cultures of NGF-differentiated PC12 cells with young astrocytes. Together, these data demonstrate that astrocyte physiology is significantly altered during the aging process and that the astrocyte's ability to protect neurons is compromised.
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Affiliation(s)
- Da-Ting Lin
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900, United States
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Israelson A, Arzoine L, Abu-hamad S, Khodorkovsky V, Shoshan-Barmatz V. A Photoactivable Probe for Calcium Binding Proteins. ACTA ACUST UNITED AC 2005; 12:1169-78. [PMID: 16298296 DOI: 10.1016/j.chembiol.2005.08.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2005] [Revised: 07/18/2005] [Accepted: 08/10/2005] [Indexed: 11/24/2022]
Abstract
Ca2+ as a signaling molecule carries information pivotal to cell life and death via its reversible interaction with a specific site in a protein. Although numerous Ca2+-dependent activities are known, the proteins responsible for some of these activities remain unidentified. We synthesized and characterized a photoreactive reagent, azido ruthenium (AzRu), which interacts specifically with Ca2+ binding proteins and strongly inhibits their Ca2+-dependent activities, regardless of their catalytic mechanisms or functional state as purified proteins, embedded in the membrane or in intact cells. As expected from a Ca2+ binding protein-specific reagent, AzRu had no effect on Ca2+-independent and Mg2+-dependent activities. Az103Ru covalently bound, and specifically labeled, known Ca2+ binding proteins. AzRu is a photoreactive reagent that provides an approach for identification of Ca2+ binding proteins, characterization of their binding sites, and exploration of new Ca2+-dependent processes.
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Affiliation(s)
- Adrian Israelson
- Department of Life Sciences and The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva 84713, Israel
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50
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Calcium binding proteins in selective vulnerability of motor neurons. NEURODEGENER DIS 2005. [DOI: 10.1017/cbo9780511544873.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] Open
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