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Fox CA, Lethcoe K, Ryan RO. Calcium-induced release of cytochrome c from cardiolipin nanodisks: Implications for apoptosis. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183722. [PMID: 34400138 PMCID: PMC8464532 DOI: 10.1016/j.bbamem.2021.183722] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/19/2021] [Accepted: 07/29/2021] [Indexed: 06/13/2023]
Abstract
Miniature bilayer membranes comprised of phospholipid and an apolipoprotein scaffold, termed nanodisks (ND), have been used in binding studies. When ND formulated with cardiolipin (CL), but not phosphatidylcholine, were incubated with cytochrome c, FPLC gel filtration chromatography provided evidence of a stable binding interaction. Incubation of CL ND with CaCl2 resulted in a concentration-dependent increase in sample turbidity caused by ND particle disruption. Prior incubation of CL ND with cytochrome c increased CL ND sensitivity to CaCl2-induced effects. Centrifugation of CaCl2-treated CL ND samples yielded pellet and supernatant fractions. Whereas the ND scaffold protein, apolipophorin III, was recovered in the pellet fraction along with CL, the majority of the cytochrome c pool was in the supernatant fraction. Moreover, when cytochrome c CL ND were incubated with CaCl2 at concentrations below the threshold to induce ND particle disruption, FPLC analysis showed that cytochrome c was released. Pre-incubation of CL ND with CaCl2 under conditions that do not disrupt ND particle integrity prevented cytochrome c binding to CL ND. Thus, competition between Ca2+ and cytochrome c for a common binding site on CL modulates cytochrome c binding and likely plays a role in its dissociation from CL-rich cristae membranes in response to apoptotic stimuli.
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Affiliation(s)
- Colin A Fox
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, United States of America
| | - Kyle Lethcoe
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, United States of America
| | - Robert O Ryan
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, United States of America.
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2
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Lebègue E, Louro RO, Barrière F. Electrochemical Detection of pH-Responsive Grafted Catechol and Immobilized Cytochrome c onto Lipid Deposit-Modified Glassy Carbon Surface. ACS OMEGA 2018; 3:9035-9042. [PMID: 31459037 PMCID: PMC6644398 DOI: 10.1021/acsomega.8b01425] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 07/31/2018] [Indexed: 06/02/2023]
Abstract
The electrochemical systems of both grafted catechol as a pH-responsive electrophore and immobilized cytochrome c as a model redox protein are detected by cyclic voltammetry at an optimized lipid deposit-modified glassy carbon electrode. The catechol covalent grafting is successfully performed by the one-pot/three-step electrochemical reduction of 3,4-dihydroxybenzenediazonium salts generated in situ from 4-nitrocatechol. The resulting glassy carbon electrode electrochemically modified by grafted catechol species is evaluated as an efficient electrochemical pH sensor. The optimized molar ratio for the lipid deposit, promoting cytochrome c electrochemical activity in solution onto glassy carbon electrode, is reached for the lipid mixture composed of 75% 1,2-dioleoyl-sn-glycero-3-phosphocholine and 25% cardiolipin. Cytochrome c immobilization into the optimized supported lipid deposit is efficiently achieved by cyclic voltammetry (10 cycles) recorded at the modified glassy carbon electrode in a cytochrome c solution. The pH-dependent redox response of the grafted catechol and that of the immobilized cytochrome c are finally detected at the same lipid-modified glassy carbon electrode without alteration of their structure and electrochemical properties in the pH range 5-9.
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Affiliation(s)
- Estelle Lebègue
- Univ Rennes, CNRS,
Institut des Sciences Chimiques de Rennes—UMR 6226, F-35000 Rennes, France
| | - Ricardo O. Louro
- Instituto de Tecnologia Química
e Biológica, António Xavier, Universidade NOVA de Lisboa, 2780-157 Oeiras, Portugal
| | - Frédéric Barrière
- Univ Rennes, CNRS,
Institut des Sciences Chimiques de Rennes—UMR 6226, F-35000 Rennes, France
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3
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Lebègue E, Smida H, Flinois T, Vié V, Lagrost C, Barrière F. An optimal surface concentration of pure cardiolipin deposited onto glassy carbon electrode promoting the direct electron transfer of cytochrome-c. J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2017.12.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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4
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de Oliveira MR, Nabavi SF, Nabavi SM, Jardim FR. Omega-3 polyunsaturated fatty acids and mitochondria, back to the future. Trends Food Sci Technol 2017. [DOI: 10.1016/j.tifs.2017.06.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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5
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Shoshan-Barmatz V, Krelin Y, Shteinfer-Kuzmine A. VDAC1 functions in Ca 2+ homeostasis and cell life and death in health and disease. Cell Calcium 2017; 69:81-100. [PMID: 28712506 DOI: 10.1016/j.ceca.2017.06.007] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/21/2017] [Accepted: 06/21/2017] [Indexed: 01/15/2023]
Abstract
In the outer mitochondrial membrane (OMM), the voltage-dependent anion channel 1 (VDAC1) serves as a mitochondrial gatekeeper, controlling the metabolic and energy cross-talk between mitochondria and the rest of the cell. VDAC1 also functions in cellular Ca2+ homeostasis by transporting Ca2+ in and out of mitochondria. VDAC1 has also been recognized as a key protein in mitochondria-mediated apoptosis, contributing to the release of apoptotic proteins located in the inter-membranal space (IMS) and regulating apoptosis via association with pro- and anti-apoptotic members of the Bcl-2 family of proteins and hexokinase. VDAC1 is highly Ca2+-permeable, transporting Ca2+ to the IMS and thus modulating Ca2+ access to Ca2+ transporters in the inner mitochondrial membrane. Intra-mitochondrial Ca2+ controls energy metabolism via modulating critical enzymes in the tricarboxylic acid cycle and in fatty acid oxidation. Ca2+ also determines cell sensitivity to apoptotic stimuli and promotes the release of pro-apoptotic proteins. However, the precise mechanism by which intracellular Ca2+ mediates apoptosis is not known. Here, the roles of VDAC1 in mitochondrial Ca2+ homeostasis are presented while emphasizing a new proposed mechanism for the mode of action of pro-apoptotic drugs. This view, proposing that Ca2+-dependent enhancement of VDAC1 expression levels is a major mechanism by which apoptotic stimuli induce apoptosis, position VDAC1 oligomerization at a molecular focal point in apoptosis regulation. The interactions of VDAC1 with many proteins involved in Ca2+ homeostasis or regulated by Ca2+, as well as VDAC-mediated control of cell life and death and the association of VDAC with disease, are also presented.
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Affiliation(s)
- Varda Shoshan-Barmatz
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
| | - Yakov Krelin
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Anna Shteinfer-Kuzmine
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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6
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Broniatowski M, Urbaś M. Interactions of two structurally related anionic phospholipids cardiolipin and phosphatidylglycerol with phospholipase A2. Langmuir monolayer studies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:155-166. [DOI: 10.1016/j.bbamem.2016.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 11/15/2016] [Accepted: 11/16/2016] [Indexed: 12/27/2022]
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7
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Xiao F, Yue L, Li S, Li X. Conjugation of cytochrome c with ferrocene-terminated hyperbranched polymer and its influence on protein structure, conformation and function. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2016; 162:69-74. [PMID: 26978787 DOI: 10.1016/j.saa.2016.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 06/05/2023]
Abstract
Interaction mechanism of a new hyperbranched polyurethane-based ferrocene (HPU-Fc) with cytochrome c (cyt c) and cyt c structure and conformation change induced by HPU-Fc were investigated using cyclic voltammogram(CV), differential pulse voltammetry (DPV), circular dichroism (CD), fluorescence, synchronous fluorescence and absorbance spectroscopy technique. The peroxidase activity of cyt c in the presence of HPU-Fc was also studied. The structure and conformation of protein are relatively stable at moderate concentration of HPU-Fc without obvious perturbation of the heme pocket and significant changes in protein secondary structure. Conjugation of cyt c with excessive HPU-Fc (over about 3 times of cyt c) slightly changed the α-helix structure in protein, disturbed the microenvironment around heme as well as away from the heme crevice, which caused the changes of the electrochemical behavior and the absorption spectra. Reasonable amount of HPU-Fc has no significant influence on the protein enzymatic activity, while excess HPU-Fc may cause a conformation not suitable for H2O2 activation and guaiacol oxidation. The interaction of HPU-Fc with cyt c and the conservation of protein function at suitable HPU-Fc amount make prepared complex promising for the synergistic anticancer therapy.
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Affiliation(s)
- Fengjuan Xiao
- School of Material Science and Engineering, Shijiazhuang Tiedao University, Hebei Provincial Key Laboratory of Traffic Engineering Materials, No. 17 North 2nd-Ring East Road, Shijiazhuang 050043, Hebei Province, China.
| | - Lin Yue
- School of Material Science and Engineering, Shijiazhuang Tiedao University, Hebei Provincial Key Laboratory of Traffic Engineering Materials, No. 17 North 2nd-Ring East Road, Shijiazhuang 050043, Hebei Province, China.
| | - Song Li
- School of Material Science and Engineering, Shijiazhuang Tiedao University, Hebei Provincial Key Laboratory of Traffic Engineering Materials, No. 17 North 2nd-Ring East Road, Shijiazhuang 050043, Hebei Province, China.
| | - Xinxin Li
- School of Material Science and Engineering, Shijiazhuang Tiedao University, Hebei Provincial Key Laboratory of Traffic Engineering Materials, No. 17 North 2nd-Ring East Road, Shijiazhuang 050043, Hebei Province, China.
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8
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Chen H, Gao W, Yang Y, Guo S, Wang H, Wang W, Zhang S, Zhou Q, Xu H, Yao J, Tian Z, Li B, Cao W, Zhang Z, Tian Y. Inhibition of VDAC1 prevents Ca²⁺-mediated oxidative stress and apoptosis induced by 5-aminolevulinic acid mediated sonodynamic therapy in THP-1 macrophages. Apoptosis 2015; 19:1712-26. [PMID: 25342393 DOI: 10.1007/s10495-014-1045-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Ultrasound combined with endogenous protoporphyrin IX derived from 5-aminolevulinic acid (ALA-SDT) is known to induce apoptosis in multiple cancer cells and macrophages. Persistent retention of macrophages in the plaque has been implicated in the pathophysiology and progression of atherosclerosis. Here we investigated the effects of inhibition of voltage-dependent anion channel 1 (VDAC1) on ALA-SDT-induced THP-1 macrophages apoptosis. Cells were pre-treated with VDAC1 inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) disodium salt for 1 h or downregulated VDAC1 expression by small interfering RNA and exposed to ultrasound. Cell viability was assessed by MTT assay, and cell apoptosis along with necrosis was evaluated by Hoechst 33342/propidium iodide staining and flow cytometry. Levels of cytochrome c release was assessed by confocal microscope and Western blot. The levels of full length caspases, caspase activation, and VDAC isoforms were analyzed by Western blot. Intracellular reactive oxygen species generation, mitochondrial membrane permeability, and intracellular Ca(2+) [Ca(2+)]i levels were measured with fluorescent probes. We confirmed that the pharmacological inhibition of VDAC1 by DIDS notably prevented ALA-SDT-induced cell apoptosis in THP-1 macrophages. Additionally, DIDS significantly inhibited intracellular ROS generation and apoptotic biochemical changes such as inner mitochondrial membrane permeabilization, loss of mitochondrial membrane potential, cytochrome c release and activation of caspase-3 and caspase-9. Moreover, ALA-SDT elevated the [Ca(2+)]i levels and it was also notably reduced by DIDS. Furthermore, both of intracellular ROS generation and cell apoptosis were predominately inhibited by Ca(2+) chelating reagent BAPTA-AM. Intriguingly, ALA-treatment markedly augmented VDAC1 protein levels exclusively, and the downregulation of VDAC1 expression by specific siRNA also significantly abolished cell apoptosis. Altogether, these results suggest that VDAC1 plays a crucial role in ALA-SDT-induced THP-1 macrophages apoptosis, and targeting VDAC1 is a potential way regulating macrophages apoptosis, a finding that may be relevant to therapeutic strategies against atherosclerosis.
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Affiliation(s)
- Haibo Chen
- Department of Cardiology, The First Affiliated Hospital, Cardiovascular Institute, Harbin Medical University, 23 Youzheng Street, Harbin, 150001, Heilongjiang, China
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9
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Perhirin A, Kraffe E, Marty Y, Quentel F, Elies P, Gloaguen F. Electrochemistry of cytochrome c immobilized on cardiolipin-modified electrodes: a probe for protein-lipid interactions. Biochim Biophys Acta Gen Subj 2013; 1830:2798-803. [PMID: 23266496 DOI: 10.1016/j.bbagen.2012.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 11/15/2012] [Accepted: 12/10/2012] [Indexed: 11/26/2022]
Abstract
Electrochemistry of cytochrome c (cyt c) immobilized on a cardiolipin (CL)/phosphatidylcholine (PC) film supported on a glassy carbon electrode was investigated using variable-frequency AC voltammetry. At low ionic strength, we observed two redox-active subpopulations characterized by distinct values of potential (E1/2) and electron transfer rate constant (k(ET)). At high ionic strength, only one subpopulation was detected, consistent with the existence of very stable cyt c-CL adducts, most probably formed by hydrophobic interactions between the protein and the fatty acid (FA) chains carried by CL. This subpopulation exhibits a comparatively high k(ET) value (> 300 s(-1)) apparently changing with the structure of the FA chains of CL, i.e. 18:2(n - 6) or 14:0. Our study suggests that electrochemistry can be a useful technique for probing protein-lipid interactions, and more particularly the role played by the specific structure of the FA chains of CL on cyt c binding.
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Affiliation(s)
- Antoine Perhirin
- CEMCA, UMR 6521, CNRS, Université de Bretagne Occidentale, Brest, France
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10
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Keinan N, Pahima H, Ben-Hail D, Shoshan-Barmatz V. The role of calcium in VDAC1 oligomerization and mitochondria-mediated apoptosis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1745-54. [PMID: 23542128 DOI: 10.1016/j.bbamcr.2013.03.017] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 03/19/2013] [Accepted: 03/21/2013] [Indexed: 11/17/2022]
Abstract
The voltage-dependent anion channel (VDAC), located at the outer mitochondria membrane (OMM), mediates interactions between mitochondria and other parts of the cell by transporting anions, cations, ATP, Ca(2+), and metabolites. Substantial evidence points to VDAC1 as being a key player in apoptosis, regulating the release of apoptogenic proteins from mitochondria, such as cytochrome c, and interacting with anti-apoptotic proteins. Recently, we demonstrated that VDAC1 oligomerization is a general mechanism common to numerous apoptogens acting via different initiating cascades and proposed that a protein-conducting channel formed within a VDAC1 homo/hetero oligomer mediates cytochrome c release. However, the molecular mechanism responsible for VDAC1 oligomerization remains unclear. Several studies have shown that mitochondrial Ca(2+) is involved in apoptosis induction and that VDAC1 possesses Ca(2+)-binding sites and mediates Ca(2+) transport across the OMM. Here, the relationship between the cellular Ca(2+) level, [Ca(2+)]i, VDAC1 oligomerization and apoptosis was studied. Decreasing [Ca(2+)]i using the cell-permeable Ca(2+) chelating reagent BAPTA-AM was found to inhibit VDAC1 oligomerization and apoptosis, while increasing [Ca(2+)]i using Ca(2+) ionophore resulted in VDAC1 oligomerization and apoptosis induction in the absence of apoptotic stimuli. Moreover, induction of apoptosis elevated [Ca(2+)]i, concomitantly with VDAC1 oligomerization. AzRu-mediated inhibition of mitochondrial Ca(2+) transport decreased VDAC1 oligomerization, suggesting that mitochondrial Ca(2+) is required for VDAC1 oligomerization. In addition, increased [Ca(2+)]i levels up-regulate VDAC1 expression. These results suggest that Ca(2+) promotes VDAC1 oligomerization via activation of a yet unknown signaling pathway or by increasing VDAC1 expression, leading to apoptosis. This article is part of a Special Issue entitled: 12th European Symposium on Calcium.
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Affiliation(s)
- Nurit Keinan
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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11
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Shoshan-Barmatz V, Mizrachi D, Keinan N. Oligomerization of the Mitochondrial Protein VDAC1. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:303-34. [DOI: 10.1016/b978-0-12-386931-9.00011-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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12
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Moon SH, Jenkins CM, Kiebish MA, Sims HF, Mancuso DJ, Gross RW. Genetic ablation of calcium-independent phospholipase A(2)γ (iPLA(2)γ) attenuates calcium-induced opening of the mitochondrial permeability transition pore and resultant cytochrome c release. J Biol Chem 2012; 287:29837-50. [PMID: 22778252 DOI: 10.1074/jbc.m112.373654] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Herein, we demonstrate that calcium-independent phospholipase A(2)γ (iPLA(2)γ) is a critical mechanistic participant in the calcium-induced opening of the mitochondrial permeability transition pore (mPTP). Liver mitochondria from iPLA(2)γ(-/-) mice were markedly resistant to calcium-induced swelling in the presence or absence of phosphate in comparison with wild-type littermates. Furthermore, the iPLA(2)γ enantioselective inhibitor (R)-(E)-6-(bromomethylene)-3-(1-naphthalenyl)-2H-tetrahydropyran-2-one ((R)-BEL) was markedly more potent than (S)-BEL in inhibiting mPTP opening in mitochondria from wild-type liver in comparison with hepatic mitochondria from iPLA(2)γ(-/-) mice. Intriguingly, low micromolar concentrations of long chain fatty acyl-CoAs and the non-hydrolyzable thioether analog of palmitoyl-CoA markedly accelerated Ca(2+)-induced mPTP opening in liver mitochondria from wild-type mice. The addition of l-carnitine enabled the metabolic channeling of acyl-CoA through carnitine palmitoyltransferases (CPT-1/2) and attenuated the palmitoyl-CoA-mediated amplification of calcium-induced mPTP opening. In contrast, mitochondria from iPLA(2)γ(-/-) mice were insensitive to fatty acyl-CoA-mediated augmentation of calcium-induced mPTP opening. Moreover, mitochondria from iPLA(2)γ(-/-) mouse liver were resistant to Ca(2+)/t-butyl hydroperoxide-induced mPTP opening in comparison with wild-type littermates. In support of these findings, cytochrome c release from iPLA(2)γ(-/-) mitochondria was dramatically decreased in response to calcium in the presence or absence of either t-butyl hydroperoxide or phenylarsine oxide in comparison with wild-type littermates. Collectively, these results identify iPLA(2)γ as an important mechanistic component of the mPTP, define its downstream products as potent regulators of mPTP opening, and demonstrate the integrated roles of mitochondrial bioenergetics and lipidomic flux in modulating mPTP opening promoting the activation of necrotic and necroapoptotic pathways of cell death.
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Affiliation(s)
- Sung Ho Moon
- Department of Medicine, Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine, St. Louis, MO 63110, USA
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13
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14
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Jou MJ, Peng TI, Hsu LF, Jou SB, Reiter RJ, Yang CM, Chiao CC, Lin YF, Chen CC. Visualization of melatonin's multiple mitochondrial levels of protection against mitochondrial Ca(2+)-mediated permeability transition and beyond in rat brain astrocytes. J Pineal Res 2010; 48:20-38. [PMID: 19925580 DOI: 10.1111/j.1600-079x.2009.00721.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Melatonin protects cells against various types of oxidative stress-induced apoptosis due primarily to its ability to effectively scavenge pathological and disease condition-augmented generation of mitochondrial reactive oxygen species (mROS). Once produced, mROS indiscriminately damage mitochondrial components and more importantly they crucially activate directly the mitochondrial permeability transition (MPT), one of the critical mechanisms for initiating post mitochondrial apoptotic signaling. Whether or not melatonin targets directly the MPT, however, remains inconclusive, particularly during oxidative stress. This study, thus, investigated this possibility of an 'oxidation free Ca(2+) stress' in the presence of vitamin E after ionomycin exposure as a sole Ca(2+)-mediated MPT in order to exclude melatonin's primary antioxidative effects as well as Ca(2+)-mediated oxidative stress. The studies were carried out using cultured rat brain astrocytes RBA-1. With the application of laser scanning multiple fluorescence imaging microscopy, we visualized for the first time multiple mitochondrial protective effects provided by melatonin during Ca(2+) stress. First, melatonin, due to its primary antioxidative actions, completely prevented mCa(2+)-induced mROS formation during ionomycin exposure. Secondly, when melatonin(')s antioxidative effects were prevented due to the addition of vitamin E, melatonin significantly prevented mCa(2+)-mediated MPT and apoptosis suggesting its direct targeting of the MPT. Surprisingly, in the presence of cyclosporin A, a MPT inhibitor, melatonin reduced further mCa(2+)-mediated apoptosis during ionomycin exposure also suggesting its targeting beyond the MPT. As astrocytes are actively involve in regulating synaptic transmission and neurovascular coupling in the CNS, these multiple mitochondrial layers of protection provided by melatonin against mCa(2+)-and/or mROS-mediated apoptosis in astrocytes may be crucial for future therapeutic prevention and treatment of astrocyte-mediated neurodegenerative diseases in the CNS.
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Affiliation(s)
- Mei-Jie Jou
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.
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15
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Zhou N, Chen Z, Zhang D, Li G. Electrochemical Assay of Human Islet Amyloid Polypeptide and Its Aggregation. SENSORS 2008; 8:5987-5995. [PMID: 27873853 PMCID: PMC3705543 DOI: 10.3390/s8095987] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 09/11/2008] [Accepted: 09/22/2008] [Indexed: 12/29/2022]
Abstract
Square wave voltammetry is used in this work to detect human islet amyloid polypeptide (hIAPP) by using the oxidized signal of the tyrosine residue in hIAPP. A detection limit of 1×10-6 M for hIAPP has been obtained. A kinetic study of the aggregation process has been carried out according to the relationship between the anodic peak current in the square wave voltammograms of hIAPP and the incubation period. The results show that the nucleation starts in the first hour of incubation and then, during the next two hours, aggregation may occur rapidly. hIAPP can therefore be monitored with a label-free electrochemical method with low detection limit and high sensitivity. This electrochemical method can be also utilized to study the kinetics of hIAPP aggregation, and it may be also employed to study the conformational changes of the polypeptide.
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Affiliation(s)
- Nandi Zhou
- Laboratory of Biosensing Technology, School of Life Science, Shanghai University, Shanghai 200444, P.R. China
- Department of Biochemistry and National Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, P.R. China
| | - Zhenyu Chen
- Laboratory of Biosensing Technology, School of Life Science, Shanghai University, Shanghai 200444, P.R. China
| | - Dongmei Zhang
- Department of Biochemistry and National Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, P.R. China
| | - Genxi Li
- Laboratory of Biosensing Technology, School of Life Science, Shanghai University, Shanghai 200444, P.R. China.
- Department of Biochemistry and National Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, P.R. China.
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Zhao J, Meng F, Zhu X, Han K, Liu S, Li G. Electrochemistry of Mitochondria: A New Way to Understand Their Structure and Function. ELECTROANAL 2008. [DOI: 10.1002/elan.200704205] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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Ott M, Zhivotovsky B, Orrenius S. Role of cardiolipin in cytochrome c release from mitochondria. Cell Death Differ 2007; 14:1243-7. [PMID: 17431425 DOI: 10.1038/sj.cdd.4402135] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- M Ott
- Institute of Environmental Medicine, Karolinska Institutet, Box 210, S-171 77 Stockholm, Sweden
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